Effect of cooking on arsenic concentration in rice

Environmental Science and Pollution Research - This study assessed the effect of rinsing and boiling on total content of As (tAs) and of its inorganic and organic forms in different types of rice...     

Attenuation potentials of royal jelly against hydroxyurea-induced infertility through inhibiting oxidation and release of pro-inflammatory cytokines in male rats

Environmental Science and Pollution Research - Hydroxyurea (HDU), a class of antineoplastic drugs, has a powerful efficacy in the treatment of several types of malignancies. However, it has...     

Variation in the development of cadmium resistance in Daphnia magna straus; effect of temperature, nutrition, age and genotype

The extent to which responses to toxicants can be modified by the environment and genotype of Daphnia magna is important for interpreting the results from ecotoxicity tests. Variation in the development of cadmium resistance and its relevance for survivorship has been investigated in two genetically distinct clones of D. magna. Cadmium resistance was induced by pre-exposing daphnids to a sublethal concentration of a Cd/Zn mixture and thereafter cadmium tolerance was assessed in standard acute tests. The results showed that the ability to develop cadmium resistance is affected by temperature, but there is no consistent pattern for maternal nutrition. The age of the daphnids had no apparent effect on the development of cadmium resistance. Differences in the induction of cadmium resistance between clones were seen only under resource depression.     

The response of Lemna trisulca L. to cadmium

Lemna trisulca was grown, using aseptic culture techniques in a filter-sterilized medium, a portion of which was replaced regularly during experiments. L. trisulca responded to the addition of 0.64 microM Cd with a reduction in multiplication rate (MR) 2 +/- 1 days after exposure. The internal Cd content reached 1000 +/- 140 microg Cd/g (dry wt) within 2 days exposure to 0.64 microM Cd. The final yield was reduced by an average of c.8% for each day of exposure to 0.64 microM Cd in a 14 day experiment. This implies that an equilibration period should be used for short-term bioassay tests before the effect of a toxicant is determined. Pretreating L. trisulca with 0.08 or 0.32 microM Cd for 6 weeks had no significant effect on MR or Cd uptake when plants were subsequently exposed to a range of Cd concentrations or grown in a control medium. This suggests that L. trisulca does not become acclimated to elevated Cd concentrations. The MR of L. trisulca fluctuated over a period of almost 600 days and the doubling time ranged from 1.6 to 2.4 days. This produced more than a fivefold difference in final yield in experiments of 14 days duration. The reduction in MR in response to 0.32 microM Cd during this same 600 days period averaged 24% with a coefficient of variation of 38%, and varied with the MR of control cultures. Fluctuations in the intrinsic growth rate and the effect of a toxicant on L. trisulca could potentially confound the assessment of toxicity and must be carefully considered when designing test protocols for aquatic plants.     

The fate of endosulfan in aquatic ecosystems

Endosulfan, one of the major pesticides used in cotton-growing, is of environmental concern because of its toxicity to fish and its apparent persistence in the environment. This study examines the distribution and degradation pathways for endosulfan in an aquatic system and the processes by which it is removed. In the alkaline waters of the cotton region, hydrolysis is the dominant degradation process. By this mechanism alone, the expected half-lives for the alpha- and beta-endosulfan isomers were found to be 3.6 days and 1.7 days, respectively. Partitioning studies showed, however, that the major proportion of endosulfan would associate with the sediments (log Koc(alpha) 3.6 and log Koc(beta) 4.3). Field studies confirmed the presence of high concentrations in sediments. Microcosm experiments showed that loss of endosulfan was slower than predicted from hydrolysis rates. Models are presented to explain how desorption from sediment limits the loss of endosulfan from a system.