An alternative approach to risk rank chemicals on the threat they pose to the aquatic environment

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The present study reviewed the impacts of wastewater on macroinvertebrates over 4 decades in a United Kingdom lowland river. This involved examining changes in chemicals, temperature, flow, and macroinvertebrate diversity from the 1970s until 2017 for a wastewater‐dominated river downstream of Swindon in the United Kingdom (population ~ 220 000). When the wastewater treatment process changed from trickling filter to activated sludge in 1991, biological oxygen demand was nearly halved (90th percentile from 8.1 to 4.6 mg/L), ammonia peaks dropped more than 7‐fold (90th percentile from 3.9 to 0.53 mg/L), whereas dissolved oxygen climbed consistently above 60% saturation (10th percentile from 49 to 64%) at a sampling point 2 km downstream of the wastewater treatment plant. A sustained increase in the number of macroinvertebrate species was evident from that point. River flow did not change, temperature rose slightly, and the major metal concentrations declined steadily over most of the monitoring period. Neither the introduction of phosphate stripping in 1999 nor the use of tertiary granular activated charcoal from 2008 to 2014 had strong positive effects on subsequent macroinvertebrate diversity. That the diversity still had not reached the ideal status by 2016 may be related to the modest habitat quality, agricultural pesticides, and limited recolonization potential in the catchment. The results indicate that urban wastewaters, with their chemical pollutants, are today probably not the biggest threat to the macroinvertebrate diversity of multiply stressed lowland rivers in the United Kingdom. Environ Toxicol Chem 2019;38:1820–1832. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC

Section: Discussionmentioning

confidence: 99%

What Works? the Influence of Changing Wastewater Treatment Type, Including Tertiary Granular Activated Charcoal, on Downstream Macroinvertebrate Biodiversity Over Time

Johnson

Jürgens²,

Edwards³

et al. 2019

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“…In general, it can be stated that the prioritization options are many, that prioritization outcomes are dynamic in space and time, and, hence, that the problem definition phase should be used to define precisely which ranking information is most valuable for selecting an abatement option. Regulatory prioritization used to prospectively steer preventive policies can thus be different from more realized environmental quality-based rankings (Johnson et al 2017).…”

Section: Prioritizationmentioning

confidence: 99%

Prospective mixture risk assessment and management prioritizations for river catchments with diverse land uses

Posthuma

Brown

Zwart³

et al. 2018

Ecological risk assessment increasingly focuses on risks from chemical mixtures and multiple stressors because ecosystems are commonly exposed to a plethora of contaminants and nonchemical stressors. To simplify the task of assessing potential mixture effects, we explored 3 land use–related chemical emission scenarios. We applied a tiered methodology to judge the implications of the emissions of chemicals from agricultural practices, domestic discharges, and urban runoff in a quantitative model. The results showed land use–dependent mixture exposures, clearly discriminating downstream effects of land uses, with unique chemical “signatures” regarding composition, concentration, and temporal patterns. Associated risks were characterized in relation to the land‐use scenarios. Comparisons to measured environmental concentrations and predicted impacts showed relatively good similarity. The results suggest that the land uses imply exceedances of regulatory protective environmental quality standards, varying over time in relation to rain events and associated flow and dilution variation. Higher‐tier analyses using ecotoxicological effect criteria confirmed that species assemblages may be affected by exposures exceeding no‐effect levels and that mixture exposure could be associated with predicted species loss under certain situations. The model outcomes can inform various types of prioritization to support risk management, including a ranking across land uses as a whole, a ranking on characteristics of exposure times and frequencies, and various rankings of the relative role of individual chemicals. Though all results are based on in silico assessments, the prospective land use–based approach applied in the present study yields useful insights for simplifying and assessing potential ecological risks of chemical mixtures and can therefore be useful for catchment‐management decisions. Environ Toxicol Chem 2018;37:715–728. © 2017 The Authors. Environmental Toxicology Chemistry Published by Wiley Periodicals, Inc.

“…China has also considered a "black list" of high PBT chemicals, being the ones deserving the most attention (Jin et al 2014). To avoid these potential errors, a different risk-ranking method has been proposed where a median or percentile of the ecotoxicity data set is compared against the median or a percentile of the MEC, and this has been recently applied to a range of chemicals in the United Kingdom (Donnachie et al 2014(Donnachie et al , 2016Johnson et al 2017) and in China . Typically, this is linked to the toxicity of the chemical and is based on a predicted-no-effect concentration (PNEC).…”

Section: Introductionmentioning

confidence: 99%

“…Together, both could distort the risk assessment by overlooking the chemical causing the most frequent damage to wildlife. To avoid these potential errors, a different risk-ranking method has been proposed where a median or percentile of the ecotoxicity data set is compared against the median or a percentile of the MEC, and this has been recently applied to a range of chemicals in the United Kingdom (Donnachie et al 2014(Donnachie et al , 2016Johnson et al 2017) and in China . Thus, the ecotoxicity value used in the present study is bounded firmly within the data set and is not a prediction beyond what has been recorded in ecotoxicity testing such as is used to generate a PNEC.…”

Section: Introductionmentioning

confidence: 99%

Which commonly monitored chemical contaminant in the Bohai region and the Yangtze and Pearl Rivers of China poses the greatest threat to aquatic wildlife?

Johnson

Jürgens

et al. 2018

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The present study assessed the relative risk of 29 chemical contaminants to aquatic wildlife in the Bohai region and the Yangtze and Pearl Rivers of China. River monitoring data from 2010 to 2015 for metals, pesticides, plasticizers, surfactants, polyaromatic hydrocarbons, flame retardants, and ammonia were collected. For each chemical, ecotoxicity data were compiled for Chinese-relevant aquatic species. The chemicals were ranked by relative risk either by comparing the ratios of the median river concentration divided by the median ecotoxicity concentration or by the percentage of river measurements which exceeded the lower 10th percentile ecotoxicity value. To provide context, these results were compared with the same analysis for rivers in the United Kingdom. From this collection of chemicals in Chinese rivers, the highest risks appear to be from Cu, closely followed by Zn, Fe, and Ni together with linear alkyl benzene sulfonate, nonylphenol, and NH . This risk, particularly from the metals, can be several times higher than that experienced in UK rivers when using the same analysis. Ammonia median concentrations were notably higher in the Pearl and Yangtze than in UK rivers. The results suggest that China should focus on controlling metal contamination to protect its aquatic wildlife. Environ Toxicol Chem 2018;37:1115-1121. © 2017 SETAC.