Criteria for establishing water quality standards that are protective for 95% of the native speci... more Criteria for establishing water quality standards that are protective for 95% of the native species are generally based upon laboratory toxicity tests. These tests utilize common model organisms that have established test methods. However, for invertebrates these species represent mostly the zooplankton community and are not inclusive of all taxa. In order to examine a potential under-representation in emerging aquatic invertebrates the US Environmental Protection Agency has cultured a parthenogenetic mayfly, Centroptilum triangulifer (Ephemeroptera: Baetidae). This study established a 48h acute and a 14-day short-term chronic testing procedure for C. triangulifer and compared its sensitivity to two model invertebrates, Ceriodaphnia dubia and Daphnia magna. Toxicity tests were conducted to determine mortality and growth effects using standard reference toxicants: NaCl, KCl and CuSO4. In 48-h acute tests, the average LC50 for the mayfly was 659mgL(-1) NaCl, 1957mgL(-1) KCl, and 11μgL(-1) CuSO4. IC25 values, using dry weight as the endpoint, were 228mgL(-1) NaCl, 356mgL(-1) KCl and 5μgL(-1) CuSO4. C. triangulifer was the most sensitive species in NaCl acute and chronic growth tests. At KCl concentrations tested, C. triangulifer was less sensitive for acute tests but was equally or more sensitive than C. dubia and D. magna for growth measurements. This study determined C. triangulifer has great potential and benefits for use in ecotoxicological studies.
Increased inputs of both fine sediments and nutrients to streams are associated with alterations ... more Increased inputs of both fine sediments and nutrients to streams are associated with alterations of catchment land cover. However, the mechanisms by which altered land cover causes increased inputs differs between sediments and nutrients. This results in variation in the relative roles of these stressors in reducing biotic integrity in different stream reaches. Therefore, research that differentiates the relative effects
Weâ€TMre the leading free Book for the world. Platform is a high quality resource for free e-book... more Weâ€TMre the leading free Book for the world. Platform is a high quality resource for free e-books books.Here is the websites where you can download eBooks. Best sites for books in any format enjoy it and don't forget to bookmark and share the love!The Open Library has more than 123,000 free e-books available.If you're looking for a wide variety of books in various categories, check out this site.Look here for bestsellers, favorite classics and more.
Environmental Toxicology and Chemistry, Mar 1, 1996
Abstract The fathead minnow (Pimephales promelas) larval survival and growth test was used to eva... more Abstract The fathead minnow (Pimephales promelas) larval survival and growth test was used to evaluate the relative sensitivity of 1-, 4-, and 7-d-old larvae to five contaminants, KCl, NaCl, 1-octanol, carbaryl, and benzaldehyde. The no observable effect concentration ( ...
Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urg... more Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citrate-coated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO(3) and AgNPs have distinct expression profiles suggesting different modes of toxicity. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO(3) caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed.
Antibiotics play a pivotal role in the management of infectious disease in humans, companion anim... more Antibiotics play a pivotal role in the management of infectious disease in humans, companion animals, livestock, and aquaculture operations at a global scale. Antibiotics are produced, consumed, and released into the environment at an unprecedented scale causing concern that the presence of antibiotic residues may adversely impact aquatic and terrestrial ecosystems. Here we critically review the ecotoxicological assessment of antibiotics as related to environmental risk assessment (ERA). We initially discuss the need for more specific protection goals based on the ecosystem service concept, and suggest that the ERA of antibiotics, through the application of a mode of toxic action approach, should make more use of ecotoxicological endpoints targeting microorganisms (especially bacteria) and microbial communities. Key ecosystem services provided by microorganisms and associated ecosystem service-providing units (e.g. taxa or functional groups) are identified. Approaches currently available for elucidating ecotoxicological effects on microorganisms are reviewed in detail and we conclude that microbial community-based tests should be used to complement single-species tests to offer more targeted protection of key ecosystem services. Specifically, we propose that ecotoxicological tests should not only assess microbial community function, but also microbial diversity (‘species’ richness) and antibiotic susceptibility. Promising areas for future basic and applied research of relevance to ERA are highlighted throughout the text. In this regard, the most fundamental knowledge gaps probably relate to our rudimentary understanding of the ecological roles of antibiotics in nature and possible adverse effects of environmental pollution with subinhibitory levels of antibiotics.
Environmental Toxicology and Chemistry, Nov 1, 2002
During the past 20 years, the role of sediment toxicity tests has expanded from testing of primar... more During the past 20 years, the role of sediment toxicity tests has expanded from testing of primarily dredged material to risk assessment, decontamination technologies, large-scale regional sediment-quality assessments, and toxicity identification evaluations. Sediment toxicity tests are needed that can provide reliable data using less sediment and smaller test chambers, thus utilizing resources more efficiently. We compared survival results from 10-d standard marine amphipod tests at 20 degrees C using 200 ml of sediment to reduced-volume tests containing 20 or 50 ml of sediment and found no significant differences. Similar survival also was observed in tests conducted for 7-d at 23 degrees C versus the standard 10-d exposure at 20 degrees C. However, amphipod sensitivity was significantly less in reduced-volume tests conducted for only 4- or 7-d at 20 degrees C. The 10-d sediment toxicity tests using 50 ml of sediment provided comparable results to the standard protocol, whereas time for sampling, preparing, and sieving sediments for a test was substantially reduced.
Potential exposure to active pharmaceutical ingredients (APIs) in the aquatic environment is a su... more Potential exposure to active pharmaceutical ingredients (APIs) in the aquatic environment is a subject of ongoing concern. We recently published maximum likely exposure rates for several hundred human prescription pharmaceuticals commonly used in the US. These rates were estimated from nationally aggregated marketing data and wastewater production rates. The accuracy of these estimates is unclear, and it is unclear how to use the national-level estimates of exposure to predict local exposure rates. In this study we compare our previous predicted environmental concentrations (PECs), which were based on marketing data, with PECs based on regulatory data. We then use local dispensing rates for 12 APIs along with local wastewater production rates to estimate the distribution of local PECs relative to national averages, in order to identify an 'application factor' suitable for converting national-level PECs into reliable bounds for local concentrations. We compare the national-level PECs and the proposed application factor with measured environmental concentrations (MECs) published in 62 recent peer-reviewed publications. Regulatory data-based national average PECs are uniformly lower than marketing data-based national average PECs, corroborating the intended conservative nature of the marketing data-based PECs. Variability in local API usage and wastewater production rates suggest local PECs may occasionally exceed national averages by about 10-fold. Multiplying national average PECs by an 'application factor' of 10 and comparing the resulting predicted maximum local PECs to published MEC data for 83 APIs corroborates the usefulness of 10-fold adjusted national PECs as a reasonable ceiling for measured environmental concentrations.
Criteria for establishing water quality standards that are protective for 95% of the native speci... more Criteria for establishing water quality standards that are protective for 95% of the native species are generally based upon laboratory toxicity tests. These tests utilize common model organisms that have established test methods. However, for invertebrates these species represent mostly the zooplankton community and are not inclusive of all taxa. In order to examine a potential under-representation in emerging aquatic invertebrates the US Environmental Protection Agency has cultured a parthenogenetic mayfly, Centroptilum triangulifer (Ephemeroptera: Baetidae). This study established a 48h acute and a 14-day short-term chronic testing procedure for C. triangulifer and compared its sensitivity to two model invertebrates, Ceriodaphnia dubia and Daphnia magna. Toxicity tests were conducted to determine mortality and growth effects using standard reference toxicants: NaCl, KCl and CuSO4. In 48-h acute tests, the average LC50 for the mayfly was 659mgL(-1) NaCl, 1957mgL(-1) KCl, and 11μgL(-1) CuSO4. IC25 values, using dry weight as the endpoint, were 228mgL(-1) NaCl, 356mgL(-1) KCl and 5μgL(-1) CuSO4. C. triangulifer was the most sensitive species in NaCl acute and chronic growth tests. At KCl concentrations tested, C. triangulifer was less sensitive for acute tests but was equally or more sensitive than C. dubia and D. magna for growth measurements. This study determined C. triangulifer has great potential and benefits for use in ecotoxicological studies.
Increased inputs of both fine sediments and nutrients to streams are associated with alterations ... more Increased inputs of both fine sediments and nutrients to streams are associated with alterations of catchment land cover. However, the mechanisms by which altered land cover causes increased inputs differs between sediments and nutrients. This results in variation in the relative roles of these stressors in reducing biotic integrity in different stream reaches. Therefore, research that differentiates the relative effects
Weâ€TMre the leading free Book for the world. Platform is a high quality resource for free e-book... more Weâ€TMre the leading free Book for the world. Platform is a high quality resource for free e-books books.Here is the websites where you can download eBooks. Best sites for books in any format enjoy it and don't forget to bookmark and share the love!The Open Library has more than 123,000 free e-books available.If you're looking for a wide variety of books in various categories, check out this site.Look here for bestsellers, favorite classics and more.
Environmental Toxicology and Chemistry, Mar 1, 1996
Abstract The fathead minnow (Pimephales promelas) larval survival and growth test was used to eva... more Abstract The fathead minnow (Pimephales promelas) larval survival and growth test was used to evaluate the relative sensitivity of 1-, 4-, and 7-d-old larvae to five contaminants, KCl, NaCl, 1-octanol, carbaryl, and benzaldehyde. The no observable effect concentration ( ...
Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urg... more Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citrate-coated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO(3) and AgNPs have distinct expression profiles suggesting different modes of toxicity. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO(3) caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed.
Antibiotics play a pivotal role in the management of infectious disease in humans, companion anim... more Antibiotics play a pivotal role in the management of infectious disease in humans, companion animals, livestock, and aquaculture operations at a global scale. Antibiotics are produced, consumed, and released into the environment at an unprecedented scale causing concern that the presence of antibiotic residues may adversely impact aquatic and terrestrial ecosystems. Here we critically review the ecotoxicological assessment of antibiotics as related to environmental risk assessment (ERA). We initially discuss the need for more specific protection goals based on the ecosystem service concept, and suggest that the ERA of antibiotics, through the application of a mode of toxic action approach, should make more use of ecotoxicological endpoints targeting microorganisms (especially bacteria) and microbial communities. Key ecosystem services provided by microorganisms and associated ecosystem service-providing units (e.g. taxa or functional groups) are identified. Approaches currently available for elucidating ecotoxicological effects on microorganisms are reviewed in detail and we conclude that microbial community-based tests should be used to complement single-species tests to offer more targeted protection of key ecosystem services. Specifically, we propose that ecotoxicological tests should not only assess microbial community function, but also microbial diversity (‘species’ richness) and antibiotic susceptibility. Promising areas for future basic and applied research of relevance to ERA are highlighted throughout the text. In this regard, the most fundamental knowledge gaps probably relate to our rudimentary understanding of the ecological roles of antibiotics in nature and possible adverse effects of environmental pollution with subinhibitory levels of antibiotics.
Environmental Toxicology and Chemistry, Nov 1, 2002
During the past 20 years, the role of sediment toxicity tests has expanded from testing of primar... more During the past 20 years, the role of sediment toxicity tests has expanded from testing of primarily dredged material to risk assessment, decontamination technologies, large-scale regional sediment-quality assessments, and toxicity identification evaluations. Sediment toxicity tests are needed that can provide reliable data using less sediment and smaller test chambers, thus utilizing resources more efficiently. We compared survival results from 10-d standard marine amphipod tests at 20 degrees C using 200 ml of sediment to reduced-volume tests containing 20 or 50 ml of sediment and found no significant differences. Similar survival also was observed in tests conducted for 7-d at 23 degrees C versus the standard 10-d exposure at 20 degrees C. However, amphipod sensitivity was significantly less in reduced-volume tests conducted for only 4- or 7-d at 20 degrees C. The 10-d sediment toxicity tests using 50 ml of sediment provided comparable results to the standard protocol, whereas time for sampling, preparing, and sieving sediments for a test was substantially reduced.
Potential exposure to active pharmaceutical ingredients (APIs) in the aquatic environment is a su... more Potential exposure to active pharmaceutical ingredients (APIs) in the aquatic environment is a subject of ongoing concern. We recently published maximum likely exposure rates for several hundred human prescription pharmaceuticals commonly used in the US. These rates were estimated from nationally aggregated marketing data and wastewater production rates. The accuracy of these estimates is unclear, and it is unclear how to use the national-level estimates of exposure to predict local exposure rates. In this study we compare our previous predicted environmental concentrations (PECs), which were based on marketing data, with PECs based on regulatory data. We then use local dispensing rates for 12 APIs along with local wastewater production rates to estimate the distribution of local PECs relative to national averages, in order to identify an 'application factor' suitable for converting national-level PECs into reliable bounds for local concentrations. We compare the national-level PECs and the proposed application factor with measured environmental concentrations (MECs) published in 62 recent peer-reviewed publications. Regulatory data-based national average PECs are uniformly lower than marketing data-based national average PECs, corroborating the intended conservative nature of the marketing data-based PECs. Variability in local API usage and wastewater production rates suggest local PECs may occasionally exceed national averages by about 10-fold. Multiplying national average PECs by an 'application factor' of 10 and comparing the resulting predicted maximum local PECs to published MEC data for 83 APIs corroborates the usefulness of 10-fold adjusted national PECs as a reasonable ceiling for measured environmental concentrations.
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