Comparative bioavailability of trace metals using three filter-feeder organisms in a subtropical coastal environment (Southeast Gulf of California)

To evaluate the relative bioavailability of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in the coastal waters of one selected site in Mazatlán Harbor, different filter feeder organisms, an oyster (Crassostrea corteziensis), a mussel (Mytella strigata) and a barnacle (Fistulobalanus dentivarians), were sampled during 1 year. Seasonal and interspecific variations in some metal concentrations were evident, especially for Cd, Ni, Pb and Zn. In contrast with Fe, Pb and Zn, the concentrations of Cd varied accordingly in both bivalves. Even though the organisms live in the same site and have a common feeding mechanism, accumulated body Cd concentrations were different. Mussels concentrated significantly higher levels of Ni than the other organisms, while barnacles were better concentrators of Cd, Pb and Zn. A relationship existed between the concentrations of Cd, Fe and Zn in the soft tissues of the two bivalves, which is useful in monitoring studies when only one species occurs.     

Age and proximity to local ore-smelters as determinants of tissue metal levels in beaver (Castor canadensis) of the sudbury (Ontario) area

An examination of tissue metal levels in Sudbury-area beaver (Castor canadensis) revealed that animals in the vicinity of the local ore-smelters contained elevated burdens of Ni and Pb in the liver and kidneys. Tissue concentrations averaged 1.5- to 2.5-fold higher than background values and are believed to reflect accumulations resulting through food chain contamination. Tissue levels of Cu, Cd and Zn did not vary in relation to distance from source. Tissue Cd levels were uniformly elevated throughout the four populations examined and are believed to reflect an enhanced level of food chain transfer occurring on the poorly buffered, acid-sensitive soils of the area. Burden: body weight correlations indicated that tissue concentrations of Cd increased whereas Cu levels decreased as a function of animal age. Most striking among these age-related trends was the disproportionate uptake of Cd by renal tissues, resulting in 10-fold higher burdens than those present within the liver.     

Distribution and coassociations of selected metals in seals of the Antarctic

Zinc, Cu, Cd, Pb, Ag, Ni, Co, Cr, Fe and Mn concentrations in some tissues of crabeater seal (Lobodon carcinophagus), leopard seal (Hydrurga leptonyx) and Weddell seal (Leptonychotes weddelli) from the Antarctic were determined. Distinct inter-tissue differences in metal concentrations in seals were observed; liver contained maximum levels of Zn, Cu, Ag and Mn, whilst kidney showed the highest levels of Cd, Ni and Co. Muscle was characterized by low concentrations of all the elements analyzed. The metal concentrations in the vertebrates analyzed were compared with those for organisms originating from various aquatic areas. Significant correlations were found between the levels of several of the metals analyzed, e.g. between renal and hepatic concentrations of Zn and Cd. Strong relationships between the hepatic concentrations of some metals were found, e.g. Cd-Zn. These two metals also showed a significant coassociation in their renal concentrations. The slope of the regression line for renal Cd/Zn was about three times higher than the hepatic one and this may reflect a relatively high Cd exposure, probably from specific food (squid and krill) provenance, of the seals analyzed.     

Levels of lead, cadmium and other elements in mink and otter from Ontario, Canada

Concentrations of Pb, Cd, Cu, Ni, Fe, Zn, Mn, Ca, P, Mg and S were measured in tissues of mink (Mustela vision) and river otter (Lutra canadensis) from five areas of Ontario, Canada. Bone Pb levels in both species were lowest in animals from the collection site most remote from industrial activity and atmospheric deposition of pollutants. Mean liver and kidney Cd levels were also different between collection sites and may reflect natural and/or anthropogenic sources. Copper levels in liver, but not kidney, were elevated in mink and otter from the heavily Cu-contaminated Sudbury region. However, tissue levels did not reflect environmental loading of other metals, such as Fe, Ni and Zn, in the Sudbury area. This may be a function of effective homeostatic regulation in mammals, or low potential for biomagnification of these elements.     

Residual metal concentrations in soils and leaf accumulations in tobacco a decade following farmland application of municipal sludge

The objectives of this investigation were to examine the long-term residual effects of metal loading through sewage sludge applications on the total vs. diethylene triamine pentacetic acid (DTPA) extractable metal concentrations in soil and leaf accumulations in tobacco. Maryland tobacco (Nicotiana tabacum L.), cv. 'MD 609', was grown in 1983 and 1984 at two sites in Maryland that had been amended in 1972 with dewatered, digested sewage sludge from washington, DC, at rates equal to 0, 56, 112 and 224 mg ha(-1). The metal concentrations in the sludge, in mg kg(-1) dry weight, were: 1300 Zn, 570 Cu, 280 Pb, 45 Ni and 13 Cd. Soil samples collected from the surface horizon and composite leaf samples of cured tobacco were analyzed for total Zn, Cu, Mn, Fe, Pb, Ni and Cd concentrations. The soil samples were also examined for soil pH and DTPA extractable metals. Equations were generated using polynomic and stepwise regression analyses which described the relationships between total vs. DTPA extractable soil metals, and between DTPA soil and soil pH vs. plant metal concentrations, respectively. Significant increases were observed for both total and DTPA extractable metal concentrations for all metals, with all but total Mn and Ni being significant for linear and quadratic effects regarding sludge rates. However, linear relationships were found between DTPA extractable vs. total soil concentrations for all elements except Pb and Ni which were quadratic. Significant increases in plant Zn, Cu, Mn, Ni and Cd and decreases in Fe were observed with increased sludge rates. Plant Pb levels were unaffected by sludge applied Pb. Linear relationships were observed between plant Zn and Cd and DTPA soil metal levels: however, Mn and Cu levels were described by quadratic and cubic relationship, respectively. Relationships between plant Fe and Pb and DTPA extractable concentrations were nonsignificant. Additional safeguards to protect crop contamination from heavy metals such as Cd were discussed.     

Concentrations,spatial distribution,and pollution assessment of heavy metals in surficial sediments from upstream of Yellow River,China

Surface sediments were collected from 122 sites in the upstream of the Yellow River, China. The concentration of Fe, Mn, Cu, Ni, Zn, Cr, Pb, and Cd in sediments was investigated to explore the spatial distribution based on statistics and interpolation method. The results suggested that the concentrations of heavy metals were lower than potential effect levels (PEL). The samples above threshold effect level (TEL) for Pb and Zn were less than 10%, while almost 50% of samples for Ni exceeded PEL. Pb and Zn in sediments performed little or no adverse effects on the aquatic ecosystems. Higher concentrations of all heavy metals occurred in Qinghai and Gansu sections; the concentrations of Cu, Ni, and Zn were significantly higher than the Inner Mongolia section. Lower concentration of Fe, Mn, Cu, Ni, and Zn appeared in Qinghai section; the concentrations of Fe, Mn, Cr, and Pb manifested relatively steady and similar distributions and approximately decreasing tendency along the upstream of Yellow River.

     

A comparison of Cu, Pb, As, Cd, Zn, Fe, Ni and Mn determined by acid extraction/ICP-OES and ex situ field portable X-ray fluorescence analyses

Total concentrations of Cu, Pb, As, Cd, Zn, Fe, Ni and Mn were determined for 81 soil samples using two types of field portable X-ray fluorescence (FPXRF) system; dual isotope and X-ray tube. FPXRF metal concentrations were statistically compared with analytical results from aqua regia extractions followed by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) analysis. The ability of each FPXRF instrument to produce analytical results comparable to the reference method was assessed by linear regression. A high degree of linearity was found for Fe and Pb with the X-ray tube instrument and for Fe, Cu, Pb, Zn, Cd and Mn with the dual source instrument. FPXRF analyser performance improved with increased analysis time for Cu, Mn and Pb, whilst Fe, Zn, Cd, Ni and As showed no significant improvement. Particle size did not influence FPXRF analyser performance. Both the dual isotope and the X-ray tube FPXRF instruments are effective tools for rapid, quantitative assessment of soil metal contamination and for monitoring the efficacy of remediation strategies.     

Distribution and coassociations of trace elements in soft tissue and byssus of Mytilus galloprovincialis relative to the surrounding seawater and suspended matter of the southern part of the Korean Peninsula

The concentrations of Cd, Co, Cu, Cr, Fe, Hg, Mn, Ni, Pb, Sn, Ti and Zn were analyzed by AAS, ICP MS and AFS in soft tissues and byssal threads of Mytilus galloprovincialis from Masan Bay and Ulsan Bay, Korea. Spatial variations in metal concentrations were found. The levels of Cd, Pb, Hg, Cu, Zn, Co and Mn were very high in the mussels from Ulsan Bay (Sts. U1, U2) and comparable with elevated concentrations of these elements in Mytilus sp. reported to date for other geographical areas. Seasonal differences in some metal concentrations were also observed. These variations may be caused by factors such as: a large difference in seawater temperature, food supply for the mussel population and/or freshwater runoff of particulate metal to the coastal water and weight changes brought about by gonadal development and the release of sexual products. Pb, Cu, Zn, Co, Ni, Fe and Mn were more enriched in byssal threads than in the soft tissues, hence the byssus seems to be more sensitive in reflecting the availabilities of trace metals in the ambient waters. Concentrations of trace metals varied with respect to the size of mussels and season, depending on many factors like sexual development, and seawater temperature, etc. The levels of some trace metals in seawater, especially in suspended matter were correlated significantly with those in soft tissues and byssal threads. There were spatial variations in metal concentrations in the soft tissue and byssus attributed to different sources of trace elements located near the sampling sites. There were significant relationships between concentrations of some metals (Cd, Cu, Pb, and Zn) in mussel soft tissues and byssal threads and suspended matter. This suggests that M. galloprovincialis can be used as a sensitive biomonitor for the availabilities of trace elements in the coastal waters off Korea.     

Influence of solution acidity and CaCl2 concentration on the removal of heavy metals from metal-contaminated rice soils

Soil washing is considered a useful technique for remediating metal-contaminated soils. This study examined the release edges of Cd, Zn, Ni, Cr, Cu or Pb in two contaminated rice soils from central Taiwan. The concentrations exceeding the trigger levels established by the regulatory agency of Taiwan were Cu, Zn, Ni and Cr for the Ho-Mei soil and Pb for the Nan-Tou soil. Successive extractions with HCl ranging from 0 to 0.2 M showed increased release of the heavy metals with declining pH, and the threshold pH value below which a sharp increase in the releases of the heavy metals was highest for Cd, Zn, and Ni (pH 4.6 to 4.9), intermediate for Pb and Cu (3.1 to 3.8) and lowest for Fe (2.1), Al (2.2) and Cr (1.7) for the soils. The low response slope of Ni and Cr particularly for the rice soils make soil washing with the acid up to the highest concentration used ineffective to reduce their concentrations to below trigger levels. Although soil washing with 0.1 M HCl was moderately effective in reducing Cu, Pb, Zn and Cd, which brought pH of the soils to 1.1+/-0.1 (S.D.), the concurrent release of large quantities of Fe and Al make this remediation technique undesirable for the rice soils containing high clay. Successive washings with 0.01 M HCl could be considered an alternative as the dissolution of Fe and Al was minimal, and between 46 to 64% of Cd, Zn, and Cu for the Ho-Mei soil and 45% of Pb in the Na-Tou soil were extracted after four successive extractions with this dilute acid solution. The efficacy of Cd extraction improved if CaCl2 was added to the acid solution. The correlation analysis revealed that Cr extracted was highly correlated (P < 0.001) with Fe extracted, whereas the Cu, Ni, Zn, Cd or Pb extracted was better correlated (P < 0.001) with Al than with Fe extracted. It is possible that the past seasonal soil flooding and drainage in the soils for rice production was conducive to incorporating Cr within the structure of Fe oxide, thereby making them extremely insoluble even in 0.2 M HCl solution. The formation of solid solution of Ni with Al oxide was also possible, making it far less extractable than Cd, Zn, Cu, or Pb with the acid concentrations used.     

Concentrations of some heavy metals in water, sediment and fish species from the Atatürk Dam Lake (Euphrates), Turkey

Concentrations of heavy metals (Cd, Co, Cu, Fe, Hg, Mn, Mo, Ni, Pb and Zn) were measured in the water, sediment and fish species (Acanthobrama marmid, Chalcalburnus mossulensis, Chondrostoma regium, Carasobarbus luteus, Capoetta trutta and Cyprinus carpio) from the Atatürk Dam Lake, Turkey. Among the heavy metals studied Cd, Co, Hg, Mo and Pb were not detected in water, sediments and fish samples, while Ni was undetectable levels in fish samples. Levels of Cu, Fe, Mn and Zn varied depending on different tissues. The results of this study indicated that a general absence of serious pollution in the dam lake is due to heavy metals, where as the concentrations of elements found could mainly be attributed to geological sources.     

Trace element accumulation in Baikal seal (Phoca sibirica) from the Lake Baikal

Trace element concentrations (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Co and Hg) were determined in 60 Baikal seals and in fishes collected from Lake Baikal in 1992. Low levels of Hg and Cd were found in Baikal seals in comparison with those of marine mammals and it was due to their low concentrations in dietary fish. These results suggest that pollution by Hg and Cd was low in Lake Baikal and these toxic elements were unlikely to be the causative factors for mass mortality of Baikal seal in 1987-1988. Significant correlation of Hg concentration between hair and internal tissues suggested the use of hair for Hg monitoring in pinnipeds. Among essential elements, higher Fe and lower Cu levels were specifically found in the liver of Baikal seal. The noticeable accumulation of essential elements might be related to the unique and specific environment of Lake Baikal.     

The determination of heavy metals (Al,Mn, Fe,Ni, Cu,Zn, Cd and Pb) in urban snow using an atomic absorption graphite furnace

The concentrations of eight metals (Al, Mn, Fe, Ni, Cu, Zn, Cd and Pb) in snow from the island of Montréal were determined in quantities of nanogram per gram using an atomic absorption graphite furnace. An overall precision of 10% was achieved for all elements. Enrichment factors calculated indicated that Ni, Cu, Zn, Cd and Pb are most probably anthropogenically derived.     

The intestinal parasite Pomphorhynchus laevis (Acanthocephala) from barbel as a bioindicator for metal pollution in the Danube River near Budapest, Hungary

Concentrations of As, Al, Ag, Ba, Bi, Cd, Co, Cr, Cu, Fe, Ga, Mg, Mn, Ni, Pb, Sb, Sn, Sr, Tl, V and Zn were analyzed by inductively coupled mass spectrometry (ICP-MS) in the intestinal helminth Pomphorhynchus laevis and its host Barbus barbus. The fish were caught in the Danube river downstream of the city of Budapest (Hungary). Ten out of twenty one elements analyzed were found at higher concentrations in the acanthocephalan than in different tissues (muscle, intestine, liver and kidney) of barbel. Considering the fish tissues, most of the elements were present at highest concentrations in liver, followed by kidney, intestine and muscle. Spearman correlation analyses indicate that there is competition for metals between the parasites and the host. The negative relationships between parasite number and metal levels in organs of the barbel support this hypothesis. The bioconcentration factors for Ag, As, Ba, Bi, Cu, Ga, Mn, Pb, Sr, Tl, and Zn showed that the parasites concentrated metals to a higher degree than the fish tissues. They accumulated the metals As, Cd, Cu, Fe, Ni, Pb, Sr and Zn even better than established bioindicators such as the mussel Dreissena polymorpha as revealed by data from the literature. The results presented here emphasize that acanthocephalans of fish are very useful as sentinels for metal pollution in aquatic ecosystems. Ratio of metal concentrations in the parasites and the host tissues provide additional information. Not including acanthocephalans in accumulation bioindication studies with fishes (as still customarily done) may lead to false results.     

Relationship between heavy metals concentrations in egret species,their environment and food chain differences from two Headworks of Pakistan

Concentration of ten metals (Cd, Cr, Co, Cu, Fe, Li, Mn, Ni, Pb and Zn) were analyzed in the egg contents, prey and soil samples of little egret (Egretta garzetta) and cattle egret (Bubulcus ibis) from two Headworks to determine habitat and species-specific differences; to assess the importance of prey and habitat contamination as an exposure source for heavy metals. Concentration of Cu, Mn, Cr and Pb in egg contents, Fe, Co, Cu, Mn, Zn in prey and Fe, Co, Cu, Ni, Li in surface soils were significantly different (P < 0.05). Mean metal concentrations of Cr, Pb and Cd were relatively higher in little egret whereas Cu and Mn were higher in the egg contents of cattle egret. The mean concentrations of Cu, Mn and Zn were higher in prey samples of cattle egrets and Cr, Cd and Pb in prey samples of little egrets. In soil samples collected from little egret heronries metal concentrations were higher except Cu and Ni. Correlation Analysis and Hierarchical Agglomerative Cluster Analysis (HACA) identified relatively similar associations of metals and their source identification. Metals such as Fe, Cu, Mn, and Li were related with geochemical origin from parent rock material as well as anthropogenic input whereas Cr, Cd, Pb, Ni, Co and Zn were associated mostly with anthropogenic activities. The study suggested that eggs are useful bio-monitor of local heavy metal contamination.     

Distribution and relationships of trace metals in soft tissue,byssus and shells of Mytilus edulis trossulus from the southern Baltic

Concentrations of Hg, Cd, Pb, Ag, Cu, Zn, Cr, Ni, Co, Mn, and Fe in soft tissues, shells and byssus of blue mussel (Mytilus edulis trossulus) from 23 sites along the Polish coast of the Baltic Sea were determined by AAS method. Byssus, as compared with the soft tissue, concentrated more effectively Pb, Cu, Cr, and especially Ag, Ni, Mn and Fe, moderately Hg and Zn and less effectively Cd. Significant inter-regional and inter-size differences in metal concentrations in both soft tissues and byssus were recorded. Highly significant correlations (P<0.01, P<0.05) were observed between tissue and byssal concentrations of Cd, Pb, Ni and Ag. Factor analysis showed clear separation of both the tissue and byssi samples based on their geographic distribution, possibly reflecting a different rate of deposition of clay minerals at the head of the Pomeranian Bay and the Gulf of Gdańsk. The Pomeranian Bay differs from the Gulf of Gdańsk in respect to geological structure of bottom sediments as a substrata for the M. edulis trossulus as well as in relation to various sources of metallic pollutants. From the data obtained in the present study and those reported previously the soft tissue and especially byssus of M. edulis, in contrast to shells, appear to be a significantly better bioindicator for identification of coastal areas exposed to metallic contaminants.     

Non-destructive pollution exposure assessment in the European hedgehog (Erinaceus europaeus): II. Hair and spines as indicators of endogenous metal and As concentrations

The role of hair and spines of the European hedgehog as non-destructive monitoring tools of metal (Ag, Al, Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn) and As pollution in terrestrial ecosystems was investigated. Our results showed that mean pollution levels of a random sample of hedgehogs in Flanders are low to moderate. Yet, individual hedgehogs may be at risk for metal toxicity. Tissue distribution analyses (hair, spines, liver, kidney, muscle and fat tissue) indicated that metals and As may reach considerable concentrations in external tissues, such as hair and spines. Positive relationships were observed between concentrations in hair and those in liver, kidney and muscle for Al, Co, Cr, Cu, and Pb (0.43 < r < 0.85). Spine concentrations were positively related to liver, kidney and muscle concentrations for Cd, Co, Cr, Cu and Pb (0.37 < r < 0.62). Hair Ag, As, Fe and Zn and spine Ag, Al, As and Fe were related to metal concentrations in one or two of the investigated internal tissues (0.31 < r < 0.45). The regression models presented here may be used to predict metal and As concentrations in internal tissues of hedgehogs when concentrations in hair or spines are available. The present study demonstrated the possibility of using hair and spines for non-destructive monitoring of metal and As pollution in hedgehogs.     

Metal bioaccumulation in the greater white-toothed shrew, Crocidura russula, inhabiting an abandoned pyrite mine site

Hepatic and renal concentrations of iron, magnesium, zinc, lead, copper, manganese, mercury, cadmium, molybdenum, chromium, and nickel were quantified in shrews (Crocidura russula) inhabiting a pyrite mine site in Portugal. Several morphological parameters (body weight, residual index, and relative weights) were also examined to clarify the physiological effects of pollution. Shrews from the mine showed increased bioavailability of Fe, Pb, Hg, Cd, Mo, and Ni in comparison with reference specimens. Adult shrews had the highest Cd levels while Cr and Ni concentrations diminished. Intersexual differences were found for Mo and Ni. As a consequence of metal pollution, the relative hepatic weight was higher in shrews from the mine site when compared with reference specimens. These data indicate that C. russula is a good bioindicator of metal pollution. We also evaluated the toxic effects of Pb, Hg, Cd, and Ni, because several shrews from the polluted site showed high concentrations of these metals. To approximate at the real biological impact of abandoned mines, after this first step it is necessary to associate the bioaccumulation levels and morphological effects with other physiological, ecological and genetical biomarkers.     

Changes in trace metal concentrations in lake water and biota during experimental acidification of Little Rock Lake, Wisconsin, USA

Little Rock Lake, a small (18 ha), low-alkalinity (25 microeq litre(-1), pH 6.1) seepage lake in northern Wisconsin, was divided into two basins by a flexible, inert barrier and, beginning in spring 1985, the north basin was acidified in three 2-year steps to pH 5.6, 5.1 and 4.7. The annual average pH of the reference basin remained near 6.1. As part of a comprehensive programme to determine the chemical and biological responses to acidification, minor metals (Al, Fe, Mn) and trace metals (Cd, Cu, Pb, Zn) in lake water (0.4 microm pore filtered samples), periphyton, zooplankton, and yellow perch (Perca flavescens) were measured. At pH 5.6, dissolved Mn and Fe increased in the acidified basin. At pH 5.1 and 4.7, dissolved Al, Fe, Mn, Cd and Zn were elevated in the acidified basin. At pH 4.7, dissolved Pb in the acidified basin became elevated over reference basin levels. Dissolved Cu remained similar in both basins down to pH 4.7. Cd burdens in periphyton collected on artificial substrates were lower in the treatment basin at pH 5.1 (1.8 microg g(-1) dry wt.) than in the reference basin at pH 6.1 (7.5 microg g(-1) dry wt.), but Al and Fe burdens in periphyton were similar in both basins. Likewise, Cd levels in muscle tissue of perch from the treatment basin at pH 4.7 were lower (26 ng g(-1) dry wt.) than in the reference basin at pH 6.1 (36 ng g(-1) dry wt.); Al and Fe burdens were similar in perch muscle tissue from both basins. Levels of Cd and Fe in zooplankton from the acidified basin at pH 4.7 were approximately equal to 2x higher than in animals from the reference basin. In both basins of the lake, Al and Cd levels in lake biota decreased with increasing trophic level, demonstrating that food chain biomagnification does not occur for these metals.     

The influence of body size, condition index and tidal exposure on the variability in metal bioaccumulation in Mytilus edulis

Mussels are commonly used to monitor metal pollution despite high inter-individual variability in tissue concentrations. In this study, influences of body size, condition index and tidal height on concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were investigated. Body weight was inversely related to metal concentrations and for Cd, Mn, Pb and Zn the regression was affected by tidal height. Except for As, Fe and Mn metal concentrations were inversely related to physiological status though no differences between essential and non-essential metals were obvious. After correcting for body size, tidal height was related positively to As, Cd and Zn, negatively related to Cu, Fe and Mn while Co, Cr, Ni and Pb were independent of tidal height. The study recommends stringent measures during sampling for biomonitoring or metal concentrations at each location must be normalized to a common body size, CI and tidal height.     

Adsorption of trace metals to plastic resin pellets in the marine environment

Plastic production pellets collected from beaches of south west England contain variable concentrations of trace metals (Cr, Co, Ni, Cu, Zn, Cd and Pb) that, in some cases, exceed concentrations reported for local estuarine sediments. The rates and mechanisms by which metals associate with virgin and beached polyethylene pellets were studied by adding a cocktail of 5 μg L(-1) of trace metals to 10 g L(-1) pellet suspensions in filtered seawater. Kinetic profiles were modelled using a pseudo-first-order equation and yielded response times of less than about 100 h and equilibrium partition coefficients of up to about 225 ml g(-1) that were consistently higher for beached pellets than virgin pellets. Adsorption isotherms conformed to both the Langmuir and Freundlich equations and adsorption capacities were greater for beached pellets than for virgin pellets. Results suggest that plastics may represent an important vehicle for the transport of metals in the marine environment.