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.     

Bioaccumulation of metals and effects of landfill pollution in small mammals. Part I. The greater white-toothed shrew, Crocidura russula

Here we quantified the bioaccumulation of metals (lead, mercury, cadmium, iron, magnesium, zinc, copper, manganese, molybdenum, and chromium) and assessed several morphological (RI, relative weights) and genotoxic parameters as biomarkers of pollution from the landfill of Garraf (Barcelona, NE Spain). Specimens of Crocidura russula (Insectivora, Mammalia) from the landfill site showed increased Pb, Cd, Mg, Zn, Cu, and Cr concentrations in their tissues. Levels of mercury were below detection limits. Concentrations of Cd, Pb, and Cr varied significantly with age and no differences were found between males and females. While no differences were found in morphological parameters between shrews from the two sites, those from the polluted one showed more micronuclei in blood than those from reference site (1.786+/-0.272 vs. 0.088+/-0.045 per thousand; U=46.000, p<0.001). The considerable amounts of potentially toxic metals (Pb till 59.71 and Cd till 56.57microgg(-1) DW in kidneys) and the genotoxic effects indicate the harmful effect on biota. We consider necessary biomonitoring this landfill sited in a partially protected area.     

Metal and metalloid accumulation in shrews (Soricomorpha, Mammalia) from two protected Mediterranean coastal sites

Although ecotoxicological data on heavy metals are abundant, information on other potentially toxic elements with attributed deficiency and/or toxic disturbances is scarce. Here we quantify zinc, copper, iron, manganese, chromium, molybdenum, strontium, barium, and boron in bones of greater white-toothed shrews, Crocidura russula, inhabiting two protected Mediterranean coastal sites: the Ebro Delta, a wetland impacted by human activities, and the Medas Islands, a reference site. Natural and anthropogenic inputs significantly increase Fe, Mn, Mo, Sr, Ba, and B in specimens from the Ebro Delta, whereas Cu and Cr were higher in Medas' shrews. Principal component analysis allowed complete separation between sites along the first two axes in particular due to B, Sr, and Cu. This study provides metal reference values in bones of insectivores, explores their variability and bioaccumulation patterns in depth, and assesses the potential environmental risk and toxicity for biota exposed to the above elements.     

Chronic exposure to environmental stressors induces fluctuating asymmetry in shrews inhabiting protected Mediterranean sites

Many ecotoxicological studies have addressed the effects of contaminant exposure at various levels of biological organization. However, little information exists on the effects of toxicants on wildlife populations. Here we examined exposure of populations of the greater white-toothed shrew Crocidura russula (Soricomorpha, Soricidae) occupying two protected Mediterranean sites (a polluted area, the Ebro Delta, and a control site, Garraf Massif). Bioaccumulation of selected elements (Pb, Hg, Cd, Zn, Cu, Fe, Mn, Cr, Mo, Sr, Ba, and B), a body condition index (BCI) and fluctuating asymmetry (FA) were used to assess the chronic exposure to environmental pollution. BCI was correlated neither to metal concentrations nor to FA, suggesting that this fitness measure only reflects environmental disturbances at a local level. However, shrews from the polluted area showed higher concentrations of metals and metalloids (Pb, Hg, B, and Sr) and greater shape FA than specimens from the reference area. A correlation between FA was found for both first and second principal component vectors suggesting that developmental instability increases as a result of exposure to multiple pollutants. Our results corroborate the suitability of C. russula as a bioindicator of environmental quality and show that FA is an appropriate index to examine impact of developmental stressors in populations inhabiting disturbed areas.     

The combined use of chemical and biochemical markers to assess water quality along the Ebro River

Carp (Cyprinus carpio) and barbel (Barbus graellsii) were collected from five sites along the Ebro River. The study was designed to assess levels of persistent organic pollutants and metals bioaccumulated by fish, and some biochemical responses (cytochrome P450 system, phase II activities, and metallothioneins) against those pollutants. The highest levels of PCBs and DDTs were detected in carp from industrialised areas, which also showed high levels of mercury and cadmium in the liver, and high levels of nonylphenol in bile. Significant alterations in some biochemical markers were observed and associated to combined exposure to pollutants. The activity 7-ethoxyresorufin O-deethylase ranged from 69 pmol/min/mg protein in carp from the reference site to 415 pmol/min/mg protein in those from polluted sites. Carp from the Ebro Delta, an agricultural area, had depressed acetylcholinesterase in muscle tissue. Metallothionein concentrations were positively correlated with copper residues, but no significant differences among sampling points were observed.     

Patterns of mercury and methylmercury bioaccumulation in fish species downstream of a long-term mercury-contaminated site in the lower Ebro River (NE Spain)

Since the 19th century, large amounts of industrial waste were dumped in a reservoir adjacent to a chlor-alkali plant in the lower Ebro River (NE Spain). Previous toxicological analysis of carp populations inhabiting the surveyed area have shown that the highest biological impact attributable to mercury pollution occurred downstream of the discharge site. However, mercury speciation in fish from this polluted area has not been addressed yet. Thus, in the present study, piscivorous European catfish (Silurus glanis) and non-piscivorous common carp (Cyprinus carpio) were selected, to investigate the bioavailability and bioaccumulation capacities of both total mercury (THg) and methylmercury (MeHg) at the discharge site and downstream points. Multiple Correspondence Analysis (MCA) was applied to reduce the dimensionality of the data set, and Multiple Linear Regression (MLR) models were fitted in order to assess the relationship between both Hg species in fish and different variables of interest. Mercury levels in fish inhabiting the dam at the discharge site were found to be approximately 2-fold higher than those from an upstream site; while mercury pollution progressively increased downstream of the hot spot. In fact, both THg and MeHg levels at the farthest downstream point were 3 times greater than those close to the waste dump. This result clearly indicates downstream transport and increased mercury bioavailability as a function of distance downstream from the contamination source. A number of factors may affect both the downstream transport and increased Hg bioavailability associated with suspended particulate matter (SPM) and dissolved organic carbon (DOC).     

Bioaccumulation of metals and effects of a landfill in small mammals. Part II. The wood mouse, Apodemus sylvaticus

We assess the bioaccumulation of metals (Pb, Hg, Cd, Fe, Mg, Zn, Cu, Mn, Mo, Cr) and effects of landfill leachates on morphological (RI, relative weights), plasma (GPT, GOT, creatinine), and genotoxic (MNT) parameters in wood mice, Apodemus sylvaticus, inhabiting close the Garraf landfill site (NE Spain). Due to the high age- and sex-dependent variation in wild populations, we also studied the effect of these biotic factors on the parameters studied. Wood mice from the landfill site, sited in a partially protected area, showed more Cd, Fe, Zn, Cu, Mn, Mo, and Cr than specimens from the reference site. Moreover, mice near the landfill registered low RI and high relative renal weight, GPT, and MN frequency, which indicate that the landfill affects the health of wild mice. In contrast to sympatric shrews from a previous study, wood mice showed lower bioaccumulation of metals and lower variation caused by biotic factors. Moreover, the morphological and physiological alterations demonstrated that they were also more sensitive at environmental pollution. Given the contribution of small mammals to ecosystem function and the scarce ecotoxicological data on the effects of landfill pollution on wild terrestrial mammals, we consider that our study can be used to improve the management of this protected area.     

Zn, Cd and Pb accumulation and arbuscular mycorrhizal colonisation of pennycress Thlaspi praecox Wulf. (Brassicaceae) from the vicinity of a lead mine and smelter in Slovenia

Significant hyperaccumulation of Zn, Cd and Pb in field samples of Thlaspi praecox Wulf. collected from a heavy metal polluted area in Slovenia was found, with maximal shoot concentrations of 14,590 mg kg(-1) Zn, 5960 mg kg(-1) Cd and 3500 mg kg(-1) Pb. Shoot/root ratios of 9.6 for Zn and 5.6 for Cd show that the metals were preferentially transported to the shoots. Shoot bioaccumulation factors exceeded total soil Cd levels 75-fold and total soil Zn levels 20-fold, further supporting the hyperaccumulation of Cd and Zn. Eighty percent of Pb was retained in roots, thus indicating exclusion as a tolerance strategy for Pb. Low level colonisation with arbuscular mycorrhizal fungi (AMF) of a Paris type was observed at the polluted site, whereas at the non-polluted site Arum type colonisation was more common. To our knowledge this is the first report of Cd hyperaccumulation and AMF colonisation in metal hyperaccumulating T. praecox.     

Assessment and potential sources of metals in the surface sediments of the Yellow River Delta,Eastern China

The Yellow River Delta is the most intact estuary wetland in China and suffers from great pressure of metals. Seventy-seven surface sediment samples were collected in the delta, and contents of Cu, Pb, Cd, Cr, Zn, Ni, and Mn were analyzed by inductively coupled plasma spectrometry and those of Hg and As by atomic fluorescence spectrometry. The results showed that means of metal contents (ppm, dry weight) were as follows: Hg, 0.04; Cr, 61.72; Cu, 20.97; Zn, 60.73; As, 9.47; Pb, 21.91; Cd, 0.12; Ni, 27.24; and Mn, 540.48. 43.8% of Hg and 14.3% of Cd were from the allogenic source while others from the authigenic source. The results of the geoaccumulation indexes appeared that 6.5% of sites from the estuarine and the Gudao areas were moderately polluted by Hg. All ecological risk index values of Hg and 37.7% of Cd were more than 40, which were the main factors of strongly and moderately potential ecological risks of 37.7% of sites in the delta. High Cd contents may be due to the alkaline conditions of the delta and the unreasonable management of the farmland, while the abnormal distribution of Hg to the wet or dry deposition and the erosion of the seawater. It was suggested to monitor Hg content in the atmosphere of the Yellow River Delta. The results were expected to update the pollution status of metals in the delta and created awareness of preserving the sound condition of the Yellow River Delta.     

Heavy metal contamination in bats in Britain

Toxic metals are bioaccumulated by insectivorous mammals but few studies (none from Britain) have quantified residues in bats. We measured renal mercury (Hg), lead (Pb) and cadmium (Cd) concentrations in bats from south-west England to determine how they varied with species, sex, age, and over time, and if they were likely to cause adverse effects. Residues were generally highest in whiskered bats (Myotis mystacinus). Compared with other species, pipistrelle (Pipistrellus spp) and Natterer's bats (Myotis nattereri) had significantly lower kidney Hg and Pb concentrations, respectively. Renal Hg increased over time in pipistrelles but the contributory sources are unknown. Kidney Pb did not decrease over time despite concurrent declines in atmospheric Pb. Overall, median renal metal concentrations were similar to those in bats from mainland Europe and 6- to 10-fold below those associated with clinical effect, although 5% of pipistrelles had kidney Pb residues diagnostic of acute lead poisoning.     

Analysis of micronucleated erythrocytes in heron nestlings from reference and impacted sites in the Ebro basin (N.E. Spain)

The frequency of micronuclei (MN) in peripheral erythrocytes was tested for 59 heron nestlings (Ardea purpurea, Egretta garzetta and Bubulcus ibis) sampled at two areas (polluted and reference) on the River Ebro (NE Spain) and at its Delta during Spring 2006. Flow-cytometry analysis revealed higher (three- to six-fold) MN counts in samples from the most polluted site relative to samples from the reference area. Samples from the Delta showed intermediate values. Age, morphometric parameters (weight, tarsus size and bill-head length) and maturation status showed no significant differences among the different populations for each species; nor were they correlated with MN levels. The data suggest that elevated levels of MN in chicks in impacted areas reflected the chemical pollution of their nesting sites. The use of nestlings for this assay appears to be a convenient, non-destructive method to assess the impact of pollution in natural bird populations.     

Metal accumulation and performance of nestlings of passerine bird species at an urban brownfield site

The use of passerine species as bioindicators of metal bioaccumulation is often underutilized when examining the wildlife habitat value of polluted sites. In this study we tested feathers of nestlings of two common bird species (house wren and American robin) for accumulation of Pb, Zn, As, Cr, Cu, Fe in comparison of a polluted, urban brownfield with a rural, unpolluted site. House wren nestlings at the study site accumulated significantly greater concentrations of all target metals except Zn. At the polluted site we found significant species differences of metal concentrations in feathers, with house wrens accumulating greater concentrations of Pb, Fe, and Zn but slightly lesser accumulations of Cr and Cu than American robins. Although house wren nestlings demonstrated significant accumulation of metals, these concentrations showed little effect on size metrics or fledge rates during the breeding season compared to nestlings from the control site.     

Concentrations of heavy metals in Sotalia fluviatilis (Cetacea: Delphinidae) off the coast of Ceará, northeast Brazil

Lead (Pb), cadmium (Cd) and mercury (Hg) concentrations on liver and kidney of Sotalia fluviatilis (Cetacea: Delphinidae) stranded in the coast of Ceará, Brazil, were studied from 1996 to 1999. Pb levels were usually lower than the detection limit (0.1 microg/g). Concentrations of Cd were significantly higher in kidney than liver, averaging 0.8 microg/g. Mercury accumulation took place mainly in liver with an average concentration of 4.6 microg/g. Both metals were significantly higher in larger mature individuals, but differences between sexes were not significant. The detection of Cd, Hg and Pb in tissue samples of S. fluviatilis off the coast of Ceará indicated that heavy metals are locally available in the water, and bioaccumulation may be occurring through the food web. Contamination levels were not considered critical, but could be related to Ceará's growing industrial development. The associated risks of pollution outfalls may pose a threat to marine organisms in a near future, especially for top predators such as S. fluviatilis.     

Effects of heavy metal pollution on red wood ant (Formica s. str.) populations

We studied the species composition, mound population densities, relative abundance and colony sizes of red wood ants along a well known air pollution gradient of a copper smelter in Southwest Finland. The dominant species, Formica aquilonia, was further studied for heavy metal (Al, Cu, Cd, Ni, Zn, As, Pb, Hg) levels and morphological characters (body mass, head width, labial gland disease) of workers. We found five species belonging to Formica s. str., and two of them showed changes in their relative abundance, which could not be explained by natural habitat differences. Nest mound volumes were 34% smaller in the polluted area, suggesting that smaller colonies can be maintained there. The heavy metal levels in F. aquilonia workers were higher in the polluted area for all metals, except Hg. The largest relative differences between the study areas (polluted/unpolluted) were found for As (4.1), Ni (2.4), Cu (2.1) and Pb (1.8). Morphological characters of workers were not related to the heavy metal levels. Our data showed that red wood ants can tolerate relatively high amounts of heavy metals and maintain reproducing colonies even in a heavily polluted area, but on the basis of smaller colony sizes, pollution stress may also cause trade-offs in reproduction.     

Contamination in sediments, bivalves and sponges of McMurdo Sound, Antarctica

This study examined the concentrations of total hydrocarbons (THC), polychlorinated biphenyls (PCB), polyaromatic hydrocarbons (PAH), and trace metals (Cu, Zn, Cd, Pb, Hg and As) in marine sediments off Scott Base (NZ) and compared them with sediments near the highly polluted McMurdo Station (US) as well as less impacted sites including Turtle Rock and Cape Evans. The Antarctic mollusc, Laternula elliptica and three common sponge species were also analysed for trace metals. The mean THC concentration in sediments from Scott Base was 3 fold higher than the pristine site, Turtle Rock, but 10 fold lower than samples from McMurdo Station. McMurdo Station sediments also contained the highest concentrations of PAHs, PCBs and the trace metals, Cu, Zn, Pb, Cd and Hg. Copper was significantly higher in bivalves from McMurdo Station than other sites. Trace metal concentrations in sponges were generally consistent within sites but no spatial patterns were apparent.     

Blood biomarkers and contaminant levels in feathers and eggs to assess environmental hazards in heron nestlings from impacted sites in Ebro basin (NE Spain)

Blood biomarkers and levels of major pollutants in eggs and feathers were used to determine pollution effects in nestlings of the Purple Heron Ardea purpurea and the Little Egret Egretta garzetta, sampled on three Ebro River (NE Spain) areas: a reference site, a site affected by the effluents of a chlor-alkali industry and the river Delta. The two impacted heron populations showed mutually different pollutant and response patterns, suggesting different sources of contamination. In the population nesting near the chlor-alkali plant, elevated levels of hexachlorobenzene (HCB) and polychlorobiphenyls (PCBs) in eggs, and mercury in feathers in A. purpurea chicks were related with reduced blood antioxidant defenses and increased levels of micronuclei. In Ebro Delta, high levels of plasmatic lactate dehydrogenase in A. purpurea chicks and high frequency of micronuclei in blood of both species were tentatively associated with intensive agricultural activities taking place in the area. These results provide the first evidence of a biological response in heron chicks to the release of pollutants at a chlor-alkali plant.     

Health risk assessment of heavy metal exposure through vegetable consumption around a phosphorus chemical plant in the Kaiyang karst area,southwestern China

The phosphorus chemical industry is an important source of heavy metals in farmland. Vegetables grown on contaminated soil potentially impose adverse effects on human health. In this study, the pollution status and health risks of heavy metals in vegetables around a phosphorus chemical plant in Kaiyang County, Guizhou Province, southwestern China, were assessed, and the low-accumulation vegetables were screened by bioaccumulation factor (BAF) and cluster analysis. Results showed the average concentrations of Hg, As, Cd, Pb, Cr, Mn, Co, and Zn in vegetables were 0.015, 0.728 0.382, 0.227, 0.850, 27.227, 0.525, and 6.438 mg/kg, respectively. The single-factor pollution index showed that Cd was moderately polluted, and Cr, Hg, As, and Pb were slightly polluted. The Nemerow pollution index showed that the overall heavy metal pollution was classified as moderately polluted. The accumulation of heavy metals in different vegetables varied greatly, and chard, crown daisy, chayote, pumpkin, eggplant, white radish, sweet potato, carrot, and potato were selected as the low-accumulator vegetables. The consumption of all vegetables except chayote poses both carcinogenic and noncarcinogenic risks; among them, the consumption of sweet potato leaves has the highest health risks. The local population needs to adjust plantation structure and change dietary habits, and government should strengthen the management of phosphorus chemical plant pollution.

     

Estimating the environmental impact of micro-pollutants in the low Ebro River (Spain): an approach based on screening toxicity with Vibrio fischeri

The aim of this study was to assess the likely impacts on the ecosystems due to agricultural, human, and industrial activities carried out in an ecologically important area of the Ebro River (Spain). For it, a screening site specific ecological risk assessment was conducted. Considering the presence of high levels of potentially toxic substances, such as metals and chlorinated organic compounds, aqueous and organic extracts were used to assess toxicity in sediments by using the photo-luminescent bacteria Vibrio fischeri (Microtox) as screening response variable. Sediment samples collected during 2005-2006 in the last course of the Ebro River and its Delta have been analyzed. Toxic responses have shown strong relationships to the levels of pollutants in the area. Moreover, various sites presented some toxicity level, probably because of other factors associated with reducing environments into the sediments. Results indicate that Microtox bioassay is an appropriate tool to perform risk assessment studies at screening level.     

Trace metals and organometals in selected marine species and preliminary risk assessment to human beings in Thane Creek area, Mumbai

Trace metals and organometals were estimated in different types of marine organisms (fish, bivalve, crab and prawn) collected from the Trans-Thane Creek area, Mumbai. Thane Creek area is considered as most polluted area due to industrial discharges. Potential risks associated with consumption of marine organisms collected from this particular area to human beings were assessed. Concentrations of ten trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn) in the edible part of marine organisms were analysed by atomic absorption spectrometer and differential pulse anodic stripping voltametric technique. Methyl mercury and tributyl tin were estimated using gas chromatograph-mass spectrometer in combination with solid phase micro extraction (SPME). An assessment of the risk on human beings due to consumption of marine organism was undertaken using toxic reference benchmark, namely the reference dose (RfD). The hazard index (HI), sum of hazard quotients calculated for all the pollutant showed that the risks from consumption of fish and marine organisms as a whole were generally low and are within safe limits.     

Heavy metals contents in agricultural topsoils in the Ebro basin (Spain). Application of the multivariate geoestatistical methods to study spatial variations

In this work the content of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn) and other parameters (the pH, organic matter, carbonates and granulometric fraction) in agricultural topsoil in the Ebro basin are quantified, based on 624 samples collected according to an 8 by 8 km square mesh. The average concentrations (mg/kg) obtained were: Cd 0.415+/-0.163, Cr 20.27+/-13.21, Cu 17.33+/-14.97, Ni 20.50+/-22.71, Pb 17.54+/-10.41, Zn 17.53+/-24.19 and Hg 35.6+/-42.05 microg/kg. The concentration levels are relatively low in areas of high pH and low organic matter content concentration. The results of factor analysis group Cd, Cu, Hg, Pb and Zn in F1 and Cr y Ni in F2. The spatial heavy metals component maps based on geostatistical analysis, show definite association of these factors with the soil parent material. The local anomalies (found in Cu, Zn and Pb) are attributed to anthropogenic influence.