SEARCH · USGS Science

Results for “Toxics”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources

USGS2021

Lampricide bioavailability and toxicity to invasive sea lamprey and non-target fishes: The importance of alkalinity, pH, and the gill microenvironment

The lampricides TFM and niclosamide are added to streams to control invasive larval sea lamprey ( Petromyzon marinus ) populations in the Laurentian Great Lakes. Lampricide effectiveness depends upon TFM and niclosamide bioavailability which is influenced by both abiotic and biotic factors. For example, at lower pH, TFM bioavailability is higher because a greater proportion exists as un-ionized TFM (TFM-OH), which easily crosses the gills. At higher pH, however, the negatively charged ionized species of TFM (TFM-O − ) predominates, which is less easily taken-up, meaning more TFM must be applied. Although water alkalinity does not directly affect TFM speciation, as a buffer it influences how much expired water crossing the gills is acidified by CO 2 and metabolic acid excretion. In poorly buffered waters, greater acidification of the expired water increases TFM bioavailability in the gill microenvironment than in better buffered, higher alkalinity waters where more TFM must be applied. Hence, sea lamprey and non-target fishes such as lake sturgeon ( Acipenser fulvescens ) are more sensitive to lampricides in low pH, low alkalinity waters. Differences in gill structure and microenvironment acidification might also explain why TFM sensitivity of young-of-the-year lake sturgeon approaches or exceeds that of sea lamprey in higher alkalinity waters. Other biotic factors such as body size and metabolic rate also contribute to differences in lampricide sensitivity. We conclude that better understanding of the abiotic and biotic factors influencing lampricide bioavailability can be used to refine treatment protocols to improve lampricide effectiveness and to better protect non-target fishes from lampricide toxicity.

Journal of Great Lakes Research↗

USGS2020

Legacy and current-use toxic contaminants in Pacific sand lance (Ammodytes personatus) from Puget Sound, Washington

Forage fish are primary prey for seabirds, fish and marine mammals. Elevated levels of pollutants in Puget Sound, Washington salmon and killer whale tissues potentially could be sufficiently high to elicit adverse effects and hamper population recovery efforts. Contaminant transfer and biomagnification of the toxic compounds measured in this study likely contribute to those elevated concentrations. Pacific sand lance tissues from nine locations were analyzed for a suite of legacy and emerging contaminants including polychlorinated biphenyls, polybrominated diphenyl ethers, chlorinated pesticides, polycyclic aromatic hydrocarbons, alkylphenols, and chlorinated paraffins. Chemicals were detected at all sites generally below available health effect levels for the host. However, sub-lethal effects are known to occur and additive effects from exposure to multiple compounds, like this study’s mixture, are not well understood. Biomagnification calculations suggest that, in some locations, concentrations of polychlorinated biphenyls in forage fish could result in predator tissue concentrations that exceed effect levels.

Washington↗

USGS2011

Dynamics of a plant-herbivore-predator system with plant-toxicity

A system of ordinary differential equations is considered that models the interactions of two plant species populations, an herbivore population, and a predator population. We use a toxin-determined functional response to describe the interactions between plant species and herbivores and use a Holling Type II functional response to model the interactions between herbivores and predators. In order to study how the predators impact the succession of vegetation, we derive invasion conditions under which a plant species can invade into an environment in which another plant species is co-existing with a herbivore population with or without a predator population. These conditions provide threshold quantities for several parameters that may play a key role in the dynamics of the system. Numerical simulations are conducted to reinforce the analytical results. This model can be applied to a boreal ecosystem trophic chain to examine the possible cascading effects of predator-control actions when plant species differ in their levels of toxic defense.

Mathematical Biosciences↗

USGS2024

Hormetic and transcriptomic responses of the toxic alga Prymnesium parvum to glyphosate

Growth of the toxic alga Prymnesium parvum is hormetically stimulated with environmentally relevant concentrations of glyphosate. The mechanisms of glyphosate hormesis in this species, however, are unknown. We evaluated the transcriptomic response of P. parvum to glyphosate at concentrations that stimulate maximum growth and where growth is not different from control values, the zero-equivalent point (ZEP). Maximum growth occurred at 0.1 mg l −1 and the ZEP was 2 mg l −1 . At 0.1 mg l −1 , upregulated transcripts outnumbered downregulated transcripts by one order of magnitude. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses indicated that the upregulated transcriptome is primarily associated with metabolism and biosynthesis. Transcripts encoding heat shock proteins and co-chaperones were among the most strongly upregulated, and several others were associated with translation, Redox homeostasis, cell replication, and photosynthesis. Although most of the same transcripts were also upregulated at concentrations ≥ZEP, the proportion of downregulated transcripts greatly increased as glyphosate concentrations increased. At the ZEP, downregulated transcripts were associated with photosynthesis, cell replication, and anion transport, indicating that specific interference with these processes is responsible for the nullification of hormetic growth. Transcripts encoding the herbicidal target of glyphosate, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), were upregulated at concentrations ≥ZEP but not at 0.1 mg l −1 , indicating that disruption of EPSPS activity occurred at high concentrations and that nullification of hormetic growth involves the direct interaction of glyphosate with this enzyme. Results of this study may contribute to a better understanding of glyphosate hormesis and of anthropogenic factors that influence P. parvum biogeography and bloom formation.

Science of the Total Environment↗

USGS1998

Evaluation of the toxicity and efficacy of hydrogen peroxide treatments on eggs of warm- and coolwater fishes

The use of hydrogen peroxide in aquaculture is growing and there is a need to develop fundamental guidelines to effectively treat diseased fish. The safety (toxicity) of hydrogen peroxide treatments was determined on eggs of representative warm- and coolwater fish species. Eggs of northern pike ( Esox lucius ), walleye ( Stizostedion vitreum ), yellow perch ( Perca flavescens ), white sucker ( Catostomus commersoni ), lake sturgeon ( Acipenser fulvescens ), paddlefish ( Polyodon spathula ), common carp ( Cyprinus carpio ), and channel catfish ( Ictalurus punctatus ) were cultured in egg jars or aquaria. Treatments were initiated with non-eyed eggs and continued until all viable eggs had hatched. Eggs were treated daily for 15 min Monday through Friday with either 0, 500, 1000, 3000, or 6000 μ l l −1 of hydrogen peroxide. For all species, the mean percent hatch was greater in eggs treated with 1000 μ l l −1 hydrogen peroxide for 15 min than in the untreated controls. Common carp, lake sturgeon, and paddlefish were the least sensitive to hydrogen peroxide with percent hatch ranging from 40 to 48% in the 6000 μ l l −1 hydrogen peroxide treatment. Fungal infections reduced or eliminated the hatch in most controls whereas nearly all treated eggs remained free of infection; hydrogen peroxide inhibited fungal infections on fish eggs.

Aquaculture↗

USGS1999

Acute toxicity of hydrogen peroxide treatments to selected lifestages of cold-, cool-, and warmwater fish

Hatchery personnel depend on therapeutant treatments to control diseases. Currently, hatchery managers in the United States are limited to one approved therapeutant (formalin) and three compounds of Low Regulatory Priority (sodium chloride, hydrogen peroxide, and acetic acid) to control external diseases of cultured fish. Hydrogen peroxide has been used to effectively control external columnaris and bacterial gill disease in rainbow trout, however, definitive safe treatment concentrations for hydrogen peroxide are lacking for a variety of species. We report the acute toxicity of hydrogen peroxide treatments to 11 species of fry and 13 species of fingerling freshwater fish. Most mortality occurred within the first 30 h after the first exposure to hydrogen peroxide with little change in the overall shape of survival curves over time. Our data predict that in an actual therapeutic application of hydrogen peroxide, most treatment-related mortalities would be observed shortly after the initial exposure. Coolwater species were more sensitive than coldwater species but were generally similar to warmwater species tested. Based on our mortality data, coldwater species and largemouth bass may be treated for 60 min at concentrations of ??? 150 ??l/l without harmful effects; all muskellunge, walleye, bluegill, channel catfish, yellow perch, pallid sturgeon fingerlings, fathead minnow fingerlings, white sucker fingerlings, and northern pike fry may be treated for 60 min at ??? 100 ??l/l; and northern pike fingerlings and white sucker, yellow perch and fathead minnow fry may be treated for 60 min at ??? 50 ??l/l.

Aquaculture↗

USGS2002

Toxicity of selenium and other elements in food organisms to razorback sucker larvae

Elevated selenium concentrations documented in water, sediment, and biota in irrigation drain water studies by U.S. Department of the Interior agencies and academia have raised concerns that selenium may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine the effects on endangered razorback sucker ( Xyrauchen texanus ) larvae from exposure to selenium and other trace elements in water and zooplankton collected from sites adjacent to the Colorado River near Grand Junction, CO. A 30-day study was initiated with 5-day-old larvae exposed in a 4×4 factor experiment with four food and four water treatments, and the biological endpoints measured were survival, growth, development, and whole-body residues of selenium. Mean selenium concentration in reference water (24-Road) was <0.7 μg/l, in reference food (brine shrimp) was 3.2 μg/g, at Horsethief was 1.6 μg/l in water and 6.0 μg/g in zooplankton, at Adobe Creek was 3.4 μg/l in water and 32 μg/g in zooplankton, and at Walter Walker was 13 μg/l in water and 52 μg/g in zooplankton. Although there were differences in concentrations of inorganic elements in water and biota among the three sites, selenium was apparently the only element elevated to concentrations of concern. Effects on survival were more prominent from dietary exposure compared to waterborne exposure. Selenium concentrations of ≥4.6 μg/g in food organisms adversely affected the survival of razorback sucker larvae. The onset of mortality in larvae exposed to food and water from Walter Walker seemed delayed compared to mortality in larvae exposed to food and water from Horsethief, which has been observed in two other studies. Elevated arsenic in one food source seemed to interact with selenium to reduce the toxic effects of selenium.

Colorado↗

USGS1991

Reproductive outcomes in colonial fish-eating birds: A biomarker for developmental toxicants in Great Lakes food chains: I. Historical and ecotoxicological perspectives

Colonial fish-eating birds have been used as convenient model populations in which to study the impact of chronic exposure to complex mixtures of persistent lipophilic environmental contaminants within the Great Lakes ecosystem. To date, published reports of contaminant-induced adverse reproductive outcomes exist for six species. We briefly review the studies of the herring gull ( Larus argentatu s), Forster's tern ( Sterna forsteri ), and the double-crested cormorant ( Phalacrocorax auritus ) to illustrate the use of reproductive outcomes in fish-eating birds as a biomarkerfor developmental toxicants in Great Lakes food chains. We discuss the management implications of using various species for such purposes. We recommend that cormorants be used more extensively in biomonitoring programs to measure exposure and effects of polyhalogenated aromatic hydrocarbons and other contaminants in aquatic food chains in the Great Lakes.

Great Lakes↗

USGS2024

Multigenerational, indirect exposure to pyrethroids demonstrates potential compensatory response and reduced toxicity at higher salinity in estuarine fish

Estuarine environments are critical to fish species and serve as nurseries for developing embryos and larvae. They also undergo daily fluctuations in salinity and act as filters for pollutants. Additionally, global climate change (GCC) is altering salinity regimes within estuarine systems through changes in precipitation and sea level rise. GCC is also likely to lead to an increased use of insecticides to prevent pests from damaging agricultural crops as their habitats and mating seasons change from increased temperatures. This underscores the importance of understanding how insecticide toxicity to fish changes under different salinity conditions. In this study, larval Inland Silversides ( Menidia beryllina ) were exposed to bifenthrin (1.1 ng/L), cyfluthrin (0.9 ng/L), or cyhalothrin (0.7 ng/L) at either 6 or 10 practical salinity units (PSU) for 96 h during hatching, with a subset assessed for end points relevant to neurotoxicity and endocrine disruption by testing behavior, gene expression of a select suite of genes, reproduction, and growth. At both salinities, directly exposed F0 larvae were hypoactive relative to the F0 controls; however, the indirectly exposed F1 larvae were hyperactive relative to the F1 control. This could be evidence of a compensatory response to environmentally relevant concentrations of pyrethroids in fish. Effects on development, gene expression, and growth were also observed. Overall, exposure to pyrethroids at 10 PSU resulted in fewer behavioral and endocrine disruptive effects relative to those observed in organisms at 6 PSU.

Environmental Science and Technology↗

USGS2016

Dietary uptake of Cu sorbed to hydrous iron oxide is linked to cellular toxicity and feeding inhibition in a benthic grazer

Whereas feeding inhibition caused by exposure to contaminants has been extensively documented, the underlying mechanism(s) are less well understood. For this study, the behavior of several key feeding processes, including ingestion rate and assimilation efficiency, that affect the dietary uptake of Cu were evaluated in the benthic grazer Lymnaea stagnalis following 4–5 h exposures to Cu adsorbed to synthetic hydrous ferric oxide (Cu–HFO). The particles were mixed with a cultured alga to create algal mats with Cu exposures spanning nearly 3 orders of magnitude at variable or constant Fe concentrations, thereby allowing first order and interactive effects of Cu and Fe to be evaluated. Results showed that Cu influx rates and ingestion rates decreased as Cu exposures of the algal mat mixture exceeded 10 4 nmol/g. Ingestion rate appeared to exert primary control on the Cu influx rate. Lysosomal destabilization rates increased directly with Cu influx rates. At the highest Cu exposure where the incidence of lysosomal membrane damage was greatest (51%), the ingestion rate was suppressed 80%. The findings suggested that feeding inhibition was a stress response emanating from excessive uptake of dietary Cu and cellular toxicity.

Environmental Science & Technology↗

USGS2009

Predicting dietborne metal toxicity from metal influxes

Dietborne metal uptake prevails for many species in nature. However, the links between dietary metal exposure and toxicity are not well understood. Sources of uncertainty include the lack of suitable tracers to quantify exposure for metals such as copper, the difficulty to assess dietary processes such as food ingestion rate, and the complexity to link metal bioaccumulation and effects. We characterized dietborne copper, nickel, and cadmium influxes in a freshwater gastropod exposed to diatoms labeled with enriched stable metal isotopes. Metal influxes in Lymnaea stagnalis correlated linearly with dietborne metal concentrations over a range encompassing most environmental exposures. Dietary Cd and Ni uptake rate constants (k uf ) were, respectively, 3.3 and 2.3 times higher than that for Cu. Detoxification rate constants (k detox ) were similar among metals and appeared 100 times higher than efflux rate constants (k e ). Extremely high Cu concentrations reduced feeding rates, causing the relationship between exposure and influx to deviate from linearity; i.e., Cu uptake rates leveled off between 1500 and 1800 nmol g -1 day -1 . L. stagnalis rapidly takes up Cu, Cd, and Ni from food but detoxifies the accumulated metals, instead of reducing uptake or intensifying excretion. Above a threshold uptake rate, however, the detoxification capabilities of L. stagnalis are overwhelmed.

Environmental Science & Technology↗

USGS2002

Pesticide toxicity, effects of chlorinated hydrocarbon insecticides upon quail and pheasants

Previous studies had shown that heavy or repeated applications of DDT resulted in decreases.in bird populations, but long-range effects of this and other chlorinated hydrocarbon insecticides had not been fully evaluated. Experiments were conducted to determine toxiCitY to quail and pheasants of aldrin, dieldrin, endrin, and strobane, and to determine effects of these compounds upon survival, growth, and reproduction....Feeding of diets containing 0.02% DDT to breeding quail resulted in significant decreases in hatchability of eggs and in viability of chiCks. Similar results were obtained by feeding 0.001% dieldrin, but effects upon reproduct.ion of short-term feeding of aldrin and endrin could not be determined....Aldrin, dieldrin, and endrin were lethal to both male and female quail when fed at levels of 0.0005% in the diets. Female pheasants appeared more resistant than males to the effects of these compounds.

Journal of Agricultural and Food Chemistry↗

USGS2001

Estimating toxic damage to soil ecosystems from soil organic matter profiles

Concentrations of particulate and total organic matter were measured in upper soil profiles at 26 sites as a potential means to identify toxic damage to soil ecosystems. Because soil organic matter plays a role in cycling nutrients, aerating soil, retaining water, and maintaining tilth, a significant reduction in organic matter content in a soil profile is not just evidence of a change in ecosystem function, but of damage to that soil ecosystem. Reference sites were selected for comparison to contaminated sites, and additional sites were selected to illustrate how variables other than environmental contaminants might affect the Soil organic matter profile. The survey was undertaken on the supposition that environmental contaminants and other stressors reduce the activity of earthworms and other macrofauna, inhibiting the incorporation of organic matter into the soil profile. The profiles of the unstressed soils showed a continuous decrease in organic matter content from the uppermost mineral soil layer (0-2.5 cm) down to 15 cm. Stressed soils showed an abrupt decrease in soil organic matter content below a depth of 2.5 cm. The 2.5-5.0 cm layer of stressed soils--such as found in a pine barren, an orchard, sites contaminated with zinc, and a site with compacted soil--had less than 4% total organic matter and less than 1% particulate organic matter. However, damaged soil ecosystems were best identified by comparison of their profiles to the profiles of closely matched reference soils, rather than by comparison to these absolute values. The presence or absence of earthworms offered a partial explanation of observed differences in soil organic matter profiles.

Ecotoxicology↗

USGS2014

Isotopically modified silver nanoparticles to assess nanosilver bioavailability and toxicity at environmentally relevant exposures

A major challenge in understanding the environmental implications of nanotechnology lies in studying nanoparticle uptake in organisms at environmentally realistic exposure concentrations. Typically, high exposure concentrations are needed to trigger measurable effects and to detect accumulation above background. But application of tracer techniques can overcome these limitations. Here we synthesised, for the first time, citrate-coated Ag nanoparticles using Ag that was 99.7 % 109 Ag. In addition to conducting reactivity and dissolution studies, we assessed the bioavailability and toxicity of these isotopically modified Ag nanoparticles ( 109 Ag NPs) to a freshwater snail under conditions typical of nature. We showed that accumulation of 109 Ag from 109 Ag NPs is detectable in the tissues of Lymnaea stagnalis after 24-h exposure to aqueous concentrations as low as 6 ng L –1 as well as after 3 h of dietary exposure to concentrations as low as 0.07 μg g –1 . Silver uptake from unlabelled Ag NPs would not have been detected under similar exposure conditions. Uptake rates of 109 Ag from 109 Ag NPs mixed with food or dispersed in water were largely linear over a wide range of concentrations. Particle dissolution was most important at low waterborne concentrations. We estimated that 70 % of the bioaccumulated 109 Ag concentration in L. stagnalis at exposures <0.1 µg L –1 originated from the newly solubilised Ag. Above this concentration, we predicted that 80 % of the bioaccumulated 109 Ag concentration originated from the 109 Ag NPs. It was not clear if agglomeration had a major influence on uptake rates.

Environmental Chemistry↗

USGS1999

Use of power analysis to develop detectable significance criteria for sea urchin toxicity tests

When sufficient data are available, the statistical power of a test can be determined using power analysis procedures. The term “detectable significance” has been coined to refer to this criterion based on power analysis and past performance of a test. This power analysis procedure has been performed with sea urchin ( Arbacia punctulata ) fertilization and embryological development data from sediment porewater toxicity tests. Data from 3100 and 2295 tests for the fertilization and embryological development tests, respectively, were used to calculate the criteria and regression equations describing the power curves. Using Dunnett's test, a minimum significant difference (MSD) ( β = 0.05) of 15.5% and 19% for the fertilization test, and 16.4% and 20.6% for the embryological development test, for α ≤ 0.05 and α ≤ 0.01, respectively, were determined. The use of this second criterion reduces type I (false positive) errors and helps to establish a critical level of difference based on the past performance of the test.

Aquatic Ecosystem Health & Management↗

USGS1994

A toxic equivalency factor scale for polychlorinated dibenzofurans

The ethoxyresorufin O -deethylase (EROD) induction of 20 polychiorinated dibenzofurans (PCDFs) was examined in the H4IIE rat hepatoma cell bioassay. The selection of the compounds tested was based on a multivariate chemical characterization laying the groundwork for covering the whole chemical series of PCDFs. The EROD induction potency was found to vary in ED50 values from 25 to 100,000,000 pg/mg, i.e., nearly seven orders of magnitude. The response of the bioassay was calibrated against the 2,3,7,8-tetrachlorodibenzo- p -dioxin, enabling the corresponding toxic equivalency factors (TEFs) to be calculated. In order to establish a quantitative structure-activity relationship (QSAR) for the TEF values, 37 physicochemical descriptor variables were used to chemically characterize the 87 tetra- to octachlorinated PCDFs. Using partial least-squares modeling on a training set of 10 congeners, a QSAR model with sound predictive power was obtained. The QSAR model was validated with a validation set of additional 10 congeners. The predicted TEFs indicate that a large number of congeners are potent EROD inducers.

Toxicological Sciences↗

USGS1973

Toxicity of TFM (lampricide) to six early stages of rainbow trout (Salmo gairdneri)

The lampricide TFM (3-trifluoromethyl-4-nitrophenol) was tested against the following life stages of rainbow trout ( Salmo gairdneri ): green eggs, eyed eggs, sac fry, swim-up fry, fry, and fingerlings in four water hardnesses (12, 44, 170, and 320 mg/liter as CaCO 3 ). The eyed-egg stage was one of the most resistant stages tested, and the sac-fry stage was one of the least resistant. Increased water hardness decreases toxicity to all stages. The LC50’s range from 0.532 mg/liter to 40.0 mg/liter depending upon life stage, water hardness, and duration of exposure. The margin of safety for coexisting species exposed to TFM ranges from 3.2 to 4.1 in natural waters. The margin of safety for early life stages of rainbow trout and larval lamprey under controlled laboratory conditions ranges from 4.2 to 12.2. Therefore, all six early life stages of rainbow trout are safe in minimum lampricidal concentrations of TFM.

Journal of the Fisheries Research Board of Canada↗

USGS2003

Determination of the median toxic dose of type C botulism in lactating dairy cows

Because of the difficulty in identifying botulinum toxin in cattle, it is hypothesized that cattle are sensitive to levels of toxin below the detection limits of current diagnostic techniques (the mouse protection bioassay and the immunostick enzyme-linked immunosorbent assay [ELISA] for type C botulinum toxin). Using an up-down method for toxicologic testing, the median toxic dose (MTD50) for cattle was determined. Four lactating Holstein cows were dosed at 0.125 or 0.25 ng/kg with Clostridium botulinum type C toxin and failed to develop clinical signs of botulism during the 7-day observation period. Three cows given 0.50 ng/kg of toxin developed clinical signs of botulism. From these results, the MTD50 was calculated at 0.388 ng/kg (3.88 mouse lethal doses/kg) using the trim-logit method. These results suggest that cattle are 12.88 times more sensitive to type C botulinum toxin than a mouse on a per kilogram weight basis. The mouse protection bioassay and the immunostick ELISA for type C botulinum toxin failed to identify the presence of the toxin in the serum, blood, and milk samples taken from all 7 animals.

Journal of Veterinary Diagnostic Investigation↗