Newsletter - September 2004
Note: The following summaries are based on articles from the press and from peer-reviewed publications, and they represent the opinions of the original authors. The views of authors expressed herein do not necessarily state or reflect those of the United States Government, and shall not be used for advertising or product endorsement purposes. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government.
Recent Advisory News
- Florida health officials may issue mercury warning on popular saltwater fish. Advisories proposed by officials in the Florida Department of Health would recommend limiting consumption of dolphin, pompano, red snapper and many other species. Contained in the draft version of a guide to Florida seafood, the advisories would add 40 saltwater species to the warning list, along with freshwater lakes, streams and other bodies of water where consumption of fish should be limited. The recommendations range from avoiding certain fish entirely to restricting consumption to one a month, two a week and so on. Jackie DiPietre, spokeswoman for the Health Department, stressed that the list of advisories was only a draft and could easily change before the department issued the final version.
Source: David Fleshler. Florida Sun-Sentinel, August 31, 2004.
- Advisories set for Miss. waterways. The Mississippi Department of Environmental Quality has issued advisories limiting consumption of some fish caught in Mississippi waters. Approximately one-third of the lakes and one-forth of the rivers contain enough pollution that people should limit or altogether avoid consumption of fish from these waters. "All waters in Mississippi have advisories for mercury which recommend only one meal per week of fish caught in contaminated waters," said Henry Folmar, who is the laboratory director for the MDEQ. The Mississippi State Health Department recommends that children under the age of seven and women of child-bearing age eat no more than one meal of large-mouth bass and catfish larger than 27 inches every two months if caught in the Enid Reservoir. For all other adults, the recommended intake is one meal every two weeks. Also, Lake Susie, located near Grenada, had been found to be contaminated with PCB.
Source: Carly Dickson, The Daily Mississippian, August 31, 2004.
- High level of PCBs found in Lake Washington fish. Washington state health officials found higher than expected levels of PCBs in Lake Washington fish, prompting them to issue new advisories. People should not eat large perch or cutthroat, which are among the most commonly caught fish in the lake, more than once a month, officials said. For cutthroat under 12 inches, the recommended maximum is three meals a month, and for perch under 10½ inches, no more than four meals monthly. The Washington Department of Health also warned people never to eat the lake's northern pikeminnow, also known as squawfish. Though not favored by many anglers, pikeminnows collected in the lake contained up to 1,000 parts per billion (ppb) of PCBs - the highest level ever measured in any Washington fish species, said health department toxicologist Dave McBride.
Source: Sandi Doughton. The Seattle Times, September 1, 2004.
- Study Cites High Levels of Chemical Fire Retardants (PBDEs) in Farmed Salmon. Farmed salmon accumulate higher levels of chemical flame retardants (PBDEs) than wild salmon, according to a study published in the journal Environmental Science and Technology. The levels of flame retardants varied according to where the fish was farmed. European farmed salmon had higher amounts of PBDEs than North American salmon; Chilean farmed salmon had the least. Researchers sampled 700 farmed and wild salmon bought from wholesale suppliers as well as supermarkets. Levels in farmed salmon ranged between 1 and 4 parts per billion, while wild salmon showed concentrations on average of 0.5 parts per billion. The difference between wild and farmed salmon stems from their diet, researchers wrote: "Farmed salmon are fed a concentrated feed high in fish oils and fish meal, which is obtained primarily from small pelagic fishes."
Source: Juliet Eilperin. Farmed Salmon Raise Concerns Study Cites High Levels of Chemical Fire Retardants. Washington Post, Wednesday, August 11, 2004; Page A03
- Species differences in contaminants in fish on and adjacent to the Oak Ridge Reservation, Tennessee. In this report the authors examine the concentrations of (137)Cs, arsenic, beryllium, cadmium, lead, mercury, and selenium in three species of fish from two river reaches adjacent to the US Department of Energy's Oak Ridge Reservation in Tennessee. Lead was significantly lower in striped bass, mercury was significantly higher in striped bass, and selenium was significantly higher in white bass compared to the other species. There were no other species differences in contaminants. White bass, the only species that was sufficiently abundant for a comparison, had significantly higher concentrations of cadmium, lead, and selenium in fillets from the Clinch River and significantly higher concentrations of mercury in fillets from Poplar Creek. The low concentrations of most contaminants in fish from the Clinch River do not appear to present a risk to humans or other consumers, although mercury concentrations in striped bass ranged as high as 0.79ppm, well above the 0.5-ppm action level for human consumption of some US states.
Source: Burger J, Campbell KR. Environ Res 2004 Oct;96(2):145-55.
- Mercury in fish from the Pinchi Lake Region, British Columbia, Canada. Water, surface sediments, and <40 cm rainbow trout and northern pikeminnow were collected from Pinchi Lake, British Columbia, and from several nearby reference lakes. Hg concentrations in sediment samples from Pinchi L. were highly elevated compared to sediments from reference lakes, especially in sites adjacent to and downstream of a former Hg mine. Hg concentrations in both fish species were highest in Pinchi L., and were higher in pikeminnow than in rainbow trout of similar size. Average Hg concentrations in small rainbow trout from all lakes, including Pinchi L., were lower than dietary levels reported to cause reproductive impairment in common loons; however, Hg levels in small pikeminnow from Pinchi L. were sufficiently high to be of concern. The risk for Hg toxicity in the study area is greatest for animals that consume larger piscivorous fish such as larger northern pikeminnow or lake trout, which are known from previous studies to contain higher Hg concentrations.
Source: Weech SA, Scheuhammer AM, Elliott JE, Cheng KM. Environ Pollut 2004 Sep;131(2):275-86.
- Maternal and fetal mercury and n-3 polyunsaturated fatty acids as a risk and benefit of fish consumption to fetus. In this study the authors examined the relationships between blood mercury levels and plasma fatty acid composition in mother and fetus at birth. Venous blood samples were collected from 63 pairs of mothers and fetuses (umbilical cord blood. In all cases, fetal RBC-Hg levels were higher than maternal RBC-Hg levels. While the average fetal/maternal RBC-Hg ratio was 1.6, the individual ratios varied from 1.08 to 2.19, suggesting considerable individual differences in MeHg concentrations between maternal and fetal circulations at delivery. A significant correlation was observed between maternal and fetal DHA concentrations (r = 0.37, p < 0.01). Further, a significant correlation was observed between RBC-Hg and plasma DHA in fetus (r = 0.35, p < 0.01). These results confirm that both MeHg and DHA which originated from fish consumption transferred from maternal to fetal circulation and existed in the fetal circulation with a positive correlation. The authors feel that pregnant women in particular need not give up eating fish to obtain such benefits; however, they might consume smaller fish, which contain less MeHg, thereby balancing the risks and benefits from fish consumption.
Source: Sakamoto M, Kubota M, Liu XJ, Murata K, Nakai K, Satoh H. Environ Sci Technol 2004 Jul 15;38(14):3860-3.
- Association between mercury concentrations in blood and hair in methylmercury-exposed subjects at different ages. Mercury concentrations were measured in paired hair and blood samples from a cohort of about 1,000 children examined at birth and at 7 and 14 years of age. The ratio between concentrations in maternal hair (in microg/g) and in cord blood (microg/L) was approximately 200, but samples from the children at age 14 years showed a ratio of about 250. These findings are in accordance with previous data from smaller studies. However, an even higher ratio of about 360 was seen at 7 years of age, suggesting that hair strands at this age retain more mercury. The 95th percentile of the hair-to-blood ratio was between five-fold and nine-fold greater than the 5th percentile. The results were examined in structural equation models to estimate the total imprecision of the individual biomarker results and the possibility that the ratio may not be constant. The hair-to-blood ratio was found to increase at lower mercury concentrations, a tendency that could not be explained by potential confounders, such as alcohol intake or number of amalgam fillings. The total imprecision (coefficient of variation) for the blood determinations averaged about 30%, thereby substantially exceeding normal laboratory imprecision. Yet hair-mercury results had an even greater imprecision, which suggested that preanalytical factors, such as variable sample characteristics, impacted the results. These findings are in accordance with other evidence that the cord blood concentration is a better predictor of neurobehavioral toxicity than is the maternal hair concentration. Although practical for field studies and monitoring purposes, hair-mercury concentration results, therefore, need to be calibrated and interpreted in regard to each specific study setting.
Source: Budtz-Jorgensen E, Grandjean P, Jorgensen PJ, Weihe P, Keiding N. Environ Res 2004 Jul;95(3):385-93.
- Temporal variation of blood and hair mercury levels in pregnancy in relation to fish consumption history in a population living along the St. Lawrence River. The goal of this study was to characterize the temporal variation of Hg during pregnancy and to investigate the relation between fish consumption from various sources prior to and during pregnancy and maternal cord blood and mother's hair Hg levels. The authors recruited 159 pregnant women from Southwest Quebec through two prenatal clinics of the Quebec Public Health System. All women completed two detailed questionnaires concerning their fish consumption (species and frequency) prior to and during pregnancy. The women also provided blood samples for all three trimesters of pregnancy and hair samples after delivery of up to 9 cm in length. Blood and hair Hg levels were analyzed by cold-vapor atomic-absorption and -fluorescence spectrometry methods, respectively. Results showed that maternal blood and hair Hg levels decreased significantly between the second and third trimesters of pregnancy. However, cord blood Hg was significantly higher than maternal blood at birth. Maternal hair was correlated with Hg blood concentration and was highly predictive of the organic fraction in cord blood. A strong dose relation was observed between the frequency of fish consumption before and during pregnancy and Hg exposure in mothers and newborns. Fish consumption prior to and during pregnancy explained 26% and 20% of cord blood Hg variance, respectively. For this population, detailed multivariate analyses showed that during pregnancy market fish (fresh, canned, and frozen) were more important sources of Hg exposure than were fish from the St. Lawrence River. The authors feel that these results should be taken into account for future advisories and intervention strategies, which should consider Hg levels in different species from all sources in order to maximize the nutritional input from fish and minimize the toxic risk.
Source: Morrissette J, Takser L, St-Amour G, Smargiassi A, Lafond J, Mergler D. Environ Res 2004 Jul;95(3):363-74.
- Exposure assessment and initial intervention regarding fish consumption of tribal members of the Upper Great Lakes Region in the United States. The Ojibwe Health Study (OHS) has concluded 10 years of data collection and exposure assessment. Eight hundred and twenty-two participants from tribes in the states of Wisconsin, Michigan, and Minnesota completed fish consumption and environmental risk perception questionnaires. Many participants provided hair and blood samples for mercury and PCB residue analyses. Fish were collected by the tribal organizations and contaminants were analyzed for numerous tribal reports and professional environmental journal articles. These data were used by the Great Lakes Indian Fish and Wildlife Commission (GLIFWC) to produce tribal-specific geographic information systems maps as part of a public health intervention strategy. The Great Lakes Inter-Tribal Council provided the OHS and each participating tribe in Wisconsin and Michigan with a health profile. Total fish consumption (estimated by recall) for 720 tribal participants was self-reported as 60 g/day, but the highest actual consumption was measured as 11.2 g/day in one of the tribal groups. The highest blood concentrations in tribal participants were 18.6 ppb total serum PCBs and 11.8 ppb total blood mercury. Ninety percent of the participants had less than 3.8 ppb total serum PCBs and 2.6 ppb total blood mercury. Compared to other studies of subsistence fishing populations, these exposures were only moderately elevated and not high enough to warrant widespread restrictions on diets. Furthermore, the benefits of eating a fish diet must be continually emphasized. However, sport fishermen and their families who consume larger and more contaminated fish should abide by their state fish consumption advisories to minimize their health risks.
Source: Dellinger JA. Environ Res 2004 Jul;95(3):325-40.
- Blood mercury levels among Ontario anglers and sport-fish eaters. The authors conducted two surveys of Ontario (Canada) fishers: a stratified sample of licensed anglers in two Lake Ontario communities (n=232) and a shore and community-based sample in five Great Lakes' Areas of Concern (n=86). Among the 176 anglers consuming their catch, the median number of sport-fish meals/year was 34.2 meals and 10.9, respectively, in two communities, with a mean blood total mercury level among these sport-fish consumers of 2.8 microg/L. The vast majority of fish eaten by AOC eaters was from Ontario waters (74%). For AOC eaters, two broad country-of-origin groups were assembled: Euro-Canadians (EC) and Asian-Canadians (AC). EC consumed a median of 174 total fish meals/year and had a geometric mean total mercury level of 2.0 microg/L. Corresponding AC figures were 325 total fish meals/year and 7.9 microg/L. Overall, mercury levels among AOC eaters were higher than in many other Great Lakes populations but lower than in populations frequently consuming seafood. In multivariate models, mercury levels were significantly associated with levels of fish consumption among both anglers and EC AOC eaters. The authors state that given the nutritional and social benefits of fish consumption, informed species and location choices should continue.
Source: Cole DC,Kearney J, Sanin LH, Leblanc A, Weber JP. Environ Res 2004 Jul;95(3):305-14.
- Accumulation and distribution of polychlorinated dibenzo-p-dioxin, dibenzofuran, and polychlorinated biphenyl congeners in Atlantic salmon. For this study, adult Atlantic salmon were fed on four diets containing polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) for 30 weeks. Lipid-normalized concentrations showed that all congeners were equally partitioned between whole-fish and fillet samples. Skinned fillet accumulated approximately 30% of the total PCDD/F and PCB content in fish. Accumulation efficiencies in whole fish were 43% for 2,3,7,8-chlorinated dibenzo-p-dioxins and dibenzofurans, 83% for dioxin-like PCBs, and 78% for other PCB congeners. Among PCDD/Fs, tetra- and pentachlorinated congeners were preferentially accumulated in salmon, whereas hepta- and octachlorinated dibenzo-p-dioxins were excreted in the feces. Substitution patterns that were associated with a preferential accumulation of PCBs in salmon included non-ortho substitution and tetrachlorination. Accumulation efficiencies and lipid-normalized biomagnification factors (BMFs) were not influenced by the PCDD/F and PCB concentrations of the diets. Biomagnification (BMF > 1) of tetra- and pentachlorinated dibenzo-p-dioxins and dibenzofurans and of all the PCBs was observed. Differences in the behavior of PCDD/F and PCB congeners resulted in a selective enrichment of the most toxic congeners in salmon
Source: Isosaari P, Kiviranta H, Lie O, Lundebye AK, Ritchie G, Vartiainen T. Environ Toxicol Chem 2004 Jul;23(7):1672-9.
Meetings and Conferences
- Fourth SETAC World Congress
The Society of Environmental Toxicology and Chemistry (SETAC) will hold the Fourth SETAC World Congress and the 25th Annual Meeting for North America concurrently in Portland, OR November 14-18, 2004. The theme for the Fourth SETAC World Congress is "SETAC: 25 Years of Interdisciplinary Science Serving Global Society 1979 - 2004" For more information visit the website: www.setac.org/portland.html.
Please email the newsletter (email@example.com) if you would like to announce an upcoming meeting, conference, or to submit an article.