Estado da arte e perspectivas da avaliação ecotoxicológica de áreas contaminadas

Over the past two decades, soil ecotoxicologists have made strides in utilizing the basic concepts and advancements in soil zoology and ecology. They have applied the existing tools, and developed new ones to investigate how chemical contamination can affect soil ecosystems, including the degradation or destruction of soil quality and habitats or the diminishment of belowground biodiversity. Soil ecotoxicologists are applying a suite of standard protocols, originally developed as laboratory tests with single chemicals (e.g., pesticides), and further enhancing both the approaches and protocols for the assessment of contaminated lands. However, ecological relevance of some approaches remains unresolved. The authors discuss the main challenges for a coherent ecotoxicological assessment of soil ecosystems amid contaminated lands, and provide recommendations on how to integrate the effects of physical and chemical soil properties, the variations in the diversity of soil invertebrates, and the interactions among organisms of various trophic levels. The review examines new international approaches and test methods using examples from three continents (in particular research conducted in Brazil), and provides recommendations for improving ecological relevance of ecotoxicological investigations of contaminated lands.Durante as últimas duas décadas, ecotoxicologistas de solo têm feito progressos ao utilizar conceitos básicos e avanços da zoologia e ecologia do solo. Os métodos existentes têm sido aplicados, e têm-se desenvolvido novas ferramentas para avaliar de que modo a contaminação química pode afetar o ecossistema terrestre, inclusive pela degradação ou destruição da qualidade do solo e dos habitats ou pela redução da biodiversidade edáfica. Os ecotoxicologistas de solo utilizam um conjunto de protocolos padronizados, originalmente desenvolvidos como testes de laboratório com compostos químicos simples como os pesticidas e, posteriormente, adaptados em termos de abordagens e métodos, para a avaliação de áreas contaminadas. No entanto, a relevância ecológica de algumas abordagens permanece questionável. Neste artigo, os autores discutem os recentes desafios para uma avaliação ecotoxicológica coerente do ecossistema solo em áreas contaminadas e apresentam recomendações de como integrar os efeitos das propriedades físicoquímicas do solo, as variações na diversidade de invertebrados do solo e, as interações entre organismos dos vários níveis tróficos. São analisadas novas abordagens e métodos de avaliação, usando-se exemplos de três continentes (particularmente o trabalho desenvolvido no Brasil), e são dadas recomendações de como aumentar a relevância ecológica na avaliação ecotoxicológica de áreas contaminadas

Reproduction and survival of Eisenia fetida in a sandy loam soil amended with the nitro-heterocyclic explosives RDX and HMX

Munitions manufacturing, disposal, testing, training and other operations at military sites have produced elevated levels of explosives and related materials in soil. Insufficient data were available on the toxicity of the explosives, RDX and HMX to soil invertebrates, necessitating toxicity testing. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a sandy loam soil that supports relatively high bioavailability of test compounds. Earthworm (Eisenia fetida) toxicity was assessed using a standardized earthworm reproduction test in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival. Cocoon production EC20 values for RDX were 1.2 and 19 mg kg-1 in freshly amended and weathered/aged soils, respectively. Juvenile production EC20 values were 1.6 and 4.8 mg kg-1 in freshly amended and weathered/aged soils, respectively. Cocoon production and juvenile production EC20 values for HMX were 2.7 and 0.4 mg kg-1 in freshly amended soil. Both cocoon production and juvenile production in weathered/aged HMX treated soils were not significantly different (p > 0.05) from control soils. Results of these toxicity studies will be submitted to the Eco-SSL Task Group and will be included in the Eco-SSL database for Eco-SSL derivation.Munitions manufacturing, disposal, testing, training and other operations at military sites have produced elevated levels of explosives and related materials in soil. Insufficient data were available on the toxicity of the explosives, RDX and HMX to soil invertebrates, necessitating toxicity testing. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a sandy loam soil that supports relatively high bioavailability of test compounds. Earthworm (Eisenia fetida) toxicity was assessed using a standardized earthworm reproduction test in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival. Cocoon production EC20 values for RDX were 1.2 and 19 mg kg-1 in freshly amended and weathered/aged soils, respectively. Juvenile production EC20 values were 1.6 and 4.8 mg kg-1 in freshly amended and weathered/aged soils, respectively. Cocoon production and juvenile production EC20 values for HMX were 2.7 and 0.4 mg kg-1 in freshly amended soil. Both cocoon production and juvenile production in weathered/aged HMX treated soils were not significantly different (p > 0.05) from control soils. Results of these toxicity studies will be submitted to the Eco-SSL Task Group and will be included in the Eco-SSL database for Eco-SSL derivation.NRC publication: Ye

Survival and reproduction of Enchytraeus crypticus (Oligochaeta, Enchytraeidae) in a natural sandy loam soil amended with the nitro-heterocyclic explosives RDX and HMX

Munition manufacturing, disposal, testing, training and other operations at military sites produced elevated levels of explosives and related materials in soil. The effects of these persistent and highly mobile in the environment energetic materials on soil biota have not been sufficiently investigated. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a Baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Insufficient data were available on the toxicity of energetic compounds, RDX and HMX, to soil invertebrates, necessitating toxicity testing. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a Sassafras sandy loam soil that supports relatively high bioavailability of test compounds. Toxicity testing was performed using enchytraeid reproduction test (ISO/16387 2001) measuring adult survival and juvenile production by the potworm Enchytraeus crypticus in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival in the definitive tests in all treatment concentrations. Juvenile production EC20 values were 3,715 and 8,797 mg kg-1 RDX in freshly amended and weathered/aged amended soils, respectively. Juvenile E. crypticus production was not adversely affected by exposure to HMX in freshly amended and weathered/aged amended soils. Juvenile production was stimulated in freshly amended soil up to 21,750 mg kg-1 HMX. Results of these toxicity studies will be submitted to the Eco-SSL Task Group for quality control review, and pending approval will be included in the Eco-SSL database for Eco-SSL derivation.NRC publication: Ye

Toxicity of 2,4-dinitrotoluene to terrestrial plants in natural soils

The presence of energetic materials (used as explosives and propellants) at contaminated sites is a growing international issue, particularly with respect to military base closures and demilitarization policies. Improved understanding of the ecotoxicological effects of these materials is needed in order to accurately assess the potential exposure risks and impacts on the environment and its ecosystems. We studied the toxicity of the nitroaromatic energetic material 2,4-dinitrotoluene (2,4-DNT) on alfalfa (Medicago sativa L.), barnyard grass (Echinochloa crusgalli L. Beauv.), and perennial ryegrass (Lolium perenne L.) using four natural soils varying in properties (organic matter, clay content, and pH) that were hypothesized to affect chemical bioavailability and toxicity. Amended soils were subjected to natural light conditions, and wetting and drying cycles in a greenhouse for 13 weeks prior to toxicity testing to approximate field exposure conditions in terms of bioavailability, transformation, and degradation of 2,4-DNT. Definitive toxicity tests were performed according to standard protocols. The median effective concentration (EC50) values for shoot dry mass ranged from 8 to 229 mg kg- 1, depending on the plant species and soil type. Data indicated that 2,4-DNT was most toxic in the Sassafras (SSL) and Teller (TSL) sandy loam soils, with EC50 values for shoot dry mass ranging between 8 to 44 mg kg- 1, and least toxic in the Webster clay loam soil, with EC50 values for shoot dry mass ranging between 40 to 229 mg kg- 1. The toxicity of 2,4-DNT for each of the plant species was significantly (p ? 0.05) and inversely correlated with the soil organic matter content. Toxicity benchmark values determined in the present studies for 2,4-DNT weathered-and-aged in SSL or TSL soils will contribute to development of an Ecological Soil Screening Level for terrestrial plants that can be used for ecological risk assessment at contaminated sites. Crown Copyright \ua9 2010.Peer reviewed: YesNRC publication: Ye

Estado da arte e perspectivas da avaliação ecotoxicológica de áreas contaminadas

Over the past two decades, soil ecotoxicologists have made strides in utilizing the basic concepts and advancements in soil zoology and ecology. They have applied the existing tools, and developed new ones to investigate how chemical contamination can affect soil ecosystems, including the degradation or destruction of soil quality and habitats or the diminishment of belowground biodiversity. Soil ecotoxicologists are applying a suite of standard protocols, originally developed as laboratory tests with single chemicals (e.g., pesticides), and further enhancing both the approaches and protocols for the assessment of contaminated lands. However, ecological relevance of some approaches remains unresolved. The authors discuss the main challenges for a coherent ecotoxicological assessment of soil ecosystems amid contaminated lands, and provide recommendations on how to integrate the effects of physical and chemical soil properties, the variations in the diversity of soil invertebrates, and the interactions among organisms of various trophic levels. The review examines new international approaches and test methods using examples from three continents (in particular research conducted in Brazil), and provides recommendations for improving ecological relevance of ecotoxicological investigations of contaminated lands.Durante as últimas duas décadas, ecotoxicologistas de solo têm feito progressos ao utilizar conceitos básicos e avanços da zoologia e ecologia do solo. Os métodos existentes têm sido aplicados, e têm-se desenvolvido novas ferramentas para avaliar de que modo a contaminação química pode afetar o ecossistema terrestre, inclusive pela degradação ou destruição da qualidade do solo e dos habitats ou pela redução da biodiversidade edáfica. Os ecotoxicologistas de solo utilizam um conjunto de protocolos padronizados, originalmente desenvolvidos como testes de laboratório com compostos químicos simples como os pesticidas e, posteriormente, adaptados em termos de abordagens e métodos, para a avaliação de áreas contaminadas. No entanto, a relevância ecológica de algumas abordagens permanece questionável. Neste artigo, os autores discutem os recentes desafios para uma avaliação ecotoxicológica coerente do ecossistema solo em áreas contaminadas e apresentam recomendações de como integrar os efeitos das propriedades físicoquímicas do solo, as variações na diversidade de invertebrados do solo e, as interações entre organismos dos vários níveis tróficos. São analisadas novas abordagens e métodos de avaliação, usando-se exemplos de três continentes (particularmente o trabalho desenvolvido no Brasil), e são dadas recomendações de como aumentar a relevância ecológica na avaliação ecotoxicológica de áreas contaminadas

Phytotoxicity and uptake of nitroglycerin in a natural sandy loam soil

Nitroglycerin (NG) is widely used for the production of explosives and solid propellants, and is a soil contaminant of concern at some military training ranges. NG phytotoxicity data reported in the literature cannot be applied directly to development of ecotoxicological benchmarks for plant exposures in soil because they were determined in studies using hydroponic media, cell cultures, and transgenic plants. Toxicities of NG in the present studies were evaluated for alfalfa (Medicago sativa), barnyard grass (Echinochloa crusgalli), and ryegrass (Lolium perenne) exposed to NG in Sassafras sandy loam soil. Uptake and degradation of NG were also evaluated in ryegrass. The median effective concentration values for shoot growth ranged from 40 to 231 mg kg- 1 in studies with NG freshly amended in soil, and from 23 to 185 mg kg- 1 in studies with NG weathered-and-aged in soil. Weathering-and-aging NG in soil did not significantly affect the toxicity based on 95 percent confidence intervals for either seedling emergence or plant growth endpoints. Uptake studies revealed that NG was not accumulated in ryegrass but was transformed into dinitroglycerin in the soil and roots, and was subsequently translocated into the ryegrass shoots. The highest bioconcentration factors for dinitroglycerin of 685 and 40 were determined for roots and shoots, respectively. Results of these studies will improve our understanding of toxicity and bioconcentration of NG in terrestrial plants and will contribute to ecological risk assessment of NG-contaminated sites.Peer reviewed: YesNRC publication: Ye