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Abstract Poisoning from pesticides is a global public health problem and accounts for nearly 300,000 deaths worldwide every year. Exposure to pesticides is inevitable; there are different modes through which humans get exposed to pesticides. The mode of exposure is an important factor as it also signifies the concentration of pesticides exposure. Pesticides are used extensively in agricultural and domestic settings. These chemicals are believed to cause many disorders in humans and wildlife. Research from past few decades has tried to answer the associated mechanism of action of pesticides in conjunction with their harmful effects. This perspective considers the past and present research in the field of pesticides and associated disorders. We have reviewed the most common diseases including cancer which are associated with pesticides. Pesticides have shown to be involved in the pathogenesis of Parkinson's and Alzheimer's diseases as well as various disorders of the respiratory and reproductive tracts. Oxidative stress caused by pesticides is an important mechanism through which many of the pesticides exert their harmful effects. Oxidative stress is known to cause DNA damage which in turn may cause malignancies and other disorders. Many pesticides have shown to modulate the gene expression at the level of non-coding RNAs, histone deacetylases, DNA methylation patterns suggesting their role in epigenetics. [ABSTRACT FROM AUTHOR]

Abstract The Black Kite (Milvus migrans) has a limited distribution within Taiwan due to a dramatic population decrease during the late 20th century. Prompted by some poisoning incidents of Black Kites and other farmland birds, we hypothesized that poisoning may be an underreported yet important threat. Thus, we created a citizen-science Facebook group in October 2014 in order to receive more information about possible poisoning incidents. By September 2016, we had received reports of 4753 dead birds in 213 separate poisoning incidents in agricultural areas. The types of fields most often associated with poisoning incidents were direct-seeded rice (Oryza sativa), rice that was soon to be harvested, and red beans (Vigna angularis). We tested tissues from 29 dead small birds for pesticide residues. Twenty-eight birds contained carbofuran, and one bird contained terbufos, both highly toxic pesticides. Furthermore, of seven dead Black Kites tested from 2010 to 2016, four contained carbofuran, and three contained second-generation anticoagulant rodenticides. After interviewing farmers and reviewing older agricultural literature, we concluded that most of these incidents represented intentional poisonings by farmers attempting to control avian pests and rats (mostly Bandicota indica and Rattus spp.). We suggest that the Black Kites were likely the victims of inadvertent secondary poisoning incidents. The dramatic decrease of the Black Kite in the 1980s coincided with the rapid increase in the area planted with direct-seeded rice and the widespread use of carbofuran and rodenticides. The recent decreased use of these pesticides due to restrictions has coincided with the recent slow recovery of the Black Kite population. Therefore we initiated public awareness campaigns, and the Taiwanese government has adjusted some pesticide-use policies. [ABSTRACT FROM AUTHOR]

1. There is growing concern that declines in some managed and wild bee pollinator populations threaten biodiversity, the functioning of vital ecological processes and sustainable food production on a global scale. 2. In recent years, there has been increasing evidence that sublethal exposure to the neurotoxic class of insecticides (neonicotinoids) can undermine pollinator immunocompetence and amplify the effects of diseases, which have been suspected to be one of the drivers of pollinator declines. However, exactly how neonicotinoids might inhibit pollinator immunity remains elusive. 3. Here, we put forward a mechanistic framework to explain the effects of neurotoxic pesticides on insect immunocompetence. We propose that there is a close ontogenetic connection between the cellular arm (haemocytes) of the insect immune and nervous systems and that this connection makes the immune system of pollinators and other insects inherently susceptible to interference by neurotoxins such as neonicotinoids at sublethal doses. 4. Investigation of this connection is urgently needed to confirm the validity of this framework and develop a clear, mechanistically informed understanding of the interplay between neonicotinoids and disease ecology in pollinators. This in turn may enable us to develop strategies to mitigate impacts of neurotoxins on pollinators and/or enhance their impacts on pests. [ABSTRACT FROM AUTHOR]

The presence of honey bee in the environment has a significant impact on global agricultural production. While searching for pollen and nectar, the bee is often exposed to several contaminants such as plant protection products. The aim of this study was to assess the impact of selected pesticides from various groups (fungicides, herbicides, insecticides) on the way the bees harvested food as well as on their behavior, survival rate and the concentration of certain elements in the organisms of bee. The concentration possibly similar to this applied in agriculture and recommended by the manufacturers, were used. The research material was analyzed in terms of the presence of trace elements (manganese, copper, iron, nickel, zinc, lead, cadmium) of different toxicity. The study clearly indicates that selected pesticides used for the purpose of plant protection and plant cultivation may adversely on bees' behavior and accumulation of trace elements in their body. Among the tested pesticides particular attention should be paid to fungicides that are not commonly tested for their effects on the honey organ. In own studies showed, their effect significantly changed the content of copper and negatively affected the survival of the bees. [ABSTRACT FROM AUTHOR]

Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weekly water samples, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per sample and 54 detected per site. In a screening-level assessment using aquatic-life benchmarks and the Pesticide Toxicity Index (PTI), potential effects on fish were unlikely in most streams. For invertebrates, potential chronic toxicity was predicted in 53% of streams, punctuated in 12% of streams by acutely toxic exposures. For aquatic plants, acute but likely reversible effects on biomass were predicted in 75% of streams, with potential longer-term effects on plant communities in 9% of streams. Relatively few pesticides in water—atrazine, acetochlor, metolachlor, imidacloprid, fipronil, organophosphate insecticides, and carbendazim—were predicted to be major contributors to potential toxicity. Agricultural streams had the highest potential for effects on plants, especially in May–June, corresponding to high spring-flush herbicide concentrations. Urban streams had higher detection frequencies and concentrations of insecticides and most fungicides than in agricultural streams, and higher potential for invertebrate toxicity, which peaked during July–August. Toxicity-screening predictions for invertebrates were supported by quantile regressions showing significant associations for the Benthic Invertebrate-PTI and imidacloprid concentrations with invertebrate community metrics for MSQA streams, and by mesocosm toxicity testing with imidacloprid showing effects on invertebrate communities at environmentally relevant concentrations. This study documents the most complex pesticide mixtures yet reported in discrete water samples in the U.S. and, using multiple lines of evidence, predicts that pesticides were potentially toxic to nontarget aquatic life in about half of the sampled streams. [ABSTRACT FROM AUTHOR]

BACKGROUND Although considered as a safe pesticide application method, treated seeds can pose environmental risks when abraded pesticide-laden seed particles are expelled during sowing. This dust drift risk is clearly linked with seed coating quality. Seed coating quality is traditionally assessed with Heubach dust meters, and guidelines are established in terms of the 'Heubach value'. This technique may, however, not take all drift-sensitive particles into account. In this study, results of the Heubach test are compared with two alternative set-ups: mechanical sieving and the individual sowing element. RESULTS The abrasion potential assessed with the Heubach dust meter was much lower than the total dust fraction generated by mechanical sieving and the individual sowing element. The amount of dust produced and the dust particle size distribution of both the other techniques were comparable. CONCLUSION It looks as if the Heubach dust meter underestimates the risk of dust drift. Using one of the alternative methods might be a more appropriate way to assess the abrasion potential of seeds. Given the low investment cost required, mechanical sieving seems to be a good approach for non-specialised labs. The individual sowing element set-up is the most realistic simulation of in-field dust drift generation but requires a higher initial investment. Therefore, this set-up is most suitable for specialised labs and is recommended for further research in this area. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The registration of pesticides follows guidance published by the European Food Safety Authority (EFSA). As a default, the EFSA guidance document on risk assessment for birds and mammals assumes that animals feed exclusively on pesticide-treated fields. However, the guidance document suggests refining the risk via the proportion of food animals obtain from a treated field or specific crop (expressed via the portion of diet obtained from a treated area [PT value]). The EFSA guidance equalizes the portion of food taken from a treated area per day with the portion of time spent potentially foraging over the course of a day within this area. Therefore, radiotracking is commonly used to gather species-, crop-, and season-specific PT data, and radio telemetry of continuously tracked farmland species can deliver individual PT values for a given day, crop, and species. In the present study the authors introduce a way of calculating long-term PT values based on empirically recorded data via telemetry field studies for the most appropriate use in wildlife risk assessment of pesticides. The novel aspect of the proposal is that the authors follow the prerequisite given by EFSA to cover the long-term risk by introducing 21-d PT values that aim to cover both intra- and inter-individual variability of foraging focal farmland species in cropped habitats. Currently, the intra-individual variability is not taken into account for PT calculations. The authors demonstrate this approach and discuss EFSA guidance input requirements for PT values recorded in field studies, based on a PT field study conducted with woodpigeons ( Columba palumbus) radiotracked in an agricultural landscape in the United Kingdom. The results indicate that a 21-d PT value considering intra-individual variability gives a more appropriate PT value for long-term risk assessments. Environ Toxicol Chem 2017;36:1270-1277. © 2016 SETAC [ABSTRACT FROM AUTHOR]

Amitraz, an acaricide used to treat Varroa destructor Anderson & Trueman, is one of the most commonly detected pesticides in honey bee (Apis mellifera L.) hives. Acaricides sometimes negatively impact honey bee cognition, but potential effects of amitraz on honey bee learning have been rarely studied. We topically exposed foragers to 95th percentile field-relevant levels of amitraz and, 24 h later, tested the ability of bees to associate a sucrose reward with a conditioned odor (learning response) using the proboscis extension response (PER). We then tested the ability of the bees to retain this memory 1 h and 2 h post-conditioning. Because amitraz is thought to affect octopamine metabolism in honey bees, and because octopamine is directly related to honey bee learning and memory, we also examined effects of exposure to amitraz on octopamine levels in honey bee hemolymph. We found that acute exposure to 95th percentile doses of amitraz had no impact on honey bee learning or short-term memory as measured by PER. Concentrations of octopamine in hemolymph from our low amitraz treatment were 1.4-fold higher than control levels, but other treatments had no effect. Our results from worst-case acute exposure experiments with worker bees in the laboratory suggest that typical fieldrelevant (within hive) exposures to amitraz probably have little effect on honey bee learning and memory. [ABSTRACT FROM AUTHOR]

This review aims to provide an update on our current knowledge of the various effects of pesticide cocktails. We have collected data from studies conducted in mammalian models in vitro and in vivo that was published between 2000 and 2014. All ecotoxicological studies were voluntarily excluded. Cocktail effects were classified according to how they had been classified by each author. The frequency of the various cocktail effects and the classes and chemical families of pesticides involved in the observed effects were assessed. When focusing on the function of pesticides (i.e. herbicide, insecticide or fungicide), 46% of the mixtures contained insecticides alone, 15% fungicides alone, and 4.5% herbicides alone. Mixtures with effects associated with neurotoxicity were mainly composed of insecticides, and most studies on the effects of fungicide mixtures (90%) were associated with effects on endocrine regulation and/or reproduction. Dose addition was observed with each kind of mixture except herbicide combinations. In contrast, synergic interactions or greater-than-additive effects were mainly reported for insecticide mixtures. There were few examples of potentiating and antagonistic interactions. We have identified chemical families of compounds specifically involved in synergy, addition, potentiation and antagonism, and those that do not interact when combined. The chemical families identified as being involved in synergy are in agreement with data from another recently published compilation of ecotoxicological studies. For most mixtures investigated, further validation data is still needed from experiments using other compounds and other experimental models but this update provides useful information to help in human health risk assessments. [ABSTRACT FROM AUTHOR]

Co-occurrence of pesticides such as synthetic pyrethroids and metals in aquatic ecosystems raises concerns over their combined ecological effects. Cypermethrin, 1 of the top 5 synthetic pyrethroids in use, has been extensively detected in surface water. Cadmium (Cd) has been recognized as 1 of the most toxic metals and is a common contaminant in the aquatic system. However, little information is available regarding their joint toxicity. In the present study, combined toxicity of cypermethrin and Cd and the underlying mechanisms were investigated. Zebrafish embryos and adults were exposed to the individual contaminant or binary mixtures. Co-exposure to cypermethrin and Cd produced synergistic effects on the occurrence of crooked body, pericardial edema, and noninflation of swim bladder. The addition of Cd significantly potentiated cypermethrin-induced spasms and caused more oxidative stress in zebrafish larvae. Cypermethrin-mediated induction of transcription levels and catalytic activities of cytochrome P450 (CYP) enzyme were significantly down-regulated by Cd in both zebrafish larvae and adults. Chemical analytical data showed that in vitro elimination of cypermethrin by CYP1A1 was inhibited by Cd. The addition of Cd caused an elevation of in vivo cypermethrin residue levels in the mixture-exposed adult zebrafish. These results suggest that the enhanced toxicity of cypermethrin in the presence of Cd results from the inhibitory effects of Cd on CYP-mediated biotransformation of this pesticide. The authors' findings provide a deeper understanding of the mechanistic basis accounting for the joint toxicity of cypermethrin and Cd. Environ Toxicol Chem 2016;35:435-445. © 2015 SETAC [ABSTRACT FROM AUTHOR]

This article discusses the shrinking population of monarch butterflies. The authors comment on the impact of extreme weather, pesticides, habitat loss, and disease, on their populations, with a particular focus on their migration of thousands of miles. Studies by the U.S. Fish and Wildlife Service and organizations such as the World Wildlife Fund are explored.

ABSTRACT The toxic effects of Gusathion (GUS), which is a commercial organophosphate (OP) pesticide, and also its active ingredient, azinphos methyl (AzM), are evaluated comparatively with in vitro and in vivo studies. Initially, the 96-h LC50 values of AzM and GUS were estimated for two different life stages of Xenopus laevis, embryos, and tadpoles. The actual AzM concentrations in exposure media were monitored by high-performance liquid chromatography. Also, the sub-lethal effects of these compounds to tadpoles were determined 24 h later at exposure concentrations of 0.1 and 1 mg/L using selected biomarker enzymes such as acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione S-transferase (GST), glutathione reductase, lactate dehydrogenase, and aspartate aminotrasferase. Differences in AChE inhibition capacities of AzM and GUS were evaluated under in vitro conditions between frogs and fish in the second part of this study. The AChE activities in a pure electrical eel AChE solution and in brain homogenates of adult Cyprinus carpio, Pelophylax ridibundus, and X. laevis were assayed after in vitro exposure to 0.05, 0.5, 5, and 50 mg/L concentrations of AzM and GUS. According to in vivo studies AChE, CaE and GST are important biomarkers of the effect of OP exposure while CaE may be more effective in short-term, low-concentration exposures. The results of in vitro studies showed that amphibian brain AChEs were relatively more resistant to OP exposure than fish AChEs. The resistance may be the cause of the lower toxicity/lethality of OP compounds to amphibians than to fish. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1091-1101, 2015. [ABSTRACT FROM AUTHOR]

ABSTRACT It is known that exposure to organophosphorus pesticides (OP) including phoxim can produce oxidative stress, neurotoxicity, and greatly attenuate cocooning rate in the silkworm, Bombyx mori. Cerium treatment has been demonstrated to relieve phoxim-induced toxicity in B. mori; however, very little is known about the molecular mechanisms of silk gland injury due to OP exposure and protection of gland damage due to cerium pretreatment. The aim of this study was to evaluate silk gland damage and its molecular mechanisms in phoxim-induced silkworm toxicity and the protective mechanisms of cerium following exposure to phoxim. The results showed that phoxim exposure resulted in severe gland damage, reductions in protein synthesis and the cocooning rate of silkworms. Cerium (Ce) attenuated gland damage caused by phoxim, promoted protein synthesis, increased the antioxidant capacity of the gland and increased the cocooning rate of B. mori. Furthermore, digital gene expression data suggested that phoxim exposure led to significant up-regulation of 714 genes and down-regulation of 120 genes. Of these genes, 122 were related to protein metabolism, specifically, the down-regulated Ser2, Ser3, Fib-L, P25, and CYP450. Ce pretreatment resulted in up-regulation of 162 genes, and down-regulation of 141 genes, importantly, Ser2, Ser3, Fib-L, P25, and CYP333B8 were up-regulated. Treatment with CeCl3 + phoxim resulted in higher levels of Fib-L, P25, Ser2, Ser3, CAT, TPx, and CYP333B8 expression in the silk gland of silkworms. These findings indicated that Ce increased cocooning rate via the promotion of silk protein synthesis-related gene expression in the gland under phoxim-induced toxicity. These findings may expand the application of rare earths in sericulture. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1102-1111, 2015. [ABSTRACT FROM AUTHOR]

In many regions of the world, organophosphorus (OP) and carbamate (CM) pesticides are used to poison wildlife thought to be competing with human activities (e.g. hunting). Vultures may be secondarily poisoned or directly targeted, e.g. for muti or traditional medicine. Some OPs and CMs are so acutely toxic that animals will die with poisoned material still in their mouths – un-swallowed, before traces may have spread to other parts of the body. Even when death is more prolonged, the tissues in which residues have accumulated may deteriorate before the carcass is discovered, minimizing the chances of recovering viable samples for toxicological analyses that would conclusively identify poisoning as the cause of death. With all these factors in mind, we investigated the feasibility of detecting OP and CM pesticides in the oral cavity, with emphasis on the tongue and palate. A total of 60 degraded carcasses (n = 28 avian and 32 mammalian) recovered from various scenes of wildlife crime in Andalucía, southern Spain, where poisoning was suspected, were submitted to the Center for Analysis and Diagnosis of Wildlife in Málaga for necropsy and toxicological analyses. Of these, 20 and 24 avian and mammalian tongues, respectively, could be recovered for analysis. Separately, the palate from one degraded Cinereous Vulture Aegypius monachus carcass was also opportunistically retrieved and analyzed following an incident of vulture mass-mortality in which nine Griffon Vultures Gyps fulvus also perished. Residues or presence of OPs and CMs were detected in one avian tongue (analyzed with food from the mouth) and four mammalian tongues. Our findings suggest avian tongues alone are not optimal, but canid tongues and those of larger mammals may lend themselves well to analysis. Detection of the OP chlorfenvinphos (3.39 mg/kg) in the Cinereous Vulture palate (the only part of the carcass in which residues were detected) indicates this is a promising sample. To our knowledge, this represents the first time that OP and CM pesticides have been detected in tongue and palate samples. We recommend further exploration of oral cavity samples, especially within the context of the risk that residues therein may pose to human health. [ABSTRACT FROM AUTHOR]

For more than 20 years, conservationists have agreed that amphibian populations around the world are declining. Results obtained through laboratory or mesocosm studies and measurement of contaminant concentrations in areas experiencing declines have supported a role of contaminants in these declines. The current study examines the effects of contaminant exposure to amphibians in situ in areas actually experiencing declines. Early larval Pseudacris regilla were translocated among Lassen Volcanic, Yosemite and Sequoia National Parks, California, USA and caged in wetlands in 2001 and 2002 until metamorphosis. Twenty contaminants were identified in tadpoles with an average of 1.3-5.9 (maximum = 10) contaminants per animal. Sequoia National Park, which had the greatest variety and concentrations of contaminants in 2001, also had tadpoles that experienced the greatest mortality, slowest developmental rates and lowest cholinesterase activities. Yosemite and Sequoia tadpoles and metamorphs had greater genotoxicity than those in Lassen during 2001, as determined by flow cytometry. In 2001 tadpoles at Yosemite had a significantly higher rate of malformations, characterized as hemimelia (shortened femurs), than those at the other two parks but no significant differences were observed in 2002. Fewer differences in contaminant types and concentrations existed among parks during 2002 compared to 2001. In 2002 Sequoia tadpoles had higher mortality and slower developmental rates but there was no difference among parks in cholinesterase activities. Although concentrations of most contaminants were below known lethal concentrations, simultaneous exposure to multiple chemicals and other stressors may have resulted in lethal and sublethal effects. [ABSTRACT FROM AUTHOR]

This study investigated the effects of the first generation anticoagulant rodenticide chlorophacinone and the second generation rodenticide bromadiolone on the population and breeding performances of barn owls at oil palm plantations. Three treatment plots were established: one baited with chlorophacinone, one with bromadiolone, and the third kept rodenticide-free. Four rat-baiting campaigns which coincided with barn owl breeding season were carried in the rodenticide-treated plots. The occupancy rate of nest boxes, clutch size, brood size and fledging rates of the barn owls in each plot were monitored weekly throughout the study. Freshly regurgitated pellets from barn owls were collected from all occupied nest boxes at weekly intervals during the development of nestlings in each breeding season. The results show that the occupancy rate of the nest boxes was significantly higher in the rodenticide-free area compared with both rodenticide-treated areas. Similarly, the breeding performances, such as clutch size, brood size and fledging success, were higher in the rodenticide-free area compared with the rodenticide-treated areas. Results of high performance liquid chromatography (HPLC) analysis showed that 20.56% (mean residue: 1 .335 ± 0.073 lg/g) and 28.89% (mean residue: 0.777 ± 0.032 lg/g) of the collected regurgitated pellet samples from the rodenticide-treated areas contained bromadiolone and chlorophacinone residue, respectively. The mean brood size and fledging success of the barn owls showed a strong negative correlation with the mean concentration of rodenticide residues present in the regurgitated pellets and with the percentages of pellets detected having such residues (R2 k 0.44, P < 0.05). Similarly, the mean clutch size of barn owls was negatively correlated with the mean concentration of rodenticide residues and with the percentages of pellets detected with these residues. However, the correlation was not significantly different (R2 k 0.34, P > 0.05). In general, the higher the amount of residues detected, the lower the breeding performance parameters measured in this study [ABSTRACT FROM AUTHOR]

Out of thin air: In this Editorial, the Guest Editors introduce a Special Issue on Carbon Dioxide Conversion Catalysis, discuss its importance in modern chemical processes, and highlight a few examples of its use in industry, such as the synthesis of cyclic carbonates and the conversion of CO2 into fuels. [ABSTRACT FROM AUTHOR]

Pesticide use results in the widespread distribution of chemical contaminants, which necessites regulatory agencies to assess the risks to environmental and human health. However, risk assessment is compromised when relatively few studies are used to determine impacts, particularly if most of the data used in an assessment are produced by a pesticide's manufacturer, which constitutes a conflict of interest. Here, we present the shortcomings of the US Environmental Protection Agency's pesticide risk assessment process, using the recent reassessment of atrazine's impacts on amphibians as an example. We then offer solutions to improve the risk assessment process, which would reduce the potential for and perception of bias in a process that is crucial for environmental and human health. [ABSTRACT FROM PUBLISHER]

Poisoning with agricultural chemicals is a major threat for wildlife all over the world. We have developed and validated an analytical scheme aimed to the identification and quantification of a wide range of pesticides in fresh liver from wildlife specimens that are routinely delivered to the forensic laboratories for toxicological investigation. The proposed method is comprised of a general solid–liquid extraction followed by purification steps and three complementary liquid or gas chromatographic analyses with triple quadrupole mass spectrometry detection. The developed methodology allows for the determination of 117 highly toxic pesticides in a variety of samples from wildlife poisoning incidents. The validity of the method has been demonstrated in samples from 98 real cases submitted to our laboratory between 2010 and 2012. This method allowed the identification and quantification of poison in 78 of 94 fresh liver samples from wild animals and was successfully used for the identification of pesticides in 35 of 46 non-liver samples. Therefore, the extraction and cleanup method with minor modifications and the potency of triple quadrupole mass spectrometry allow this method to be used to simultaneously detect and quantify or semi-quantify a majority of the most toxic pesticides in a variety of complex and degraded matrices. [ABSTRACT FROM AUTHOR]

It is increasingly recognized that a sustainable future for agriculture must build on ecosystem services. Pollination is an important ecosystem service in all agroecosystems. In much of Africa the main challenge is conserving pollinator biodiversity in traditionally "ecologically-intensive" agroecosystems that are changing to meet different demands for food security and poverty alleviation, rather than safeguarding pollination in transition from conventional agricultural systems, with a high reliance on purchased inputs, to "ecologically-intensive" agroecosystems using natural inputs provided by biodiversity. Priority issues for research and development in pollination services in Africa include, inter alia: quantification and documentation of pollination deficits and finding measures to address these; socio-economic valuation of pollinator-friendly practices; assessment of lethal and sub-lethal effects of farming methods, such as pesticide use, on crop pollinators; identification of habitat management practices that enhance synergies between pollinator lifecycles and crop growing patterns; and policy analysis in relation to drivers and trends in pollination services and management. [ABSTRACT FROM AUTHOR]

The use of anticoagulants has increased in recent times as a method for controlling rodent populations. However, this increased use also provokes accidental and intentional ingestion for both animals and humans, triggering poisoning of non-target organisms. In the present report, a clinical case of secondary-poisoning of birds with anticoagulant rodenticides, which took place after a general rodenticide treatment in an Ornithological Zoological Park, is described. Three birds died as a result and samples were submitted to the Veterinary Hospital in Lugo (Galicia, NW Spain). After necropsy, samples of the birds, together with molluscs and faeces, were submitted to the Toxicology Unit of Caceres (Extremadura, W Spain) in order to detect possible chemicals. Results from HPLC analyses revealed the presence of the rodenticides difenacoum and brodifacoum. The present report shows that the risk of secondary exposure resulting from the scavenging of molluscs is likely to be significant. The potential routes of uptake by invertebrates include the consumption of rodent faeces, rodent carcases, the ingestion of soil-bound residues, and the direct consumption of poison baits. [ABSTRACT FROM AUTHOR]

Pesticides are receiving increasing attention as potential causes of amphibian declines, acting singly or in combination with other stressors, but limited information is available on the accumulation of current-use pesticides in tissue. The authors examined potential exposure and accumulation of currently used pesticides in pond-breeding frogs ( Pseudacris regilla) collected from 7 high elevations sites in northern California. All sites sampled are located downwind of California's highly agricultural Central Valley and receive inputs of pesticides through precipitation and/or dry deposition. Whole frog tissue, water, and sediment were analyzed for more than 90 current-use pesticides and pesticide degradates using gas chromatography-mass spectrometry. Two fungicides, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected pesticides in tissue samples. Median pesticide concentration ranged from 13 µg/kg to 235 µg/kg wet weight. Tebuconazole and pyraclostrobin were the only 2 compounds observed frequently in frog tissue and sediment. Significant spatial differences in tissue concentration were observed, which corresponded to pesticide use in the upwind counties. Data generated indicated that amphibians residing in remote locations are exposed to and capable of accumulating current-use pesticides. A comparison of P. regilla tissue concentrations with water and sediment data indicated that the frogs are accumulating pesticides and are potentially a more reliable indicator of exposure to this group of pesticides than either water or sediment. Environ Toxicol Chem 2013;32:2026-2034. © 2013 SETAC [ABSTRACT FROM AUTHOR]

The effect of low-dose dichlorodiphenyltrichloroethane on the function of the immune system is a serious problem because of wide use of this pollutant. We studied the morphological and functional changes in the thymus of rats receiving low-dose dichlorodiphenyltrichloroethane for 6 and 10 weeks. Histological studies detected changes characterized by lymphocyte and reticuloepitheliocyte death, progressing with increase of dichlorodiphenyltrichloroethane dose, and a decrease of the thymocyte proliferative activity. The results of comparative analysis of changes in the thymuses of rats in experimental and control groups during different periods of the study indicated that low-dose dichlorodiphenyltrichloroethane promoted earlier onset of age-specific involution and caused a dose-dependent acceleration of these changes. [ABSTRACT FROM AUTHOR]

The aim of the present study is to find the toxic effect of fenvalerate, a synthetic pyrethroid pesticide on the gill of a teleost cat fish, Heteropneustes fossilis pesticide after its characterization by Scanning Electron Microscopy (SEM). Three different sublethal doses of fenvalerate dissolved in acetone were used to find the damage on the gills. Fenvalerate found toxic to all the doses given to the test fish. [ABSTRACT FROM AUTHOR]

To determine possible human and environmental health risks, organochlorine pesticide residues were determined in vegetables grown in floodplains along the Ouémé River near Lowé in Bénin. Testing of vegetables found 13 pesticides with ΣDDT, α-endosulfan, Σdrin, and lindane being most important. The same pesticides were also detected in plants eaten by bovine cattle, sheep, and herbivorous fish. Human pesticide intake by vegetable consumption was compared with tolerable daily intake (TDI) values reported by the World Health Organization. Pesticide intake by fish consumption was estimated from residue levels in whole fish collected from the Ouémé River in 2004 and reported earlier. Fish consumption does not pose a risk for human health, but consuming vegetables that contain pesticide residues may lead to exceedance of TDI values. Based on these findings, concerns are warranted, and more work is needed to understand the full exposure profile for the local population. [ABSTRACT FROM AUTHOR]

Concentrations of chlorinated hydrocarbons and their derivatives in the organs of spotted seals captured in the Sea of Japan are determined. Isomers of hexachlorocyclohexane (HCCH) and metabolites of dichlorodiphenyltrihlormetilmetan (DDT) are detected in all the studied animals in all the samples, but the highest concentrations are found in adipose tissue, which is a peculiar depot in which toxins are accumulated. Substantial differences in the extent of damage by toxins are discovered in seals of different populations, which is due to different intensities in the action of technogenic load on separate water areas. The level of accumulation of lipophilic xenobiotics in the tissues and organs of spotted seals of the Sea of Japan, particularly from the Peter the Great Bay (PGB), turn out to be very high (several orders of magnitude higher than that in spotted seals from the Tatar Strait and the coastal region of Hokkaido). Such a high level of chlorinated organic pesticides (COPs) has not yet been detected in any Pinnipeds inhabiting the northern part of the Pacific Ocean. The results of our studies allow us to state that COPs have been present in the ecosystem are the Sea of Japan for a long time and have undergone substantial transformation. [ABSTRACT FROM AUTHOR]

Intensification of farming practices is a key factor in population declines of many species, including aerial insectivores. Of these species, Tree Swallow populations have been declining rapidly in Canada, likely in response to increased pesticide use (depleting insect prey) and destruction of marginal habitats (limiting cavity-nesting opportunities). Agricultural intensification may however be favourable to other species. House Sparrows for instance could benefit from abundant nesting sites (farm buildings) and food resources (grains) in intensive landscapes. Competition for nesting sites between these two species has been observed, and could be another factor in the decline of Tree Swallows. In a 400 nest-box study system embedded along a gradient of agricultural intensification of Southern Québec, Canada, we first assessed effects of intensification on abundance of House Sparrows by analysing 5,200 min of point counts. From these results, we modeled influence of competition and habitat on Tree Swallow nest site selection. Density of sparrows and proximity to buildings reduced the nest-box occupancy of swallows. Therefore, agricultural intensification had opposite influences on these two species, directly affecting House Sparrow abundance, but indirectly exacerbating competition pressure on swallows through competitor abundance. These results provide evidence of interspecific competition between these species, highlighting the indirect role of anthropogenic alterations on agro-ecosytems and illustrating a landscape-mediated avian competition pressure that has, to our knowledge, never been documented in farmscapes. [ABSTRACT FROM AUTHOR]

Risk assessment investigates the potential impacts of chemicals on non-target organisms. To assess the risk, ecotoxicologists study the responses of a panel of species to different substance exposure. Among the different parameters used to select indicator species (i.e. focal species), their frequency of occurrence is considered as the key parameter. Although species occurrence within a given habitat is easy to determine, we argue that it does not totally reflect the dependence of a species on a given habitat or its potential exposure to chemicals. In this study, we combined the occurrence of species with their habitat-specificity to identify focal species for risk assessment in cereals. We showed that ranking species by occurrence or by habitat-specificity produced different results, with generalist species ranking high in the occurrence list, and species with specialised habitats ranking high in the abundance list. Integrating frequency and abundance of species into one single indicator (the "Indicator Value") allows us to rank species with specialised habitats as high as generalist species in the top rank species list. Although habitat-specificity is an ecologically meaningful concept, it is largely overlooked in eco-toxicological risk assessment, despite the fact that specialists are good indicators of various environmental pressures. This method could be used extensively at different scales and could contribute to studies on risk assessment issue by (re)introducing ecological and population-level concepts and opening up new trait-based approaches. [ABSTRACT FROM AUTHOR]

Competition is a ubiquitous factor in natural populations and has been reported to alter the ecological impact of xenobiotics. We investigated conditions that mirror the natural variation of environmental factors. For this, different treatments were applied to 96 outdoor pond microcosms by shading the ponds and harvesting the communities. Then, the effect of esfenvalerate (0.03, 0.3, and 3 μg/L) on populations of Daphnia spp. was investigated. The pesticide effect and the sensitivity of Daphnia spp. in the context of a zooplankton community was increased by intraspecific competition 11 days after contamination. This relationship was most pronounced at 0.03 and 0.3 μg/L esfenvalerate, which were the concentrations that led to partial mortality. In contrast, interspecific interaction did not significantly alter the effect of the toxicant on Daphnia spp. Modelled concentration-response curves showed that the negative effects of the pesticide differed by a factor of up to 100 depending on the strength of intraspecific competition. In addition, a wider range of concentrations led to negative effects at high levels of intraspecific competition than at low levels. We argue that increased intraspecific competition reduces the availability of resources at the individual level and thereby increases the effect of contaminants. This knowledge about the interaction between competition and the response to toxicants is important in assessing the effects of these factors under field conditions. [ABSTRACT FROM AUTHOR]

Basic research on the insect immune response has progressed dramatically within the last two decades, showing that immunity is one of the most effective defenses against foreign invaders. As such, it is important to understand the causes of variation in this response. Here, we investigate the effects of pesticides used in Costa Rican banana plantations on the immune response of the lepidopteran larva, Caligo memnon (Brassolinae). In addition, we performed a parasitism survey of the banana plantations and surrounding forests to provide a broader assessment of pesticide effects on parasitoid populations. All caterpillars for the immune assay were collected from two banana plantations and brought to La Selva Biology Station for immune challenge. Individuals were fed leaves from the plantations (pesticide) or leaves from La Selva (pesticide-free), then immune challenged with injected sephadex beads. We found that individuals feeding on pesticide leaves had significantly lower bead melanization compared to individuals feeding on pesticide-free leaves. Nonetheless, the parasitism survey showed that caterpillars from the banana plantations had lower parasitism rates compared to caterpillars from the La Selva forest. This study adds to the growing body of evidence documenting negative effects of pesticides on the insect immune response and on adult parasitoids, and underscores the need for more research at the intersection between ecological entomology and immunology. [ABSTRACT FROM AUTHOR]

Rachel Carson, in Silent Spring, pointed out that modern pesticides caused serious toxic effects. Since 1962, the book has had a considerable impact, but in the same period of time, the production of organic chemicals has increased more than tenfold. Humans and wildlife are exposed to a wide range of chemicals including pesticides, but also industrial chemicals such as plastic softeners, flame retardants, impregnating agents, surfactants, colorants, dyestuffs and various chemicals in food packaging. Problematic chemicals are regulated in the EU and worldwide. However, often a ban on a chemical leads to substitution by chemicals with a similar performance, but also similar unwanted properties. The potential of Green Chemistry to reshape the universe of chemical products has not yet been exploited. [ABSTRACT FROM AUTHOR]

Rachel Carson's Silent Spring ignited a controversy over synthetic chemical residues, which illustrates several important elements of gender in Carson's legacy. First, Carson's approaches in Silent Spring challenged traditional gender stereotypes. Second, the reception to Silent Spring reveals assumptions about gender that influenced the ways in which Carson's critics understood human and environmental health. Finally, endocrine disrupting chemicals had the potential to disrupt sexual differentiation in exposed animals. Two of Carson's core insights - the transgenerational effects of synthetic chemicals and the ecological context of human health - have continuing relevance for understanding the environmental and human health effects of endocrine disrupting chemicals. [ABSTRACT FROM AUTHOR]

In her book Silent Spring, Rachel Carson describes the catastrophic effects of the indiscriminate use of pesticides in the 1940s and 1950s. These substances, most of them insecticides, have since been designated as persistent organic pollutants and are regulated nationally and internationally. They have subsequently been replaced by less persistent yet highly toxic compounds. The experience gained in those decades triggered environmental regulation and risk assessment schemes. The ecotoxicological tests required for risk assessment greatly advanced the development of new concepts and tools in this field. Today, we are no longer faced with disastrous poisonings such as those described in Silent Spring. Nevertheless, the same compounds are still present in the environment adding to the increasing number of chemicals organisms must cope with. Many ecotoxicological questions remain to be solved and new ones have emerged regarding, eg., the effects of nanomaterials, the phenomenon of bee colony collapse disorder, and the consequences of climate change. [ABSTRACT FROM AUTHOR]

BACKGROUND: Honey bees are important pollinators of both crops and wild plants. Pesticide regimes that threaten their sustainability should therefore be assessed. As an example, evidence that the agricultural use of neonicotinoid pesticides is a cause of the recently observed declines in honey bees is examined. The aim is to define exacting demographic conditions for a detrimental factor to precipitate a population decline, and Hill's epidemiological 'causality criteria' are employed as a structured process for making an expert judgement about the proposition that trace dietary neonicotinoids in nectar and pollen cause population declines in honey bees. RESULTS: In spite of the absence of decisive experimental results, the analysis shows that, while the proposition is a substantially justified conjecture in the context of current knowledge, it is also substantially contraindicated by a wide variety of circumstantial epidemiological evidence. CONCLUSION:It is concluded that dietary neonicotinoids cannot be implicated in honey bee declines, but this position is provisional because important gaps remain in current knowledge. Avenues for further investigations to resolve this longstanding uncertainty are therefore identified. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The article discusses the history of regulation of the pesticide carbofuran in North America after its introduction in the 1960s. Evidence of its non-target effects on wildlife and birds, environmental persistence, and human health risks ultimately led the U.S. Environmental Protection Agency (EPA) and the Canadian Pest Management Regulatory Agency (PMRA) to ban the chemical in 2010. Reports of illegal carbofuran use against wildlife in Kenya, India, and Europe are reviewed.

Abstract: A growing number of studies now indicate that perfluorinated compounds (PFCs) are globally distributed in the environment. Their widespread distribution and presence in remote locations has led to questions about the importance of atmospheric and oceanic transport. Describing their distribution in surface soils is also an essential but neglected element in developing a comprehensive understanding of their occurrence in the environment. Soils are the critical link between global atmospheric and hydrologic processes where both local and distant contaminants can accumulate and be released into aquatic and terrestrial communities. Because PFC concentrations in soils will influence ground and surface water, wildlife, and crops, methods to accurately measure PFCs in soil are clearly needed. To help answer this need, we developed a method for the analysis of nine perfluorinated carboxylic acids and four perfluorinated sulfonic acids in soil. Samples from six nations (n =10 per nation) were analyzed by LC-MS/MS to demonstrate the method performance parameters and to make preliminary observations about the occurrence of the PFCs in soils in different parts of the world. The resulting method shows acceptable performance characteristics for the target compounds in most soils while documenting the widespread occurrence of PFCs in surface soils. [Copyright &y& Elsevier]

Eggs from aplomado falcons (Falco femoralis septentrionalis) nesting in Chihuahua and Veracruz, Mexico, were analyzed for organochlorine pesticides, PCBs, and PBDEs. p,p′-DDE was the only organochlorine found in all eggs at concentrations ranging from 0.13 to 7.85 μg/g wet weight. PCBs ranged from 0.04 to 2.80 μg/g wet weight and PBDEs from 62 to 798 ng/g lipid weight. DDE concentrations in eggs were not significantly different among regions; however, PCBs were significantly greater (P = 0.015) in Tinaja Verde, Chihuahua than in the other three regions. Also, PBDEs were significantly higher (P < 0.0001) in eggs from Veracruz than in those from Chihuahua. DDE concentrations in eggs were much lower than those associated with eggshell thinning. PBDEs and PCBs were lower than those reported in raptors from industrialized countries. Overall, contaminant concentrations observed suggest no likely impact on hatching success. The PBDE concentrations are among the first to be reported in raptor species in Mexico. [Copyright &y& Elsevier]

The present study reports measured levels of organochlorine pesticides (OCPs) in commercial salmon feed ( n = 8) and farmed Atlantic, coho, and chinook salmon ( n = 110), as well as wild coho, chinook, chum, sockeye, and pink salmon ( n = 91). Flesh residue concentrations (ng/g wet weight) of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), chlordanes, chlorobenzenes (CBz) and cyclodiene pesticides (e.g., dieldrin, mirex) were 2 to 11 times higher ( p < 0.05) in farmed salmon compared with wild salmon. Concentrations were positively correlated with flesh lipid levels. Farmed Atlantic salmon (12-15% lipid) typically exhibited the greatest OCP burdens compared with other salmon species. However, when expressed on a lipid weight basis, concentrations of OCPs (ng/g lipid weight) in wild salmon, in many cases, exceeded those levels in farmed salmon. Observed interspecies and site-specific variations of OCP concentrations in farmed and wild salmon may be attributed to divergent life history, prey/feed characteristics and composition, bioenergetics, or ambient environmental concentrations. Calculated biomagnification factors (BMF = CF/ CD, lipid wt) of OCPs in farmed salmon typically ranged between two and five. Biomagnification of chemicals such as DDTs, chlordanes, and mirex was anticipated, because those compounds tend to exhibit high dietary uptake and slow depuration rates in fish because of relatively high octanol-water partition coefficients ( KOWs > 105). Surprisingly, less hydrophobic pesticides such as hexachlorocyclohexanes and endosulfans ( KOWs < 105) consistently exhibited a high degree of biomagnification in farmed salmon species (BMFs > 5). This is contrary to previous laboratory and field observations demonstrating fish BMFs less than 1 for low KOW chemicals, because of efficient respiratory elimination of those compounds via gills. The results suggest that ambient seawater concentrations and bioconcentration-driven accumulation may play a key role in the bioaccumulation of these relatively more water-soluble contaminants in farmed salmon. Finally, OCP exposure through consumption of British Columbian salmon is found to be low relative to United States national average per capita total exposure levels and provisional tolerable daily intakes. Environ. Toxicol. Chem. 2011;30:2456-2464. © 2011 SETAC [ABSTRACT FROM AUTHOR]

Current pesticide risk assessment does not specifically consider amphibians. Amphibians in the aquatic environment (aquatic life stages or postmetamorphic aquatic amphibians) and terrestrial living juvenile or adult amphibians are assumed to be covered by the risk assessment for aquatic invertebrates and fish, or mammals and birds, respectively. This procedure has been evaluated as being sufficiently protective regarding the acute risk posed by a number of pesticides to aquatic amphibian life stages (eggs, larvae). However, it is unknown whether the exposure and sensitivity of terrestrial living amphibians are comparable to mammalian and avian exposure and sensitivity. We reviewed the literature on dermal pesticide absorption and toxicity studies for terrestrial life stages of amphibians, focusing on the dermal exposure pathway, that is, through treated soil or direct overspray. In vitro studies demonstrated that cutaneous absorption of chemicals is significant and that chemical percutaneous passage, P (cm/h), is higher in amphibians than in mammals. In vivo, the rapid and substantial uptake of the herbicide atrazine from treated soil by toads ( Bufo americanus) has been described. Severe toxic effects on various amphibian species have been reported for field-relevant application rates of different pesticides. In general, exposure and toxicity studies for terrestrial amphibian life stages are scarce, and the reported data indicate the need for further research, especially in light of the global amphibian decline. Environ. Toxicol. Chem. 2011;30:2465-2472. © 2011 SETAC [ABSTRACT FROM AUTHOR]

Ireland has a restricted small mammal prey guild but still includes species most likely to consume anticoagulant rodenticide (AR) baits. This may enhance secondary exposure of predators to ARs. We compared liver AR residues in foxes (Vulpes vulpes) in Northern Ireland (NI) with those in foxes from Great Britain which has a more diverse prey guild but similar agricultural use of ARs. Liver ARs were detected in 84% of NI foxes, more than in a comparable sample of foxes from Scotland and similar to that of suspected AR poisoned animals from England and Wales. High exposure in NI foxes is probably due to greater predation of commensal rodents and non-target species most likely to take AR baits, and may also partly reflect greater exposure to highly persistent brodifacoum and flocoumafen. High exposure is likely to enhance risk and Ireland may be a sentinel for potential effects on predator populations. [Copyright &y& Elsevier]

The Sooty Shearwater (Puffinus griseus, commonly known as Mutton bird) is a migratory wild seabird, annually harvested for food by certain native groups in New Zealand and Australia and in many parts of the world. The concentrations of 22 elements and several organochlorine pesticides [2,2-bis(chlorophenyl)-1,1,1-trichloroethane (DDT), its derivatives dichlorodiphenyldichloroethene (DDE) and dichlorodiphenyldichloroethane (DDD), aldrin, chlordane, dicofol, lindane, and methoxychlor] in Mutton bird were determined over two consecutive years to evaluate its safety for human consumption. Twenty bird carcasses were purchased in each of 2007 and 2008 from a local source. No significant year effect (P>0.05) was found in the following nine trace elements: Al, As, Cd, Co, Cr, Cu, Ni, Pb and Se. The concentrations of Hg, Li and Na were higher (P<0.05) in 2008 samples compared to 2007. The toxic trace elements (mg/kg wet weight) in all the samples were below the maximum residual level (MRL). The concentration of Fe, Ca and Se in Mutton bird was higher than that in domestic land animal meats reported in literature. The residual organochlorine concentrations were all below the recommended MRL. Thus Mutton bird meat is high in essential nutrient elements and of low toxicological risk. Due to active use of agrochemical in New Zealand, a monitoring program for contaminants in Mutton birds is recommended. [Copyright &y& Elsevier]

One focus of integrated pest management (IPM) is the use of biological and chemical control in an optimal way. The availability of selective pesticides is important as is information about both lethal and sublethal effects of pesticides on biocontrol agents. Acute and sublethal effects of imidacloprid and fenpyroximate exposure were studied on adult stage of egg parasitoid Trichogramma cacoeciae Marchal and the emergence rate and life table parameters were determined. The adult wasps were exposed to field recommended concentration (FRC) of the pesticides on glass plates. Field rates of imidacloprid and fenpyroximate caused 100 and 32% adult mortality, respectively. Based on concentration-response experiments, the LC values of imidacloprid and fenpyroximate were 6.25 and 1,949 ppm, respectively. The effect of imidacloprid and fenpyroximate on larvae, prepupae and pupae of the parasitoid was tested by exposing parasitized eggs of Sitotroga cerealella Olivier or Cydia pomonella L. to the FRC. Imidacloprid and fenpyroximate reduced adult emergence by 10.7 and 29%, respectively, when S. cerealella eggs were used as the host and 10.9 and 24.9%, respectively, when C. pomonella eggs were used as the host. Population parameters of emerged adults from treated pre-imaginal stages by FRC of the pesticides were also studied. The parameters were longevity and progeny production of emergent adults and also intrinsic rate of increase ( r), generation time ( T) and doubling time ( DT). Longevity and progeny production of the emergent adults was not affected by pesticide exposure in comparison to the control. In addition, none of population parameters such as r, T and DT were affected by pesticide exposure. The intrinsic rate of increase for the control, fenpyroximate and imidacloprid exposed populations were 0.388, 0.374, and 0.372 female offspring per female per day, respectively. Overall, results of this study suggest a relative compatibility between fenpyroximate and T. cacoeciae, but imidacloprid showed deleterious effects on adults of the parasitoid. [ABSTRACT FROM AUTHOR]

Two hundred sediment samples were collected and their toxicity evaluated to aquatic species in a previous study in the agriculturally dominated Central Valley of California, United States. Pyrethroid insecticides were the main contributors to the observed toxicity. However, mortality in approximately one third of the toxic samples could not be explained solely by the presence of pyrethroids in the matrices. Hundreds of pesticides are currently used in the Central Valley of California, but only a few dozen are analyzed in standard environmental monitoring. A significant amount of unexplained sediment toxicity may be due to pesticides that are in widespread use that but have not been routinely monitored in the environment, and even if some of them were, the concentrations harmful to aquatic organisms are unknown. In this study, toxicity thresholds for nine sediment-associated pesticides including abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin were established for two aquatic species, the midge Chironomus dilutus and the amphipod Hyalella azteca. For midges, the median lethal concentration (LC) of the pesticides ranged from 0.18 to 964 μg/g organic carbon (OC), with abamectin being the most toxic and propargite being the least toxic pesticide. A sublethal growth endpoint using average individual ash-free dry mass was also measured for the midges. The no-observable effect concentration values for growth ranged from 0.10 to 633 μg/g OC for the nine pesticides. For the amphipods, fenpropathrin was the most toxic, with an LC of 1-2 μg/g OC. Abamectin, diazinon, and methyl parathion were all moderately toxic (LCs 2.8-26 μg/g OC). Dicofol, indoxacarb, oxyfluorfen, propargite, and pyraclostrobin were all relatively nontoxic, with LCs greater than the highest concentrations tested. The toxicity information collected in the present study will be helpful in decreasing the frequency of unexplained sediment toxicity in agricultural waterways. [ABSTRACT FROM AUTHOR]