Semipolar polycyclic aromatic compounds: Identification of 15 priority substances and the need for regulatory steps under REACH regulation

Abstract

Semipolar polycyclic aromatic compounds (sPACs) are frequently found in association with homocyclic polycyclic aromatic hydrocarbons (PAHs) in substances of unknown or variable composition, complex reaction products, or biological materials (UVCBs) from coal or crude oil and products derived thereof. However, major information deficiencies exist with regard to their prevalence and their toxicological and ecotoxicological potential, persistency, and bioaccumulation characteristics. Therefore, in this work, the environmental concern and relevance of sPACs was addressed in a general, stepwise approach. First, a large list of sPACs was collected and subsequently refined by assessing their persistence, bioaccumulation, and toxicity (PBT) properties by quantitative structure-activity relationship (QSAR) methods and their relevance by determining their respective frequency of occurrence. In this way, 15 priority sPACs were identified. These 15 priority sPACs were further characterized in detail with respect to their ecotoxicological properties, environmental behavior, carcinogenicity, and genotoxicity attributes. All of these 15 substances were quantified in distillate or product samples. In the next step, some principles for nomination of indicator substances, indicative for the overall content of sPACs, are derived. Data gaps on ecotoxicological endpoints preclude final conclusions, but the respective necessary supplemental tests were identified. Five of the 15 sPACs were tentatively characterized as potential substances of very high concern (SVHC) for the environment. The overall results of this study also clearly show that regulatory risk management of homocyclic PAHs within the European Regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) does not address the environmental concern created by sPACs within UVCBs from coal or crude oil. The study proves the need for additional regulatory steps under REACH and suggests indicator substances for their enforcement.

Final report: Testing a procedure for the identification of emerging chemical risks in the food chain. External Scientific Report. OC/EFSA/SCER/2014/03

“…Model predictions of BIOWIN3, BIOWIN5 and BIOWIN6 have shown high accuracy to predict a chemical to be 'not readily degradable' (Tunkel et al, 2000;Boethling et al, 2004;Schwarz et al, 2014). Boethling et al (2004) stated that an overall good battery approach for the prediction of ready biodegradability was the combination of BIOWIN3 and BIOWIN 5 for US pre-manufacture notice substances (PMN substances) and the combination of BIOWIN3 and BIOWIN6 for pharmaceuticals.…”

reply

“…whether the compound of interest is sufficiently similar to the compounds used to train the model (Netzeva et al, 2005;Sushko et al, 2010;Sahigara et al, 2012). So far, as noted previously, the use of in silico methods for the toxicological assessment of aerosol organic compounds has been limited and restricted to specific chemical classes like PAHs (Papa et al, 2008;Schwarz et al, 2014). In this study, we perform a proof-ofconcept evaluation on the information retrieved from in silico methods specifically applied to a subset of measured compounds attributed to multiple sources of SOA.…”

reply to Referee 1

“…whether the compound of interest is sufficiently similar to the compounds used to train the model (Netzeva et al, 2005;Sushko et al, 2010;Sahigara et al, 2012). So far, as noted previously, the use of in silico methods for the toxicological assessment of aerosol organic compounds has been limited and restricted to specific chemical classes like PAHs (Papa et al, 2008;Schwarz et al, 2014). In this study, we perform a proof-ofconcept evaluation on the information retrieved from in silico methods specifically applied to a subset of measured compounds attributed to multiple sources of SOA.…”