Pb-Al relationships in waterfowl feces discriminate between sources of Pb exposure

Hunted mallards (n = 56) were collected in the Ebro Delta (Spain) in 2007-08 to evaluate the use of feces as a non-invasive monitoring method to study lead shot ingestion. The prevalence of Pb shot ingestion in these birds was 28.6%, and similar to that reported before a ban on Pb shot use in 2003. Lead concentrations in terminal intestinal contents were higher in mallards with Pb shot in their gizzard. Feces Pb concentrations >34 μg/g d.w were indicative of Pb shot ingestion, and background Pb levels were <12.5 μg/g d.w. To discriminate between birds ingesting soil Pb, and those ingesting Pb shot, we correlated Al and Pb levels and showed that mallards with ingested Pb shot in the gizzard stood out as outliers within the regression. Feces Pb-Al relationships can be used as a simple non-invasive tool in monitoring programs regarding Pb shot ingestion in birds.     

Accumulation in and effects of lead and cadmium on waterfowl and passerines in northern Idaho

Waterfowl and passerines in northern Idaho in 1987 had high levels of lead in their blood and tissues that originated primarily from mining and smelting activities. Four Canada geese (Branta canadensis) and one common goldeneye (Bucephala clangula) found dead contained 8 to 38 microg/g (wet mass) of lead in their livers. These levels exceed the lower lethal limit of 5 microg/g in experimental birds. Two of the Canada geese (one each from the contaminated and reference areas) died with ingested lead shotgun pellets (shot) in their gizzards, whereas the other three birds from the contaminated area contained no ingested shot and evidently died from ingesting environmental lead in sediment or biota. Lead burdens in most American robins (Turdus migratorius) and mallards (Anas platyrhynchos) were high, whereas those in tree swallows (Tachycineta bicolor) were slightly elevated. Lead accumulated to potentially hazardous levels in blood and tissues of some nestling robins (maxima of 0.87 microg/g in blood and 5.6 microg/g in liver) and mallards (maxima of 10.2 microg/g in blood and 2.8 microg/g in liver). In mallards, lead levels and associated physiological characteristics of blood were significantly different in juveniles (HY) versus adults (AHY). Activity of delta-aminolevulinic acid dehydratase (ALAD) was about 87 to 95% lower than values for control birds in experimental studies. Activity of ALAD was significantly inversely correlated with blood lead levels. Cadmium was detected in kidneys of most birds, but even the maximum concentration of 7.5 microg/g in an AHY mallard was below known harmful levels.     

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.     

Lead poisoning in swans in Japan

We investigated the occurrence, source and exposure time of lead poisoning in whooper swans (Cygnus cygnus cygnus) and Bewick's swans (Cygnus columbianus bewickii) in Japan during the winters of 1984-1987. Concentrations of lead in various tissues and physiological evidence of lead shot in some birds indicated that lead shotgun pellets were the source of lead, and exposure occurred after the birds arrived in Japan. Mortality probably occurred within 30 days after exposure to, and retention of, lead shot in the gizzard.     

Investigation into the effects of ingestion of zinc shot by Mallard Ducks (Anas platyrhynchos)

Lead fishing weights and gun shot have been identified as a widespread cause of poisoning of swans and other wildfowl (order Anseriformes). As part of the efforts to find environmentally acceptable substitutes for lead, this paper describes the results obtained from a trial which involved the feeding of zinc shot to groups of mallard (Anas platyrhynchos). Observations of the mallard during the experimental period, post mortem examination, histo-pathological examination and also chemical analysis of liver, kidney and feathers, revealed no ill effects to the dosed birds and indicated that zinc metal in shot from probably presents no detectable health threat to wild birds if ingested.     

Control of lead solubility in soil contaminated with lead shot: effect of soil pH

An incubation experiment was carried out to assess the rate of oxidation of Pb shot and subsequent transfer of Pb to the soil under a range of soil pH conditions. Lead shot corrosion was rapid, so that soil solution and fine earth (<1mm) Pb concentrations increased rapidly within a few months. Corrosion products, dominated by hydrocerussite (Pb(3)(CO(3))(2)(OH)(2)), developed in crusts surrounding individual Pb pellets. However, irrespective of pH, Pb(2+) activities in the soil solutions, modelled using WHAM 6, were much lower than would be the case if they were controlled by the solubility of the dominant Pb compounds present in the Pb shot crust material. In contrast, modelling of soil solid-solution phase distribution of Pb, again using WHAM 6, suggested that, at least during the 24 months of the study, soil solution Pb concentrations were more likely to be controlled by sorption of Pb by the soil solid phase.     

Source-pathway-receptor investigation of the fate of trace elements derived from shotgun pellets discharged in terrestrial ecosystems managed for game shooting

Spent shotgun pellets may contaminate terrestrial ecosystems. We examined the fate of elements originating from shotgun pellets in pasture and woodland ecosystems. Two source-receptor pathways: i) soil-soil pore water-plant and ii) whole earthworm/worm gut contents - washed and unwashed small mammal hair were investigated. Concentrations of Pb and associated contaminants were higher in soils from shot areas than controls. Arsenic and lead concentrations were positively correlated in soils, soil pore water and associated biota. Element concentrations in biota were below statutory levels in all locations. Bioavailability of lead to small mammals, based on concentrations in washed body hair was low. Lead movement from soil water to higher trophic levels was minor compared to lead adsorbed onto body surfaces. Lead was concentrated in earthworm gut and some plants. Results indicate that managed game shooting presents minimal risk in terms of element transfer to soils and their associated biota.     

Lead poisoning of passerines at a trap and skeet range

Our objective was to determine if ground foraging passerines in a woodland surrounding a trap and skeet range were subject to lead poisoning. Lead availability to birds was determined by shot counts and soil and earthworm analysis. Avian exposure to lead was identified by measuring free-erythrocyte protoporphyrin levels in blood and lead in tissues of three passerine species. Results showed that most shot were found in the top 3 cm of soil. Lead measurements ranged from 110 to 27,000 ppm (dry wt) in soil and were 660 and 840 ppm in earthworms. Sparrows held in an aviary at the range (p=0.02) and free-flying juncos (p=0.0005) mist-netted at the range displayed significantly higher protoporphyrin levels than those at an uncontaminated site. Sparrow and cowbird carcasses from the aviary carried 37 and 39 ppm lead (dry wt), respectively, whereas a junco liver contained 9.3 ppm lead.     

Lead induced changes in antioxidant metabolism of horsegram (Macrotyloma uniflorum (Lam.) Verdc.) and bengalgram (Cicer arietinum L.)

One-month old horsegram (Macrotyloma uniflorum (Lam.) Verdc. cv VZM1) and bengalgram (Cicer arietinum L. cv Annogiri) were exposed to different regimes of lead stress as Pb(NO3)2 at 0, 200, 500 and 800 ppm concentrations. The extent of oxidative damage as the rate of lipid peroxidation, antioxidative response and the accumulation of lead in roots and shoots of both plants were evaluated after 12 days of lead stress. Lead (Pb) treated plants showed increased levels of lipid peroxidation as evidenced from the increased malondialdehyde content coupled with the increase in the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), glutathione S-transferase (GST) compared to control (untreated) plants. Lead stress caused significant changes in the activity of antioxidative enzymes. The effect of lead was found to be concentration dependent. Higher concentration of lead (800 ppm) resulted 2- to 3-fold increase in SOD, catalase and peroxidase activities, 3- to 5-fold increase in GR activity and 3- to 4-fold increase in GST activity in roots and leaves of both horsegram and bengalgram plants. Lead stress caused a significant increase in the rate of peroxidation as showed in the levels of malondialdehyde content in roots and leaves of both plant species. Horsegram registered lower Pb accumulation than bengalgram, however localization of Pb was greater in roots than leaves in both plants. In general, lipid peroxide levels and antioxidative enzyme activities were higher in horsegram than bengalgram and also more in roots than leaves which best concordance with the lead contents of both the plants and organs. These results suggest that Pb toxicity causes oxidative stress in plants and the antioxidative enzymes SOD, CAT, POD, GR, GST could play a pivotal role against oxidative injury.     

Preliminary data on changes of lead concentrations in Antarctic ice from 155,000 to 26,000 years BP

Concentrations of lead (Pb) have been measured by ultraclean Isotope Dilution Mass Spectrometry in six sections of the 2083 m Vostok deep Antarctic ice core which integrates some 155,000 years. Lead contamination of 15,000–32,000 pg Pb g⁻¹ existed on the outside of the cores, but measured concentrations decreased abruptly along a radius from the outside to the center of the cores, establishing interior values in the 2–40 pg Pb g⁻¹ range. These interior data show that natural concentrations of Pb have varied strongly in Antarctic ice during the last 155,000 years: Pb values were high during the end of the ice age (Illinois) which proceeded the last interglacial and during the Last Glacial Maximum; they were low during the last interglacial and most of the last ice age (Wisconsin). Soil dust appears to be the major source of natural Pb, but the volcanic contribution is found to be significant during low Pb time periods.     

Grit ingestion as a source of metal exposure in the spruce grouse, Dendragapus canadensis

The objective of this study was to determine if ingestion of grit was a source of metal exposure to the spruce grouse, Dendragapus canadensis. A secondary objective was to assess whether grit could provide a supplemental source of essential minerals to their diet. Ca, P, Mg, S, Zn, Cu, Ni, Co, Cr, Fe, Mn, Al, Pb and Cd of liver (adult, yearling, chicks), crop and gizzard contents (adults) were determined for grouse collected from a relatively pristine boreal forest region of north-central Ontario, Canada. With the exception of Cd liver, concentrations were independent of age [one-way analysis of variance (ANOVA); p>0.004). Zn liver concentrations tended to be greater in adults than yearlings and chicks (one-way ANOVA; p=0.02). Liver concentrations of Cd increased with age (r=0.99; p<0.001). The contribution of crop items to total gizzard elemental content was element specific; crop contents contributed 90-100% of Mn and Zn, 70% for P and Ca, 60% for Pb, 50% for S, and 0-25% for Cu, Mg, Ni, Al, Fe, Co, Cr and Cd to the total elemental concentration of gizzard contents (crop plus grit). Incorporation of grit by grouse could, therefore, constitute an important source of essential macro-(Ca, P, Mg, S) and trace elements (Cu, Fe) but not for Mn or Zn. However, in addition to providing nutrients to the bird, ingestion of grit results in exposure to toxic trace metals such as Cd which in turn is accumulating in the liver. Research directed at determining grit turnover time, and hence metal exposure rates, in bird species which ingest grit to aid in food digestion is required. The toxicological significance of Cd exposure to grit-ingesting birds needs attention.     

The chemical and mineralogical behaviour of Pb in shooting range soils from central Sweden

Recently investigations have shown that the annual flux of lead from shotgun pellets to shooting range soils is significant in some countries. This paper presents the data of chemical and mineralogical analyses of soils and Pb-pellet crusts from five shooting ranges in Sweden and, based on these results, evaluates the retention of lead in these shooting range soils. In the soils, Pb-pellets and bullets are readily decomposed and transformed to crust materials composed of Pb-bearing minerals. The transformation products in the crust materials, identified by X-ray diffraction, are predominantly hydrocerussite [Pb(3)(CO(3))(2) (OH)(2)], associated with cerussite (PbCO(3)) and anglesite (PbSO(4)). In a period of 20-25 years, an average of 4.8% metallic lead in the pellets has been transformed to lead carbonate and lead sulphate, where the former is the more stable mineral in the surface environment. However, in soils relatively rich in humus an average of 15.6% metallic lead in the pellets was transformed to secondary lead compounds in the same period. The results of the chemical analyses indicate that Pb is rather immobile in the soil profile. The surficial horizon contains higher concentrations of lead (52-3400 mg kg(-1)), while lower concentrations of lead were found in the E and B horizons where the total Pb concentrations (8-37 mg kg(-1)) are within about one standard deviation of the mean reference sample concentration. An inverse relationship is revealed between the aluminium hydroxide content of the soil fraction and EDTA-extractable Pb, which suggests that these compounds have affected the retention of lead.     

The quantification and distribution of pollution Pb at a woodland in rural south central Ontario, Canada

Lead concentrations and Pb isotope ratios were measured in the forest floor, mineral soil and vegetation at a white pine and a sugar maple stand in a woodland in south central Ontario. Lead concentrations decreased and 206Pb/207Pb ratios increased with mineral soil depth reflecting the mixing of pollution and natural Pb sources. Lead concentrations and 206Pb/207Pb ratios at 20-30 cm depth were approximately 6-7 mg/kg and 1.31-1.32, respectively. Assuming an integrated 206Pb/207Pb ratio in deposition over time of 1.18, estimated from lichen measurements and published data for the region, approximately 65% of Pb in the surface (0-1 cm) mineral soil is from anthropogenic sources. Approximately 90% of pollution Pb is found in the 0-10 cm soil layer (Ah) and less than 3% of the pollution Pb is present in the forest biomass and mull-type forest floor combined. Despite low Pb concentrations in vegetation (<2.5 mg/kg), we estimate that between 65 and 100% of the Pb in vegetation and approximately 75% of the Pb in the forest floor is from pollution sources. In total, the pollution Pb burdens at the pine and maple stands are estimated to be 860 and 750 mg/m2, respectively.     

Food chain transfer of cadmium and lead to cattle in a lead–zinc smelter in Guizhou, China

Cadmium (Cd) and Lead (Pb) are environmental pollutants. Environmental samples and bovine tissues were collected from the areas around a lead–zinc smelter in Guizhou, China for Cd, Pb, zinc (Zn) and copper (Cu) analysis. Cd in soil (10 mg/kg) and feed (6.6 mg/kg) from the polluted areas was 10 times higher than the Chinese Standards, resulting in higher Cd in bovine kidney (38 mg/kg) and liver (2.5 mg/kg). Pb in feed (132 mg/kg) from the polluted area was much higher than unpolluted areas, causing higher Pb levels in bovine tissues. Environmental Zn was elevated, but bovine tissue Zn was normal. Cu in bovine liver decreased with increased Cd and Pb. Metals in drinking water and in bovine muscle were within the Standard range. Thus, in the areas of this lead–zinc smelter, the environment has been contaminated with Cd and Pb, which has been transferred to cattle through the food chain.     

Lead contamination of seabirds harvested with lead shot--implications to human diet in Greenland

Lead contamination of seabirds from the use of lead shot in Greenland was studied in thick-billed murre hunted at Nuuk in November 1998. In each bird shot pellets were located and counted using X-ray. The birds were skinned and viscera, head, wings and legs removed, after which the carcass was cooked. The soup and breast meat were then analyzed for lead after removal of visible shot pellets. In the soup the lead concentration was quite low, mean 6.3 micrograms/l (95% confidence interval between 4.4 and 8.2 micrograms/l), whereas breast meat lead values have a mean of 0.22 microgram/g (wet weight basis; 95% confidence interval between 0.10 and 0.36 microgram/g). This is more than 10 times higher than in birds not killed with lead shot. We found no correlation between lead concentration measured and number of pellets recorded in the whole bird or in the soup or in meat. The study indicates that lead in the meat exists as small lead fragments, left during the passage of pellets through the breast. Because of inhomogeneous lead distribution in samples, the uncertainty of estimated lead concentration in breast meat is high. Based on this study, it is concluded that birds killed with lead shot are a significant source of lead, probably the most important single source, of the diet of many people in Greenland. We estimate an intake of 50 micrograms lead from eating one boiled murre with soup. In addition people will occasionally eat whole lead shot pellets which have documented health effects. An intake of 50 micrograms lead is about twice as much as the daily average lead intake from all dietary sources in Denmark, about 25 times the daily lead intake from other marine food items in Greenland, and about one-fourth of the accepted tolerable daily intake.     

Systemic review of genetic and epigenetic factors underlying differential toxicity to environmental lead (Pb) exposure

Environmental Science and Pollution Research - Lead (Pb) poisoning is a major public health concern in environmental justice communities of the USA and in many developing countries. There is no...     

Factors influencing lead sorption-desorption at variable added metal concentrations in Rhodoxeralfs

The response of ten soils of the lithic Rhodoxeralf type to the supply of lead at concentrations of 500, 1000, 2000, 3000, 4000, 5000 and 6000 mg kg-1 was examined in batch sorption-desorption tests. Lead availability in the soils was found to depend on its partitioning between the soil solution and the solid phase as reflected in adsorption isotherms. The isotherms, of the H type, were consistent with a high affinity of the sorbent for the metal, with which it forms stable inner-sphere complexes on the soil surface. Sorption-desorption tests revealed that some properties of the soils such as their pH (mean=8) and high contents in clays (particularly in kaolinite) and crystalline iron oxides significantly influence Pb sorption, the effect being especially marked at high added metal concentrations. Added lead is largely retained by crystalline iron oxides and the soil clay fraction; the pH of the soil favours the release of variably-charged sites from both. The extent of Pb desorption was small, particularly at the lowest added levels (500 and 1000 mg kg-1). Desorption increased with increasing added Pb concentration and exceeded 50% at 5000 and 6000 mg kg-1; this suggests that Pb is present not only as inner-sphere complexes, but also as outer-sphere complexes and, partly, as precipitates. The desorption isotherms consist of three segments that exhibit significant differences depending on the added Pb concentration, namely: 500-1000, 2000-4000 and 5000-6000 mg kg-1.     

Lead concentrations in soil, sediment and clam samples from the Pungo River peatland area of North Carolina, USA

Lead (Pb) concentrations were measured in samples of peat soils, sediments and clams (Rangia cuneata) collected from the Pungo River region of coastal North Carolina. In peat soils, mean Pb concentrations (dry weight +/- 1 SD) were significantly higher (p<0.05) in surface samples (12.8microg g(-1)+/-7.6) than in samples from depths of 20 cm (2.7microg g(-1)+/-2.7) or 1 m (3.6microg g(-1)+/-3.6). Mean Pb concentrations in surface sediments from canals draining peatlands and from the Pungo River which receives this drainage ranged from 0.1microg g(-1)+/-0.1 to 7.0microg g(-1)+/-0.6. These Pb concentrations are similar to values reported in other studies for areas considered uncontaminated. Fractionation analysis revealed that the majority of the Pb in the peat and sediment samples was associated with the residual fraction, with lesser amounts in the organically-bound fraction, and generally negligible amounts in the water-soluble fraction. These results indicate that the bulk of the Pb in the soils and sediments of this area is relatively immobile and non-bioavailabe. This is supported by the relatively low concentrations of Pb (0.2-0.5 microg g(-1), dry weight) observed in soft tissues of R. cuneata collected from the Pungo River.     

Geochemical and Pb isotopic evidence for sources and dispersal of metal contamination in stream sediments from the mining and smelting district of Príbram, Czech Republic

Stream sediments from the mining and smelting district of Príbram, Czech Republic, were studied to determine the degree, sources and dispersal of metal contamination using a combination of bulk metal and mineralogical determinations, sequential extractions and Pb isotopic analyses. The highest metal concentrations were found 3-4 km downstream from the main polymetallic mining site (9800 mg Pb kg(-1), 26 039 mg Zn kg(-1), 316.4 mg Cd kg(-1), 256.9 mg Cu kg(-1)). The calculated enrichment factors (EFs) confirmed the extreme degree of contamination by Pb, Zn and Cd (EF>40). Lead, Zn and Cd are bound mainly to Fe oxides and hydroxides. In the most contaminated samples Pb is also present as Pb carbonates and litharge (PbO). Lead isotopic analysis indicates that the predominant source of stream sediment contamination is historic Pb-Ag mining and primary Pb smelting (206Pb/207Pb=1.16), while the role of secondary smelting (car battery processing) is negligible.     

Soil and street dust heavy metal concentrations in and around Cuenca, Ecuador

Lead, cadmium and zinc concentrations have been obtained in a total of 83 soil and dust samples in and around the city of Cuenca, Ecuador. Elevated heavy metal concentrations were observed in the city, with comparable Pb concentrations to those commonly found in European and North American cities. Lead concentrations were also elevated above the estimated regional background (less than 9 microg g(-1)) along a rural track used by about 100 vehicles per day. The extent of the contamination by Cd and Zn was restricted to the urban area.