ABSTRACT
Persistence of carbosul fan and carbofuran under the Egyptian normal field conditions when used for protecting Solanum tuberosum plant was studied. carbosulfan was used for foliar application but carbofuran was used as granulcs in soil against nematodes. The residue half life [RL50] values were 2.86 and 6.41 days for carbosulfan on plant leaves and in soil. respectively. As for carbofuran which was applied in soil. the RL50 value was 6.74 days in soil surface layer. The PHI for carbosulfan in tubers is more than 16 days after foliar application, but for carbofuran the PHI is about 30 days from tuber formation. Photo-decomposition study showed that carbosulfam degraded faster than carbofuran when exposed to direct sunlight or to short wave UV light, with RL50 of 8.14 and 20.38 hr in sunlight and 6.09. 89.41 hr in UV light for carbosulfan and carbofuran. respectively. The study included also the estimation of the amounts of carbofuran resulted from carbosulfan transformation under exposure to sunlight or to UV-light as major degradation product [or metabolite] for carbosulfan. The study of the biochemical effects on the composition of the tubers revealed that the two pesticide treatments attained no significant effect on total carbohydrates content or in total lipids content. A significant decrease in total nitrogen content anti consequently total crude protein was registered only after 7 days from carbosulfan application. Soluble protein content significantly decreased after 70 days from soil application with carbofuran but returned to the normal level after 7 days. The electrophoretic patterns of soluble protein extracted from tubers were also studied
Subject(s)
Carbamates/adverse effects , Carbofuran/adverse effects , Electrophoresis/methods , EnvironmentABSTRACT
The effect of chronic exposure to carbofuran (4.5 ppm in static water) for six months on the gonadal histophysiology and hypothalamo-neurohypophyseal complex was studied in Channa punctatus. Experimental observations revealed significant inhibition of gonadal development with associated degenerative abnormalities as evidenced by ovarian and testicular histology and reduced gonadosomatic index. Degenerative changes in ovary were exihibited by stage I (oogonium) and stage II (immature/non-vitellogenic) oocytes as marked by perinuclear ooplasmic lysis, clumping and dissolution resulting in disintigration of nuclear material altogether attributed to complete degeneration of such oocytes. Testicular deleterious changes included degeneration of spermatogenic elements and necrosis of interstitial cells of Leydig. Correlative histophysiological changes were also observed in the pituitary gonadotrophs and hypothalamic, nucleus pre-opticus, neurons that were smaller, inactive and less in number with associated necrosis. Corresponding to the changes in nucleus pre-opticus neurons, significant inhibition of brain monoamine oxidase enzyme activity was also recorded in treated group. These observations suggest that carbofuran even at low concentration level under long-term exposure is capable of inducing retardation of gonadal development which might have been mediated through the impairment of the hypothalamo-neurohypophyseal-gonadal axis in this species.