| This study aimed to collect fundamental information on environmental risks posed by Class 1 chemicals under the Japanese Pollutant Release and Transfer Register (PRTR) system. The concentration of the substances in treated wastewater was estimated using the publicly-available information in the PRTR system. Initial ecological and human health risk assessments were performed by comparing the estimated concentration and existing toxicity indexes on the basis of a hazard quotient (HQ). The results showed that linear alkylbenzene sulfonate (LAS) and its salts had the highest concentrations (166 μg/L). Thirty-six (e.g., hydrazine) and 11 chemicals (e.g., glutaraldehyde) had high HQ values (≧0.1) in initial ecological and human health risk assessments, respectively. Using comparisons between a previous study and this study, an interannual variability of high HQ value chemicals revealed that the composition of chemicals for ecological risk was similar for the different periods; however, it was different for human health risk. Further monitoring and development of countermeasures against the chemicals are required to avoid ecological and health risks. |
