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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

The 96-h LC50 value in fish (rainbow trout) is 3.9 mg/L (measured).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Dose descriptor:
Effect concentration:
3.9 mg/L

Additional information

Four acute fish studies are available for evaluation. All were conducted in accordance with GLP and generally accepted test guidelines.

The 96-h flow-through test on Oncorhynchus mykiss is considered to best take into account the test substance’s degradation in water which was substantiated by substance recoveries throughout the test (Haskell Laboratory, 1990). Furthermore, this study was performed with the 'cold-water' fish species rainbow trout, whereas the other studies were performed with 'warm-water' fish species (fathead minnow and medaka). Although all studies were performed using OECD preferred species, in general for European industrial chemical risk assessment, cold-water species are preferred. Therefore, this study was selected as the key study and the 96 -h LC50 of 3.9 mg/L (based on measured concentrations) is considered for assessment. Two studies were conducted using a static test design (Haskell Laboratory, 1985a/b). In these studies, recoveries of nominal concentrations at the start of the test (t = 0) were already so low that in most cases analysis of concentrations was not performed at the end of exposure (or at renewals). The fourth study was conducted using a semi-static design. In this study also the concentration of the substance was not well maintained throughout the whole duration of the test (Japan food research laboratories, 2003).

In the meanwhile, initiatives have been taken to run ecotoxicity testing with known degradation products of PPD. An acute toxicity test with the Bandrowski's base has been conducted but no final report is yet available. From the preliminary data from this fish embryo acute toxicity test, a LC50 of 3.478 -6.303 mg/L (nominal) was calculated, the range depending on concentration and age of stock solutions used.