Environmental Concentrations (environmental + concentration)

Distribution by Scientific Domains


Selected Abstracts


Environmental concentrations of methoprene and its transformation products after the treatment of Altosid® XR Briquets in the city of Richmond, British Columbia, Canada

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2010
Jen-ni Kuo
Abstract Water runoff from catch basins treated with Altosid® XR Briquets for mosquito larvae control was sampled at 10 storm drainage pump stations along the outskirts of the city of Richmond, British Columbia, Canada after rainfall events in 2006 to determine the residual concentrations of methoprene and transformation products: citronellic acid, methoprene acid, and 7-methoxycitronellic acid. Runoff of prior-to-treatment, posttreatment, and 150-d-after-treatment was collected. No residues were detected in the prior-to-treatment samples. However, methoprene was detected in posttreatment, and citronellic acid was detected in posttreatment and one 150-d-after-treatment sample. The detected environmental concentrations of methoprene (0.04,0.14,µg/L) and methoprene acid (0.07,µg/L) at pump stations were below known/reported toxicity values to aquatic organisms. However, concentrations detected inside the storm drainage system in catch basins (methoprene 122,µg/L, methoprene acid 1.74,µg/L) and inspection chambers (methoprene 622,µg/L, methoprene acid 20,µg/L, citronellic acid 0.05,µg/L) are known to be toxic to invertebrates, have chronic early-life-stage fish effects, and exceeded the Draft Interim Ontario Water Quality Objective and the numerical benchmarks for protection of amphibians (1.6,µg/L), invertebrates (10,µg/L), and fish (80,µg/L). The limited detection in the present study may have resulted from significant absorption of methoprene to sample bottle walls, substance decay during sample storage before methoprene extraction, flushing of briquettes from catch basins following heavy rainfall, and the burial of briquettes under thick layers of debris. Environ. Toxicol. Chem. 2010;29:2200,2205. © 2010 SETAC [source]


Toxicity of fluoroquinolone antibiotics to aquatic organisms

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2005
April A. Robinson
Abstract Toxicity tests were performed with seven fluoroquinolone antibiotics, ciprofloxacin, lomefloxacin, ofloxacin, levofloxacin, clinafloxacin, enrofloxacin, and flumequine, on five aquatic organisms. Overall toxicity values ranged from 7.9 to 23,000 ,g/L. The cyanobacterium Microcystis aeruginosa was the most sensitive organism (5-d growth and reproduction, effective concentrations [EC50s] ranging from 7.9 to 1,960 ,g/L and a median of 49 ,g/L), followed by duckweed (Lemna minor, 7-d reproduction, EC50 values ranged from 53 to 2,470 ,g/L with a median of 106 ,g/L) and the green alga Pseudokirchneriella subcapitata (3-d growth and reproduction, EC50 values ranged from 1,100 to 22,700 ,g/L with a median 7,400 ,g/L). Results from tests with the crustacean Daphnia magna (48-h survival) and fathead minnow (Pimephales promelas, 7-d early life stage survival and growth) showed limited toxicity with no-observed-effect concentrations at or near 10 mg/L. Fish dry weights obtained in the ciprofloxacin, levofloxacin, and ofloxacin treatments (10 mg/L) were significantly higher than in control fish. The hazard of adverse effects occurring to the tested organisms in the environment was quantified by using hazard quotients. An estimated environmental concentration of 1 ,g/L was chosen based on measured environmental concentrations previously reported in surface water; at this level, only M. aeruginosa may be at risk in surface water. However, the selective toxicity of these compounds may have implications for aquatic community structure. [source]


Comparative effects of pH and Vision® herbicide on two life stages of four anuran amphibian species,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2004
Andrea N. Edginton
Abstract Vision®, a glyphosate-based herbicide containing a 15% (weight:weight) polyethoxylated tallow amine surfactant blend, and the concurrent factor of pH were tested to determine their interactive effects on early life-stage anurans. Ninety-six-hour laboratory static renewal studies, using the embryonic and larval life stages (Gosner 25) of Rana clamitans, R. pipiens, Bufo americanus, and Xenopus laevis, were performed under a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach for obtaining confidence intervals. There was a significant (p < 0.05) interaction of pH with Vision concentration in all eight models, such that the toxicity of Vision was amplified by elevated pH. The surfactant is the major toxic component of Vision and is hypothesized, in this study, to be the source of the pH interaction. Larvae of B. americanus and R. clamitans were 1.5 to 3.8 times more sensitive than their corresponding embryos, whereas X. laevis and R. pipiens larvae were 6.8 to 8.9 times more sensitive. At pH values above 7.5, the Vision concentrations expected to kill 50% of the test larvae in 96-h (96-h lethal concentration [LC50]) were predicted to be below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities. The EEC value represents a worst-case scenario for aerial Vision application and is calculated assuming an application of the maximum label rate (2.1 kg acid equivalents [a.e.]/ha) into a pond 15 cm in depth. The EEC of 1.4 mg a.e./L (4.5 mg/L Vision) was not exceeded by 96-h LC50 values for the embryo test. The larvae of the four species were comparable in sensitivity. Field studies should be completed using the more sensitive larval life stage to test for Vision toxicity at actual environmental concentrations. [source]


Fragrance materials and their environmental impact

FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2004
Daniel T. Salvito
Abstract A brief discussion on the environmental fate and effects of fragrance materials was recently presented in Cadby et al.1. This paper has been prepared as a more detailed discussion of the environmental effects associated with fragrance materials. Cadby et al.1 presented a detailed discussion of the rigorous science employed to protect the consumer and the environment from adverse effects from these materials. The Research Institute for Fragrance Materials (RIFM) has established a comprehensive environmental research and testing programme to determine the potential environmental risks posed by fragrance materials to the environment. Sponsored research and testing includes ecotoxicological studies, the biotransformation of fragrance materials in wastewater treatment, and their fate in the terrestrial environment. RIFM has published a conservative screening level risk assessment model following established environmental risk assessment paradigms (i.e. the predicted environmental concentration: predicted no effect concentration quotient; the PEC,PNEC ratio).2 In an initial screening of all discrete fragrance materials, using only volume of use and available physical-chemical parameters, 92% of these materials are shown to pose an acceptable environmental risk, i.e. their PEC,PNEC ratio is less than 1. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Environmental risk assessment of human pharmaceuticals in the European Union: A case study with the ,-blocker atenolol

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue S1 2010
Anette Küster
Abstract ,-Adrenergic receptor blockers (,-blockers) are applied to treat high blood pressure, ischemic heart disease, and heart rhythm disturbances. Due to their widespread use and limited human metabolism, ,-blockers are widely detected in sewage effluents and surface waters. ,-Adrenergic receptors have been characterized in fish and other aquatic animals, so it can be expected that physiological processes regulated by these receptors in wild animals may be affected by the presence of ,-blockers. Because ecotoxicological data on ,-blockers are scarce, it was decided to choose the ,-blocker atenolol as a case study pharmaceutical within the project ERAPharm. A starting point for the assessment of potential environmental risks was the European guideline on the environmental risk assessment of medicinal products for human use. In Phase I of the risk assessment, the initial predicted environmental concentration (PEC) of atenolol in surface water (500,ng L,1) exceeded the action limit of 10,ng L,1. Thus, a Phase II risk assessment was conducted showing acceptable risks for surface water, for groundwater, and for aquatic microorganisms. Furthermore, atenolol showed a low potential for bioaccumulation as indicated by its low lipophilicity (log KOW,=,0.16), a low potential for exposure of the terrestrial compartment via sludge (log KOC,=,2.17), and a low affinity for sorption to the sediment. Thus, the risk assessment according to Phase II-Tier A did not reveal any unacceptable risk for atenolol. Beyond the requirements of the guideline, additional data on effects and fate were generated within ERAPharm. A 2-generation reproduction test with the waterflea Daphnia magna resulted in the most sensitive no-observed-effect concentration (NOEC) of 1.8,mg L,1. However, even with this NOEC, a risk quotient of 0.003 was calculated, which is still well below the risk threshold limit of 1. Additional studies confirm the outcome of the environmental risk assessment according to EMEA/CHMP (2006). However, atenolol should not be considered as representative for other ,-blockers, such as metoprolol, oxprenolol, and propranolol, some of which show significantly different physicochemical characteristics and varying toxicological profiles in mammalian studies. Integr Environ Assess Manag 2010;6:514,523. © 2009 SETAC [source]


Risk assessment of pesticides for soils of the central amazon, Brazil: Comparing outcomes with temperate and tropical data

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2008
Jörg Römbke
Abstract The risk of 11 pesticides to the soil environment was assessed in a 3-tiered approach at 4 sites located in Central Amazon, near Manaus, the capital of the Amazonas State in Brazil. Toxicity-exposure ratios (TERs), as routinely used for the registration of pesticides in the European Union, were calculated. First, the predicted environmental concentration (PEC) values in soil on the basis of real application rates and soil properties but temperate DT50 (degradation time of 50%) values were compared with temperate effect values (earthworm LC50s; median lethal concentrations), both gained from literature. Second, the risk assessment was refined by the use of DT50 values from tropical soils (measured for 7 compounds and estimated for 4) but still with temperate effect values because only a few results from tests performed under tropical conditions are available. Third, the outcome of this exercise was evaluated in a plausibility check with the use of the few results of effect tests, which were performed under tropical conditions. However, the lack of such data allowed this check only for 6 of 11 pesticides. The results are discussed in light of pesticide use in the Amazon in general, as well as compared with the registration status of these pesticides in other countries. Finally, suggestions are given for which kinds of studies are needed to improve the environmental risk assessment of pesticides in tropical regions. [source]


Chlorpyrifos residue levels in avian food items following applications of a commercial EC formulation to alfalfa and citrus

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 11 2003
Larry W Brewer
Abstract Two 10-day field residue studies were conducted to measure the amount of chlorpyrifos residue found in typical avian food following applications of a commercial 480 g liter,1 EC (Lorsban® 4E) at 1.1 kg AI ha,1 (1 lb AI acre,1) to alfalfa and at 2.3 kg AI ha,1 (2.0 lb AI acre,1) to citrus. Avian food items used in these studies included: crickets (Acheta domestica (L)), earthworms (Lumbricus terrestris L), darkling ground beetle larvae (Tenebrio molitor L), seed heads (Triticum sp), and naturally occurring flying and ground-dwelling insects. The studies incorporated a design involving three main study plots placed within larger treated areas of an alfalfa crop and a mature orange grove. The three main study plots represented three replications and each contained four sub-plots. One sub-plot, on each study plot, was sampled on day 0 (2-h post-application), day 1, day 5 and day 10 post-application. Chlorpyrifos residues were present in all avian food sampled following the application; however, residue levels were lower than estimated residue values typically used by the US EPA to establish expected environmental concentration (EEC) used in screening assessments of risk to terrestrial wildlife. Copyright © 2003 Society of Chemical Industry [source]


Determination of urinary S -phenylmercapturic acid, a specific metabolite of benzene, by liquid chromatography/single quadrupole mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2005
Luciano Maestri
A high-performance liquid chromatography/single quadrupole mass spectrometry (LC/MS) method is described for the determination of urinary S -phenylmercapturic acid (S-PMA), a specific metabolite of benzene. Urine samples were spiked with [13C6]S-PMA (used as the internal standard) and acidified; then they were purified by solid-phase extraction (SPE) on C18 cartridges. Analyses were conducted on a reversed-phase column by gradient runs with 1% aqueous acetic acid/methanol mixtures at different proportions as the mobile phase. The detector was used in electrospray negative ion mode (ESI,), the ions m/z 238 for S-PMA and 244 for [13C6]S-PMA being recorded simultaneously. The detection limit (for a signal-to-noise ratio,=,3) was 0.2,,g/L, thus allowing for the measurement of background excretion of S-PMA in the general population. The use of the internal standard allowed us to obtain good precision (CV% values <3%) and a linear calibration curve within the range of interest for monitoring occupational exposure to benzene (up to 500,,g/L). The method was applied to assay the metabolite concentration in a group of 299 workers (68 smokers and 231 non-smokers) occupationally exposed to relatively low levels of benzene (environmental concentration,=,0.4,220,,g/m3, mean 11.4,,g/m3) and 236 non-exposed subjects (134 smokers and 102 non-smokers). The results clearly showed that smoking must be taken into account for the correct interpretation of the results of S-PMA measurements for the assessment of work-related benzene exposure. When only non-smokers were selected, the mean excretion of S-PMA was significantly higher in workers exposed to benzene (1.2,±,0.9,,g/g creatinine) than in the control group (0.7,±,0.6,,g/g creatinine) (p,<,0.001), thus confirming the role of S-PMA as a biomarker of benzene on a group basis, even for relatively low exposure degrees. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Occurrence and fate of micropollutants in the Vidy Bay of Lake Geneva, Switzerland.

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2010
Part II: Micropollutant removal between wastewater, raw drinking water
Abstract The occurrence and removal of 58 pharmaceuticals, endocrine disruptors, corrosion inhibitors, biocides, and pesticides, were assessed in the wastewater treatment plant (WWTP) of the city of Lausanne, Switzerland, as well as in the effluent-receiving water body, the Vidy Bay of Lake Geneva. An analytical screening method to simultaneously measure all of the 58 micropollutants was developed based on ultra performance liquid chromatography coupled to a tandem mass spectrometer (UPLC-MS/MS). The selection of pharmaceuticals was primarily based on a prioritization study, which designated them as environmentally relevant for the Lake Geneva region. Except for the endocrine disruptor 17,-ethinylestradiol, all substances were detected in 24-h composite samples of wastewater entering the WWTP or in the treated effluent. Of these compounds, 40% were also detected in raw drinking water, pumped from the lake 3,km downstream of the WWTP. The contributions of dilution and degradation to micropollutant elimination between the WWTP outlet and the raw drinking water intake were established in different model scenarios using hypothetical residence times of the wastewater in Vidy Bay of 1, 4, or 90 d. Concentration decrease due to processes other than dilution was observed for diclofenac, beta-blockers, several antibiotics, corrosion inhibitors, and pesticides. Measured environmental concentrations (MECs) of pharmaceuticals were compared to the predicted environmental concentrations (PECs) determined in the prioritization study and agreed within one order of magnitude, but MECs were typically greater than the corresponding PECs. Predicted no-effect concentrations of the analgesic paracetamol, and the two antibiotics ciprofloxacin and sulfamethoxazole, were exceeded in raw drinking water samples and therefore present a potential risk to the ecosystem. Environ. Toxicol. Chem. 2010; 29:1658,1668. © 2010 SETAC [source]


Exposure assessment of 17,-ethinylestradiol in surface waters of the United States and Europe,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2009
Robert Hannah
Abstract An evaluation of measured and predicted concentrations of 17,-ethinylestradiol in surface waters of the United States and Europe was conducted to develop expected long-term exposure concentrations for this compound. Measured environmental concentrations (MECs) in surface waters were identified from the literature. Predicted environmental concentrations (PECs) were generated for European and U.S. watersheds using the GREAT-ER and PhATEŌ models, respectively. The majority of MECs are nondetect and generally consistent with model PECs and conservative mass balance calculations. However, the highest MECs are not consistent with concentrations derived from conservative (worst-case) mass balance estimates or model PECs. A review of analytical methods suggests that tandem or high-resolution mass spectrometry methods with extract cleanup result in lower detection limits and lower reported concentrations consistent with model predictions and bounding estimates. Based on model results using PhATE and GREAT-ER, the 90th-percentile low-flow PECs in surface water are approximately 0.2 and 0.3 ng/L for the United States and Europe, respectively. These levels represent conservative estimates of long-term exposure that can be used for risk assessment purposes. Our analysis also indicates that average concentrations are one to two orders of magnitude lower than these 90th-percentile estimates. Higher reported concentrations (e.g., greater than the 99th-percentile PEC of ,1 ng/L) could result from methodological problems or unusual environmental circumstances; however, such concentrations are not representative of levels generally found in the environment, warrant special scrutiny, and are not appropriate for use in risk assessments of long-term exposures. [source]


Examining the single and interactive effects of three insecticides on amphibian metamorphosis,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2008
Michelle D. Boone
Abstract Although aquatic communities frequently are exposed to a number of pesticides, the effects of chemical mixtures are not well understood. In two separate studies, I examined how insecticide mixtures influenced the likelihood of unpredictable, nonadditive effects on American toad (Bufo americanus) and green frog (Rana clamitans) tadpoles reared in outdoor aquatic communities. I exposed tadpoles to single or multiple insecticides at approximately half the reported median lethal concentrations using insecticides that were either acetylcholinesterase inhibitors (carbaryl or malathion) or a sodium-channel disruptor (permethrin). I found that combinations of insecticides with the same mode of action were more likely to have nonadditive effects on amphibian metamorphosis compared with those having different modes of action. Additionally, in one study, a commercial formulation of permethrin led to near-complete elimination of American toads, suggesting that this formulation could have adverse effects on aquatic communities. Many community studies exploring the ecological effects of expected environmental concentrations of pesticides have suggested that indirect effects in the food web, rather than direct effects on individual physiology, have the largest effect on amphibians. The present study indicates that direct effects of pesticides may become particularly important when insecticides with the same mode of action are present in the environment. [source]


Prediction of large variation in biota to sediment accumulation factors due to concentration-dependent black carbon adsorption of planar hydrophobic organic compounds

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2005
Gerard Cornelissen
Abstract Biota-to-sediment accumulation factors (BSAFs) sometimes show large variations between sites for a given planar hydrophobic organic compound (pHOC) in a given organism. We present a framework in which strong adsorption to soot/charcoal (black carbon [BC]) explains such BSAF variations. Recently constrained parameters on environmental BC sorption were used in a dual-mode sorption model of BSAF. Variations in sedimentary BC content are shown to explain variations in BSAF of one to two orders of magnitude. In addition, strong BC sorption can explain the often-observed difference in BSAF between polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The strong nonlinearity of BC sorption can render BSAF values strongly concentration-dependent for a given sediment/organism/compound combination, so it is of paramount importance to carry out uptake and toxicity tests at the relevant environmental concentrations. [source]


Toxicity of fluoroquinolone antibiotics to aquatic organisms

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2005
April A. Robinson
Abstract Toxicity tests were performed with seven fluoroquinolone antibiotics, ciprofloxacin, lomefloxacin, ofloxacin, levofloxacin, clinafloxacin, enrofloxacin, and flumequine, on five aquatic organisms. Overall toxicity values ranged from 7.9 to 23,000 ,g/L. The cyanobacterium Microcystis aeruginosa was the most sensitive organism (5-d growth and reproduction, effective concentrations [EC50s] ranging from 7.9 to 1,960 ,g/L and a median of 49 ,g/L), followed by duckweed (Lemna minor, 7-d reproduction, EC50 values ranged from 53 to 2,470 ,g/L with a median of 106 ,g/L) and the green alga Pseudokirchneriella subcapitata (3-d growth and reproduction, EC50 values ranged from 1,100 to 22,700 ,g/L with a median 7,400 ,g/L). Results from tests with the crustacean Daphnia magna (48-h survival) and fathead minnow (Pimephales promelas, 7-d early life stage survival and growth) showed limited toxicity with no-observed-effect concentrations at or near 10 mg/L. Fish dry weights obtained in the ciprofloxacin, levofloxacin, and ofloxacin treatments (10 mg/L) were significantly higher than in control fish. The hazard of adverse effects occurring to the tested organisms in the environment was quantified by using hazard quotients. An estimated environmental concentration of 1 ,g/L was chosen based on measured environmental concentrations previously reported in surface water; at this level, only M. aeruginosa may be at risk in surface water. However, the selective toxicity of these compounds may have implications for aquatic community structure. [source]


Acute and chronic toxicity of five selective serotonin reuptake inhibitors in Ceriodaphnia dubia

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2004
Theodore B. Henry
Abstract Contamination of surface waters by pharmaceutical chemicals has raised concern among environmental scientists because of the potential for negative effects on aquatic organisms. Of particular importance are pharmaceutical compounds that affect the nervous or endocrine systems because effects on aquatic organisms are possible at low environmental concentrations. Selective serotonin reuptake inhibitors (SSRIs) are drugs used to treat clinical depression in humans, and have been detected in low concentrations in surface waters. In this investigation, the acute and chronic toxicity of five SSRIs (fluoxetine, Prozac®; fluvoxamine, Luvox®; paroxetine, Paxil®; citalopram, Celexa®; and sertraline, Zoloft®) were evaluated in the daphnid Ceriodaphnia dubia. For each SSRI, the 48-h median lethal concentration (LC50) was determined in three static tests with neonate C. dubia, and chronic (8-d) tests were conducted to determine no-observable-effect concentrations (NOEC) and lowest-observable-effect concentrations (LOEC) for reproduction endpoints. The 48-h LC50 for the SSRIs ranged from 0.12 to 3.90 mg/L and the order of toxicity of the compounds was (lowest to highest): Citalopram, fluvoxamine, paroxetine, fluoxetine, sertraline. Mortality data for the 8-d chronic tests were similar to the 48-h acute data. The SSRIs negatively affected C. dubia reproduction by reducing the number of neonates per female, and for some SSRIs, by reducing the number of broods per female. For sertraline, the most toxic SSRI, the LOEC for the number of neonates per female was 0.045 mg/L and the NOEC was 0.009 mg/L. Results indicate that SSRIs can impact survival and reproduction of C. dubia; however, only at concentrations that are considerably higher than those expected in the environment. [source]


Comparative effects of pH and Vision® herbicide on two life stages of four anuran amphibian species,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2004
Andrea N. Edginton
Abstract Vision®, a glyphosate-based herbicide containing a 15% (weight:weight) polyethoxylated tallow amine surfactant blend, and the concurrent factor of pH were tested to determine their interactive effects on early life-stage anurans. Ninety-six-hour laboratory static renewal studies, using the embryonic and larval life stages (Gosner 25) of Rana clamitans, R. pipiens, Bufo americanus, and Xenopus laevis, were performed under a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach for obtaining confidence intervals. There was a significant (p < 0.05) interaction of pH with Vision concentration in all eight models, such that the toxicity of Vision was amplified by elevated pH. The surfactant is the major toxic component of Vision and is hypothesized, in this study, to be the source of the pH interaction. Larvae of B. americanus and R. clamitans were 1.5 to 3.8 times more sensitive than their corresponding embryos, whereas X. laevis and R. pipiens larvae were 6.8 to 8.9 times more sensitive. At pH values above 7.5, the Vision concentrations expected to kill 50% of the test larvae in 96-h (96-h lethal concentration [LC50]) were predicted to be below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities. The EEC value represents a worst-case scenario for aerial Vision application and is calculated assuming an application of the maximum label rate (2.1 kg acid equivalents [a.e.]/ha) into a pond 15 cm in depth. The EEC of 1.4 mg a.e./L (4.5 mg/L Vision) was not exceeded by 96-h LC50 values for the embryo test. The larvae of the four species were comparable in sensitivity. Field studies should be completed using the more sensitive larval life stage to test for Vision toxicity at actual environmental concentrations. [source]


A dynamic mass budget for toxaphene in North America

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2002
Matthew MacLeod
Abstract A continental-scale dynamic mass budget for toxaphene in North America is presented, based on available information on physicochemical properties, usage patterns, and reported environmental concentrations and using the Berkeley-Trent North American mass balance contaminant fate model (BETR North America). The model describes contaminant fate in 24 ecological regions of North America, including advective transport between regions in the atmosphere, freshwater, and near-shore coastal water. The dynamic mass budget accounts for environmental partitioning, transport, and degradation of the estimated 534 million kg of toxaphene that were used in North America as an insecticide and piscicide between 1945 and 2000. Satisfactory agreement exists between model results and current and historically reported concentrations of toxaphene in air, water, soil, and sediments throughout North America. An estimated 15 million kg of toxaphene are believed to remain in active circulation in the North American environment in the year 2000, with the majority in soils in the southern United States and Mexico, where historic usage was highest. Approximately 70% of total toxaphene deposition from the atmosphere to the Great Lakes is attributed to sources outside the Great Lakes Basin, and an estimated total of 3.9 million kg of toxaphene have been transported to this region from other parts of the continent. The toxaphene mass budget presented here is believed to be the first reported continental-scalemultimedia mass budget for any contaminant. [source]


Response of zooplankton communities to liquid creosote in freshwater microcosms

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2001
Paul K. Sibley
Abstract In this study, the response of zooplankton communities to single applications of liquid creosote in model aquatic ecosystems (microcosms) was evaluated. Liquid creosote was applied to 14 microcosms at concentrations ranging from 0.06 to 109 mg/L. Two microcosms served as controls. Zooplankton samples were collected from each microcosm on days 7 and 1 before treatment and on days 2, 5, 7, 14, 21, 28, 43, 55, and 83 following treatment. Temporal changes (response-recovery) in composition of the zooplankton community were assessed using principal response curves (PRC). Creosote induced a rapid, concentrationdependent reduction in zooplankton abundance and number of taxa, with maximum response (50,100% reduction in population densities) occurring between 5 and 7 d after treatment. Taxa that dominated at the time of treatment experienced the greatest impact, as indicated by large, positive species weight values (>1) from the PRC analysis. Many of these taxa recovered to pretreatment or control levels during the posttreatment period, with the degree and duration of recovery being strongly dependent on concentration. Creosote had little effect on species composition at less than 1.1 mg/L, because changes in the types and relative proportion of species contributed from Cladocera, Rotifera, and Copepoda were comparable to those observed in control microcosms. However, a significant shift in species composition was observed at concentrations greater than 1.1 mg/L; these microcosms were generally dominated by low numbers of rotifers, some of which had not been collected before treatment. Community-level effect concentrations (EC50s) were 44.6 and 46.6 ,g/L at 5 and 7 d, respectively, based on nominal creosote. Corresponding no-effect concentrations were 13.9 and 5.6 ,g/L. The results of this field study indicate that creosote may pose a significant risk to zooplankton communities at environmental concentrations potentially encountered during spills and/or leaching events. [source]


Environmental Exposure of Aquatic and Terrestrial Biota to Triclosan and Triclocarban,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2009
Talia E. A. Chalew
Abstract:, The synthetic biocides triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) and triclocarban (3,4,4,-trichlorocarbanilide) are routinely added to a wide array of antimicrobial personal care products and consumer articles. Both compounds can persist in the environment and exhibit toxicity toward a number of biological receptors. Recent reports of toxicological effects in wildlife, human cell cultures, and laboratory animals have heightened the interest in the occurrence of these biocide and related toxic effects. The present study aimed to summarize published environmental concentrations of biocides and contrast them with toxicity threshold values of susceptible organisms. Environmental occurrences and toxicity threshold values span more than six orders of magnitude in concentration. The highest biocide levels, measured in the mid parts-per-million range, were determined to occur in aquatic sediments and in municipal biosolids destined for land application. Crustacea and algae were identified as the most sensitive species, susceptible to adverse effects from biocide exposures in the parts-per-trillion range. An overlap of environmental concentrations and toxicity threshold values was noted for these more sensitive organisms, suggesting potential adverse ecological effects in aquatic environments. Affirmative evidence for this is lacking, however, since studies examining environmental occurrences of biocides vis-ą-vis the health and diversity of aquatic species have not yet been conducted. [source]


Relationship between biochemical biomarkers and pre-copulatory behaviour and mortality in Gammarus pulex following pulse-exposure to lambda-cyhalothrin

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2005
Lars-Henrik Heckmann
Abstract The impact of the pyrethroid lambda-cyhalothrin was studied in an in-stream mesocosm placed in a natural riffle of a Danish stream. Twice during summer 2002, the natural macroinvertebrate community was exposed in situ to a 30-min pulse of lambda-cyhalothrin. During exposure, nets caught macroinvertebrates in drift. Exposed and unexposed individuals of the amphipod Gammarus pulex (L) were transferred to aquaria in the laboratory and monitored for biochemical changes (ie biomarkers), pre-copulatory behaviour and mortality. Biochemical biomarkers were identified by screening extracts of exposed and unexposed G pulex using high-performance planar chromatography (HPPC). Biochemical biomarkers were detected 3 h after pulse-exposure, and one biomarker was persistent up to 7 days after exposure. Pre-copulatory behaviour (ie pair formation) was significantly impaired up to 5 days after exposure, and had not fully recovered at the end of the observation period. EC10(0.5 h) and EC50(0.5 h) values for pre-copulatory behaviour were 0.04 and 0.20 µg litre,1, respectively. Mortality was significant at 0.35 µg litre,1 with an LC50(0.5 h) of 5.69 µg litre,1. There was a significant relationship between two biomarkers and mortality. The study demonstrated that pulse-exposure at expected environmental concentrations can reduce local populations of G pulex, resulting in severe impact on populations with limited possibilities of re-colonisation. Copyright © 2005 Society of Chemical Industry [source]


An ecological risk assessment for spinosad use on cotton

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 1 2002
Cheryl B Cleveland
Abstract Spinosad is a reduced-risk insecticide with a novel mode of action that provides an alternative to older classes of insecticides such as organophosphates, carbamates and pyrethroids. A comprehensive ecological risk assessment for spinosad use in US cotton crops is presented within a framework of tiered levels of refinement following the guidelines of the US EPA for ecological risk assessments. Toxicity information for a variety of species is documented and utilized, environmental concentrations estimated, and risk characterizations in the form of risk quotients are quantified. Results indicate that spinosad use in cotton does not exceed the most conservative Tier I levels of concern (LOC) values for groundwater, mammals and birds or acute risk to aquatic organisms. Use of very conservative Tier I screening methods resulted in exceeding LOC values for chronic exposure for some aquatic organisms, thus prompting further refinement. When the exposure prediction was refined using less conservative, Tier II mechanistic environmental fate transport models to predict off-site transport and environmental concentrations, chronic risk was not predicted for these species. Spinosad is acutely toxic to bees under laboratory conditions, but toxicity of residue studies and field studies indicate that under actual use conditions the impact on bees is minimal. © 2001 Society of Chemical Industry [source]


Designing herbicide formulation characteristics to maximize efficacy and minimize rice injury in paddy environments

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 6 2001
Steven A Cryer
Abstract Mathematical descriptors, coupled with experimental observations, are used to quantify differential uptake of an experimental herbicide in Japonica and Indica rice (Oryza sativa, non-target) and barnyardgrass (Echinochloa crus-galli, target). Partitioning, degradation, plant uptake and metabolism are described using mass-balance conservation equations in the form of kinetic approximations. Estimated environmental concentrations, governed by the pesticide formulation, are described using superimposed analytical solutions for the one-dimensional diffusion equation in spherical coordinates and by a finite difference representation of the two-dimensional diffusion equation in Cartesian coordinates. Formulation attributes from granules include active ingredient release rates, particle sizes, pesticide loading, and granule spacing. The diffusion model for pesticide transport is coupled with the compartment model to follow the fate and transport of a pesticide from its initial application location to various environmental matrices of interest. Formulation effects, partitioning and degradation in the various environmental matrices, differential plant uptake and metabolism, and dose-response information for plants are accounted for. This novel model provides a mechanism for selecting formulation delivery systems that optimize specific attributes (such as weed control or the therapeutic index) for risk-assessment procedures. In this report we describe how this methodology was used to explore the factors affecting herbicide efficacy and to define an optimal release rate for a granule formulation. © 2001 Society of Chemical Industry [source]


Simultaneous determination of t,t -muconic, S -phenylmercapturic and S -benzylmercapturic acids in urine by a rapid and sensitive liquid chromatography/electrospray tandem mass spectrometry method

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2004
Anna Barbieri
We describe a rapid and sensitive high-performance liquid chromatography/electrospray tandem mass spectrometry (HPLC/ESI-MS/MS) method for simultaneous determination of the most relevant metabolites of benzene and toluene, t,t- muconic acid (t,t -MA), S -phenylmercapturic acid (S-PMA), and S -benzylmercapturic acid (S-BMA). Urine samples were purified before analysis by solid-phase microextraction (SPE) on SAX cartridges with 50,mg sorbent mass. The developed method fulfils all the standard requirements of precision and accuracy. Calibration curves were linear within the concentration range of the standards (0,80,,g/Lurine for t,t -MA, and 0,25,,g/Lurine for S-PMA and S-BMA), and had correlation coefficients ,0.997. Limits of detection were 6.0,,g/L for t,t -MA, 0.3,,g/L for S-PMA, and 0.4,,g/L for S-BMA. The method was used to determine t,t -MA, S-PMA and S-BMA levels in urine of 31 gasoline-station workers, with personal monitoring data obtained from radial symmetry passive diffusive samplers. In the context of mean work-shift exposures of 75.9,,g/m3 (range 9.4,220.2) for benzene and 331.9,,g/m3 (78.2,932.1) for toluene, metabolite concentrations in end-of-shift urine samples ranged from 23.5,275.3,,g/gcreatinine for t,t -MA, non-detectable to 0.9,,g/gcreatinine for S-PMA, and 3.8,74.8,,g/gcreatinine for S-BMA. No significant correlation was found between the environmental concentrations and urinary metabolites (p,>,0.05 for all cases); the ratios of benzene metabolites could be influenced by exposure levels and co-exposure to xylenes and toluene. The high throughput of this procedure should facilitate exploration of the metabolic effects of benzene-related co-exposure to toluene and alkylbenzenes in large populations of subjects exposed to gasoline. Copyright © 2004 John Wiley & Sons, Ltd. [source]