Calcium dipropionate

Short-term toxicity to aquatic invertebrates

Description of key information

Neonates (< 24 h) of Ceriodaphnia dubia and Daphnia magna were exposed to calcium in form of CaCl2, CaSO4 and a mixture thereof (3.8/1; v/v). For C. dubia, the 48 h - EC50 (mobility) values of 660.2, >561.7 and 988.3 mg Ca/L, respectively, were far above the OECD test limit of 100 mg/L. For D. magna, the 48 h - EC50 (mobility) values correspond to 999.3, >579.4 and 955.9 mg Ca/L, respectively (Mount 1997), and are also above the OECD test limit. In European stream water, the median background concentration of calcium amounts to 40 mg Ca/L (Salminen et al. 2005). Since calcium is an important macronutrient for invertebrates, all aquatic test media contain calcium (added in form of salts such as calcium sulfate) moreover calcium contributes to the required water hardness. The acute toxicity test with D. magna according to OECD 202 uses Elendt medium and reconstituted water (ISO 6341-1982), which contain 293.8 mg CaCl2*2 H2O/L (corresponding to 80 mg Ca/L) and the water hardness should range from 140 to 250 mg CaCO3/L (corresponding to 56 – 100 mg Ca/L).

Pillard et al. 2000 investigated the effect of calcium chloride (CaCl2) on saltwater species Mysidopsis bahia and determined a 48 h - LC50 of 1100 mg Ca/L. An acute 96 h - LC50 of 158 mg Ca(OH)2/L (nominal) to sand shrimp Crangon septemspinosa was reported by Locke et al. 2009. However, the latter LC50 should be evaluated with caution since a steep pH increase (pH at LC50 = 9.70) and not the calcium ions may have been responsible for the observed effect. Calcium concentrations (~ 400 mg Ca/L, Sverdrup et al. 1942) of natural sea water are typically above the LC50 -value from Locke et al. 2009, indicating that the observed mortality was not due to elevated calcium concentrations.

 

In sum, calcium as an essential element has a very low potential for acute toxicity to freshwater and saltwater invertebrates.