Phenol, 4-nonyl-, branched

Long-term toxicity to aquatic invertebrates

Description of key information

Cornement (2020) provided a 28 -day EC10 (reproduction) of 0.004 mg/l (and NOEC of 0.006 mg/l) nonylphenol as a measured concentration for the mud snail, Potamopyrgus antipodorum in accordance with OECD 242 Guideline methodology and GLP certification.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC10

Effect concentration:

0.004 mg/L

Marine water invertebrates

Marine water invertebrates

Dose descriptor:

NOEC

Effect concentration:

0.009 mg/L

Additional information

The 21-day study by Comber et al (1993) was previously selected as the key study because the study provided NOEC values for standard long-term test endpoints of survival and reproduction for the preferred test organism, Daphnia magna, and was adequately documented and performed according to Guidelines. The NOEC value of 0.024 mg/l was previously selected as the key value from the Comber et al (1993) study. A new study on the mud snail Potamopyrgus antipodarum by Cornement (2020) reported two endpoints with more sensitive NOEC values than the Daphnia magna study by Comber et al (1993) and is now the Key Study for the long-term toxicity to invertebrates endpoint. The most sensitive endpoints for this key study were reported as a 28-day NOEC for reproduction in P. antipodarum of 0.006 mg/l and an EC10 of 0.0041 mg/l. The NOECs for morphology (shell length) and mortality were also 0.0147 and 0.0247 mg/l for P. antipodarum in the same study. These are all reported as time-weighted average measured concentrations of the active ingredient.

The reported NOEC of 0.05 mg nonylphenol/L by Baldwin et al (1997) and 0.06 mg nonylphenol/L by Brennan et al (2006) for inhibition of reproduction to the preferred test species D. magna were similar findings to the Comber et al (1993) former key study; with Sun and Gu (2005) reporting 0.013 mg nonylphenol/L (no analytical monitoring) at the low end of the range and Brooke (1993) and Spehar et al (2010) reporting 0.12 mg/L at the high end of the range.

Long-term exposure of nonylphenol to aquatic invertebrates included reliable supporting studies covering several different freshwater taxa including the preferred test organism, D. magna. Also, several reliable studies for marine organisms were available, such as Americamysis bahia (Kuhn et al 2001, Hirano et al 2009); Tisbe batagliai (Bechmann, 1999); Tigriopus japonicus (Marcial et al, 2003) and Lytechinus pictus (Taylor, 2019). An additional new study by Taylor (2019) on the sea urchin Lytechinus pictus reported a NOEC for fertilisation success of 0.85 mg/l, which is less sensitive than most of the results for other marine organisms.

The range of NOEC values for survival was from 0.025 mg nonylphenol/L (Sun and Gu, 2005) to 0.04 mg nonylphenol/L (Brennan et al 2006) for D. magna. The NOEC for reproduction ranged from 0.001 mg nonylphenol/L for Ceriodaphnia dubia (7 days) (Isidori et al 2006) to 0.116 mg/l and >0.1 mg nonylphenol/L reported for 21-day tests with D. magna by Brooke (1993) and Scholz (1992), respectively and 0.05 mg/l for D. galeata (Tanaka and Nakanishi, 2002). Studies on other freshwater species determined a NOEC for survival of 0.042mg/l for Chironomus tentans (Kahl et al. 1997); a NOEC of >0.2352mg/l for the sediment organism Caenorhabditis elegans (Hoss et al, 2002); a NOEC of >0.005mg/l (the highest concentration tested) for Gammarus fossarum (Geffard, 2010); an EC10 of 0.68mg/l for long term mortality attachment and siphon extension in the freshwater mussel species, Dreissena polymorpha (Quinn, 2006).

For the marine species, the NOEC of 0.0095 mg nonylphenol/L for reproduction (Kuhn et al 2001) of A. Bahia, 0.02 mg nonylphenol/L mortality and reproduction of Tisbe batagliai (Bechmann, 1999) and 0.85mg/l for reproduction of Lytechnius pictus (Taylor, 2019) were within the ranges reported for freshwater organisms.

Insufficient data were available to confirm which of the species tested was most sensitive, but the findings of Isidori et al (2006) suggest that inhibition of reproduction for C. dubia can occur at a concentration lower than reported for D. magna or the marine species tested. Despite this other studies on C.dubia (England, 1995) determined a higher NOEC of 0.1mg/l for this species.

An additional study is being carried out during 2020/21 to investigate the toxicity of nonylphenol on the pacific oyster Crassostrea gigas. This study is investigating long term, reproductive and transgenerational effects.