Ecological Receptors Research Articles

Ecological risk assessment of perfluooroctane sulfonate to aquatic fauna from a bayou adjacent to former fire training areas at a US Air Force installation.

Per- and polyfluoroalkyl substances (PFASs) continue to receive significant attention, with particular concern for PFASs such as perfluorooctane sulfonate (PFOS), which was a constituent of aqueous film-forming foam used widely as a fire suppressant for aircraft since the 1970s. We were interested in the potential for risk to ecological receptors inhabiting Cooper Bayou, which is adjacent to 2 former fire-training areas at Barksdale Air Force Base (LA, USA). Previous research showed higher PFOS concentrations in surface water and biota from Cooper Bayou compared to reference sites. To estimate risk, we compared surface water concentrations from multiple sites within Cooper Bayou with several PFOS chronic toxicity benchmarks for freshwater aquatic organisms (∼0.4-5.1 μg PFOS/L) and showed probability of exceedances from 0.04 to 0.5, suggesting a potential for adverse effects in the most contaminated habitats. A tissue-residue assessment similarly showed some exceedance of benchmarks but with a lower probability (maximum = 0.17). Both fire-training areas have been inactive for more than a decade, so exposures (and, thus, risks) are expected to decline. Several uncertainties limit confidence in our risk estimates including highly dynamic surface water concentrations and limited chronic toxicity data for relevant species. Also, we have little data concerning organisms higher in the food chain which may receive higher lifetime exposures given the potential for PFOS to bioaccumulate and the longevity of many of these organisms. Overall, the present study suggests that PFOS can occur at concentrations that may cause adverse effects to ecological receptors, although additional, focused research is needed to reduce uncertainties. Environ Toxicol Chem 2018;37:2198-2209. © 2018 SETAC.

The biologically active zone in upland habitats at the Hanford Site, Washington, USA: Focus on plant rooting depth and biomobilization.

We challenge the suggestion by Sample et al. (2015) that a depth of 305 cm (10 ft) exceeds the depth of biological activity in soils at the Hanford Site, Washington, USA, or similar sites. Instead, we support the standard point of compliance, identified in the Model Toxics Control Act in the state of Washington, which specifies a depth of 457 cm (15 ft) for the protection of both human and ecological receptors at the Hanford Site. Our position is based on additional information considered in our expanded review of the literature, the influence of a changing environment over time, plant community dynamics at the Hanford Site, and inherent uncertainty in the Sample et al. (2015) analysis. Integr Environ Assess Manag 2018;14:442-446. © 2018 SETAC.

Petroleum Hydrocarbons Contamination of Surface Water and Groundwater in the Niger Delta Region of Nigeria

Petroleum hydrocarbons contamination of the environment associated with exploration, development and production operations is a common feature in oil producing nations around the world, especially in a developing country like Nigeria where the incidence of facilities sabotage, operational failures, accidental discharges, pipeline vandalization and leakages, bunkering and artisanal refining is very common. Apart from poor governance systems, poor corporate social responsibility (CSR) of multinational oil companies (MOCs), poor environmental regulation of the petroleum industry, the inability of the political elite to effectively manage petroleum hydrocarbon-derived revenue, loss of petroleum hydrocarbons resource revenue to corruption and theft, petroleum hydrocarbons contamination of the total environment (air, soil, water and biota) have impacted negatively on the human health and wellbeing of oil producing communities in the Nigeria’s Niger Delta region. Findings from several studies have revealed variable negative impacts of petroleum hydrocarbons toxicity on the human health (including exposed populations), the natural environment and other ecological receptors. Over the past fifty–five years, the oil producing host communities in the Nigeria’s Niger Delta region have experienced a wide range of environmental pollution, degradation, human health risks, deterioration of our cultural heritage items and socio–economic problems as a result of various activities associated with petroleum exploration, development and production. Petroleum hydrocarbons contamination of surface water and groundwater is a notable environmental and human health problem in the oil producing communities and there are several water quality issues in the Nigeria’s Niger Delta region. This review examines some of the water quality issues and human health implications of petroleum hydrocarbons contamination of controlled water sources (surface-water and groundwater) in the oil producing host communities in the Nigeria’s Niger Delta region. It will further highlight some of the problems of petroleum hydrocarbons contamination and/or pollution of marine environments associated with unsustainable practices of petroleum industry in the region.

The exploration of essential theories about regional ecology

With the integration of regional development, regional ecological environment problems are becoming more and more severe, which has attracted extensive attention of researchers. Therefore, the 589th XiangShan Science Conference was organized to discuss how to build the regional ecology disciplinary system, and how to solve the current outstanding regional environment problems. It was agreed that regional ecological protection theory has characteristics of the current times and practical value, and the construction of regional ecological discipline is imperative. Based on the features of regional ecological problems, this paper puts forward three core theories of regional ecological protection. Firstly, the theory of “the dual coupling of ecological donor-ecological receptor”, which refers to the dual relationship of the land-land coupling and human-land coupling, are based on the ecological donor and the ecological acceptor. Land-land coupling indicates the coupling of ecological donor and receptor on space in the ecological domain, and the interdependence level between the donor and receptor determines healthy development and the ecological integrity of the ecological domain; human-land coupling refers to the coupling of the economic social system and natural ecological system in the ecological domain, and the suitability of human living environment and industries determines the degree of human-land coupling in the ecological-economic system. The second theory is the “triune theory of ecological pattern-process-function”. It was argued that the pattern is the carrier of the process, and the change of pattern leads to the change of ecological process. Process is the motivation and the driving force in forming pattern, and pattern will also respond to the change of process. The interaction of ecological pattern and process will show different ecological functions. Therefore, they are mutually affected and are reciprocal causation for each other. The regional coordinated development and ecological security can only be realized by integrated pattern, continuous process and matching function between the ecological donor and receptor. The third theory is “the suitable relationship between ecological biological capacity and regional development”, which is based on the suitability among human settlements, industrial structure, distribution, scale and natural resources & environment. Therefore, the maintenance and improvement of the ecological carrying capacity has direct effect on the sustainable development of the whole ecological domain. The economic and social development in the ecological domain must be appropriate with its ecological carrying capacity in order to realize the coordination of human-land system. From the view of the interaction among the ecological donors, ecological receptors, and ecological medium in the ecological domain, regional ecology analyzes ecological pattern, process and function in the ecological domain, and emphasizes the coupling of ecological carrying capacity as well as natural, economic and social factors. Three core-theory system is the fundamental solution to solve the land-land and human-land coordination problems, and the research results will play an important role in guiding the construction of regional ecological security pattern and space optimization, regional ecological protection and improvement of ecological service function, protection and repair technologies of regional ecological governance, as well as the optimization of regional industrial structure and distribution, etc. This theory provides new epistemology and methodology for solving current regional environmental problems.

Environmental risks posed by heavy metal contamination from mine waste: Case study from northwest Iran

ABSTRACTMining activities produce waste tailings that can be a significant source of pollution in the surrounding ecosystem. This study was designed to estimate the magnitude of Fe, As, Pb, Cd, Mn, Ni, Zn, and Cr in soil impacted by activities in the Moeil iron ore mine area of northwestern Iran and initially assess the potential risk to nearby residents and ecological habitats. For this, concentrations of elements in 24 samples from 8 locations were analyzed by inductivity coupled plasma optical emission spectrometry. Concentrations of heavy metals reported for samples collected from the area ranged from 50,247–466,200 mg/kg for Fe, 40–10,827 mg/kg for As, 9–84 mg/kg for Pb, 0.2–58.4 mg/kg for Cd, 32–424 mg/kg for Mn, 4–32 mg/kg for Ni, 37–60 mg/kg for Zn, and 32–337 mg/kg for Cr. Reported levels of Fe and As in particular are indicative of severe contamination and imply a high risk to ecological receptors. Reported levels of arsenic also imply elevated cancer and non-cancer health risks to residents who work in or pass through the area. Reported levels of Cd and Cr in soil samples also indicate an elevated cancer risk posed by these metals. The result of this study indicates it is important to estimate potential contamination of soils and drinking water wills in the vicinity of Moeil village to arsenic and heavy metals.

Green Algae as Carriers Enhance the Bioavailability of 14C-Labeled Few-Layer Graphene to Freshwater Snails.

The waterborne exposure of graphene to ecological receptors has received much attention; however, little is known about the contribution of food to the bioaccumulation potential of graphene. We investigated the effect of algal food on the uptake and distribution of 14C-labeled few-layer graphene (FLG) in freshwater snails, a favorite food for Asian people. In a water-only system, FLG (∼158 μg/L) was ingested by and accumulated in the snails. Adding algae to the water significantly enhanced FLG accumulation in the snails, with a bioaccumulation factor of 2.7 (48 h exposure). Approximately 92.5% of the accumulated FLG was retained in the intestine; in particular, the accumulated FLG in the intestine was able to pass through the intestinal wall and enter the intestinal epithelial cells. Of them, 1.3% was subsequently transferred/internalized to the liver/hepatocytes, a process that was not observed in the absence of the algae. Characterizations data further suggested that both of the extra- and intracellular FLG in the algae (the algae-bound fraction was 30.2%) significantly contributed to the bioaccumulation. Our results provide the first evidence that algae as carriers enhanced FLG bioavailability to the snails, as well as the potential of FLG exposure to human beings through consuming the contaminated snails.

Trophic transfer of citrate, PVP coated silver nanomaterials, and silver ions in a paddy microcosm.

We used replicated paddy microcosm systems to estimate the tropic transfer of citrate-coated silver nanoparticles (AgNP citrate), polyvinylpyrrolidone (PVP)-coated AgNP (AgNP PVP), and silver ions (AgNO3) for 14 days under two exposure regimes (a single high-dose exposure; 60 μg L-1 and a sequential low-dose exposure at 1 h, 4 days and 9 days; 20 μg L-1 × 3 = 60 μg L-1). Most Ag ions from AgNO3 had dispersed in the water and precipitated partly on the sediment, whereas the two Ag NPs rapidly coagulated and precipitated on the sediment. The bioconcentration factors (BCFs) of Ag from AgNPs and AgNO3 in Chinese muddy loaches and biofilms were higher than those of river snails in both exposure conditions. These BCFs were more prominent for 14 days exposure (7.30 for Chinese muddy loach; 4.48 for biofilm) in the low-dose group than in the single high-dose group. Their retention of AgNPs and Ag ions differed between the two exposure conditions, and uptake and elimination kinetics of Ag significantly differed between AgNP citrate and AgNP PVP in the sequential low-dose exposure. Stable isotopes analyses indicated that the trophic levels between Chinese muddy loaches and biofilms and between river snails and biofilms were 2.37 and 2.27, respectively. The biomagnification factors (BMFs) of AgNPs and AgNO3 between Chinese muddy loaches and biofilms were significantly higher than those between river snails and biofilms under both exposure settings. The BMFs of AgNP citrate and AgNO3 between Chinese muddy loaches and biofilms were greater than those of AgNP PVP for 14 days in the single high-dose group, whereas the BMFs of AgNP PVP were greater than those of AgNP citrate and AgNO3 in the sequential low-dose group. These microcosm data suggest that AgNPs have the potential to impact on ecological receptors and food chains.

Empirically-based modeling and mapping to consider the co-occurrence of ecological receptors and stressors

Part of the ecological risk assessment process involves examining the potential for environmental stressors and ecological receptors to co-occur across a landscape. In this study, we introduce a Bayesian joint modeling framework for use in evaluating and mapping the co-occurrence of stressors and receptors using empirical data, open-source statistical software, and Geographic Information Systems tools and data. To illustrate the approach, we apply the framework to bioassessment data on stream fishes and nutrients collected from a watershed in southwestern Ohio. The results highlighted the joint model's ability to parse and exploit statistical dependencies in order to provide empirical insight into the potential environmental and ecotoxicological interactions influencing co-occurrence. We also demonstrate how probabilistic predictions can be generated and mapped to visualize spatial patterns in co-occurrences. For practitioners, we believe that this data-driven approach to modeling and mapping co-occurrence can lead to more quantitatively transparent and robust assessments of ecological risk.

Assessing Risks at a Former Chemical Facility, Nanjing City, China: An Early Test of the New Remediation Guidelines for Waste Sites in China

China has recognized the need to investigate and remediate former manufacturing facilities and return the land they occupy to a new, productive use. As a result, national guidelines entitled “Technical guidelines for Risk assessment of contaminated sites” were issued in 2014 to guide site investigations, risk assessments, and remedial actions to reduce or mitigate potential exposures of people and ecological receptors to contaminants. This study was pursued to gain experience with the new guidelines at a small, former chemical manufacturing facility in Nanjing City, China. A series of investigations were undertaken to determine the locations and levels of contaminants in soils and groundwater, develop a conceptual site model, and prepare an initial estimate of risks to humans and ecological receptors. Groundwater results revealed several contaminants that were greater than the Dutch Intervention Levels, yet, surprisingly, few, if any, contaminants were found in multiple samplings of soil. Despite the limited investigations of soil and groundwater, data were sufficient to prepare initial risk evaluations for humans, both for systemic toxins and potentially carcinogenic chemicals. The site and nearby area contain industrial facilities and residential neighborhoods; hence, there were too few ecological receptors to warrant an ecological risk assessment. The new guidelines for site investigations and risk assessments proved sufficient for the purposes of this small site; however, more complex sites may require much greater levels of effort and more detailed guidelines for investigations, risk assessments, and remedial actions.

Potential ecological risk assessment and predicting zinc accumulation in soils

The aims of this study were to investigate zinc content in the studied soils; evaluate the efficiency of geostatistics in presenting spatial variability of zinc in the soils; assess bioavailable forms of zinc in the soils and to assess soil–zinc binding ability; and to estimate the potential ecological risk of zinc in soils. The study was conducted in southern Poland, in the Malopolska Province. This area is characterized by a great diversity of geological structures and types of land use and intensity of industrial development. The zinc content was affected by soil factors, and the type of land use (arable lands, grasslands, forests, wastelands). A total of 320 soil samples were characterized in terms of physicochemical properties (texture, pH, organic C content, total and available Zn content). Based on the obtained data, assessment of the ecological risk of zinc was conducted using two methods: potential ecological risk index and hazard quotient. Total Zn content in the soils ranged from 8.27 to 7221 mg kg−1 d.m. Based on the surface semivariograms, the highest variability of zinc in the soils was observed from northwest to southeast. The point sources of Zn contamination were located in the northwestern part of the area, near the mining–metallurgical activity involving processing of zinc and lead ores. These findings were confirmed by the arrangement of semivariogram surfaces and bivariate Moran’s correlation coefficients. The content of bioavailable forms of zinc was between 0.05 and 46.19 mg kg−1 d.m. (0.01 mol dm−3 CaCl2), and between 0.03 and 71.54 mg kg−1 d.m. (1 mol dm−3 NH4NO3). Forest soils had the highest zinc solubility, followed by arable land, grassland and wasteland. PCA showed that organic C was the key factor to control bioavailability of zinc in the soils. The extreme, very high and medium zinc accumulation was found in 69% of studied soils. There is no ecological risk of zinc to living organisms in the study area, and in 90% of the soils there were no potentially negative effects of zinc to ecological receptors.

Adsorption and Desorption of Lead (Pb) in Sandy Soil Treated by Various Amendments

The ability of sandy soil to adsorb lead (Pb) to limit its dispersion in environmental compartments and its adverse effects on humans and ecological receptors depends on certain reaction parameters. The sandy soil has a low Pb retention capacity, but treatment of this soil with amendments such as bentonite, crabmeal and eggshells could significantly improve its ability to adsorb the Pb. To this end, various sorbent tests of Pb by sandy soils, soil amendments and soil+amendments have been carried out in a static mode in the laboratory. The adsorption parameters tested are: reaction time, volume/mass ratio, temperature, increasing Pb (II) concentrations, nature and type of amendment. Furthermore, it was under thermodynamic control and was endothermic in the case of an increase in adsorbed and exothermic Pb levels as they decreased. Moreover, the adsorption of Pb obeys the Langmuir model for the soil (R2=0.986), bentonite (R2=0.915) and crab meal (R2=0.790) and Freundlich for eggshells (R2=0.936). The adsorption of Pb as a function of the types and doses of amendment showed that the retention effect of Pb was very significant (p<0.0001) and that 2.5% of crab meal, compared to the minimum intakes of 10% bentonite and 20% eggshells were sufficient to adsorb the maximum Pb for soil treated with a single amendment. The application of two soil amendments showed that the amended soil adsorbed more Pb with the minimum Fe content compared to other amendments. These results show that crabmeal is an excellent biosolid for the retention of anthropogenic Pb. The desorption test demonstrates that Diethylene Triamine Pentacetic Acid (DTPA) extracted much higher amounts of freshly adsorbed Pb than those extracted with ammonium acetate. The amounts of Pb adsorbed were significantly correlated with the amounts of desorbed Pb. Adsorption and desorption are therefore important phenomena controlling the bioavailability of Pb in sandy soils.

Evaluating the zebrafish embryo toxicity test for pesticide hazard screening.

Given the numerous chemicals used in society, it is critical to develop tools for accurate and efficient evaluation of potential risks to human and ecological receptors. Fish embryo acute toxicity tests are 1 tool that has been shown to be highly predictive of standard, more resource-intensive, juvenile fish acute toxicity tests. However, there is also evidence that fish embryos are less sensitive than juvenile fish for certain types of chemicals, including neurotoxicants. The utility of fish embryos for pesticide hazard assessment was investigated by comparing published zebrafish embryo toxicity data from pesticides with median lethal concentration 50% (LC50) data for juveniles of 3 commonly tested fish species: rainbow trout, bluegill sunfish, and sheepshead minnow. A poor, albeit significant, relationship (r2 = 0.28; p < 0.05) was found between zebrafish embryo and juvenile fish toxicity when pesticides were considered as a single group, but a much better relationship (r2 = 0.64; p < 0.05) when pesticide mode of action was factored into an analysis of covariance. This discrepancy is partly explained by the large number of neurotoxic pesticides in the dataset, supporting previous findings that commonly used fish embryo toxicity test endpoints are particularly insensitive to neurotoxicants. These results indicate that it is still premature to replace juvenile fish toxicity tests with embryo-based tests such as the Organisation for Economic Co-operation and Development Fish Embryo Acute Toxicity Test for routine pesticide hazard assessment, although embryo testing could be used with other screening tools for testing prioritization. Environ Toxicol Chem 2017;36:1221-1226. © 2016 SETAC.

Separation of Bacteria, Protozoa and Carbon Nanotubes by Density Gradient Centrifugation.

Sustainable production and use of carbon nanotube (CNT)-enabled materials require efficient assessment of CNT environmental hazards, including the potential for CNT bioaccumulation and biomagnification in environmental receptors. Microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of CNTs. Quantification of CNT association with microbial cells requires efficient separation of CNT-associated cells from individually dispersed CNTs and CNT agglomerates. Here, we designed, optimized, and demonstrated procedures for separating bacteria (Pseudomonas aeruginosa) from unbound multiwall carbon nanotubes (MWCNTs) and MWCNT agglomerates using sucrose density gradient centrifugation. We demonstrate separation of protozoa (Tetrahymena thermophila) from MWCNTs, bacterial agglomerates, and protozoan fecal pellets by centrifugation in an iodixanol solution. The presence of MWCNTs in the density gradients after centrifugation was determined by quantification of 14C-labeled MWCNTs; the recovery of microbes from the density gradient media was confirmed by optical microscopy. Protozoan intracellular contents of MWCNTs and of bacteria were also unaffected by the designed separation process. The optimized methods contribute to improved efficiency and accuracy in quantifying MWCNT association with bacteria and MWCNT accumulation in protozoan cells, thus supporting improved assessment of CNT bioaccumulation.

Colloidal properties and stability of aqueous suspensions of few-layer graphene: Importance of graphene concentration

Understanding the colloidal stability of graphene is essential for predicting its transport and ecological risks in aquatic environments. We investigated the agglomeration of 14C-labeled few-layer graphene (FLG) at concentrations spanning nearly four orders of magnitude (2 μg/L to 10 mg/L) using dynamic light scattering and sedimentation measurements. FLG agglomerates formed rapidly in deionized water at concentrations >3 mg/L. From 1 mg/L to 3 mg/L, salt-induced agglomeration was decreased with dilution of FLG suspensions; the critical coagulation concentration of the more concentrated suspension (3 mg/L) was significantly lower than the dilute suspension (1 mg/L) in the presence of NaCl (1.6 mmol/L and 10 mmol/L, respectively). In contrast, FLG underwent slow agglomeration and settling at concentrations ≤0.1 mg/L in NaCl solutions and ambient waters with low ionic strength (<10 mmol/L). FLG nanoparticles with smaller lateral sizes (25 nm–75 nm) were shown to agglomerate more slowly than larger FLG, and these small FLG particles exhibited greater bioaccumulation in zebrafish embryo and stronger chorion penetration ability than larger FLG particles. These findings suggest that FLG at more environmentally relevant concentration is relatively stable and may have implications for exposure of small FLG to ecological receptors.

Predicting plant uptake of cadmium: validated with long-term contaminated soils.

Cadmium accumulates in plant tissues at low soil loadings and is a concern for human health. Yet at higher levels it is also of concern for ecological receptors. We determined Cd partitioning constants for 41 soils to examine the role of soil properties controlling Cd partitioning and plant uptake. From a series of sorption and dose response studies, transfer functions were developed for predicting Cd uptake in Cucumis sativa L. (cucumber). The parameter log Kf was predicted with soil pHca, logCEC and log OC. Transfer of soil pore-water Cd2+ to shoots was described with a power function (R 2 = 0.73). The dataset was validated with 13 long-term contaminated soils (plus 2 control soils) ranging in Cd concentration from 0.2 to 300 mg kg-1. The series of equations predicting Cdshoot from pore-water Cd2+ were able to predict the measured data in the independent dataset (root mean square error = 2.2). The good relationship indicated that Cd uptake to cucumber shoots could be predicted with Cdpore and Cd2+ without other pore-water parameters such as pH or Ca2+. The approach may be adapted to a range of plant species.

Biogeochemical controls on methylmercury in soils and sediments: Implications for site management.

Management of Hg-contaminated sites poses particular challenges because methylmercury (MeHg), a potent bio-accumulative neurotoxin, is formed in the environment, and concentrations are not generally predictable based solely on total Hg (THg) concentrations. In this review, we examine the state of knowledge regarding the chemical, biological, and physical controls on MeHg production and identify those most critical for contaminated site assessment and management. We provide a list of parameters to assess Hg-contaminated soils and sediments with regard to their potential to be a source of MeHg to biota and therefore a risk to humans and ecological receptors. Because some measurable geochemical parameters (e.g., DOC) can have opposing effects on Hg methylation, we recommend focusing first on factors that describe the potential for Hg bio-accumulation: site characteristics, Hg and MeHg concentrations, Hg availability, and microbial activity, where practical. At some sites, more detailed assessment of biogeochemistry may be required to develop a conceptual site model for remedial decision making. Integr Environ Assess Manag 2017;13:249-263. © 2016 SETAC.

Functional remediation components: A conceptual method of evaluating the effects of remediation on risks to ecological receptors

ABSTRACTGovernmental agencies, regulators, health professionals, tribal leaders, and the public are faced with understanding and evaluating the effects of cleanup activities on species, populations, and ecosystems. While engineers and managers understand the processes involved in different remediation types such as capping, pump and treat, and natural attenuation, there is often a disconnect between (1) how ecologists view the influence of different types of remediation, (2) how the public perceives them, and (3) how engineers understand them. The overall goal of the present investigation was to define the components of remediation types (= functional remediation). Objectives were to (1) define and describe functional components of remediation, regardless of the remediation type, (2) provide examples of each functional remediation component, and (3) explore potential effects of functional remediation components in the post-cleanup phase that may involve continued monitoring and assessment. Functional remediation components include types, numbers, and intensity of people, trucks, heavy equipment, pipes, and drill holes, among others. Several components may be involved in each remediation type, and each results in ecological effects, ranging from trampling of plants, to spreading invasive species, to disturbing rare species, and to creating fragmented habitats. In some cases remediation may exert a greater effect on ecological receptors than leaving the limited contamination in place. A goal of this conceptualization is to break down functional components of remediation such that managers, regulators, and the public might assess the effects of timing, extent, and duration of different remediation options on ecological systems.

Ecotoxicological assessment of biosolids by microcosms

Biosolids have been applied as soil amendments to improve and maintain the soil fertility and faster plant growth. In spite of its beneficial use, the potential risks of land disposal should be analyzed, considering potential ecological receptors in soil and water. This work describes the use of an early warning laboratory microcosm system to evaluate the integrated ecotoxicological potential of two biosolids: BIO-1 and BIO-2 (18 and 28 months after landfarming, respectively), from an effluent treatment station in a petrochemical and industrial district. The endpoints related to habitat function were: a) germination, growth and biomass of Phaseolus vulgaris; b) survival, biomass and number of cocoons of Eisenia andrei (Oligochaeta) and; c) reproduction of Folsomia candida (Collembola). The retention function was evaluated by testing the leachates using the tropical cladoceran Latonopsis australis (Cladocera) in a 48-h acute toxicity test, and growth of the aquatic plant Lemna minor in a 7-d chronic test. Tropical artificial soil (TAS) and a natural soil (NS) from the region were used as control soils. Results showed no chronic toxicity of BIO-1 and BIO-2 to the soil organisms tested, but acute toxicity of BIO-1 in the leachate for 50% of L. australis, and chronic toxicity of both biosolid leachates to L. minor (inhibition of growth rate), indicating potential risks to aquatic ecosystems. The results confirmed the ability of this microcosm system as a rapid tool to assess biosolid toxicity over time and its potential for hazardous waste characterization in environmental risk assessment, in a screening phase.

Risk Assessment of Metal Contamination in Soil and Groundwater in Asia: A Review of Recent Trends as well as Existing Environmental Laws and Regulations

Asia is experiencing a more rapid economic growth compared to any other regions. The contamination of soil and groundwater with metals can mainly be attributed to human activities; therefore, risk assessments to characterize the nature and magnitude of risks to humans and ecological receptors from contaminants are important. Risk assessments are often iterative processes, which involve identification and filling data gap. Experimental samplings, geostatistical and multivariate statistical methods as well as multimedia risk assessment modeling are the three major methodologies used in the assessment of metal contamination in soil and groundwater. This review highlights a number of measurements for improving risk calculation methods and expounds scientific approaches that involve the identification of the major source of contamination, exposure pathways and bioavailability of metals. In general, risk assessments of metals in soil and groundwater worldwide are mainly focused on the levels of contamination, identification of exposure pathways, and prediction of the probability of contamination. To date, very limited studies have reported the development of relevant environmental laws and policies in the regulation of soil and groundwater contamination in Asia. The development, variations and limitations in the regulations of soil and groundwater contamination among developed countries may provide helpful guidance for the developing countries in Asia.

Advancing Exposure Science through Chemical Data Curation and Integration in the Comparative Toxicogenomics Database.

Background:Exposure science studies the interactions and outcomes between environmental stressors and human or ecological receptors. To augment its role in understanding human health and the exposome, we aimed to centralize and integrate exposure science data into the broader biological framework of the Comparative Toxicogenomics Database (CTD), a public resource that promotes understanding of environmental chemicals and their effects on human health.Objectives:We integrated exposure data within the CTD to provide a centralized, freely available resource that facilitates identification of connections between real-world exposures, chemicals, genes/proteins, diseases, biological processes, and molecular pathways.Methods:We developed a manual curation paradigm that captures exposure data from the scientific literature using controlled vocabularies and free text within the context of four primary exposure concepts: stressor, receptor, exposure event, and exposure outcome. Using data from the Agricultural Health Study, we have illustrated the benefits of both centralization and integration of exposure information with CTD core data.Results:We have described our curation process, demonstrated how exposure data can be accessed and analyzed in the CTD, and shown how this integration provides a broad biological context for exposure data to promote mechanistic understanding of environmental influences on human health.Conclusions:Curation and integration of exposure data within the CTD provides researchers with new opportunities to correlate exposures with human health outcomes, to identify underlying potential molecular mechanisms, and to improve understanding about the exposome.Citation:Grondin CJ, Davis AP, Wiegers TC, King BL, Wiegers JA, Reif DM, Hoppin JA, Mattingly CJ. 2016. Advancing exposure science through chemical data curation and integration in the Comparative Toxicogenomics Database. Environ Health Perspect 124:1592–1599; http://dx.doi.org/10.1289/EHP174