International scientists' priorities for research on pharmaceutical and personal care products in the environment.

Pharmaceuticals and personal care products (PPCPs) are widely discharged into the environment via diverse pathways. The effects of PPCPs in the environment have potentially important human and ecosystem health implications, so credible, salient, and legitimate scientific evidence is needed to inform regulatory and policy responses that address potential risks. A recent "big questions" exercise with participants largely from North America identified 22 important research questions around the risks of PPCP in the environment that would help address the most pressing knowledge gaps over the next decade. To expand that analysis, we developed a survey that was completed by 535 environmental scientists from 57 countries, of whom 49% identified environmental or analytical chemistry as their primary disciplinary background. They ranked the 22 original research questions and submitted 171 additional candidate research questions they felt were also of high priority. Of the original questions, the 3 perceived to be of highest importance related to: 1) the effects of long-term exposure to low concentrations of PPCP mixtures on nontarget organisms, 2) effluent treatment methods that can reduce the effects of PPCPs in the environment while not increasing the toxicity of whole effluents, and 3) the assessment of the environmental risks of metabolites and environmental transformation products of PPCPs. A question regarding the role of cultural perspectives in PPCP risk assessment was ranked as the lowest priority. There were significant differences in research orientation between scientists who completed English and Chinese language versions of the survey. We found that the Chinese respondents were strongly orientated to issues of managing risk profiles, effluent treatment, residue bioavailability, and regional assessment. Among English language respondents, further differences in research orientation were associated with respondents' level of consistency when ranking the survey's 15 comparisons. There was increasing emphasis on the role of various other stressors relative to PPCPs and on risk prioritization as internal decision making consistency increased. Respondents' consistency in their ranking choices was significantly and positively correlated with SETAC membership, authors' number of publications, and longer survey completion times. Our research highlighted international scientists' research priorities and should help inform decisions about the type of hazard and risk-based research needed to best inform decisions regarding PPCPs in the environment. Disciplinary training of a scientist or engineer appears to strongly influence preferences for research priorities to understand PPCPs in the environment. Selection of participants and the depth and breadth of research prioritization efforts thus have potential effects on the outcomes of research prioritization exercises. Further elucidation of how patterns of research priority vary between academic and government scientists and between scientists and other government and stakeholders would be useful in the future and provide information that helps focus scientific effort on socially relevant challenges relating to PPCPs in the environment. It also suggests the potential for future collaborative research between industry, government, and academia on environmental contaminants beyond PPCPs.