Effect of freeze–thaw cycles on total and heme iron contents of bonito (Sarda sarda) and bluefish (Pomatomus saltator) fillets

The effects of the number of freeze–thaw cycles on total and heme iron contents of bonito (Sarda sarda) and bluefish (Pomatomus saltator) fillets were investigated. The prepared fillets were packaged in polyethylene bags, the bags were heat sealed and than these samples were subjected to a total of 5 freeze–thaw cycles. Effects of freeze–thaw cycles on total and heme iron content of bonito and bluefish fillets were statistically significant (P<0.05). The total and heme iron contents of both fishes decreased as the number of freeze–thaw cycles increased, and the highest losses were found after the second freeze–thaw cycle. Total and heme iron losses were higher in bluefish fillet. The multiple freeze–thaw process therefore is not suitable in terms of total and heme iron contents.     

The effect of mercury on the feeding behavior of fathead minnows (Pimephales promelas)

Fathead minnows (Pimephales promelas) were exposed to mercury (1.69, 6.79, and 13. 57 microg/L HgCl(2), 10 days exposure), and afterward their foraging ability was tested in a vegetated habitat for 7 days. Among the foraging metrics used were foraging efficiency, capture speed, and the ability to learn and retain information regarding habitat characteristics. In addition to behavioral tests, muscle tissue acetylcholinesterase activity and brain levels of several neurotransmitters were investigated. Comparisons with control fish and fish from the two highest exposure groups revealed consistent performance deficits in foraging efficiency and capture speed. However, no treatment effects on learning were detected, nor were differences in neurotransmitter levels detected. In determining the underlying proximate cause of the foraging deficits, it is believed that the greater pause time exhibited by treatment fish while foraging was the main cause of treatment differences. In the future, behavioral studies will continue to allow toxicity testing of environmentally relevant variables such as those used by behavioral ecologists.     

Monitoring Programme on Toxic Metal in Bluefish (Pomatomus saltatrix), Anchovy (Engraulis encrasicolus) and Sardine (Sardina pilchardus) from Istanbul, Turkey: Levels and Estimated Weekly Intake

Toxic metal (Hg, Cd, Pb, Cu and Zn) concentrations of small-medium bluefish, anchovy and sardine in Istanbul, Turkey, were determined using inductively coupled plasma-mass spectrometry (ICP-MS) throughout 1 year. The concentrations of pollutants were found to vary according to season and species. Estimates of weekly intake levels of the metals were calculated and compared to recommended safe limits for fish consumption by humans. The levels of Cd, Pb, Cu and Zn in the fillets of all species resulted in estimates of weekly intake levels that were lower than the recommended safe limits. The concentrations of Hg of small bluefish in September, of medium bluefish in June and September, of anchovy in March, and of sardine in August and September resulted in estimates of weekly intake levels that were higher than the recommended safe limits for human consumption.     

Influence of feeding ecology on blood mercury concentrations in four species of turtles

Mercury is a relatively well-studied pollutant because of its global distribution, toxicity, and ability to bioaccumulate and biomagnify in food webs: however, little is known about bioaccumulation and toxicity of Hg in turtles. Total Hg (THg) concentrations in blood were determined for 552 turtles representing four different species (Chelydra serpentina, Sternotherus odoratus, Chrysemys picta, and Pseudemys rubriventris) from a Hg-contaminated site on the South River (VA, USA) and upstream reference sites. Methylmercury and Se concentrations also were determined in a subset of samples. Because the feeding ecology of these species differs drastically, stable isotopes of carbon (delta13C) and nitrogen (delta15N) were employed to infer the relationship between relative trophic position and Hg concentrations. Significant differences were found among sites and species, suggesting that blood can be used as a bioindicator of Hg exposure in turtles. We found differences in THg concentrations in turtles from the contaminated site that were consistent with their known feeding ecology: C. serpentina > or = S. odoratus > C. picta > P. rubriventris. This trend was generally supported by the isotope data, which suggested that individual turtles were feeding at more than one trophic level. Methylmercury followed similar spatial patterns as THg and was the predominant Hg species in blood for all turtles. Blood Se concentrations were low in the system, but a marginally positive relationship was found between THg and Se when species were pooled. The blood THg concentrations for the turtles in the present study are some of the highest reported in reptiles, necessitating further studies to investigate potential adverse effects of these high concentrations.     

Evaluating mercury biomagnification in fish from a tropical marine environment using stable isotopes (delta13C and delta15N)

Concentrations of total mercury (T-Hg) and methylmercury (MeHg) were measured in zooplankton and 13 fish species from a coastal food web of the Gulf of Oman, an arm of the Arabian Sea between Oman and Iran. Stable isotope ratios (delta13C and delta15N) also were determined to track mercury biomagnification. The average concentration of T-Hg in zooplankton was 21 +/- 8.0 ng g(-1) with MeHg accounting 10% of T-Hg. Total mercury levels in fish species ranged from 3.0 ng g(-1) (Sardinella longiceps) to 760 ng g(-1) (Rhizoprionodon acutus) with relatively lower fraction of MeHg (72%) than that found in other studies. The average trophic difference (Deltadelta13C) between zooplankton and planktivorous fish (Selar crumenopthalmus, Rastrelliger kanagurta, and S. longiceps) was higher (3.4 per thousandth) than expected, suggesting that zooplankton may not be the main diet or direct carbon source for these fish species. However, further sampling would be required to compensate for temporal changes in zooplankton and the influence of their lipid content. Trophic position inferred by delta15N and and slopes of the regression equations (log10[T-Hg] = 0.13[delta15N] - 3.57 and log10[MeHg] = 0.14[delta15N] - 3.90) as estimates of biomagnification indicate that biomagnification of T-Hg and MeHg was lower in this tropical ocean compared to what has been observed in arctic and temperate ecosystems and tropical African lakes. The calculated daily intake of methylmercury in the diet of local people through fish consumption was well below the established World Health Organization (WHO) tolerable daily intake threshold for most of the fish species except Euthynnus affinis, Epinephelus epistictus, R. acutus, and Thunnus tonggol, illustrating safe consumption of the commonly consumed fish species.     

Risk to consumers from mercury in bluefish (Pomatomus saltatrix) from New Jersey: Size, season and geographical effects

Relatively little attention has been devoted to the risks from mercury in saltwater fish, that were caught by recreational fisherfolk. Although the US Food and Drug Administration has issued advisories based on mercury for four saltwater species or groups of fish, there are few data on how mercury levels vary by size, season, or location. This paper examines total mercury levels in muscle of bluefish (Pomatomus saltatrix) collected from coastal New Jersey, mainly by recreational fishermen. Of primary interest was whether there were differences in mercury levels as a function of location, weight and length of the fish, and season, and in what risk mercury posed to the food chain, including people. Selenium was also measured because of its reported protective effects against mercury. Mercury levels averaged 0.35±0.02 (mean and standard error) ppm, and selenium levels averaged 0.37±0.01 ppm (N=206). In this study, 41% of the fish had mercury levels above 0.3 ppm, 20% had levels above 0.5 ppm, and 4% had levels above 1 ppm. Size was highly correlated with mercury levels, but not with selenium. While selenium levels did not vary at all with season, mercury levels decreased significantly. This relationship was not due to differences in the size of fish, since the fish collected in the summer were the smallest, but had intermediate mercury levels. Mercury levels declined from early June until November, particularly for the smaller-sized fish. While there were significant locational differences in mercury levels (but not selenium), these differences could be a result of size. The levels of mercury in bluefish are not sufficiently high to cause problems for the bluefish themselves, based on known adverse health effects levels, but are high enough to cause potential adverse health effects in sensitive birds and mammals that eat them, and to provide a potential health risk to humans who consume them. Fish larger than 50 cm fork length averaged levels above 0.3 ppm, suggesting that eating them should be avoided by pregnant women, children, and others who are at risk.     

Historical and other patterns of monomethyl and inorganic mercury in the Florida panther (Puma concolor coryi)

Since the late 1980s, elevated levels of mercury have been reported in the tissues of the Florida panther (Puma concolor coryi) from the Florida Everglades. The extent, degree, and length of time of mercury contamination in the Florida panther are unknown. The objective of this study was to determine the historical and other patterns of monomethyl and inorganic mercury in the Florida panther by analysis of mercury in panther hair from museum collections. In addition, this study evaluated the effects of preservation of skins on mercury concentrations in hair and the representativeness of museum collections for evaluating historical trends of contamination in the Florida panther. Hair from 42 Florida panther specimens collected from 1896 to 1995 was analyzed for both monomethyl and inorganic mercury. Monomethyl mercury (MMHg) and inorganic mercury (IHg) were found in all specimens. Monomethyl mercury in hair from untanned skins was significantly higher than MMHg in hair from tanned skins. For untanned specimens, the mean MMHg concentration in hair was 1.62 +/- 1.87 mug/g (range 0.11 to 6.68 mug/g, n = 16). Monomethyl mercury accounted for 88% of the total mercury in untanned Florida panther hair. No sexual or geographical differences were found. Although MMHg is generally stable in hair, the tanning process appears to reduce the amount of MMHg in hair. In addition, exogenous IHg contamination of the panther hair was found in museum specimens, especially in older specimens. The implication of these and other factors in interpreting results of museum studies is discussed. The presence of MMHg in panther hair since the 1890s indicates long-term and widespread exposure of the Florida panther to mercury. Levels of MMHg are significantly greater in the 1990s than the 1890s. When combined with field studies of mercury in the Florida panther, considerable individual variability is observed, reflecting short-term changes in exposure of individual panthers to mercury. Although museum specimens showed a significant increase in MMHg over the last 100 years, they did not show the magnitude of increase that field populations of Florida panthers did. A number of Florida panthers appeared to be at risk from mercury over their lifetimes, especially individuals from the early 1990s.     

The teratogenic effect of zinc deficiency and accompanying feeding patterns in mice

The effect of zinc deficiency on fetal development in rats is well established, as also is the importance of the accompanying feeding/fasting cycle on the severity of the zinc-related dysmorphology. Little is known concerning the teratogenesis of zinc deficiency in mice and nothing has been reported with respect to the feeding pattern in this species when fed a zinc-deficient diet. The present studies with pregnant mice (C57BL/6J) revealed them to be acutely sensitive to dietary zinc restriction, with the result that total loss of offspring occurred when the diet contained less than 5 ppm of zinc. Severe teratogenesis accompanied intakes of between 5 and 10 ppm of zinc, but in contrast to rats, no cyclical feeding pattern was evident in mice receiving a zinc-deficient diet, nor was food intake depressed when expressed on a body weight basis. Tissue zinc levels in mice responded to dietary zinc restriction in a manner similar to that reported for rats, with plasma and bone zinc levels being especially sensitive to the zinc intake.     

A test of the Booth energy flow model (Mark 3) on feeding patterns of mice

Booth's dynamic model is a particular realization of a general hypothesis ascribing the start and stop of rat meals to fluctuations in the value of the net energy flow entering into the lean body mass. The Mark 3 version of this model has been adapted to the mouse Mus musculus C3H. Recordings for 11.5 consecutive hours of diurnal and nocturnal sequences of feeding behaviour in six mice have made it possible to compare not only the simulated and observed ingested amounts, but also the corresponding time patterns. The results show the consistency of the energy flow hypothesis with the feeding pattern in mice. The results also show that satiety conditioning does not improve simulated patterns and indicate which modification of the model parameters allow the simulation of the observed differences between day and night patterns. Finally, detailed discrepancies between observed and simulated results suggest that the model would be improved by taking into account other behaviours liable to interact with feeding behaviour.     

Gonotrophic status, sperm presence and sugar feeding patterns in southwestern Quebec tabanid (Diptera) populations

Parity, stage of follicular development, sperm and fructose presence were determined for 6 tabanid species from southwestern Quebec during 2 consecutive years. Females were collected in canopy traps baited with or without carbon dioxide. Based on the presence or absence of host-seeking nulliparous flies (nullipars), Hybomitra epistates, H. nitidifrons nuda, H. sodalis, Tabanus lineola and T. similis were classified as being anautogenous. Hybomitra frontalis was classified as autogenous for its first ovarian cycle. Sperm was found in 88% and fructose was detected in 84% of the 700 specimens dissected. In anautogenous species, sperm and fructose prevalence was higher in pars than in nullipars.     

Histopathological evidence of inorganic mercury and methyl mercury toxicity in the arctic charr (Salvelinus alpinus)

In our sustained effort to understand mechanisms of mercury toxicity in fish, the histopathological effects of a 96-h acute exposure to water-borne inorganic mercury (inorganic Hg) (15 micro gL(-1)), as well as those of a single dietary dose of inorganic and methyl mercury (methyl Hg) (0.260.05 micro g.Hgg(-1) body weight), over 30 days were examined. Samples of gills, olfactory epithelium, kidneys, and liver of arctic charr, Salvelinus alpinus, were studied using light and electron microscopy. The distribution of dietary inorganic and methyl Hg in the intestinal epithelium was determined using 203Hg microautoradiography. Gills of fish exposed to water-borne inorganic Hg presented a severe disorganization of epithelial cells after 12h and modifications of cilia of ciliated olfactory cells appeared after 24h. Nevertheless, a partial recovery was seen in both tissues by the end of the 96-h exposure period. Liver was little affected by water-borne and single-trophic-dose contamination of inorganic Hg, but dietary methyl Hg had drastic effects, despite its low dosage, with severe necrosis and alterations of cytoplasmic organization. Microautoradiograms showed that inorganic Hg was distributed evenly in the intestinal epithelium, whereas methyl Hg was found at very specific locations on the epithelial surface.     

Exposure to heavy metals (lead, cadmium and mercury) and its effect on the outcome of in-vitro fertilization treatment

We investigated the effect of lead, cadmium and mercury exposure on pregnancy and fertilization rate outcome among 619 Saudi women (age 19-50 years) who sought in-vitro fertilization (IVF) treatment between 2002 and 2003. The concentrations of lead, cadmium and mercury were measured in both blood and follicular fluids. At levels well below the current US occupational exposure limit guidelines (40microg/dL) and even less than the current Centers for Disease Control and Prevention level of concern for preventing lead poisoning in children (10microg/dL), blood lead level was negatively associated with fertilization outcome in both adjusted and unadjusted logistic regression models. We found that among various demographic, socioeconomic and environmental factors, fish consumption was positively associated with blood lead levels. These results support the hypothesis that a raised blood lead level affects infertility and intervention to reduce the lead exposure might be needed for women of reproductive age. The present results also revealed unexpected finding - the positive relationship between follicular cadmium levels and fertilization outcome, which points to the necessity for further investigation. Though adverse effect of mercury on pregnancy outcome or fertilization rate was not evident in this study, mercury5.8microg/L (EPA safety limit) was found in the blood and follicular fluid of 18.7% and 8.3% of the women, respectively. Concerns about its possible adverse effects on the physiology of reproduction or fetal development cannot be ruled out. It should be noted that skin-lightening creams and dental amalgam were important contributors to mercury exposure. Such finding is alarming and priority for further studies are, urgently, needed.     

Statistical study of the correlation between mercury exposure (TWA) and urinary mercury concentrations in chloralkali workers

The present report completes a previous study made on three chloralkali plants that was presented at the 8th International Conference on Occupational Health in the Chemical Industry, Tokyo, 1980, with the final results from five plants located in various regions of Italy. A total of 14,339 measurements of mercury in air and 8,042 determinations of mercury in urine were considered. The total number of workers involved was 275. On the basis of these data, we believe it can be concluded that, as previously reported, a correlation exists between mercury concentrations in the air and in the urine of exposed workers. This correlation is such that for exposures in the order of the present TLV (0.05 mg/m³), the value of the Z ratio (ratio between mean urinary mercury values expressed in mg/l and mean airborne mercury concentrations expressed in mg/m³) is 1.3, while the urinary mercury values vary from 0.051 mg/l to 0.078 mg/l with a mean value of 0.065 mg/l.     

新生儿血清瘦素水平与喂养方式间的关系研究

目的:测定母乳及配方乳中瘦素含量,比较不同喂养方式对足月新生儿血清瘦素水平的影响。方法:采用放射免疫分析法测定足月新生儿血清、母乳及配方乳中的瘦素水平。结果:①66例健康足月儿生后第3、7、28天其母乳中的瘦素水平分别为(1.31±0.67)μg/L、(1.33±0.14)μg/L、(1.26±0.98)μg/L,产后不同日龄母乳中瘦素水平差异无统计学意义(F=1.78,P>0.05)。配方乳中瘦素水平为0。②母乳喂养组新生儿生后第3、7、28天血清中瘦素水平分别为(2.45±1.04)μg/L、(3.38±1.54)μg/L、(4.98±2.16)μg/L;人工喂养组新生儿生后第3、7、28天血清中瘦素水平分别为(1.23±0.67)μg/L、(1.91±0.31)μg/L、(2.63±1.19)μg/L;两组间血清瘦素水平差异显著(t=1.113,t=3.176,t=2.152,P<0.05)。结论:①母乳中含有一定浓度的瘦素,初乳与成熟乳之间瘦素水平无显著差异,配方乳中未检测到瘦素。②母乳喂养儿血清瘦素水平明显高于人工喂养儿,母乳喂养有利于维持新生儿期血中较高的瘦素水平。     

Effect of insecticides on plankton and fish of Ignacio Ramirez reservoir (Mexico): a biochemical and biomagnification study

Studies on the limnology, plankton, and biomagnification of pesticides at Ignacio Ramírez (IR) reservoir (Mexico) were undertaken. The reservoir is located in central Mexico, in an agricultural zone with high soil erosion. Acetylcholinesterase (AchE), gamma-glutamyl transpeptidase (GGTP), and lipid peroxidation were assayed in fish. Organochlorines (0.024-0.279 mg/liter) and organophosphates (0.02 x 10(-3)-0.21 x 10(-3) mg/liter) were present at high concentrations in water and the biota assayed. In the IR dam the plankton fluctuated depending on the dry and wet seasons. The dominant group of phytoplankton was Bacillariophyta (20-85%) in May, Cyanophyta (22-65%) in September, and Cyanophycean (10-65%), Chlorophycean (10-60%), and Bacyllariophycean (5-80%) species in March. The zooplankton were dominated by cladoceran species (40-70%). Organochlorine and organophosphate insecticides were bioconcentrated (2- to 10-fold) from water to algae, 10- to 25-fold in zooplankton, and 8- to 140-fold in fish. GGTP activity and lipid peroxidation increased and AchE activity in fish decreased in response to the environmental stress caused by the elevated biomagnification of pesticides. The bioaccumulation of these contaminants in fish and the potential for biomagnification in humans are perceived as threats.