Response and effect of two plant crude extracts on mosquito larvae culex pipiens

The response and effect of two plant crude extract from dry Damsiasa [Ambrosia maritima] and Neem seeds [Azadirachta indica] were tested against the first and third instar larvae of mosquito [Culex pipiens]. The results showed that both extracts had a larvicidal effect. Neem seed extract was more toxic than Damsissa extract against both the first and third instar larvae. In addition, the young larvae [first instar] were more susceptible to Neem seeds than the old ones [third instar] as revealed from the LC[50] values, while Damsissa showed nearly the same effect against both stages. Meanwhile, treatment of Neem seed extracts resulted in prolongation of the larval period accompanied with a decrease in larval activity. Moreover, the effect of the two extracts on larval total esterase isozymes was examined. Neem extract showed an adverse effect on the third instar larvae, since only one band [E[1]] was observed and the other 4 bands disappeared at all concentrations used, as compared with untreated control larvae [E[1], E[2], E[3], E[4], and E[5]]. Meanwhile, Damaissa extract treatment of the third instar larvae showed an additional band located between E[3] and E[4], and the absence of two bands [E[2] and E[3]] after treatment with 0.5x10[4], 1x10[4] and l.5x10[4] ppm, while treatment with 0.25x10[4] ppm did not result in any changes in larval total esterase

Organochlorine pollutants level in fish from Mariut lake, Alexandria, Egypt

The residues of twenty-five organochlorine pollutants as well as three aroclors were analyzed by capillary GLC in two Tillipia fish species and Cyprinus carpio collected from Mariut Lake, Alexandria, Egypt. The studied pollutants were DDT's isomers, hexachlorocyclohexane [HCHS] isomers as well as cyclodiene compounds, mirex, methoxychlor, toxaphene and hexachlorobenzene [HCH], aroclors 1248, 1254 and 1260 in addition to nine individual PCBs congeners. Lindane dominated the alphaisomer of HCHS. P,p'-DDE dominated other DDTs analogs in all fish samples with maximum concentration 25.0 ng/g in Cyprinus carpio. Toxaphene was detected in all fish samples with a maximum level of 29.0 ng/g in Cyprinus carpio. Aroclor 1248 dominated other aroclors in all fish samples. For PCBs 153, congener dominated other congeners. The lower chlorinated biphenyls congeners occurred at lower levels except PCB 200 which was not detected