Cadmium In Tissues Research Articles

Some Elements in Thyroid Tissue are Associated with More Advanced Stage of Thyroid Cancer in Korean Women.

Excessive exposure to heavy metals including cadmium and lead is known to have adverse effects on various types of cancer. The aim of the present study was to evaluate the associations between blood and tissue levels of heavy metals and trace elements and different stages of thyroid cancer in Korean women. Ninety-two Korean women undergoing thyroidectomy were included in this study. Blood and thyroid tissue levels of cadmium, lead, mercury, selenium, and zinc were measured, and histopathological results, cancer tumor node metastasis (TNM) stage, and cancer multifocality were assessed. The tissue levels of cadmium, selenium, and zinc were significantly higher in patients with TNM stages 3 and 4 compared to those in stage 1. The tissue level of cadmium was greater in patients with higher tumor stage (≥T2) than those with lower stage (T1). Also, the tissue levels of cadmium and zinc were higher in multifocal group than in unifocal group. A logistic multiple regression analysis showed that the odds ratio (OR) for advanced tumor stage group (≥T2) increased in those with higher tissue cadmium level after adjustment (OR = 1.397, 95 % CI = 1.078-1.811). The accumulation of cadmium in thyroid tissue may be one of important etiologic factors for the thyroid cancer progression and aggravation in Korean women.

Heavy metals in yellowfin tuna (Thunnus albacares) and common dolphinfish (Coryphaena hippurus) landed on the Ecuadorian coast

Heavy metals are contaminants of great environmental concern due to their multiple origins (natural and anthropogenic), the ability to accumulate in organs and tissues, and the deleterious effects they can cause in organisms. Studies on the accumulation of metals in seafood, such as fish, have increased in importance due to the risk for human health when consuming fish contaminated by metals. The present work was aimed at verifying the concentrations of cadmium (Cd), mercury (Hg) and lead (Pb) in the muscular tissue and liver of yellowfin tuna (Thunnus albacares) and common dolphinfish (Coryphaena hippurus) from the Eastern Pacific Ocean landed in Manta city, Ecuador. Samples were analyzed by inductively coupled plasma mass spectroscopy (ICP-MS). Around half of the muscle samples of both species presented levels of Cd and Hg above the limits considered safe for human consumption established by the European Union. For Pb, most of the muscle samples were considered acceptable for consumption. Results indicate that both species should be consumed with some caution. Considering the tolerable weekly intake recommended for adults by the World Health Organization, results indicate that Hg is the main metal that limits the consumption of yellowfin tuna and common dolphinfish, with a recommended maximum ingestion, respectively, of 191 and 178g per week for an adult.

Metal uptake of tomato and alfalfa plants as affected by water source, salinity, and Cd and Zn levels under greenhouse conditions.

Irrigation with wastewater is a promising option to improve crop yields and to reduce pressure on freshwater sources. However, heavy metal concentrations in wastewater may cause health concerns. A greenhouse pot experiment was conducted in order to determine cadmium (Cd) and zinc (Zn) concentrations in sandy soil and plant tissues of tomato (Lycopersicon esculentum L.) and alfalfa (Medicago sativa L.). A 2 × 2 × 4 × 2 factorial treatment arrangement was utilized. Two water sources, fresh (FW) or treated wastewater (TWW), at two salinity levels (1 and 3 dS m(-1)) containing different levels of Cd and Zn were used. Samples were collected after a 90-day growth period. It was observed that the growth of both plants was depressed at the highest metal level (L3). Metal accumulation in plant parts increased with the increase of metal concentration and salinity in irrigation water. At low salinity, water source was the main factor which controlled metal accumulation, whereas, at high salinity, chloride appeared to be the principal factor controlling metal uptake regardless of water source. Metal translocation from roots to shoots increased in TWW-irrigated plants, even in the controls. Tomatoes accumulated Cd up to and above critical levels safe for human consumption, even though Cd concentration in irrigation water did not exceed the current recommended values. Therefore, food production in sandy soils may well pose a health hazard when irrigated with TWW containing heavy metals. Complexation with dissolved organic compounds (DOC) in TWW may be to be the principal factor responsible for increased metal uptake and transfer at low salinity, thereby increasing the risk of heavy metal contamination of food and forage crops.

Concentration of cadmium in cacao beans and its relationship with soil cadmium in southern Ecuador

Cadmium (Cd) content in cacao beans above a critical level (0.6mgkg−1) has raised concerns in the consumption of cacao-based chocolate. Little is available regarding Cd concentration in soil and cacao in Ecuador. The aim of this study was to determine the status of Cd in both, soils and cacao plants, in southern Ecuador. Soil samples were collected from 19 farms at 0–5, 5–15, 15–30, and 30–50cm depths, whereas plant samples were taken from four nearby trees. Total recoverable and extractable Cd were measured at the different soil depths. Total recoverable Cd ranged from 0.88 to 2.45 and 0.06 to 2.59, averaged 1.54 and 0.85mgkg−1, respectively in the surface and subsurface soils whereas the corresponding values for M3-extractable Cd were 0.08 to 1.27 and 0.02 to 0.33 with mean values of 0.40 and 0.10mgkg−1. Surface soil in all sampling sites had total recoverable Cd above the USEPA critical level for agricultural soils (0.43mgkg−1), indicating that Cd pollution occurs. Since both total recoverable and M3-extractable Cd significantly decreased depth wise, anthropogenic activities are more likely the source of contamination. Cadmium in cacao tissues decreased in the order of beans>shell>>leaves. Cadmium content in cacao beans ranged from 0.02 to 3.00, averaged 0.94mgkg−1, and 12 out of 19 sites had bean Cd content above the critical level. Bean Cd concentration was highly correlated with M3- or HCl-extractable Cd at both the 0–5 and 5–15cm depths (r=0.80 and 0.82 for M3, and r=0.78 and 0.82 for HCl; P<0.01). These results indicate that accumulation of Cd in surface layers results in excessive Cd in cacao beans and M3- or HCl-extractable Cd are suitable methods for predicting available Cd in the studied soils.

The suitability of Trapa natans for phytoremediation of inorganic contaminants from the aquatic ecosystems

Abstract The discharges from industries contaminate ponds maintained by the villagers for various purposes including cultivation of Trapa natans (L.) which bears fruits during winter season. The fruits of T. natans are edible and sold in local markets on the large scale. In the present study, the plants of T. natans were collected from ten ponds located nearby industrial areas of Unnao District, U.P., India to assess cadmium (Cd) and copper (Cu) accumulation in different tissues including the fruits. It was found that Cd in water ranged from 0.006 mg L−1 (Sareni) to 0.015 mg L−1 (Maurawa and Ajgain). The highest concentration of Cu was found in Bara region (0.226 mg L−1), whereas, it was lowest in Nigoha (0.008 mg L−1). Both the metals were accumulated in significant amount in the roots, shoots and fruits of T. natans. Cadmium was accumulated highest in the roots, shoots and fruits i.e. 2.656, 2.081 and 1.189 μg g−1 dry weights respectively of the plants, collected from Ajgain region. The highest concentration of Cu was found in the plant tissues of Bara region i.e. 15.626, 12.3, 9.46 μg g−1 dry weights in roots, shoots and fruits respectively. It appeared that substantial amount of the metals was found to be accumulated in the roots and shoots, which depicts the metal accumulating ability of this plant. However, both Cd and Cu were translocated in the fruits of T. natans which are edible, and thus showed a risk to contaminate the food chain and may also become hazardous for the human health if the same plants are used for the consumption purposes. The results of this study indicate that T. natans is a suitable candidate for the phytoremediation of heavy metals from the aquatic ecosystem but the process requires a proper care and maintenance.

Physiological effects and reduced tolerance following maternal metal exposure in the live‐bearing fish Gambusia affinis

The present study assessed the effects of maternal copper or cadmium exposure in a live-bearing fish. After a 10-d exposure to background levels (control) or 0.15 μM copper or cadmium, gravid females were transferred to clean water. Once a female gave birth, the authors analyzed her newborn offspring for lipid peroxidation, elemental composition (copper, cadmium, and calcium), and metal tolerance. The authors raised other offspring until sexual maturity and analyzed their growth rate, incidence of abnormalities, and sex ratio. Their earlier research, using the same species and exposure design, demonstrated that cadmium and copper were transferred from gravid females to their offspring. The present study showed that offspring of copper-exposed females had a reduced size at birth, developmental abnormalities, elevated tissue cadmium levels, and reduced tissue calcium levels. Offspring of cadmium-exposed females had elevated levels of lipid peroxidation, developmental abnormalities, and lower tissue levels of both copper and calcium. No effects were detected with respect to offsprings' growth rate or sex ratio. Offspring of metal-exposed fish had a reduced tolerance to the metal that their female parent had been exposed to, and the tolerance showed an inverse relationship to the tissue metal level in the offspring. The latter indicates that the reduced tolerance was the result of an increased body burden prior to the tolerance quantification. The present study constitutes the first report in live-bearing fishes showing that maternal metal exposure has a wide range of negative impacts on the offspring.

Distribution and age-related bioaccumulation of lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As) in tissues of common carp (Cyprinus carpio) and European catfish (Sylurus glanis) from the Buško Blato reservoir (Bosnia and Herzegovina)

The purpose of this study was to quantify the bioaccumulation of Pb, Hg, Cd, and As in tissues of carp (Cyprinus carpio) and catfish (Silurus glanis) from Buško Blato in Bosnia and Herzegovina. Arsenic concentrations were below the Maximal Admissible Concentration (MAC) for Croatia and other countries. Mercury concentrations were below 1mgkg−1, but in most muscle samples of both species and all catfish liver samples, the values were higher than 0.5mgkg−1 (higher than the MAC for many countries including Croatia). Lead concentrations were higher than 1mgkg−1 (the MAC for Croatia) in most muscle samples; all kidney and most catfish liver samples also exceeded 1mgkg−1. Cadmium concentrations in all tissues, other than the gonads, were higher than 0.1mgkg−1 (MAC for Croatia), with the highest concentrations found in the kidneys. The only gender difference was found in carp, where a 68.4% higher concentration of As was found in the fry compared to the milt (P<0.05). Concentrations of all of the elements were higher in catfish compared to carp for most tissues. Significant correlations were found between all of the elements in the muscles and the liver of carp. In catfish, the muscles were the only tissue in which multiple correlations were found. Linear positive correlations with age and body mass were demonstrated for the concentrations of all heavy metals for all tissues except the gonads in both fish species. We concluded that significant heavy metal accumulation in carp and a catfish tissues correlates with age and body mass; bioaccumulation is species- and tissue-specific and is different for each element.

Fitodisponibilidade de metais e produção de tifton 85 cultivada com diferentes fontes e doses de zinco

The element zinc (Zn) is considered an essential micronutrient to plants, being that the addition of this metal in forage cultivation may cause increment in the productivity. In Brazilian soils are frequent the cases of Zn deficiency, being necessary the fertilization of these areas with this micronutrient. However it must be highlighted that some sources of this micronutrient available in the market present in its composition heavy metals. This work aimed to study the effect of different sources and doses of Zn applied in Tifton 85 and the production of dry matter and the levels of Zn, phosphorus (P), cadmium (Cd), lead (Pb) and chromium (Cr) in leaf tissue and the levels Zn, Cd, Pb and Cr in soil. The experiment was conducted in a greenhouse using a Rhodic oxisol of medium texture. Vases with volume of 4 dm 3 were used, which were organized in a completely randomized in factorial scheme (5x4) with three replications. The treatments were the five sources of Zn (A, B, C, D) in four doses of the micronutrient (0, 2, 4, 6 kg ha -1 ). The results show that did not occurred accumulation of Cd, Pb and Cr in the leaf tissue and Cd and Cr in the soil. The source E provided higher production of dry matter in relation to the sources A, B, C, D. However the source 'A' provided higher concentrations of Zn for the forage.

Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: implication of organic acids in these processes.

The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic, and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 μM Cd, 100 μM Ni and the combination of 50 μM Cd + 100 μM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected plant development. Cadmium and Ni concentrations in tissues and xylem sap were higher in plants subjected to individual metal application than those subjected to the combined effect of Cd and Ni suggesting a possible competition between these metals for absorption. Both metals applied separately or in combination induced an increase in citrate concentration in shoots and xylem sap but a decrease of this concentration in the roots. However, a minor relationship was observed between metal application and fumaric, malic, and ascorbic acids. Both observations suggest the implication of citric acid in Cd, Ni translocation and shoot accumulation in S. portulacastrum. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could be involved in metal chelation and thus contributes to heavy metal tolerance in this species.

Acute Cadmium Exposure Reduces the Local Angiotensin I Converting Enzyme Activity and Increases the Tissue Metal Content.

Cadmium exposure causes health problems that may result from increased oxidative stress and from changes in enzyme metalloproteases activities as angiotensin-converting enzyme (ACE). In fact, cadmium produces inhibition of serum ACE but is not known how cadmium acts on tissue ACE activity and whether following acute exposure tissue cadmium content is increased. In order to elucidate these issues, a cadmium bolus was injected intravenously in Wistar rats, and the cadmium content and the ACE activity were measured in the serum, lungs, aorta and kidneys. Moreover, in order to clarify if the cadmium affects directly tissue ACE activity, acute metal exposure in vitro was performed. Our results demonstrated that 120min following cadmium administration, blood and organ cadmium content were both increased. Serum and lung ACE activity were reduced following acute cadmium exposure, but aortic and kidney ACE activities were not affected. The inhibitory effects induced by cadmium on ACE activity were also observed in the serum, as well as the lungs and the aorta, but not in the kidneys following in vitro exposure. Moreover, the inhibitory effects induced by cadmium on ACE activity were partially restored in vitro by zinc supplementation, suggesting a possible interaction or competition between cadmium and zinc by at the active site of ACE. Summarising, our results suggest that acute cadmium exposure promotes an increase in the tissue metal content that was accompanied by direct inhibition of serum, aorta and lung ACE activity, an effect that is cadmium concentration-dependent and is partially reversed by zinc.

Determination of toxic heavy metal levels in commonly consumed species of shrimp and shellfish using ICP-MS/OES

Toxic metal concentrations, including lead (Pb), cadmium (Cd), aluminum (Al), mercury (Hg), and arsenic (As) in edible tissues of different species of shrimp and shellfish consumed in South Korea were analyzed. Analysis was performed using inductively coupled plasma (ICP)-MS) for Pb, Cd and As, ICP-optical emission spectrometry (OES) for Al, and a direct mercury analyzer for Hg. Methods used were validated. Limited variation in heavy metal concentrations between shrimp and shellfish were observed. Al and As concentrations were highest while Hg was lowest. Heavy metal levels found in edible tissues of shellfish and shrimp were below international and local maximum permissible levels for human consumption. The methods used were accurate and reproducible for use in determination of toxic heavy metal levels in seafoods.

Metal Transfer from Marine Coastal Sediment to Food Chain: Evaluating Strombus (Conomurex) persicus for Monitoring Metal Bioaccumulation

Protection of the ecosystems ultimately contributes towards their sustainability. Presence of high levels of toxic metals in seafood is considered as an environmental warning for possible influences on the ecosystem components and public health. This research quantified the concentrations of cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), lead (Pb), vanadium (V), and zinc (Zn) in sediments and edible soft tissue of shellfish Strombus(Conomurex)persicus from the Sea of Oman. In both matrices, metals exhibited no general trend in the distribution of metals between the sampling sites. In shellfish, metal levels were below the international maximum permissible guidelines, illustrating safe consumption of this seafood item. The calculated risk factor (Eri) for Cr, Cu, Pb, and Zn revealed no ecological damage should be anticipated at the reported metal concentrations in the sediment samples. However, Cd had higher Eri range, suggesting moderate to considerable ecological risk. For transfer of metals from sediment toS. persicus, bioaccumulation factors (BAF) estimated for Cd, Cu, and Zn were above 1.0, indicating tendency of these metals to accumulate in S. persicus. While the BAF and Eri values for Zn were insignificantly correlated, BAF values for Cd and Cu were inversely related to their corresponding Eri values. Nevertheless, correlation was not statistically significant for Cu. For Cd, it seems that sediments having higher Eri may not be necessarily resulting in higher tissue Cd burdens of S. persicus. In conclusion, it appears that the use of correlation between BAF andErito examine transfer of metals from abiotic component to organisms in natural waters is limited.

Heavy Metals in Some Fish Species and Bivalves from the Mediterranean Coast of Egypt

Biota samples were collected seasonally during three consecutive years from the Egyptian costal region along the Mediterranean Sea for analysis of Zn, Cu, Cd, Pb and Hg. In addition to bivalve Donax, seven commercially important species of fish were examined to provide a comprehensive assessment for the concentrations of these metals in the Mediterranean coastal region of Egypt. Despite of the presence of several land-based sources of contamination, particularly at El-Mex Bay and El-Maadiya, the results showed very weak increase in the concentration of copper, lead and mercury revealing no accumulation of these metals in the biological material, even in non-migrant bivalve species such as Donax. However, an increase in the concentration of zinc and cadmium in fish tissues was measured from 1993 to 1995. Regardless of the fish species, no significant differences were observed in concentrations of most metals between different locations and from season to season. Regarding concentrations of most metals, no interspecies differences could be also measured in either fish tissues or in bivalve Donax. The study indicated that the concentration of these heavy metals were well below the documented toxic levels for human consumption and represent baseline levels against which possible future heavy-metal contamination can be measured.

Analysis of the content of cadmium and zinc in parts of the human hip joint.

Cadmium is an element with proven direct and indirect toxic effects on bones. Zinc affects the content of cadmium in the human body. These elements show antagonistic interactions. The aim of the research was to determine the levels of cadmium and zinc in the hip joint tissues and interactions between these elements. The study group consisted of 91 subjects, 66 women and 25 men. The tissues were obtained intraoperatively during hip endoprosthetic surgery. The levels of cadmium and zinc were assayed by the atomic absorption spectrophotometry (AAS) method. The analysis of the content of cadmium and zinc in different parts of the hip joint, i.e., articular cartilage, cortical bone, and cancellous bone of the femoral head as well as the articular capsule and a fragment of the cancellous bone taken from the intertrochanteric region of the femoral bone showed significant differences. The cancellous bone was found to have the highest potential to accumulate the elements studied, whereas part of the articular capsule the lowest. Higher levels of cadmium and zinc were observed in samples obtained from men. Patients with bone fractures had higher cadmium content than those with osteoarthritis. The study on the content of cadmium and zinc in the tissues of the hip joint is one of the primary research biomonitoring.

Accumulation of Arsenic and Cadmium in Foods of Animal Origin Collected from the Local Markets in Northeastern Region Thailand

Concentrations of arsenic and cadmium were determined in broiler chickens, cattle and swine collected from the local markets of the northeastern Thailand. Average concentrations of arsenic based on a wet weight basis in muscle, liver and kidney were 0.022±0.008, 0.068±0.025, 0.286±0.073 μg/g cattle; 0.045±0.022, 0.402±0.096, 0.812±0.335 μg/g chickens; and 0.116±0.044, 0.479±0.142, 1.012±0.500 μg/g swine, respectively. Cadmium levels in meat of cattle, chickens and swine samples were 0.024±0.010, 0.028±0.006 and 0.042±0.015 μg/g, respectively. In liver and kidney, average of cadmium levels was 0.286±0.062 and 0.412±0.074 μg/g cattle; 0.312±0.092 and 0.645±0.068 μg/g chickens and 0.368±0.106 and 0.758±0.120 μg/g swine, respectively. Statistical analysis showed that chickens and swine levels were higher of these elements than in cattle. None of samples, however, exceeded the arsenic limits set by Thailand regulations and the average concentrations of cadmium in animal tissues were still within acceptable levels of Thailand standards.

Application of ICP OES to determination of cadmium, selenium and chromium in tissues in postmortem material

Application of ICP OES to determination of cadmium, selenium and chromium in tissues in postmortem material

Distribution of Zinc and Cadmium in Tissues of Giant Reed (Arundo Donax L.): Sequential Extraction - Radiometric Study

Abstract Heavy metals are taken up by the vascular plant root system from water solutions in cationic forms. Subsequently, during both short and long distance transport to other plant tissues, cation forms are incorporated to many bioorganic compounds differing in stability, ionic character and physico-chemical properties such as solubility in lipid structures and mobility across cell membrane systems. Many sequential and single step extraction methods have been elaborated for characterization of the role of individual components of plant cells components in transport and detoxication of heavy metals. In our study, dry biomass of giant reed (Arundo donax L.) grown in hydroponic media spiked with 65ZnCl2 and 109CdCl2 was treated with dithizone solutions as complexing ligand in order to convert free Zn2+ and Cd2+ ions to corresponding dithizonates. Treatment with dithizone showed that up to 67 % of the total plant Cd and 56 % of the total plant Zn were transformed to dithizonate complexes extracted with chloroform. Extraction of biomass with Folch reagent showed that up to 48 % of the total root cadmium and up to 18 % of the total shoot cadmium is bound in lipid fraction. Zinc was not found in lipid fraction of root and shoot. Derivatization of the dried root and shoot lipid fraction by dithizone showed that two third of Cd in root and practically all Cd in shoot lipid fraction could be transformed to Cd-dithizonate. Methods of biomass treating with complexing ligands and a method of sequential extraction procedures with non-polar organic solvents and radiotracer methodology seem to be useful methods for the study of metal speciation and distribution in vascular plants

Exposure–dose–response relationships of the freshwater bivalve Hyridella australis to cadmium spiked sediments

To understand how benthic biota may respond to the additive or antagonistic effects of metal mixtures in the environment it is first necessary to examine their responses to the individual metals. In this context, laboratory controlled single metal-spiked sediment toxicity tests are useful to assess this. The exposure–dose–response relationships of Hyridella australis to cadmium-spiked sediments were, therefore, investigated in laboratory microcosms. H. australis was exposed to individual cadmium spiked sediments (<0.05 (control), 4±0.3 (low) and 15±1 (high) μg/g dry mass) for 28 days. Dose was measured as cadmium accumulation in whole soft body and individual tissues at weekly intervals over the exposure period. Dose was further examined as sub-cellular localisation of cadmium in hepatopancreas tissues. The biological responses in terms of enzymatic and cellular biomarkers were measured in hepatopancreas tissues at day 28. H. australis accumulated cadmium from spiked sediments with an 8-fold (low exposure organisms) and 16-fold (high exposure organisms) increase at day 28 compared to control organisms. The accumulated tissue cadmium concentrations reflected the sediment cadmium exposure at day 28. Cadmium accumulation in high exposure organisms was inversely related to the tissue calcium concentrations. Gills of H. australis showed significantly higher cadmium accumulation than the other tissues. Accumulated cadmium in biologically active and biologically detoxified metal pools was not significantly different in cadmium exposed organisms, which suggests that H. australis has some tolerance to cadmium. The metallothionein like protein fraction played an important role in the sequestration and detoxification of cadmium and the amount sequestered in this fraction increased with increased cadmium exposure. The highest percentage of biologically active cadmium was associated with the lysosome+microsome and mitochondrial fractions. Cadmium concentrations in these two fractions of cadmium exposed organisms were significantly higher with respect to controls. Total antioxidant capacity decreased with increased cadmium exposure and tissue dose. Lipid peroxidation increased and lysosomal membrane stability decreased significantly with increased cadmium exposure and tissue dose. Based on exposure–dose–response analysis in this study, H. australis would be a suitable organism for assessing cadmium sediment exposure and toxicity.

Comparing trace metal bioaccumulation characteristics of three freshwater decapods of the genus Macrobrachium

Potential sources and kinetics of metal bioaccumulation by the three Macrobrachium prawn species M. australiense, M. rosenbergii and M. latidactylus were assessed in laboratory experiments. The prawns were exposed to two scenarios: cadmium in water only; and exposure to metal-rich mine tailings in the same water. The cadmium accumulation from the dissolved exposure during 7 days, followed by depuration in cadmium-free water for 7 days, was compared with predictions from a biokinetic model that had previously been developed for M. australiense. M. australiense and M. latidactylus accumulated significant tissue cadmium during the exposure phase, albeit with different uptake rates. All three species retained >95% of the bioaccumulated cadmium during the depuration phase, indicating very slow efflux rates. Following exposure to tailings, there were significant (p<0.05) differences in tissue arsenic, cadmium, lead and zinc concentrations among species. Cadmium and zinc concentrations were increased relative to controls for all three species but were not different between treatments (direct/indirect contact with tailings), suggesting these metals were primarily accumulated via the dissolved phase. All species bioaccumulated significantly greater arsenic and lead when in direct contact with mine tailings, demonstrating the importance of an ingestion pathway for these metals. Copper was not bioaccumulated above control concentrations for any species. The differences between the metal accumulation of the three prawns indicated that a biokinetic model of cadmium bioaccumulation for M. australiense could potentially be used to describe the metal bioaccumulation of the other two prawn species, albeit with an over-prediction of 3–9 times. Despite these being the same genus of decapod crustacean, the study highlights the issues with using surrogate species, even under controlled laboratory conditions. It is recommended that future studies using surrogate species quantify the metal bioaccumulation characteristics of each species in order to account for any differences between species.

Heavy metals in fish from the Aleutians: Interspecific and locational differences

The objectives of this study were to examine levels of arsenic, cadmium, lead, mercury and selenium in edible tissue of seven species of marine fish collected from several Aleutian islands (in 2004) to determine: (1) interspecific differences, (2) locational differences (among Aleutian Islands), (3) size-related differences in any metal levels within a species, and (4) potential risk to the fish or to predators on the fish, including humans. We also compared metals levels to those of three other fish species previously examined in detail, as well as examining metals in the edible tissue of octopus (Octopus dofleini). Octopus did not have the highest levels of any metal. There were significant interspecific differences in all metal levels among the fish species, although the differences were less than an order of magnitude, except for arsenic (mean of 19,500ppb in Flathead sole, Hippoglossoides elassodon). Significant intraisland variation occurred among the four sites on Amchitka, but there was not a consistent pattern. There were significant interisland differences for some metals and species. Mercury levels increased significantly with size for several species; lead increased significantly for only one fish species; and cadmium and selenium decreased significantly with size for halibut (Hippoglossus stenolepis). The Alaskan Department of Health and Social Services supports unrestricted consumption of most Alaskan fish species for all people, including pregnant women. Most mean metal concentrations were well below the levels known to adversely affect the fish themselves, or predators that consume them (including humans), except for mercury in three fish species (mean levels just below 0.3ppm), and arsenic in two fish species. However, even at low mercury levels, people who consume fish almost daily will exceed guideline values from the Centers for Disease Control and the Environmental Protection Agency.