Observed and predicted reproduction of Ceriodaphnia dubia exposed to chloride, sulfate, and bicarbonate

Abstract

Chronic toxicities of Cl(-), SO(4) (2-), and HCO(3) (-) to Ceriodaphnia dubia were evaluated in low- and moderate-hardness waters using a three-brood reproduction test method. Toxicity tests of anion mixtures were used to determine interaction effects and to produce models predicting C. dubia reproduction. Effluents diluted with low- and moderate-hardness waters were tested with animals acclimated to low- and moderate-hardness conditions to evaluate the models and to assess the effects of hardness and acclimation. Sulfate was significantly less toxic than Cl(-) and HCO(3) (-) in both types of water. Chloride and HCO(3) (-) toxicities were similar in low-hardness water, but HCO(3) (-) was the most toxic in moderate-hardness water. Low acute-to-chronic ratios indicate that toxicities of these anions will decrease quickly with dilution. Hardness significantly reduced Cl(-) and SO(4) (2-) toxicity but had little effect on HCO(3) (-). Chloride toxicity decreased with an increase in Na(+) concentration, and HCO(3) (-) toxicity may have been reduced by the dissolved organic carbon in effluent. Multivariate models using measured anion concentrations in effluents with low to moderate hardness levels provided fairly accurate predictions of reproduction. Determinations of toxicity for several effluents differed significantly depending on the hardness of the dilution water and the hardness of the water used to culture test animals. These results can be used to predict the contribution of elevated anion concentrations to the chronic toxicity of effluents; to identify effluents that are toxic due to contaminants other than Cl(-), SO(4) (2-), and HCO(3) (-); and to provide a basis for chemical substitutions in manufacturing processes.

The Effects of Elevated Specific Conductivity on the Chronic Toxicity of Mining Influenced Streams Using Ceriodaphnia dubia

“…Results of the 129 toxicity tests described herein are consistent with available literature concerning toxicity of sulfate-dominated mining effluents [34], simulated mining effluents [35] and sulfate toxicity [19, 20]. Kunz and others [36] reported the chronic toxicity of reconstituted waters simulating alkaline mine discharges to C .…”

“…The ability of hardness to mitigate toxicity was reduced in the 320 mg/l CaCO3 treatment of the study with NOEC/LOECs for sulfate exposure lower at the highest hardness concentration. Lasier and Hardin [20] reported NOEC/LOEC concentration values of 1000/1250 mg/l sulfate in water with moderate-hardness and moderate alkalinity. In testing of a saline mine discharge with the cladoceran, Moinodapnia macleayi , van Dam and others [37] found reproductive impairment evident at 1500 μS/cm in a sodium sulfate test solution.…”

“…There is also much evidence that the presence of two or more ions can ameliorate toxicity and result in lower toxicity levels than expected by individual ions [14, 16, 17, 18]. In particular, hardness is known to mitigate sulfate and chloride toxicity [16, 17, 19], but does not affect the toxicity of the bicarbonate ion [20]. The chronic toxicity of complex salt mixtures is also well studied and the acute to chronic ratios of salts are relatively low [12, 20, 21].…”

“…In particular, hardness is known to mitigate sulfate and chloride toxicity [16, 17, 19], but does not affect the toxicity of the bicarbonate ion [20]. The chronic toxicity of complex salt mixtures is also well studied and the acute to chronic ratios of salts are relatively low [12, 20, 21]. …”

Chronic toxicity of major ion salts and their mixtures toCeriodaphnia dubia

“…Generally speaking, EC50/IC50 values from these studies were within or only marginally beyond the intertest variability observed in the present study at 0.36 mM Ca. Lasier and Hardin (2010) tested the toxicity of NaCl, Na 2 SO 4 , and NaHCO 3 in each of 3 dilution waters with varying Ca and alkalinity. Lasier and Hardin (2010) tested the toxicity of NaCl, Na 2 SO 4 , and NaHCO 3 in each of 3 dilution waters with varying Ca and alkalinity.…”