Spatial and temporal variation in lead levels related to body condition in the Mississippi Valley population of Canada geese

Concern over lead poisoning led to progressive prohibition of toxic shot to harvest waterfowl in the 1980's. Nevertheless, waterfowl remain susceptible to ingestion of lead shot because illegal use continues and spent shot persists in soil and wetland substrates. While mortality due to lead toxicosis has subsided, sublethal effects may still affect survival and reproduction. We measured liver lead levels and body condition in 732 Canada geese (Branta canadensis interior) during July 1984 to April 1989 in southern Illinois (USA), east-central Wisconsin (USA), and northern Ontario (Canada). Although we sampled only individuals that were visibly healthy, 55 of 732 (7.5%) geese had elevated liver lead levels (> 2 ppm). Lead levels of 46 (6.3%) geese indicated subclinical poisoning (2-6 ppm) and 9 (1.2%) geese had lead levels indicative of clinical poisoning (> 6 ppm). A greater proportion of juveniles (14.3%) had elevated lead levels than did adults (6.0%), but there was no difference between genders. Lead levels were highest in autumn and winter in southern Illinois, but were low during nesting and summer, despite legal use of lead shot in northern Ontario during our study. Lead poisoning (> or = 5% of the population) was still evident during all seasons in juveniles, and during autumn and winter in adults, 5 to 10 yr after toxic shot was banned from areas where we collected geese during migration and winter. Elevated lead levels did not affect total body mass, lipid reserves, or mineral levels of geese we collected. Protein levels also were unaffected below 10 ppm, but there was evidence of decline at higher concentrations. Thus, it seems unlikely that lead exposure currently affects survival or reproduction of Mississippi Valley Population (MVP) geese via body condition, although other sublethal effects cannot be discounted.     

Lead shot poisoning of a pacific loon in Alaska

Lead poisoning, associated with ingestion of spent lead shot, was diagnosed in an adult female Pacific loon (Gavia pacifica) observed with partial paralysis on 13 June 2002 and found dead on 16 June 2002 on Kigigak Island, Yukon Delta National Wildlife Refuge, western Alaska, USA. A necropsy revealed three pellets of ingested lead shot in the loon's gizzard and a lead liver concentration of 31 ppm wet weight, which was consistent with metallic lead poisoning. This is the first report of lead poisoning in a Pacific loon and is the only account of lead toxicosis associated with ingestion of lead shot in any loon species breeding in Alaska.     

Paint chip poisoning of Laysan albatross at Midway Atoll

Epizootic mortality occurred in Laysan albatross (Diomedea immutabilis) fledgings at Midway Atoll in 1983. Heavy metal toxicity from ingestion of weathered paint chips was one of the causes. Sick albatrosses were unable to retract their wings, causing a "droop-wing" appearance. Five normal and 12 droop-winged fledglings were captured, killed, and examined. Paint chips found in the proventriculus of the affected fledglings contained up to 144,000 ppm lead. Blood, liver, and kidney concentrations of lead in affected birds were higher than in normal fledglings, and acid-fast intranuclear inclusion bodies were present in the kidneys. Degenerative lesions were present in the myelin of some brachial nerves. Weathered paint samples collected from 12 buildings contained up to 247,250 ppm lead and 101 ppm mercury. Lead poisoning was diagnosed in 10 of the droop-winged albatrosses and was one of the causes of morbidity. Mercury toxicosis and plastic impaction were other possible causes.     

Influence of dietary lead on fluoride bioavailability in the rat

A factorial experiment was conducted with weanling rats fed a purified diet to determine the influence of dietary lead (0 or 100 ppm) as either lead acetate or lead carbonate on fluoride bioavailability (2 or 10 ppm as sodium fluoride). During the 6-wk study, both forms of lead depressed weight gain, regardless of the fluoride level, despite the fact that food intake was similar for all treatment groups. Both forms of lead produced a small, but significant, reduction in femur and second molar fluoride. This effect, however, could only be demonstrated in rats fed diets containing 10 ppm fluoride, indicating a significant interaction between lead and fluoride for these indices of fluoride bioavailability. This interactive effect between fluoride and lead was also demonstrated for apparent fluoride absorption. Both forms of dietary lead significantly increased the lead concentration of plasma, femur, liver, and kidney, and both forms of lead significantly increased the urinary excretion of delta-aminolevulinic acid. The level of dietary fluoride failed to influence these measurements. We therefore conclude that, although small amounts of dietary lead reduce fluoride bioavailability, small amounts of dietary fluoride do not appear to significantly influence the utilization of dietary lead.     

Lead poisoning in a northern bobwhite in Georgia

A northern bobwhite (Colinus virginianus) was observed with partial paralysis on 3 March 1997 and found dead on 8 March 1997 on Di-Lane Plantation Wildlife Management Area (Burke County, Georgia, USA). The juvenile male was necropsied by the Southeastern Cooperative Wildlife Disease Study (Athens, Georgia) and diagnosed with lead toxicosis. The bobwhite had liver tissue lead levels of 399 parts per million wet weight and two worn 1-mm diameter lead shot pellets were found in the gizzard.     

Salt toxicosis in ruddy ducks that winter on an agricultural evaporation basin in California

Agricultural evaporation basins are used as a means to dispose of highly saline underground-tile-drainage water in the San Joaquin Valley (California, USA). The hypersaline water conditions encourage high aquatic invertebrate production, primarily brine shrimp (Artemia franciscana), which attract birds to these sites. Cool winter temperatures (< 4 C) and hypersaline water conditions (> 70,000 mumhos/cm) resulted in feather salt encrustation and salt toxicosis in ruddy ducks (Oxyura jamaicensis). During December 1998 and January 1999, approximately 200 dead and sick ruddy ducks were collected from an evaporation basin and five healthy control ruddy ducks were collected from a freshwater wetland. Brains contained > or = 1,890 ppm sodium (wet tissue mass) in seven dead birds and contained < or = 1,150 ppm sodium in the control birds. Liver arsenic, lead, and mercury concentrations were < 1 ppm in all birds examined. Manganese, molybdenum, and copper liver concentrations did not differ significantly (P > 0.05) between the two groups of ducks. The dead ducks had significantly higher liver selenium, cadmium, iron, and zinc than the controls, but the concentrations were not sufficient to cause toxicity. Significant gross and microscopic lesions in most of the dead birds included conjunctivitis, lens opacity and cataract formation, vascular congestion in various organs most notably in the meninges of the brain, and myocardial and skeletal muscle degeneration.     

Analysis of cadmium and lead

Chronic exposure (3.5 mo) of mice to cadmium (Cd), lead (Pb), or a cadmium-lead mixture at a concentration of 1 ppm in drinking water induced a highly significant inhibition of antibody response to human serum. The highest immunosuppression (84.4%) was induced by the Cd-Pb mixture, whereas Cd caused the lowest immunosuppression (53.6%). The body burden of Cd and Pb in various organs was investigated in the four groups of mice by atomic absorption spectrometry. The highest level of Cd was found in the kidney of the Cd-treated group, and the highest level of Pb was found in the liver of the Pb- and Cd-Pb-treated groups. It is concluded that when mice are exposed concurrently to Cd and Pb, they develop synergistic immunsuppression. Analysis of Cd levels using atomic absorption spectrometry revealed that it was distributed in the following order: kidney>liver>spleen>heart, whereas Pb was distributed in the following order: liver>kidney>spleen>heart.     

Effects of excess dietary selenite on lead toxicity in sheep

The hypothesis that excess dietary selenite ameliorates lead (Pb) toxicosis in domestic sheep was tested. Twenty 6–8-yr-old ewes fed alfalfa pellets were assigned to the following treatments: (1) control; (2) 9.8 mg Pb/kg body weight (b.w.)/d as PbCO₃; (3) 3 mg Se/animal/d as Na₂SeO₃·5H₂O; or (4) a combination of treatments 2 and 3. The gelatin-encapsulated salts were given orally. The study was terminated on d 104, by which time three animals in the Pb group and all five animals in the Pb+Se group had died. All remaining animals were slaughtered on d 104. Lead and Se concentrations were determined in six biweekly-collected blood samples and in soft tissues and bone. Sheep on the control and Se treatments had similar feed intakes, body weights, and tissue Pb levels. Those in the Pb+Se group had lower feed intake, but higher blood Pb values compared with the Pb group. Feeding either element increased (P<0.05) the concentration of that element in blood, kidney, liver, spleen, and bone. Muscle-Pb concentrations were not affected (P<0.05) by treatment. Selenium concentrations in kidney, liver, and muscle were greater (P<0.05), whereas those in heart were less (P<0.05) for the Pb+Se group than for the Se Group. Clinical signs associated with Pb toxicosis noted in other animals were not observed in the poisoned sheep in this study. Selenite did not protect sheep against Pb toxicity and likely served as a synergistic factor.     

Influence of lead in soil on mycorrhizal development and plant growth of Cyamopsis tetragonoloba (Linn.) Taub

Growth of C. tetragonoloba suffered with increase in concentration of Pb in soil. Plant biomass declined significantly at concentrations above 60 ppm of Pb. Roots showed more pronounced impact as compared to shoots. At highest applied concentration of lead (100 ppm), fresh weight of fruits decreased by 33% and dry weight by 52% as compared to control. No significant impact was noticed on the development of mycorrhiza at lower concentrations (15-45 ppm) of lead contamination. At higher concentrations of Pb (60 and 75 ppm), there was a decrease in VAM colonization. VAM hyphae had irregular size and terminated abruptly in outer cortex of root. Number of VAM fungal spores in rhizosphere also decreased with increase in the edaphic Pb concentration.     

Analysis of cadmium and lead: their immunosuppressive effects and distribution in various organs of mice

Chronic exposure (3.5 mo) of mice to cadmium (Cd), lead (Pb), or a cadmium-lead mixture at a concentration of 1 ppm in drinking water induced a highly significant inhibition of antibody response to human serum. The highest immunosuppression (84.4%) was induced by the Cd-Pb mixture, whereas Cd caused the lowest immunosuppression (53.6%). The body burden of Cd and Pb in various organs was investigated in the four groups of mice by atomic absorption spectrometry. The highest level of Cd was found in the kidney of the Cd-treated group, and the highest level of Pb was found in the liver of the Pb- and Cd-Pb-treated groups. It is concluded that when mice are exposed concurrently to Cd and Pb, they develop synergistic immunosuppression. Analysis of Cd levels using atomic absorption spectrometry revealed that it was distributed in the following order: kidney > liver > spleen > heart, whereas Pb was distributed in the following order: liver > kidney > spleen > heart.     

Effects of dietary selenium and of lead on the genesis of spontaneous mammary tumors in mice

Selenium added to the diet significantly lowers the incidence of spontaneous mammary adenocarcinoma in female inbred C3H/St mice infected with the Bittner Milk Factor. Lead, 5 ppm, added to the drinking water in the form of the acetate, diminishes the uptake of selenium and reduces its anticarcinogenic effects, causing mammary tumors to appear with the same high incidence as in Se-unsupplemented controls. At higher lead concentrations in the drinking water (25 ppm), the overall tumor incidence is lowered, but tumor growth is significantly accelerated and the survival of tumor-bearing mice is shortened. Under the conditions of administration chosen, lead acts as a selenium antagonist and lowers the concentrations of selenium in liver, kidney, and spleen. The deposition of selenium, copper, and arsenic in bone is increased as compared to lead-unexposed controls.     

Effect of lead with vitamin E, C, or Spirulina on malondialdehyde, conjugated dienes and hydroperoxides in rats

Lead (100 ppm) was given in doubly deionised water for 30 days to one group of rats. The other groups received lead along with exogenous antioxidants like vitamin E (50 IU/kg), vitamin C (800 mg/kg) or Spirulina (1500 mg/kg) in food for a similar period. Levels of lipid peroxidation products such as malondialdehyde, conjugated diene and hydroperoxide were measured in liver, lung and kidney of treated rats. In lead treated animals there was a significant increase in the levels of these lipid peroxidative products. Administration of exogenous antioxidants in the lead treated animals reduced the levels of malondialdehyde, conjugated diene and hydroperoxide. It indicated that vitamin E, vitamin C and Spirulina had significant (P < 0.001) antioxidant activity thereby protecting the animals from lead induced toxicity.     

Lead exposure in an "urban" peregrine falcon and its avian prey

Necropsy of a 7-yr-resident peregrine falcon (Falco peregrinis) from Baltimore showed a Pseudomonas infection involving the pharynx as the immediate cause of death. Concentrations of lead in liver and kidney measured 0.74 and 1.40 ppm, respectively. A survey of lead exposure was performed on 40 urban rock doves (Columbia livia). Thirteen additional rock doves were collected from sites removed from lead contamination and served as controls. The mean concentration of lead in the blood of the urban rock doves was 0.96 ppm (range 0.29-17.0 ppm) compared to 0.05 ppm (0.01-0.07 ppm) for control birds. Ninety-eight percent (39/40) of the urban rock doves had elevated concentrations of lead in their blood, while 27% (11/40) had sublethal concentrations. None of the control birds had increased concentrations of lead in their blood. Concentrations of lead in liver and kidney of 13 urban rock doves were 3.48 ppm and 9.53 ppm, respectively, compared to concentrations of 0.43 ppm and 0.50 ppm for four control rock doves. From these data a mean total concentration of lead per rock dove was calculated at 4.60 ppm for urban birds and 0.33 ppm for control birds.     

Metabolic interactions between lead and copper in rats ingesting lead acetate

The effects of Pb ingestion with and without concurrent dietary Cu supplementation were determined on parameters associated with Cu deficiency in rats fed a nutritionally adequate diet. Groups of weanling male Sprague-Dawley rats were fed a purified (AIN-′76) diet and given Pb (0 or 500 ppm) and Cu (0, 6, or 12 ppm) as the acetate salt in deionized drinking water for 5 wk. A Pb-induced Cu deficiency resulted that was characterized by decreased levels of Cu in tissue and blood, decreased activities of the Cu-dependent enzymes, ceruloplasmin (serum) and Superoxide dismutase (erythocytes), and increased concentration of Fe in liver. These effects of Pb were prevented completely or in part by concurrent Cu supplementation. The Pb-induced decrease in hemoglobin and hematocrit values and the decrease in weight gain were not prevented by Cu supplementation of the diet and can therefore be assumed to be the direct result of a toxic effect of Pb. Although Pb ingestion resulted in decreased concentration of Cu in blood and tissue, additional dietary Cu had no effect on Pb levels.     

Marine protected area restricts demographic connectivity: Dissimilarity in a marine environment can function as a biological barrier

The establishment of marine protected areas (MPAs) can often lead to environmental differences between MPAs and fishing zones. To determine the effects on marine dispersal of environmental dissimilarity between an MPA and fishing zone, we examined the abundance and recruitment patterns of two anemonefishes (Amphiprion frenatus and A. perideraion) that inhabit sea anemones in different management zones (i.e., an MPA and two fishing zones) by performing a field survey and a genetic parentage analysis. We found lower levels of abundance per anemone in the MPA compared to the fishing zones for both species (n = 1,525 anemones, p = .032). The parentage analysis also showed that lower numbers of fishes were recruited from the fishing zones and outside of the study area into each anemone in the MPA than into each anemone in the fishing zones (n = 1,525 anemones, p < .017). However, the number of self‐recruit production per female did not differ between the MPA and fishing zones (n = 384 females, p = .516). Because the ocean currents around the study site were unlikely to cause a lower settlement intensity of larvae in the MPA, the ocean circulation was not considered crucial to the observed abundance and recruitment patterns. Instead, stronger top‐down control and/or a lower density of host anemones in the MPA were potential factors for such patterns. Our results highlight the importance of dissimilarity in a marine environment as a factor that affects connectivity.     

Temporal and dose-response features in swine fed corn screenings contaminated with fumonisin mycotoxins

Fumonisin B₁ (FB₁), a mycotoxin produced byFusarium moniliforme andF. proliferatum, induces liver damage and pulmonary edema in swine. We examined the temporal and dose-response features of FB₁ toxicosis in male weanling crossbred pigs fed nutritionally balanced diets, containing corn screenings naturally contaminated with fumonisins, for 14 days. Total fumonisins (FB₁ and FB₂) in diets 1 through 6 were assayed at 175, 101, 39, 23, 5, and <1 ppm (below detectable concentrations), respectively. Clinical signs, serum biochemical alterations, and morphologic changes were evaluated. Pigs were weighed, and bled for hematologic and clinical chemistry evaluation on days 5 and 14. They were euthanized on day 14, or earlier if respiratory distress was observed. Respiratory distress developed in 3/5 pigs fed diet 1 between days 4 and 6 due to severe pulmonary edema and pleural effusion. Histologic evidence of hepatic injury was present in all pigs fed diets 1 and 2, 3/5 on diet 3, and 1/5 on diet 4. Serum bilirubin and cholesterol concentrations, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and arginase (ARG) activities were elevated in pigs fed diets 1 and 2. Based on liver histopathology, the no observed adverse effect level (NOAEL) for fumonisin toxicity in swine was <23 ppm total fumosins for the 14-day period. Based on regression analyses of the clinical chemistry profiles at 14 days, the NOAEL was <12 ppm, with ALP being the most sensitive parameter. In conclusion, pulmonary edema occurred only at the highest fumonisin concentration (175 ppm), while liver damage occurred at much lower concentrations with a NOAEL of <12 ppm.Abbreviations ALP alkaline phosphatase - ALT alanine aminotransferase - ARG arginase - AST aspartate aminotransferase - ELEM equine leukoencephalomalacia - FB₁ fumonisin B₁ - GGT gamma-glutamyl transferase - NOAEL no observed adverse effect level     

S-adenosyl-L-methionine a counter to lead intoxication?

The effect of S-adenosyl-L-methionine (SAM) administration to both acute and chronic lead exposed mice was investigated. SAM was given s.c. at different doses and for different time intervals. The best results were obtained using 20 mg SAM/kg applied daily over a period of 20-22 days. Results obtained in both acute and chronic lead poisoning were quite similar. GSH concentration in blood and liver, reduced in intoxicated animals was increased after SAM administration reaching normal values. Blood, liver and kidney lead content notably increased at the beginning of SAM treatment and decreased rapidly in the group receiving SAM, attaining values near control levels in 2 weeks. A significant recovery of blood, liver, kidney, spleen and brain delta-aminolevulic acid dehydratase (ALA-D) initially reduced in poisoned animals, was clearly produced after SAM administration. A clear and direct correlation between the recovery of both ALA-D activity and GSH levels and the decreased concentration of lead in tissues was observed, reinforcing our proposal that enhancement of thiol content as a result of SAM administration would facilitate the detoxification process and lead removal, consequently reversing the inactivation of the enzyme. We conclude that SAM therapy is beneficial in the treatment of lead intoxication.     

The interaction of iron and ascorbic acid with lead in the chick

Three experiments were conducted with chicks to examine the effects of dietary iron and ascorbic acid on the accumulation of lead in various organs. Lead was fed as PbCl₂, 500 or 1000 ppm Pb, iron as FeSO₄·7H₂O, 1000 ppm Fe, and ascorbic acid at 0.5%. Iron was effective in reducing the accumulation of lead in the femur and kidneys at both levels of lead. Ascorbic acid reduced the lead level in the kidneys when the concentration of lead in the diet was 500 ppm, but not at 1000 ppm. The effects of ascorbic acid on bone accumulation was variable. In two experiments the lead concentration was increased and in one it was decreased. These findings may reflect two influences of ascorbic acid found by others, namely an increase in absorption and an increase in urinary excretion. The rapid accumulation of lead in chick bones suggests that it may be an excellent experimental animal for lead studies.     

Weak Compliance Undermines the Success of No-Take Zones in a Large Government-Controlled Marine Protected Area

The effectiveness of marine protected areas depends largely on whether people comply with the rules. We quantified temporal changes in benthic composition, reef fish biomass, and fishing effort among marine park zones (including no-take areas) to assess levels of compliance following the 2005 rezoning of the government-controlled Karimunjawa National Park (KNP), Indonesia. Four years after the rezoning awareness of fishing regulations was high amongst local fishers, ranging from 79.5±7.9 (SE) % for spatial restrictions to 97.7±1.2% for bans on the use of poisons. Despite this high awareness and strong compliance with gear restrictions, compliance with spatial restrictions was weak. In the four years following the rezoning reef fish biomass declined across all zones within KNP, with >50% reduction within the no-take Core and Protection Zones. These declines were primarily driven by decreases in the biomass of groups targeted by local fishers; planktivores, herbivores, piscivores, and invertivores. These declines in fish biomass were not driven by changes in habitat quality; coral cover increased in all zones, possibly as a result of a shift in fishing gears from those which can damage reefs (i.e., nets) to those which cause little direct damage (i.e., handlines and spears). Direct observations of fishing activities in 2009 revealed there was limited variation in fishing effort between zones in which fishing was allowed or prohibited. The apparent willingness of the KNP communities to comply with gear restrictions, but not spatial restrictions is difficult to explain and highlights the complexities of the social and economic dynamics that influence the ecological success of marine protected areas. Clearly the increased and high awareness of fishery restrictions following the rezoning is a positive step. The challenge now is to understand and foster the conditions that may facilitate compliance with spatial restrictions within KNP and marine parks worldwide.     

Surface soil as a potential source of lead exposure for young children.

Soil analyses revealed an elevated lead content in the surface soil of three British Columbia cities. The lead accumulations were largely attributed to dustfall from a nearby large lead-zinc smelter in Trail and to automotive traffic in Nelson and Vancouver. Although the mean concentrations of lead in the soil were relatively low at Nelson (192 parts per million [ppm]), in selected areas of Vancouver with heavy traffic they were similar to those found within 1.6 km of the large smelter at Trail (1545 and 1662 ppm respectively). In a study conducted in 1975, children aged 1 to 6 years in Trail and Nelson were found to have higher mean blood lead levels than grade nine students. The findings of the later study support the view that particulate lead in surface soil and dust accounted for most of the greater lead absorption in the younger children.