No abstract

No abstract

Studies on marine sediments are extremely important since they act as ultimate sink of anthropogenic pollutants. The present study was conducted near Mumbai city of India to understand and assess the behaviour and fluxes of trace and toxic elements in creek sediment. Seven sediment core samples were collected and analysed for trace and toxic elements such as Fe, Cu, Pb, Zn, Rb and Sr in different sections of the core using EDXRF technique. The fluxes of the elements in each section of the core were calculated using the mass sedimentation rates derived from 210Pb dating technique and the sediment density at each location. The estimated depositional fluxes of Fe, Rb and Sr in Zone-1 and Zone-3 are in the ranges of 0.4-0.5% cm(-2) yr(-1); 4-6 microg cm(-2) yr(-1) and 10-20 microg cm(-2) yr(-1) respectively, where as they were about 3-4 times higher in zone-2 for the same elements. The depositional fluxes of elements Cu (40-60 microg cm(-2) yr(-1)), Zn (35-43 microg cm(-2) yr(-1)) and Pb (6-12 microg cm(-2) yr(-1)) were also found to be higher in zone-2 compared to zone-1 and zone-3 which can be attributed to the release from the newly developed chemical zone of Thane-Belapur industrial belt.

No abstract

No abstract

No abstract

No abstract

Aedes aegypti is an important vector for Dengue and Dengue hemorrhagic fever. Considering its medical importance and its relevance as a model system, this study was undertaken to evaluate the impact of different doses of gamma radiation for three generations of A. aegypti. Two to three days old virgin males of A. aegypti were irradiated with 15 doses of gamma radiation, ranging from 1 to 50 Gy and were immediately mass mated with the same aged virgin females. Observations were made for changes on their life history traits, particularly fecundity, hatchability, adult emergence, sex ratio and longevity, for three generations. Adult males exposed 30, 35, 40, 45 and 50 Gy doses showed a significant decrease in fecundity in F0 generations. While hatchability was observed to have decreased with increasing radiation doses from 3 Gy onwards in the F1 generation, samples irradiated with 30, 35, 40, 45 and 50 Gy maintained significant decline in hatchability in their succeeding generations, F2 and F3 also. Similarly, a decline was observed in adult emergence from 3 Gy onwards in all three generations. A male favoring sex ratio distortion was observed at the doses of 35, 40, 45 and 50 Gy in all three generations. Following exposure to 4 Gy, parental males and the resultant progeny showed increased longevity by 10.56 and 8.66 days respectively. Similarly, the F1 generations of samples irradiated with 30, 35 and 40 Gy exhibited an increase in longevity by 7.16, 7.44 and 6.64 days respectively. Dose response curve for fertility among the three generations was drawn and presented. The effect of radiological exposure on the life history traits of A. aegypti varies with dose for the three generations studied. These results have potential implications in mutational studies and risk assessment and also contribute to a better understanding towards employment of the sterile insect technique in A. aegypti, plausibly paving the way to an effective mosquito genetic control program.