DNA barcodes reveal species-specific mercury levels in tuna sushi that pose a health risk to consumers

Excessive ingestion of mercury—a health hazard associated with consuming predatory fishes—damages neurological, sensory-motor and cardiovascular functioning. The mercury levels found in Bigeye Tuna (Thunnus obesus) and bluefin tuna species (Thunnus maccoyii, Thunnus orientalis, and Thunnus thynnus), exceed or approach levels permissible by Canada, the European Union, Japan, the US, and the World Health Organization. We used DNA barcodes to identify tuna sushi samples analysed for mercury and demonstrate that the ability to identify cryptic samples in the market place allows regulatory agencies to more accurately measure the risk faced by fish consumers and enact policies that better safeguard their health

Metal concentrations (AS, CD, CR, PB, HG and SE) in Dolly Varden (Salvelinus malma) from the Aleutian Islands, Alaska:

Concerns about contaminants in fish have increased in recent years, especially in species consumed heavily in subsistence diets. Most studies of contaminants in Alaskan subsistence foods have focused on mainland Alaska not the Aleutian Islands. Several islands along the Aleutian Archipelago of Alaska have supported military bases which may be a source of pollution, and the proximity of the Aleutian chain to Eastern Asia may increase its susceptibility to atmospheric deposition of heavy metals. This study compares levels of arsenic, cadmium, chromium, lead, mercury and selenium in the egg, kidney, liver and muscle of Dolly Varden (Salvelinus malma) from Umnak, Adak, and Amchitka Islands in the Aleutian Chain of Alaska. I examined levels as a function of tissue, gender, collection site, and size. There were significant differences in the levels of metals as a function of tissue, with kidney having the highest levels of arsenic and cadmium, and kidney and liver having significantly higher levels of chromium and mercury than the other tissues examined. Selenium and arsenic in muscle and liver were highly correlated with both length and weight of fish. Arsenic and mercury in muscle were highly correlated with levels in liver, kidney and egg. There were few significant gender differences in metal concentrations, with females having higher levels of chromium in muscle and cadmium in kidney than males. However selenium in liver was higher in males than females. On Amchitka mean mercury levels were higher in both muscle (149 ppb; ng/g, wet weight) and liver (321 ppb) compared to fish from Adak and Umnak (muscle = 24 ppb and liver = 44 ppb). Dolly Varden collected from Cannikin Lake and Fox Lake on Amchitka were probably not sea run. This may explain the elevated mercury levels found in Dolly Varden from Amchitka Island. Landlocked Dolly Varden feed more heavily on smaller fish and fish eggs which places them at a higher trophic level than anadromous fish which primarily feed on amphipods. Selenium levels were highest in muscle (761 ppb) and liver (1,860 ppb) of fish caught in Cannikin Lake on Amchitka Island. Overall, concentrations of the metal contaminants in Dolly Varden were relatively low when compared with other studies on anadromous and marine fish from the region, and differences among collection sites may be due to trophic level differences between landlocked (Cannikin Lake) and sea-run Dolly Varden.M.S.Includes bibliographical references (p. 56-76)by Christian Jeitne

Mercury, Lead, Cadmium, Cobalt, Arsenic and Selenium in the Blood of Semipalmated Sandpipers (Calidris pusilla) from Suriname, South America: Age-related Differences in Wintering Site and Comparisons with a Stopover Site in New Jersey, USA

It is essential to understand contaminant exposure and to compare levels of contaminants in organisms at different ages to determine if there is bioaccumulation, and to compare levels encountered in different geographical areas. In this paper, we report levels of mercury, lead, cadmium, cobalt, arsenic and selenium in the blood of semipalmated sandpipers (Calidris pusilla) wintering in Suriname as a function of age, and compare them to blood levels in northbound migrants at a stopover in Delaware Bay, New Jersey. We found (1) young birds had higher levels of cadmium, cobalt, and lead than adults (after second year birds); (2) there were no age-related differences for arsenic, mercury and selenium; (3) only four of the possible 16 inter-metal correlations were significant, at the 0.05 level; (4) the highest correlation was between cadmium and lead (Kendall tau = 0.37); and (5) the adult sandpipers had significantly higher levels of cadmium, mercury and selenium in Suriname than in New Jersey, while the New Jersey birds had significantly higher levels of arsenic. Suriname samples were obtained in April, after both age classes had spent the winter in Suriname, which suggests that sandpipers are accumulating higher levels of trace elements in Suriname than in Delaware Bay. The levels of selenium may be within a range of concern for adverse effects, but little is known about adverse effect levels of trace elements in the blood of wild birds

Assessment of non-invasive techniques for monitoring mercury concentrations in species of Amazon turtles

This study determined the concentrations of mercury (Hg) in four tissues of six species of turtles from the Rio Negro in the Amazon Basin. For two species, blood and carapace tissues were correlated with concentrations in internal tissues to establish whether blood or carapace could serve as a non-lethal indicator of internal metal exposure or body burden. The four tissues' Hg levels were also correlated to turtle size and gender. The liver in five species of turtles had the highest concentration, followed by carapace, muscle, and blood. The exception was Chelus fimbriatus, which had a higher metal concentration in the muscle than carapace. Regarding the correlation between total Hg concentrations in tissues of the two species, no significant correlation was noted for Podocnemis erythroce-phala. However, for Podocnemis sextuberculata significant correlation was found between muscle × liver, muscle × blood, and liver × blood. For P. erythrocephala, there was a correlation between Hg concentration in carapace and turtle size. For P. sextuberculata, there was no marked correlation between Hg concentration and size, but concentration in muscle was significantly influenced by gender. The patterns of Hg accumulation in tissues of the five species followed those described for freshwater species and some species of sea turtles. The difference in C fimbriatus may be a result of a different pattern of non-living keratin layers on the carapace tissue. The use of carapace to infer internal concentrations of Hg is common in freshwater and sea turtles, but in this study it was found that only blood might be a reliable indicator of Hg concentrations in liver and muscle tissues for P. sextuberculata. Thus blood may be used as a non-invasive method to study concentrations of Hg in liver and muscle of P. sextuberculata.© 2011 Taylor& Francis

Arsenic, cadmium, chromium, lead, mercury, and selenium levels in blood of four species of turtles from the Amazon in brazil

Using blood as a method of assessing metal levels in turtles may be useful for populations that are threatened or endangered or are decreasing. In this study the levels of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in blood of four species of turtles from the tributaries of the Rio Negro in the Amazon of Brazil were examined. The turtles included the six-tubercled Amazon (river) turtle (Podocnemis sextuberculata), red-headed Amazon (river) turtle (Podocnemis erythrocephala), big-headed Amazon (river) turtle (Peltocephalus dumerilianus), and matamata turtle (Chelus fimbriatus). Blood samples were taken from the vein in the left hind leg of each turtle. There were significant interspecific differences in the sizes of the turtles from the Rio Negro, and in concentrations of Pb, Hg, and Se; the smallest species (red-headed turtles) had the highest levels of Pb in their blood, while Se levels were highest in big-headed turtles and lowest in red-headed turtles. Hg in blood was highest in matamata, intermediate in big-headed, and lowest in the other two turtles. Even though females were significantly larger than males, there were no significant differences in metal levels as a function of gender, and the only relationship of metals to size was for Cd. Variations in metal levels among species suggest that blood may be a useful bioindicator. Metal levels were not high enough to pose a health risk to the turtles or to consumers, such as humans

Snake Fungal Disease in Free-Ranging Northern Pine Snakes (<i>Pituophis melanoleucus melanoleucus</i>) in New Jersey: Lesions, Severity of Sores and Investigator’s Perceptions

Ophidiomyces ophidiicola, the fungus causing snake fungal disease (SFD), has been identified in northern pine snakes (Pituophis melanoleucus) in New Jersey. In this paper, we (1) review the positivity rate of SFD on different locations on snakes’ bodies, (2) determine the relationship between the sores and quantitative polymerase chain reaction (qPCR) positivity rates, and (3) explore the relationship between the investigators’ clinical evaluation of the severity of sores, their evaluation of the likelihood of the sores being positive, and the qPCR positivity of SFD for the sores. Swabbing the sores was more effective at determining whether the snakes tested positive for O. ophidiicola than ventrum swabbing alone. The perception of the severity of the sores did not relate to qPCR positivity for O. ophidiicola. We suggest that the assessment of the rate of SFD among snakes in the wild needs to include the sampling of snakes with no clinical signs, as well as those with sores, and the swabbing of all the sores collectively. Clear terminology for sores, the identification of clinical signs of SFD, and distinguishing the rates of O. ophidiicola by PCR testing should be adopted. Overall, the pine snakes exhibited a higher rate of sores and positivity of O. ophidiicola swabs by PCR testing compared to the other snakes