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Ecological risk assessment (ERA) has been widely applied in characterizing the risk of chemicals to organisms and ecosystems. The paucity of toxicity data on local biota living in the different compartments of an ecosystem and the absence of a suitable methodology for multi-compartment spatial risk assessment at the regional scale has held back this field. The major objective of this study was to develop a methodology to quantify and distinguish the spatial distribution of risk to ecosystems at a regional scale. A framework for regional multi-compartment probabilistic ecological risk assessment (RMPERA) was constructed and corroborated using a bioassay of a local species. The risks from cadmium (Cd) pollution in river water, river sediment, coastal water, coastal surface sediment and soil in northern Bohai Rim were examined. The results indicated that the local organisms in soil, river, coastal water, and coastal sediment were affected by Cd. The greatest impacts from Cd were identified in the Tianjin and Huludao areas. The overall multi-compartment risk was 31.4% in the region. The methodology provides a new approach for regional multi-compartment ecological risk assessment.

The goal of protecting the aquatic environment through testing thousands of chemicals against hundreds of aquatic species with thousands of endpoints while also considering mixtures is impossible given the present resources. Much of the impetus for studies on micropollutants, such as pharmaceuticals, came from the topic of endocrine disruption in wild fish. But despite concern over reductions in fish fertility, there is little evidence that fish populations are in peril. Indeed, fish biologists suggest that many cyprinid populations have been recovering for the past 30 to 40 yr. The central assumption, key to current risk assessment, that effects observed in the laboratory or predicted by models are readily transferrable to the population level, is therefore questionable. The neglect in monitoring wildlife populations is the key weakness in environmental protection strategies. If we do not know whether aquatic wildlife species are declining or increasing, how valuable are our other ecotoxicological activities?

Aquatic organisms can be exposed to thousands of chemicals discharged by the human population. Many of these chemicals are considered disruptive to aquatic wildlife; the literature on the impacts of these chemicals grows daily. However, since time and resources are not infinite, we must focus on the chemicals which represent the greatest threat. One group of chemicals of increasing concern is the pharmaceuticals, where the struggle is to identify which of them represent the greatest threat. In the present study, we compiled a list of 12 pharmaceuticals based on scoring the prevalence of different compounds from previous prioritization reviews. These included rankings based on prescription data, environmental concentrations, PEC/PNEC ratios, PBT, and fish plasma model approaches. The most frequently cited were diclofenac, paracetamol, ibuprofen, carbamazepine, naproxen, atenolol, ethinylestradiol, aspirin, fluoxetine, propranolol, metoprolol and sulfamethoxazole. For each pharmaceutical, literature on effect concentrations was compiled and compared with river concentrations in the UK. The pharmaceuticals were ranked on the degree of difference between the median effect and median river concentrations. EE2 was ranked as the highest concern, followed by fluoxetine, propranolol and paracetamol. The relative risk of these pharmaceuticals was compared with those of metals and some persistent organic pollutants. Pharmaceuticals appear to be less of a threat to aquatic organisms than some metals (Cu, Al, Zn) and triclosan using this ranking approach

A total of 81 roach (Rutilus rutilus) collected from 13 southern English river sites between 2007 and 2012, were analysed for organochlorine pesticides, PCBs, PBDEs and some metals. Unexpectedly high concentrations of the banned insecticide DDT and its degradation products DDE and DDD (∑DDTs) were found in the 10 fish from the river Lee (or Lea) which averaged 88±70 (standard deviation) µg/kg ww, almost 20 times higher than the average for the remaining sites (4.8±3.1 µg/kg). All fish from that site exceeded the Canadian Tissue Residue Guideline (environmental quality standard) of 14 µg/kg ∑DDTs. Concentrations of the insecticides chlordane and lindane as well as copper, which is often used as a fungicide, were also elevated in fish from the Lee, though not as much as those of DDTs. A likely explanation for these observations was found in a nearby former pesticide factory, which had stopped production about three decades earlier. An extensive review of recent literature data on DDT in wild European fish found that, while levels are now generally low, there were several other hotspots with ∑DDTs levels that may still be of concern.

Ecological risk assessment (ERA) has been widely applied in characterizing the risk of chemicals to organisms and ecosystems. The paucity of toxicity data on local biota living in the different compartments of an ecosystem and the absence of a suitable methodology for multi-compartment spatial risk assessment at the regional scale has held back this field. The major objective of this study was to develop a methodology to quantify and distinguish the spatial distribution of risk to ecosystems at a regional scale. A framework for regional multi-compartment probabilistic ecological risk assessment (RMPERA) was constructed and corroborated using a bioassay of a local species. The risks from cadmium (Cd) pollution in river water, river sediment, coastal water, coastal surface sediment and soil in northern Bohai Rim were examined. The results indicated that the local organisms in soil, river, coastal water, and coastal sediment were affected by Cd. The greatest impacts from Cd were identified in the Tianjin and Huludao areas. The overall multi-compartment risk was 31.4% in the region. The methodology provides a new approach for regional multi-compartment ecological risk assessment.

This study evaluated the potential concentrations of four antibiotics: ciprofloxacin (CIP), sulfamethoxazole (SUF), trimethoprim (TRI) and erythromycin (ERY) throughout the rivers of Europe. This involved reviewing national consumption rates together with assessing excretion and sewage treatment removal rates. From this information, it was possible to construct best, expected and worst case scenarios for the discharge of these antibiotics into rivers. Consumption data showed surprising variations, up to 200-fold in the popularity of different antibiotics across different European nations. Using the water resources model GWAVA which has a spatial resolution of approximately 6 × 9 km, river water concentrations throughout Europe were predicted based on 31-year climate data. The modelled antibiotic concentrations were within the range of measurements reported previously in European effluents and rivers. With the expected scenario, the predicted annual-average antibiotic concentrations ranged between 0 and 10 ng/L for 90% by length of surface waters. In the worst case scenario concentrations could reach between 0.1 and 1 μg/L at the most exposed locations. As both predicted and observed sewage effluent concentrations were below reported effect levels for the most sensitive aquatic wildlife, no direct toxicity in rivers is expected. Predicted river concentrations for CIP and ERY were closest to effect levels in wildlife, followed by SUF which was 2–3 orders of magnitude lower. TRI appeared to be of the least concern with around 6 orders of magnitude difference between predicted and effect levels. However, mixture toxicity may elevate this risk and antibiotic levels of 0.1–1 μg/L in hotspots may contribute to local environmental antibiotic resistance in microorganisms.

Around twenty progestins (also called gestagens, progestogens or progestagens) are used today in assisting a range of medical conditions from endometrial cancer to uterine bleeding and as an important component of oral contraception. These progestins can bind to a wide range of receptors including progestin, estrogen, androgen, glucocorticoid, mineralocorticoid receptor, as well as sex hormone and corticosteroid binding globulins. It appear that only five of these (four synthetic and one natural) progestins have so far been studied in sewage effluent and surface waters. Analysis has reported values as either non-detects or low ng/L in rivers. Seven of the progestins have been examined for their effects on aquatic vertebrates (fish and frogs). The greatest concern is associated with levonorgestrel, norethisterone and gestodene and their ability to reduce egg production in fish at levels of 0.8-1.0 ng/L. The lack of environmental measurements, and some of the contradictions in existing values, however, hampers our ability to make a risk assessment. Only a few of ng/L of ethynodiol diacetate and desogestrel in water would be needed for fish to receive a human therapeutic dose for these progestins according to modelled bioconcentration factors. But for the other synthetic progestins levels would need to reach tens or hundreds of ng/L to achieve a therapeutic dose. Nevertheless, the wide range of compounds, diverse receptor targets and the effect on fish reproduction at sub ng/L levels should prompt further research. The ability to impair female reproduction at very low concentrations make the progestins arguably the most important pharmaceutical group of concern after ethinylestradiol., SCOPUS: re.j, info:eu-repo/semantics/published

Measurements have shown low levels of PCBs in water but relatively high concentrations in the resident fish of the River Thames (UK). To better understand the distribution and behaviour of PCBs in the Thames river basin and their potential risks, a level III fugacity model was applied to selected PCB congeners (PCB 52, PCB 118 and PCB 153). The modelling results indicated that fish and sediments represent environmental compartments with the highest PCB concentrations; but the greatest mass of PCBs (over 70%) is likely to remain in the soil. As emissions decline, soil could then act as a significant secondary source of PCBs with the river bed-sediment functioning as a long-term reservoir of PCBs. The predicted changes in temperature and rainfall forecast in the UK Climate Projections 2009 (UKCP09) had only a modest influence on PCB fate in the model. The most significant result being a tendency for climate change to enhance the evaporation of PCBs from soil to air in Thames catchment.

Nano silver and nano zinc-oxide monthly concentrations in surface waters across Europe were modeled at ~6 × 9 km spatial resolution. Nano-particle loadings from households to rivers were simulated considering household connectivity to sewerage, sewage treatment efficiency, the spatial distribution of sewage treatment plants, and their associated populations. These loadings were used to model temporally varying nano-particle concentrations in rivers, lakes and wetlands by considering dilution, downstream transport, water evaporation, water abstraction, and nano-particle sedimentation. Temporal variability in concentrations caused by weather variation was simulated using monthly weather data for a representative 31-year period. Modeled concentrations represent current levels of nano-particle production. Two scenarios were modeled. In the most likely scenario, half the river stretches had long-term average concentrations exceeding 0.002 ng/L nano silver and 1.5 ng/L nano zinc oxide. In 10% of the river stretches, these concentrations exceeded 0.18 ng/L and 150 ng/L, respectively. Predicted concentrations were usually highest in July.

Thirty-five European eels (Anguilla anguilla), caught in 2007 in the river Thames upstream and downstream of both London and the tidal limit, were analysed for PCBs and organochlorine pesticides. Most chemicals were detectable in every fish, although they have been banned or severely restricted for many years. In general, the tidal eels were more contaminated than upstream ones, which was related to their higher lipid contents. The ICES7 indicator PCB concentrations ranged overall from 4.2 to 124 µg/kg fresh weight with averages of 33 and 56 µg/kg for the upstream and tidal eels; 3.5-104 µg/kg, average 26 and 48 µg/kg of that were ICES6 PCBs. Total DDT was on average 16 µg/kg (1.7-38 µg/kg) upstream and 18 µg/kg (8.6-35 µg/kg) downstream with about half of that provided by pp’DDE. Lindane (gamma-HCH) was found at up to 2.8 µg/kg (averages 0.58 and 1.1 µg/kg upstream and downstream) and hexachlorobenzene (HCB) was on average 1.9 and 2.5 µg/kg in the two groups with a maximum of 6.4 µg/kg in each. Therefore all individuals passed the European Environmental Quality Standard (EQS) of 10 µg/Kg for HCB. PCB contamination was fairly typical for recent UK eel data, whilst DDE and lindane concentrations were lower than most previous UK eel studies, perhaps reflecting a downward trend. Although not as highly contaminated as some eels from previous UK and European studies, the presence of so many of these chemicals, with their known health effects may represent a stress for the fish or higher predators, such as birds.

This study describes the occurrence, fate, and removal of free estrogens (estrone (E1), 17 beta-estradiol (E2), estriol (E3), 17 alpha-ethynylestradiol (EE2)) and their glucuronide and sulfate conjugates (estrone-3-sulphate (E1-3S), 17 beta-estradiol-3-sulfate (E2-3S), estriol-3-sulfate (E3-3S), estrone-3-glucuronide (E1-3G), 17 beta-estradiol-3-glucuronide (E2-3G), and estriol-3-glucuronide (E3-3G)) in 12 sewage treatment plants in Japan. Glucuronide conjugates were only rarely detected in sewage influents and entirely eliminated within the treatment plants. E1 was found at 69 ng/L, E2 at 108 ng/L, E1-3S at 18 ng/L, and E2-3S at 78 ng/L in the sewage influents. The average removal efficiency for E1, E2, and sulfate conjugates was 88, 92, and 93%, respectively, following activated sludge treatment. The removal of E1 and E2 was improved with increasing the sludge retention time (SRT), with the highest removal typically found from 12 days SRT onward. The removal of sulfate conjugates was also related to SRT with highest removals found from eight days SRT onward. No correlation was found between the hydraulic retention time and the removal of any of the estrogens. The ozone dosage of 4-7 mg/L reduced E3 and E2-3S and E3-3S to below detection levels. Overall ozonation reduced the estrogenicity of the effluents as expressed as estradiol equivalents from 8.4 to 0.7 ng/L. The results suggest adequate river basin management of estrogens in Japan could be accomplished by a mixture of activated sludge plants with long SRT and where necessary, the addition of tertiary ozonation.

Recent interest in the environmental fate and effects of manufactured CeO2 nanomaterials (nanoceria) has stemmed from its expanded use for a variety of applications including fuel additives, catalytic converters, chemical and mechanical planarization media and other uses. This has led to a wave of publications on the toxicological effects of nanoceria in ecological receptor species, but only limited information is available on possible environmental releases, concentrations in environmental media, or environmental transformations. In this paper, we make initial estimates of likely environmental releases and exposure concentrations in soils and water and compare them to published toxicity values. Insufficient information was available to estimate aquatic exposures, but we estimated inputs to a hypothetical wastewater treatment plant that could result in effluent concentrations that would result in acute toxicity to the most sensitive aquatic organisms tested so far, cyanobacteria. The purpose of this exercise is to identify which areas are lacking in data to perform either regional or site specific ecological risk assessments. While estimates can be made for releases from use as a diesel fuel additive, and predicted toxicity is low in most terrestrial species tested to date, estimates for releases from other uses are difficult at this stage. We recommend that future studies focus on environmentally realistic exposures that take into account potential environmental transformations of the nanoceria surface as well as chronic toxicity studies in benthic aquatic organisms, soil invertebrates and microorgansims.

The natural range of fish species in our rivers is related to flow, elevation, temperature, local habitat and connectivity. For over 2000 years humans have altered to varying degrees the river habitat. In the last 200 years we added to the environmental disruption by discharging poorly treated sewage, nutrients and industrial waste into our rivers. For many rivers the low point arrived during the period of 1950s’-1970s’, when rapid economic development overrode environmental concerns and dissolved oxygen concentrations dropped to zero. In these more enlightened times gross river pollution is a thing of the past in the Developed World. However, persistent legacy chemical contaminants can be found in fish long after their discharge ceased. Changes in habitat quality and morphology caused and continue to cause the disappearance of fish species. The range of fish stressors has now increased as temperatures rise and non-native fish introductions bring new diseases. The threat from pharmaceuticals to fish populations remains hypothetical and no studies have yet linked change in fish populations to exposure.

Freshwater aquatic organisms face the challenge of being exposed to a multitude of chemicals discharged by the human population. The objective of this study was to rank metals according to the threat they pose to aquatic organisms. This will contribute to a wider Chemical Strategy for freshwater which will risk rank all chemicals based on their potential risk to wildlife in a UK setting. The method involved comparing information on ecotoxicological thresholds with measured concentrations in rivers. The bioconcentration factor was also considered as a ranking method. The metals; Ag, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn, were analysed using this approach. Triclosan and lindane were used as comparative organic pollutants. Using a range of ranking techniques, Cu, Al and Zn came top of the list of concern, with Cu coming first.

We have become progressively more concerned about the quality of some published ecotoxicology research. Others have also expressed concern. It is not uncommon for basic, but extremely important, factors to apparently be ignored. For example, exposure concentrations in laboratory experiments are sometimes not measured, and hence there is no evidence that the test organisms were actually exposed to the test substance, let alone at the stated concentrations. To try to improve the quality of ecotoxicology research, we suggest twelve basic principles that should be considered, not when presenting findings to the regulators, but at the stage of experimental design. These principles range from accurately defining the exposure through to carefully considering essential aspects of experimental design as well as unbiased analysis and reporting of the results. Although not all principles will apply to all studies, we offer these principles in the hope that they will improve the quality of the science that is presented to regulators. Science is an evidence-based discipline, and it is important that we and the regulators can trust the evidence presented to us. Significant resources often have to be devoted to refuting the results of poor research when those resources could be utilised more effectively.

Differential filtration was used to measure silver (>2 nm) entering and leaving nine sewage treatment plants (STPs). The mean concentration of colloidal (2-450 nm) silver, which includes nanosilver, was found to be 12 ng/L in the influent and 6 ng/L in the effluent. For particulate silver (>450 nm) the mean values were 3.3 µg/L for influent and 0.08 µg/L for effluent. Thus, removal was around 50% and 98% for colloidal and particulate silver respectively. There was no significant difference in performance between the different types of STP investigated (three examples each of activated sludge, biological filter and biological filter with tertiary treatment located across England, UK). In addition, treated sewage sludge samples (biosolids) were taken from several STPs to measure the total silver likely to be discharged to soils. Total silver was 3-14 mg/kg DW in the sludge (median 3.6), which if the sludge were added at the recommended rate to soil, would add 11 µg/kg/yr to the top 20 cm soil layer. Predicted concentrations using the LF2000-WQX model for all the rivers of England and Wales for nanosilver were typically in the 0-1 ng/L range but levels up to 4 ng/L are possible in a high discharge and low flow scenario. Predicted concentrations for the total particulate forms were mostly below 50 ng/L except for a high discharge and low flow scenario where concentrations could reach 135 ng/L.

A simple model was set up to predict estrogen concentrations and endocrine disruption risk in the Yodo River, Japan. This catchment spans the conurbations of Kyoto and Osaka and is the main source of drinking water for Osaka City, Japan. From the river survey data (5 separate occasions between 2005 and 2008), a maximum of 32 g per day estrone (E1) load was observed in the most downstream site of the river. Predicted E1 concentrations were in reasonable agreement with the measurements taken at several points within the basin from a series of sampling campaigns. The predicted concentrations exceeded a net estradiol (E2) equivalent of 1 ng L−1 on only a few occasions, suggesting that only limited endocrine disruption phenomena in fish along the Yodo River is likely. The model was then used to examine the impact on estrogen concentrations and endocrine disruption of a number of different scenarios. It was found that in-river biodegradation had little effect on predicted concentrations and the outcome of endocrine disruption along the catchment. However, reduced sewage treatment removal, as can be experienced in winter in Japan, led to levels of 3.1 ng L−1 E2 equivalents being possible. The reduced river flow in winter in Japan exacerbates the situation as it offers less dilution. It was found that the application of the ozonation process as a tertiary sewage treatment in winter could prevent this higher risk endocrine disruption situation.

Dilution factors are a critical component in estimating concentrations of so-called “down-the-drain” chemicals (e.g., pharmaceuticals) in rivers. The present study estimated the temporal and spatial variability of dilution factors around the world using geographically referenced data sets at 0.5° × 0.5° resolution. Domestic wastewater effluents were derived from national per capita domestic water use estimates and gridded population. Monthly and annual river flows were estimated by accumulating runoff estimates using topographically derived flow directions. National statistics, including the median and interquartile range, were generated to quantify dilution factors. Spatial variability of the dilution factor was found to be considerable; for example, there are 4 orders of magnitude in annual median dilution factor between Canada and Morocco. Temporal variability within a country can also be substantial; in India, there are up to 9 orders of magnitude between median monthly dilution factors. These national statistics provide a global picture of the temporal and spatial variability of dilution factors and, hence, of the potential exposure to down-the-drain chemicals. The present methodology has potential for a wide international community (including decision makers and pharmaceutical companies) to assess relative exposure to down-the-drain chemicals released by human pollution in rivers and, thus, target areas of potentially high risk. Environ Toxicol Chem 2014;33:447–452. © 2013 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial, and no modifications or adaptations are made.