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Water: News

Newsletter—October 2011

  Black Canyon of the Yellowstone River near Gardiner, Montana

Black Canyon of the Yellowstone River near Gardiner, Montana by Mike Cline (Own work) [GFDL (www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0/) or CC-BY-SA-2.5-2.0-1.0 (www.creativecommons.org/licenses/by-sa/2.5-2.0-1.0)], via Wikimedia Commons

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Recent Advisory News

New mercury advisories added in Utah

The Utah Health Department recently released new and revised fish consumption advisories in conjunction with the state’s Wildlife Resources and Water Quality divisions. New fish advisories were issued for black bullhead at Recapture Reservoir and for brown trout from the Duchesne River near Tabiona and from the Bough Reservoir. In addition, fish species were added to existing advisories for Newcastle, Red Fleet and Steinaker reservoirs. During the past decade, Utah’s state agencies have tested more than 2,500 fish from 322 waterways. Average mercury concentrations have been found to exceed the U.S. Environmental Protection Agency (EPA) limit at 19 locations, where advisories are now in effect.

Link to original article: http://www.sltrib.com/sltrib/politics/52440174-90/advisories-consumption-county-eat.html.csp

Salt Lake Tribune (UT), 8/23/2011.

Fish tested for radioactivity near Vermont nuclear plant

The Vermont Department of Health recently reported that it detected Strontium-90, a radioactive material, in a fish from the Connecticut River near Entergy's Vermont Yankee nuclear power plant. "One finding of (Strontium-90) just above the lower limit of detection in one fish sample is notable because it is the first time Strontium-90 has been detected in the edible portion of any of our fish samples," the Vermont Department of Health said on its website. Health officials did not speculate as to how the Strontium-90, which is both naturally occurring in the environment and a byproduct of nuclear power production and nuclear weapons testing, got into the fish. Additional analyses will be performed to try to determine the source and extent of the contamination.

Link to original press release: http://uk.reuters.com/article/2011/08/02/us-utilities-entergy-vermontyankee-stron-idUKTRE77160420110802

Source: Reuters (International), 8/2/2011.

South Dakota adds mercury advisories, considers EPA threshold value

South Dakota officials have recently updated the state’s list of fish advisories. There are now 12 lakes with consumption advisories for mercury. State health officials have said that higher water levels after years of drought might have been a factor in the recent increase of advisories for state waters. South Dakota is currently working to determine whether to change the advisory threshold level for mercury in fish tissue from the Food and Drug Administration standard of 1 ppm to the EPA level of 0.3 ppm. State fisheries crews expanded their sampling this year to get a broader base of data on state fishing waters and fish species prior to making a determination on the mercury threshold value.

Link to original article: http://rapidcityjournal.com/news/state-expands-list-of-waters-under-mercury-advisory/article_ec75bc80-d45e-11e0-821e-001cc4c002e0.html

Source: Rapid City Journal (SD), 9/1/2011.

Yellowstone River fish declared safe to eat

Laboratory results released by Montana Fish, Wildlife & Parks revealed that no oil was detected in fillets cut from about 60 fish taken from the Yellowstone river in mid-July, although trace amounts of oil were detected in the livers and gonads of some fish. State officials said the contamination was not a health risk to people who catch and eat the fish, and they rescinded the fish consumption warning that was issued in early July after an Exxon Mobil pipeline broke and leaked an estimated 42,000 gallons of oil into the Yellowstone River.

Link to original article: http://www.greatfallstribune.com/article/G1/20110825/NEWS01/110825013/State-Yellowstone-fish-safe-some-oil-found

Source: Great Falls Tribune (MT), 8/25/2011.

Military suicides linked to low Omega-3 levels

A recent study found that U.S. servicemen who had low blood levels of docosahexaenoic acid (DHA), an Omega-3 fatty acid found in fish oil, were 62% more likely to have been suicide victims than those with the highest levels of DHA. The researchers reviewed the medical records of 800 U.S. servicemen and women who took their own lives between 2002 and 2008, and compared them with the records of 800 service personnel, matched for age, gender and rank, who had no history of suicide attempts. The study, published in the Journal of Clinical Psychiatry, suggests that low DHA levels were an even stronger predictor of suicide than a previously better known risk factor: whether the service member reported having had direct exposure to allied troops that had been killed or wounded.

Link to original article: http://articles.latimes.com/2011/aug/24/news/la-heb-suicide-military-omega3-20110824

Source: The Los Angeles Times (CA), 8/24/2011.

Recent Publications

Please note: The following abstracts are reprinted verbatim unless otherwise noted.

Effects of biologically-active chemical mixtures on fish in a wastewater-impacted urban stream

Stream flow in urban aquatic ecosystems often is maintained by water-reclamation plant (WRP) effluents that contain mixtures of natural and anthropogenic chemicals that persist through the treatment processes. In effluent-impacted streams, aquatic organisms such as fish are continuously exposed to biologically-active chemicals throughout their life cycles. The North Shore Channel of the Chicago River (Chicago, Illinois) is part of an urban ecosystem in which >80% of the annual flow consists of effluent from the North Side WRP. In this study, multiple samplings of the effluent and stream water were conducted and fish (largemouth bass and carp) were collected on 2 occasions from the North Shore Channel. Fish also were collected once from the Outer Chicago Harbor in Lake Michigan, a reference site not impacted by WRP discharges. Over 100 organic chemicals with differing behaviors and biological effects were measured, and 23 compounds were detected in all of the water samples analyzed. The most frequently detected and highest concentration (>100µg/L) compounds were ethylenediaminetetraacetic acid and 4-nonylphenolmono-to-tetraethoxycarboxylic acids. Other biologically-active chemicals including bisphenol A, 4-nonylphenol, 4-nonylphenolmono-to-tetraethoxylates, 4-tert-octylphenol, and 4-tert-octylphenolmono-to-tetraethoxylates were detected at lower concentrations (<5mug/L). The biogenic steroidal hormones 17beta-estradiol, estrone, testosterone, 4-androstene-3,17-dione, and cis-androsterone were detected at even lower concentrations (<0.005µg/L). There were slight differences in concentrations between the North Side WRP effluent and the North Shore Channel, indicating minimal in-stream attenuation. Fish populations are continuously exposed to mixtures of biologically-active chemicals because of the relative persistency of the chemicals with respect to stream hydraulic residence time, and the lack of a fresh water source for dilution. The majority of male fish exhibited vitellogenin induction, a physiological response consistent with exposure to estrogenic compounds. Tissue-level signs of reproductive disruption, such as ovatestis, were not observed.

Source: Barber, L. B., G. K. Brown, et al. (2011). "Effects of biologically-active chemical mixtures on fish in a wastewater-impacted urban stream." Sci Total Environ 2011 Aug 15. [Epub ahead of print].

Omega-3 fatty acids and incident type 2 diabetes: the Singapore Chinese Health Study

BACKGROUND: The role of omega-3 (n-3) fatty acids (FAs) in the development of type 2 diabetes is uncertain, especially with regard to any differential influence of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). OBJECTIVE: The objective was to examine the association between total omega-3 FAs, marine omega-3 (EPA, DHA), nonmarine omega-3 (ALA), and omega-6 (n-6) FAs and omega-6:omega-3 ratio and risk of type 2 diabetes in a Chinese population in Singapore. DESIGN: The analysis included 43,176 Chinese men and women free of chronic disease, aged 45-74 y, in the Singapore Chinese Health Study. Baseline data collection occurred between 1993 and 1998, with follow-up interviews between 1999 and 2004. Cox regression models were used to examine the associations between FA intakes at baseline and risk of developing diabetes. RESULTS: Increased intakes of total omega-3 FAs were inversely associated with diabetes incidence [hazard ratio (HR) for the fifth compared with the first quintile: 0.78; 95% CI: 0.65, 0.94; P for trend = 0.02]. Omega-3 FAs from marine sources were not associated with diabetes risk, whereas nonmarine omega-3 FA intake was strongly associated (HR for the fifth compared with the first quintile: 0.79; 95% CI: 0.67, 0.93; P for trend = 0.004). Omega-6 and omega-6:omega-3 ratio were not associated with incidence of type 2 diabetes. CONCLUSION: Consumption of nonmarine sources (ALA) of omega-3 FAs is associated with a decreased risk of type 2 diabetes in Chinese Singaporeans.

Source: Brostow, D. P., A. O. Odegaard, et al. (2011). "Omega-3 fatty acids and incident type 2 diabetes: the Singapore Chinese Health Study." Am J Clin Nutr 94(2): 520-526.

Mercury policy in the Great Lakes states: past successes and future opportunities

While mercury (Hg) releases to air and water within the Great Lakes states have declined significantly, concentrations of mercury in fish remain a cause for concern regarding human and ecosystem health in the Great Lakes Basin. This paper assesses the priority that Hg source reduction ought to have in relation to some other environmental concerns, and explores the relative costs of various Hg reduction policies. Long-range transport of atmospheric mercury creates a collective action problem for states, since most of the mercury emitted within any given state deposits outside that state's borders, and since most of the mercury deposited within a state originated outside that state. This paper discusses some of the mechanisms that policy makers in the Great Lakes states employed to get beyond the collective action problem, including: providing an example for others to follow; using cross-jurisdiction cooperation to leverage the benefits of leadership on Hg reduction and control; and, promoting voluntary actions. Recommendations for future opportunities include: focusing reduction efforts on sources with the highest total mass of emissions rather than solely focusing on reduction of local deposition and utilizing all tools available in the clean air and clean water acts.

Source: Cain, A., J. T. Morgan, et al. (2011). "Mercury policy in the Great Lakes states: past successes and future opportunities." Ecotoxicology 2011 Aug 23. [Epub ahead of print].

Do Temporal and Geographical Patterns of HBCD and PBDE Flame Retardants in U.S. Fish Reflect Evolving Industrial Usage?

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) are common flame retardants in polymers and textiles. Recognition of the persistent, bioaccumulative, and toxic properties of PBDEs has prompted reductions in their use. In contrast, HBCD has received less scrutiny. The U.S has historically been a dominant BFR consumer. However, the few publications on HBCD in wildlife here suggest modest levels compared to Asian and European studies. In contrast, the HBCD concentrations we detected in U.S. fish are among the highest reported in the world. The temporal trends observed suggest that HBCD use may have risen, and that of Penta-BDE declined, following the 2004 termination of its U.S. manufacture. For example, Hyco River carp collected in 1999-2002 exhibited a mean summation operatorHBCD (sum of alpha-, beta- and gamma-HBCD) concentration of only 13 ng/g (lipid weight basis), but was 4640 ng/g in fish collected in 2006-2007. In contrast, the mean summation operatorPBDE level in these same fish decreased from 40,700 ng/g in 1999-2002 to 9140 ng/g in 2006-2007. Concentrations of HBCD and PBDEs in several Hyco River fish species exceeded those from rivers less influenced by manufacturing outfalls. Results support the contention that textile-related production, relative to its BFR market share, may release disproportionately large amounts of HBCD to the environment.

Source: Drenner, R. W., M. M. Chumchal, et al. (2011). "Landscape-level patterns of mercury contamination of fish in North Texas, USA." Environ Toxicol Chem 2011 Jun 3. doi: 10.1002/etc.589. [Epub ahead of print].

Dietary intakes of arachidonic acid and alpha-linolenic acid are associated with reduced risk of hip fracture in older adults

PUFA are hypothesized to influence bone health, but longitudinal studies on hip fracture risk are lacking. We examined associations between intakes of PUFA and fish, and hip fracture risk among older adults (n = 904) in the Framingham Osteoporosis Study. Participants (mean age ~75 y at baseline) were followed for incident hip fracture from the time they completed the baseline exam (1988-1989) until December 31, 2005. HR and 95% CI were estimated for energy-adjusted dietary fatty acid exposure variables [(n-3) fatty acids: alpha-linolenic acid (ALA), EPA, DHA, EPA+DHA; (n-6) fatty acids: linoleic acid, arachidonic acid (AA); and the (n-6):(n-3) ratio] and fish intake categories, adjusting for potential confounders and covariates. Protective associations were observed between intakes of ALA (P-trend = 0.02) and hip fracture risk in a combined sample of women and men and between intakes of AA (P-trend = 0.05) and hip fracture risk in men only. Participants in the highest quartile of ALA intake had a 54% lower risk of hip fracture than those in the lowest quartile (Q4 vs. Q1: HR = 0.46; 95% CI = 0.26-0.83). Men in the highest quartile of AA intake had an 80% lower risk of hip fracture than those in the lowest quartile (Q4 vs. Q1: HR = 0.20; 95% CI = 0.04-0.96). No significant associations were observed among intakes of EPA, DHA, EPA+DHA, or fish. These findings suggest dietary ALA may reduce hip fracture risk in women and men and dietary AA may reduce hip fracture risk in men.

Source: Chen, D., M. J. La Guardia, et al. (2011). "Do Temporal and Geographical Patterns of HBCD and PBDE Flame Retardants in U.S. Fish Reflect Evolving Industrial Usage?" Environ Sci Technol 2011 Sep 8. [Epub ahead of print].

Fish consumption and prenatal methylmercury exposure: Cognitive and behavioral outcomes in the main cohort at 17 years from the Seychelles child development study

INTRODUCTION: People worldwide depend upon daily fish consumption as a major source of protein and other nutrients. Fish are high in nutrients essential for normal brain development, but they also contain methylmercury (MeHg), a neurotoxicant. Our studies in a population consuming fish daily have indicated no consistent pattern of adverse associations between prenatal MeHg and children's development. For some endpoints we found performance improved with increasing prenatal exposure to MeHg. Follow up studies indicate this association is related to the beneficial nutrients present in fish. OBJECTIVES: To determine if the absence of adverse outcomes and the presence of beneficial associations between prenatal MeHg and developmental outcomes previously reported persists into adolescence. METHODS: This study was conducted on the Main Cohort of the Seychelles Child Development Study (SCDS). We examined the association between prenatal MeHg exposure and subjects' performance at 17 years of age on 27 endpoints. The test battery included the Wisconsin Card Sorting Test (WCST), the California Verbal Learning Test (CVLT), the Woodcock-Johnson (W-J-II) Achievement Test, subtests of the Cambridge Neuropsychological Test Automated Battery (CANTAB), and measures of problematic behaviors. Analyses for all endpoints were adjusted for postnatal MeHg, sex, socioeconomic status, maternal IQ, and child's age at testing and the child's IQ was added for problematic behavioral endpoints. RESULTS: Mean prenatal MeHg exposure was 6.9ppm. There was no association between prenatal MeHg and 21 endpoints. Increasing prenatal MeHg was associated with better scores on four endpoints (higher W-J-II math calculation scores, reduced numbers of trials on the Intra-Extradimensional Shift Set of the CANTAB), fewer reports of substance use and incidents of and referrals for problematic behaviors in school. Increasing prenatal MeHg was adversely associated with one level of referrals to a school counselor. CONCLUSIONS: At age 17 years there was no consistent pattern of adverse associations present between prenatal MeHg exposure and detailed domain specific neurocognitive and behavioral testing. There continues to be evidence of improved performance on some endpoints as prenatal MeHg exposure increases in the range studied, a finding that appears to reflect the role of beneficial nutrients present in fish as demonstrated previously in younger subjects. These findings suggest that ocean fish consumption during pregnancy is important for the health and development of children and that the benefits are long lasting.

Source: Davidson, P. W., D. A. Cory-Slechta, et al. (2011). "Fish consumption and prenatal methylmercury exposure: Cognitive and behavioral outcomes in the main cohort at 17 years from the Seychelles child development study." Neurotoxicology 2011 Aug 25. [Epub ahead of print].

Spatial gradients of methylmercury for breeding common loons in the Laurentian Great Lakes region

Much of the Laurentian Great Lakes region is a mercury-sensitive landscape, in which atmospheric deposition and waterborne sources of mercury (Hg) have led to high concentrations of bioavailable methylmercury (MeHg) in predatory fish and piscivorous wildlife. Efforts since the early 1990s have established the common loon (Gavia immer) as the primary avian indicator for evaluating the exposure and effects of MeHg in North America. A regional Hg dataset was compiled from multiple loon tissue types and yellow perch (Perca flavescens), a preferred prey fish species for loons. Hg exposure in loons and perch was modeled to develop male and female loon units (MLU and FLU, respectively), standardized metrics that represent the estimated blood Hg exposure of a male or female loon for a given loon territory or water body. Using this common endpoint approach to assess loon Hg exposure, the authors demonstrate spatial trends in biotic Hg concentrations, examine MeHg availability in aquatic ecosystems of the Great Lakes region in relation to landscape-level characteristics, and identify areas with potentially significant adverse reproductive impacts to loons and other avian piscivores. Based on 8,101 MLUs, seven biological Hg hotspots were identified in the Great Lakes region. Policy-relevant applications are presented.

Source: Evers, D. C., K. A. Williams, et al. (2011). "Spatial gradients of methylmercury for breeding common loons in the Laurentian Great Lakes region." Ecotoxicology 2011 Aug 20. [Epub ahead of print].

A review of seafood safety after the Deepwater Horizon blowout

BACKGROUND: The Deepwater Horizon (DH) blowout resulted in fisheries closings across the Gulf of Mexico. Federal agencies, in collaboration with impacted Gulf states, developed a protocol to determine when it is safe to reopen fisheries based on sensory and chemical analyses of seafood. All federal waters have been reopened, yet concerns have been raised regarding the robustness of the protocol to identify all potential harmful exposures and protect the most sensitive populations. OBJECTIVES: We aimed to assess this protocol based on comparisons with previous oil spills, published testing results, and current knowledge regarding chemicals released during the DH oil spill. METHODS: We performed a comprehensive review of relevant scientific journal articles and government documents concerning seafood contamination and oil spills and consulted with academic and government experts. RESULTS: Protocols to evaluate seafood safety before reopening fisheries have relied on risk assessment of health impacts from polycyclic aromatic hydrocarbon (PAH) exposures, but metal contamination may also be a concern. Assumptions used to determine levels of concern (LOCs) after oil spills have not been consistent across risk assessments performed after oil spills. Chemical testing results after the DH oil spill suggest PAH levels are at or below levels reported after previous oil spills, and well below LOCs, even when more conservative parameters are used to estimate risk. CONCLUSIONS: We recommend use of a range of plausible risk parameters to set bounds around LOCs, comparisons of post-spill measurements with baseline levels, and the development and implementation of long-term monitoring strategies for metals as well as PAHs and dispersant components. In addition, the methods, results, and uncertainties associated with estimating seafood safety after oil spills should be communicated in a transparent and timely manner, and stakeholders should be actively involved in developing a long-term monitoring strategy.

Source: Gohlke, J. M., D. Doke, et al. (2011). "A review of seafood safety after the deepwater horizon blowout." Environ Health Perspect 119(8): 1062-1069.

Diet before pregnancy and the risk of hyperemesis gravidarum

Hyperemesis gravidarum (hyperemesis), characterised by severe nausea and vomiting in early pregnancy, has an unknown aetiology. The aim of the present study was to investigate food and nutrient intake before pregnancy and the risk of developing hyperemesis in women participating in the Norwegian Mother and Child Cohort Study. From 1999 to 2002, a total of 7710 pregnant women answered a FFQ about their diet during the 12 months before becoming pregnant and a questionnaire about illnesses during pregnancy, including hyperemesis. Only women who were hospitalised for hyperemesis were included as cases. Nutrient intakes during the year before pregnancy did not differ between the ninety-nine women who developed hyperemesis and the 7611 who did not. However, the intake of seafood, allium vegetables and water was significantly lower among women who developed hyperemesis than among women in the non-hyperemesis group. Relative risks of hyperemesis were approximated as OR, and confounder control was performed with multiple logistic regression. Women in the upper tertile of seafood consumption had a lower risk of developing hyperemesis than those in the lower tertile (OR 0.56, 95 % CI 0.32, 0.98), and women in the second tertile of water intake had a lower risk of developing hyperemesis than those in the first tertile (OR 0.43, 95 % CI 0.25, 0.73). The findings suggest that a moderate intake of water and adherence to a healthy diet that includes vegetables and fish are associated with a lower risk of developing hyperemesis.

Source: Haugen, M., A. Vikanes, et al. (2011). "Diet before pregnancy and the risk of hyperemesis gravidarum." Br J Nutr 106(4): 596-602.

Role of mercury toxicity in hypertension, cardiovascular disease, and stroke

Mercury has a high affinity for sulfhydryl groups, inactivating numerous enzymatic reactions, amino acids, and sulfur-containing antioxidants (N-acetyl-L-cysteine, alpha-lipoic acid, L-glutathione), with subsequent decreased oxidant defense and increased oxidative stress. Mercury binds to metallothionein and substitute for zinc, copper, and other trace metals, reducing the effectiveness of metalloenzymes. Mercury induces mitochondrial dysfunction with reduction in adenosine triphosphate, depletion of glutathione, and increased lipid peroxidation. Increased oxidative stress and reduced oxidative defense are common. Selenium and fish containing omega-3 fatty acids antagonize mercury toxicity. The overall vascular effects of mercury include increased oxidative stress and inflammation, reduced oxidative defense, thrombosis, vascular smooth muscle dysfunction, endothelial dysfunction, dyslipidemia, and immune and mitochondrial dysfunction. The clinical consequences of mercury toxicity include hypertension, coronary heart disease, myocardial infarction, cardiac arrhythmias, reduced heart rate variability, increased carotid intima-media thickness and carotid artery obstruction, cerebrovascular accident, generalized atherosclerosis, and renal dysfunction, insufficiency, and proteinuria. Pathological, biochemical, and functional medicine correlations are significant and logical. Mercury diminishes the protective effect of fish and omega-3 fatty acids. Mercury inactivates catecholaminei-0-methyl transferase, which increases serum and urinary epinephrine, norepinephrine, and dopamine. This effect will increase blood pressure and may be a clinical clue to mercury-induced heavy metal toxicity. Mercury toxicity should be evaluated in any patient with hypertension, coronary heart disease, cerebral vascular disease, cerebrovascular accident, or other vascular disease. Specific testing for acute and chronic toxicity and total body burden using hair, toenail, urine, and serum should be performed.

Source: Houston, M. C. (2011). "Role of mercury toxicity in hypertension, cardiovascular disease, and stroke." J Clin Hypertens (Greenwich) 13(8): 621-627.

Fishing, fish consumption and advisory awareness among Louisiana's recreational fishers

This paper presents results from the first known population-based survey of recreational fishers in Louisiana (n=1774). The ultimate goal of this study was to obtain data in support of the development of regional advisories for a high exposure population with unique seafood consumption patterns. Between July and August of 2008, a survey was mailed to a random sample of licensed recreational fishers to characterize local fishing habits, sportfish consumption, and advisory awareness. Eighty-eight percent of respondents reported eating sportfish. Respondents ate an estimated mean of four fish meals per month, of which, approximately half were sportfish. Over half of all sportfish meals (54%) were caught in the Gulf of Mexico or bordering brackish areas. Sportfish consumption varied by license and gender; and was highest among Sportsman's Paradise license holders (2.8+/-0.2 meals per month), and males (2.2+/-0.1 meals per month). The most frequently consumed sportfish species were red drum, speckled trout, catfish, bass, crappie and bream. Advisory awareness rates varied by gender, ethnicity, geographic area, license type, age and education; and were lowest among women (53%), African-Americans (43%), fishers from the southeast of Louisiana (50%), holders of Senior Hunting and Fishing licenses (51%), individuals between 15 and 19 years of age (41%), and individuals with less than a high school education (43%). Results were used to identify ways to optimize monitoring, advisory development and outreach activities.

Source: Katner, A., E. Ogunyinka, et al. (2011). "Fishing, fish consumption and advisory awareness among Louisiana's recreational fishers." Environ Res 2011 Aug 16. [Epub ahead of print].

Flesh residue concentrations of organochlorine pesticides in farmed and wild salmon from British Columbia, Canada

The present study reports measured levels of organochlorine pesticides (OCPs) in commercial salmon feed (n = 8) and farmed Atlantic, coho and chinook salmon (n = 110), as well as wild coho, chinook, chum, sockeye, and pink salmon (n = 91). Flesh residue concentrations (ng/g wet weight) of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), chlordanes, chlorobenzenes (CBz) and cyclodiene pesticides (e.g., dieldrin, mirex) were two to 11 times higher (p < 0.05) in farmed salmon compared to wild salmon. Concentrations were positively correlated with flesh lipid levels. Farmed Atlantic salmon (12 to 15% lipid) typically exhibited the greatest OCP burdens compared to other salmon species. However, when expressed on a lipid weight basis, concentrations of OCPs (ng/g lipid weight) in wild salmon, in many cases, exceeded those levels in farmed salmon. Observed interspecies and site-specific variations of OCP concentrations in farmed and wild salmon may be attributed to divergent life history, prey/feed characteristics and composition, bioenergetics and/or ambient environmental concentrations. Calculated biomagnification factors (BMF( ) = C(F) /C(D) , lipid weight) of OCPs in farmed salmon typically ranged between two to five. Biomagnification of chemicals such as DDTs, chlordanes, and mirex was anticipated, as those compounds tend to exhibit high dietary uptake and slow depuration rates in fish due to relatively high octanol-water partition coefficients (K(OW) s > 10(5) ). Surprisingly, less hydrophobic pesticides such as hexachlorocyclohexanes and endosulfans (K(OW) s < 10(5) ) consistently exhibited a high degree of biomagnification in farmed salmon species (BMFs > 5). This is contrary to previous laboratory and field observations demonstrating fish BMFs < 1 for low K(OW) chemicals, due to efficient respiratory elimination of those compounds via gills. The results suggest that ambient seawater concentrations and bioconcentration driven accumulation may play a key role in the bioaccumulation of these relatively more water-soluble contaminants in farmed salmon. Lastly, OCP exposure via consumption of BC salmon is found to be low relative to United States national average per capita total exposure levels and provisional tolerable daily intakes (PTDIs). Environ. Toxicol. Chem. (c) 2011 SETAC.

Source: Kelly, B. C., M. G. Ikonomou, et al. (2011). "Flesh residue concentrations of organochlorine pesticides in farmed and wild salmon from British Columbia, Canada." Environ Toxicol Chem 2011 Aug 26. doi: 10.1002/etc.662. [Epub ahead of print].

Preconception omega-3 fatty acid supplementation of adult male mice with a history of developmental 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure prevents preterm birth in unexposed female partners

We have recently reported that adult male C57BL/6 mice exposed in utero to the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) confer an increased risk of preterm birth (PTB) to unexposed females. Risk of PTB was coincident with decreased placental progesterone receptor (Pgr) mRNA expression and increased toll-like receptor 4 (Tlr4) mRNA expression, suggesting that toxicant exposure induced a heightened inflammatory response at the maternal-fetal interface. Since omega-3 fatty acids exhibit anti-inflammatory activity, in this study, we provided TCDD-exposed males a fish oil-enriched diet prior to mating. Although PTB was common in control females mated to TCDD-exposed males on the standard diet, fish oil supplementation of TCDD-exposed males eliminated PTB in unexposed partners. We also determined the influence of preconception, paternal fish oil supplementation on the placental inflammatory response in late pregnancy (E18.5) by examining the expression of Pgr and Tlr4 mRNA as well as the expression of 15-hydroxyprostaglandin dehydrogenase (PGDH). PGDH catabolizes the inflammatory PGE2 to an inactive form; thus, reduced expression of this enzyme would promote tissue inflammation. Compared with control pregnancies, examination of E18.5 placentas arising from TCDD-exposed males on the standard diet revealed a significant increase in Tlr4 mRNA expression corresponding to a reduction in Pgr mRNA and PGDH protein expression. In contrast, fish oil supplementation of toxicant-exposed males led to normalization of placental expression of both Pgr and Tlr4 mRNA and a marked increase in PGDH expression. These studies suggest that a paternal preconception diet that includes omega-3 fatty acids prevents the toxicant-associated increase in the placental inflammatory response at late gestation, preventing PTB.

Source: McConaha, M. E., T. Ding, et al. (2011). "Preconception omega-3 fatty acid supplementation of adult male mice with a history of developmental 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure prevents preterm birth in unexposed female partners." Reproduction 142(2): 235-241.

Using river distance and existing hydrography data can improve the geostatistical estimation of fish tissue mercury at unsampled locations

Mercury in fish tissue is a major human health concern. Consumption of mercury-contaminated fish poses risks to the general population, including potentially serious developmental defects and neurological damage in young children. Therefore, it is important to accurately identify areas that have the potential for high levels of bioaccumulated mercury. However, due to time and resource constraints, it is difficult to adequately assess fish tissue mercury on a basin wide scale. We hypothesized that, given the nature of fish movement along streams, an analytical approach that takes into account distance traveled along these streams would improve the estimation accuracy for fish tissue mercury in unsampled streams. Therefore, we used a river-based Bayesian Maximum Entropy framework (river-BME) for modern space/time geostatistics to estimate fish tissue mercury at unsampled locations in the Cape Fear and Lumber Basins in eastern North Carolina. We also compared the space/time geostatistical estimation using river-BME to the more traditional Euclidean-based BME approach, with and without the inclusion of a secondary variable. Results showed that this river-based approach reduced the estimation error of fish tissue mercury by more than 13% and that the median estimate of fish tissue mercury exceeded the EPA action level of 0.3 ppm in more than 90% of river miles for the study domain.

Source: Money, E. S., D. K. Sackett, et al. (2011). "Using river distance and existing hydrography data can improve the geostatistical estimation of fish tissue mercury at unsampled locations." Environ Sci Technol 45(18): 7746-7753.

Circulating long-chain omega-3 fatty acids and incidence of congestive heart failure in older adults: the cardiovascular health study: a cohort study

BACKGROUND: Few previous studies have evaluated associations between long-chain omega-3 fatty acids and incidence of congestive heart failure (CHF), and those that have are typically based on diet questionnaires and yield conflicting results. Circulating fatty acid concentrations provide objective biomarkers of exposure. OBJECTIVE: To determine whether plasma phospholipid concentrations of long-chain omega-3 fatty acids, including eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA), were associated with incident CHF. DESIGN: Prospective cohort study. Setting: 4 U.S. communities. PATIENTS: 2735 U.S. adults without prevalent heart disease who were enrolled in the Cardiovascular Health Study from 1992 to 2006. MEASUREMENTS: Plasma phospholipid fatty acid concentrations and other cardiovascular risk factors were measured in 1992 by using standardized methods. Relationships with incident CHF (555 cases during 26 490 person-years, adjudicated by using medical records) were assessed by using Cox proportional hazards models. RESULTS: After multivariate adjustment, plasma phospholipid EPA concentration was inversely associated with incident CHF; risk was approximately 50% lower in the highest versus the lowest quartile (hazard ratio [HR], 0.52 [95% CI, 0.38 to 0.72]; P for trend = 0.001). In similar analyses, trends toward lower risk were seen for DPA (HR, 0.76 [CI, 0.56 to 1.04]; P for trend = 0.057) and total long-chain omega-3 fatty acids (HR, 0.70 [CI, 0.49 to 0.99]; P for trend = 0.062) but not for DHA (HR, 0.84 [CI, 0.58 to 1.21]; P for trend = 0.38). In analyses censored to the middle of follow-up (7 years) to minimize exposure misclassification over time, multivariate-adjusted HRs were 0.48 for EPA (CI, 0.32 to 0.71; P for trend = 0.005), 0.61 for DPA (CI, 0.39 to 0.95; P for trend = 0.033), 0.64 for DHA (CI, 0.40 to 1.04; P for trend = 0.057), and 0.51 for total omega-3 fatty acids (CI, 0.32 to 0.80; P for trend = 0.003). LIMITATIONS: Temporal changes in fatty acid concentrations over time may have caused underestimation of associations. Unmeasured or imperfectly measured covariates may have caused residual confounding. CONCLUSION: Circulating individual and total omega-3 fatty acid concentrations are associated with lower incidence of CHF in older adults. PRIMARY FUNDING SOURCE: National Institutes of Health.

Source: Mozaffarian, D., R. N. Lemaitre, et al. (2011). "Circulating long-chain omega-3 fatty acids and incidence of congestive heart failure in older adults: the cardiovascular health study: a cohort study." Ann Intern Med 155(3): 160-170.

Mercury bioaccumulation and biomagnification in Ozark stream ecosystems

Crayfish (Orconectes spp.), Asian clam (Corbicula fluminea), northern hog sucker (hog sucker; Hypentelium nigricans), and smallmouth bass (smallmouth; Micropterus dolomieu) from streams in southeastern Missouri (USA) were analyzed for total mercury (HgT) and for stable isotopes of carbon (delta(13)C), nitrogen (delta(15)N), and sulfur (delta(34)S) to discern Hg transfer pathways. HgT concentrations were generally lowest in crayfish (0.005-0.112µg/gdw) and highest in smallmouth (0.093-4.041µg/gdw), as was delta(15)N. HgT was also lower and delta(15)N was higher in all biota from a stream draining a more heavily populated historical lead-zinc mining area than from similar sites with mostly undeveloped forested watersheds. delta(13)C in biota was lowest at spring-influenced sites, reflecting CO(2) inputs and temperature influences, and delta(34)S increased from south to north in all taxa. However, HgT was not strongly correlated with either delta(13)C or delta(34)S in biota. Trophic position (TP) computed from crayfish delta(15)N was lower in hog suckers (mean=2.8) than in smallmouth (mean=3.2), but not at all sites. HgT, delta(13)C, delta(34)S, and TP in hog suckers increased with total length (length) at some sites, indicating site-specific ontogenetic diet shifts. Changes with length were less evident in smallmouth. Length-adjusted HgT site means in both species were strongly correlated with HgT in crayfish (r(2)=0.97, P<0.01), but not with HgT in Corbicula (r(2)=0.02, P>0.05). ANCOVA and regression models incorporating only TP and, for hog suckers, length, accurately and precisely predicted HgT concentrations in both fish species from all locations. Although low compared to many areas of the USA, HgT (and therefore methylmercury) concentrations in smallmouth and hog suckers are sufficiently high to represent a threat to human health and wildlife. Our data indicate that in Ozark streams, Hg concentrations in crayfish are at least partly determined by their diet, with concentrations in hog suckers, smallmouth, and possibly other higher-level consumers largely determined by concentrations in crayfish and other primary and secondary consumers, fish growth rates, and TP.

Source: Schmitt, C. J., C. A. Stricker, et al. (2011). "Mercury bioaccumulation and biomagnification in Ozark stream ecosystems." Ecotoxicol Environ Saf 2011 Aug 23. [Epub ahead of print].

Fish, shellfish, and long-chain n-3 fatty acid consumption and risk of incident type 2 diabetes in middle-aged Chinese men and women

BACKGROUND: Long-chain polyunsaturated n-3 (omega-3) fatty acids, found mainly in fish, have been postulated to reduce type 2 diabetes (T2D) risk. However, the role of long-chain n-3 fatty acids and fish intake in the development of T2D remains unresolved. OBJECTIVE: We examined associations between fish, shellfish, and long-chain n-3 fatty acids and the risk of T2D in a middle-aged Chinese population. DESIGN: This was a prospective population-based cohort study in 51,963 men and 64,193 women free of T2D, cardiovascular disease, and cancer at baseline with valid dietary information. Dietary intake, physical activity, and anthropometric measurements were collected. A Cox regression model was used to evaluate the association of fish, shellfish, and long-chain n-3 fatty acid (in g/d) with risk of T2D. RESULTS: Fish, shellfish, and long-chain n-3 fatty acid intakes were inversely associated with T2D in women. The relative risks [RRs (95% CI)] for quintiles of fish intake were 1.00, 0.96 (0.86, 1.06), 0.84 (0.75, 0.94), 0.80 (0.71, 0.90), and 0.89 (0.78, 1.01) (P for trend = 0.003) and for shellfish were 1.00, 0.91 (0.82, 1.01), 0.79 (0.71, 0.89), 0.80 (0.71, 0.91), and 0.86 (0.76, 0.99) (P for trend = 0.006). In men, only the association between shellfish intake and T2D was significant. The RRs (95% CI) for quintiles of fish intake were 1.00, 0.92 (0.75, 1.13), 0.80 (0.65, 1.00), 0.89 (0.72, 1.11), and 0.94 (0.74, 1.17) (P for trend = 0.50) and for shellfish intake were 1.00, 0.93 (0.76, 1.12), 0.70 (0.56, 086), 0.66 (0.53, 0.82), and 0.82 (0.65, 1.02) (P for trend = 0.003). CONCLUSIONS: An inverse association between fish and shellfish intake and T2D in women was found. No evidence of a detrimental effect of fish intake in this population was observed.

Source: Villegas, R., Y. B. Xiang, et al. (2011). "Fish, shellfish, and long-chain n-3 fatty acid consumption and risk of incident type 2 diabetes in middle-aged Chinese men and women." Am J Clin Nutr 94(2): 543-551.

Fish oil, selenium and mercury in relation to incidence of hypertension: a 20-year follow-up study

OBJECTIVES: Long-chain omega-3 polyunsaturated fatty acids (LComega3PUFAs), selenium (Se) and mercury (Hg) are three important components in fish. The cardioprotective effect of LComega3PUFA intake has been recognized; however, the hypothesis that this benefit may be greatest with high Se and low Hg levels has not been investigated. DESIGN: A cohort of 4508 American adults aged 18-30, without hypertension at baseline in 1985, were enrolled. Six follow-ups were conducted at examinations in 1987, 1990, 1992, 1995, 2000 and 2005. Diet was assessed by a validated interviewer-administered quantitative food frequency questionnaire at exams in 1985, 1992 and 2005. Incident hypertension was defined as first occurrence at any follow-up examination of systolic blood pressure (BP) >/= 140 mmHg, diastolic BP >/= 90 mmHg or taking antihypertensive medication. Toenail clippings were collected in 1987, and Se and Hg levels were quantified by instrumental neutron-activation analysis. RESULT: Participants in the highest LComega3PUFA intake quartile had a significantly lower incidence of hypertension (hazard ratio: 0.65; 95% CI: 0.53-0.79; P(trend) < 0.01) compared to those in the lowest quartile after adjustment for potential confounders. Docosahexaenoic acid showed a greater inverse association than eicosapentaenoic acid. The inverse association of LComega3PUFA intake with hypertension appeared more pronounced at higher Se and lower Hg levels, although interaction tests were statistically nonsignificant. CONCLUSIONS: Our findings indicated that LComega3PUFA intake was inversely associated with incidence of hypertension. The prior hypothesis that the potential antihypertensive effect of LComega3PUFA intake varies depending on joint levels of Se and Hg received modest support and cannot be ruled out.

Source: Xun, P., N. Hou, et al. (2011). "Fish oil, selenium and mercury in relation to incidence of hypertension: a 20-year follow-up study." J Intern Med 270(2): 175-186.

The following recent publications are also of interest, but the abstracts are not reprinted here due to copyright restrictions:

Selenium moderates mercury toxicity in free-ranging freshwater fish.
Sørmo, E. G. E. G., T. M. T. M. Ciesielski, et al. (2011). Environmental Science & Technology 45(15): 6561-6566.

An approach for quantitatively balancing methylmercury risk and omega-3 benefit in fish consumption advisories.
Stern, A. H. A. H. and L. R. L. R. Korn (2011). Environmental Health Perspectives 119(8): 1043-1046.

Meetings and Conferences

International Society of Exposure Science (ISES) - 21st Annual Meeting
October 23-27, 2011 Baltimore, Maryland
14th World Lake Conference
October 31-November 4, 2011 Austin, Texas
The Society of Environmental Toxicology and Chemistry (SETAC) North America 32nd Annual Meeting
November 13-17 2011, Boston, Massachusetts
Society for Risk Analysis Annual Meeting
December 4-7, 2011 Charleston, South Carolina

For More Information

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