Methodology for conducting screening-level ecological risk assessments for hazardous waste sites. Part III: exposure and effects assessment

The Idaho National Engineering and Environmental Laboratory (INEEL) has implemented a phased approach to ecological risk assessment (ERA). The first step in this process is a screening-level ERA at each facility. Basic to this approach was the development of ecologically based screening levels (EBSLs), defined as concentrations of chemicals in soil (or other media) that are not expected to produce any adverse effects on selected ecological receptors under chronic exposure conditions (analogous to preliminary remediation goals or soil screening levels). EBSLs are calculated by rearrangement of standard exposure equations to solve for soil concentration when chemical intake rate is set at a developed toxicity reference value (TRV). A TRV is defined as a chronic dose that is likely to be without appreciable risk of deleterious effects. This definition was extended to define TRVs and ultimately EBSLs for the functional groups used in the INEEL screening-level ERAS.     

Methodology for conducting screening-level ecological risk assessments for hazardous waste sites. Part II: grouping ecological components

Screening-level ecological risk assessments are commonly conducted to identify those contaminants and receptors on which to focus future phases or tiers of the ecological risk assessment process. Most screening assessments are performed using a suite of individual species subjected to intensive evaluation of exposure (endpoint species) and selected for their appropriateness for serving as representatives or 'indicators' for all other species. As site complexity and the number of contaminants of concern increase, it becomes more difficult to assure with confidence that the potential for significant effects has been adequately assessed through an appropriate choice of endpoint species. As an alternative, functional groups demonstrating biological similarity and similar potential for contaminant exposure were developed for INEEL screening-level ecological risk assessments using taxonomic, trophic and habitat parameters. Data for individual species within each group are then integrated to address the potential for risk of adverse effects from contaminant exposure for the group as a whole.     

Using a probabilistic approach in an ecological risk assessment simulation tool: test case for depleted uranium (DU)

A probabilistic approach was applied in an ecological risk assessment (ERA) to characterize risk and address uncertainty employing Monte Carlo simulations for assessing parameter and risk probabilistic distributions. This simulation tool (ERA) includes a Window's based interface, an interactive and modifiable database management system (DBMS) that addresses a food web at trophic levels, and a comprehensive evaluation of exposure pathways. To illustrate this model, ecological risks from depleted uranium (DU) exposure at the US Army Yuma Proving Ground (YPG) and Aberdeen Proving Ground (APG) were assessed and characterized. Probabilistic distributions showed that at YPG, a reduction in plant root weight is considered likely to occur (98% likelihood) from exposure to DU; for most terrestrial animals, likelihood for adverse reproduction effects ranges from 0.1% to 44%. However, for the lesser long-nosed bat, the effects are expected to occur (>99% likelihood) through the reduction in size and weight of offspring. Based on available DU data for the firing range at APG, DU uptake will not likely affect survival of aquatic plants and animals (<0.1% likelihood). Based on field and laboratory studies conducted at APG and YPG on pocket mice, kangaroo rat, white-throated woodrat, deer, and milfoil, body burden concentrations observed fall into the distributions simulated at both sites.     

Micro-evolution due to pollution: possible consequences for ecosystem responses to toxic stress

Polluting events can change community structure and ecosystem functioning. Selection of genetically inherited tolerance on exposed populations, here referred as micro-evolution due to pollution, has been recognized as one of the causes of these changes. However, there is a gap between studies addressing this process and those assessing effects at higher levels of biological organization. In this review we attempt to address these evolutionary considerations into the ecological risk assessment (ERA) of polluting events and to trigger the discussion about the consequences of this process for the ecosystem response to toxic stress. We provide clear evidence that pollution drives micro-evolutionary processes in several species. When this process occurs, populations inhabiting environments that become polluted may persist. However, due to the existence of ecological costs derived from the loss of genetic variability, negative pleiotropy with fitness traits and/or from physiological alterations, micro-evolution due to pollution may alter different properties of the affected populations. Despite the existence of empirical evidence showing that safety margins currently applied in the ERA process may account for pollution-induced genetic changes in tolerance, information regarding long-term ecological consequences at higher levels of biological organization due to ecological costs is not explicitly considered in these procedures. In relation to this, we present four testable hypotheses considering that micro-evolution due to pollution acts upon the variability of functional response traits of the exposed populations and generates changes on their functional effect traits, therefore, modifying the way species exploit their ecological niches and participate in the overall ecosystem functioning.     

A tiered ecological risk assessment of three chlorophenols in Chinese surface waters

Introduction

The ecological risks posed by three chlorophenols (CPs), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) in Chinese surface waters were assessed.

Materials and methods

This was achieved by applying a tiered ecological risk assessment (ERA) approach ranging from deterministic methods to probabilistic options to measured concentrations of CPs in surface water of seven major watersheds and three drainage regions in China and the chronic toxicity data for indigenous Chinese species.

Results and discussion

The results show that the risks of three chlorophenols are ranked PCP>2,4-DCP??2,4,6-TCP. PCP posed little ecological risk while 2,4-DCP and 2,4,6-TCP posed negligible or de minimis risk in Chinese surface water. However, the risks varied with different river basins, for example, PCP posed some ecological risk in the Yangtze, Huaihe, and Pearl Rivers. The magnitude of 2,4-DCP and 2,4,6-TCP pollution in North China was more serious than that in South China.

Conclusion

The probabilistic risk assessment approach, which can provide more information for risk managers and decision makers, was favored over the screening-level single-value estimate method. However, the results from all tiers of the ERA methods in the framework were consistent with each other.     

Screening-level ecological risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments and aquatic biota from the Venice Lagoon, Italy

Recent monitoring data indicate that portions of Italy's Venice Lagoon ecosystem have been degraded due to biological and chemical pollution from a variety of potential sources. Using polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) data collected from sediment, fish and shellfish in the Lagoon, a screening-level ecological risk assessment (ERA) was performed to evaluate the risks to representative aquatic biota and wildlife receptors. Risks to aquatic invertebrates posed by PCDD/Fs in sediment were evaluated by comparing measured tissue concentrations in fish and shellfish to appropriate ecotoxicological reference values. For mammalian and avian receptors, risks posed by theoretical exposures to PCDD/Fs through the food chain were calculated using conservative wildlife exposure models. Results of the screening-level approach indicate that the potential for adverse effects to fish and aquatic invertebrate receptors from PCDD/Fs in surficial sediments are unlikely. Adverse effects to wildlife are possible but highly uncertain, and warrants further investigation in a more comprehensive ERA.     

Accounting for both local aquatic community composition and bioavailability in setting site-specific quality standards for zinc

Recent years have seen considerable improvement in water quality standards (QS) for metals by taking account of the effect of local water chemistry conditions on their bioavailability. We describe preliminary efforts to further refine water quality standards, by taking account of the composition of the local ecological community (the ultimate protection objective) in addition to bioavailability. Relevance of QS to the local ecological community is critical as it is important to minimise instances where quality classification using QS does not reconcile with a quality classification based on an assessment of the composition of the local ecology (e.g. using benthic macroinvertebrate quality assessment metrics such as River InVertebrate Prediction and Classification System (RIVPACS)), particularly where ecology is assessed to be at good or better status, whilst chemical quality is determined to be failing relevant standards. The alternative approach outlined here describes a method to derive a site-specific species sensitivity distribution (SSD) based on the ecological community which is expected to be present at the site in the absence of anthropogenic pressures (reference conditions). The method combines a conventional laboratory ecotoxicity dataset normalised for bioavailability with field measurements of the response of benthic macroinvertebrate abundance to chemical exposure. Site-specific QS_ref are then derived from the 5%ile of this SSD. Using this method, site QS_ref have been derived for zinc in an area impacted by historic mining activities. Application of QS_ref can result in greater agreement between chemical and ecological metrics of environmental quality compared with the use of either conventional (QS_con) or bioavailability-based QS (QS_bio). In addition to zinc, the approach is likely to be applicable to other metals and possibly other types of chemical stressors (e.g. pesticides). However, the methodology for deriving site-specific targets requires additional development and validation before they can be robustly applied during surface water classification.     

Evaluation of near surface ozone in air quality simulations forced by a regional climate model over Europe for the period 1991–2000

This study aims to evaluate near surface ozone simulated with the modelling system RegCM3/CAMx against ozone measurements from the EMEP database for the recent decade 1991–2000. The RegCM3/CAMx simulations were performed on a 50 km × 50 km grid over Europe driven either by ERA-40 reanalysis (hereafter referred as ERA simulation) or the global circulation model (GCM) ECHAM5 (hereafter referred as ECHAM simulation). A set of statistical metrics is used for the model evaluation, including temporal correlation coefficient, the ratio of the standard deviations and the bias of simulated versus observed values. Overall, a good agreement is found for both ERA and ECHAM simulations at the majority of the selected EMEP stations in all metrics throughout the year based either on monthly or daily ozone values. Based on these results, it is assessed that the modelling system RegCM3/CAMx is suitable to be used for present and future regional climate-air quality simulations with emphasis on near surface ozone. The ERA simulations reproduce more accurately the observed ozone values in comparison to ECHAM simulations because the meteorology of the ERA experiment is closer to real atmospheric conditions than the GCM based experiment. On a seasonal basis, both ERA and ECHAM simulations exhibit a seasonally dependent bias, with winter and spring ozone values being generally under-estimated by the model and summer and autumn values being slightly overestimated. This seasonally dependent bias is also evident from median and peak midday ozone values. However, the highest observed midday ozone peaks in summer, with values higher than 80 ppbv, could not be captured either by ERA or ECHAM simulations. An analysis of day-time and night-time ERA and ECHAM modelled ozone values shows that CAMx performs better during the day-time.     

A review of models for estimating terrestrial ecological receptor exposure to chemical contaminants

In instances where empirical measurements are not practicable, ecological risk assessments may rely on site-specific exposure models for estimating uptake of chemical contaminants. This paper presents, based on a review of the literature, a compilation of relatively simple quantitative models that can be combined to produce site- and species-specific first-order estimates of uptake of chemicals from abiotic media. These models have proved useful in providing order-of-magnitude estimates for screening and sample program design purposes. This paper intended as both a practical guide for choosing models to estimate terrestrial wildlife exposures and as a step toward development of a more comprehensive and standard approach to exposure assessment in terrestrial ecological receptors.     

Rodent sperm analysis in field-based ecological risk assessment: pilot study at Ravenna army ammunition plant,Ravenna, Ohio

Ecological risk assessment (ERA) guidance recommends that field-truthing efforts proceed when modeled hazard quotients (HQs) suggest that toxicological effects are occurring to site receptors. To date, no field methods have been proposed by the regulatory community that can lead to definitive determinations of acceptable or unacceptable risk for birds and mammals, the two terrestrial classes of receptors that are commonly assessed using the HQ method. This paper describes rodent sperm analysis (RSA) as a viable method to be applied in the field at sites with historical contamination. RSA is capable of detecting biological differences that bear on reproduction, a highly regarded toxicological endpoint of concern in USEPA Superfund-type ERAs. The results of RSA's first application at a study site are reported and discussed. The paper also provides the rationale for RSA's efficacy in the context of Superfund and other environmental cleanup programs, where limited time and money are available to determine and evaluate the field condition.     

Development of Cleanup Standards at Superfund Sites: An Evaluation of Consistency

The Washington Department of Ecology (WDOE) recently developed a regulatory program for determining cleanup standards at hazardous waste sites. One of WDOE's first tasks in the development of a cleanup standards program was to evaluate how standards have been developed and implemented under Superfund.

The evaluation of cleanup standards revealed: (1) a great deal of variation among sites, both in the magnitude of the standards set for some contaminants and the basis on which they were set, and (2) that there is no consistent decision-making approach for determining how standards should be set. This lack of consistency and guidance has the potential to result in overly stringent or underprotective cleanup requirements and inefficient standard development.

Washington State has adopted an approach that allows for implementing uniform numerical cleanup standards at relatively straightforward sites and provides a process for establishing site-specific cleanup levels at more complex sites. This approach is expected to facilitate development of standards that offer appropriate human health and ecological protection while minimizing private and public sector site management and cleanup costs.     

A method of assessing air toxics concentrations in urban areas using mobile platform measurements

The objective of this paper is to demonstrate an approach to characterize the spatial variability in ambient air concentrations using mobile platform measurements. This approach may be useful for air toxics assessments in Environmental Justice applications, epidemiological studies, and environmental health risk assessments. In this study, we developed and applied a method to characterize air toxics concentrations in urban areas using results of the recently conducted field study in Wilmington, DE. Mobile measurements were collected over a 4- x 4-km area of downtown Wilmington for three components: formaldehyde (representative of volatile organic compounds and also photochemically reactive pollutants), aerosol size distribution (representing fine particulate matter), and water-soluble hexavalent chromium (representative of toxic metals). These measurements were,used to construct spatial and temporal distributions of air toxics in the area that show a very strong temporal variability, both diurnally and seasonally. An analysis of spatial variability indicates that all pollutants varied significantly by location, which suggests potential impact of local sources. From the comparison with measurements at the central monitoring site, we conclude that formaldehyde and fine particulates show a positive correlation with temperature, which could also be the reason that photochemically generated formaldehyde and fine particulates over the study area correlate well with the fine particulate matter measured at the central site.     

Why a Global International Waters Assessment (GIWA)?

Why GIWA? Six years ago several people had their doubts as to whether a Global International Waters Assessment would be worth the money and effort. Nowadays, it is no longer necessary to justify the creation of GIWA. On the contrary, we will show how important it was that the Global Environmental Facility (GEF) and UNEP, constituted GIWA. Countless water-related assessments focus on specific regions and/or specific issues. But GIWA is unique in its global and holistic policy-oriented approach applying a common methodology to address the major problems in all parts of the global hydrosphere. One major achievement of GIWA will be the GIWA publications which provide advice to GEF and other decision-making organizations. Further assets include the network of regional focal points and teams. GIWA encompasses marine, surface freshwater, and groundwater systems, following the flow of water from the sources in the mountains through the rivers and estuaries into the coastal waters and the shelf seas. GIWA studies the physical, chemical and biological properties of those waterbodies and living resources in relation to the human activities, combining ecological and socioeconomic considerations.     

A socio-ecological adaptive approach to contaminated mega-site management: from 'control and correct' to 'coping with change'

Mega-sites have a notable impact on surrounding ecological systems. At such sites there are substantial risks associated with complex socio-ecological interactions that are hard to characterize, let alone model and predict. While the urge to control and clean-up mega-sites (control and correct) is understandable, rather than setting a goal of cleaning up such sites, we suggest a more realistic response strategy is to address these massive and persistent sources of contamination by acknowledging their position as new features of the socio-ecological landscapes within which they are located. As it seems nearly impossible to clean up such sites, we argue for consideration of a 'coping with change' rather than a 'control and correct' approach. This strategy recognizes that the current management option for a mega-site, in light of its physical complexities and due to changing societal preferences, geochemical transformations, hydrogeology knowledge and remedial technology options may not remain optimal in future, and therefore needs to be continuously adapted, as community, ecology, technology and understanding change over time. This approach creates an opportunity to consider the relationship between a mega-site and its human and ecological environments in a different and more dynamic way. Our proposed approach relies on iterative adaptive management to incorporate mega-site management into the overall socio-ecological systems of the site's context. This approach effectively embeds mega-site management planning in a triple bottom line and environmental sustainability structure, rather than simply using single measures of success, such as contaminant-based guidelines. Recognizing that there is probably no best solution for managing a mega-site, we present a starting point for engaging constructively with this seemingly intractable issue. Therefore, we aim to initiate discussion about a new approach to mega-site management, in which the complexity of the problems posed by mega-sites is reflected upon in its entirety. These complexities are associated with uncertainties and unknowns that have to be addressed, as they have an impact on the strategies being developed and applied. We contend that the best that can be hoped for in mega-site management is an acceptable solution for the current state of affairs, with good flexibility to modify strategies as new site conditions, remediation possibilities, community preferences and management objectives develop over time.     

Development and implementation of eco-genomic tools for aquatic ecosystem biomonitoring: the SYNAQUA French-Swiss program

The effectiveness of environmental protection measures is based on the early identification and diagnosis of anthropogenic pressures. Similarly, restoration actions require precise monitoring of changes in the ecological quality of ecosystems, in order to highlight their effectiveness. Monitoring the ecological quality relies on bioindicators, which are organisms revealing the pressures exerted on the environment through the composition of their communities. Their implementation, based on the morphological identification of species, is expensive because it requires time and experts in taxonomy. Recent genomic tools should provide access to reliable and high-throughput environmental monitoring by directly inferring the composition of bioindicators’ communities from their DNA (metabarcoding). The French-Swiss program SYNAQUA (INTERREG France-Switzerland 2017–2019) proposes to use and validate the tools of environmental genomic for biomonitoring and aims ultimately at their implementation in the regulatory bio-surveillance. SYNAQUA will test the metabarcoding approach focusing on two bioindicators, diatoms, and aquatic oligochaetes, which are used in freshwater biomonitoring in France and Switzerland. To go towards the renewal of current biomonitoring practices, SYNAQUA will (1) bring together different actors: scientists, environmental managers, consulting firms, and biotechnological companies, (2) apply this approach on a large scale to demonstrate its relevance, (3) propose robust and reliable tools, and (4) raise public awareness and train the various actors likely to use these new tools. Biomonitoring approaches based on such environmental genomic tools should address the European need for reliable, higher-throughput monitoring to improve the protection of aquatic environments under multiple pressures, guide their restoration, and follow their evolution.     

Hazard prioritization in ecological risk assessment through spatial analysis of toxicant gradients

The analysis of spatial relationships among the distribution of environmental stressors and observed or predicted adverse effects may be a useful method of prioritizing hazards in regional ecological risk assessment (ERA). Geographic information systems were used to compare the spatial distribution of toxicant concentrations in sediments of Chesapeake Bay with the distribution of areas in the basin where ecological impacts have historically been observed. Toxicants were then prioritized based upon the strength of their spatial association with the high impact areas. This method of hazard identification/prioritization was validated against the Chesapeake Bay Program's lists of toxics of concern and toxics of potential concern (TOC and TOPC, respectively). Of the 18 toxicants on the TOC/TOPC lists that were considered in the current study, 15 (83%) were identified as priority contaminants in the current study, 11 (73%) of which were either of primary or secondary concern. The use of spatial analysis tools in ERA may lead to more rapid and rigorous methods for prioritizing environmental risks.     

The ChimERA project: coupling mechanistic exposure and effect models into an integrated platform for ecological risk assessment

Current techniques for the ecological risk assessment of chemical substances are often criticised for their lack of environmental realism, ecological relevance and methodological accuracy. ChimERA is a 3-year project (2013–2016), funded by Cefic’s Long Range Initiative (LRI) that aims to address some of these concerns by developing and testing mechanistic fate and effect models, and coupling of these models into one integrated platform for risk assessment. This paper discusses the backdrop against which this project was initiated and lists its objectives and planned methodology.     

Ecological risk assessments of endocrine disrupting organotin compounds using marine neogastropods in Hong Kong

As active ingredients of anti-fouling paints that are widely used on ship hulls, organotin compounds, in particular tributyltin (TBT), are well-known endocrine disruptors causing sex changes in marine organisms and widespread in coastal waters and sediments worldwide. In this study, a comprehensive ecological risk assessment (ERA) of organotins was conducted in Hong Kong waters through determining the imposex status, sex ratio and tissue burdens of these compounds in the neogastropods, Thais clavigera and Thais luteostoma collected from 29 coastal sites. We also investigated the historical trend of organotin effects on these gastropods, and performed a probabilistic ERA based on tissue burden of TBT in the animals. Our results demonstrated that imposex indices were positively correlated with the body burden of organotins in the gastropods. Across all sites, the sex ratio (female:male) decreased significantly with increasing imposex levels or tissue burden of organotins, implying that such pollutants can result in a male-biased population, potentially leading to local extinction in extreme cases. Based on the ERA, 5.4% of all populations of T. clavigera are at risk due to exposure to TBT; the risks include growth inhibition, impairment of immune functions and reduced fitness. Seriously impacted areas included Aberdeen, Repulse Bay, Butterfly Beach, Mui Wo and Ha Mei Wan. A comparison with historical data revealed that there had been some improvement in the areas with low marine traffic, and distant from the major harbour/port. This could partly be due to the restriction on the use of TBT on small vessels (<25m in length) since 1992. Nevertheless, the organotin contamination still remains severe in areas with high marine traffic or adjacent to large harbours/ports. In particular, the situation in the northeastern waters of Hong Kong has been getting worst since 1996 that is probably associated with the rapid development of the cargo container port at Yantian in China.     

HCH contamination from former pesticide production in Brazil—a challenge for the Stockholm Convention implementation

Hexachlorocyclohexane (HCH) isomers (α-, β- and γ- HCH [lindane]) were recently added to the list of persistent organic pollutants regulated by the Stockholm Convention, and therefore, the legacy of HCH and lindane production has become an issue of global relevance. The production of lindane with the much larger quantities of associated waste isomers has generated large waste deposits and contaminated sites. This article presents an overview of HCH-polluted sites in Brazil as a basis for further activities related to the Stockholm Convention. The locations of HCH stockpiles and contaminated sites in Brazil arising from production and formulation have been compiled and mapped. This shows that the measures taken over the past 25 years have not resulted in remediation of the HCH pollution. An exposure risk study has been summarised for one major site and is included to demonstrate the contemporary relevance of the contamination. Major site remediation efforts are planned at one site but people live close to several other sites, and there is an urgent need of further assessments and remediation to ensure the protection of human health and the environment. The Stockholm Convention requires a systematic approach and should be adopted for the assessment of all sites and appropriate isolation/remediation measures should be facilitated. The appropriate planning of these activities for the production site in Rio de Janeiro could be a positive contribution for Rio+20 highlighting that green economy and sustainable production also include the appropriate management of legacies of historic production of an industrial sector (here the organochlorine industry).     

A simple semi-empirical model for predicting missing carbon monoxide concentrations

Carbon monoxide monitoring using continuous samplers is carried out in most major urban centres in the world and generally forms the basis for air quality assessments. Such assessments become less reliable as the proportion of data missing due to equipment failure and periods of calibration increases. This paper presents a semi-empirical model for the prediction of atmospheric carbon monoxide concentrations near roads for the purpose of interpolating missing data without the need for any traffic or emissions information. The model produces reliable predictions while remaining computationally simple by being site-specifically optimized. The model was developed for, and evaluated at, both a suburban site and an inner city site in Hamilton, New Zealand. Model performance statistics were found to be significantly better than other simple methods of interpolation with little additional computational complexity.