Ecotoxicological Effects of an Arsenic Remediation Method on Three Freshwater Organisms—Lemna disperma, Chlorella sp. CE-35 and Ceriodaphnia cf. dubia

Rahman, M Azizur; Hogan, Donald; Duncan, Elliott; Doyle, Christopher; Rahman, Mohammad Mahmudur; Nguyen, T. V.; Lim, Richard P.; Maher, William; Naidu, R.; Krassoi, Rick; Vigneswaran, S.; Hassler, Christel

Ecotoxicological Effects of an Arsenic Remediation Method on Three Freshwater Organisms—Lemna disperma, Chlorella sp. CE-35 and Ceriodaphnia cf. dubia

2015

Chemical methods have been used for the remediation of arsenic (As)-contaminated water; however, ecological consequences of these methods have not been properly addressed. The present study evaluated the effects of the Fe-oxide-coated sand (IOCS) remediation method on As toxicity to freshwater organisms (Lemna disperma, Chlorella sp. CE-35, and Ceriodaphnia cf. dubia). The As removal efficiency by IOCS decreased substantially with time. The IOCS remediation method was less effective at suppressing the toxicity of Asⱽ than Asᴵᴵᴵ to L. disperma but was highly effective in reducing both the Asᴵᴵᴵ and Asⱽ toxicity to C. cf. dubia. The growth of Chlorella sp. was significantly higher (p < 0.05) in remediated and pre-remediated water than in controls (non-As-contaminated filtered Colo River water) for Asᴵᴵᴵ, while the opposite was observed for Asⱽ, indicating that Asⱽ is more toxic than Asᴵᴵᴵ to this microalga. Although the IOCS can efficiently remove As from contaminated water, residual As and other constituents (e.g. Fe, nitrate) in the remediated water had a significant effect on freshwater organisms.

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