Assessing the Extent of Environmental Risks From Nickel in European Freshwaters: A Critical Reflection of the European Commission's Current Approach

This report collects information on chemical analytical methods for the analysis of the new proposed priority substances (PS) of the European Water Framework Directive (WFD) and some existing PS for which the Environmental Quality Standards (EQS) have been changed under the first review of the PS list. First, analytical “standard” methods (ISO, CEN, US EPA) were searched. Then, the EU Member States (MS) were asked via the Chemical Monitoring and Emerging Pollutants (CMEP) expert group to provide validated “in-house methods” used as a national reference and to report their limits of detection (LODs) or quantification (LOQs). Finally, published literature articles were searched to get an overview of today’s analytical performance. \nCompliance monitoring for the WFD requires the achievement of a LOQ equal or below a value of 30% of the relevant EQS. The achieved method limits of quantification (LOQs) are therefore compared with 30% of the EQS, which is 0.3 × EQS. \nVery low annual average AA-EQS values in the picogram-per-liter (pg/l) concentration range have been set for several of the new proposed PS: For Cypermethrin 80 pg/l (8 pg/l for coastal salt waters), for Dichlorvos 60 pg/l in coastal waters, for Dicofol 32 pg/l in coastal waters, for 17-alpha-ethinylestradiol 35 pg/l (7 pg/l in coastal waters), for 17-beta-estradiol 80 pg/l in coastal waters, and for Heptachlor/-Heptachlorepoxide 0.2 pg/l (10 fg/l in coastal waters). Dicofol and Heptachlor/-Heptachlorepoxide, for which biota EQS have been set (biota EQS: 33 µg/kg, and 6.7 ng/kg, respectively), however, are intended to be analysed in biota. \nMoreover, a very challenging water EQS has been set for the already existing PS Brominated Diphenylethers (BDEs) (49 femtogram-per-liter (fg/l), and 2.4 fg/l in coastal waters). However, it is intended that BDEs be analysed in biota (EQS: 8.5 ng/kg). In addition, the water EQS for Polyaromatic Hydrocarbons (PAHs) has been lowered to 0.17 ng/l, and a biota EQS of 2-10 µg/kg added, which is more easy to reach. \nIn general, it is very difficult to reach with currently available analytical instruments LOQs in the low pg/l concentration range. A possibility could be the use of gas chromatography (GC) with high resolution mass spectrometry (HRMS). This technique, however, is not generally available in normal water monitoring laboratories. Also in the field of liquid chromatography mass spectrometry (LC-MS), instruments with improved sensitivity have become available in the last years. \nMoreover, lower LOQs can be achieved by extracting higher volumes of water (10-1000 liters). These large-volume techniques, however, are very work and time intensive, and very costly, and are therefore not useful for routine WFD compliance monitoring (analysis of one sample per month). \nThe most challenging substances proposed as new PS are: Cypermethrin (EQS: 80 pg/l, and 8 pg/l for coastal salt waters), Dichlorvos (EQS: 60 pg/l in coastal waters), 17-alpha-ethinylestradiol (EQS: 35 pg/l, and 7 pg/l in coastal waters), and 17-beta-estradiol (EQS: 0.4 ng/l, and 80 pg/l in coastal waters). \nDicofol, Dioxins and dioxin-like compounds, Heptachlor/Heptachlorepoxide, Hexabromo-cyclododecane (HBCDD), Perfluorooctane sulfonic acid (PFOS), and the BDEs are intended to be analysed in biota.\nMinor analytical problems could be encountered for the following substances: Aclonifen (EQS: 0.12 µg/l, and 12 ng/l for coastal salt waters), Bifenox (EQS: 12 ng/l, and 1.2 ng/l for coastal waters), Cybutryne (=Irgarol) (EQS: 2.5 ng/l), Diclofenac (EQS: 0.10 µg/l, and 10 ng/l for coastal waters), Quinoxyfen (EQS: 0.15 µg/l, and 15 ng/l for coastal waters), and Terbutryn (EQS: 65 ng/l, and 6.5 ng/l for coastal waters).

BackgroundBioaccumulating contaminants in surface waters are preferably monitored in fish for assessing the related risks to and via the aquatic environment. Consequently, the European Water Framework Directive (WFD) requires a monitoring of certain priority substances such as mercury, polybrominated diphenyl ethers (PBDE), perfluorooctane sulfonic acid and its derivatives (PFOS), hexachlorobenzene (HCB), hexabromocyclododecanes (HBCDD) and polychlorinated dioxins/dioxin-like compounds (dioxins) in freshwater and coastal fish. Tissue levels have to comply with biota environmental quality standards (EQSs) given in Directive 2013/39/EU. EQSs are justified either by risks for human health (assessed on the basis of fillet) or secondary poisoning of wildlife (based on whole fish). To support the practical implementation of the WFD biota monitoring in Germany, comparative investigations of target fish species caught at six sites were performed.ResultsAt each site, at least three fish species listed in a national guidance document were sampled (e.g., chub, roach, bream, perch). Beside biometric data, concentrations of seven priority substances were determined in pooled fillet and carcass samples and whole fish data were calculated. The EQSs for PBDE and mercury were exceeded in nearly all fillet and whole fish samples. PFOS was above the EQS at several sites especially in perch, while HCB exceeded the EQS only at one site (Elbe River). All fillet and whole fish samples complied with the EQSs for dioxins and HBCDD. Based on wet weight concentrations of a homogeneous set of 20 composite sample pairs of 3–5 year-old fish, the following fillet-to-whole fish conversion factors were derived: mercury 0.81, PBDE 5.4, HCB 3.6, PFOS 2.7, dioxins 5.3, and HBCDD 1.8.ConclusionsRecommendations on selection of target fish species, age or tissue given by EU and national guidance documents are practical and feasible. However, further adjustments of the samplings such as the determination of site-specific length–age relationships are required from both ecological and risk assessment perspectives. The derived conversion factors allow the translation of fillet-to-whole fish concentrations (and vice versa), and thus the EQS compliance assessment for the appropriate tissue (fillet for human health, whole fish for wildlife risks) if only one tissue is investigated.

Diclofenac is a nonsteroidal anti-inflammatory human and veterinary medicine widely detected in European surface waters, especially downstream from Wastewater Treatment Plants (WWTPs). Veterinary uses of diclofenac in Europe are greatly restricted, so wastewater is the key exposure route for wildlife. Proposed Environmental Quality Standards (EQS) which include an assessment of toxicity to aquatic organisms are under consideration by the European Commission (EC) to support the aims of the Water Framework Directive (WFD). The EC approach favours the use of a deterministic (single test value and an assessment factor) approach to the derivation of a direct toxicity EQS for diclofenac, resulting in an EQS of 0.040 µg L−1 based on a single mesocosm study. In this paper, we discuss potential issues with this approach with respect to the EC’s own guidance on EQS derivation and derive an evidence-driven alternative EQS of 0.126 µg L−1 using a probabilistic (species sensitivity distribution) approach that accounts for all of the reliable and relevant data and is in accordance with the guidance. Europe-wide freshwater monitoring data for diclofenac are used in an indicative compliance assessment using the EC and the alternative evidence-driven EQS. The implications of using only some data to derive an EQS that does not adhere to the guidance, compared to a guidance-compliant approach that uses all the data available are also discussed.

BackgroundChemical surveillance in surface waters is crucial to identify potential threats to the health of freshwater ecosystems. Usually, the concentrations of pollutants are highly variable over the course of the year and often result in non-normally distributed data sets. Therefore, the European Water Framework Directive recommends measuring, e.g. priority substances at least 12 times a year to achieve an acceptable accuracy level for the estimation of the true mean annual loads. However, in Europe priority substances are often measured much less frequently. In this context, the aim of the present study was to analyze how sample size, temporal variability and skewness of the data sets influence the accuracy of the mean annual load estimation and the assessment of annual average environmental quality standards. For this purpose, sample size simulations using weekly composite samples of benzo(a)pyrene, 4-tert-octylphenol, fluoranthene and di(2-ethylhexyl) phthalate, selected as representatives for priority substances, were carried out.ResultsThe sample size simulations showed two general patterns: the accuracy of the mean annual load estimation increased with increasing sample size and skewness and temporal variability were more apparent in smaller sample sizes. In right-skewed data sets, small sample sizes led, on average, to a systematic underestimation of the true mean annual load whilst in a few cases these led to an overestimation. Although the study was carried out on priority substances, results can be transferable to other pollutants. Furthermore, in small sample sizes a considerable proportion of the simulated means failed to detect annual average environmental quality standard exceedances.ConclusionsThe results of the present study indicate that the usage of small sample sizes is likely to result in an underestimation of the true mean annual pollutant loads in chemical surveillance and scientific research, thus potentially jeopardizing the validity of results. Therefore, it is recommended to avoid the usage of small sample sizes for the determination of mean annual pollutant loads. Furthermore, priority substances should be sampled according to the European Water Framework Directive guidelines at least 12 times/year to improve the assessment of the threat posed by pollutants to freshwater ecosystems in Europe.

Summary recommendations on “Analytical methods for substances in the Watch List under the Water Framework Directive”

The use of a large array of organic and inorganic micropollutants has been leading to an increasing pollution of surface and ground waters (Schwarzenbach et al. 2006). Headwater streams are highly dynamic systems exposed to the transport and dilution of anthropogenic inputs from agricultural land use of their watershed, where periphytic microorganisms (biofilms) play a key role in river functioning. At the basis of these ecosystems, these complex communities composed of photosynthetic organisms (both eukaryotes and cyanobacteria), bacteria, and fungi significantly contribute to primary production, nutrient cycling, and biodiversity (Lear et al. 2012). Thus, biological impairment due to pollution may cause irremediable environmental damage. Improving pesticide assessment tools in surface waters is required to implement appropriate risk mitigation measures and ultimately contribute to the preservation or restoration of aquatic resources water quality. For this purpose, French regulations aim for a 50 % reduction in the use of pesticides within 10 years. Besides, the European Water Framework Directive (WFD) (2000/60/EC) outlines a strategy for the protection and restoration of European waters, which should reach a chemical and ecological ‘good status’ by 2015. The chemical state of French freshwater bodies is more or less extensively monitored (i.e., 5 to 12 spot samplings per year, depending on types of monitoring programs), especially for the molecules defined as ‘priority substances’ (2013/39/EU). To better characterize the occurrence and fate of pesticides, large efforts are made to improve analytical methods in terms of reliability and accuracy. However, the sampling step is also a crucial part of the monitoring process, and the uncertainty attached to it is still largely neglected (Allan et al. 2006). Besides, environmental quality standards (EQS) defined to protect human health or the ecosystem (2013/39/EU) is only a measure of the state of a specific environmental medium, in regard to a specific pollutant. Both improving risk evaluation procedures and characterizing pesticide effects in aquatic environments require the consideration of the interactions of substances in mixtures, such as found in the environment. The flagrant lack of knowledge in this area has been recently stressed by many researchers (Brock et al. 2006; Chevre et al. 2006; Knauert et al. 2009). Complementarily, the impacts of the detected substances have to be evaluated on selected living organisms or ‘key biological indicators’ as defined by the WFD. Biofilm, and in particular its diatom component, is one of these key compartments used in Europe to assess water quality, as an indicator of nutrient enrichment and other pressures (Coste et al. 2009; Kelly et al. 2014; Kelly et al. 2012). To date, diatom-based indices properly diagnose nutrient inputs, but fail to unequivocally assess toxic pollutions. However, the diversity of organisms in biofilms confers to this microbial community a great capacity of response to different environmental factors and thus a potential for contamination assessment. Because of their structural complexity, Responsible editor: Philippe Garrigues

Environmental Quality Standards (EQS) derived under the European Water Framework Directive represent legally binding limits for chemicals in the environment. These EQS are typically based upon ecotoxicity data for the chemical only, following the published EQS Technical Guidance. Recent proposed EQS derivations for the pharmaceuticals carbamazepine and clarithromycin have deviated from this by incorporating ecotoxicity and exposure data for their respective transformation products (TPs). The published Technical Guidance lacks consideration of TPs in EQS derivation, which is manifested in inconsistencies between these two chemicals, such as the use of additional assessment factors and the proposed application of the EQS to the sum of the measured parent and TPs rather than just the parent chemical. To resolve these inconsistencies, we have developed an evidence-driven approach to illustrate how TP considerations could be incorporated into the EQS derivation process in a repeatable and transparent manner, and to utilise all the relevant and reliable data for both effects and exposures. As the precedent has now been set by the European Commission that TPs may be considered in EQS derivations, we recommend that this approach be further developed and incorporated into an upcoming revision to the Technical Guidance to ensure that future derivations by regulators and non-regulatory environmental risk assessors and practitioners are consistent and scientifically robust.

Integrating long-term water and sediment pollution data, in assessing chemical status within the European Water Framework Directive

BackgroundThe European Water Framework Directive (WFD) requires the monitoring of biota—preferably fish—to check the compliance of tissue concentrations of priority substances (PS) against substance-specific environmental quality standards (EQSs). In monitoring programs, different fish species are covered, which often are secondary consumers with a trophic level (TL) of about 3. For harmonization, a normalization of monitoring data to a common trophic level is proposed, i.e., TL 4 (predatory fish) in freshwaters, so that data would be sufficiently protective. For normalization, the biomagnification properties of the chemicals can be considered by applying substance-specific trophic magnification factors (TMFs). Alternatively, TL-corrected biomagnification factors (BMFTLs) may be applied. Since it is impractical to derive site-specific TMFs or BMFTLs, often data from literature will be used for normalization. However, available literature values for TMFs and BMFTLs are quite varying. In the present study, the use of literature-derived TMFs and BMFTLs in data normalization is studied more closely.ResultsAn extensive literature evaluation was conducted to identify appropriate TMFs for the WFD PS polybrominated diphenyl ethers (PBDE), hexachlorobenzene, perfluorooctane sulfonate (PFOS), dioxins and dioxin-like compounds (PCDD/F + dl-PCB), hexabromocyclododecane, and mercury. The TMFs eventually derived were applied to PS monitoring data sets of fish from different trophic levels (chub, bream, roach, and perch) from two German rivers. For comparison, PFOS and PBDE data were also normalized using literature-retrieved BMFTLs.ConclusionsThe evaluation illustrates that published TMFs and BMFTLs for WFD PS are quite variable and the selection of appropriate values for TL 4 normalization can be challenging. The normalized concentrations partly included large uncertainties when considering the range of selected TMFs, but indicated whether an EQS exceedance at TL 4 can be expected. Normalization of the fish monitoring data revealed that levels of substances accumulating in the food web (TMF or BMF > 1) can be underestimated when relying on fish with TL < 4 for EQS compliance assessment. The evaluation also revealed that TMF specifically derived for freshwater ecosystems in Europe would be advantageous. Field-derived BMFTLs seemed to be no appropriate alternative to TMFs, because they can vary even stronger than TMFs.

Determination of tributyltin in whole water matrices under the European Water Framework Directive

Environmental quality standards (EQS) derived under the European Water Framework Directive are legally binding and enshrined in individual European Member State Country national legislation. These EQS are derived following well-established guidance documents. In 2013, EQS for nickel were derived for freshwaters to be protective against long- and short-term exposures, at 4 and 34 µg L-1, respectively. The value for long-term exposures uses chronic ecotoxicity data and accounts for bioavailability, whereas the short-term value uses acute data and does not account for bioavailability. In 2022, the European Commission revised these values as part of the ongoing legislative process. Despite an increase in available data for both chronic and acute ecotoxicity endpoints, the update and development of chronic and acute biotic ligand models (BLMs) published in peer-reviewed literature, and the accessibility of vastly more monitoring data (used in the European EQS derivation), the values for the nickel EQS were reduced by increasing the assessment factors to account for increases in apparent uncertainties. The Commission's 2022 derivation failed to consider additional chronic data for more than 20 species as well as the updated and new acute and chronic BLMs. As a result, the derived nickel EQS is limited in its applicability and relevance to European freshwater ecosystems, as illustrated in practice by the observation that monitoring sites can comply with the chronic EQS but fail the acute EQS. Here, we provide an explanation as to why this has occurred and detail what it means for the risk assessment of nickel in European Member State freshwaters. Finally, we outline a path forward that should be relevant for any risk-based and evidence-driven regulatory framework and acknowledging that political decisions are part of the process, but that these should be separate and after scientific aspects are undertaken.

Diclofenac is a nonsteroidal anti-inflammatory human and veterinary medicine widely detected in European surface waters, especially downstream from Wastewater Treatment Plants. With some notable exceptions, veterinary uses of diclofenac in Europe are greatly restricted, so wastewater is the key Europe-wide exposure route for wildlife that may be exposed via the aquatic environment. Proposed Environmental Quality Standards (EQS) which include an assessment of avian exposure from secondary poisoning are under consideration by the European Commission (EC) to support the aims of the Water Framework Directive (WFD). In this paper we summarise information on avian toxicity plus laboratory and field evidence on diclofenac bioaccumulation and bioconcentration in avian food items. A safe diclofenac threshold value for birds of 3 μg kg−1 wet weight in food was previously derived by the European Medicines Agency and should be adopted as an EQS under the WFD to maintain consistency across European regulations. This value is also consistent with values of 1.16–3.99 µg kg−1diet proposed by the EC under the WFD. Water-based EQS of 5.4 or 230 ng L−1 in freshwater are derived from these dietary standards, respectively, by the EC and by us, with the large difference caused primarily by use of different values for bioaccumulation. A simple assessment of potential water-based EQS compliance is performed for both of these latter values against reported diclofenac concentrations in samples collected from European freshwaters. This shows that exceedances of the EC-derived EQS would be very widespread across Europe while exceedances of the EQS derived by us are confined to a relatively small number of sites in only some Member States. Since there is no evidence for any declines in European waterbird populations associated with diclofenac exposure we recommend use of conservative EQS of 3 µg kg−1diet or 230 ng L−1 in water to protect birds from diclofenac secondary poisoning through the food chain.

BackgroundThis study aims to describe and test a tiered approach for assessing compliance to Environmental Quality standards (EQSs) for priority substances in biota in line with the European Water Framework Directive. This approach is based on caged gammarids and trophic magnification factors (TMFs) at the first tier, with fish analyzed at the second tier at sites predicted to exceed the EQS at the first tier. A dataset was implemented by monitoring perfluorooctane sulfonate (PFOS) in caged gammarids exposed at 15 sites in French rivers, and in fish muscle and rest-of-body from the same sites. Isotopic ratios (δ13C and δ15 N) were also measured in gammarids and fish. Two scenarios were developed to compare measured PFOS concentrations in fish against predicted concentrations based on measures in caged gammarids and TMFs. Scenario (1) compared measured PFOS concentrations in fish fillets with predicted PFOS concentrations based on measured concentrations in caged gammarids and δ15 N. Scenario (2) tested whether or not EQS exceedance was correctly predicted based on measured concentrations in caged gammarids and trophic levels (TLs) from wild fish and gammarid populations.Resultsδ13C and δ15 N variations showed that caged gammarids used local food resources during exposure in the field. PFOS concentrations in gammarids were fairly variable through time at each site. In fish, concentrations ranged from < 1 to 250 ng g−1 (wet weight). After adjustment to the TL at which the EQS is set, 12 sites were above the EQS for PFOS. In scenario (1), predicted concentrations were almost correct at 7 sites out of 15. Most incorrect predictions were overestimations that were slightly improved by applying a lower (neutral) TMF. In scenario (2) we tested several variants for parameters involved in the predictions. The most efficient combination yielded two wrong predictions out of 15. This result was obtained with a higher (more conservative) TMF value, mean concentrations in gammarids from several field exposures during a year, and a TL for gammarids at the median of the distribution in French rivers.ConclusionThe proposed tiered approach was thus efficient. However, the number of sites was relatively limited, and the dataset was biased towards EQS exceedance. The tiered approach warrants further validation.

Leverett et al. commented on the Environmental quality standard (EQS) for diclofenac derived under the European Water Framework Directive (Leverett et al. Environ Sci Eur 33: 133, 2021 https://doi.org/10.1186/s12302-021-00574-z). They postulated that the derived EQS value for diclofenac is not conducted according to the EQS Technical Guidance but rather using data of poor quality and relevance. Consequently, the authors suggested to use their alternative derived value instead. It is to be noted that the process for the EQS derivation for diclofenac is still ongoing and not finalized, and that as a consequence, any critical analysis is very premature. In general, within the current European Commission process, EQS value proposals are derived by expert groups led by the Joint Research Centre. In the specific case for diclofenac, Leverett and co-authors have also been actively involved as experts. This response to Leverett et al. (Environ Sci Eur 33:133, 2021) aims to clarify the reasoning-behind the proposal from a scientific point of view.

Needs for reliable analytical methods for monitoring chemical pollutants in surface water under the European Water Framework Directive