Adsorption and desorption of 3,4-dichloroaniline on soil.

Adsorption and desorption experiments on 3,4-dichloroaniline (DCA) using three samples of soil or sediment showed that the compound adsorbed very fast and then remained quite stable bound to the soil. The reaction partner is most probably the organic part of the soil. Reactions between the amino group of DCA and oxygen or carbon of oxygen-containing groups lead to strongly bound and stable products

Characterization of Humic Substances by ESR Spectroscopy.

Humic substances in aqueous solution undergo characteristics alterations when irradiated with light of wavelengths >290 nm. Humic substances subjected to a preliminary irradiation are less capable of generating reactive oxygen species. This effect is illustrated by changes in spectroscopic (u.v., ESR) and other physical properties of the samples

Photoreaction of salicylic acid in aquatic systems.

Photoreactions of salicylic acid and Na-salicylate in aquatic systems were investigated. Humic acid-like polymers, CO2 and singlet oxygen were identified as irradiation products. Reactivity was increased in the presence of green algae

Photochemical aging of humic substances.

Humic substances in aqueous solution undergo characteristic alterations when irradiated with light of wavelengths >290 nm. Humic substances subjected to a preliminary irradiation are less capable of generating reactive oxygen species; this indicates a decrease in photoreactivity. This effect is accompanied by changes in spectroscopic (UV, ESR) and other physical properties of the samples

Toxicity of Lindane to Freshwater Insect Larvae in Compartments of an Experimental Pond.

The acute and chronic toxicities of lindane to larvae of the freshwater insects Chironomus riparius Meigen, Chaoborus flavicans (Meigen), and Sigara striata (L.) were investigated in mesocosm compartments of an experimental pond. The following median lethal concentrations (LC50s) were determined: 240-hr LC50 of 2.0 μg lindane liter−1 for second instar C. riparius, 72-hr LC50 of 6.5 μg lindane liter−1 for fourth instar C. riparius, and 96-hr LC50s of 4.0 and 3.9 μg lindane liter−1 for fourth instar C. flavicans and fourth or fifth instar S. striata, respectively. Lindane significantly reduced the growth over 10 days of second instar C. riparius compared to that of the control at the treatment concentrations where larvae survived (1.0, 2.5, and 7.0 μg lindane liter−1). A significant increase in the median emergence time in comparison to that of the control was observed for C. riparius exposed to 0.8 and 2.0 μg lindane liter−1, with higher concentrations causing 100% mortality. The findings compare well with previously reported laboratory data on the toxicity of lindane to insects and support the methodology and results of a laboratory growth test for C. riparius