Local Fish Consumption Research Articles

Levels of organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers in fish species from Kahramanmaras, Turkey

The levels of organohalogenated contaminants, such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in four fish species ( Acanthobrama marmid (kalashpa), Cyprinus carpio (carp), Chondrostoma regium (nose-carp), and Silurus glanis (wels)) from the Sir Dam Lake, Kahramanmaras, Turkey. These species were selected for their characteristic feeding behaviour and their importance to local human fish consumption. DDTs were the predominant organohalogenated contaminants in all species, with the p, p′-DDE contributing to more than 90% to the total DDTs. Other OCPs, such as hexachlorocyclohexane (HCH) isomers, chlordanes and hexachlorobenzene (HCB) were found at much lower levels in all five species. The levels of PCBs and PBDEs (on wet weight basis) were lower than in similar species from European or American freshwater systems. PBDE data were measured for the first time in fish species from Turkish environment. Lipid-based concentrations of OCPs, PCBs and PBDEs were higher in wels than in the other species and this was related to its piscivorous feeding mode and to its higher lipid content. Contrarily, concentrations of pollutants in nose-carp were the lowest, in agreement with its more herbivorous diet. A preferential accumulation in muscle compared to liver was observed for all OCPs, PCBs, and PBDEs in wels and carp, while in nose-carp, a preferential accumulation in liver was observed only for PBDEs, p, p′-DDT and PCBs. Racemic amounts for α-HCH were measured in all investigated muscle and liver samples, except for carp muscle.

Low-Level Methylmercury Exposure as a Risk Factor for Neurologic Abnormalities in Adults

Methylmercury is a neurotoxicant that bio-accumulates in the aquatic food chain and is present in all fish. Little is known about the effects of long-term low-dose exposure to methylmercury in adults. The aim of this study was to determine whether a dose–response relationship exists between long-term methylmercury exposure and neurological abnormalities in aboriginal Quebec Cree adults for whom fish is a dietary staple. We re-analysed data from a 1977 cross-sectional study conducted by Kofman and collaborators on a group of Quebec Cree individuals claiming ill health from local fish consumption. In the original 1977 study, 306 adult participants aged 18–82 years were assessed for methylmercury exposure. Tremor and other neurologic outcomes were assessed with a clinical examination. The investigators did not find clinical evidence of methylmercury intoxication based on an analysis of covariance. We used ordinal regression to obtain odds ratios for the relationship between total hair mercury levels and neurologic abnormalities. Hair mercury concentrations ranged from 0.5 to 46 ppm (parts per million). A 6 ppm increase in hair mercury was associated with increasing levels of tremor (OR, 2.22; 95%CI, 1.15–4.26) in adults under 40 years of age. There was no association with nine other outcomes considered, nor with tremor among older persons. Odds ratios were not influenced by gender, smoking, alcohol use, or co-morbidity. Conclusion: Dose-dependent effects of methylmercury on tremor may occur below the commonly accepted 50 ppm threshold, particularly in young adults. These effects may be detectable by clinical examination. However, the results should be interpreted with caution given that alcohol use was probably under-reported and that multiple outcomes were studied.

Fish consumption and other environmental exposures and their associations with serum PCB concentrations among Mohawk women at Akwesasne

A study was conducted with the objective of assessing how dietary, occupational, and residential exposures to polychlorinated biphenyls (PCBs) contribute to body burden among pregnant Mohawk women residing near three hazardous waste sites. From 1992 to 1995, 111 pregnant women were interviewed about fish consumption and other environmental risk factors and donated a 20-mL venous blood sample for serum PCB analysis. To supplement previous fish sampling, samples of residential soil, ambient air, wild duck, and local meats and vegetables were also collected and analyzed for PCBs. The results indicated a significant decline in local fish consumption from an annual mean of 31.3 meals more than 1 year prior to pregnancy to an annualized mean of 11.7 meals during pregnancy. This change was reportedly a result of the advisories issued against consumption of local fish by pregnant and nursing women of childbearing age. The geometric mean concentration of total PCBs in the serum was 1.2 ppb, a level that is similar to that in other studies of women with no unusual exposures to PCBs. However, multiple regression analysis revealed that serum levels of total PCBs and three individual congeners were associated with local fish consumption. The PCB levels in soil, air, and local foodstuffs other than fish generally were not elevated, except for those obtained in close proximity to one of the hazardous waste sites, and no association was found between serum PCB levels and exposure through these media or through occupation.

The Passaic River Creel/Angler Survey: Expert Panel Review, Findings, and Recommendations

A Creel/Angler Survey (CAS) was conducted to provide site-specific information on recreational fishing in the lower six miles of the Passaic River (Study Area). Information collected during the CAS will be used to develop site-specific exposure factors, including fish consumption rates, for use in the human health risk assessment required by an Administrative Order on Consent as part of the Remedial Investigation/Feasibility Study for the Study Area. An expert panel was convened to provide an independent opinion regarding the need for, design of, and implementation of the CAS. The expert panel was charged with evaluating whether the conduct of a CAS is necessary to support an accurate risk assessment for the Study Area and whether the proposed CAS is sufficient to characterize local fish consumption behavior for risk assessment purposes. The expert panel agreed that a CAS is necessary and concluded that the proposed CAS, with specific modifications to the study design and data analysis, would provide the information necessary to estimate site-specific fish consumption rates. Revision of the CAS to accommodate the expert panel recommendations enhanced the quality of the data collected and ensured that the data will support the assessment of human health risks from consumption of fish from the Study Area.

The association between local fish consumption and DDE, mirex, and HCB concentrations in the breast milk of Mohawk women at Akwesasne.

A study was conducted to assess the extent to which the consumption of local fish contaminated with p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE), mirex, and hexachlorobenzene (HCB) has impacted the concentrations of these compounds in the milk of nursing Mohawk women residing along the St. Lawrence River. From 1986 to 1992, 97 Mohawk women were interviewed, and each donated a one-time sample of at least 50 ml of breast milk. The comparison population consisted of 154 Caucasians from other rural areas in New York State. After adjustment for potential confounders, Mohawk mothers who gave birth from 1986 to 1990 had significantly higher geometric mean p,p'-DDE milk concentrations than did the control group, but no significant differences were observed from 1991 to 1992. In contrast, mirex was significantly elevated among the Mohawks throughout the study period, while HCB showed no difference at any point. Mohawk women with the greatest estimated cumulative lifetime exposure to p,p'-DDE from local fish consumption had a significantly higher geometric mean milk level of that compound relative to control women, but no differences in mirex or HCB concentrations in breast milk by local fish consumption were found. The reduction in breast milk p,p'-DDE concentrations among the Mohawk women from 1986 to 1990 parallels a corresponding decrease in local fish consumption, and may be the result of the advisories that have been issued over the past decade recommending against the consumption of local fish by pregnant and nursing Mohawk women. Elevations in the concentrations of mirex in the breast milk of the Mohawks are consistent with the fact that it is a common contaminant in the region and throughout the Lake Ontario-St. Lawrence River Basin.

Assessment of Levels, Distribution, and Risks of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in the Vicinity of a Vinyl Chloride Monomer Production Plant

Levels of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were analyzed from environmental and human samples to assess contaminant distribution and risks associated with vinyl chloride monomer (VCM) production. Extremely high concentration of PCDD/Fs, 26 μg/g dry weight, was detected in the waste sludge. As a result of improper wastewater treatment practices in the 1970s, PCDD/Fs (11.4 kg, 32.0 g of I-TEQ) leached into the Gulf of Finland in the Baltic Sea. Despite high concentrations near the plant, the polluted area was restricted (about 26 km2), and VCM production could not be a significant contributor to the PCDD/F load of the sea. Frequent consumption of local fish was considered to be the most probable source of human exposure. However, serum samples taken from local residents and former workers did not indicate exposure to elevated levels of total PCDD/Fs. Octachlorinated furan was the main congener (73% of PCDD/F sum) in the waste sludge, and it also dominated in marine sediments. Contaminated sediments also had a characteristic PCB composition, containing exceptionally high proportions of IUPAC 206 and 209 congeners.

Human Exposure to Mercury and the Accumulation of Methylmercury that is Associated with Gold Mining in the Amazon Basin, Brazil.

In order to evaluate the extent of human exposure to mercury in the Amazon, in particular, in the Tapajos River basin, which is a site of extensive alluvial gold mining, we analyzed samples of human hair, blood and urine, as well as fish, collected from different areas for total levels of mercury and methylmercury. In fishing villages, the inhabitants were found to have accumulated mercury, mostly in the form of methylmercury, at abnormally high levels as the apparent result of consumption of local fish, with very little confounding exposure to inorganic mercury, including mercury vapor in the air. The people living near the main gold-mining areas had accumulated higher levels of methlymercury than people living far downstream from the gold-mining sites. Quite high levels of methylmercury were found in samples of hair from inhabitants of the fishing villages.

Plasma phospholipid fatty acids in the central Canadian arctic: biocultural explanations for ethnic differences.

As part of the Keewatin Health Assessment Study, a comprehensive health interview and examination survey of Inuit and non-Inuit in the central Canadian Arctic during 1990-91, plasma samples were analyzed for phospholipid fatty acid composition. Compared to non-Inuit, the Inuit have reduced levels of dihomo-gamma-linoleic (DGLA) and arachidonic acid (ratios of 0.41 and 0.46) and the sum of all n-6 fatty acids (ratio of 0.65), but increased level of eicosapentaenoic (EPA) acid (ratio of 1.37). These trends are consistent with those reported from other circumpolar Inuit populations, especially the reduced arachidonic acid and increased EPA, although the Inuit excess in EPA is much less pronounced due to the greater importance of caribou rather than sea mammals in most of the Keewatin communities. The high linoleic/arachidonic acid ratio suggests increased inhibition of the metabolic pathway regulated by the enzyme delta-5 desaturase, which can be explained by the presence of high levels of highly unsaturated fatty acids of dietary origin, and/or a genetic deficiency. In multiple linear regression models with the independent variable list consisting of Inuit status, age, sex, education, physical activity, spending time on the land and consumption of wild meat and local fish, Inuit status is independently associated with lower levels of the n-6 acids but not the n-3 acids. This indicates that factors other than diet and lifestyle, perhaps genetic ones, may account for the observed "ethnic" differences. However, for those fatty acids in which Inuit differ from non-Inuit, there is no dose-response relationship in terms of self-reported degree ofnon-Inuit admixture. Dietary fatty acids play an important role in the risk of cardiovascular diseases and diabetes, diseases of increasing importance in the health transition experienced by the Inuit. Association studies of plasma fatty acids and DNA markers of candidate genes for atherosclerosis and insulin resistance may provide a clearer picture of the genetic basis for the observed differences in plasma fatty acid composition between Inuit and non-Inuit.

Local Fish Consumption and Serum PCB Concentrations among Mohawk Men at Akwesasne

A study was conducted to assess local fish consumption patterns and their relationship to concentrations of total polychlorinated biphenyls (PCBs) in the serum of Mohawk men residing near three hazardous waste sites. From 1992 to 1995, 139 men were interviewed and donated a 20-ml venous blood sample. The results indicated that the men ate a mean of 21.2 local fish meals during the past year, compared with annual means of 27.7 meals 1–2 years before and 88.6 meals more than 2 years before (P<0.001 for test of trend). This change is probably a consequence of advisories issued against the consumption of local fish, since 97% of the men were aware of the advisories and two-thirds had changed their behavior as a result. Multiple regression analysis revealed that serum PCB levels increased with age (β=0.036,P<0.001) and local fish consumption (β=0.088,P=0.006). The data suggest that local fish consumption has contributed to body burdens in this population and that the advisories have been effective in modifying local fish consumption habits.

Case-control study of leukaemia among young people near La Hague nuclear reprocessing plant: the environmental hypothesis revisited

Objective: To investigate the association between childhood leukaemia and established risk factors or other factors related to La Hague nuclear waste reprocessing plant.Design: Case-control study.Setting: Area within a 35 km...

Food self-sufficiency in Micronesia: Effects of a nutrition assistance programme on food consumption

Food assistance programmes in Micronesia have been blamed for creating disincentives to agriculture and nutritionally adverse dietary habits. In 1982 a USDA commodity programme in the Northern Mariana Islands was replaced by the Nutrition Assistance Program (NAP), which required that at least 25% of food coupons be used for the purchase of local foods. Consumption of local fish and bread increased, but consumption of local fruits and vegetables declined among NAP participants. Although targeted coupons did not reverse the trend towards imported foods, the bakery and fishery endeavours indicate that improved marketing can be coupled with food stamps to increase local food production and consumption.

The case for the African catfish, Clarias gariepinus Burchell, 1822, Clariidae: a comparison of the relative merits of Tilapiine fishes, especially Oreochromis niloticus (L.) and C. gariepinus Burchell, for African aquaculture

Abstract. The relative merits of tilapiine fishes, especially Oreochromis niloticus (L.) and Clarias gariepinus Burchell, are compared with respect to their suitability for aquaculture in Africa. Reproductive, nutritional and production data are drawn where possible from work carried out under African conditions. In view of the fact that African aquaculture is insignificant in terms of worldwide production and in terms of local fish consumption it is suggested that a broader view of species choice might be adopted in relation to aquaculture projects. The African catfish, by virtue of its suitable reproductive strategy, its nutritional efficiency and its ability to breath atmospheric oxygen, clearly represents an excellent candidate for aquaculture in Africa.

Neurobehavioral assessment of Mohawk Indians for subclinical indications of methyl mercury neurotoxicity.

A total of 200 male and 200 adult female Mohawk Indians were examined by means of performance tests as part of a total health evaluation of participants in a medical field survey on the St. Regis Reserve. Age-corrected performance test scores were studied in relation to blood, urinary, and hair methyl mercury (MeHg) levels, and local fish consumption. Males were found to eat more fish than females and had relatively higher MeHg levels than females. Blood and hair MeHg levels were significantly correlated with local fish consumption for both sexes. Biological indicators of MeHg absorption suggested low exposure levels but did not correlate significantly with performance test scores. These findings indicate that the time of examination, St. Regis residents were exposed to almost "background" levels of MeHg and did not exhibit either subclinical or clinical manifestations of MeHg neurotoxicity.

Association of Blood Pressure and Polychlorinated Biphenyl Levels

The geometric mean serum level of polychlorinated biphenyls (PCBs) of 458 persons in a communitywide study was 17.2 microgram/L, with 80% to 90% having levels within the range found in other community groups. As a dependent variable, PCB levels were found to be positively related to age, even when controlled for all other variables associated with PCB level: sex, local fish consumption, obesity, serum cholesterol level, and alcohol consumption. No major point source of PCB contamination was found, and fish taken in the drainage of a major population center had mean PCB levels below the current enforceable Food and Drug Administration tolerance of 5 mg/kg. As an independent variable, serum PCB levels were positively associated with gamma-glutamyl transpeptidase level, serum cholesterol level, and measured blood pressure. The PCB-blood pressure association, which was independent of age, sex, body mass index, and social class, must be confirmed in other exposed populations.