Factors influencing liver PCB concentrations in sparrowhawks (Accipiter nisus), kestrels (Falco tinnunculus) and herons (Ardea cinerea) in Britain

Large scale temporal and spatial changes in the exposure of terrestrial vertebrates to PCBs have been monitored in the UK by measuring liver residues in sparrowhawks (Accipiter nisus), kestrels (Falco tinnunculus) and grey herons (Ardea cinerea) from throughout the country. Residues in the three species are typically characterised by large intra- and inter-specific variation. Data for 306 sparrowhawks, 186 kestrels and 47 herons collected between 1992 and 1997 as part of a national Predatory Bird Monitoring Scheme were examined to determine how much of this variation was explained by body condition, age and sex, rather than other factors. In all three species, body condition was the single most important factor and accounted for up to 49% of the variation in PCB liver residues; starved birds had the highest liver concentrations. Age and sex were also significant but of lesser importance. Adult sparrowhawks and kestrels had liver PCB residues that were 2 to 10-fold higher than in first-year birds. Sex did not affect residue magnitude in a consistent manner. PCB concentrations in the liver were higher in males than females in both first-year and adult kestrels and in first-year sparrowhawks, but adult female sparrowhawks had similar PCB residues to adult males. Liver residues also varied seasonally. PCB concentrations in first-year sparrowhawks increased during the first year following fledging and a similar pattern was detected in adult female sparrowhawks following egg laying. When these physiological factors were taken into account, it was evident that while kestrels with high fat scores had significantly lower PCB concentrations than either sparrowhawks or herons, liver residues were similar in all three species when birds were in a starved condition. Overall during 1992-1997, the combined influence of body condition, age and sex explained more of the variation in liver PCB concentrations than species differences or other factors, such as geographical variation in exposure.     

Polychlorinated biphenyls and organochlorine pesticides in various bird species from northern China

Little data are available on organochlorine contamination in Chinese terrestrial birds of prey. This study examined the presence of PCBs, DDTs and other organochlorine pesticides in various raptors from northern China. DDE exhibited the highest concentrations among targeted compounds. Greatest levels (23.5-1020 mg/kg lipid weight) were observed in Eurasian sparrowhawks. This may be due to their stopover in southeastern China, where high DDT and dicofol applications have been documented. Residential kestrels exhibited much lower DDE, but similar PCB and HCH concentrations. ΣTEQs and PCB-126/-77 concentration ratios exhibited significant positive correlations with ΣPCB concentrations, respectively. Similar results were also demonstrated by a meta-analysis of previously published data across avian species. Possible hepatic sequestration of coplanar PCB-77, -126, -169 and -118 was observed as liver TEQs increased in Eurasian sparrowhawks. These observations may indicate an induction of CYP1A enzymes, as a result of elevated contamination in some species.     

Arsenic contamination in wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) on abandoned mine sites in southwest Britain

Arsenic can be highly toxic to mammals but there is relatively little information on its transfer to and uptake by free-living small mammals. The aim of this study was to determine whether intake and accumulation of arsenic by wild rodents living in arsenic-contaminated habitats reflected environmental levels of contamination and varied between species, sexes and age classes. Arsenic concentrations were measured in soil, litter, wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) from six sites which varied in the extent to which they were contaminated. Arsenic residues on the most contaminated sites were three and two orders of magnitude above background in soil and litter, respectively. Arsenic concentrations in the stomach contents, liver, kidney and whole body of small mammals reflected inter-site differences in environmental contamination. Wood mice and bank voles on the same sites had similar concentrations of arsenic in their stomach contents and accumulated comparable residues in the liver, kidney and whole body. Female bank voles, but not wood mice, had significantly higher stomach content and liver arsenic concentrations than males. Arsenic concentration in the stomach contents and body tissues did not vary with age class. The bioaccumulation factor (ratio of arsenic concentration in whole body to that in the diet) in wood mice was not significantly different to that in bank voles and was 0.69 for the two species combined, indicating that arsenic was not bioconcentrated in these rodents. Overall, this study has demonstrated that adult and juvenile wood mice and bank voles are exposed to and accumulate similar amounts of arsenic on arsenic-contaminated mine sites and that the extent of accumulation depends upon the level of habitat contamination.     

Variation of heavy metals within and among feathers of birds of prey: effects of molt and external contamination

In this study we examined the effect of external contamination on the heavy metal (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) concentration in feathers. We compared the heavy metal content among the 10 primary wing feathers of sparrowhawks (Accipiter nisus), little owls (Athene nocta) and barn owls (Tyto alba) and the variation within the outermost tail feather of sparrowhawks and tawny owls (Strix aluco). The concentration of Hg was significantly higher in feathers molted first, suggesting that levels in feathers reflect levels in the blood during formation. For some other elements (Al, Co, Ni, Pb, Zn) on the other hand, there are strong indications that external contamination may have an important impact on the levels detected in the feathers. This should be taken into account in future monitoring studies.     

Brominated flame retardants and organochlorine pollutants in aquatic and terrestrial predatory birds of Belgium: levels, patterns, tissue distribution and condition factors

Liver and muscle samples from 7 species of aquatic and terrestrial predatory birds from Flanders (Belgium) were analysed for polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and organochlorine pesticides (OCPs). PCBs were the predominant compounds in our samples, which showed highest concentrations in the liver of barn owl (Tyto alba) and sparrowhawk (Accipiter nisus) (up to 1000 microg/g lipid weight). PBDEs could be determined in most samples at lower concentrations than PCBs (up to 64 microg/g lipid in sparrowhawk liver). Sparrowhawks had the highest levels of hexachlorobenzene, DDTs and PBDEs. In contrast, kestrels (Falco tinnunculus) had relatively low levels of most measured organochlorines. BDE 47 was the most abundant congener in heron (Ardea cinerea) and grebe (Podiceps cristatus), while BDE 47, 99 and 153 were equally important in the terrestrial species. BDE 183 and BDE 209 were only measured in the terrestrial birds. These results indicate that terrestrial birds may be more exposed to higher brominated BDE congeners than aquatic species.     

Long-term trends in organochlorine and mercury residues in some predatory birds in Britain

Residue levels of organochlorine pesticides (HEOD, DDE), polychlorinated biphenyls (PCBs) and mercury (Hg) in the livers of five predatory bird species were monitored in Britain over a 28-year (1963-1990) period. Of two raptor species, sparrowhawks contained higher levels of most chemicals than did kestrels. Among three fish-eaters, herons and kingfishers contained the highest levels of DDE and HEOD, while herons and great-crested grebes contained the highest levels of PCBs and mercury. Species differences were related partly to diet and habitat. In sparrowhawks and kestrels, residues of HEOD and DDE were higher in eastern, arable districts than elsewhere, especially in the 1960s and 1970s. In the fish-eaters, similar regional differences in residue levels were apparent in herons, especially in the 1970s, but not in the other species, for which samples were smaller. Over the 28 years, most species showed significant downward trends in HEOD, DDE and Hg levels, but only two fish-eaters showed significant declines in PCB levels. The downward trends in DDE and HEOD followed successive restrictions in the use of organochlorine pesticides, and were accompanied by recoveries in the populations and breeding success of affected species. Downward trends in mercury were associated with reductions in both agricultural use and industrial emissions.     

Arsenic accumulation in the liver tissue of marine mammals.

Arsenic concentrations were determined in livers of 226 individuals representing 16 different marine mammal species to elucidate its accumulation with age, sex, and feeding habits. Arsenic concentrations varied widely among species and individuals, and ranged from < 0.10 to 7.68 micrograms g-1 dry weight. Marine mammals feeding on cephalopods and crustaceans contained higher arsenic concentrations than those feeding on fishes. No significant gender difference in arsenic concentration was found for almost all the species. Also, no apparent trend with age (or body length) in arsenic accumulation was found for most of the species. It was noted that two seal species, Baikal seal and Caspian seal, from landlocked water environments, contained lower arsenic concentrations than the marine species. To our knowledge, this is the first comprehensive study of arsenic accumulation in a wide range of marine mammal species.     

Decabromodiphenylether and hexabromocyclododecane in wild birds from the United Kingdom, Sweden and The Netherlands: Screening and time trends

The brominated flame retardant decabromodiphenylether (DBDE) was analysed in wild birds to identify the most suitable species for monitoring time trends in DBDE contamination. This information was later used for the design of a 10-year trend study on DBDE in the European Union. DBDE was measured in muscle tissue, liver, and eggs from 10 terrestrial and four aquatic bird species. DBDE was detected in 47% of the terrestrial bird samples (nine species) and in 9% of the aquatic bird samples (six species). Peregrine falcon and sparrowhawk specimens were selected as most suitable species to determine temporal trends of DBDE. For sparrowhawks, no significant change in DBDE concentrations between 1973 and 2001 was found, although in later years more DBDE concentrations were above the detection limit. Peak DBDE levels measured in peregrines in 1995, were followed by a decline in concentrations until 2001. The same species were used for a trend study on hexabromocylcododecane (HBCD). Twenty-four percent of peregrine falcon eggs and 12% of sparrowhawk muscle samples demonstrated measurable HBCD residues. Three diastereomers of HBCD were analysed and the α-diastereomer was the predominant one in most samples. No clear time trends were observed for HBCD in either species. This study demonstrated that these DBDE and HBCD are bioavailable to birds of Northern Europe, although bioaccumulation seems to occur to a limited extent.     

Biomonitoring environmental contaminants near a municipal solid-waste combustor: a decade later

During the 1999 nesting season, eggs and nestlings of anhingas (Anhinga anhinga) and white ibises (Eudocimus albus) were collected from a colony located on the site of a municipal solid-waste (MSW) combustor and analyzed for residues of chemicals potentially released from this facility. Concentrations of most residues, including tetrachlorodibenzo-p-dioxin (TCDD). tetrachlorodibenzofuran (TCDF), arsenic, beryllium, cadmium and lead, were at levels comparable to those found during a similar survey done in 1989, prior to facility start-up. Nickel residues were detected only sporadically in anhingas and in eggs from ibises, and decreased significantly in concentration in ibis nestlings in 1999 compared to 1989. While concentrations of mercury in anhinga nestlings and in eggs of both species were comparable to 1989 levels, its concentration was significantly greater in ibis nestlings in 1999. However, levels of mercury in the ibises remained relatively low when compared to birds from other areas of Florida and did not appear to represent a health threat. While lead did not increase in 1999, its concentration in ibis nestlings remained a concern. The most notable temporal trend observed in birds at this site was a general monotonic decrease in levels of selenium residues during the 10-year monitoring period.     

Arsenic in the food chains of a revegetated metalliferous mine tailings pond.

The environmental distribution, transfer and ecotoxicological risk associated with arsenic in a grassland ecosystem established on metalliferous mine tailings has been determined. High levels of arsenic in the mine tailings (630 +/- 34 mg kg-1) were not reflected in live vegetation due to the physico-chemical nature of the tailings which mitigate against plant uptake. However, elevated levels of arsenic were associated with plant litter. Low concentrations of arsenic in herbivorous invertebrates mirrored those found in their food, although there was evidence of minor detrivoral food chain transfer. Dietary exposure of small mammals to arsenic was well below that demonstrated to induce a toxicological response, and tissue concentrations were consistently below analytical detection limits. There appears to be little ecotoxicological risk associated with arsenic residues at the mine site investigated.     

Accumulation, transformation, and release of inorganic arsenic by the freshwater cyanobacterium Microcystis aeruginosa

Arsenic (As) as a major hazardous metalloid was affected by phytoplankton in many aquatic environments. The toxic dominant algae Microcystis aeruginosa was exposed to different concentrations of inorganic arsenic (arsenate or arsenite) for 15 days in BG11 culture media. Arsenic accumulation, toxicity, and speciation in M. aeruginos as well as the changes of As species in media were examined. M. aeruginosa has a general well tolerance to arsenate and a definite sensitivity to arsenite. Additionally, arsenate actively elevated As methylation by the algae but arsenite definitely inhibited it. Interestingly, the uptake of arsenite was more pronounced than that of arsenate, and it was correlated to the toxicity. Arsenate was the predominant species in both cells and their growth media after 15 days of exposure to arsenate or arsenite. However, the amount of the methylated As species in cells was limited and insignificantly affected by the external As concentrations. Upon uptake of the inorganic arsenic, significant quantities of arsenate as well as small amounts of arsenite, DMA, and MMA were produced by the algae and, in turn, released back into the growth media. Bio-oxidation was the first and primary process and methylation was the minor process for arsenite exposures, while bioreduction and the subsequent methylation were the primary metabolisms for arsenate exposures. Arsenic bioaccumulation and transformation by M. aeruginosa in aquatic environment should be paid more attention during a period of eutrophication.     

Arsenic in sediments from the southeastern Baltic Sea

Arsenic occurs as a persistent constituent in many of the chemical weapons dumped into the Baltic Sea; it can be used as an indicator of leakage and dispersal of released munitions to the marine environment. Total arsenic was analysed in sediment samples taken from the Lithuanian economic zone in the Baltic Sea, which included samples from the chemical munitions dumpsite in the Gotland Basin and national monitoring stations in the southeastern Baltic Sea. Arsenic concentrations in sediments ranged from 1.1 to 19.0 mg kg(-1), with an average of 3.4 mg kg(-1). Although there was evidence of slightly elevated arsenic content in sediments near the weapons dumpsite, arsenic concentrations were nevertheless quite low relative to other investigations in the Baltic and North Seas.     

Temporal and spatial variation of arsenic species in the Dahuofang reservoir in northeast China

Overlying water, pore water, and sediment samples were collected from the Dahuofang reservoir in November 2011 and April 2012, respectively. Total arsenic and arsenic species including arsenite, arsenate, monomethylarsonic, and dimethylarsinic were analyzed by ICP-MS and HPLC–ICP-MS. The results indicated that the environments of the Dahuofang reservoir were in reduced conditions, arsenite was the predominant species in pore water and sediments in the reservoir. Arsenic concentrations in overlying water were very low in all the samples but showed different trend during the different time. In November, arsenic concentrations in the reservoir inlet were higher than that in the other sites, whereas arsenic showed accumulation from the upstream to downstream of the reservoir in samples collected in April. In pore water, arsenic concentrations were about 23 and 37 times higher than those in overlying water in November and April, respectively, and relatively high levels of arsenite were also detected in the pore water. In surface sediments, total arsenic and arsenic species content in the reservoir inlet showed the following decreasing order: R1?>?R10?>?R4. The results also showed that moderate ecological risks exist in pore water and sediments in the Dahuofang reservoir.     

Lead concentrations in birds of prey in Britain

This paper reports on lead (Pb) concentrations in the livers of 424 individuals of 16 raptor species found dead and sent for analysis to the Institute of Terrestrial Ecology, Monkswood, from the early 1980s to the early 1990s. Elevated Pb concentrations in liver (>20 ppm dry wt), within the range associated with Pb poisoning mortality in raptors, were recorded in one peregrine (4% of species sample) and one buzzard (2% of species sample). These birds are likely to have ingested lead gunshot in the flesh of their prey. Another one each of these species had liver Pb concentrations of 15-20 ppm dry wt, reflecting unusually high absorption of Pb. No individuals of any other species had >15 ppm dry wt liver Pb, although some had 6-15 ppm. The source of Pb in these birds was unknown, but it could have resulted from high Pb concentrations in prey items, including some containing lead shot. Median liver Pb concentrations were generally very low (ranging from <0.07 to 1.61 ppm dry wt for species with sample sizes exceeding 10). In sparrowhawks, for which a large sample was available, liver Pb concentrations in all but one individual were low (<2.6 ppm dry wt). Pb concentrations in juveniles were significantly lower than in adults, and were lowest in recently fledged birds.     

Levels and distribution of polybrominated diphenyl ethers in various tissues of birds of prey

In the present study, concentrations and tissue distribution of polybrominated diphenyl ethers (PBDEs; IUPAC # 28, 47, 99, 100, 153, 154, 183, and 209) were examined in brain, adipose tissue, liver, muscle, and serum of birds of prey. Median SigmaPBDE levels (BDE 28-183) in the tissues of sparrowhawks ranged from 360 to 1900 ng/g lipid weight (lw), which was in general one order of magnitude higher than in the tissues of common buzzards (26-130 ng/g lw). There were no differences in PBDE congener patterns between the various tissues within individuals of a certain species. Inter-species differences in PBDE patterns and in particular the percentage of BDE 99, 100 and 153 were, however, pronounced between sparrowhawk and common buzzard. BDE 209 was detected in nearly all serum and in some liver samples, but not in any other tissues. This observation suggests that exposure to BDE 209 is low or that this congener is poorly accumulated. Passive (lipid content related) diffusion could not completely describe the PBDE tissue distribution, e.g. the lowest PBDE-load was measured in brain, a fairly lipid rich tissue.     

Total arsenic accumulation in edible pods and seeds of Phaseolus vulgaris.

The main objective of this study was to evaluate whether arsenic accumulated in the edible pods and seeds of Phaseolus vulgaris, cv. Helda, above the Spanish maximum recommended concentration for food crops, 1 mg kg(-1) on a fresh weight basis. Only organic arsenicals were used because they are: a) the only arsenic species allowed for agricultural applications and b) more mobile than inorganic species. Selection of French beans, a sensitive plant to arsenic, was based on the fact that arsenic upward translocation is higher in sensitive than in tolerant plants. A 2 x 3 factorial experiment was conducted with two organic arsenic species: methylarsonic acid (MAA) or dimethylarsinic acid (DMAA) and three arsenic concentrations: 0.2, 0.5, or 1.0 mg L(-1). Arsenic phytotoxicity was primarily determined by soluble arsenic concentration. Experimental results showed that the low bean plant tolerance to arsenic is possibly due to the high arsenic upward transport to shoots, which could result in profound negative metabolic consequences. Even under extremely adverse conditions, arsenic residues in edible beans were below the maximum statutory limit set by the Spanish legislation. It can be concluded that the major danger of organic arsenical herbicides is that of decreased productivity rather than high arsenic uptake by consumers.     

Occurrence and biomagnification of organohalogen pollutants in two terrestrial predatory food chains

Organohalogen pollutants (OHPs), including dichlorodiphenyl trichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and dechlorane plus (DP), were determined in three raptor species, namely, the common kestrel (Falco tinnunculus), eagle owl (Bubo bubo), and little owl (Athene noctua), as well as in their primary prey items: Eurasian tree sparrow (Passer montanus) and brown rat (Rattus norvegicus). DDTs were the predominant pollutants in avian species followed by PBDEs and PCBs, then minimally contribution of HBCDs and DP. Inter-species differences in the PBDE congener profiles were observed between the owls and the common kestrels, with relatively high contributions of lower brominated congeners in the owls but highly brominated congeners in the kestrels. This result may partly be attributed to a possible greater in vivo biotransformation of highly brominated BDE congeners in owls than in kestrels. α-HBCD was the predominant diastereoisomer with a preferential enrichment of (−)-enantiomer in all the samples. No stereoselective bioaccumulation was found for DP isomers in the investigated species. Biomagnification factor (BMF) values were generally higher in the rat−owl food chain than in the sparrow−kestrel food chain. Despite this food chain-specific biomagnification, the relationships between the log BMF and log K_OW of PCBs and PBDEs followed a similar function in the two food chains, except for BDE-47, -99, and -100 in the sparrow−kestrel feeding relationship.     

Arsenic accumulation by two brake ferns growing on an arsenic mine and their potential in phytoremediation

In an area near an arsenic mine in Hunan Province of south China, soils were often found with elevated arsenic levels. A field survey was conducted to determine arsenic accumulation in 8 Cretan brake ferns (Pteris cretica) and 16 Chinese brake ferns (Pteris vittata) growing on these soils. Three factors were evaluated: arsenic concentration in above ground parts (fronds), arsenic bioaccumulation factor (BF; ratio of arsenic in fronds to soil) and arsenic translocation factor (TF; ratio of arsenic in fronds to roots). Arsenic concentrations in the fronds of Chinese brake fern were 3-704 mg kg-1, the BFs were 0.06-7.43 and the TFs were 0.17-3.98, while those in Cretan brake fern were 149-694 mg kg-1, 1.34-6.62 and 1.00-2.61, respectively. Our survey showed that both ferns were capable of arsenic accumulation under field conditions. With most of the arsenic being accumulated in the fronds, these ferns have potential for use in phytoremediation of arsenic contaminated soils.     

TOTAL ARSENIC ACCUMULATION IN EDIBLE PODS AND SEEDS OF PHASEOLUS VULGARIS

The main objective of this study was to evaluate whether arsenic accumulated in the edible pods and seeds of Phaseolus vulgaris, cv. Helda, above the Spanish maximum recommended concentration for food crops, 1 mg kg^?1 on a fresh weight basis. Only organic arsenicals were used because they are: a) the only arsenic species allowed for agricultural applications and b) more mobile than inorganic species. Selection of French beans, a sensitive plant to arsenic, was based on the fact that arsenic upward translocation is higher in sensitive than in tolerant plants. A 2 × 3 factorial experiment was conducted with two organic arsenic species: methylarsonic acid (MAA) or dimethylarsinic acid (DMAA) and three arsenic concentrations: 0.2, 0.5, or 1.0 mg L^?1. Arsenic phytotoxicity was primarily determined by soluble arsenic concentration. Experimental results showed that the low bean plant tolerance to arsenic is possibly due to the high arsenic upward transport to shoots, which could result in profound negative metabolic consequences. Even under extremely adverse conditions, arsenic residues in edible beans were below the maximum statutory limit set by the Spanish legislation. It can be concluded that the major danger of organic arsenical herbicides is that of decreased productivity rather than high arsenic uptake by consumers.     

Comparison of arsenic content in pelletized poultry house waste and biosolids fertilizer

Managers of human biosolids have been incorporating the practice of waste pelletization for use as fertilizer since the mid 1920s, and waste pelletization has recently been embraced by some poultry producers as a way to move nutrients away from saturated agricultural land. However, the presence of arsenic in pelletized poultry house waste (PPHW) resulting from the use of organoarsenical antimicrobial drugs in poultry production raises concerns regarding additional incremental population exposures. Arsenic concentrations were determined in PPHW and pelletized biosolids fertilizer (PBF) samples. Pellets were processed using strong acid microwave digestion and analyzed by graphite furnace atomic absorption spectroscopy. The mean arsenic concentration in PPHW (20.1 ppm) fell within the lower part of the range of previously report arsenic concentrations in unpelletized poultry house waste. Arsenic concentrations in PBF, the source of which is less clear than for PPHW, were approximately a factor of 5 times lower than those in PPHW, with a mean concentration of 4.1 ppm. The pelletization and sale of these biological waste fertilizers present new pathways of exposure to arsenic in consumer populations who would otherwise not come into contact with these wastes. Arsenic exposures in humans resulting from use of these fertilizer pellets should be quantified to avoid potential unintended negative consequences of managing wastes through pelletization.