p-(1,1-dimethylpropyl)phenol

Short-term toxicity to aquatic invertebrates

Description of key information

Davoren and Fogarty (2005), provides a 48-hr LC50 of 2.7 mg/L for Daphnia magna.  McLesse et al. (1981) provided a 96hr LC50 of 1.7 mg/L, based on mortality, with the marine invertebrate, the shrimp, Crangon septemspinosa.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.7 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

1.7 mg/L

Additional information

Reliable (Klimisch 1 or 2) short-term toxicity studies with invertebrates have been conducted for p-tert-amylphenol and are included in this dossier.

Davoren and Fogarty (2005) conducted a reliable (Klimisch 2) study according to British Standard Guideline (BS EN ISO 6341, 1996) with sodium p-tert-amylphenol with multiple species. Data obtained from tests using the salt is assumed to be representative of the parent substance due to its weak acid properties. Daphnia magna, <24 hrs old, were exposed to nominal concentrations (0.5 – 5.0 mg/L) of the test substance for 48-hrs. The 48-hr EC50, based on immobilization, for D. magna was 2.7 mg/L. Additionally, Thamnocephalus platyurus, fairy shrimp, larvae were exposed to the test substance following test guidelines presented in the Thamnotoxkit F (Alcontrol Laboratories, England). The 24-hr LC50 was 2.1 mg/L, based on mortality.

Wang et al. (2005) conducted a limit test (Klimisch 3) with p-tert-amylphenol using adult Daphnia magna.  Although a preferred endpoint, such as LC50, was not presented, the study authors evaluated the stimulation of male offspring production and anti-juvenoid activity. The NOEC was determined to be >1.0 mg/L. Although this study result cannot be used in development of PNECs, it is presented in the dossier to provide weight of evidence to classification.

Gerrtisen et al. (1998) conducted a study following methods similar to OECD 202 with p-tert-amylphenol. Less than 24 hrs old Daphnia magna were exposed to the test substance for 96 hours. Although the preferred endpoint of 48hr LC50 was not obtained and organisms were fed daily during the test, the study presents a 96-hr NOEC of 1.8 mg/L based on mortality. This study result cannot be used in development of PNECs, but is presented in the dossier to provide weight of evidence to classification.

The short-term toxicity of sodium p-tert-amylphenol exposed to marine invertebrates was investigated by Daveoren and Fogarty (2005) (Klimisch 2). Data obtained from tests using the salt is assumed to be representative of the parent substance due to its weak acid properties. The invertebrate, brine shrimp (Artemia salina), was exposed to the test chemical for 24 hours following British Standard Guidelines. The 24 -hour LC50, based on mortality, was 6.5 mg/L.

The short-term toxicity of p-tert-amylphenol exposed to marine invertebrates was investigated by McLeese et al. (1981) (Klimisch 2). The marine invertebrate, shrimp (Crangon septemspinosa), was exposed to the test chemical for 96 hours. The 96 -hour LC50, based on mortality, was 1.7 mg/L.

Reliable (Klimisch 2) short-term toxicity studies with invertebrates have been conducted for p-tert-amylphenol and sodium p-tert-amylphenol and are included in this dossier. The key study, Davoren and Fogarty (2005), provides a 48-hr LC50 of 2.7 mg/L for Daphnia magna. Consequently this value will be taken as the short-term toxicity in aquatic invertebrate’s endpoint for p-tert-amylphenol.