The European chemical industry is highly regulated, both internally and externally, with a range of guidelines and legislative instruments requiring environmental testing and assessment of new products to ensure environmental (and human) safety prior to market authorisation in the European Union (EU) (Hommen et al, 2010). Whilst regulations are highly consistent across chemical sectors, environmental testing may be tailored for different classes of chemicals, according to their inherent risks to the environment. In each case a tiered environmental risk assessment (ERA) is performed, beginning with the estimation of exposure profiles based on chemical use, volumes and/or physico-chemical properties. Predicted or measured chemical exposure concentrations may then be compared to predicted or measured effects on environmentally relevant and/or sensitive test species, while also taking into account chemical mode of action and potency, including the potential for bioconcentration and secondary poisoning (Hommen et al, 2010).
Despite highly developed environmental principles (Table 3.1) and internationally standardised test methods (OECD, 2015), environmental protection goals for chemical registration remain vague, such as requiring prevention of ‘unacceptable’ or ‘adverse’ impacts on ‘biodiversity’ and ‘ecosystems’ or the ‘environment as a whole’. Due to the complexity of ecosystems these high-level goals have not been adequately addressed by current regulations and ERA guidance documents, leading regulators to ‘err on the side of caution’. The widespread adoption of this overarching ‘precautionary principle’ (UN Rio Declaration, 1992b) has led to the application of assessment (uncertainty) factors in order to extrapolate from the most sensitive test species to protect the theoretically most sensitive species in the field, with the intention of protecting ‘ecosystems’ and the ‘environment as a whole’.
Uncertainties in ERA are attributable to: i) natural background variability in the environment; ii) representation of multiple chemical exposure profiles; iii) extrapolation of chemical effects from individual laboratory test organisms to wild populations; iv) failure to account for ecological factors, including interactions between species and between physical, chemical and biological stressors (Table 1.1, after Chapman, 2002; Hommen et al, 2010; SCHER/SCENIHR/SCCS, 2012).
Table 3.1: Environmental principles adopted in the prospective and retrospective ERA of chemicals – requiring environmental protection goals at different levels of biological organisational (underlined) (Adapted from Brock et al, 2006; Beder, 2006)
Figure 3.1: EU environmental legislation and conventions relating to chemicals relating to Appendix C Tables: C1.1 (red boxes); C1.2 (red/green boxes); C1.3 (green boxes)