title: The effects of CaCl2 and CaBr2 on the reproduction of Daphnia magna Straus.
abstract: Concentrated CaCl2 and CaBr2 salt solutions of densities up to 2.3 kg L-1 are regularly used to control hydrostatic pressure in oil wells during special operations in the exploration and production of natural gas and crude oil. Various concentrations of high density salts are frequently left in mud pits near the drilling site as waste, polluting fresh and ground waters by spillage and drainage. The toxic effects of these salts have already been observed. This study investigated the effects of CaCl2 and CaBr2 on water flea Daphnia magna Straus in a 21-day reproduction test. The three tested concentrations of CaCl2 (240, 481, and 1925 mg L-1) caused a significant dose-response decrease of reproduction (p<0.001). With CaBr2 (533 and 1066 mg L-1), only aborted eggs were produced, demonstrating the embryotoxicity of the substance. The results suggest that high concentrations of the tested chemicals are harmful to Daphnia's reproduction and could reduce its abundance.
authors.forename: Neda
authors.initials: N
authors.lastname: Mažuran
authors.forename: Vladimir
authors.initials: V
authors.lastname: Hršak
authors.forename: Goran
authors.initials: G
authors.lastname: Kovačević
mesh_terms: D000818:Animals; D001965:Bromides / Q000009:adverse effects*; D002122:Calcium Chloride / Q000009:adverse effects*; D017610:Calcium Compounds / Q000009:adverse effects*; D017523:Croatia; D003621:Daphnia / Q000254:growth & development*; D004305:Dose-Response Relationship, Drug; D010063:Ovum / Q000187:drug effects*; D012098:Reproduction / Q000187:drug effects*; D012989:Soil Pollutants / Q000009:adverse effects; D013723:Teratogens / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000009:adverse effects
chemical_list: D001965:Bromides; D017610:Calcium Compounds; D012989:Soil Pollutants; D013723:Teratogens; D014874:Water Pollutants, Chemical; C113019:calcium bromide; D002122:Calcium Chloride