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The Salton Sea is a hypereutrophic, saline lake in the desert of southern California. Like many lakes, the primary productivity of the Sea is limited by phosphorus. However, unlike most lakes, the release of P from the sediments is not controlled by the reductive dissolution of Fe(III)-oxide minerals. Most of the iron in the sediments of the Salton Sea is present as Fe(II)-sulfides and silicates. Rather, the sediments are dominated by calcite which is actively precipitating due to alkalinity production via sulfate reduction reactions. We hypothesized that calcite could be an important sink for phosphorus released from the decomposing organic matter. In this work we evaluated the potential for phosphate to coprecipitate with calcite formed in simulated Salton Sea sediment pore water. At calcite precipitation levels and P concentrations typical for the Salton Sea pore water, coprecipitation of P removed 82–100% of the dissolved phosphorus. The amount of P incorporated into the calcite was independent of temperature. The results of this work indicate that the internal loading of P within the Salton Sea is being controlled by calcite precipitation. Management of external P loading should have an immediate impact on reducing algae blooms in the Salton Sea. [ABSTRACT FROM AUTHOR]

Thirteen pharmaceutical and cosmetic compounds have been surveyed along the different units of a municipal sewage treatment plant (STP) to study their fate across each step and the overall removal efficiency. The STP studied corresponds to a population of approximately 100,000 inhabitants located in Galicia (northwest Spain), including three main sections: pre-treatment (coarse and fine screening, grit and fat removal); primary treatment (sedimentation tanks); and secondary treatment (conventional activated sludge). Among all the substances considered (galaxolide, tonalide, carbamazepine, diazepam, diclofenac, ibuprofen, naproxen, estrone, estradiol, ethinylestradiol, roxitromycin, sulfamethoxazole and iopromide), only significant concentrations were found for two musks (galaxolide and tonalide), two antiphlogistics ibuprofen and naproxen), two natural estrogens (estrone, estradiol), one antibiotic (sulfamethoxazole) and the X-ray contrast media (iopromide), being the other compounds below the quantification level. In the primary treatment, only the fragrances were partly removed, with efficiencies of 20-50% for galaxolide and tonalide. However, the aerobic treatment caused an important reduction in all compounds detected, between 35 and 75%, with the exception of iopromide. The overall removal efficiency of the STP ranged between 70 and 90% for the fragrances, 45 and 70% for the acidic compounds, around 67% for estradiol and 57% for the antibiotic sulfamethoxazole. [ABSTRACT FROM AUTHOR]

Abstract: Adsorption isotherms were determined experimentally for Cd(II) adsorption from aqueous solution onto natural and oxidized corncob in a batch adsorber. The adsorption capacity of natural corncob was increased 10.8 and 3.8 times when the corncob was oxidized with citric acid (CA) and nitric acid (NA), respectively. The Cd(II) ions were adsorbed mainly to the carboxylic sites since the adsorption capacity increased directly proportionally to the concentration of carboxylic sites in the corncob. The effect of the solution pH in the adsorption isotherm on natural and corncob modified with CA was assessed and it was observed that the adsorption capacity of Cd(II) on corncob depends considerably on the solution pH; Cd(II) was not adsorbed at pH less than 2 and the adsorption capacity was increased five times while the solution pH increased from 3 to 6. The adsorption of Cd(II) on corncob was reversible and the Cd(II) desorbed almost completely while reducing solution pH from 6 to 2. The adsorption capacity of natural and modified corncob was increased slightly by augmenting the temperature. By performing mass balances of ions, it was corroborated that the adsorption is mainly due to ion exchange. [Copyright &y& Elsevier]