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G14 Health effects of mercury

Monday, 25 July, 2011

MG14-P1 — 11:00-12:00 and 17:30-18:30
EFFECTS OF METHYLMERCURY ON DOPAMINE RELEASE IN MN9D NEURONAL CELLS
Authors: SHAO, Yueting1, CHAN, Laurie1
(1)Health Sciences Program, University of Northern British Columbia, Prince George, BC, Canada, shaoy@unbc.ca

Dopamine depletion was one of the pathogenic characteristics of Parkinson’s disease (PD). Epidemiological evidence has shown associations between prevalence of Parkinson’s disease and environmental exposure to pesticides and heavy metals, but the mechanisms of action is unknown. The objective of this study was to investigate effects and underlying mechanisms of methylmercury (MeHg) on a dopaminergic neuronal cell line, MN9D and compare that to 1-methyl-4-phenylpyridinium (MPP+), a well-established agent associated with pathogenesis of PD. MN9D cells were exposed to MeHg (1-15µM) and MPP+ (10-800µM) for 24h or 48h. The data shows MeHg and MPP+ induce the cell death both time and dose dependently. MeHg also decreased the release of extracellular dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) that similar to the effects of MPP+. There was an increase in DA metabolites as shown by the increase of DOPAC+HVA/DA ratio. At the same time, both MeHg and MPP+ down regulated the expression of tyrosine hydroxylase (TH) and dopamine transporter (DAT) at the mRNA and protein levels. Expression of the α-Synuclein (α-Syn), a hallmark of neuropathological indicator of PD, was also up-regulated between the two treatments at the mRNA level but not at the protein level. These findings suggest that MeHg can disrupt the synthesis, the uptake and the metabolism of DA as well as alter the biology of α-Syn. MeHg can be a risk factor linked to the pathogenesis of PD.

MG14-P2 — 11:00-12:00 and 17:30-18:30
TOTAL MERCURY IN BREAST MILK OF URBAN AND RIVERINE MOTHERS ALONG THE RIO MADEIRA, WESTERN AMAZON.
Authors: VIEIRA, Solange M.1, GALVÃO, Roberta C.F.1, HOLANDA, Igor B.B.1, DE ALMEIDA, Ronaldo1, DÓREA, José G.2, BASTOS, Wanderley R1
(1) Universidade Federal de Rondônia, solangevieira@ibest.com.br; (2) Universidade de Brasília;

Fish eating populations of the Amazon are exposed to methylmercury. Besides high fish consumption, extended breastfeeding is also a hallmark of traditional living. We investigated the total mercury concentrations in milk of 157 mothers living in the capital city of Porto Velho (90) and in traditional communities (Calama, Nazaré, Santa Catarina, Terra Caída, São Carlos e Demarcação) along the banks of the Rio Madeira (67). Frequency of fish consumption and dental amalgam were part of the information collected from the volunteering mothers. Total Hg in breast milk was determined by cold vapor AAS (FIMS-400, Perkin-Elmer) after sample digestion in HNO3-H2SO4-KMnO4. Mean total Hg in milk of urban mothers (0.78±1.18 µg/kg) was lower than that found in milk of riverine mothers (2.55±1.86 µg/kg); the difference of means between groups was statistically significant (p=0.0000). In the riverine mothers, total breast-milk Hg was significantly (Spearman r=0.3096, p=0.0069) correlated with frequency of fish consumption but was not significantly correlated with dental amalgam fillings. However, in mothers from Porto Velho with relatively lower fish consumption rates, there was no significant correlation between total milk-Hg concentrations with frequency of fish consumption or number of dental amalgam fillings. Overall, the asymmetric distribution of milk-Hg concentrations placed 51% of breast milk Hg concentrations from riverine mothers above 2µg/kg (world median concentrations), which contrasts with 8% of milk Hg concentrations from mothers of Porto Velho. In the social and demographic transitioning occurring in the Brazilian Amazon, fish is losing its centrality in the diet of mothers; as a consequence fish-Hg exposure has been drastically reduced in urban populations. However, relatively high fish consumption in riverine populations can still impact total milk-Hg concentrations.

Financial support:
CT-Biotecnologia (Grant 553269/2005-4); INCT-INPeTAm/CNPq/MCT (Grant 573695/2008-3); Santo Antonio Energia (Grant UNIR/RIOMAR 005/2009).

MG14-P3 — 11:00-12:00 and 17:30-18:30
HEALTH SURVEY IN THE METHYLMERCURY-POLLUTED AREA IN 2009
Author: TAKAOKA, Shigeru1
(1)Minamata Kyoritsu Hospital, stakaoka@x.email.ne.jp

Background: Around Minamata districts, many of the residents have avoided receiving health examination on Minamata disease, because residents have been afraid of being discriminated. In order to provide residents the opportunities for medical examination, we conducted a health survey along the Shiranui Seashore.

Methods: On September 20 and 21, 2009, inquiry and neurological examinations of inhabitants were performed. We categorized subjects into six according to the present address and residential history in the designated districts where compensation law of public nuisance is applicable, and compared the symptoms and examined signs.

Results: One thousand and forty-four residents were examined. The admission of data collection was obtained from 974 subjects. There was a family history of Minamata disease in half of the subjects, but subjects who have ever examined for Minamata disease in the past were only 112 (11%). People in were classified by the following criteria. People who had lived in the designated place before 1968 were 807. They were subclassified into group A: Minamata-Ashikita (232), group B: Amakusa-Yatsushiro (166), group C: Izumi-Akune (238), and group D: who were living other places (171). People who had not lived in the designated place were classified as group E (108). People who were born in or moved into the designated place after 1969 were classified as group F (59). Average age was 62.3+-11.8. The subjective symptoms were as follows: Muscle cramps 898 (92%), numbness 896 (92%), stumbling 744 (76%), and difficulty in circumferential vision 591 (61%). Positive neurological signs by medical doctors were as follows: visual constriction 227 (23%), straight line gait instability 485 (50%), superficial sensory disturbance in four limbs 775 (80%), systemic superficial sensory disturbance 246 (25%).

Discussion: Symptoms and signs were characteristic for chronic methylmercury poisoning and symptomatic patterns in each group were closely resembled including group E and F. These residents are only a tip of the iceberg, and health hazards by methylmercury are thought to have been spreading chronically and spatially. Further examinations are necessary even now.

MG14-P4 — 11:00-12:00 and 17:30-18:30
THE EFFECTIVENESS OF BIOMONITORING AS AN INTERVENTION AGAINST METHYLMERCURY EXPOSURE
Author: KNOBELOCH, Lynda1
(1) Wisconsin Dept of Health Services, lknobeloch@gmail.com

During 2004, the Wisconsin Department of Health Services assessed fish consumption and methylmercury exposure among 2,031 men and women. Adults who responded to a statewide recruitment were sent a hair collection kit and questionnaire that requested basic demographic and dietary information. Personalized result letters were sent to all participants. For those whose hair mercury levels were greater than 1 µg/g these letters stated that their result exceeded the safe guideline for mercury exposure and advised them to reduce their intake of large, predatory fish. All other participants were informed that mercury exposure was not an issue for them and encouraged to continue to eat fish as part of a healthy, balanced diet.

In 2008, approximately 4 years after the baseline study was completed, follow-up questionnaires and hair sampling kits were mailed to each of the study participants. These materials were returned by 1,139 individuals representing a response rate of 61% among those who received the study packet. Compared to non-responders, follow-up study participants had higher baseline hair mercury levels, were more likely to be men and ate more fish. While baseline and follow-up fish intake estimates were essentially unchanged at 7.9 to 7.7 servings per month, almost 30% of the cohort reported eating different types of fish or smaller fish in 2008. The number of people who had a hair mercury level >1 µg/g fell from 300 to 206 and the maximum hair mercury level fell from 15.2 to 6.0 µg/g. These findings suggest that biomonitoring coupled with personalized dietary advice had a long-term effect on behavior and significantly reduced the risk of methylmercury-related health problems among study volunteers.

MG14-P5 — 11:00-12:00 and 17:30-18:30
CELLULAR RESPONSE TO SEAFOOD NUTRIENTS AND METHYLMERCURY EXPOSURE
Authors: KAUR, Parvinder1, SYVERSEN, Tore1, EVJE, Lars 1, HEGGLAND, Ingrid1
(1) Department of Neurosciene, parvinder.kaur@ntnu.no

Methylmercury (MeHg), an environmental toxicant primarily found in seafood, poses a dilemma to consumers and regulatory authorities given the nutritional benefits of fish consumption versus possible adverse neurological damage caused by MeHg. We addressed this issue by estimating the cellular response to dietary nutrients as well as neurotoxic exposures from MeHg to determine the risks and benefits of fish consumption.

For this purpose, the effect of seafood nutrients such as glutathione, fatty acids, micronutrients and vitamins in modulating MeHg-induced neurotoxicity were investigated in C6 and primary astrocytes as glial and B35 and primary neurons as neuronal models. The cells were incubated with N-acetyl cysteine (NAC), di-ethyl maleate (DEM), Docosahexaenoic acid (DHA), Selenomethionine (SeM) and 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) for 12 or 24 hrs. and then exposed to 5µM or 10µM MeHg for 50 min. The intracellular Glutathione (GSH), DHA, Selenium and MeHg content was measured by fluorescent indicator monochlorobimane (MCB), Gas Chromatography-Flame ionization detector (GC-FID), high resolution-inductively coupled plasma mass spectrometry (HR-ICPMS) and 14C-labelled MeHg. Mitochondrial activity (MTT) and reactive oxygen species (ROS) content were selected as the endpoints for measuring cytotoxicity and were measured by MTT reduction, and fluorescent indicator -chloro methyl derivative of di-chloro di-hydro fluorescein diacetate (CMH2DCFDA).

MeHg treatment resulted in significant (p<0.05) decrease in GSH content, MTT activity and increase in ROS levels in C6 and primary cells as compared to control group. In addition, depletion of intracellular GSH by treatment with 3mM DEM led to increase in cell-associated MeHg and MeHg-induced ROS. Conversely, 250µM NAC supplementation increased intracellular GSH and provided protection against MeHg-induced oxidative stress and attenuated MeHg-induced cytotoxicity. In addition, 30µM DHA, 50µM Trolox and SeM preincubated cells also exhibited reduction in (p<0.001) MeHg-induced ROS. Taken together, these studies, establish that preincubation with seafood nutrients protect against MeHg-induced ROS. These results support the hypothesis that protection against intracellular oxidative stress is among one of the major mechanisms responsible for neuroprotection against MeHg-containing fish diet.

MG14-P6 — 11:00-12:00 and 17:30-18:30
MERCURY IN DRIED BLOOD SPOTS FROM NEWBORNS
Authors: MCCANN, Patricia1, WOLF, Carrie R.2, BRENNER, Jeffrey J. 2, EDHLUND, Betsy L.2, SKORICH, Suzanne S.2, HERBRANDSON, Carl2, MESSING, Rita B. 2, DUNLAP, Sara J.2, ANDERSON, Henry A. 3, HOFFMAN, Gary L.4
(1) Minnesota Dept of Health, patricia.mccann@state.mn.us; (2) Minnesota Department of Health; (3) Wisconsin Division of Public Health; (4) Wisconsin State Laboratory of Hygiene.

Total mercury was measured in dried blood spots from approximately 1500 infants born 2008 through 2010 to mothers residing in the US portion of the Lake Superior Basin. The purpose of this study was to determine the range of mercury concentrations in these infants and to assess feasibility of using infant blood as an indicator of mercury exposure. Although there are considerable data on the levels of mercury in fish from the Lake Superior basin there has been limited human biomonitoring for mercury. These are the first data to describe the magnitude or extent of potentially harmful in-utero exposures in this population. Results will be summarized and compared to concentrations of mercury reported in maternal blood and cord blood. A wide range of concentrations were found. These data provide evidence of mercury exposure. Potential exposure routes, including fish and other sources, and recommendations for further research will be discussed.

MG14-P7 — 11:00-12:00 and 17:30-18:30
EFFECT OF DIETARY HABITS ON BIOACCESSIBILITY OF MERCURY FROM FISH
Authors: OUEDRAOGO, Ousséni1, AMYOT, Marc1
(1) Université de Montréal, ousseno@yahoo.fr

Fish consumption is the main source of human exposure to mercury. Studies from specific human populations have reported Hg levels lower than those modeled from consumption data. These discrepancies between expected and measured Hg levels may be explained by differences in dietary habits such as cooking methods and food components on fish Hg bioavailability. We assessed the effects of three cooking methods (no cooking, frying and boiling) and of the co-ingestion of selected food items (tea, coffee and corn starch) on Hg bioaccessibility in three fish species (tuna, shark and mackerel). Bioaccessibility of Hg and methylmercury (MeHg) was determined by simulated human digestion. Boiling and frying reduced Hg bioaccessibility by 40 % and 60% respectively, compared to raw fish Hg bioaccessibility. Black coffee, green and black tea significantly reduced fish Hg bioaccessibility by 50- 60%, whereas, corn starch did not. This study suggests that fish consumers may reduce Hg exposure by favoring cooked fish over raw fish and by consuming tea or coffee during their meal. Consideration must be given to the dietary habits such as cooking type and food components in mercury exposure and risk assessment.

MG14-P8 — 11:00-12:00 and 17:30-18:30
BIOMARKERS OF MERCURY EXPOSURE IN TWO EASTERN UKRAINE CITIES
Authors: GIBB, Herman J1, FULCHER, Keri G1, HAVER, Cary E2, KOZLOV, Kostj3, CENTENO, Jose A4, JURGENSON, Vera G5, KOLKER, Allan6, CONKO, Kathryn M6, LANDA, Edward R6, XU, Hanna4
(1) Tetra Tech Sciences, hgibb@sciences.com; (2) ; (3) Ukraine Institute of Occupational Health, Kyiv, Ukraine; (4) Armed Forces Institute of Pathology, Washington, DC; (5) Georgetown University, Washington, DC; (6) U.S. Geological Survey, Reston, VA;

This study evaluates biomarkers of mercury exposure among residents of Horlivka, a city in eastern Ukraine located in an area with geologic and industrial sources of environmental mercury. Residents of Artemivsk, a nearby comparison city outside of the mercury-enriched area were used as control subjects. Samples of urine, blood, hair, and nails were collected from study participants, and a questionnaire was administered to obtain data on age, gender, occupational history, smoking, alcohol consumption, fish consumption, tattoos, dental amalgams, home heating system, education, source of drinking water, and family employment in coal or mercury mines. Median biomarker mercury concentrations in Artemivsk (n = 30) were 0.26 µg/g-Cr (urine), 0.92 µg/L (blood), 0.42 µg/g (hair), 0.11 µg/g (toenails), and 0.09 µg/g (fingernails); median concentrations in Horlivka (n = 31) were 0.15 µg/g-Cr (urine), 1.01 µg/L (blood), 0.14 µg/g (hair), 0.31 µg/g (toenails), and 0.31 µg/g (fingernails). Biomarkers of mercury exposure for study participants from Horlivka and Artemivsk not occupationally exposed to mercury are low in comparison with workers at a mercury recycling facility in Horlivka and in comparison with exposures known to be associated with clinical effects. Blood and urinary mercury did not suggest a higher mercury exposure among Horlivka residents as compared to Artemivsk; however, three individuals living in the immediate vicinity of the mercury mines had elevated blood and urinary mercury, relative to overall results for either city. For a limited number of residents from Horlivka (N=7) and Artemivsk (N=4), environmental samples (vacuum cleaner dust, dust wipes, soil) were collected from their residences. Mercury concentrations in vacuum cleaner dust and soil were good predictors of blood and urinary mercury.

MG14-P9 — 11:00-12:00 and 17:30-18:30
URINARY MERCURY EXCRETION RATE: DIFFERENCES BETWEEN 24H URINE AND OVERNIGHT SPOT URINE SAMPLING AND EFFECT OF URINARY FLOW
Authors: WALLIN, Maria1, AKERSTROM, Magnus1, LUNDH, Thomas2, BARREGARD, Lars1, SALLSTEN, Gerd1
(1) Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital and University of Gothenburg, Sweden, maria.wallin@amm.gu.se; (2) Department of Occupational and Environmental Medicine, Lund University Hospital and Lund University, Sweden;

Urinary mercury (U-Hg) excretion is widely used to assess exposure, body burden or risk of adverse health effects. U-Hg sampling could be done either by 24h urine collection or by spot urine sampling. The aim of this study was to examine possible differences between 24h urine and overnight spot urine sampling and effects of urinary flow (UF) on urinary mercury excretion rate.

Methods
Separate 24h urine (U24) samples and timed overnight spot urine (UON) samples were collected and the volumes were measured in 152 healthy kidney donors before transplantation. U-Hg in the urine samples were analyzed and excretion rates per hour (U-Hg/h) were calculated. Differences between U24 and UON samples were tested using paired t-test and the effect of UF was assessed by linear regression.

Results
The mercury excretion rate (U-Hg/h) was significantly higher in UON samples than in U24 samples (mean 0.082 µg/h vs. 0.075 µg/h, p=0.03). When the study population was divided into men and women, a significantly higher U-Hg/h in UON sample was only seen for women (p=0.05). There were no differences in U-Hg/h or excreted amount U-Hg/24h (mean 1.8 µg/24h, range 0.01 – 10.7 µg/24h) between men and women. No effect of UF was seen for U-Hg/h neither in the total material nor for men or women separately. There were significant correlations between the number of dental amalgam fillings and both the U-Hg/h (in UON and U24), and the excreted amount U-Hg/24h (rp = 0.41-0.46; p<0.001). U-Hg/h (in UON and U24) was about 30% higher in the 4th quartile of amalgam fillings compared to the 1st quartile (p<0.001).

Conclusions
Since U-Hg/h was significantly higher in UON than U24 samples the former will overestimate the U-Hg excretion. The difference was primarily seen for women and could not been explained by an effect of UF.

MG14-P10 — 11:00-12:00 and 17:30-18:30
AGREEMENT BETWEEN URINARY MERCURY CONCENTRATIONS IN 24H URINE AND OVERNIGHT SPOT URINE SAMPLES, USING ADJUSTMENT FOR CREATININE OR SPECIFIC GRAVITY.
Authors: AKERSTROM, Magnus1, LUNDH, Thomas2, BARREGARD, Lars1, SALLSTEN, Gerd1
(1) Occupational and Environmental Medicine, Sahlgrenska University Hospital and University of Gothenburg, magnus.akerstrom@amm.gu.se; (2) Occupational and Environmental Medicine, Lund University Hospital and Lund University;

Urinary mercury (U-Hg) excretion is widely used to assess exposure, body burden or risk of adverse health effects. U-Hg sampling could be done either by 24h urine collection or by spot urine sampling and adjustment for dilution is usually performed using creatinine concentration (U-Crea) or specific gravity (SG). The aim of this study was to examine the agreement between 24h urine and overnight spot urine sampling for unadjusted and adjusted mercury concentrations.

Methods
Separate 24h urine (U24) samples and timed overnight spot urine (UON) samples were collected and the volumes were measured in 152 healthy kidney donors before transplantation. U-Hg, U-Crea and SG in the urine samples were analyzed. SG standard 1.015 was used in the SG adjustment calculations. Differences between U24 and UON samples were tested using paired t-test and the effect of UF was assessed by linear regression.

Results
U-Hg was significantly higher in UON compared to U24 for both unadjusted U-Hg and U-Hg adjusted for U-Crea (U-HgCrea) or SG (U-HgSG). The difference was seen both in the total material and for men and women separately, except for U-HgCrea in men. U-HgCrea and U-HgSG was not affected by the UF. High correlations were seen between U24 and UON for U-Hg, U-HgCrea and U-HgSG (rp=0.68-0.88; p<0.001). However for both unadjusted U-Hg and U-HgSG, overnight samples tend to overestimate the mercury excretion, especially at high U-Hg.

Conclusions
The mercury excretion is higher in UON than U24 samples. Using unadjusted mercury concentrations or mercury concentrations adjusted for specific gravity tend to overestimate the mercury excretion. Creatinine adjustment seems to be the best method.

MG14-P11 — 11:00-12:00 and 17:30-18:30
A PILOT RANDOMIZED CONTROLLED TRIAL TO INCREASE CONSUMPTION OF LOW MERCURY FISH DURING PREGNANCY
Authors: OKEN, Emily1, GUTHRIE, Lauren1, BLOOMINGDALE, Arienne1, KLEINMAN, Ken1, PLATEK, Deborah2, PRICE, Sarah1, HAINES, Jess3, BELLINGER, David4, GILLMAN, Matthew W.1, OLSEN, Sjurdur F.5
(1) Harvard Medical School and Harvard Pilgrim Health Care Institute, emily_oken@hphc.org; (2) Harvard Vanguard Medical Associates; (3) University of Guelph; (4) Children’s Hospital Boston; (5) Statens Serum Institut.

Background: US guidelines recommend that pregnant women limit fish intake to minimize exposure to methylmercury (MeHg), a neurotoxicant to which the developing fetus is particularly sensitive. However, fish is the primary dietary source for docosahexaenoic acid (DHA), an n-3 fatty acid essential for fetal neurodevelopment. Most pregnant women do not consume the recommended 200mg/d of DHA. Concern exists that recommendations for greater fish consumption during pregnancy may result in MeHg exposure above the EPA reference dose (RfD) of 0.1 mcg/kg body weight/day.

Methods: We recruited 61 pregnant women at 12-22 weeks gestation who consumed <=2 fish servings/mo, and we randomized them to 3 arms: education on the health benefits of low-mercury/high-DHA fish including a brochure, wallet card, and weekly emails (E); education + grocery store gift cards worth $10/wk to purchase fish (E+); or control messages about healthful diet not focused on fish. At baseline and 12-week follow-up we queried intake of 31 fish and shellfish in the past month. We estimated DHA intake using the USDA nutrient database, and intake of MeHg using published reference data. Among the 51 women who have completed follow-up visits to date, we performed linear regression analyses comparing change in intake of fish, DHA from fish, and MeHg from fish among the 3 groups.

Results: At recruitment, participant characteristics and mean (range) intakes of fish [1.1 (0-2) sv/mo], DHA [90 (0-522) mg/d], and MeHg [0.03 (0-0.13) mcg/kg/d] from fish were similar in all 3 arms. From baseline to follow-up, participants reported increased intake of both fish [E 3.7 oz/wk (95% CI: -0.7, 8.2), E+ 5.5 oz/wk (1.0, 9.9), p=.047] and DHA [E 83 mg/d (13, 153), E+ 156 mg/d (86, 226), p=0.0002], compared with controls. Change in intake of MeHg did not differ in intervention vs. control arms [E -0.01 mcg/kg/d (-0.03, 0.02), E+ 0.02 mcg/kg/d (-0.02, 0.04), p=0.50]. At follow-up more intervention women consumed >= 200mg/d of DHA (E 31%, E+ 50%, control 0%, p=0.001). Few women had estimated MeHg intake above the RfD at baseline (n=4, 8%) or follow-up (n=3, 6%). Assays of biomarkers for both DHA and MeHg are in progress.

Conclusion: An educational intervention among pregnant women increased self-reported consumption of fish and DHA without an increase in MeHg intake. Future studies are needed to determine intervention effects on pregnancy outcomes.

MG14-P12 — 11:00-12:00 and 17:30-18:30
EFFECTS ON PROLACTIN (PRL) ON CYTOTOXITY INDUCED BY METHYLMERCURY IN HUMAN LYMPHOCYTES AND HUMAN PROMYELOCYTIC LEUKEMIA CELL HL60, BOTH IN VITRO.
Authors: SILVA-PEREIRA, Liz Carmem L.C.1, BURBANO, Rommel Rodriguez R.R.2
(1) IFPA Federal Institute of Educacion, Science and Tecnology Pará Brazil, lizcarme@hotmail.com; (2) UFPA Federal University of Pará Brazil.

Mercury is a xenobiotic metal that is a highly deleterious environmental pollutant. The biotransformation of mercury chloride (HgCl2) into methylmercury chloride (CH3HgCl) in aquatic environments is well-known and humans are exposed by consumption of contaminated fish, shellfish and algae. Methylmercury has been an environmental concern to public health and regulatory agencies for over 50 years because of its neurotoxicity. Its association with nervous system toxicity in adults and infants near Minamata Bay, Japan, in the 1950’s initiated environmental health research inquiries that continue to this day. The objective of the present study was to determine the changes induced in vitro by two mercury compounds (HgCl2 and CH3HgCl) in cultured human lymphocytes; and after that evaluate Prolactina’s action (PRL) on the organomercurial (CH3HgCl) activity in human lymphocytes and human promyelocytic leukemia cell HL60, both in vitro. The cultures were incubated to 37°C for 48 h for both biological systems and the treatments were realize 9h after the beginning stimulating cells. A significant increase (P < 0.05) in the relative frequency of chromosome aberrations was observed for all concentrations of CH3HgCl (1, 10, 100, and 1000 µg/l) when compared to control, whether alone or in an evident sinergistic combination with HgCl2. In the second experimental block, CH3HgCl when alone treaty (50, 100, 500 and 1000 µM) it was cytotoxic also, however its reduced when treaty together with PRL (1,10 and 100 nM). The frequency of polyploid cells was also significantly increased (P < 0.05) when compared to control after exposure to all concentrations of CH3HgCl alone or in combination with HgCl2, however reduced been in PRL presence. CH3HgCl significantly decreased (P < 0.05) the mitotic index at 100 and 1000 µg/l alone, and at 1, 10, 100, and 1000 µg/l when combined with HgCl2, showing a synergistic cytotoxic effect, the same results presented in the second experimental block too, however the PRL presents a protector effect over that. Our data showed that low concentrations of CH3HgCl might be cytotoxic/genotoxic and the PRL is a potent antimutagenic agent in this biological systems.

MG14-P13 — 11:00-12:00 and 17:30-18:30
EVENT-RELATED BIOMARKERS OF ELEMENTAL MERCURY EXPOSURE.
Author: HERBRANDSON, Carl1
(1)Minnesota Department of Health, carl.herbrandson@state.mn.us

While it is rare that elemental mercury exposure incidents lead to measurements of elevated mercury exposure, parents almost always want their child tested during a mercury exposure incident. A lack of understanding about the behavior of elemental mercury in the body can create confusion when evaluating measures of exposure. Two incidents demonstrating the utility of different measures of individual mercury vapor exposure in biological specimens will be discussed:

  • A seven year old boy was hospitalized with leg pain, tachycardia, hypertension, excessive sweating, weight loss, and skin rash. Results from heavy metals urine analyses suggested a significant mercury exposure. The child was diagnosed with acrodynia (a severe childhood disease resulting from mercury poisoning). Environmental sampling of the child’s home disclosed a small old mercury spill in the carpet where the boy watched television. The spill resulted in high, localized mercury vapor concentrations and a longterm exposure. Exposure of this child, and not his younger siblings, was likely caused by different behaviors.
  • Eighteen children were exposed to a large amount of elemental mercury for a relatively short period of time. Samples of blood, urine and/or exhaled air were taken from 14 individuals. Data were used to model likely exposures. Mercury vapor in exhaled air was found to be a useful marker of incident exposure and re-exposure.

A simple mercury inhalation exposure model is presented, along with a discussion of biomarker levels following different types of mercury exposure.

MG14-P14 — 11:00-12:00 and 17:30-18:30
EFFECTING FACTORS TO MERCURY LEVEL IN SCHOOL CHILDREN IN THE SOUTHEASTERN REGION, KOREA
Authors: KIM, Dae-Seon1, AHN, Seung Chul2, CHUNG, Hee-Ung 2, KWON, Young Min 2, KIM, Sam-Cwan1
(1) National Institute of Environmental Research, kimds4@korea.kr; (2) National Institute of Environmental Research ;

Objectives:
We conducted this project to get information of mercury exposure level in school children and to find out related factors which effect on their mercury levels in the areas of high mercury exposure to adults from 2007 Korea National Environmental Health Survey(KNEHS). The final purpose was based on the protection of children’s health.

Method:
Totally, 1,097 students among grade 4 to 6 in 19 elementary schools in Kunwee county, Yeongcheon-city, Pohang-city, and Unlsan-metropolitan city participated in this study from June to September 2010. Whole blood, urine and hair were collected to measure total mercury with health check up. Questionnaires, computerized neurobehavioral test, personality test, dental examination, chromatoptometry and posturography test were applied. Parents completed questionnaires including socioeconomic status, living circumstance, dietary habit for their children. Total mercury concentrations were measured using the gold-amalgam collection methods.

Results & Discussion:
The mean value of total mercury was 2.70µg/L in blood samples, 2.25µg/g-creat. in urine samples and 1.04µg/g in hair samples. Blood mercury was slightly higher than the value of 2006 mercury survey for elementary school children project(p<0.01). On the otherhand, adults in these areas showed about 9-10 times of higher blood mercury level than the mean value of 2007 KNEHS. However, 0.3% and 4.5% of participants were exceeded the blood mercury reference by CHBMII(15µg/L) and EPA(5.8µg/L), respectively. 0.4% and 6.1% of participants were exceeded the urine mercury reference by CHBMII(20µg/L) and EPA(5.8µg/L), respectively. In the questionnaire survey, significant associations were found between residence period in the study areas and blood mercury, among mercury levels in blood, urine and hair samples and risk factors such as fish preference and intake degree. Mercury in biological samples were increased with frequencies of fish intakes, especially, with recent intake and yearly intake chances of shark meat. Father’s education level, number of amalgam treated side, and participation in the performance of ancestral rites also showed significant relations with mercury level in biological samples. Total mercury concentrations were divided into two groups, upper and lower concentration group, based on the median value. Significant differences were found between delinquency, family relationships, hyperactivity and urine mercury. In addition, significant associations were found between color matching and blood mercury, and between dyschromatopsia related factors and urine and blood mercury.

MG14-P15 — 11:00-12:00 and 17:30-18:30
WHY RESIDENTS IN SEOKSAN SHOW HIGH BLOOD MERCURY ?
Authors: KIM, Dae-Seon1, CHUNG, Hee-Ung 2, KWON, Young Min 2, YU, Seung Do 3
(1) National Institute of Environmental Research, kimds4@korea.kr; (2) National Institute of Environmental Research, Korea; (3) National Institute of Environmental Research, Korea .

According to Korea National Environmental Health Survey(KNEHS) in 2007, it showed very high blood mercury level in adults in Gyeongsangdo province, Southeastern part of Korean peninsula(Seoksan, Kunwee county 29.6µg/L, Shinnyeong, Yeongcheon city 26.7µg/L), in the meanwhile, the national mean of blood mercury was 3.8µg/L in geometric mean and 5.54µg/L in arithmetic mean in same project in 2007. They have a custom to intake shark meat through ancestral rites in special days such as new years day, Chuseok day(the harvest festival on the 15th of August by the lunar calendar) and the ceremonies of private memorial rites. Cooking types of shark meat are mostly roast and spit roast types. In these context, dietary intake of shark meat was assumed to be a main source of mercury exposure. This study was conducted to monitor mercury exposure and to confirm the exposure factor for the protection of residents’ health in Seoksan. Seoksan had totally 175 registered residents in 2009 governmental statistics, however, actual residents were around 120 residents including 13 primary students in 2010. The survey was conducted two times in 2010, before and after Chuseok festival day on September 22. The first survey was on August 9-11 and the second was September 24-26 for whole residents at those times. The mean values of blood mercury from total population were 6.58µg/L in the first and 10.51µg/L in the second survey. In the group who answered ‘keeping dietary habit of shark meat’ and showd 6.4µg/L in the first survey, residents who ate shark meat during Chuseok festival showed 11.2µg/L, in the meanwhile, residents who didn’t eat shark meat during same period showed 4.5µg/L in blood mercury concentration. In the group of ’no dietary habit of shark meat’ who showd 5.29µg/L in the first survey, residents who ate shark meat during Chuseok showed 10.0µg/L, and residents who didn’t eat shark meat during same period showed 4.0µg/L in blood mercury concentration. The number of participation chance to ancestral rites showed correlation with blood mercury concentration (p<0.01). However, total mercury was 1.035mg/kg in Mako shark and 0.901mg/kg in Hammerhead shark, which were collected in the nearest market from Seoksan in 2010. On the other hand, 1.4~2.2mg/kg of methyl mercury in shark meat were reported in other survey in 2010. It is recommended to make a guideline for dietary intake of shark meat for residents in this area.

MG14-P16 — 11:00-12:00 and 17:30-18:30
MERCURY EXPOSURE AND COLOR VISION IMPAIRMENT IN SCHOOLCHILDREN
Authors: LEE, Eun-Hee 1, OH, Hyun Jin 2, CHUNG, Hee-Ung 3, AHN, Seung Chul 3, KIM, Dae-Seon 3
(1) Department of Health Science, Far East University, Korea; (2) Department of Optometry, Masan University, Korea; (3) National Institute of Environmental Research, Korea ;

Objectives:
This study was designed as a cross sectional study in order to find out the evidence of the relationship between mercury exposure and color vision impairment.

Methods:
A total of 601 children (3rd to 6th grade) attending 9 elementary school of some area in Korea participated in this study. Total mercury in blood, urine and hair samples from school children was analysed using Gold amalgam method. Color vision was assessed with Isihara test and Han’s 15 Hue test and Lanthony D-15 desaturated test. In visual effect from mercury exposure, inclusion criteria were Sellen(VA 20/33) and Hans(VA 0.6) or better and absence of known ophthalmologic pathologies. 516 of total 601 subjects were assessed for color vision impairment with mercury exposure to the exclusion of 17 congenital impairments by Ishihara test and 76 subjects less than VA 0.6. Acquired color vision impairment was detected from 72 subjects.

Results & Discussion:
The geometric mean of mercury of acquired color vision impairment group were 2.46 µg/L in blood, 1.00 µg/g in hair, and were significantly higher than those from normal group, which were 2.23 µg/L in blood, and 0.76 µg/g in hair, respectively(p<0.05). On the other hand, the geometric mean of urine mercury of acquired color vision impairment group was 1.73 µg/g creatinine, and was higher than that from normal group, which was 1.40 µg/g creatinine, but did not show statistical significance. Total subjects were divided into two groups, upper and lower mercury concentration group, based on the median value of total mercury concentrations. The frequency of color vision abnormality in upper mercury concentration group was significantly higher than that of low concentration group in hair and urine (p<0.01). The frequency of blue-yellow and complex color vision impairment in upper mercury concentration group was significantly higher than that of low concentration group in hair (p<0.05). Authors found some clues that mercury exposure may influence color vision from this study and convinced visual test could be an indicator of mercury exposure.

MG14-P17 — 11:00-12:00 and 17:30-18:30
ESTIMATED INTAKE LEVELS FOR FINNISH CHILDREN OF METHYLMERCURY FROM FISH
Author: LEINO, Olli1
(1) THL, olli.leino@thl.fi

Methylmercury (MeHg), a well known neurotoxic agent, biomagnifies in aquatic food webs into predatory fish. Generally, consumption of MeHg contaminated fish is the most significant environmental source of mercury exposure in humans. For several reasons, infants and children are more susceptible to adverse effects of contaminant exposure than adults. MeHg intake data in children is often sparse, indeed this is the first study conducted in Finland. We examined gender-specific fish consumption of all species most commonly consumed by Finnish children aged 1 to 6 years, determined total mercury concentrations in the fish, and derived age-specific MeHg intakes in the children. The MeHg intakes were compared to the tolerable daily intakes set by international expert bodies, and the proportion of the population to exceed them was studied. The intakes were described as probability distributions. The data used corresponds to years 2002-2005. The daily intake of MeHg ranged from zero to 0.33 µg/kg bw. The strictest reference value 0.1 µg/kg bw/d for MeHg proposed by U.S.EPA was exceeded by 1-15 % of the study population. The less strict FAO/WHO JECFA provisional tolerable weekly intake of 1.6 µg/kg bw was exceeded by 1% of boys and 2.5% of girls aged six years. Intakes by girls were higher than by boys at the age of one, whereas for three-year olds they were the opposite. The highest intakes were observed for 6-year-old boys and girls. As generally recognized, we found that MeHg concentration in fish is strongly related to certain fish species, and the estimated MeHg intakes varied remarkably between individual and age. The results emphasize the need for evaluating children’s MeHg exposure.

MG14-P18 — 11:00-12:00 and 17:30-18:30
RISK PERCEPTION OF METHYLMERCURY IN FISHERY PRODUCTS AMONG PARTICIPANTS OF HAIR MERCURY ANALYSIS PROGRAM IN JAPAN
Authors: HACHIYA, Noriiyuki1, YASUTAKE, Akira2
(1) National Institute forMinamata Disease, hachiya@nimd.go.jp; (2) .

A hair mercury analysis program was provided as a risk communication tool regarding low-level methylmercury exposure for visitors to environmental events held at six different sites across Japan from 2006 to 2008. The risk perception of the chemical was surveyed among 855 participants who answered a questionnaire on the time of hair sampling. The acceptance of one’s own hair mercury level was analyzed among 335 participants who responded to a second questionnaire after notification of their total mercury concentration. The analytical result was provided along with information on reference levels including population averages and concentrations corresponding to PTWIs of Japan (2.8 µg/g for pregnant women, and 5.0 µg/g for adults). The geometric mean was 1.93 µg/g in females and 2.55 µg/g in males. The concentration was significantly associated with fish intake especially of tuna. More than half of the participants, i.e. 57.4% in females and 52.3% in males, knew Fish Intake Advisory for Pregnant Women of the Ministry of Health, Labour and Welfare, Japan. Almost half, i.e. 41.7% in females and 50.2% in males, recognized that every commercial fish contains trace amounts of methylmercury regardless of the fishing site. The frequency of participants who felt any anxiety about her/his mercury level was 31.5% in females and 15.7% in males. The increase in hair mercury level resulted in decrease of reassurance on the own level but only a partial increase in anxiety. The cumulative frequency of the anxiety versus mercury concentration indicated that the frequency reached half of the total frequency at hair mercury concentrations of 2.0 µg/g in females and 2.6 µg/g in males, which are similar to the population averages. These observations coincide with the assumption that the occurrence of anxiety was mainly dependent on comparison with the concentration of the population average, rather than comparison with the safety standard levels.

MG14-P19 — 11:00-12:00 and 17:30-18:30
A RETROSPECTIVE COHORT STUDY ON THE EFFECTS OF PRENATAL AND POSTNATAL METHYL MERCURY EXPOSURE ? A SURVEY AFTER 40 YEARS IN NIIGATA, JAPAN
Authors: NAKADAIRA, Hiroto1, SAITO, Hisashi2, TAKAKAMO, S2, URASAKI, Sadako2, RAITA, M2, KAGOSHIMA, J2, KAWAI, S2
(1) Niigata Seiryo Univ., nkdr@mail.n-seiryo.ac.jp; (2) Kido Hospital;

Purpose:
It is apparent that a bigger influence of the methyl mercury contamination is seen in children and the fetus more than adults. We investigated what kind of influence the people who received the methyl mercury exposure in their prenatal and postnatal stage in the Agano River basin.

Method:
As for the exposure group, there were 15 cases whose mother’s hair mercury level was 50 ppm and more and 22 cases having from 10 ppm to 50 ppm. The total number of the exposure group was 37 people, while the number of the control group was 47 people. For the control group we chose people of the same generation who hadn’t eaten the fish of the Agano River. We surveyed them by investigation of the subjects and by interviewing their mothers. For continuous data, t-test was used and the chi square test was used for categorical data. All statistical tests were two-tailed. The significance level was set at p<0.05.

Results and Conclusions
As for the investigation results, the following findings and signs were significantly evident in the exposed group than the control group.

  1. The birth weight was a little less in the exposed group than the control group.
  2. Walking was unsteady in their childhood in dark places.
  3. They fell over easily, couldn’t talk well and had blurred vision.
  4. They also had awkward use of chopsticks, numbness of the limbs and easily cramped muscles.
  5. They suffered from headaches and the stomachaches
    (6)They had difficulty adapting to group life.
  6. Sometimes, they had tremors in their limbs.
    (8)In childhood they often had difficulty in doing up buttons.
  7. In childhood they often had feelings of irritation and insomnia.
    A great variety of influence was confirmed in the people who were exposed to the methyl mercury in their prenatal and postnatal stage.

MG14-P20 — 11:00-12:00 and 17:30-18:30
FISH CONSUMPTION AND MERCURY EXPOSURE IN RIVERINES OF RIO MAMORE, WESTERN AMAZON
Authors: MARQUES, Rejane C1, DÓREA, José G2, LEÃO, Renata S1, MOREIRA, Maria de Fátima R3, FRANCO, Tainara F4, MALM, Olaf1
(1) Universidade Federal do Rio de Janeiro, rejanecmarques@globo.com; (2) Universidade de Brasília; (3) Fundação Oswaldo Cruz; (4) Universidade Federal de Rondonia;

Mercury levels in hair are correlated to eating habits, particularly fish consumption by riverines populations with a large contingent of traditional fishing families. A cross-sectional study was performed to assess fish mercury (Hg) exposure among 239 (n=125, female; n= 114, male) riverines living along the banks of the Rio Mamore, Rondonia State, Brazil. Summary clinical examination, socio-economic variables, food consumption inventory and total hair-Hg concentrations were measure. Hair Hg was analyzed by Cold Vapor Atomic Absorption Spectrometry. The mean frequency of fish consumption is high (= 4.09 per week) with 64 % consuming fish >2 fishmeal/d. The values of hair mercury were well above the level set by World Health Organization for an adult population (10 µg/g). Mean hair-Hg 13.29µg/g (range 0.23-117.66). Young children (< 1 years old) still breastfeeding showed a mean hair-Hg of 2.55 µg/g, and children from 1 to 5 years old had a mean Hg of 5.39 µg/g (range = 0.23 – 35.59). Hair-Hg concentrations in women (18.57 µg/g) were significantly higher (t = 3.15; p < 0.01) than in men (16.95 µg/g). These results confirm that nutrition transition due to human occupation of the Western Amazonia still maintains the centrality of fish for the traditional riverine populations.

MG14-P21 — 11:00-12:00 and 17:30-18:30
MERCURY POLLUTION AT THE AAMJIWNAANG FIRST NATION: ECOLOGICAL AND HUMAN EXPOSURES
Authors: CRYDERMAN, Diana K1, LETOURNEAU, Lisa1, MILLER, Fiona2, JOHNSTON, Sherilyn 3, BASU, Niladri1
(1) University of Michigan, School of Public Health, dkcryder@umich.edu; (2) University of Michigan, Center for Human Growth and Development; (3) Aamjiwnaang First Nation Environmental Department;

The Aamjiwnaang First Nations Reserve is located along the St. Clair River in Southern Ontario among a highly industrialized petrochemical center that is designated an Area of Concern that spans the US/Canadian border. In 2008, 2401 kg of mercury were released by facilities within in 25 km radius of the Reserve. For several decades, methylmercury concentrations in sediments have exceeded lowest effect levels for invertebrate health and fish consumption advisories have been chronic in the region. Here we assess mercury contamination at the Aamjiwnaang First Nations Reserve by studying both ecological and human samples. Local stream sediment and soil from both on and off Reserve were analyzed for total mercury content. Hair from Aamjiwnaang community members was analyzed for mercury to address human body burdens. Soil collected from 28 playgrounds in the area and 23 local stream sites showed mercury concentrations ranging from 2 to 100 ppb and from 5 to upwards of 650 ppb, respectively. Notably, a few of these sites had soil mercury levels that exceeded the United States National Oceanic and Atmospheric Administration Ecological Soil Screening Level guideline for plant and invertebrate health. Hair collected from 8 mothers and their children living on the Reserve contained mercury in the range of 0.008 to 0.277 µg/g. Hair mercury levels were higher in mothers than children, but overall concentrations were below the United States Environmental Protection Agency guideline values of 1ug/g. This data suggests that mercury continues to contaminate the Aamjiwnaang landscape but that levels in human residents may not be of health concern.

MG14-P22 — 11:00-12:00 and 17:30-18:30
OCCUPATIONAL EXPOSURE TO MERCURY IN A DENTAL CARE UNIT
Authors: MOREIRA, Maria de Fátima Ramos1, JESUS, Leda Diva Freitas de Jesus1, MARINHA, Marden Marinha1, DUARTE, Nei Santos Duarte1, BAPTISTA, Fernanda Baptista1, GOMES, Regina Aderne Gomes1
(1) Oswaldo Cruz Foundation, fmoreira@ensp.fiocruz.br

The aim of this study was to assess the occupational exposure to mercury in dentistry. A group exposed to mercury by handling dental amalgam in a dental care unit (DCU) was compared to another group who did not use the metal. Air samples were collected with active and passive samplers. Participants donated urine samples. Average concentrations in urine were 1.78 ± 0.67 for the exposed workers, while it was only 0.92 ± 0.32 µg L-1 in the controls. Average concentrations in impingers were 0.36 ± 0.04 in the DCU and 0.19 ± 0.05 µg m-3 in the controls. Passive samplers showed levels below the detection limit. The comparison between exposed and nonexposed groups showed a statistically significant difference according to the Student’s t test and 95% of confidence for both urine and air samples collected with impingers. The Spearman correlation coefficient showed positive associations between Hg levels in impingers and urine, in urine and sex and in urine and exposure time. Mercury contaminated all the people who attended that workplace.

MG14-P23 — 11:00-12:00 and 17:30-18:30
LOW-LEVEL MATERNAL METHYLMERCURY EXPOSURE THROUGH RICE INGESTION AND IMPLICATIONS FOR OFFSPRING HEALTH
Authors: ROTHENBERG, Sarah1, FENG, Xinbin1, LI, Ping1
(1) Institute of Geochemistry, Guiyang, China, rothenberg.sarah@gmail.com

Fish consumption is considered the primary pathway for methylmercury (MeHg) exposure; however, MeHg exposure also occurs through rice ingestion. Rice is grown in an aquatic environment and although documented MeHg concentrations in rice are lower compared to fish tissue, human exposures exceed international guidelines in some regions in China where rice is a staple food and rice MeHg levels are elevated. Studies concerning MeHg and children’s neurodevelopment should also include populations where maternal MeHg exposure occurs through ingestion of rice. Rice does not contain long-chain polyunsaturated fatty acids (LCPUFA), which benefit neurodevelopment and are associated with confounding developmental outcomes in offspring. The tolerable level of MeHg associated with adverse neurodevelopmental effects will likely be lower when LCPUFA are not simultaneously ingested, since LCPUFA offset or ameliorate the harmful neurotoxic effects from MeHg. Rice is also a staple food for more than half the world’s population; therefore, it is critical to investigate the potential health risks of maternal ingestion of rice to the developing fetus, the most susceptible population to the deleterious effects of MeHg. This review covers mercury cycling in rice paddies, rice MeHg levels, micronutrients in polished white rice, and other potential confounders of concern that may help explain results in a study concerning maternal MeHg exposure through rice ingestion and offspring neurodevelopment.

MG14-P24 — 11:00-12:00 and 17:30-18:30
QUANTIFICATION OF ENVIRONMENTAL RISKS ASSOCIATED WITH DENTAL AMALGAM DISPOSAL IN NATIONS WITH DEVELOPING ECONOMIES
Authors: ROTHENBERG, Sarah1, KATZ, Ralph1
(1) NYU College of Dentistry, Dept of Epidemiology and Health Promotion, rothenberg.sarah@gmail.com

Dental amalgam has been used for more than 150 years to repair cavities in teeth, and is approximately 50% elemental Hg (Hgo), a known toxic substance. A number of recent studies, including the New England Children’s Amalgam Trial (Bellinger et al., 2006. JAMA 295, 1775-1783) and the Casa Pia Study of the Health Effects of Dental Amalgams in Children (DeRouen et al., 2006. JAMA 295, 1784-1792), have reported no causal relationship between the placement of dental amalgam fillings and adverse cognitive outcomes in children. However, environmental risks associated with the disposal of amalgam is an environmental concern requiring attention. Dental waste collected from the chair side and from dental wastewater contained total Hg (HgT) and methylmercury (MeHg) concentrations ranging from 1800-2400 ug/L and 0.90-27 ug/L, respectively, both of which were 2-3 orders higher than highly contaminated industrial sites (Stone et al., 2003. Dental Materials 19, 675-679). While wastewater treatment standards in developed countries may reduce the environmental risk by using advanced treatment methods, in nations with developing economies, the infrastructure to separate and treat wastewater may not exist or may be poorly funded, and runoff may be a significant source of inorganic Hg(II) and MeHg to the surrounding watershed. Untreated dental waste may lead to elevation and biomagnification of MeHg in the aquatic food, resulting in serious harm to human health. The costs and benefits of using dental amalgam are considered for nations with developing economies, where dental care is increasing and the risk to the environment is highest.

MG14-P25 — 11:00-12:00 and 17:30-18:30
SUITABILITY OF BIOMARKERS OF LOW-TO-MEDIUM MERCURY EXPOSURE IN PREGNANT WOMEN
Authors: TRATNIK, Janja1, MRAK, Irena1, BEGIC, Irena1, MIKLAVCIC, Ana1, PLANINSEK, Petra1, CUDERMAN, Petra1, KRSNIK, Mladen2, BARBONE, Fabio3, MARIUZ, Marika3, SOFIANOU, Katia4, SPIRIC, Zdravko5, HORVAT, Milena1
(1) Jozef Stefan Institute, Ljubljana, Slovenia, janja.tratnik@ijs.si; (2) University Medical Centre, Ljubljana, Slovenia; (3) University of Udine, Udine, Italy; (4) Institute of Child Health, Athens, Greece; (5) Institute for Applied Ecology, Zagreb, Croatia;

Based on the results obtained in a preliminary and a large-scale study as part of the PHIME project (EU 6th framework programme), suitability of selected biomarkers of low-to-moderate mercury (Hg) exposure was evaluated. In the preliminary study, MeHg (methyl mercury) and THg (total mercury) were determined in maternal blood, umbilical cord blood, placenta, meconium, maternal scalp and pubic hair collected from 28 mother-child pairs. In the following longitudinal cohort study, THg and MeHg were determined in maternal scalp hair, maternal blood, umbilical cord blood and breast milk from 618 mother-child pairs from Mediterranean region. Both studies showed variable proportion of Hg as MeHg in maternal and cord blood (12 to 100 %) and scalp hair (10 to 100 %), and highly variable inter-individual hair-to-blood MeHg ratio (67 to 760). Nevertheless, the median values for proportion of Hg as MeHg in cord blood and hair were 97 and 99 %, respectively. Maternal scalp hair MeHg was associated more strongly with blood than pubic hair MeHg (r=0.621, p=0.008 and r=0.468, p=0.058, respectively). The significance of placenta as an indicator of MeHg or inorganic Hg exposure is questionable, while meconium was found to indicate MeHg exposure to a certain extent, although the negligible proportion of Hg present as MeHg in meconium indicated possible demethylation of MeHg in the foetus. In contrast to blood and hair, very weak association between THg and MeHg was observed in breast milk (r=0.138, p=0.025), while the proportion of Hg as MeHg was negatively associated with THg (r=-0.305, p<0.001). In all conducted studies, Hg in blood and hair was positively and significantly associated with the frequency of fish consumption, while THg in urine was positively and significantly associated with the number of dental amalgam fillings. Hg in breast milk was more strongly and significantly associated with the number of amalgam fillings than with the frequency of fish consumption. Although Hg in blood is the most suitable biomarker of inorganic Hg or MeHg exposure, when speciation analysis is performed, THg in hair was found to be sufficient as an approximate indicator of exposure to MeHg resulting from fish consumption and THg in urine as a good indicator of exposure to inorganic Hg from dental amalgam fillings. Breast milk THg was observed to indicate mainly inorganic Hg exposure.

MG14-P26 — 11:00-12:00 and 17:30-18:30
AN EVALUATION OF THE POTENTIAL FOR JOINT TOXICITY AND CUMULATIVE RISK FOLLOWING COMBINED EXPOSURE TO MERCURY VAPOUR, METHYLMERCURY AND LEAD.
Authors: PURTILL, Colleen1, RICHARDSON, Mark1, ALLARD, David1, DOUMA, Stephanie1, GRAVIERE, Julien1, WILSON, Ross1
(1) SNC-Lavalin Environment, colleen.purtill@snclavalin.com

Concurrent exposure to mercury vapour (Hg0), methylmercury (MeHg) and lead (Pb) is occurring in the US population. Hg and Pb were #3 and #2, respectively, on the 2007 list of substances at Superfund Sites, ranked according to potential threat to human health. Evidence for concurrent exposure to Hg0, MeHg and Pb was provided in the 2003-2004 National Health and Nutrition Examination Suvey (NHANES) conducted under the US National Centre for Health Statistics (NCHS). These data indicated the simultaneous presence of Hg in urine, MeHg and inorganic Hg in blood, and Pb in blood for a total of 1,008 survey participants. Using population weighting factors provided by the NCHS these 1,008 participants represented over 120 million members of the US population, which suggests approximately one-third of Americans were concurrently exposed to Pb, MeHg and Hg0.

A detailed review of the toxicokinetic and toxicodynamic characteristics of these substances was conducted. This review focused on the potential for joint toxicity following combined exposures to Hg0, MeHg, and Pb. Similarities were observed for the absorption, distribution, transformation and storage characteristics for these substances. Similar targets for neurological effects were also identified for combinations of these substances, including: stimulus evoked CNS and PNS activity; neurotransmitter release; and neuronal damage/apoptosis as a result of oxidative stress (generation of reactive oxygen and nitrogen species), alterations in calcium homeostasis, alterations in excitatory amino acids (glutamate), and lipid peroxidation. Several studies reported that both MeHg and Pb adversely affected significant stages of neurodevelopment, including neuronal differentiation, synaptogenesis and planned apoptosis.

Given the ubiquitous nature of Hg0, MeHg and Pb and indications of potential joint toxicity, guidance provided by the ATSDR for the assessment of chemical mixtures was used to determine potential risks associated with concurrent US exposure (i.e., NHANES data) to these metals. Hazard Index values, representing the sum of Hazard Quotients for each substance, >1 were estimated for over 120 million Americans. The Hazard Index should not exceed a value of 1 to be reasonably guaranteed of public health protection. It is noted that these risk estimates were based on measured levels of Hg and Pb in the urine and/or blood and therefore the margin of safety generally afforded by the conservative nature of exposure assumptions in human health risk assessment does not apply to these risk estimates.

MG14-P27 — 11:00-12:00 and 17:30-18:30
HAIR MERCURY LEVELS IN THE 19TH CENTURY: CAN MOURNING JEWELRY PROVIDE VALUABLE INFORMATION
Authors: ZAREBA, Grazyna1, LANGDON, Margaret1, OSINSKI, Anthony W. 1, SPIGELMAN, Zachary2
(1)Department of Environmental Medicine, University of Rochester Medical Center, Rochester NY, grazyna_zareba@urmc.rochester.edu; (2) Harvard University School of Medicine, Boston MA.

Several medical historical sources describe widespread use in the 19th century of both metallic mercury (Hg) in the form of the Blue Mass pill, and inorganic Hg as calomel for therapeutic purposes. Although hair has been a well established indicator of methyl mercury exposure in several population studies there are reports of elevated hair Hg levels during accidental or suicidal use of other forms. Mourning jewelry containing hair of beloved ones was popular in America during the Civil War era. In order to study mean Hg hair levels in this time period in American history, mourning jewelry from mid 19th century was purchased from different antique stores in America. According to manuals for hair jewelry making, hair preparation consisted of boiling hair for 15-20 min with baking soda and occasionally mounting braided hair to a fabric or paper background. Out of 13 collected samples, only 6 met criteria for analysis: the hair samples had no access to open air (under glass cover) and no visible contamination with soil. Analysis of total and inorganic Hg using cold vapor atomic absorption spectroscopy was performed in the Mercury Laboratory at the University of Rochester. All analyses were performed in a blinded manner, hair 397 was used as a standard during each analysis. Quality assurance was performed using the Mercury in Hair Interlaboratory Comparison Program (Ottawa, Canada). The total Hg concentrations were 18.3 +/- 4.57 ppm (mean +/- SE), of which inorganic Hg was 79.6 +/-6.92% of the sample. The observed Hg hair levels were significantly higher than today’s mean population levels. However, they were similar or higher to previously reported Hg hair concentrations during accidental or suicidal use of metallic or inorganic mercury. The washing procedures of hair samples demonstrated only minimal Hg removal from hair, suggesting strong Hg binding to the hair shaft. In conclusion, this study, as part of larger studies on Hg human exposure during the Civil War era, demonstrated elevated Hg hair concentrations in humans suggesting increased exposure to different forms of inorganic mercury, possibly above today’s acceptable mercury levels. These results as well as future analyses may contribute to better understanding several neurological symptoms and maladies described in the 19th century.

MG14-P28 — 11:00-12:00 and 17:30-18:30
MERCURY EXPOSURE IN RIVERINES OF RIO MADEIRA
Authors: MARQUES, Rejane C1, LEAO, Renata S1, BRANDAO, Katiane G2, MIRANDA, Aldecira P2, MOREIRA, Maria de Fatima R3, MALM, Olaf1
(1) Universidade Federal do Rio de Janeiro, rejanecmarques@globo.com; (2) Universidade Federal de Rondonia; (3) Fundação Oswaldo Cruz;

Mercury (Hg) is present in the Amazonian aquatic environments from both natural and anthropogenic sources. Consequently, riverines populations in Amazonia are exposed to mercury because of their intense fish consumption. This study evaluates total Hg levels in hair of 142 Amazonian riverines living along the banks of the Rio Madeira, Rondonia State, Brazil. Individuals answered a questionnaire where socio-economical status and clinical variables were evaluated. Hair samples were taken from the occipital region, and Hg-T was analyzed by Cold Vapor Atomic Absorption Spectrometry. 61% (n=86) were female and 39% were masculine (n= 56). The mean frequency of fish consumption were 3.98 per week, with 65 % consuming fish >2 fishmeal/d. The values of hair mercury were well above the level set by World Health Organization for an adult population (10 µg/g). Mean hair-Hg 13.76 µg/g (range 0.92 – 153.72). Young children (< 1 years old) still breastfeeding showed a mean hair-Hg of 3.92 µg/g, and children from one to 5 years old had a mean Hg of 5.39 µg/g (range = 0.92 – 15.42). Hair-Hg concentrations in men (15.37 µg/g; range = 1.02 – 153.72) were significantly higher than in women (12.71 µg/g; range = 0.92 – 77.76). It remains difficult to conclude on the Public Health implication of mercury exposure in this context.

MG14-P29 — 11:00-12:00 and 17:30-18:30
MERCURY IN HAIR AND CLINICAL SYMPTOMS IN RIVERINE COMMUNITIES OF THE AMAZON
Author: MIRANDA, Antônio Marcos Mota1
(1) Evandro Chagas Institute, marcosmota@iec.pa.gov.br

In the Amazon, the main route of mercury exposure to riverine populations in the Tapajós basin occurs by preferential consumption of fish. Assess groups of elderly in riverine populations from clinical symptoms and their relationship to levels of total mercury in the capillary tissue is an important tool for environmental health surveillance. This study evaluated two groups of elderly. In the first (N=55), consisting of residents of the Barreiras, riverside community on the left margin of the Tapajós river, City of Itaituba, area of mercury environmental exposure due to gold mines located in region. In the second (N=26), consisting of residents of the District of Tabatinga, city of Juruti, identified as control group. We conducted a cross-sectional study from the clinical evaluation and its correlation with mercury levels in hair of each elderly investigated. This human research was approved by the Research Ethics Committee of the Evandro Chagas Institute. The levels of total mercury in hair were measured by CV-AAS. In Tabatinga average mercury in the hair of the elderly population was 6.58 µg/g. In this group, the average women (N=17) was 5.545 µg/g, values lower than the averages recorded in men (N=9) of 8.543 µg/g. Barreiras in the mean mercury in the hair of the elderly was 12.810 µg/g. For this group, women (N=31) showed average levels of 10.276 µg/g while in men (N=24) was at 16.099 µg/g. From these results can be observed that the average of mercury in the population of Barreiras is approximately twice the values found in the population of Tabatinga, confirming that the population of barriers is more exposed to mercury. To evaluate the effects of increased exposure were compared clinical symptoms with average of mercury in hair. Among those elderly people who had lung changes the average of mercury in Tabatinga was 6.739 µg/g while Barreiras was at 10.585 µg/g. For those with cardiovascular average mercury was at 6.739 µg/g while Barreiras was at 10.585 µg/g, showing similarities to the group with pulmonary disorders. Among the groups of elderly who complained of headache clinics the average mercury in the hair was at 6.748 and 13.131 µg/g in Tabatinga and Barreiras, respectively. The highest average mercury in the elderly population of the Barreiras associated with clinical complaints show that this group is more vulnerable than in Tabatinga and that these populations should be expanded monitoring programs and control of environmental health surveillance.

MG14-P31 — 11:00-12:00 and 17:30-18:30
EFFECT OF METHYLMERCURY ON THE EXPRESSION OF AQUAPORIN-4 AND -11 IN THE BRAIN OF THE COMMON MARMOSET
Authors: YAMAMOTO, Megumi1, SASAKI, Masanori1, TAKEYA, Motohiro2, ETO, Komyo3
(1) National Institute for Minamata Disease, yamamoto@nimd.go.jp; (2) Kumamoto University; (3) Jushindai.

In an acute model of methylmercury (MeHg) exposure using common marmosets, the gene expression of aquaporin (AQP)-4 and AQP-11 was examined to understand the relationship between MeHg exposure and AQP expression in the brain. MeHg (1.5 mg Hg/kg body weight/day; p.o.) was given to three marmosets for 14 days, followed by no administration for 14 days. All marmosets of the MeHg-administered group showed slight akinesia immediately before dissection. In the frontal lobe (prefrontal cortex), occipital lobe (around the calcarine sulcus), and cerebellum, the mean total mercury concentration in the MeHg-administrated group (Hg#1, #2, #3) was 26.7, 31.4, and 22.6 µicrogram/g, respectively. Slight apoptosis was observed in the cells of the cerebral cortex of the MeHg-administrated group. Activation of glial fibrillary acidic protein and Iba1 gene expression in the MeHg-administrated group was observed compared with the control group. Immunohistochemistry revealed no apparent difference in AQP-4 expression between the control and MeHg-administrated group. The ratio of AQP-4 mRNA expression between MeHg-administrated marmosets (Hg#1, #2, #3) and the mean of the control (n=3) was 1.3, 1.5, and 1.2; 1.7, 1.9 and 1.5; and 1.5, 1.6 and 1.2 for the frontal lobe, occipital lobe, and cerebellum, respectively. These results indicated activation of AQP-4 mRNA in each location of the brain. When all three brain locations were analyzed altogether, the increase was statistically significant. A significant difference in the expression of AQP-11 mRNA in each location of the brain was not observed between control and MeHg-administrated groups. Brain edema was observed in two (Hg#1, Hg#3) out of three MeHg-administrated marmosets by pathological macro-analysis (white-matter area in the image of the brain section); this indicated that the expression pattern of AQP-4 was not directly correlated with the prevalence of brain edema. These data indicated that MeHg exposure increased AQP-4 expression, but it was difficult to show a clear relationship between the expression of AQP-4 and AQP-11 and brain edema in this model.

MG14-P32 — 11:00-12:00 and 17:30-18:30
THE REEL DEAL: FISHING AND FISH CONSUMPTION PATTERNS IN A SOUTH CAROLINA GULLAH COMMUNITY
Author: ELLIS, Jamelle1
(1)Univeristy of South Carolina, ellis3@email.sc.edu

Gullah people are descendants of African slaves who remained in seclusion on the islands of SC, NC, and FL after the Civil War as self-sufficient fishers. Data on current U.S. fishing and fish consumption patterns are limited. Although numerous studies show the impact of acute methylmercury exposures, the scope of research on the toxicological consequences of chronic low-level mercury exposure from seafood consumption in subsistence communities is relatively narrow. In South Carolina, fish advisories have been placed on many rivers, lakes, and tributaries. Research suggests that subsistence fishers may be more likely to consume larger amounts of fish, potentially exposing them to higher levels of methylmercury. Based on proximity to both freshwater and saltwater, it is unclear whether subsistence fishers catch and consume more freshwater or saltwater fish. Studies conducted along the Savannah River in Georgia suggest differences in fishing and fish consumption between blacks and their white counterparts. It was determined that blacks in this region fished more frequently, consumed more fish meals of larger portions, and ingested more fish per year than whites. The EPA protective criterion for fish consumption is 19 kg/year. Median consumption rates for black males and females were 18.91 and 12.89 kg/year, respectively, and 6.86 and 4.67 kg/year for white males and females. This study will combine the use of fishing and fish consumption surveys with fish tissue analyses of methylmercury along the coast of SC as a preliminary measure for an exposure assessment of the Gullah population.

MG14-P33 — 11:00-12:00 and 17:30-18:30
RELATIONSHIP BETWEEN MERCURY ACCUMULATION AND P53 GENE EXPRESSION IN BREAST CANCER TISSUE
Authors: KHODABANDEH, Saber1, MALEKI, Davood 2, VALEZADEH, Mohammad Amin 2, ESLAMIFAR, Ali 3, POURGHASEM, Jalal2
(1) Tarbiat Modares University, Theran, Iran, surp78@gmail.com; (2) Imam Khomeini Hospital, Urmia, Iran; (3) Pasteur Institute, Tehran, Iran;

High levels of heavy metals such as cadmium, copper and mercury are closely related to tumor growth in cellular systems and cancer. Breast cancer is the major cause of cancer morbidity and mortality in women globally.

In Iran, the breast cancer problem seem more serious because it is significantly increased in last decade (until 10 to 13 %), and also it affects Iranian women at least one decade younger than other countries. p53, tumor suppressor gene, plays an important role in regulating cell cycle and activates growth inhibitory pathways and apoptosis.

In order to determine the correlation between mercury accumulation and breast cancer appearance, we investigated mercury concentration and p53 gene expression in 39 breast cancer biopsies and compared the findings to the levels found in healthy biopsies (control).

We found a highly significant accumulation of mercury (0.2-0.9 µg/g and median=0.7µg/g) in the cancer samples when compared to the control group (p<0.005). Our results also showed that, p53 gene expression was 1.4-4.8 (median 3.4) fold lower in the breast cancer samples in compare to control group.

It is discussed that, mechanisms associated with p53-mediated responses are complex. p53 inhibits trans-activation by binding DNA elements to block DNA replication and also it directly modulates gene expression as a nuclear transcription factor that binds as a homodimer to p53 response elements in regulatory regions of several genes. Previous studies demonstrated that, estrogen hormone can up regulates the gene that cause cancer cell to not die (as p53), and it also reported that, mercury exerts an estrogenic effect through binding to the estrogen receptor that can cause human breast cancer cells to proliferate.

We conclude that, there is a direct relation between mercury concentration among and p53 gene expression in breast cancer tissue and it assume that mercury can cause beast cancer by working as estrogen that can reduce p53 gene expression and finally breast cancer appearance.

MG14-P34 — 11:00-12:00 and 17:30-18:30
COGNITIVE ASSESSMENT OF RIPARIAN SCHOOLCHILDREN FROM THE WESTERN BRAZILIAN AMAZON.
Authors: DA SILVA VIANA JACOBSON, Ludmilla1, DE SOUZA HACON, Sandra 2, MOURÃO, Dennys 2, BASTOS, Wanderley 2, OLIVEIRA, Valéria 2
(1) FIOCRUZ, ludmillaviana@yahoo.com.br; (2) ;

Several studies suggest that exposure to Methilmercury may affect children’s cognitive development. In the Brazilian Amazon riverine population are exposed to MeHg through fish consumption. The aim of this study is to describe the cognitive assessment, and the association between cognitive responses and hair mercury levels above 6µg/g, individual’s characteristics and anemia. This study is part of the Mercury Health Impact Project, in an region where two Hydroelectric Power Plant is been building in Amazon. This is a cross-sectional study with a sample of about 300 riparian schoolchildren, living along the Madeira River, in the Amazon Basin. The cognitive test battery consisted of Raven Colored Progressive Matrices test (RCPM), Rey Complex Figure test (ECF - Copy and Memory trial), and Wechsler Intelligence Scale for Children test (WISC- Symbol and Digit subtests). The tests were performed by psychologists. Hair and blood samples were analyzed. An interview questionnaire was used to collect information on socio demographic characteristics, fish-eating habits, neurological symptoms and other relevant information. The descriptive analysis showed that about 40% of the children presented mercury concentration in hair higher than 6µg/g. The average concentration was 8.5µg/g (95%CI: 7.2 – 9.8), and the maximum value was 92.1µg/g. The blood test showed that, about 35% were anemic The Hg levels in hair were associated with daily fish intake. The results of the tests were aggregated into two categories: intellectually disabled or not. RCPM test indicated that 36% were intellectually disabled and it was associated (p-value<0.10) with gender, age, river bank, school year, failure in school at least once in life, and anemia. A multiple logistic regression model adjusted by school year, estimated an odds ratio of 1.66 (p-value=0.070) for children with hair mercury levels above 6µg/g. The ECF Copy test pointed 63% as intellectually disabled. Variables associated (p-value<0.10) were age, school year, exposure time, diagnostic of malaria, difficult to distinguish colors, difficult to memorize, and fish consumption. A multiple logistic regression model adjusted by age, failure in school, anemia, and smoking in pregnancy, estimated an odds ratio of 3.43 (p-value=0.004) for children with levels of mercury in hair above 6µg/g. WISC Digit test indicated that 12% were intellectually disabled. Variables associated (p-value<0.10) were age, school year, anemia, more agitated than normal, abnormal mental development, irritable, and hair mercury levels. In conclusion, these results suggest that current exposure was associated with cognitive test responses except for the ECF Copy test and WISC Symbol test.

Monday, 25 July, 2011