Rapid coastal survey of anthropogenic radionuclides, metals, and organic compounds in surficial marine sediments.

A towed survey system, the GIMS/CS3, has been developed to enable the rapid measurement and mapping of a variety of physical and geochemical parameters in the surficial sediments of aquatic environments while the survey vessel is underway. With its capability for measuring radiometric, elemental and organic compound constituents of sediments, as well as bathymetry and water quality parameters, the GIMS/CS3 provides a cost-effective means of performing reconnaissance determinations of contaminant distributions and environmental monitoring tasks over broad geographic regions.

Sublethal concentrations of mercury in river otters: monitoring environmental contamination.

Hair, muscle, and liver mercury concentrations were determined in river otter (Lutra canadensis) carcasses collected from the lower coastal plain and piedmont of Georgia. Mean muscle and hair mercury concentrations were greater (P < 0.001) in otters from the lower coastal plain (4.42 and 24.25 mg/kg wet wt, respectively) compared to otters from the piedmont (1.48 and 15.24 mg/kg, respectively). Liver tissue from lower coastal plain otters averaged 7.53 mg/kg mercury. Mean fetus brain and muscle mercury concentrations were 1.03 and 1.58 mg/kg wet wt, respectively, and fetal muscle mercury concentrations were correlated (r = 0.92) with maternal muscle mercury concentrations. Comparison of mercury concentrations found in Georgia otters to those associated with adverse effects in otter and mink (Mustela vison), indicate sublethal contamination with concentrations in some individuals approaching that observed in experimentally dosed individuals that developed clinical signs of mercurialism. Mercury concentrations in fish from the lower coastal plain approached or exceeded concentrations demonstrated to be toxic to experimentally dosed otters.

Severe pododermatitis in broiler breeder hens housed on pressure-treated slats.

Severe foot-pad dermatitis was diagnosed in a case of broiler hens housed on slats made of lumber pressure-treated with chromated copper arsenate. Studies were conducted in an attempt to determine whether contact with the lumber caused the lesions. Breeder pullets were housed for 17 weeks on slats made from either untreated oak or pressure-treated lumber. Cresylic acid disinfectant was applied to one set of each slat type. Foot-pad lesions were scored and tissue arsenic levels were measured. Foot pads of the hens on pressure-treated slats were the only tissue with detectable arsenic levels. All groups developed foot-pad lesions, although the lesions appeared to be most severe, and to have developed earlier, in birds on pressure-treated disinfected slats.

Forest worker exposure to airborne herbicide residues in smoke from prescribed fires in the southern United States.

Occupational safety and health concerns have been raised in a number of southern states by workers conducting prescribed burns on forest lands treated with herbicides. Modeling assessments coupled with laboratory experiments have shown that the risk of airborne herbicide residues to workers is insignificant, even if the fire occurs immediately after herbicide application. However, no field studies had been conducted to confirm these findings. To bridge that gap, a field validation study was conducted in Georgia to measure breathing zone concentrations of smoke suspended particulate matter (SPM), herbicide residues, and carbon monoxide (CO) on 14 operational prescribed fires. Smoke was monitored on sites treated with labeled rates of forestry herbicides containing the active ingredients imazapyr, triclopyr, hexazinone, and picloram. The sites were burned within 30-169 days after herbicide application. Tract size ranged from 2.4 to 154 hectares. Personal monitors and area monitors employing glass fiber filters and polyurethane foam collection media were used. No herbicide residues were detected in the 140 smoke samples from the 14 fires conducted in this study. The sensitivity of the monitoring methods was in the 0.1 to 4.0 micrograms/m3 range, which is several hundred to several thousand times less than any established occupational exposure limit for herbicides. The SPM and CO monitored on these fires is the first time breathing zone concentrations of these smoke constituents have been measured in the South. As expected, concentrations were highly variable depending on fire conditions and the location of personnel. Worker respirable (2.3-microns particle cut point) SPM concentrations ranged between 0.2 and 3.7 mg/m3.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute toxicity of boric acid and boron tissue residues after chronic exposure in broiler chickens.

The acute oral mean lethal dose of boric acid in 1-day-old chickens was found to be 2.95 +/- 0.35 g/kg of body weight, which classifies this product as only slightly toxic to chickens. One-day-old broiler chicks were housed in floor pens in which litter had been treated with 0, 0.9, 3.6, or 7.2 kg of boric acid per 9.9 m2 of floor space. Boron residue levels in brain, kidney, liver, and white muscle were not statistically elevated following a 15-day exposure period. Boron residue levels in the same types of tissue were not significantly elevated in chicks fed 500 ppm or 1250 ppm boric acid in feed ad libitum for 3 weeks; however, residues were significantly higher in chicks fed 2500 ppm or 5000 ppm boric acid. These data indicate that broilers grown on boric acid-treated litter do not consume enough boric acid to cause elevated boron levels in tissues.

Effects of the insecticides carbofuran and fenvalerate on adenylate parameters in bluegill sunfish (Lepomis macrochirus).

Bluegills (Lepomis macrochirus) were exposed to two sublethal concentrations of carbofuran, a carbamate insecticide, and fenvalerate, a synthetic pyrethroid insecticide, in continuous flow bioassay systems for 30 days. Adenylate parameters (ATP concentration, total adenylates concentration, and adenylate energy charge) were monitored in gill, liver, muscle, and stomach tissues. There were significant decreases in adenylate energy charge of gill and stomach tissue relative to initial values after 10 days of exposure to 30 micrograms/L carbofuran. There was also a significant decline in adenylate energy charge in gills of fish exposed to 0.2 micrograms/L fenvalerate relative to initial values. These values returned to normal by the end of the experiment. The biological significance of these changes is uncertain. Adenylate parameters may not be sufficiently sensitive to reflect sublethal effects of pesticides which affect the nervous system of fishes.

Case histories of wild birds killed intentionally with famphur in Georgia and West Virginia.

Five incidences of bird mortality in Georgia and West Virginia (USA) involving migratory waterfowl, cranes, raptors, corvids and songbirds were investigated during the first 6 mo of 1988. Gross and histopathologic examinations revealed no evidence of infectious or other diseases. However, severe depression of cholinesterase activity was evident in brains of birds found dead, suggesting gross exposure to an organophosphorus (OP) or carbamate pesticide. All of the gastrointestinal tract contents chemically analyzed contained famphur, an OP insecticide used as a pour-on treatment against lice and grubs on livestock, ranging from 5 to 1,480 ppm (wet weight). Grain scattered at two of the mortality sites contained 4,240 and 8,500 ppm famphur. Gastrointestinal tracts of most of the dead birds contained mainly corn and some wheat. This is the first report to document the use of famphur as an intentional means of killing wildlife thought to be depredating crops.

Modulation of immune responses in mice by d-limonene.

The immunotoxicologic effects of d-limonene were determined. This naturally occurring substance is widely used in food flavorings and is a common additive in cosmetics. In the present study, BALB/c mice were treated with d-limonene for 9 wk. Effects on T- and B-cell responses were determined after 4 and 8 wk of treatment. Concanavalin-A responses at 8 wk, but not 4 wk, were suppressed in treated mice. A similar trend was observed for phytohemagglutinin and lipopolysaccharide responses. Evidence was presented that d-limonene had polyclonal activator action. Mice primed with keyhole limpet hemocyanin (KLH) prior to initiation of d-limonene treatment had suppressed primary and secondary anti-KLH responses. Mice treated with d-limonene prior to KLH priming produced significant increased antibody responses. Additional evidence for polyclonal stimulation was obtained by histopathologic examination of secondary lymphoreticular tissue. Significant secondary follicle development and prominent lymphoid nodules and aggregates were found in the pancreas and intestinal mucosa, particularly apparent in mice receiving the highest d-limonene dosage. A subchronic LD50 study was conducted wherein BALB/c mice received 16 daily doses of d-limonene. An LD50 of approximately 0.0850 mg d-limonene/kg (corrected for 82% purity) was determined.

PCB intake and the growth of waterfowl: multivariate analyses based on a reparameterized Richards sigmoid model.

Multivariate analyses of the parameters of a modified Richards growth model were used to determine the effects of sex and varying levels of dietary intake of PCB's (0-50 ppm), on the asymptotic size (W infinity), total growing time (T) and shape (m) of the growth curves of game farm mallards (Anas platyrhynchos) and wild wood ducks (Aix sponsa) raised under laboratory conditions. Level of PCB intake did not affect any of the growth parameters of the wood ducks, while sex affected both m and W infinity, with males of this species growing to greater body weights and showing slightly lower shape parameters than females. Growth characteristics of the mallards on the other hand, did not differ between the sexes. PCB intake however, had a significant effect on the shape of the mallard growth curve, but did not affect either W infinity or T. All interactions between sex and PCB treatment level were non-significant in both species. The growth responses of game-farm mallards to PCB intake cannot be assumed to typify that of other wild waterfowl species without additional evidence from comparative studies.

Sigmoid growth analyses of wood ducks: the effects of sex, dietary protein and cadmium on parameters of the Richards model.

Growth analyses were conducted for 194 captive-reared wood ducks, using a reparameterized Richards process error model which provided estimates of: asymptotic size (W infinity); an approximation of the amount of time required to complete the growing period (T); and the Richards shape parameter (m). Multivariate analysis of variance indicated that growth was affected by sex and the level of cadmium in the diet on which the birds were reared (0-100 ppm). Crude protein in the diet (high = 30%; low = 18%) did not affect growth. Univariate analyses indicated that the growth of the sexes differed only with respect to W infinity, with males growing to larger body weights than females. Cadmium, however, altered both T and m, with longer times being required to complete growth in both controls which received no cadmium, and at higher levels of cadmium intake. Intermediate treatment levels completed growth in the shortest periods of time. Increasing cadmium intake altered the shape of the growth curve by progressively delaying the time at which maximum growth rate occurred.

Pharmacokinetics of 4-aminopyridine in cattle.

Concentrations of 4-aminopyridine hydrochloride in plasma of cattle were measured over an 8-hour period following a bolus IV injection (0.3 mg/kg). The drug was assayed by a gas-liquid chromatographic method using a nitrogen-phosphorus detector. Plasma 4-aminopyridine hydrochloride vs time data best fit a 2-compartment pharmacokinetic model. Distribution half-life was 12.08 minutes; elimination half-life, 128.96 minutes; volume of the central compartment, 1.48 L/kg; volume of distribution based on total area, 3.07 L/kg; volume of distribution at steady state, 2.75 L/kg; and body clearance, 16.57 ml/min/kg.

Pharmacokinetics of 4-aminopyridine in horses.

The pharmacokinetics of 4-aminopyridine (4-AP), a drug capable of antagonizing nondepolarizing neuromuscular blocking drugs, as well as several classes of injectable sedative and anesthetic agents, were studied in 6 intact, awake horses. Plasma samples were assayed for 4-AP over a frequent sampling schedule for 8 hours after IV administration. The plasma 4-AP vs time data best fit a 2-compartment pharmacokinetic model. Distribution half-life was 7.4 minutes, elimination half-life was 259 minutes, volume of the central compartment was 0.89 L/kg, volume of distribution (area) was 1.98 L/kg, volume of distribution at steady state was 1.9 L/kg, and total clearance was 5.3 ml min(-1) kg(-1). The 259-minute elimination halflife observed in the present study is consistent with prolonged clinical effectiveness observed in a previous study of antagonism of xylazine/ketamine anesthesia by 4-AP in horses.

Impact of hexazinone on invertebrates after application to forested watersheds.

The impact of the herbicide, hexazinone, was assessed on aquatic macrophytes, aquatic and terrestrial invertebrate communities within forested watersheds in the Piedmont region of Georgia. Four replicate watersheds received hexazinone on April 23, 1979, and were subsequently monitored for eight months. Residue levels in terrestrial invertebrates were a maximum of two orders of magnitude greater than comparable levels (0.01 to 0.18 ppm) found in forest floor material. Aquatic organisms in a second order perennial stream were exposed to intermittent concentrations of hexazinone (6 to 44 ppb). Hexazinone and its metabolites were generally not detected (less than 0.1 ppm) in aquatic invertebrates and macrophytes. No major alterations in species composition or diversity were detected in the aquatic macroinvertebrate community. Terrestrial microarthropod samples collected near the end of the study period revealed no major community changes.

Tissue residues of dietary cadmium in wood ducks.

One-week-old wood ducks were fed cadmium in diets containing 18 or 30% protein for a period of three months. Seven drakes from each group were sacrificed, and blood, brain, muscle, kidney, liver, and wing feather tissues were collected and analyzed for cadmium. Highest cadmium concentrations were found in the kidney, liver, and feather tissues; blood, muscle, and brain cadmium residue levels were undetectable. Except in the kidney tissue, protein level of the diet did not affect cadmium residue levels. For birds that were changed to a cadmium-free, high-protein ration at 13 weeks of age, regression analysis indicated a significant decrease in cadmium residue levels for the kidney tissue only. Growth, as measured by bodyweight at 13 weeks of age, was not affected by the various cadmium treatment levels. Histopathological examination revealed lesions in the kidney tissues of the 100 ppm cadmium treatment groups, which were more severe in those birds receiving the 18% protein diet. Vacuolation of the pancreatic acinar cells was observed in all groups, but tended to occur more frequently in the higher cadmium level groups.

Toxicity and bioaccumulation of pentachlorophenol in broiler chickens.

Hubbard-Hubbard broiler chickens were fed graded levels (0, 1, 10, 100, and 1000 ppm) of pentachlorophenol (PCP) containing less than .0023% octachlorodibenzo-p-dioxin (OCDD) for 8 weeks. Tissue samples for PCP, OCDD, and pentachloroanisole (PCA) were cleaned up via gel permeation chromatography and analyzed by gas chromatography employing electron capture detection. Kidney weights were significantly increased by the 100 ppm and 1000 ppm PCP diet. Weights of all other organs including the body weights were significantly lowered by the 1000 ppm PCP diet. Except for the control group, histopathologic examination of the liver revealed bile duct proliferation and some fatty changes in all of the 6-week-old birds. Examination of the brain, liver, gizzard, pancreas, intestine, proventriculus, spleen, kidney, lung, and heart revealed no histopathological lesions in the treated or control birds. Significant linear relationships were found between PCP accumulation in tissues and the concentration of dietary PCP. Accumulation of PCP was greatest in the kidney followed by liver, heart, leg, breast, gizzard, and fat. The high residue levels in the kidney and liver may reflect principal routes of elimination and metabolism. Following a 5 week withdrawal of PCP from the diet, PCP residues were still present in the adipose tissue of all treated birds. Residue levels in the kidney and liver were reduced at the first and third week of withdrawal, but a continuous decline was interrupted by a slight elevation in residue level at the fifth week of withdrawal from the chemical.