Fumaric acid

Endpoint summary

Description of key information

Aquatic toxicity tests investigating the effects of fumaric acid on organisms from three trophic levels are available. Any adverse effects to the test organisms observed in studies without pH adjustment can be attributed to acidification and are therefore not relevant for hazard assessment. In test employing pH adjustment, no negative effects were observed up to the limit test concentration of 100 mg/L in all three test species, respectively. Therefore, fumaric acid is not toxic to aquatic organisms.

Additional information

Juvenile D. rerio were exposed to a single fumaric acid concentration of 100 mg/L in a semi-static 96-hour acute toxicity test according to OECD guideline 203. The test design included an untreated control. The concentration of fumaric acid was verified analytically and the mean measured concentration was 99.03 % of nominal. Due to the acidic properties of fumaric acid addition of the test substance resulted in a marked pH change (pH 4.3–5.0) which had no influence on survival of the fish at the concentration tested. The 96-hour LC₅₀ was > 100 mg fumaric acid/L (nominal concentration). The NOEC (no-observed effect concentration) was 100 mg fumaric acid/L.

The 48-hour acute toxicity of fumaric acid to Daphnia magna was determined in two semi-static tests according to OECD guideline 202. In the first experiment daphnids were exposed to fumaric acid at nominal concentrations of 0 (control), 6.25, 12.5, 25, 50 and 100 mg/L over a 48-hour period. pH ranged from 3.7 in the 100 mg/L treatment to 7.4 in the 6.25 mg/L treatment, dependent on the nominal concentration. Concentrations of fumaric acid were verified analytically at test initiation, after 24 hours in both new and old test media, and at test termination. Mean measured concentrations were 6.02, 12.15, 23.09, 47.52 and 98.90 mg/L. The 48-hour EC₅₀ was determined to be 66 mg/L (nominal) with a 95 % confidence interval of 59–73 mg/L.

In a second experiment daphnids were exposed to fumaric acid at a nominal concentration of 0 (control) and 100 mg/L over a 48-hour period. The pH of the 100 mg/L was 8.3 at the start of each exposure period. The mean measured concentration of fumaric acid was 95.95 mg/ L. The 48-hour EC₅₀ was determined to be > 100 mg/L (nominal).

Because the effects seen in the first experiment can be attributed to the pH change, the most appropriate endpoint for the assessment the toxicity of fumaric acid is the 48-hour EC₅₀ value of > 100 mg/L obtained in the study with pH adjustment.

A 48-hour acute toxicity study was conducted in accordance with US EPA ecological research series EPA-600/3-75-009. The 48-hour EC₅₀ was determined to be 212 mg/L (with a 95 % confidence interval of 204–220 mg/L; Randall and Knopp, 1980).

Two 72-hour algal inhibition experiments were conducted with fumaric acid and Pseudokirchneriella subcapitata according to OECD guideline 203. In the first experiment algae were exposed to fumaric acid at nominal concentrations of 0 (control), 0.39, 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50 and 100 mg/L over a 72-hour period. pH ranged from 3.4 in the 100 mg/L treatment to 7.5 in the 0.39 mg/L treatment depending on the nominal concentration. Concentrations of fumaric acid were verified analytically at test initiation and termination. Geometric mean measured concentrations were 0.32, 0.74, 1.48, 3.21, 6.45, 10.95, 23.84, 49.94 and 99.40 mg/L. Based on nominal exposure concentrations the 72-hour E_yC₅₀ was determined to be 37.2 mg/L, with a corresponding NOEC of 25 mg/L. The 72-hour E_rC₅₀ was determined to be 38.9 mg/L, with a corresponding NOEC of 25 mg/L.

In the second experiment algae were exposed to fumaric acid at a nominal concentration of 0 (control) and 100 mg/L over a 72-hour period. The pH of the 100 mg/L medium was 7.4 at the start of the exposure period. The mean measured concentration of fumaric acid was 89.07 mg/L. Based on the nominal exposure concentration both the 72-hour E_yC₅₀ and E_rC₅₀ were determined to be > 100 mg/L, with corresponding NOECs of 100 mg/L.

Because the effects seen in the first experiment can be attributed to the pH change, the most appropriate endpoint for the assessment of fumaric acid toxicity is the 72-hour E_rC₅₀ value of > 100 mg/L obtained in the study with pH adjustment.

Activated sludge obtained from a sewage treatment plant was exposed to concentrations of 0 (control), 7.7, 19. 47.5, 102.4 and 300 mg fumaric acid/L in a 3-hour respiration inhibition test. The test design included duplicate samples and followed OECD guideline 209. The 3-hour EC₅₀ based on respiration inhibition was > 300 mg fumaric acid/L.