Amoxicillin

Short-term toxicity to fish

Description of key information

Weight of evidence: Test method OECD 203. No GLP. The LC50 (96h) was determined to be > 1000 mg/L based on mortality (nominal concentration).
Weight of evidence: Test method OECD 203. No GLP. The LC50 (96h) to zebrafish was determined to be > 100 mg/L based on mortality (nominal concentration). 
Weight of evidence: Test method OECD 236 (draft). No GLP. The test item provoked premature hatching of embryos (48h-EC50 = 132.4 mg/L; nominal concentration).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1 000 mg/L

Additional information

A short-term toxicity study to fish was performed by Park et al. (2008) according to OECD Guideline 203. Five Oryzias latipes juveniles (10-14 days) per dose and replicate (4 replicates) were exposed up to 1000 mg/L amoxicillin for 96 hours under semi-static conditions (test solution was changed after 48 hours). There is no data on analytical monitoring. The LC50 (96 h) was determined to be > 1000 mg/L based on mortality.

Oliveira et al. (2003) analysed the acute toxicity of amoxicillin in a Fish Embryo Acute Toxicity (FET) Test (Draft OECD Guideline 236) and in a Fish, Acute Toxicity Test (OECD Guideline 203). In the first one, zebrafish eggs were collected within 30 min after natural mating and exposed to 0, 75, 128, 221, 380, 654 and 1125 mg/L of amoxicillin. Ten eggs per treatment were distributed in 24-wells microplates in triplicate for 96 hours. The LC50 could not be determined since no mortality was observed (96h-LC > 1125 mg/L). The test item provoked premature hatching of embryos (48h-EC50 = 132.4 mg/L). The most frequent malformations due to amoxicillin exposure were oedemas and tail deformities. In the second study, 12 fish were divided in 3 replicates and exposed to 0, 11, 10, 25, 50 and 100 mg/L for 96 hours. No mortality was observed and the 96h-LC50 was determined to be > 100 mg/L. No data on analytics was reported in both tests. In the both studies the basal activities of enzymatic biomarkers were assessed (no guideline was followed). Tissues of adults and pools of embryos were used of catalase, glutathione-Stransferases and lactate dehydrogenase determinations. Amoxicillin inhibited catalase and induced glutathione-S-transferases in zebrafish adults. According to the authors, short-term effects were observed only at high doses indicating that physiological impairment in fish populations in unlikely to occur.