Alternative objectives : time extensions and less stringent objectives

The Water Framework Directive (2000/60/EC) (WFD) establishes a suite of environmental objectives for groundwater. In implementing the Directive and producing the first River Basin Management Plans, Member States have had to identify whether the these objectives are being met. If this assessment has shown that one or more of the objectives for groundwater is not being met, or is at risk of being failed, programmes of measures must be implemented to ensure that all relevant environmental objectives are met within six years – the publication date of the next River Basin Management Plan (22nd December, 2015). In reality, especially for groundwater, achieving all the relevant objectives in such a short timescale may not be possible or practical. The WFD recognises this and allows for an extension of the deadline (beyond 2015) for the purposes of a phased achievement of the environmental objectives. This is provided that there is no further deterioration in status (Article 4.4). Any such extension is limited to a maximum of two further river basin cycles (12 years) except where natural conditions mean that objectives can still not be achieved. A further provision is made for the situation where a water body is so badly affected by human activity or where natural conditions mean that achievement of the objectives(s) would be infeasible or disproportionally expensive. In these cases less stringent objectives (relative to those defined in Article 4.1) can be set, provided that there is the least possible deviation from good status conditions. Where extended deadlines or less stringent objectives have been proposed, Member States must provide an explanation and justification in the River Basin Management Plan. In the case of extended deadlines, a timetable for implementation of measures and the achievement of objectives must also be provided. This paper provides an overview of the approach used in England and Wales for identifying programmes of measures for groundwater, predicting outcomes and setting alternative objectives in relation to groundwater quality. Similar approaches were used for quantitative (water resource) aspects and also for surface water bodies

Proportional contributions to organic chemical mixture effects in groundwater and surface water

Semi-quantitative GC-MS and LC-MS measurements of organic chemicals in groundwater and surface waters were used to assess the overall magnitude and contribution of the most important substances to calculated mixture hazard. Here we use GC-MS and LC-MS measurements taken from two separate national monitoring programs for groundwater and surface water in England, in combination with chronic species sensitivity distribution (SSD) HC50 values published by Posthuma et al. (2019, Environ. Toxicol. Chem, 38, 905–917) to calculate individual substance hazard quotients and mixture effects using a concentration addition approach. The mixture analysis indicated that, as anticipated, there was an increased hazard from the presence of a cocktail of substances at sites compared to the hazard for any single chemical. The magnitude of the difference between the hazard attributed to the most important chemical and the overall mixture effect, however, was not large. Thus, the most toxic chemical contributed ≥ 20% of the calculated mixture effect in >99% of all measured groundwater and surface water samples. On the basis of this analysis, a 5 fold assessment factor placed on the risk identified for any single chemical would offer a high degree of in cases where implementation of a full mixture analysis was not possible. This finding is consistent with previous work that has assessed chemical mixture effects within field monitoring programs and as such provides essential underpinning for future policy and management decisions on how to effectively and proportionately manage mixture risks

Developing a groundwater watch list for substances of emerging concern: a European perspective

There is growing concern globally about the occurrence of anthropogenic organic contaminants in the environment, including pharmaceuticals and personal care products. This concern extends to groundwater which is a critical water resource in Europe and its protection is a priority for the European Commission and European Union (EU) Member States. Maintaining good groundwater status supports improved public health, economic growth and sustains groundwater dependant ecosystems. A range of measures have been introduced for regulating several substances that have impacted groundwater (e.g. nitrate and pesticides). However, these measures only cover a small fraction of anthropogenic substances that could pollute groundwater. Monitoring for these unregulated substances is currently very limited or not carried out at all. Therefore, a coordinated European-wide approach is needed to identify, monitor and characterise priority substances or groups of substances that have the potential to pollute groundwater. This evidence base is critical for policy development and controls on these currently unregulated substances. The European Commission highlighted this as a need during the review of the EU Groundwater Directive Annexes in 2014, when the requirement to develop a Groundwater Watch List (GWWL) was established. This paper describes the approach that has been developed through a voluntary initiative as part of the EU CIS Working Group Groundwater to establish the voluntary EU GWWL. The process for developing the GWWL is one that has brought together researchers, regulators and industry, and is described here for the first time. A summary of the key principles behind the methodology is presented as well as results from pilot studies using per- and polyfluoroalkyl substances and pharmaceuticals. These explore and support the viability of the GWWL process, an important step towards its adoption and its future use for groundwater protection across Europe

Worst-case ranking of organic chemicals detected in groundwaters and surface waters in England

The Environment Agency has been using Gas Chromatography–Mass Spectrometry (GC–MS) and Accurate-mass Quadrupole Time-of-Flight (Q-TOF) / Liquid Chromatography-Mass Spectrometry (LC-MS) target screen analysis to semi-quantitatively measure organic substances in groundwater and surface water since 2009 for GC–MS and 2014 for LC-MS. Here we use this data to generate a worst-case “risk” ranking of the detected substances. Three sets of hazard values relating to effects on aquatic organisms, namely Water Framework Directive EQSs, NORMAN Network PNECs (hereafter NORMAN PNEC) and chronic Species Sensitivity Distribution (SSD) HC50s from Posthuma et al., (2019) were used for the assessment. These hazard values were compared to the highest measured concentration for each chemical to generate a worst-case hazard quotient (HQ). Calculated HQs for each metric were ranked, averaged and multiplied by rank for detection frequency to generate an overall ordering based on HQ and occurrence. This worst-case approach was then used to generate ranking lists for GC–MS and LC-MS detected substances in groundwater and surface water. Pesticides in the top 30 overall ranked list included more legacy pesticides in groundwater and more current use actives in surface water. Specific uses were linked to some high rankings (e.g. rotenone for invasive species control). A number of industrial and plastics associated chemicals were ranked highly in the groundwater dataset, while more personal care products and pharmaceuticals were highly ranked in surface waters. Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) compounds were commonly highly ranked in both environmental compartments. The approach confirmed high rankings for some substance (e.g. selected pesticides) from previous prioritization exercises, but also identified novel substance for consideration (e.g. some PFAS compounds and pharmaceuticals). Overall our approach provided a simple approach using readily accessible data to identify substances for further and more detailed assessment