SummaryThe Evidence-based Toxicology Collaboration (EBTC)

Transparency and documentation of the decision process are at the core of a credible risk assessment and, in addition, are essential in the presentation of a weight of evidence (WoE)-based approach. Lack of confidence in the risk assessment process (as the basis for a risk management decision), beginning with evaluation of raw data and continuing through the risk decision process, is largely because of issues surrounding transparency. There is a critical need to implement greater transparency throughout the risk assessment process, and although doing so will not guarantee the correctness of the risk assessment or that all risk assessors come up with the same conclusions, it will provide essential information on how a particular conclusion or decision was made, thereby increasing confidence in the conclusions. Recognizing this issue, the International Life Sciences Institute Health and Environmental Sciences Institute convened a multisector committee tasked with discussing this issue and examining existing guidance and recommendations related to transparency in risk assessment. The committee concluded that transparency is inextricably linked to credibility: credibility of the data, credibility of the risk assessment process, and credibility of the resulting decision making. To increase this credibility, existing guidance concerning criteria elements of transparency related to the risk assessment process must be more widely disseminated and applied, and raw data for studies used in human health and environmental risk assessment must be more widely available. Finally, the decision-making process in risk management must be better documented and a guidance framework established for both the process itself and its communication to the public.

Produced water is the largest waste stream associated with oil and gas exploration and production operations. Most produced water generated onshore is managed by permitted injection in deep underground wells, but alternative disposal options including reuse are increasingly being considered. However, insufficient understanding of the composition and toxicity of produced water imposes significant constraints on effective management of potential short‐term and long‐term risks associated with such alternative uses. As interest builds for management options, such as surface discharge, livestock watering, irrigation, and other industrial uses, research is needed to assess produced‐water hazards and exposures to both humans and the environment. This challenge affords an opportunity to capitalize on emerging risk assessment tools. Innovative and comprehensive approaches to filling data gaps and assessing produced water risks will be imperative. A group of experts from industry, academia, and government were assembled to define research needs to support objective decision making on the acceptability, or lack thereof, of produced water disposal alternatives. Presented here are key outcomes from that workshop and recommendations for a research framework to assess toxicity of produced water and associated risks from above ground discharge and reuse options. Integr Environ Assess Manag 2019;15:677–682. © 2019 SETAC.

Isolated case reports suggest that dermal contact with some phthalate esters may result in skin sensitization. This issue was investigated in guinea pig sensitization tests, but the results were inconclusive. Consequently, 7 dialkyl phthalate esters, (diisohexyl, diisoheptyl, di(2-ethylhexyl), diisononyl, diisodecyl, diundecyl and ditridecyl phthalates), ranging in carbon number from C6 to C13, were tested in a 104-person panel human repeated insult patch test (HRIPT) using the modified Draize procedure. Test concentrations of 100% were selected for the induction and challenge phases of the HRIPT based upon a 24-h occluded irritation test on 15 panelists. Under the conditions of this HRIPT, no evidence of dermal irritation or sensitization for any of the 7 phthalate esters was observed in the 104-person panel. These HRIPT data provide evidence for the lack of experimental skin sensitization potential for the phthalate esters tested.

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