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At least 685 records · Page 38Linked to original sources
USGS1992

Relating results from earthworm toxicity tests to agricultural soil

The artificial soil tests of the European Economic Community and of the Organization for Economic Cooperation produce data relating earthworm mortality to pesticide concentrations in soil under laboratory conditions. To apply these results to agricultural soils it is necessary to relate these concentrations to amounts of pesticide applied per area. This paper reviews the relevant published literature and suggests a simple relation for regulatory use. Hazards to earthworms from pesticides are suggested to be greatest soon after application, when the pesticides may be concentrated in a soil layer a few millimeters thick. For estimating exposure of earthworms, however, a thicker soil layer should be considered, to account for their movement through soil. During favorable weather conditions, earthworms belonging to species appropriate to the artificial soil test have been reported to confine their activity to a layer about 5 cm. If a 5-cm layer is accepted as relevant for regulatory purposes, then an application of 1 kg/ha would be equivalent to 1-67 ppm (dry) in the artificial soil test.

Book chapter↗
USGS1995

Secondary toxicity in raptors caused by white phosphorus

White phosphorus (WP) has caused waterfowl die-offs in a tidal saltmarsh used by the U.S. Army for artillery practice for > 40 years. Bald (Haliaeetus leucocephalus)and golden (Aquila chrysaetos) eagles have been observed feeding on dead and dying waterfowl on the marsh and may be exposed to WP through ingestion of contaminated birds. One carcass of each eagle species has been found with measurable levels of WP in fat. To determine if raptors can become intoxicated by ingesting prey that have been exposed to WP we fed live, 10-day-old white leghorn chicks three sublethal doses of WP. Six hrs after the last dose we euthanized the chicks and separated them into two groups--one with the digestive system from gizzard anteriorly removed (NoGut) and one with the digestive system intact and a 1.1 mg pellet of WP implanted deep into the crop (Pel). A third group of same-aged chicks unexposed to WP was used for controls. Fifteen kestrels (Fa/co sparverius) were randomly assigned to each of the treatments and 10 to the control diet. By 7 d of the study 8 of the kestrels had died on the Pel and 3 on the NoGut diet. Survivors on the Pel diet had significantly lower hematocrit, hemoglobin, final body weights and greater liver/body weight ratios and weight loss than control birds. The study showed that raptors and possibly other predators are at risk both when consuming flesh of prey that have succumbed to WP poisoning and when ingesting WP pellets that are incorporated in body parts but that the risk is greater when pellets are present.

Book chapter↗
USGS1982

Toxicity of dietary lead in young cockerels

Day-old cockerels received 1850 ppm dietary lead for 4 wks. Blood delta-aminolevulinic acid dehydratase (ALAD) activity was reduced to 1.6% of control activity by the end of the study. Hemoglobin concentration (Hb) in lead-exposed cockerels was significantly less than that of controls at 7, 14, and 28 days, and packed cell volume (PCV) was significantly reduced at 14 days. Blood lead residues reached 832 ug/dl in exposed cockerels; kidney residues were about three times liver residues. At the termination of the study mean body weight of lead-exposed birds was 47% of controls.

Veterinary and Human Toxicology↗
USGS1985

Toxicity to woodlice of zinc and lead oxides added to soil litter

Previous studies have shown that high concentrations of metals in soil are associated with reductions in decomposer populations. We have here determined the relation between the concentrations of lead and zinc added as oxides to soil litter and the survival and reproduction of a decomposer population under controlled conditions. Laboratory populations of woodlice (Porcellio scaber Latr) were fed soil litter treated with lead or zinc at concentrations that ranged from 100 to 12,800 ppm. The survival of the adults, the maximum number of young alive, and the average number of young alive, were recorded over 64 weeks. Lead at 12,800 ppm and zinc at 1,600 ppm or more had statistically significant (p < 0.05) negative effects on the populations. These results agree with field observations suggesting that lead and zinc have reduced populations of decomposers in contaminated forest soil litter, and concentrations are similar to those reported to be associated with reductions in natural populations of decomposers. Poisoning of decomposers may disrupt nutrient cycling, reduce the numbers of invertebrates available to other wildlife for food, and contribute to the contamination of food chains.

Ambio↗
USGS1991

Toxicity of trimethyltin and triethyltin to mallard ducklings

Trimethyltin chloride (TMTC) and triethyltin chloride (TETC) were fed to mallard ( Anas platyrhynchos ) ducklings for 73 to 75 d, beginning when ducklings were 3 to 4 d old. Diets were mixed to contain 0, 0.5, 5 or 50 ppm Sn as either TMTC or TETC. Mortality occurred only in the 5 ppm (2/5 ducklings) and 50 ppm (5/5 ducklings, all dying within 5 d) TMTC groups. Death was preceded by cephalic tremors, lethargy and ataxia; these clinical signs also were observed in surviving ducklings from the 5 ppm TMTC group, but not the 0.5 ppm TMTC group. Ducklings fed 5 and 50 ppm Sn as TMTC exhibited degeneration of the large neurons of the pons, medulla oblongata, gray matter of the spinal cord and pyramidal cells of the cerebral cortex. TETC-fed ducklings showed few signs of clinical toxicosis. Ducklings fed 50 ppm Sn as TETC exhibited mild to severe vacuolization of the white matter of the brain and spinal cord; these lesions were not present in ducklings fed 5 ppm Sn as TETC. Liver, spleen, kidney, thymus, bursa of Fabricius and skeletal muscle presented no abnormal histopathology for either organotin compound. Hematocrit, hemoglobin and plasma aspartate aminotransferase; alanine aminotransferase; lactate dehydrogenase; alkaline phosphatase; and cholinesterase values were determined for the 5- and 50- ppm TMTC and TETC groups, and were not different from those of controls ( p < 0.05). Lesions and clinical signs of toxicosis in ducklings were consistent with those described for mammals exposed to TMTC and TETC. The effect threshold for TMTC in ducklings appears to exceed current environmental concentrations. Environmental concentrations of TETC have not been reported.

Environmental Toxicology and Chemistry↗
USGS2010

The toll of toxics: investigating environmental contaminants

On Earth Day of this year, the British Petroleum-operated Deepwater Horizon oil drilling rig exploded in the Gulf of Mexico, 41 miles off the Louisiana coast. The blast killed 11 workers, injured 17, launched a massive oil spill, and triggered an environmental catastrophe&mdash;the full impact of which may not be realized for years.

Louisiana↗