Measurements of toxicity and critical stages of development
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Book chapter↗
Geology topics
D. J. Hoffman
Publications and source records attributed to D. J. Hoffman.
Biomarkers of contaminant exposure in common terns and black-crowned night herons in the Great Lakes
Morphological and biochemical indexes of contaminant exposure were examined in hatching common terns ( Sterna hirundo ) and black-crowned night herons ( Nycticorax nycticorax ) from industrialized and nonindustrialized locations in the Great Lakes. In 1984, naturally incubated, pipping common tern and black-crowned night heron embryos collected from industrialized locations exhibited smaller femur-length-to-body-weight ratios, elevated hepatic microsomal aryl hydrocarbon hydroxylase (AHH) activities, and lower hepatic DNA concentrations ( P < 0.05). In addition, a high incidence of subcutaneous edema was noted in pipping herons ( P < 0.01). In 1985, reduced hatching success was observed for laboratory-incubated common tern eggs collected from the industrialized sites, compared to nonindustrialized sites ( P < 0.01). Day-old hatchlings exhibited reduced femur-length-to-body-weight ratio, developmental anomalies, and elevated hepatic AHH activity ( P < 0.05). For hatching common terns studied in 1984 and 1985, femur-length-to-body-weight ratio was inversely related to AHH activity ( r = −0.67, P < 0.05) and inversely related to log-transformed PCB concentrations ( r = −0.70, P ≤ 0.05) of unincubated eggs from the same colony. The activity of AHH in hatching terns was also directly related ( r = 0.71, P ≤ 0.05) to log-transformed PCB concentrations in unincubated eggs. Other examined contaminants, including DDE, other organochlorine pesticides, and mercury, were not directly related to these effects.
Environmental Toxicology and Chemistry↗
Morphological, biochemical, and histopathological indices and contaminant burdens of cotton rats (Sigmodon hispidus) at three hazardous waste sites near Houston, Texas, USA
Male cotton rats (Sigmodon hispidus) were studied at three industrial waste sites near Houston, Texas, to determine whether various morphological, biochemical, and histopathological indices provided evidence of contaminant exposure and toxic insult. Only modest changes were detected in cotton rats residing at waste sites compared with reference sites. No single parameter was consistently altered, except hepatic cytochrome P-450 concentration which was lower ( [Formula: see text] ) at two waste sites, and tended to be lower ( [Formula: see text] ) at a third waste site. Elevated petroleum hydrocarbon concentrations were detected in rats at one waste site, but contaminant burdens of rats from the other sites were unremarkable. Unlike rats captured in summer, those trapped in winter exhibited hepatocellular hypertrophy and up to a 65% increase in liver: body weight ratio, cytochrome P-450 concentration, and activities of aniline hydroxylase, aryl hydrocarbon hydroxylase, and glutathione S-transferase. Although genotoxicity has been previously documented in cotton rats residing at two of the waste sites, biomarkers in the present study provided little evidence of exposure and damage
Environmental Pollution↗
Effects of dietary boron and arsenic on the behavior of mallard ducklings
High concentrations of boron and arsenic have been associated with irrigation drain water and aquatic plants consumed by waterfowl. Both compounds affect the central nervous system and cause generalized physiological distress in mammals and waterfowl. We examined sublethal effects of boron and arsenic on the behavior of developing mallard ducklings (Anas platyrhynchos). Day-old ducklings received an untreated diet (control) or a diet containing 100, 400, or 1,600 ppm boron, added as boric acid, or 30, 100, or 300 ppm arsenic, added as sodium arsenate. Activity schedules and behavior durations were analyzed for effects at the various treatment levels. Both boron and arsenic at the highest levels had significant effects on the activity schedules of developing ducklings, including increased time at rest and under the provided heat lamp. We also observed decreases in the amount of time treated ducklings spent in alert behaviors and in the water in comparison to control ducklings. High levels of boron (1,600 ppm) increased feeding time overall but did not increase the amount of food consumed. Arsenic had no effect on feeding behavior. There were no differences found in the durations of behaviors as a result of treatment. These findings, in combination with reported effects on the growth and physiology of ducklings under identical treatments, suggest that reported concentrations of these compounds in aquatic plants in the Central Valley of California could adversely affect normal duckling development and survival.
Environmental Toxicology and Chemistry↗
Interactive effects of boron, selenium, and dietary protein on survival, growth and physiology in mallard ducklings
High concentrations of boron (B) and selenium (Se) have been found in aquatic food chains associated with irrigation drainwater. Total biomass of invertebrates, a major source of protein for wild ducklings, is sometimes diminished in agricultural drainwater ponds contaminated with Se and B. Day-old mallard ( Anas platyrhynchos ) ducklings received an untreated diet (controls) containing 22% protein or diets containing 15 ppm (μg/g) Se (as selenomethionine), 60 ppm Se, 1,000 ppm B (as boric acid), 15 ppm Se with 1,000 ppm B, or 60 ppm Se with 1,000 ppm B. In a concurrent experiment, the above sequence was repeated with a protein-restricted (7%) but isocaloric diet. After four weeks, blood and tissue samples were collected for biochemical and histological examination. With 22% protein and 60 ppm Se in the diet, duckling survival and growth was reduced and histopathological lesions of the liver occurred. Boron alone caused some reduction in growth. Several interactive effects occurred between B and Se, including further reduction in growth, and increases in plasma glutathione reductase activity, hematocrit, hemoglobin and plasma protein concentrations. With 7% protein, the growth of controls was less than that with 22% protein, 60 ppm Se caused 100% mortality, and growth effects of 15 ppm Se and 1,000 ppm B alone were more pronounced than with 22% protein. Selenium accumulation increased in the liver with 7% protein. Interactive effects were greater for Se and B with 7% protein than with 22% protein and included significant mortality and enhanced accumulation of Se in the liver. These findings suggest the potential for more severe toxicological effects of Se and B independently and interactively on duckling survival and development when dietary protein is diminished.
Archives of Environmental Contamination and Toxico↗
Subchronic hepatotoxicity of selenomethionine ingestion in mallard ducks
Twoyearold male mallards (Anas platyrhynchos) received a control diet (0.2 ppm Se) or diets containing 1, 2, 4, 8, 16, or 32 ppm Se as selenomethionine for 14 wk. Se accumulated readily in the liver in a dosedependent manner, reaching a mean concentration of 29 ppm (wet weight) in the 32 ppm group. Dietary Se of 2 ppm or greater increased plasma glutathione peroxidase activity. Mortality (10%) and histopathological effects, including bile duct hyperplasia and hemosiderin pigmentation of the liver and spleen, occurred in the 32 ppm group. These histopathological effects were accompanied by lower hemoglobin concentrations (16 and 32 ppm groups) and hematocrit (32 ppm group), and elevated plasma alkaline phosphatase activity (32 ppm group) indicative of cholestatic liver inJury. Other manifestations of hepatotoxicity included significant linear dose responses for hepatic oxidized glutathione (GSSG) concentrations and ratio of GSSG to reduced glutathione (GSH). Means for both of these responses differed from controls in groups receiving 832 ppm Se. Mean hepatic GSH and malondialdehyde (a measure of lipid peroxidation) concentrations were significantly elevated in the 16 and 32 ppm groups. Subchronic effects of selenomethionine, which occurs in vegetation, are of particular interest with respect to the health of wild aquatic birds in seleniferous locations.
Journal of Toxicology and Environmental Health↗
Effects of arsenate on growth and physiology in mallard ducklings
Arsenic (As) has been found at elevated concentrations in irrigation drainwater and in aquatic plants utilized by waterfowl. Mallard ( Anas platyrhynchos ) ducklings received an untreated diet (controls) or diets containing 30, 100 or 300 ppm As added as sodium arsenate. After 10 weeks blood and tissue samples were collected for biochemical and histological examination. Arsenic accumulated significantly in brain and liver of ducklings fed 100 or 300 ppm but did not result in histopathological lesions. The 300-ppm dietary As concentration decreased overall growth (weight gain) in males, whereas all concentrations of As decreased overall growth and rate of growth in females. Food consumption was less during the first three weeks in the 300-ppm group and during the second week for the 100-ppm group compared to controls. Plasma sorbitol dehydrogenase activity and plasma glucose concentration were higher in the 300-ppm group compared to controls. Plasma triglyceride concentration increased in all As-treated groups. Brain ATP was lower in the 300-ppm group and sodium/potassium-dependent ATPase activity was higher in the 30- and 100-ppm groups. Hepatic glutathione peroxidase activity was lower in the 300-ppm group and malondialdehyde lower in all treatment groups. All treatment levels caused elevation in hepatic glutathione and ATP concentrations. These findings, in combination with altered duckling behavior (increased resting time), suggest that concentrations of As that have been found in aquatic plants (up to 430 ppm dry weight) could adversely affect normal duckling development.
Environmental Toxicology and Chemistry↗
Effects of boron on growth and physiology in mallard ducklings
High concentrations of boron (B) have been associated with irrigation drainwater and aquatic plants consumed by waterfowl. Day-old mallard ( Anas platyrhynchos ) ducklings received an untreated diet (controls) or diets containing 100, 400 or 1,600 ppm B as boric acid. Survival, growth and food consumption were measured for 10 weeks. At termination, blood and tissue samples were collected for biochemical assays and histological examination. The highest dietary concentration of B caused 10% mortality, decreased overall growth and the rate of growth (sexes combined), whereas lower concentrations of B altered growth only in females. Food consumption was lower during the first 3 weeks in the 1,600-ppm group and during the second week in all B-treated groups compared to controls. Hematocrit and hemoglobin were lower and plasma calcium concentration higher in the 1,600-ppm group compared to controls. Plasma triglyceride concentration was elevated in all B-treated groups. Brain B concentration increased to 25 times that of controls in the 1,600-ppm group. Brain ATP decreased with increasing dietary B. Brain acetylcholinesterase activity and total ATPase activity (in males) were elevated and protein concentration lowered in the 1,600-ppm group. Boron accumulated less in the liver than in the brain but resulted in an initial elevation of hepatic glutathione. These findings, in combination with altered duckling behavior, suggest that concentrations of B occurring in aquatic plants could adversely affect normal duckling development.
Environmental Toxicology and Chemistry↗
Use of mixed-function oxygenases to monitor contaminant exposure in wildlife
This overview examines the utility of mixed-function oxygenase (MFO) enzymes as a bioeffects monitor for wildlife (amphibians, reptiles, birds and mammals) in view of their widespread use as indicators of contaminant exposure in aquatic invertebrates and fish. Phylogenetic trends in MFO activity, toxicological implications of induction and the relationship between contaminant exposure and MFO activity are discussed. Field studies using avian embryos and hatchlings suggest that MFO induction has utility for documenting contaminant exposure; however, findings in adult birds and mammals are equivocal. Age, sex and season are sources of variation that require consideration when undertaking field trials. Further understanding of MFO inducibility among species and application of recently developed analytical techniques including quantification of specific cytochrome P-450 isozymes are warranted.
Environmental Toxicology and Chemistry↗
Hepatic glutathione metabolism and lipid peroxidation in response to excess dietary selenomethionine and selenite in mallard ducklings
Selenium from selenomethionine accumulated in a dose-dependent manner in the liver, resulting in a decrease in hepatic-reduced glutathione with a corresponding decrease in total hepatic thiols. There was a dose-dependent increase in the oxidized to reduced glutathione ratio, and an increase in lipid peroxidation. These findings indicate that Se in the diet at 10 ppm and higher causes significant sublethal alterations in mallard ducklings, and 20-40 ppm causes significant hepatotoxicity.
Journal of Toxicology and Environmental Health↗
Effects of krenite® brush control agent (fosamine ammonium) on embryonic development in mallards and bobwhite
Fosamine ammonium (Krenite®) is a highly water-soluble carbamoylphosphonate herbicide used to control woody brush. It has been reported to be teratogenic to avian embryos following spray application of the eggs. The embryotoxic and teratogenic potential of Krenite was examined in mallards ( Anas platyrhynchos ) and bobwhite ( Colinus virginianus ). At 96 h of development, eggs were briefly immersed in distilled water or in Krenite formulation in distilled water at concentrations of 1.5, 6.5, or 30% fosamine ammonium. At 6.5% active ingredient (a.i.), Krenite reduced hatching success in bobwhite and mallards to 85 and 33% of that in the distilled-water controls. At 30% a.i., Krenite caused 95 to 100% mortality in both species by the time of hatching. Early embryonic growth was impaired by 30% Krenite in both species. There was no evidence of teratogenesis of the axial skeleton, as reported previously in chickens and Japanese quail ( Coturnix japonica ). Most abnormal embryos had severe edema and some stunting. Mallard hatchlings from the 1.5 and 6.5% Krenite groups weighed significantly less than controls and had lower plasma alanine aminotransferase and aspartate aminotransferase activities, with elevated plasma glucose and cholesterol concentrations. Brain acetylcholinesterase activity was unaffected by Krenite in embryos and hatchlings.
Environmental Toxicology and Chemistry↗
Reproduction in black-crowned night-herons fed selenium
Agricultural and industrial practices can produce wastewater that contains high concentrations of selenium, a naturally-occurring trace element. Selenium entering aquatic systems through wastewater inflow can accumulate in aquatic food chains to levels that may be toxic to fish and wildlife species. Mallard reproduction is known to be adversely affected by 10 ppm selenium in the diet (containing 7–10 percent moisture, in the form of selenomethionine); however, hatching success of eggs laid by black-crowned night-herons fed a 10 ppm selenium diet, as selenomethionine, in this study was not different from eggs laid by herons fed an unsupplemented diet (0.1 ppm selenium). Organ weights, hemoglobin concentrations, hematocrits, eggshell thickness, and shell thickness did not differ between controls and herons receiving 10 ppm selenium. Developmental malformations commonly associated with selenium exposure in other birds were not observed in heron embryos or hatchlings in the 10 ppm group. However, three-day-old hatchlings from herons fed 10 ppm selenium had shorter radius-ulna and femur lengths and higher liver malondialdehyde concentrations than controls. Selenium residues in heron eggs were lower than those reported in mallards fed the same amount of selenium. Results of this study suggest that herons are less sensitive to the toxic effects of selenium than mallards. Other hypotheses are also considered to explain the different responses of the two species.
Lake and Reservoir Management↗
Selenium toxicosis in wild aquatic birds
Severe gross and microscopic lesions and other changes were found in adult aquatic birds and in embryos from Kesterson Reservoir (a portion of Kesterson National Wildlife Refuge), Merced County, Calif., during 1984. Adult birds from that area were emaciated, had subacute to extensive chronic hepatic lesions, and had excess fluid and fibrin in the peritoneal cavity. Biochemical changes in their livers included elevated glycogen and non-protein-bound sulfhydryl concentrations and glutathione peroxidase activity but lowered protein, total sulfhydryl, and protein-bound sulfhydryl concentrations. Congenital malformations observed grossly in embryos were often multiple and included anophthalmia, microphthalmia, abnormal beaks, amelia, micromelia, ectrodactyly, and hydrocephaly. Mean concentrations of selenium in livers (94.4 ppm, dry weight) and kidneys (96.6 ppm) of birds collected at the Kesterson ponds were about 10 times those found at a nearby control area (8.3 and 12.2 ppm). We conclude that selenium present in the agricultural drainage water supplied to the Kesterson ponds accumulated in the food chain of aquatic birds to toxic concentrations and caused the lesion and other changes observed.
California↗
Embryotoxic and teratogenic effects of selenium in the diet of mallards
Mallards (Anas platyrhynchos) were fed a control diet, diets containing 1, 5, 10, or 25 ppm Se as sodium selenite, or a diet containing 10 ppm Se as seleno-DL-methionine in the first of two experiments. Selenium at 10 ppm as selenomethionine or 25 ppm as sodium selenite caused a 40-44% decrease in the total number of eggs that hatched compared to controls. Selenium at 25 ppm (sodium selenite) resulted in a 19% decrease in mean embryonic weight at 18 d of incubation, accompanied by a 6% decrease in crown-rump length. Ten parts per million Se as selenomethionine was more teratogenic than sodium selenite at 25 ppm. Selenomethionine (10 ppm Se) resulted in an incidence of 13.1% malformations that were often multiple, whereas sodium selenite (10 and 25 ppm Se) resulted in 3.6 and 4.2% malformations. The teratogenicity of selenomethionine was confirmed in a second experiment in which mallards received 1, 2, 4, 8, or 16 ppm Se as selenomethionine, resulting in 0.9, 0.5, 1.4, 6.8, and 67.9% malformations, respectively. These malformations included hydrocephaly, microphthalmia, lower bill defects, and foot defects with ectrodactyly. Both forms of selenium increased the incidence of edema and stunted embryonic growth. Selenomethionine (10 ppm Se) resulted in a significant increase of approximately 40% in plasma glutathione peroxidase activity and a 70% increase in sorbitol dehydrogenase activity (indicative of hepatotoxicity) in hatchlings. Sodium selenite (25 ppm Se) resulted in fourfold elevation in plasma uric acid concentration, indicative of renal alteration. Selenomethionine accumulated much better in eggs than did sodium selenite. These findings indicate that selenomethionine is considerably more teratogenic and generally more embryotoxic than sodium selenite, probably due to higher uptake of selenomethionine.
Journal of Toxicology and Environmental Health↗
Reproduction in mallards fed selenium
Mallards (Anas platyrhynchos) were fed diets containing 1, 5, 10, 25 or 100 ppm selenium as sodium selenite, a diet containing 10 ppm selenium as seleno-DL-methionine or a control diet. There were no effects of 1, 5 or 10 ppm selenium as sodium selenite on either weight or survival of adults or on reproductive success, and there did not appear to be a dose-response relationship at these lower levels. The 100 ppm selenium diet killed 11 of 12 adults; one adult male fed 25 ppm selenium died. Selenium at 25 and 100 ppm caused weight loss in adults. Females fed 25 ppm selenium took longer to begin laying eggs and intervals between eggs were longer than in females in other treatment groups. Hatching success appeared to be reduced in birds fed 10 ppm selenium as selenomethionine, but the reduction was not statistically significant. The survival of ducklings and the mean number of 21-d-old ducklings produced per female were reduced in the 25 ppm selenium as sodium selenite group and the 10 ppm selenium as selenomethionine group. Egg weights were not affected by any selenium treatment, but 25 ppm selenium lowered the Ratcliffe Index. Duckling weights at hatching and at 21 d of age were reduced 28 and 36%, respectively, in birds fed 25 ppm selenium, as compared with controls. Body weights measured on day 21 were lower for ducklings fed 10 ppm selenium as selenomethionine than in some other groups. Selenium in concentrations of 10 and 25 ppm as sodium selenite caused mainly embryotoxic effects, whereas 10 ppm as selenomethionine was more teratogenic, causing hydrocephaly, bill defects, eye defects (microphthalmia and anophthalmia) and foot and toe defects, including ectrodactyly. Selenomethionine was much more readily taken up by mallards and passed into their eggs than was sodium selenite, and a greater proportion of the selenium in the eggs ended up in the white when selenomethionine was fed. Adult males accumulated more selenium than did females, probably because of the females' ability to eliminate selenium in their eggs.
Environmental Toxicology and Chemistry↗
Embryonic mortality and abnormalities of aquatic birds: Apparent impacts of selenium from irrigation drainwater
Severe reproductive impacts were found in aquatic birds nesting on irrigation drainwater ponds in the San Joaquin Valley of California. Of 347 nests studied to late incubation or to hatching, 40.6% had at least one dead embryo and 19.6% had at least one embryo or chick with an obvious external anomaly. The deformities were often multiple and included missing or abnormal eyes, beaks, wings, legs and feet. Brain, heart, liver and skeletal anomalies were also present. Mean selenium concentrations in plants, invertebrates, and fish from the ponds were 22–175 ppm (dry weight), about 12 to 130 times those found at a nearby control area. Bird eggs (2.2–110 ppm) and livers (19–130 ppm) also contained elevated levels of selenium. Aquatic birds may experience similar problems in other areas where selenium occurs at elevated levels.
California↗
Lead concentrations and reproductive success in European starlings Sturnus vulgaris nesting within highway roadside verges
In 1981, the authors studied lead concentrations and reproductive success in free-living European starlings Sturnus vulgaris nesting within the verges of two Maryland highways with different traffic volumes, Route 197(average daily traffic volume[ADT] = 10,800 vehicles) and the Baltimore-Washington Parkway (ADT=52,500 vehicles) and a nearby control area. Concentrations (mg kg-1 dry weight) of lead in the ingesta (84-94 mg kg-1), carcasses (4.0-9.6 mg kg-1)and feathers (6.8-52 mg kg-1) of Parkway nestlings and adults were 3 to 13 times those found in starlings from the control area, whereas lead concentrations in the ingesta and tissues of starlings from the verge of Route 197 were similar to those of controls. Activity of delta-aminolevulinic acid dehydratase (ALAD) in red blood cells (RBCs) of adult and nestling starlings from the Parkway was depressed from 43 to 60% compared to controls. RBC ALAD activity in adults from nests along Route 197 was similar to that of adult starlings from the control area, but that of their young was depressed 17%. Haemoglobin concentrations (-16%) and haematocrits (-10%) in Parkway nestlings were depressed compared with those of nestlings from the other two study areas, whereas those of adults were not affected. Clutch size, number of young hatched and the number of young in nests 1 to 3 days before fledging were similar among sites, as were body weights of adults and prefledging weights of their young. However, brain weights of Parkway nestlings were lower (P < 0.05) than those of nestlings from the other study areas. Results suggests that lead within verges of major highways probably does not pose a serious hazard to adult ground-foraging songbirds. However, the effects of lead-induced reductions in haemoglobin concentration, haematocrit, RBC ALAD activity and brain weight on the postfledging survival of their young are not known.
Environmental Pollution (Series A)↗
Association between PCBs and lower embryonic weight in black-crowned night herons in San Francisco Bay
Reproductive problems, including congenital malformations, reduced hatching success, and decreased survival of hatchlings, have been observed in colonial-nesting water birds at the San Francisco Bay National Wildlife Refuge (SFBNWR). Twenty-four black-crowned night heron (Nycticorax nycticorax) eggs were collected from SFBNWR in 1983. Twelve of these were collected from separate nests when late-stage embryos were pipping, and an additional egg was randomly collected from each nest for organochlorine analysis. Overt anomalies and skeletal defects were not apparent. Embryonic weights (with partially absorbed yolk sacs removed) were 15% lower (p lt 0.05) in SFBNWR embryos compared to control embryos from the Patuxent Wildlife Research Center (PWRC). Crown-rump length and femur length were shorter for SFBNWR embryos. The geometric mean polychlorinated biphenyl (PCB) concentration in SFBNWR eggs was 4.1 ppm wet weight, with a range of 0.8-52.0 ppm. A negative correlation (r = - 0.61; p lt 0.05) existed between embryonic weight and log-transformed PCB residues in whole eggs collected from the same nest at SFBNWR, suggesting a possible impact of PCBs on embryonic growth. A correlation with embryonic weight did not occur for DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) residues. Liver microsomal aryl hydrocarbon hydroxylase activity was neither significantly elevated nor correlated with PCB, DDE, or PCB plus DDE log-transformed residues. It is unknown whether the apparent association between PCBs and lower weight is persistent through hatching.
Journal of Toxicology and Environmental Health↗