To assess the damage caused by pesticides and their mixtures on humans, we designed in-vitro experiments to evaluate their cytotoxicity and genotoxicity. Three equimolar pesticide mixtures were investigated for their capability to affect cultured human peripheral blood lymphocytes. The LC50 values for cytotoxicity, using standard trypan blue dye exclusion and calculated by probit analysis, were 4.18, 5.76, and 7.5 microM for endosulfan, carbofuran, and monocrotophos, respectively. When combined in equimolar concentrations, the LC50 values for cytotoxicity were 0.7, 0.9, and 1.0 microM for monocrotophos + carbofuran, endosulfan + monocrotophos, and endosulfan + carbofuran, respectively, using the method. DNA damage was estimated using chromosomal aberrations (chromatid breaks, fragments, gaps, aneuploidy, and satellite association) and comet assays using 1/10 of the LC50 concentrations. Using a standard alkaline comet assay procedure, high concentrations of individual pesticides (0.5-4.0 microM) caused significant DNA damage as indicated by visible tail lengths. Lower concentrations (0.05-0.5 microM) of their binary mixtures could cause the same effect. The results suggest that analysis of genotoxicity may serve as an important biomarker for occupational and household exposure to pesticides, especially mixtures of pesticides, with different modes of action.

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An experiment was carried out to study the effect of phosphorus and zinc on yield, phosphorus and zinc content in rice as well as P distribution in post harvest soil, on a silty loam soil of Sonatola series (Non-calcareous Dark Grey Floodplain Soil) at Bangladesh Agricultural University Farm. There were 3 levels of P (0, 25 and 50 kg ha-I from TSP) and 4 levels of Zn (0,5,10 and 20kg Zn ha-1 from zinc sulphate) along with basal doses of 100 kg N ha-1 from urea, 40 kg K20 ha-1 from mediate of potash and 12 kg S ha-1 from gypsum. The single and interaction effect of P and Zn had significant positive effect on the grain and straw yield. The highest grain yield (5.97 t ha-l) and straw yield (11.50 t ha-1) were obtained from Zn10 P50 treatment. Phosphorus application significantly increased the P content in grain and straw but zinc content significantly decreased while effect of zinc significantly decreased the P content in grain and straw but increased the Zn content. The highest amount of P content in grain and straw were 0.35% and 0.140% respectively obtained from Zn0 P50 treatment whereas the zinc content in grain and straw were 32.8 ppm and 50.60 ppm respectively obtained from Zn20 P0 treatment. The availability of phosphorus gradually increased with the increasing levels of P and decreased with the increasing levels of Zn. The maximum water-soluble P (4.5mgkg-1) and labile P (1.8 mgkg-I) were obtained from Zn0 P50 treatment. The application of P and Zn gradually increased the Al-Fe-P, Mg/Ca-P and Total P with the increasing levels of P and Zn. The highest amount of Al/Fe-P, Mg/Ca­P and Total-P were obtained from Zn20 and P50 treatment. The combined application of P and Zn increased the grain and straw yield but decreased P and Zn content and availability of P to from Al/Fe-P and Mg/Ca-P as a result of Zn-P interaction in soil solution.