Effect of test concentration in the ready biodegradability test for chemical substances: Improvement of OECD test guideline 301C

Autor: Ryosuke Nabeoka, Tomohiko Yoshida, Takashi Kameya, Takakazu Kayashima, Masanori Taruki
Rok vydání: 2015
Předmět:
Zdroj: Environmental Toxicology and Chemistry. 35:84-90
ISSN: 0730-7268
Popis: In Japan, understanding the environmental persistence of chemicals is very important for risk assessment, and ready biodegradability tests are mainly conducted according to the Organisation for Economic Co-operation and Development Test Guideline 301C (TG301C). However, the highest test concentration specified in TG301C, 100 mg/L, may cause microbial toxicity and incomplete biodegradation. We performed TG301C tests at test concentrations of 30 mg/L for 13 substances that were readily biodegradable in ready biodegradability tests but not in TG301C tests. Of the five substances with potential to cause microbial toxicity at 100 mg/L, the percentage biodegradation of sodium dimethyldithiocarbamate, 4-chloro-3-cresol (CC), thymol (THY), and p-tert-butyl-α-methylbenzenepropionaldehyde measured by biochemical oxygen demand (BOD) increased in the TG301C test at 30 mg/L, suggesting a reduction in toxicity effects. Furthermore, CC and THY met the criteria for ready biodegradability, which are more than 60% of biodegradation by BOD and 10-d window. Of the eight substances with low potential of causing microbial toxicity at 100 mg/L, the percentage biodegradation of only 2-(diethylamino)ethanol increased in the TG301C test at 30 mg/L. Employing a lower test concentration in the standard TG301C test will contribute to improvement of consistency between results of a TG301C test and other ready biodegradability tests. This article is protected by copyright. All rights reserved
Databáze: OpenAIRE