Development of a bioavailability-based risk assessment framework for nickel in Southeast Asia and Melanesia.

Nickel laterite ore deposits are becoming increasingly important sources of Ni for the global marketplace and are found mainly in tropical and subtropical regions, including Indonesia, the Philippines, Papua New Guinea, Cuba, and New Caledonia. There are few legislatively derived standards or guidelines for the protection of aquatic life for Ni in many of these tropical regions, and bioavailability-based environmental risk assessment (ERA) approaches for metals have mainly been developed and tested in temperate regions, such as the United States and Europe. This paper reports on a multi-institutional, 5-y testing program to evaluate Ni exposure, effects, and risk characterization in the Southeast Asia and Melanesia (SEAM) region, which includes New Caledonia, Papua New Guinea, the Philippines, and Indonesia. Further, we have developed an approach to determine if the individual components of classical ERA, including effects assessments, exposure assessments, and risk characterization methodologies (which include bioavailability normalization), are applicable in this region. A main conclusion of this research program is that although ecosystems and exposures may be different in tropical systems, ERA paradigms are constant. A large chronic ecotoxicity data set for Ni is now available for tropical species, and the data developed suggest that tropical ecosystems are not uniquely sensitive to Ni exposure; hence, scientific support exists for combining tropical and temperate data sets to develop tropical environmental quality standards (EQSs). The generic tropical database and tropical exposure scenarios generated can be used as a starting point to examine the unique biotic and abiotic characteristics of specific tropical ecosystems in the SEAM region. Integr Environ Assess Manag 2021;17:802-813. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Comparison of temperate and tropical freshwater species' acute sensitivities to chemicals: An update.

Toxicity data for tropical species are often lacking for deriving water quality guidelines (WQGs) and for conducting ecological risk assessment (ERA). To protect and safeguard valuable natural resources and important biodiversity in tropical freshwater ecosystems, a sound framework should be established to assess and manage the ecological risk of an ever-increasing number of chemicals that occur in the tropics. The present study aims to provide a more up-to-date comparison of the species sensitivity distributions (SSDs) between temperate and tropical freshwater species, by incorporating more acute toxicity data that have been documented. Results showed that temperate freshwater species are generally more sensitive to As, Cr, Pb, Hg, carbaryl, chlorpyrifos, DDT, lindane, and malathion than are their tropical counterparts, whereas tropical species tend to be more sensitive to un-ionized ammonia, Mn, chlordane, and phenol. No sensitivity differences were found between temperate and tropical freshwater species to Cu and pentachlorophenol. A general decline in sensitivity trend to chemicals was revealed by comparing taxon-specific SSDs, from crustaceans to mollusks, worms, fishes, and insects. On the basis of calculated 10% hazardous concentration (HC10) ratios from pairwise temperate and tropical SSDs, the temperate-to-tropic safe extrapolation factor was verified and refined as 5 for information. Integr Environ Assess Manag 2019;00:000-000. © 2019 SETAC.

Joining the dots between omics and environmental management.

With the rapid advancement of DNA sequencing technologies and the substantial reduction of their running costs, environmental genomics and transcriptomics become more affordable and popular in environmental toxicology. In parallel, there are also speedy improvements of mass spectrometry and nuclear magnetic resonance spectrometry, enabling high-throughput analyses of proteins and metabolites in biological samples and promoting research studies in proteomics and metabolomics. By applying these high-throughput omics technologies, researchers can quickly generate an unprecedentedly vast amount of biological data that may be useful to environmental management. However, the current pace of applying omics information in environmental management is still very slow, and lags well behind the rapid development of omics-based research. This timely commentary, therefore, calls for joint efforts to increase this pace and join the dots between omics and environmental management, turning omics into practical tools. Herein, I explore how omics can contribute to risk assessment and management of chemicals, and recommend what we can do to facilitate and promote the use of omics information in environmental management. This article is especially dedicated to my role model, mentor, and friend, Peter M Chapman (1951-2017), who sadly passed away on 26 September 2017. Integr Environ Assess Manag 2018;14:169-173. © 2017 SETAC.

Impacts of human activities on distribution of sulfate-reducing prokaryotes and antibiotic resistance genes in marine coastal sediments of Hong Kong.

Sulfate-reducing prokaryotes (SRPs) and antibiotic resistance genes (ARGs) in sediments could be biomarkers for evaluating the environmental impacts of human activities, although factors governing their distribution are not clear yet. By using metagenomic approach, this study investigated the distributions of SRPs and ARGs in marine sediments collected from 12 different coastal locations of Hong Kong, which exhibited different pollution levels and were classified into two groups based on sediment parameters. Our results showed that relative abundances of major SRP genera to total prokaryotes were consistently lower in the more seriously polluted sediments (P-value < 0.05 in 13 of 20 genera), indicating that the relative abundance of SRPs is a negatively correlated biomarker for evaluating human impacts. Moreover, a unimodel distribution pattern for SRPs along with the pollution gradient was observed. Although total ARGs were enriched in sediments from the polluted sites, distribution of single major ARG types could be explained neither by individual sediment parameters nor by corresponding concentration of antibiotics. It supports the hypothesis that the persistence of ARGs in sediments may not need the selection of antibiotics. In summary, our study provided important hints of the niche differentiation of SRPs and behavior of ARGs in marine coastal sediment.