Ecological Risk Assessment Approach Research Articles

Application of species sensitivity distribution in aquatic probabilistic ecological risk assessment of cypermethrin: a case study in an urban stream in South China.

A tiered ecological risk assessment was applied to quantitatively refine the overall probabilistic risk of cypermethrin, a pyrethroid insecticide, to aquatic organisms. These results were then validated through the bioassays using field water from an urban stream, Chebei Creek in Guangzhou, South China. Seventeen water samples were collected along Chebei Creek for evaluation. In total, 71% of the field waters were acutely toxic to Hyallela azteca and 24% of the waters caused 100% mortality. Toxic unit evaluation suggested that cypermethrin was one of the main contributors to toxicity. The tiered ecological risk assessment approach (deterministic quotient method and probabilistic methods, including joint probability curve and Monte Carlo Simulation) suggested that cypermethrin posed significant threats to aquatic ecology in this stream. The overall probabilistic risk of cypermethrin to aquatic species in Chebei Creek reached 66% when acute-to-chronic ratios were set at 125. An exceedance probability of cypermethrin in Chebei Creek that affected H. azteca as modeled using the joint probability curve method was 88%, suggesting that most sites were at risk due to cypermethrin exposure. This value was similar to the results obtained from acute toxicity tests (71% of field water samples were acutely toxic to H. azteca), indicating the effectiveness of the tiered approach to assess risk of cypermethrin in urban waterways. To the authors' knowledge, the present study is the first to provide a focused probabilistic evaluation of ecological risk for cypermethrin in a complex urban waterway environment. Despite uncertainties existing in the ecological risk assessment procedure, this approach provides a comprehensive assessment of ecological risk of cypermethrin, and subsequently, a foundation for further risk diagnosis and management in urban waterways.

Probabilistic ecological risk assessment of cadmium in the Bohai Sea using native saltwater species

Predicted no-effect concentration (PNEC) is often used in ecological risk assessment to determine low-risk concentrations for chemicals. In the present study, the chronic data from native saltwater species were used to calculated PNEC values using four methods: log-normal distribution (ETX 2.0), log-triangle distribution (US EPA’s water quality criteria procedure), burr III distribution (BurrliOZ) and traditional assessment factor (AF). The PNECs that were calculated using four methods ranged from 0.08 μg/L to 1.8 μg/L. Three of the SSD-derived PNECs range from 0.94 to 1.8 μg/L, about a factor of two apart. To demonstrate the use of SSD-based PNEC values and comprehensively estimate the regional ecological risk for cadmium in surface water of the Bohai Sea, in the Liaodong Bay, Bohai Bay, and Laizhou Bay, China, the dissolved cadmium concentrations were measured and obtained 753 valid data covering 190 stations from July 2006 to November 2007. Based on three ecological risk assessment approaches, namely hazard quotient (HQ), probabilistic risk quotient and joint probability curve (JPC), the potential ecological risk of cadmium in surface water of the Liaodong Bay, Bohai Bay, and Laizahou Bay were estimated. Overall, the ecological risk of cadmium to aquatic ecosystem in the whole Bohai Sea was at acceptable ecological risk level, the order of ecological risk was Liaodong Bay>Bohai Bay>Laizhou Bay. However, more concerns should be paid to aquatic ecological risk in the Liaodong Bay which is the home of many steel, metallurgy and petrochemical industrial in China.

Ecological Risk Assessment of Pesticide Residues in Water from Desert Locust Area in Burkina Faso

Locust control requires sometimes an important use of pesticides in infested area with concomitant environment contaminations. Using the Gas Chromatography (GC) technical, pesticide residues were determined in water samples collected from locust outbreak areas of Burkina Faso, West Africa. The risk quotient method coupled with probabilistic risk assessment model was used for ecological risk assessment of pesticide detected in water. For ten pesticides belonging to Organophosphates, Pyrethroid and Phenylpyrazole chemical class, only diazinon was detected in water samples from all sites with content ranging from 2.02 to 2.21 µg/L. The presence of pesticide residues seem to be linked to specific agropedoclimatic conditions of study area. Results of risk assessment show that diazinon level in water generates a risk for considered groups of aquatic organisms following this decreasing order: Aquatic invertebrates ˃Crustacean˃Fish˃Algae. This risk is particularly important if only most sensible group of organisms is taken account or if probabilistic risk assessment is applied. The findings suggest that pesticides in locust control generate a potential hazard for aquatic organisms. Cautious or restrictive use of these agrochemicals in the Sahelian context is recommended. Moreover, Ecological risk assessment approach that we applied can provide more information for risk managers and decision makers.

Evaluation of New Zealand's high-seas bottom trawl closures using predictive habitat models and quantitative risk assessment.

United Nations General Assembly Resolution 61/105 on sustainable fisheries (UNGA 2007) establishes three difficult questions for participants in high-seas bottom fisheries to answer: 1) Where are vulnerable marine systems (VMEs) likely to occur?; 2) What is the likelihood of fisheries interaction with these VMEs?; and 3) What might qualify as adequate conservation and management measures to prevent significant adverse impacts? This paper develops an approach to answering these questions for bottom trawling activities in the Convention Area of the South Pacific Regional Fisheries Management Organisation (SPRFMO) within a quantitative risk assessment and cost : benefit analysis framework. The predicted distribution of deep-sea corals from habitat suitability models is used to answer the first question. Distribution of historical bottom trawl effort is used to answer the second, with estimates of seabed areas swept by bottom trawlers being used to develop discounting factors for reduced biodiversity in previously fished areas. These are used in a quantitative ecological risk assessment approach to guide spatial protection planning to address the third question. The coral VME likelihood (average, discounted, predicted coral habitat suitability) of existing spatial closures implemented by New Zealand within the SPRFMO area is evaluated. Historical catch is used as a measure of cost to industry in a cost : benefit analysis of alternative spatial closure scenarios. Results indicate that current closures within the New Zealand SPRFMO area bottom trawl footprint are suboptimal for protection of VMEs. Examples of alternative trawl closure scenarios are provided to illustrate how the approach could be used to optimise protection of VMEs under chosen management objectives, balancing protection of VMEs against economic loss to commercial fishers from closure of historically fished areas.

Ecological Risk Assessment of Chemicals Migrated from a Recycled Plastic Product

ObjectivesPotential environmental risks caused by chemicals that could be released from a recycled plastic product were assessed using a screening risk assessment procedure for chemicals in recycled products.MethodsPlastic slope protection blocks manufactured from recycled plastics were chosen as model recycled products. Ecological risks caused by four model chemicals -di-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), cadmium (Cd), and lead (Pb)- were assessed. Two exposure models were built for soil below the block and a hypothetic stream receiving runoff water. Based on the predicted no-effect concentrations for the selected chemicals and exposure scenarios, the allowable leaching rates from and the allowable contents in the recycled plastic blocks were also derived.ResultsEnvironmental risks posed by slope protection blocks were much higher in the soil compartment than in the hypothetic stream. The allowable concentrations in leachate were 1.0×10-4, 1.2×10-5, 9.5×10-3, and 5.3×10-3 mg/L for DEHP, DINP, Cd, and Pb, respectively. The allowable contents in the recycled products were 5.2×10-3, 6.0×10-4, 5.0×10-1, and 2.7×10-1 mg/kg for DEHP, DINP, Cd, and Pb, respectively.ConclusionsA systematic ecological risk assessment approach for slope protection blocks would be useful for regulatory decisions for setting the allowable emission rates of chemical contaminants, although the method needs refinement.

A sediment ecotoxicity assessment platform for in situ measures of chemistry, bioaccumulation and toxicity. Part 2: Integrated application to a shallow estuary

A comprehensive, weight-of-evidence based ecological risk assessment approach integrating laboratory and in situ bioaccumulation and toxicity testing, passive sampler devices, hydrological characterization tools, continuous water quality sensing, and multi-phase chemical analyses was evaluated. The test site used to demonstrate the approach was a shallow estuarine wetland where groundwater seepage and elevated organic and inorganic contaminants were of potential concern. Although groundwater was discharging into the surficial sediments, little to no chemical contamination was associated with the infiltrating groundwater. Results from bulk chemistry analysis, toxicity testing, and bioaccumulation, however, suggested possible PAH toxicity at one station, which might have been enhanced by UV photoactivation, explaining the differences between in situ and laboratory amphipod survival. Concurrently deployed PAH bioaccumulation on solid-phase micro-extraction fibers positively correlated ( r 2 ≥ 0.977) with in situ PAH bioaccumulation in amphipods, attesting to their utility as biomimetics, and contributing to the overall improved linkage between exposure and effects demonstrated by this approach.

An approach for developing simple generic models for ecological risk assessments of fish populations

It has been argued that current approaches for ecological risk assessment (ERA) do not provide value relevance for risk managers and that the uncertainty in the predictions is large. One important reason for this is that current approaches are based on individual-level endpoints, but the environmental protection goals are defined on the population level. Population models may be useful tools to link the individual to the population and thus increase value relevance and reduce uncertainty. However, this requires that simple models and guidance on how to use them are made available for risk assessors. In the present study, an approach for developing simple generic models for the ERA of fish populations is presented. Fish have high ecological and economic value and are frequently used in ERA. It is, therefore, highly desirable to develop better methods for ERA of fish populations. The models were based on five types of life histories, and they were set up to be useful in a number of different management scenarios based on different environmental protection goals. A decision framework was set up for three levels of models (continuous, time limited, and varying exposure) and three levels of environmental protection. Data from previously published studies were tested for two of the environmental protection levels. The models provided maximum acceptable concentrations (MAC) that fell between the MACs of traditional ERA based on acute or chronic data, respectively.

Ecological Risk Assessment, Prediction, and Assessing Risk Predictions

Ecological risk assessment embodied in an adaptive management framework is becoming the global standard approach for formally assessing and managing the ecological risks of technology and development. Ensuring the continual improvement of ecological risk assessment approaches is partly achieved through the dissemination of not only the types of risk assessment approaches used, but also their efficacy. While there is an increasing body of literature describing the results of general comparisons between alternate risk assessment methods and models, there is a paucity of literature that post hoc assesses the performance of specific predictions based on an assessment of risk and the effectiveness of the particular model used to predict the risk. This is especially the case where risk assessments have been used to grant consent or approval for the construction of major infrastructure projects. While postconstruction environmental monitoring is increasingly commonplace, it is not common for a postconstruction assessment of the accuracy and performance of the ecological risk assessment and underpinning model to be undertaken. Without this "assessment of the assessment," it is difficult for other practitioners to gain insight into the performance of the approach and models used and therefore, as argued here, this limits the rate of improvement of risk assessment approaches.

Probabilistic ecological hazard assessment of microcystin-LR allelopathy to Prymnesium parvum

The harmful algal species Prymnesium parvum, a toxin-producing mixotrophic haptophyte, has caused massive fish kills in select inland Texas water bodies. Though P. parvum is present in a number of water bodies and Gulf of Mexico estuaries, it does not develop harmful blooms in all of them. A previous study by our team identified dissolved constituents from a cyanobacterial-dominated lake to exhibit concentration-dependent growth inhibition of P. parvum. Here we employed a probabilistic ecological risk assessment approach to examine the potential allelopathy of the cyanotoxin microcystin-LR (MC-LR) to P. parvum under laboratory conditions representative of Texas water bodies when blooms form. An environmental exposure distribution was constructed utilizing MC-LR concentrations detected in the environment and compared with experimental acute median lethal values reported in the literature. In a laboratory experiment, P. parvum cells were grown in media containing different MC-LR concentrations and cell density was determined daily. A concentration of 4392.8 µg L−1 significantly inhibited P. parvum growth over a portion of the study. Such a concentration was predicted to be detected or exceeded 9% of the time when microcystin producers are likely to occur. However, when a concentration this high occurs in the environment to affect P. parvum growth, a number of aquatic organisms may be expected to experience acute mortality from MC-LR. Further studies are warranted to define the effects of other compounds released by cyanobacteria on P. parvum populations.

Ecotoxicological assessment of diffuse pollution using biomonitoring tool for sustainable land use in Thailand

As a developing country, Thailand has a significant issue with diffuse pollution of the soil ecosystem due to an indiscriminate use of agrichemicals and poorly regulated disposal of a wide variety of hazardous wastes. Practical risk assessment tools based on locally-occurring species are needed to assess the effects of diffuse pollutants on the soil ecosystem in Thailand because reliance on soil criteria developed for overseas conditions may provide inadequate protection. Native soil organisms in Thailand may be more or less sensitive to contaminants compared to overseas test species. This article described a biological indicator approach for ecological risk assessment of diffuse pollution in the soil ecosystem of Thailand from pesticide application with the aim of developing standardized protocols using native species and locally generated data to better evaluate the ecological risks of non-point source soil pollution. It was found that ecotoxicological assessment provided a better understanding of the ecological impacts that diffuse pollution induced on Thai environmental conditions. Thai soil biota species were more sensitive to soil contaminants than similar species overseas. Soil series also had an influence on the ecotoxicology of contaminants to soil biota. Collembolan, Cyphoderus sp., was demonstrated as a useful alternative test species to Folsomia candida (international test species) for terrestrial ecotoxicological testing of Thai soils. In addition, the soil biota activities such as soil respiration and earthworm avoidance including soil biodiversity and the litter bag decomposition technique are also good tools to assess the effects of diffuse pollution by pesticides on the soil ecosystem of Thailand.

In situ‐based effects measures: Determining the ecological relevance of measured responses

The aim of this review is to examine how the choice of test species and study design employed in the use of in situ approaches in ecological risk assessment can maximize the ecological relevance of data. We provide a framework to define and assess ecological relevance that permits study designs to remain focused on the ecological question being addressed. This framework makes explicit the linkages between effects at lower levels of biological organization and higher-order ecological effects at the population, community, and ecosystem levels. The usefulness of this framework is illustrated by reference to specific examples from aquatic ecotoxicology. The use of models as both interpretive and predictive tools is discussed, with suggestions of appropriate methods for different protection goals.

Sequential analysis of lines of evidence—an advanced weight‐of‐evidence approach for ecological risk assessment

AbstractWeight‐of‐evidence (WOE) approaches have been used in ecological risk assessment (ERA) for many years. The approaches integrate various types of data (e.g., from chemistry, bioassay, and field studies) to make an overall conclusion of risk. However, the current practice of WOE has several important difficulties, including a lack of transparency related to how each line of evidence is weighted or integrated into the overall weight‐of‐evidence conclusion. Therefore, a sequential analysis of lines of evidence (SALE) approach has been developed that advances the practice of WOE. It was developed for an ERA of chemical stressors but also can be used for nonchemical stressors and is equally applicable to the aquatic and terrestrial environments. The sequential aspect of the SALE process is a significant advancement and is based on 2 primary ideas. First, risks can be ruled out with the use of certain lines of evidence, including modeled hazard quotients (HQs) and comparisons of soil, water, or sediment quality with conservative soil, water or sediment quality guidelines. Thus, the SALE process recognizes that HQs are most useful in ruling out risk rather than predicting risk to ecological populations or communities. Second, the SALE process provides several opportunities to exit the risk assessment process, not only when risks are ruled out, but also when magnitude of effect is acceptable or when little or no evidence exists that associations between stressors and effects may be causal. Thus, the SALE approach explicitly includes interaction between assessors and managers. It illustrates to risk managers how risk management can go beyond the simple derivation of risk‐based concentrations of chemicals of concern to risk management goals based on ecological metrics (e.g., species diversity). It also can be used to stimulate discussion of the limitations of the ERA science, and how scientists deal with uncertainty. It should assist risk managers by allowing their decisions to be based on a sequential, flexible, and transparent process that includes direct toxicity risks, indirect risks (via changes in habitat suitability), and the spatial and temporal factors that can influence the risk assessment.

Sequential Analysis of Lines of Evidence—An Advanced Weight-of-Evidence Approach for Ecological Risk Assessment

Weight-of-evidence (WOE) approaches have been used in ecological risk assessment (ERA) for many years. The approaches integrate various types of data (e.g., from chemistry, bioassay, and field studies) to make an overall conclusion of risk. However, the current practice of WOE has several important difficulties, including a lack of transparency related to how each line of evidence is weighted or integrated into the overall weight-of-evidence conclusion. Therefore, a sequential analysis of lines of evidence (SALE) approach has been developed that advances the practice of WOE. It was developed for an ERA of chemical stressors but also can be used for nonchemical stressors and is equally applicable to the aquatic and terrestrial environments. The sequential aspect of the SALE process is a significant advancement and is based on 2 primary ideas. First, risks can be ruled out with the use of certain lines of evidence, including modeled hazard quotients (HQs) and comparisons of soil, water, or sediment quality with conservative soil, water or sediment quality guidelines. Thus, the SALE process recognizes that HQs are most useful in ruling out risk rather than predicting risk to ecological populations or communities. Second, the SALE process provides several opportunities to exit the risk assessment process, not only when risks are ruled out, but also when magnitude of effect is acceptable or when little or no evidence exists that associations between stressors and effects may be causal. Thus, the SALE approach explicitly includes interaction between assessors and managers. It illustrates to risk managers how risk management can go beyond the simple derivation of risk-based concentrations of chemicals of concern to risk management goals based on ecological metrics (e.g., species diversity). It also can be used to stimulate discussion of the limitations of the ERA science, and how scientists deal with uncertainty. It should assist risk managers by allowing their decisions to be based on a sequential, flexible, and transparent process that includes direct toxicity risks, indirect risks (via changes in habitat suitability), and the spatial and temporal factors that can influence the risk assessment.

Ecological risk assessment issues identified during the U.S. environmental protection agency's examination of risk assessment practices

Recently, the U.S. Environmental Protection Agency examined its current risk-assessment principles and practices. As part of the examination, aspects of ecological risk-assessment practices were reviewed. Several issues related to ecological risk assessment were identified, including the use of organism-level versus population-level attributes to characterize risk, the possible opportunities associated with the increased use of probabilistic approaches for ecological risk assessment, and the notion of conservatism in estimating risks. The agency examination provides an understanding of current practices and is intended to begin a dialogue in which the risk assessment community can engage in addressing the identified issues to improve and enhance ecological risk assessment.

Toxicological constraints for rehabilitation of riverine habitats: a case study for metal contamination of floodplain soils along the Rhine.

Ambitious international action programmes and ecological rehabilitation projects have improved the environmental quality of riverine habitats along the Rhine branches in the Netherlands (rivers Waal, Neder-Rijn and IJssel). A major problem that remains to be solved is the contamination that over the last century has been accumulated in river sediments and deposits. Respectively, 65, 45 and 35 % of soil samples from floodplains along the rivers Waal, Neder-Rijn and IJssel exceed environmental quality standards for one or more contaminants (mainly metals). Storing or cleaning of contaminated sediments goes with high remediation costs and impedes ecological rehabilitation projects. Physical reconstruction measures may alter exposure of organisms to contaminants, e.g. by changing the bioavailability through transitions of terrestrial to aquatic habitats and vice versa. The question arises whether contaminants accumulated in river sediment and deposits will hinder the recovery of riverine biodiversity. The present paper gives an account of various approaches for ecological risk assessment of contaminated floodplain soils and focuses on effects of metal contamination (mainly cadmium) on riverine biodiversity. A weight of evidence approach reveals that invertebrates, small mammals and birds of prey are at risk due to metal exposure. Comparisons of measured and predicted cadmium concentrations in various species show that available models may overestimate as well as underestimate exposure risks. Site-specific exposure models should take into account spatial and temporal variability of exposure. GIS-based ecological risk assessment and site-specific risk maps offer river managers opportunities to delineate high-risk areas and to balance costs and ecological benefits of soil sanitation measures in river rehabilitation projects. New approaches to the remediation of floodplain soil contamination are briefly discussed.

Consideration of Background Radiation in Ecological Risk Assessments

Background or ambient concentrations are often considered in the evaluation of potential risks to ecological receptors from exposure to hazardous chemicals in the environment. Such an evaluation may be a component of the screening or final risk management process and sets the baseline from which risks contributed by site-related activities can be addressed. Although the process for the evaluation of potential radiological risks to ecological receptors is less formalized than the chemical hazard assessment process, background remains an issue that should be addressed when considering potential site-related impacts. This paper briefly presents the ecological risk assessment approaches used to address background radionuclide concentrations at three United States Department of Defense Facilities. The concepts of total radiation dose, and tolerance and adaptation of populations to radiation are also discussed within the context of background radiation.

New Approaches in Ecological Risk Assessment: Expanding Scales, Increasing Realism, and Enhancing Causal Analysis

New Approaches in Ecological Risk Assessment: Expanding Scales, Increasing Realism, and Enhancing Causal Analysis

Ecological risk to aquatic systems from salinity increases

Salinity is a major problem in many regions of Australia, and is predicted to get considerably worse over the next 30–50 years. Most effort has focused on the terrestrial environment, and specifically on the loss of productive agricultural land. Increased salinity can also result in unwanted changes to aquatic ecosystems in rivers, streams and particularly wetlands.This paper first reviews the importance of assessing risks from salinity increases in a catchment context, and then introduces a disturbance–response conceptual model to assist with the understanding of such situations. Two factors are shown to be particularly important in assessing which freshwater systems will be most susceptible to increases in salinity—the location of the systems in the landscape, and the current ecological condition of the system. The resilience of an ecosystem to salinity disturbances is shown to be a useful concept which with further knowledge may be incorporated into risk-assessment approaches.The development of a new ecological risk assessment approach for assessing risks to aquatic systems in the Goulburn–Broken catchment from increases in salinity over the medium (20 years) and long (100 years) term is reported. The risks to the biota in Hughes Creek, a tributary of the Goulburn River, are assessed by using a probabilistic approach. Current salinity levels in the creek present a low risk to the biota.Finally, the paper addresses the challenge of making the ecological risk assessment method more quantitative by discussing the following two key aspects: how to better quantify the linkages between the key stressors and the biotic components, and how to better handle uncertainties.

An Approach for Ecological Risk Assessment of Pesticides in Agriculture

An Approach for Ecological Risk Assessment of Pesticides in Agriculture

ECOLOGICAL CONSIDERATIONS IN BROWNFIELDS REDEVELOPMENT

ECOLOGICAL CONSIDERATIONS IN BROWNFIELDS REDEVELOPMENT