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At least 181 records · Page 10Linked to original sources
USGS2011

MercNet: A national monitoring network to assess responses to changing mercury emissions in the United States

A partnership of federal and state agencies, tribes, industry, and scientists from academic research and environmental organizations is establishing a national, policy-relevant mercury monitoring network, called MercNet, to address key questions concerning changes in anthropogenic mercury emissions and deposition, associated linkages to ecosystem effects, and recovery from mercury contamination. This network would quantify mercury in the atmosphere, land, water, and biota in terrestrial, freshwater, and coastal ecosystems to provide a national scientific capability for evaluating the benefits and effectiveness of emission controls. Program development began with two workshops, convened to establish network goals, to select key indicators for monitoring, to propose a geographic network of monitoring sites, and to design a monitoring plan. MercNet relies strongly on multi-institutional partnerships to secure the capabilities and comprehensive data that are needed to develop, calibrate, and refine predictive mercury models and to guide effective management. Ongoing collaborative efforts include the: (1) development of regional multi-media databases on mercury in the Laurentian Great Lakes, northeastern United States, and eastern Canada; (2) syntheses and reporting of these data for the scientific and policy communities; and (3) evaluation of potential monitoring sites. The MercNet approach could be applied to the development of other monitoring programs, such as emerging efforts to monitor and assess global mercury emission controls.

Ecotoxicology↗
USGS1976

Delta-aminolevulinic acid dehydratase: Inhibition in ducks dosed with lead shot

Lead concentration in blood and erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity was measured in mallard ducks dosed with one all-lead shot or one lead-iron combination shot. For 2 weeks after dosage, lead in blood of ducks given an all-lead shot was fourfold higher than in those dosed with lead-iron shot. At 3 and 4 weeks, the differences in lead residues were directly proportional to lead content of the shots. ALAD activities measured at these intervals were inversely correlated (P < 0.01) with the concentration of lead in the blood, suggesting that biochemical responses to the two types of shot were dependent upon the quantity of lead present.

Environmental Research↗
USGS1978

Effects of chronic ingestion of South Louisiana crude oil on mallard ducklings

South Louisiana crude oil was fed to duckling mallards (Anas platyrhynchos) in concentrations of 0.025, 0.25, 2.5, and 5.0% of the diet from hatching to 8 weeks of age to assess the effects of chronic oil ingestion during early development. Growth was depressed in birds receiving a diet containing 5% oil but there was no oil-related mortality. Diets containing 0.25, 2.5, and 5.0% oil impaired avoidance behavior of 6-day-old mallard ducklings when compared with controls or ducklings fed 0.025% oil, but had no effect on open-field behavior of 7-day-old ducklings. Liver hypertrophy and splenic atrophy were gross evidence of the pathological effects of oil in birds on the 2.5 and 5.0% oil diets. Biochemical lesions that occurred included elevation of plasma alanine aminotransferase and ornithine carbamyl transferase activity. Hepatocyte hypertrophy and bile duct proliferation in the liver were noted in birds fed the 2.5 and 5.0% oil diets and tubular inflammation and degeneration in the kidney were noted in birds fed the 5.0% oil diet.

Environmental Research↗
USGS1978

Uptake and retention of dietary cadmium in mallard ducks

Adult mallard ducks fed 0, 2, 20, or 200 ppm of cadmium chloride in the diet were sacrificed at 30-day intervals and tissues were analyzed for cadmium. No birds died during the study and body weights did not change. The liver and kidney accumulated the highest levels of cadmium. Tissue residues were significantly correlated in all treatment groups and residues increased with treatment level. Hematocrits and hemoglobin concentrations were normal in all groups throughout the study. Little cadmium accumulated in eggs of laying hens, but egg production was suppressed in the group fed 200 ppm.

Environmental Research↗
USGS1979

Delta-aminolevulinic acid dehydratase enzyme activity in blood, brain, and liver of lead-dosed ducks

Mallard ducks were dosed with a single shotgun pellet (ca. 200 mg lead). After 1 month there was about 1 ppm lead in blood, 2.5 in liver, and 0.5 in brain. Lead-induced inhibition of delta-aminolevulinic acid dehydratase enzyme in blood and cerebellum was much greater than in cerebral hemisphere or liver and was strongly correlated with the lead concentration in these tissues. The cerebellar portion of the brain was more sensitive to delta-aminolevulinic acid dehydratase enzyme inhibition by lead than were the other tissues examined. There was also a greater increase in the glial cell marker enzyme, butyrylcholinesterase, in cerebellum than in cerebral hemisphere, suggesting that nonregenerating neuronal cells were destroyed by lead and replaced by glial cells in that portion of the brain. Even partial loss of cerebellar tissue is severely debilitating in waterfowl, because functions critical to survival such as visual, auditory, motor, and reflex responses are integrated at this brain center.

Environmental Research↗
USGS1980

Aroclor 1242 and reproductive success of adult mallards (Anas platyrhynchos)

Twenty-four pairs of adult mallards were fed a diet containing 0 or 150 ppm of the PCB Aroclor 1242 for 12 weeks during which egg laying was induced. Laying started in both groups an average of 33 days after PCB treatment began. All hens were allowed to lay a 20-egg clutch; 15 eggs from each clutch were artificially incubated. Eleven hens from each group completed the clutch. There was no difference between the two groups in the time taken to lay the clutch, nor was there a difference in fertility, embryo mortality, or hatching success. Eggshell thickness decreased 8.9% with PCB ingestion; eggs from hens fed PCB contained an average of 105 ppm PCB wet wt. No difference in survival or weight gain to 3 weeks of age was observed between young mallards from eggs laid by PCB-treated hens and control hens.

Environmental Research↗
USGS1980

Transfer of crude oil from contaminated water to bird eggs

Paris of breeding mallard ducks were exposed to oiled water for 2 days during the first week of incubation. Hatching success of ducks exposed to 100 ml of Prudhoe Bay crude oil per square meter of water surface was significantly less than that of controls. Hatching success of ducks exposed to 5 ml of crude oil per square meter of water surface was less than that of controls but the difference was not significant. The presence of oil on the eggs of ducks exposed to oiled water was confirmed by chemical analysis. Thermocouple probes were used to monitor the egg and nest temperatures of some of the ducks in each of the three groups. Incubation temperatures of oiled females were not significantly different from those of the controls. The incubation behavior of females exposed to oiled water and the first-week survival of their ducklings was not affected by the oil.

Environmental Research↗
USGS1981

Response of adult mallard ducks to ingested South Louisiana crude oil

Adult mallards ( Anas platyrhynchos ) were fed South Louisiana crude oil as 0.25 and 2.5% of the total diet for 26 weeks to assess the chronic effects of oil ingestion. Additional birds were fed diets containing either 1.0% of a paraffin mixture or clean feed. No birds died during the study, nor were their body weights significantly depressed. Oviduct weight at necropsy was greatly reduced in hens on the 2.5% oil diet and also was significantly reduced in hens on the 0.25% oil diet when compared with controls. Male reproductive organs were not atrophied by treatment. Hens on oil-treated diets laid fewer eggs than those on the control diet; however, eggs from treated hens hatched as well as those from controls when artificially incubated. Pathological or biochemical alterations were no greater in the treated birds than in controls.

Environmental Research↗
USGS1981

The effects of ingested petroleum on the maphthalene-metabolizing properties of the liver tissue in seawater-adapted mallard ducks (Anas platyrhynchos)

Hepatic mixed function oxidase activities were estimated in seawater-adapted mallard ducks (Anas platyrhynchos) that had been consuming food contaminated with one of five different types of crude oil. After 50 days of exposure to contaminated food, enzyme activities of liver microsomal preparations were assessed in terms of their naphthalenemetabolizing properties in vitro. Although dose-dependent increases in the total hepatic enzyme activities (nmole naphthalene metabolized per minute per unit mass body weight) were observed in birds consuming food contaminated with each type of crude oil, three patterns of response were apparent. Crude oils from South Louisiana and Kuwait stimulated large and significant increases in the specific activity of the enzyme system (nmole naphthalene metabolized per minute per unit mass microsomal protein), whereas little or no increase in either microsomal protein content or relative liver weight were observed. In contrast, two crude oils from Santa Barbara, Calif., induced only small increases in specific activity but significant increases occurred in hepatic microsomal protein concentration and relative liver weight. The crude oil from Prudhoe Bay, Ala., evoked intermediate patterns of response. The possible significance of these data is discussed in relation to the survival of seabirds consuming petroleum-contaminated food and drinking water.

Environmental Research↗
USGS1981

Effects of malathion, diazinon, and parathion on mallard embryo development and cholinesterase activity

The effects of external exposure of mallard ( Anas platyrhynchos ) eggs to malathion, diazinon, and parathion were examined using formulations and concentrations similar to field applications. Treatment with aqueous emulsion simulated exposure at the rate of 100 gal per acre (153 liters/hectare) with three to six different doses per compound with treatment at 3 and 8 days of embryonic development. Treatment with a nontoxic oil vehicle simulated exposure at the rate of 11 gal per acre (16.8 liters/hectare) with three to six different doses per compound. The order of embryotoxicity on a pounds-per-acre basis was parathion > diazinon > malathion with either vehicle. However, the potential hazard under conditions of up to five times the maximum field level of application was greater for malathion because of the high permissible level of application for malathion on certain crops. Parathion, the most embryotoxic of the three, had the most pronounced effects when an oil vehicle was used, as reflected by an LC 50 of about 2 lb of active ingredient per acre, stunted growth, and a high frequency of malformations involving distortion of the axial skeleton, particularly in the cervical region. All three compounds resulted in significant depression of plasma and brain cholinesterase activity, but parathion caused the most depression throughout development, which was still apparent in hatchlings. Treatment with either distilled water or oil vehicle alone did not result in any of these effects seen with organophosphorous insecticides.

Environmental Research↗
USGS1983

Effects of dietary cadmium on mallard ducklings

Mallard (Anas platyrhynchos) ducklings were fed cadmium in the diet at 0, 5, 10, or 20 ppm from 1 day of age until 12 weeks of age. At 4-week intervals six males and six females from each dietary group were randomly selected, bled by jugular venipuncture, and necropsied. Significant decreases in packed cell volume (PCV) and hemoglobin (Hb) concentration and a significant increase in serum glutamic pyruvic transaminase (GPT) were found at 8 weeks of age in ducklings fed 20 ppm cadmium. Mild to severe kidney lesions were evident in ducklings fed 20 ppm cadmium for 12 weeks. No other blood chemistry measurement, hematological parameter, or tissue histopathological measurement indicated a reaction to cadmium ingestion. Body weight, liver weight, and the ratio of the femur weight to length were not affected by dietary cadmium. Femur cadmium concentration In all ducklings 12 weeks of age declined from the values detected at 4 and 8 weeks of age. Liver cadmium concentrations were significantly higher in relation to the increased dietary levels and in relation to the length of time the ducklings were fed the cadmium diets. At 12 weeks of age the cadmium concentration in liver tissue was twice that in the diet.

Environmental Research↗
USGS1983

FLIT-MLO and No. 2 fuel oil: Effects of aerosol applications to mallard eggs on hatchability and behavior of ducklings

FLIT-MLO and No. 2 fuel oil are sprayed on wetlands for mosquito control during spring and summer. In one experiment to assess the effects of the spraying on birds, mallard eggs were sprayed with amounts of No. 2 fuel oil equivalent to 2.34, 4.67, or 18.70 liters/ha or FLIT-MLO equivalent to 9.35, 46.75, or 140.25 liters/ha on Day 6 of incubation. In a second experiment, mallard eggs were sprayed with 9.35, 46.75, or 140.25 liters/ha of FLIT-MLO on Days 3, 6, 12, or 18 of incubation. Hatchability of eggs sprayed with the highest treatment level of each substance was significantly lower than that of controls for the first experiment. Hatchability of eggs sprayed with FLIT-MLO in the second experiment was never significantly lower than that of controls. Ducklings from the first experiment, 36-48 hr old, were cold stressed for 1 hr at 8 degrees C and then immediately tested for their ability to respond to a fright stimulus. Ducklings from the group of eggs sprayed with 140.25 liters/ha of FLIT-MLO ran a significantly shorter distance from the fright stimulus than did controls. The effects of the heaviest exposure to FLIT-MLO (140.25 liters/ha) on egg hatchability and behavior of newly hatched young are uncertain because of the contradictory results for hatching success in the two experiments. However, normal applications of FLIT-MLO (9.35-46.75 liters/ha) or No. 2 fuel oil (2.34-4.67 liters/ha) do not appear to pose a threat to the embryos of breeding birds.

Environmental Research↗
USGS1984

Sensitivity of nestling and adult starlings to dicrotophos, an organophosphate pesticide

The 24-hr median lethal dose (LD50) of dicrotophos (3-hydroxy-N,N-dimethyl-cis-crotonamide dimethyl phosphate) for free-living 5-day-old nestling European starlings (Sturnus vulgaris, LDso = 4.92 mg/kg body wt) was about one-half that obtained for free-living 15day-old nestlings (9.59 mg/kg) and captive adult males (8.37 mg/kg) and females (8.47 mg/ kg). Nestlings and adults with low pretreatment body weights appeared to be more vulnerable to organophosphate (OP) exposure. Brain cholinesterase (ChE) activity was severely depressed in all birds that died (74-94%); the degree of inhibition did not vary with age or sex. Inhibition of brain ChE in 5-day-old nestlings alive 24 hr post dose (X = 28-43%) was lower than that of 15-day-old (X = 55-68%) and adult (X = 55-77%) survivors. Body weights of OP-dosed birds that died were depressed an average of 20 to 46% in 5-day-olds, 7 to 20% in 15-day-olds, and 0 to 10% in adults; weight losses varied inversely with age and dosage, and directly with time to death. Average weight losses in 5- and 15-day-old survivors (X < 31 and 26%, respectively) varied directly with dose and exceeded comparable values for adults (X = 3-15%). Results suggest that (1) young nestling songbirds may be nearly twice as sensitive as adults to OPs, (2) growth of nestlings may be severely depressed following OP exposure, and (3) recovery of brain ChE activity following exposure to ChE inhibitors may be more rapid in nestlings than adults.

Environmental Research↗
USGS1989

Impacts of exploratory drilling for oil and gas on the benthic environment of Georges Bank

A 3-year monitoring program was performed to assess the impacts of exploratory drilling for oil and gas on the benthic environment of Georges Bank, an important commercial fishery region in the North Atlantic east of Massachusetts, USA. Surficial sediments were sampled for chemical and benthic infaunal analysis and bottom still photographs were taken to document bottom microtopography and epifauna at 46 stations during 12 field surveys. The surveys were performed quarterly from just before drilling began, during drilling, and for nearly 2 years after completion of drilling. Two of the eight drilling sites were selected for monitoring. Twenty-nine stations were positioned in a tight radial array around a drilling site in 80 m of water. A second group of three stations was positioned near another drilling site in 140 m of water. The remaining stations covered a broad expanse of the Bank and adjacent suspected sites of deposition of fine-grained sediments.\ Of the 12 elements analyzed in bulk sediments, only barium increased in concentration during the period when drilling was taking place (July 1981 to September 1982). The concentration of barium in surficial sediment increased 4&middot;7-fold from 28 ppm before drilling to 131&middot;7 ppm after drilling at the station closest to the drilling site in 80 m of water and 5&middot;9-fold from 32 ppm before drilling to 172 ppm after drilling at the station closest to the drilling site in 140 m of water. The concentrations of both barium and chromium increased in the fine (silt/clay) fraction (usually less than 5% by weight of sediment from most stations) of sediments from several stations around one or both rig sites monitored during the period of drilling. Elevated concentrations of chromium (about two-fold) occurred only in sediments near the drilling site in 140 m of water. Statistically significant increases in the concentration of barium in the fine fraction to sediment were detected approximately 65 km west (downcurrent) and 35 km east of the drilling site in 80 m of water after drilling was completed. The benthic fauna were abundant and diverse throughout the study area. At most stations, the dominant species remained nearly the same from one season to another over the 3 years of sampling. Polychaetes were the most abundant, followed by crustaceans. The number of individuals of some species, particularly the amphipods Erichthonius fasciatus and Unciola inermis , showed large seasonal variations. Cluster analysis revealed a strong relationship between community structure and both sediment type and water depth. Little seasonal variation was detected, but some interannual differences were revealed by cluster analysis and correspondence analysis. The replicates from a station always resembled each other more than they resembled any replicates from other stations. In addition, the combined replicates from a station always clustered with samples from that station taken on other cruises. This excellent replication and uniformity of the benthic infaunal community at a station over time made it possible to detect very subtle changes in community parameters that might be related to discharges of drilling fluid and drill cuttings. Nevertheless, no changes were detected in benthic communities of Georges Bank that could be attributed to drilling activities.

Massachusetts↗
USGS1996

Distributions and fate of chlorinated pesticides, biomarkers and polycyclic aromatic hydrocarbons in sediments along a contamination gradient from a point-source in San Francisco Bay, California

The distribution and fate of chlorinated pesticides, biomarkers, and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments along a contamination gradient in the Lauritzen Canal and Richmond Harbor in San Francisco Bay was investigated. Compounds were identified and quantified using gas chromatography-ion trap mass spectrometry. Biomarkers and PAHs were derived primarily from weathered petroleum. DDT was reductively dechlorinated under anoxic conditions to DDD and several minor degradation products, DDMU, DDMS, and DDNU. Under aerobic conditions, DDT was dehydrochlorinated to DDE and DBP. Aerobic degradation of DDT was diminished or inhibited in zones of high concentration, and increased significantly in zones of lower concentration: Other chlorinated pesticides identified in sediment included dieldrin and chlordane isomers. Multivariate analysis of the distributions of the DDTs suggested that there are probably two sources of DDD. In addition, DDE and DDMU are probably formed by similar mechanisms, i.e. dehydrochlorination. A steep concentration gradient existed from the Canal to the Outer Richmond Harbor, but higher levels of DDD than those found in the remainder of the Bay indicated that these contaminants are transported on particulates and colloidal organic matter from this source into San Francisco Bay. Chlorinated pesticides and PAHs may pose a potential problem to biota in San Francisco Bay.

Marine Environmental Research↗
USGS1996

Rainbow trout embryotoxicity of a complex contaminant mixture extracted from Lake Michigan lake trout

Persistent Hydrophobic contaminants such as poly chlorinated dibenzo- p -dioxins, dibenzofurans and biphenyl congeners are present in aquatic systems, and are known to produce adverse effects in fish. Reproductive failure in fish populations has been observed in aquatic systems contaminated with persistent hydrophobic compounds. In order to mimic maternal transfer of environmental contaminants to newly fertilized fish eggs, a complex environmental extract was tested for embryotoxicity in a nanoinjection bioassay with embryos of rainbow trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The tissue extraction involved blending and dehydration with sodium sulfate, column extraction, dialysis separation, reactive cleanup and, finally, high-performance gel permeation chromatography. Egg gram-equivalent doses (g tissue/g egg normalized for egg % lipid) of the final extract (0.02, 0.10, 0.20, 1.0, 2.0, 4.0, 10.0, 20.0 eggEQ) were injected into newly fertilized rainbow trout eggs using triolein as the vehicle. The extract of the lake trout was embryotoxic to rainbow trout, with an LD 50 of 35 eggEQ, based on total cumulative mortality. Gross physical abnormalities characteristic of dioxin exposure, such as hemorrhaging, yolk-sac edema and craniofacial deformities, were observed and showed significant dose-related increases. Sublethal effects in the rainbow trout, such as delayed time to hatch, mild hemorrhaging and moderate yolk-sac edema, resulted from estimated total PCB exposure as low as 8.8 ng/g, and this may have significant implications on Great Lakes lake trout fry and juvenile mortality.

Marine Environmental Research↗
USGS2007

Suspended sediment and sediment-associated contaminants in San Francisco Bay

Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transporthas improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls.

Environmental Research↗