Toward a network perspective in coastal ecosystem management.

Environmental management in coastal ecosystems has been challenged by the complex cumulative effects that occur when many small issues result in large ecological shifts. Current environmental management of these spaces focuses on identifying and limiting problematic stressors via a series of assessment techniques. Whilst there is a strong desire among managers to consider complexity in ecological responses to cumulative effects, current approaches for assessing risk focus on breaking down the issues into multiple cause and effect relationships. However, uncertainty arises when data and information for a place are limited, as is commonly the case, and this creates decision paralysis while more information is generated. Here, we discuss how ecological understanding of network interactions in coastal marine ecosystems can be used as a lens to bring together multiple lines of evidence and create actions. We list and describe four characteristics of marine ecosystem interaction networks including the possibility for; 1) indirect effects, 2) effects that emerge as stressor magnitude increases the number of network components implicated, 3) network interactions that amplify these indirect effects, and 4) feedbacks that reinforce or stabilise against indirect effects. We then link these four characteristics to three case studies of common coastal environmental issues to demonstrate how a general understanding of ecological interaction networks can enhance priorities for stressor management that can be applied even when specific data is limited.

The application of sediment quality guidelines and toxicity assessment to identify contaminant hotspots in an urbanised West Australian estuary.

This paper presents a tiered assessment approach that enabled identification, triage, interrogation and confirmation of significantly contaminated areas of an urbanised West Australian estuary. The spatial distribution of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and bioavailable metals was determined in surficial sediments of the Swan-Canning Estuary through broad-scale screening (500 cores, 100 composite samples, 20 locations). The application of sediment quality guideline values (SQGVs) enabled ranking of locations through risk-based scoring and identification of contaminant hotspots. Subsequent targeted ecotoxicological and chemical assessment was undertaken at the highest scoring location in each tributary (80 cores, 16 composite samples, 3 locations, 16 sites). In the Canning tributary, Bull Creek sediments demonstrated the highest metal concentrations and greatest number of SQGVs exceeded. High-level toxicity was experienced in copepods and moderate toxicity in mussels (test sensitivity: copepod>mussel>amphipod). Toxicity-inducing contamination was attributable to two stormwater outfalls and limited to 300 m from points of discharge. In the Swan tributary, Claisebrook sediments demonstrated the highest concentrations of all PAHs, most OCPs and metals and the greatest number of SQGVs exceeded. High-level toxicity was reported in fish and mussels and moderate toxicity in copepods and amphipods (test sensitivity: fish>mussel>amphipod>copepod). Toxicity-inducing contamination included a stretch of estuary >1 km long, and two stormwater outfalls in the area were likely sources. The distribution and nature of PAH contamination suggested an additional source at Claisebrook. This combined chemistry and biological effects dataset provides critical information for the management of planned major development and concomitant estuary-bed disturbance in the coming decade.

Triad-based screening risk assessment of the agricultural area exposed to the long-term PAHs contamination.

The aim of the study was ecological risk assessment (ERA) of the agricultural soils located in the vicinity of the highly industrialized area and exposed to different emission sources of polycyclic aromatic hydrocarbons (PAHs). In this study, we demonstrated the combination of generic and site-specific ERA approach for screening assessment and delineation of the area of a high ecological risk. Generic approach was based on a hazard quotient and indicated that 62% of the research area needs further assessment. For site-specific evaluation, the Triad approach was utilized. Information from three lines of evidence (LoE): chemical, ecotoxicological and ecological, was integrated into one environmental risk (EnvRI) index. The chemical risk was derived from toxic pressure coefficients based on the total PAHs concentration. The ecotoxicological LoE included an acute toxicity testing: the luminescent bacteria Aliivibrio fischeri activity in both liquid- and solid-phase samples and the ability of crustacean Thamnocephalus platyurus to food uptake. The ecological LoE comprised microbial parameters related to soil respiration and enzymatic activity. Integrated EnvRI index ranged from 0.44 to 0.94 and was mainly influenced by high values of chemical LoE risk, while the ecotoxicological and ecological LoE indicated no or low risk. Due to the relatively high uncertainty associated with the contradictory information given by LoEs, there is the need to confirm potential risk in a tier 2 analysis.

Nocturnal seston: A key to explain the cadmium transfer from seawater to mussels (Mytilus chilensis).

The objective of this work was to discover a biochemical pathway to explain the transfer of cadmium, a toxic element, from seawater to cultured mussels. Understanding the intricacies of this transfer is crucial for global mussel crops, as it has the potential to mitigate risks to human health and prevent economic losses in the industry. We focused our investigation on Yal Bay, a typical area with intense mussel aquaculture activity (16,000 t y-1) in the inland sea of southern Chile. Seasonal samples of blue mussels (Mytilus chilensis) were collected and analyzed from September 2014 to December 2015 at two integrated depths (0-5 m and 5-10 m). Diurnal and nocturnal seston, seawater, benthic sediments and decanted suspensions from the water column were recorded. Our findings indicate that nocturnal seston satisfactorily explains the presence of cadmium in Mytilus chilensis aquaculture throughout its annual temporal distribution (Spearman rs = 0.63, p = 0.002).

Microbiologically influenced corrosion-more than just microorganisms.

Microbiologically influenced corrosion (MIC) is a phenomenon of increasing concern that affects various materials and sectors of society. MIC describes the effects, often negative, that a material can experience due to the presence of microorganisms. Unfortunately, although several research groups and industrial actors worldwide have already addressed MIC, discussions are fragmented, while information sharing and willingness to reach out to other disciplines are limited. A truly interdisciplinary approach, which would be logical for this material/biology/chemistry-related challenge, is rarely taken. In this review, we highlight critical non-biological aspects of MIC that can sometimes be overlooked by microbiologists working on MIC but are highly relevant for an overall understanding of this phenomenon. Here, we identify gaps, methods, and approaches to help solve MIC-related challenges, with an emphasis on the MIC of metals. We also discuss the application of existing tools and approaches for managing MIC and propose ideas to promote an improved understanding of MIC. Furthermore, we highlight areas where the insights and expertise of microbiologists are needed to help progress this field.

Species delimitation and integrative taxonomy of the Reithrodontomys mexicanus (Rodentia: Cricetidae) cryptic complex.

Species boundaries are difficult to establish in groups with very similar morphology. As an alternative, it has been suggested to integrate multiple sources of data to clarify taxonomic problems in taxa where cryptic speciation processes have been reported. This is the case of the harvest mouse Reithrodontomys mexicanus, which has a problematic taxonomy history as it is considered a complex species. Here, we evaluate the cryptic diversity of R. mexicanus using an integrative taxonomy approach in order to detect candidate lineages at the species level. The molecular analysis used one mitochondrial (cytb) and two nuclear (Fgb-I7 and IRBP) genes. Species hypotheses were suggested based on three molecular delimitation methods (mPTP, bGMYC, and STACEY) and cytb genetic distance values. Skull and environmental space differences between the delimited species were also tested to complement the discrimination of candidate species. Based on the consensus across the delimitation methods and genetic distance values, four species were proposed, which were mostly supported by morphometric and ecological data: R. mexicanus clade I, R. mexicanus clade IIA, R. mexicanus clade IIIA, and R. mexicanus clade IIIB. In addition, the evolutionary relationships between the species that comprise the R. mexicanus group were discussed from a phylogenetic approach. Our findings present important taxonomic implications for Reithrodontomys, as the number of known species for this genus increases. Furthermore, we highlight the importance of the use of multiple sources of data in systematic studies to establish robust delimitations between species considered taxonomically complex.

Revisited a sediment quality triad approach in the Korean coastal waters: Past research, current status, and future directions.

We present a comprehensive review of the sediment quality triad (SQT) assessment studies in Korea. The bibliographic analysis was applied to evaluate how approaches in sediment assessment have evolved. A meta-analysis was performed, to evaluate potential risks of sedimentary persistent toxic substances (PTSs) reported in Korean coastal waters. Within the framework, we identified and discussed current status and spatiotemporal trends in contamination of both classic and emerging PTSs over the recent decadal period. Out of 26 target regions in Korea, five hotspots (Sihwa, Masan, Ulsan, Taean, and Gwangyang) of concern could be identified. Four of those regions have been designated as Specially-Managed Sea Area under the implementation of Total Pollution Load Management System in Korea, except for Taean coast (oil spill site). Meantime, we could identify three stepwise research phases based on a bibliographic analysis; Phase 1 (1995-2008), Phase 2 (2009-2015), and Phase 3 (2016-2020). It is noteworthy that a technical evolution of the SQT assessment by the phase was featured. It was also evidenced that in-depth studies adopting multiple lines of evidence (LOEs) became prevailed upon approaching Phase 3. In a quantitative manner, the toxicity explanatory power of target PTSs increased by about 10% in Phase 3 compared to the earlier phases. The meta-analysis using ratio-to-mean value method applied for the data set having all three LOEs indicated general improvement of sediment qualities in the hotspots. However, their associations quite varied across regions and years, reflecting a dynamicity in oceanographic settings and/or heterogeneity in toxicological effect or benthic community response. At present, SQT assessment adopting the increased LOEs generally supports better assessment. In conclusion, we suggest that future SQT studies globally should reaffirm the utility of the "multiple LOEs approach", focusing on the identification and management of causative toxicants that driving negative ecological impacts on marine ecosystems.

Application of a standard risk assessment scheme to a North Africa contaminated site (Sfax, Tunisia) -Tier 1.

Phosphorus is a critical element to agriculture, consequently global phosphate rock demand will remain rising to feed a growing world population. The beneficiation of phosphorous ore gives rise to several tons of a waste by-product [phosphogypsum (PG)] which valorisation is limited, within other reasons, by the risks posed to environment and human health. Although threatening, the accumulation in stacks is the only procedure so far practiced by several countries as a means to get rid of this industrial externality. As part of a NATO Science for Peace Project (SfP 983311) this study describes the application of an environmental risk assessment (ERA) framework, to assess the risks posed by a PG stack to the surrounding soils, in Sfax, Republic of Tunisia. The ERA followed a weight of evidence approach, supported by two lines of evidence (LoE): the chemical (ChemLoE) and the ecotoxicological (EcotoxLoE). Integrated risks point for risk values greater than 0.5 in soils collected in PG stack surrounding area. Soil salinization, has likely contributed to the exacerbation of risks, as well as to the lack of consistency between both LoEs. This study highlights the need of rethinking the weight given to each LoE in ERA, in areas where soil salinization is a reality.

Dataset for laboratory treatability experiment with activated carbon and bioamendments to enhance biodegradation of chlorinated ethenes.

This dataset describes the outcome of a laboratory trichloroethene (TCE) treatability experiment with liquid activated carbon and bioamendments. The treatability experiment included unamended microcosms, bioamended microcosms with a Dehalococcoides containing culture and electron donor, and bioamended microcosms including liquid activated carbon (PlumeStop®). Data were collected frequently over an 85-day experimental period. Data were collected for the following parameters: redox sensitive species, chlorinated ethenes, non-chlorinated end-products, electron donors, compound specific isotopes, specific bacteria and functional genes. The reductive dechlorination of TCE could be described by a carbon isotope enrichment factor (εC) of -7.1 ‰. In the amended systems, the degradation rates for the TCE degradation were 0.08-0.13 d-1 and 0.05-0.09 d-1 determined by concentrations and isotope fractionation, respectively. Dechlorination of cis-DCE was limited. This dataset assisted in identifying the impact of different bioamendments and activated carbon on biodegradation of chlorinated ethenes. The dataset is useful in optimising design and setup for future laboratory and field investigations. This study provides novel information on the effect of low dose liquid activated carbon on chlorinated ethenes degradation by applying isotopic and microbial techniques, and by linking the outcome to a field case study. The data presented in this article are related to the research article "Assessment of chlorinated ethenes degradation after field scale injection of activated carbon and bioamendments: Application of isotopic and microbial analyses" (Ottosen et al., 2021).

Assessment of chlorinated ethenes degradation after field scale injection of activated carbon and bioamendments: Application of isotopic and microbial analyses.

Over the last decade, activated carbon amendments have successfully been applied to retain chlorinated ethene subsurface contamination. The concept of this remediation technology is that activated carbon and bioamendments are injected into aquifer systems to enhance biodegradation. While the scientific basis of the technology is established, there is a need for methods to characterise and quantify the biodegradation at field scale. In this study, an integrated approach was applied to assess in situ biodegradation after the establishment of a cross sectional treatment zone in a TCE plume. The amendments were liquid activated carbon, hydrogen release donors and a Dehalococcoides containing culture. The integrated approach included spatial and temporal evaluations on flow and transport, redox conditions, contaminant concentrations, biomarker abundance and compound-specific stable isotopes. This is the first study applying isotopic and microbial techniques to assess field scale biodegradation enhanced by liquid activated carbon and bioamendments. The injection enhanced biodegradation from TCE to primarily cis-DCE. The Dehalococcoides abundances facilitated characterisation of critical zones with insufficient degradation and possible explanations. A conceptual model of isotopic data together with distribution and transport information improved process understanding; the degradation of TCE was insufficient to counteract the contaminant input by inflow into the treatment zone and desorption from the sediment. The integrated approach could be used to document and characterise the in situ degradation, and the isotopic and microbial data provided process understanding that could not have been gathered from conventional monitoring tools. However, quantification of degradation through isotope data was restricted for TCE due to isotope masking effects. The combination of various monitoring tools, applied frequently at high-resolution, with system understanding, was essential for the assessment of biodegradation in the complex, non-stationary system. Furthermore, the investigations revealed prospects for future research, which should focus on monitoring contaminant fate and microbial distribution on the sediment and the activated carbon.

Groundwater Quality of Aquifers Overlying the Oxnard Oil Field, Ventura County, California.

Groundwater samples collected from irrigation, monitoring, and municipal supply wells near the Oxnard Oil Field were analyzed for chemical and isotopic tracers to evaluate if thermogenic gas or water from hydrocarbon-bearing formations have mixed with surrounding groundwater. New and historical data show no evidence of water from hydrocarbon-bearing formations in groundwater overlying the field. However, thermogenic gas mixed with microbial methane was detected in 5 wells at concentrations ranging from 0.011-9.1 mg/L. The presence of these gases at concentrations <10 mg/L do not indicate degraded water quality posing a known health risk. Analysis of carbon isotopes (δ13C-CH4) and hydrogen isotopes (δ2H-CH4) of methane and ratios of methane to heavier hydrocarbon gases were used to differentiate sources of methane between a) microbial, b) thermogenic or c) mixed sources. Results indicate that microbial-sourced methane is widespread in the study area, and concentrations overlap with those from thermogenic sources. The highest concentrations of thermogenic gas were observed in proximity to relatively high density of oil wells, large injection volumes of water disposal and cyclic steam, shallow oil development, and hydrocarbon shows in sediments overlying the producing oil reservoirs. Depths of water wells containing thermogenic gas were within approximately 200 m of the top of the Vaca Tar Sand production zone (approximately 600 m below land surface). Due to the limited sampling density, the source and pathways of thermogenic gas detected in groundwater could not be conclusively determined. Thermogenic gas detected in the absence of co-occurring water from hydrocarbon-bearing formations may result from natural gas migration over geologic time from the Vaca Tar Sand or deeper formations, hydrocarbon shows in sediments overlying producing zones, and/or gas leaking from oil-field infrastructure. Denser sampling of groundwater, potential end-members, and pressure monitoring could help better distinguish pathways of thermogenic gases.

Elevated Magnesium Concentrations Altered Freshwater Assemblage Structures in a Mesocosm Experiment.

Magnesium (Mg) is a mining-related contaminant in the Alligators Rivers Region of tropical northern Australia. A mesocosm experiment was used to assess Mg toxicity to aquatic freshwater assemblages. Twenty-five 2700-L tubs were arranged, stratified randomly, on the bed of Magela Creek, a seasonally flowing, sandy stream channel in the Alligator Rivers Region of northern Australia. The experiment comprised 5 replicates of 4 nominal Mg treatments, 2.5, 7.5, 23, and 68 mg L-1 , and a control. Phytoplankton biomass, and diatom, zooplankton, and macroinvertebrate assemblages present in the treatment tubs were sampled before and after Mg addition. A significant negative relationship between phytoplankton biomass and Mg was observed 4 wk after Mg addition as measured by chlorophyll a concentrations (r2 = 0.97, p = 0.01). This result was supported by reductions in some major phytoplankton groups in response to increasing Mg concentrations, in the same experiment and from independent field studies. There was a significant negative relationship between zooplankton assemblage similarity (to control) and Mg concentrations (r2 = 0.96, p = 0.002). Seven weeks after Mg addition, macroinvertebrate assemblages were dominated by 3 microcrustacean groups (Ostracoda, Cladocera, and Copepoda), each reaching maximum abundance at intermediate Mg concentrations (i.e., unimodal responses). The responses of phytoplankton and zooplankton were used to derive assemblage effect concentrations (Mg concentrations resulting in x% of the assemblage change [ECx]). Magnesium concentrations resulting in assemblage EC01 values were <3 mg L-1 . Together with candidate guideline values from other laboratory- and field-based lines of evidence, the mesocosm EC01 values were incorporated into a weight-of-evidence framework for a robust regulatory approach to environmental protection. Environ Toxicol Chem 2020;39:1973-1987. © 2020 Commonwealth of Australia. Published by Wiley Periodicals LLC on behalf of SETAC.

Natural attenuation of a chlorinated ethene plume discharging to a stream: Integrated assessment of hydrogeological, chemical and microbial interactions.

Attenuation processes of chlorinated ethenes in complex near-stream systems result in site-specific outcomes of great importance for risk assessment of contaminated sites. Additional interdisciplinary and comprehensive field research is required to enhance process understanding in these systems. In this study, several methods were combined in a multi-scale interdisciplinary in-situ approach to assess and quantify the near-stream attenuation of a chlorinated ethene plume, mainly consisting of cis-dichloroethene (cis-DCE) and vinyl chloride (VC), discharging to a lowland stream (Grindsted stream, Denmark) over a monitoring period of seven years. The approach included: hydrogeological characterisation, reach scale contaminant mass balance analysis, quantification of contaminant mass discharge, streambed fluxes of chlorinated ethenes quantified using Sediment Bed Passive Flux Meters (SBPFMs), assessment of redox conditions, temporal assessment of contaminant concentrations, microbial analysis, and compound-specific isotope analysis (CSIA). This study site exhibits a special attenuation behaviour not commonly encountered in field studies: the conversion from an initially limited degradation case (2012-16), despite seemingly optimal conditions, to one presenting notable levels of degradation (2019). Hence, this study site provides a new piece to the puzzle, as sites with different attenuation behaviours are required in order to acquire the full picture of the role groundwater-surface water interfaces have in risk mitigation. In spite of the increased degradation in the near-stream plume core, the contaminant attenuation was still incomplete in the discharging plume. A conceptualization of flow, transport and processes clarified that hydrogeology was the main control on the natural attenuation, as short residence times of 0.5-37 days restricted the time in which dechlorination could occur. This study reveals the importance of: taking an integrated approach to understand the influence of all attenuation processes in groundwater - surface water interactions; considering the scale and domain of interest when determining the main processes; and monitoring sufficiently both spatially and temporally to cover the transient conditions.

Chlorinated ethene plume evolution after source thermal remediation: Determination of degradation rates and mechanisms.

The extent, mechanism(s), and rate of chlorinated ethene degradation in a large tetrachloroethene (PCE) plume were investigated in an extensive sampling campaign. Multiple lines of evidence for this degradation were explored, including compound-specific isotope analysis (CSIA), dual C-Cl isotope analysis, and quantitative real-time polymerase chain reaction (qPCR) analysis targeting the genera Dehalococcoides and Dehalogenimonas and the genes vcrA, bvcA, and cerA. A decade prior to this sampling campaign, the plume source was thermally remediated by steam injection. This released dissolved organic carbon (DOC) that stimulated microbial activity and created reduced conditions within the plume. Based on an inclusive analysis of minor and major sampling campaigns since the initial site characterization, it was estimated that reduced conditions peaked 4 years after the remediation event. At the time of this study, 11 years after the remediation event, the redox conditions in the aquifer are returning to their original state. However, the DOC released from the remediated source zone matches levels measured 3 years prior and plume conditions are still suitable for biotic reductive dechlorination. Dehalococcoides spp., Dehalogenimonas spp., and vcrA, bvcA, and cerA reductive dehalogenase genes were detected close to the source, and suggest that complete, biotic PCE degradation occurs here. Further downgradient, qPCR analysis and enriched δ13C values for cis-dichloroethene (cDCE) suggest that cDCE is biodegraded in a sulfate-reducing zone in the plume. In the most downgradient portion of the plume, lower levels of specific degraders supported by dual C-Cl analysis indicate that the biodegradation occurs in combination with abiotic degradation. Additionally, 16S rRNA gene amplicon sequencing shows that organizational taxonomic units known to contain organohalide-respiring bacteria are relatively abundant throughout the plume. Hydraulic conductivity testing was also conducted, and local degradation rates for PCE and cDCE were determined at various locations throughout the plume. PCE degradation rates from sampling campaigns after the thermal remediation event range from 0.11 to 0.35 yr-1. PCE and cDCE degradation rates from the second to the third sampling campaigns ranged from 0.08 to 0.10 yr-1 and 0.01 to 0.07 yr-1, respectively. This is consistent with cDCE as the dominant daughter product in the majority of the plume and cDCE degradation as the time-limiting step. The extensive temporal and spatial analysis allowed for tracking the evolution of the plume and the lasting impact of the source remediation and illustrates that the multiple lines of evidence approach is essential to elucidate the primary degradation mechanisms in a plume of such size and complexity.

A multiple lines of evidence approach for identifying geologic heterogeneities in conceptual site models for performance assessments.

Model-based decision making is commonly used in performance assessments to assure water resource protection for both human health and the environment for hundreds of years into the future. To make decisions regarding aquifer protection against potential contamination, a conceptual site model (CSM) describing the hydrodynamic behavior needs to account for subsurface heterogeneities in sufficient detail. When site-specific data are sparse, larger-scale geologic descriptions are adopted with the consequence of losing small-scale features (at the cm scale) that can control contaminant transport. In this study, a multiple lines of evidence approach is used to construct vadose zone CSMs based on an evaluation of several types of data, including geologic logs, borehole moisture content and concentration data, geophysical spectral gamma logging data, and groundwater concentration data for a tank farm at the Hanford Site in southeastern Washington State. The resulting CSMs of the unsaturated zone represent a synthesis of what is known about flow and transport processes at the site-scale and maintain consistency with knowledge that has been accumulated at the regional scale. Through a process of extensive data analyses, a systematic approach is described to create an evidence base that supports the evaluation and development of CSMs. Numerical models are then used to evaluate the impact that smaller-scale heterogeneities have on contaminant transport through the vadose zone for a performance assessment on waste tank closure. Together, the field data and the numerical experiments suggest that although small-scale features close to source releases can have an impact on horizontal spreading, overall there is a relatively minor impact on transport for the site under study as evaluated by differences in peak fluxes and arrival times for historical leak events, and for potential releases resulting from waste tank closure. Use of alternative CSMs, developed through careful examination of available characterization and monitoring data, provides confidence that geologic heterogeneities do not impact contaminant transport behavior significantly enough to alter the assessment of risk for closure at this site.

Finding New Cell Wall Regulatory Genes in Populus trichocarpa Using Multiple Lines of Evidence.

Understanding the regulatory network controlling cell wall biosynthesis is of great interest in Populus trichocarpa, both because of its status as a model woody perennial and its importance for lignocellulosic products. We searched for genes with putatively unknown roles in regulating cell wall biosynthesis using an extended network-based Lines of Evidence (LOE) pipeline to combine multiple omics data sets in P. trichocarpa, including gene coexpression, gene comethylation, population level pairwise SNP correlations, and two distinct SNP-metabolite Genome Wide Association Study (GWAS) layers. By incorporating validation, ranking, and filtering approaches we produced a list of nine high priority gene candidates for involvement in the regulation of cell wall biosynthesis. We subsequently performed a detailed investigation of candidate gene GROWTH-REGULATING FACTOR 9 (PtGRF9). To investigate the role of PtGRF9 in regulating cell wall biosynthesis, we assessed the genome-wide connections of PtGRF9 and a paralog across data layers with functional enrichment analyses, predictive transcription factor binding site analysis, and an independent comparison to eQTN data. Our findings indicate that PtGRF9 likely affects the cell wall by directly repressing genes involved in cell wall biosynthesis, such as PtCCoAOMT and PtMYB.41, and indirectly by regulating homeobox genes. Furthermore, evidence suggests that PtGRF9 paralogs may act as transcriptional co-regulators that direct the global energy usage of the plant. Using our extended pipeline, we show multiple lines of evidence implicating the involvement of these genes in cell wall regulatory functions and demonstrate the value of this method for prioritizing candidate genes for experimental validation.

Evaluating freshwater mining sediment toxicity in Tasmania: Achieving strong multiple lines of evidence.

Mining-impacted aquatic systems could be at risk from an assortment of pollutants. The present study evaluated toxicity of mining site sediments from western Tasmania by conducting bioassays with two Australian freshwater species (Chironomus tepperi and Austrochiltonia subtenuis). The present study used multiple lines of evidence (LoE) to assess risk to aquatic biota and the potential sources of that risk at these sites using a sediment quality guideline (SQG) comparison approach (i.e. comparing chemical concentrations at the site (in this case metals, sulfate, and acidic pH) to sediment guideline values) as well as a statistical approach (principle component analysis). Five of the nine mining site sediments showed significant toxicity to both species using survival (A. subtenuis and C. tepperi) and emergence (C. tepperi) as endpoints. Each LoE (SQG comparison and PCA analysis) provided a list of possible contaminants of concern for toxic sites, each list differing from one another. Evaluating these LoE collectively resulted in a stronger characterization of causality and reduced the potential contaminants of concern to a select few, including mainly: copper, sulfate, and acidic pH. Although using multiple lines of evidence reduced the number of potential contaminants of concern, the causality results were still not entirely conclusive, thus we also conducted preliminary investigations using toxicity identification evaluations (TIEs). These TIE investigations, showed the overall importance of acidic pH in these sediments, but also show the need for further work to improve the TIE technique for these types of sediment. The present study illustrates the strengths of using multiple LoE in assessing aquatic risk, especially in the assessment of complex sediments such as those in mining areas of Tasmania. The study, perhaps more importantly, also provides the foundation for more focused work to be conducted in the future to better understanding the implications of mining in western Tasmania.

Guidance on the use of the weight of evidence approach in scientific assessments.

EFSA requested the Scientific Committee to develop a guidance document on the use of the weight of evidence approach in scientific assessments for use in all areas under EFSA's remit. The guidance document addresses the use of weight of evidence approaches in scientific assessments using both qualitative and quantitative approaches. Several case studies covering the various areas under EFSA's remit are annexed to the guidance document to illustrate the applicability of the proposed approach. Weight of evidence assessment is defined in this guidance as a process in which evidence is integrated to determine the relative support for possible answers to a question. This document considers the weight of evidence assessment as comprising three basic steps: (1) assembling the evidence into lines of evidence of similar type, (2) weighing the evidence, (3) integrating the evidence. The present document identifies reliability, relevance and consistency as three basic considerations for weighing evidence.

Scientific Opinion of the PPR Panel on the follow-up of the findings of the External Scientific Report 'Literature review of epidemiological studies linking exposure to pesticides and health effects'.

In 2013, EFSA published a comprehensive systematic review of epidemiological studies published from 2006 to 2012 investigating the association between pesticide exposure and many health outcomes. Despite the considerable amount of epidemiological information available, the quality of much of this evidence was rather low and many limitations likely affect the results so firm conclusions cannot be drawn. Studies that do not meet the 'recognised standards' mentioned in the Regulation (EU) No 1107/2009 are thus not suited for risk assessment. In this Scientific Opinion, the EFSA Panel on Plant Protection Products and their residues (PPR Panel) was requested to assess the methodological limitations of pesticide epidemiology studies and found that poor exposure characterisation primarily defined the major limitation. Frequent use of case-control studies as opposed to prospective studies was considered another limitation. Inadequate definition or deficiencies in health outcomes need to be avoided and reporting of findings could be improved in some cases. The PPR Panel proposed recommendations on how to improve the quality and reliability of pesticide epidemiology studies to overcome these limitations and to facilitate an appropriate use for risk assessment. The Panel recommended the conduct of systematic reviews and meta-analysis, where appropriate, of pesticide observational studies as useful methodology to understand the potential hazards of pesticides, exposure scenarios and methods for assessing exposure, exposure-response characterisation and risk characterisation. Finally, the PPR Panel proposed a methodological approach to integrate and weight multiple lines of evidence, including epidemiological data, for pesticide risk assessment. Biological plausibility can contribute to establishing causation.

Refining health risk assessment by incorporating site-specific background concentration and bioaccessibility data of Nickel in soil.

Risk assessment of Nickel (Ni) in a brownfield site contaminated was refined by incorporating the site-specific background level (SSBL) derived using multiple lines of evidence technology and bioaccessibility measured by the Unified Bioaccessibility Method (UBM) and Inhalation Bioaccessibility Method (IBM). The results revealed that the SSBL was 80mg/kg, which was much higher than the general soil screening value (GSSL) (50mg/kg) and more than two times regional background level reported for Tianjing (33mg/kg). The average bioaccessibility for the gastric and intestinal phases was 24.2% (8.6%-54.4%) and 12.6% (7.7%-17.1%), respectively. In simulated lung fluid, only 2.1% (1.0%-4.6%) of Ni in the soil particle was bioaccessible. The amount of samples exceeding the acceptable level was reduced by 50% when SSBL, other than GSSL, was used as the screening value. Moreover, the site-specific target level (SSTL) under acceptable risk level was increased from 94mg/kg to 283mg/kg when bioaccessibility was considered, and the amount of samples above SSTL was reduced to 10%. The study indicated that incorporating site-specific background levels and bioaccessibility data of contaminants in a given site has the potential to support health risk assessment decisions and can reduce the remediation cost greatly.