resorcinol; 1,3-benzenediol

Short-term toxicity to fish

Description of key information

Acute aquatic toxicity data are available in fish following protocols similar to those of guideline studies.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

26.8 mg/L

Additional information

Acute aquatic toxicity data are available in fish following protocols similar to those of guideline studies with the key study selected on the grounds of the study with the lowest reliable LC50. 

The 96-hour LC₅₀s of resorcinol in fathead minnows (Pimephales promelas) ranged from 26.8 mg/L (mean measured) to 100 mg/L (nominal) under flow through conditions; under static conditions the 96-hour LC₅₀ ranged from 40 – 60 mg/L. In a flow through test, two individual tests were conducted in which groups of 10 fish were exposed per test concentration (Koppers Company, 1981).  In test 1, 10 fish per test group were exposed to mean measured concentrations of 0, 16.2, 25.8, 34, 39.6 and 46.4 mg/L and in test 2 to concentrations of 0, 12.8, 22.8, 32, 40 and 49.8 mg/L. The 96 hr LC₅₀s were = 29.5 (mean measured) and 26.8 (mean measured) mg/L for tests 1 and 2, respectively. These results are consistent with those reported for the purer form of resorcinol. In a study conducted using Resorcin DS technical grade (99% resorcinol), 10 fish per test concentration were exposed to 0, 10, 25, 31.5, 40, 63 and 100 mg/L (nominal) (Hoechst AG, 1981).   In the 31.5 to 100 mg/L groups 5 fish died up to 95 hours after addition of the test substance, with the following symptoms:  surface swimming, uncoordinated swimming movements, drifting in a lateral position, hyper-reflexivity, reduced frequency of gill action.  The fish in the 25 and 10 mg/L groups did not differ in their behavior from those in the control groups. The fish in the 100 mg/L group presented punctuate red flecks on the body surface.  Dissection showed no macroscopically visible changes in all test groups.  The resulting 96 hr LC₅₀ was 34.7 mg/L (nominal) and the NOEC was 25 mg/L (nominal).

In a 3-day fish embyo test, exposure of zebrafish embryos to the maximum tolerated concentration of resorcinol (200 mg/l) resulted in a significantly decreased concentration of interfollicular T4 hormone content (IT4C) compared to the control (p<0.05). Based on these results, resorcinol was considered to be a thyroid gland disruptor (TGFD). In a further experiment examining the concentration-response of this effects an EC50 of 82 µM was reported, based on decreased IT4C. An LC50 of 5003 µM was also reported, resulting in a Thyroid disrupting Index (TDI; LC50/EC50) of 61.

 

In a three day fish embryo test, exposure of transgenic zebrafish embryos to a range of resorcinol concentrations resulted in induction of thyroglobulin expression, compared to the control, based on the concentration-dependent increase of the tg;m Cherry fluorescence. Based on these results an EC50 of 3.4 µmol/l was reported along with a BMD20 of 0.663 µmol/l. An LC50 of 5197 µmol/l was also given, resulting in a Thyroid Disrupting Index (TDI: LC50/EC50) of 1529 (Jarque et al 2018).