Wca environment

Faringdon, United Kingdom

Wca environment

Faringdon, United Kingdom

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PubMed | BASF, Dow AgroSciences, WCA Environment, AG HERA and Hill International
Type: | Journal: Regulatory toxicology and pharmacology : RTP | Year: 2016

Amphibians are currently the most threatened and rapidly declining group of vertebrates and this has raised concerns about their potential sensitivity and exposure to plant protection products and other chemicals. Current environmental risk assessment procedures rely on surrogate species (e.g. fish and birds) to cover the risk to aquatic and terrestrial life stages of amphibians, respectively. Whilst a recent meta-analysis has shown that in most cases amphibian aquatic life stages are less sensitive to chemicals than fish, little research has been conducted on the comparative sensitivity of terrestrial amphibian life stages. Therefore, in this paper we address the questions What is the relative sensitivity of terrestrial amphibian life stages to acute chemical oral exposure when compared with mammals and birds? and Are there correlations between oral toxicity data for amphibians and data for mammals or birds? Identifying a relationship between these data may help to avoid additional vertebrate testing. Acute oral amphibian toxicity data collected from the scientific literature and ecotoxicological databases were compared with toxicity data for mammals and birds. Toxicity data for terrestrial amphibian life stages are generally sparse, as noted in previous reviews. Single-dose oral toxicity data for terrestrial amphibian life stages were available for 26 chemicals and these were positively correlated with LD50 values for mammals, while no correlation was found for birds. Further, the data suggest that oral toxicity to terrestrial amphibian life stages is similar to or lower than that for mammals and birds, with a few exceptions. Thus, mammals or birds are considered adequate toxicity surrogates for use in the assessment of the oral exposure route in amphibians. However, there is a need for further data on a wider range of chemicals to explore the wider applicability of the current analyses and recommendations.


Peters A.,Wca environment | Lofts S.,UK Center for Ecology and Hydrology | Merrington G.,Wca environment | Brown B.,Wca environment | And 3 more authors.
Environmental Toxicology and Chemistry | Year: 2011

Ecotoxicity tests were performed with fish, invertebrates, and algae to investigate the effect of water quality parameters on Mn toxicity. Models were developed to describe the effects of Mn as a function of water quality. Calcium (Ca) has a protective effect on Mn toxicity for both fish and invertebrates, and magnesium (Mg) also provides a protective effect for invertebrates. Protons have a protective effect on Mn toxicity to algae. The models derived are consistent with models of the toxicity of other metals to aquatic organisms in that divalent cations can act as competitors to Mn toxicity in fish and invertebrates, and protons act as competitors to Mn toxicity in algae. The selected models are able to predict Mn toxicity to the test organisms to within a factor of 2 in most cases. Under low-pH conditions invertebrates are the most sensitive taxa, and under high-pH conditions algae are most sensitive. The point at which algae become more sensitive than invertebrates depends on the Ca concentration and occurs at higher pH when Ca concentrations are low, because of the sensitivity of invertebrates under these conditions. Dissolved organic carbon concentrations have very little effect on the toxicity of Mn to aquatic organisms. © 2011 SETAC.


Crane M.,Wca environment | Gross M.,Wca environment | Maycock D.S.,Wca environment | Grant A.,VetAqua Scotland | Fossum B.H.,PHARMAQ AS
Aquaculture Research | Year: 2011

This paper describes the use of time to event and Species Sensitivity Distribution (SSD) analyses to derive environmental quality standards (EQS) for the synthetic pyrethroid deltamethrin when used to treat lice in marine finfish aquaculture. Long-term EQS are of limited applicability for parasiticides used in coastal aquaculture because initially high concentrations are rapidly dissipated and diluted. Short-term EQS related to likely exposure duration are a more useful management tool. Accelerated Life Testing was used to analyse high-quality, time-specific survival data (LC10 values) for saltwater fish and crustacean species for which observations on survival over several time periods were available. These data were then plotted as SSDs, allowing the estimation of time-specific median HC5 values, protective of 95% of organisms in saltwater assemblages if the test data are representative of species in the field. These analyses show that after 3h, the HC5 of LC10 values for deltamethrin in saltwater is 9.3ngL -1, declining to 1.4ngL -1 after 48h of continuous exposure. Such values are consistent with data on effect concentrations from other lines of evidence, including mesocosm and field studies, and can be used as time-specific EQS when monitoring discharges from aquaculture facilities immediately after the treatment of fish with deltamethrin. © 2010 The Authors. Journal Compilation © 2010 Blackwell Publishing Ltd.


Peters A.,wca environment | Schlekat C.E.,NiPERA | Merrington G.,wca environment
Environmental Toxicology and Chemistry | Year: 2016

A bioavailability-based environmental quality standard (EQS) was established for nickel in freshwaters under the European Union's Water Framework Directive. Bioavailability correction based on pH, water hardness, and dissolved organic carbon is a demonstrable improvement on existing hardness-based quality standards, which may be underprotective in high-hardness waters. The present study compares several simplified bioavailability tools developed to implement the Ni EQS (biomet, M-BAT, and PNECPro) against the full bioavailability normalization procedure on which the EQS was based. Generally, all tools correctly distinguished sensitive waters from insensitive waters, although with varying degrees of accuracy compared with full normalization. Biomet and M-BAT predictions were consistent with, but less accurate than, full bioavailability normalization results, whereas PNECpro results were generally more conservative. The comparisons revealed important differences in tools in development, which results in differences in the predictions. Importantly, the models used for the development of PNECpro use a different ecotoxicity dataset, and a different bioavailability normalization approach using fewer biotic ligand models (BLMs) than that used for the derivation of the Ni EQS. The failure to include all of the available toxicity data, and all of the appropriate NiBLMs, has led to some significant differences between the predictions provided by PNECpro and those calculated using the process agreed to in Europe under the Water Framework Directive and other chemicals management programs (such as REACH). These considerable differences mean that PNECpro does not reflect the behavior, fate, and ecotoxicity of nickel, and raises concerns about its applicability for checking compliance against the Ni EQS. Environ Toxicol Chem 2016;35:2397–2404. © 2016 SETAC. © 2016 SETAC


A bioavailability-based environmental quality standard (EQS) was established for nickel in freshwaters under the European Unions Water Framework Directive. Bioavailability correction based on pH, water hardness, and dissolved organic carbon is a demonstrable improvement on existing hardness-based quality standards, which may be underprotective in high-hardness waters. The present study compares several simplified bioavailability tools developed to implement the Ni EQS (biomet, M-BAT, and PNECPro) against the full bioavailability normalization procedure on which the EQS was based. Generally, all tools correctly distinguished sensitive waters from insensitive waters, although with varying degrees of accuracy compared with full normalization. Biomet and M-BAT predictions were consistent with, but less accurate than, full bioavailability normalization results, whereas PNECpro results were generally more conservative. The comparisons revealed important differences in tools in development, which results in differences in the predictions. Importantly, the models used for the development of PNECpro use a different ecotoxicity dataset, and a different bioavailability normalization approach using fewer biotic ligand models (BLMs) than that used for the derivation of the Ni EQS. The failure to include all of the available toxicity data, and all of the appropriate NiBLMs, has led to some significant differences between the predictions provided by PNECpro and those calculated using the process agreed to in Europe under the Water Framework Directive and other chemicals management programs (such as REACH). These considerable differences mean that PNECpro does not reflect the behavior, fate, and ecotoxicity of nickel, and raises concerns about its applicability for checking compliance against the Ni EQS. Environ Toxicol Chem 2016;35:2397-2404. 2016 SETAC.


Merrington G.,WCA Environment | Van Sprang P.,ARCHE Assessing Risks of CHEmicals
Environmental Science and Pollution Research | Year: 2014

Recent technical guidance has been published by the European Commission that outlines methodologies for the derivation of Environmental Quality Standards (EQS) in European surface waters under the Water Framework Directive (WFD). The guidance allows the derivation of a long-term EQS from a small dataset. Specifically an EQS can be derived from just three acute data points, although the safety factors built into such an EQS are large (e.g. up to a factor of 1,000). Large safety factors make such EQS uncertain, and often difficult to achieve in practice. We examine dataset requirements for the derivation of EQS and specifically the minimum number of tests needed for setting EQS for long-term chemical exposures that result in reduced relative uncertainty, as assessed simply through the reduction in standard deviation of the means of the values derived. Using ecotoxicity datasets for four example chemicals, for which EQS have been derived in many jurisdictions, we show that variation in the EQS is greatest when using the minimum dataset allowable under the WFD guidance, but decreases rapidly when seven or more datapoints are available. Increasing the minimum number of ecotoxicity data in deriving an EQS results in a greater understanding of ecotoxicological effects. With this knowledge, the mitigating effects of water chemistry can be accounted for in deriving an EQS, even with relatively limited datasets. The new guidance suggests "simplistic" approaches to account for chemical availability, but does not detail how this might be undertaken. We provide examples of ways by which water chemistry effects can be included in deriving implementable EQS for metals with relatively few reliable and relevant data. © 2013 Springer-Verlag Berlin Heidelberg.


Taylor D.,wca environment | Taylor D.,Sanofi S.A. | Senac T.,wca environment | Senac T.,Sanofi S.A.
Chemosphere | Year: 2014

Concerns about the potential for significant environmental impact from residues of human pharmaceuticals emerged at the beginning of the 21st century. Since then there has been an exponential rise in the number of publications and conferences on this "problem". However, this intense focus on human pharmaceuticals is misplaced. Pharmaceuticals do not consist of a coherent group of substances with similar chemical, structural, biological or toxicological properties. Pharmaceuticals are only identifiable from their use: in other words substances can be divided into two classes, those that are used as pharmaceuticals and those for which a possible pharmaceutical use has not yet been discovered. For example, nitro-glycerine, Warfarin and dimethyl fumarate, initially sold respectively as an explosive, a rodenticide and a mould inhibitor have subsequently all been used as pharmaceuticals. As analytical science advances, an increasing range of environmental contaminants, including pharmaceuticals, is being identified at sub μgL-1 concentrations. Although, human and environmental exposure to these contaminants will be low, all of them need to be subjected to risk assessment on a case by case basis. Many of these substances, including human pharmaceuticals, may have little, if any, impact on human health or the environment, however for some substances there may be a significant risk and in these cases appropriate action should be taken. However considering all human pharmaceuticals as a special case, isolated from the wider range of emerging contaminants, is scientifically unjustifiable and diverts resources away from the consideration of other substances that may be of considerably more significance. © 2014 Elsevier Ltd.


Langdon K.A.,CSIRO | Mclaughlin M.J.,CSIRO | Kirby J.K.,CSIRO | Merrington G.,WCA Environment
Environmental Toxicology and Chemistry | Year: 2014

Silver (Ag) is being increasingly used in a range of consumer products, predominantly as an antimicrobial agent, leading to a higher likelihood of its release into the environment. The present study investigated the toxicity of Ag to the nitrification process in European and Australian soils in both leached and unleached conditions. Overall, leaching of soils was found to have a minimal effect on the final toxicity data, with an average leaching factor of approximately 1. Across the soils, the toxicity was found to vary by several orders of magnitude, with concentrations of Ag causing a 50% reduction in nitrification relative to the controls (EC50) ranging from 0.43mg Ag/kg to >640mg Ag/kg. Interestingly, the dose-response relationships in most of the soils showed significant stimulation in nitrification at low Ag concentrations (i.e., hormesis), which in some cases produced responses up to double that observed in the controls. Soil pH and organic carbon were the properties found to have the greatest influence on the variations in toxicity thresholds across the soils, and significant relationships were developed that accounted for approximately 90% of the variability in the data. The toxicity relationships developed from the present study will assist in future assessment of potential Ag risks and enable the site-specific prediction of Ag toxicity. © 2014 SETAC.


Langdon K.A.,CSIRO | Mclaughlin M.J.,CSIRO | Kirby J.K.,CSIRO | Merrington G.,WCA Environment
Environmental Toxicology and Chemistry | Year: 2015

Silver (Ag) has been shown to exhibit antimicrobial properties; as a result, it is being used increasingly in a wide range of consumer products. With these uses, the likelihood that Ag may enter the environment has increased, predominately via land application of biosolids or irrigation with treated wastewater effluent. The aim of the present study was to investigate the toxicity of Ag to 2 plant species: barley (Hordeum vulgare L. CV Triumph) and tomato (Lycopersicum esculentum) in a range of soils under both leached and unleached conditions. The concentrations that resulted in a 50% reduction of plant growth (EC50) were found to vary up to 20-fold across the soils, indicating a large influence of soil type on Ag toxicity. Overall, barley root elongation was found to be the least sensitive to added Ag, with EC50 values ranging from 51mg/kg to 1030mg/kg, whereas the tomato plant height showed higher sensitivity with EC50 values ranging from 46mg/kg to 486mg/kg. The effect of leaching was more evident in the barley toxicity results, where higher concentrations of Ag were required to induce toxicity. Variations in soil organic carbon and pH were found to be primarily responsible for mitigating Ag toxicity; therefore, these properties may be used in future risk assessments for Ag to predict toxicity in a wide range of soil types. © 2015 SETAC.


PubMed | WCA Environment and International Manganese Institute
Type: | Journal: Neurotoxicology | Year: 2016

An environmental risk assessment (ERA) has been conducted for sites producing and processing manganese and its inorganic compounds, focussing on potential risks to freshwater. A site specific questionnaire was used to collect information. Sites fall into three broad categories: mining sites, refining sites, and sites producing chemicals and pigments. Waste disposal is principally carried out by the treatment of liquid wastes to separate solids for disposal off-site with a consented wastewater discharge, or disposal on-site using evaporation or settlement ponds in order to maintain the waste materials in a suitable manner following site closure. The main source of emissions from refining and alloying sites is from the treatment of emissions to air using wet scrubber air filters. There is also the potential for fugitive environmental emissions of manganese from stockpiles of raw material held on-site. Data provided from the questionnaires were both site-specific and also commercially sensitive. Therefore, this paper has undertaken the manganese exposure assessment, using a probabilistic approach to reflect the distribution of emissions of manganese and also to maintain the confidentiality of site specific data. An inverse correlation was observed between the total annual tonnage of manganese processed at the site and the emission factor, such that sites processing larger quantities resulted in lower emissions of manganese per tonne processed. The hazard assessment determined a Predicted No Effect Concentration (PNEC) for freshwater using a species sensitivity distribution approach, resulting in a freshwater PNEC of 0.075mgL

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