Bio-monitoring of persistent organochlorines in human milk and blood samples from sub-Himalayan region of India.

In the present study, concentrations of organochlorine pesticide residues viz. Dichlorodiphenyltrichloroethane and its metabolites (DDTs) and Hexachlorocyclohexane isomers (HCHs) in human breast milk and human blood samples, collected from several high altitude regions of Garhwal Himalaya in Uttarakhand, India viz. Devprayag, Chamoli, Uttarkashi, Joshimath, Bhatwari and Gangnani (altitude ranging from 472 to 1,982 m above sea level) were determined. Mean concentrations of HCH and DDT in human milk samples ranged from 4.53 to 34.32 mg/kg and 6.09 to 12.98 mg/kg, respectively. While the human blood showed mean values ranging from 6.64 to 281.7 µg/L and 12.37 to 104.10 µg/L for HCH and DDT, respectively. The study showed much higher concentrations of organochlorine residue contamination in the Garhwal region as compared to other parts of India. Risk assessments for infants were also calculated and were found within WHO limits.

Insecticidal activity of Valeriana jatamansi (Valerianaceae) against mosquitoes.

A root extract of Valeriana jatamansi (code BAL-O) exhibited larvicidal and adulticidal activity against different mosquito species. The median lethal concentration (LC50) of BAL-O against larvae of Anopheles stephensi, Anopheles culicifacies, Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus were 68.1, 42.8, 51.2, 53.8, and 80.6 mg/liter, respectively. The LC50 and the 90% lethal concentration against adult An. stephensi, An. culicifacies, Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus were 0.14, 0.16, 0.09, 0.08, and 0.17 and 0.24, 0.34, 0.25, 0.21, and 0.28 mg/cm2, respectively. The median knock-down time and 90% knock-down time of the fraction were 13, 13, 12, 13, and 18 and 24, 25, 21, 20, and 42 min against An. stephensi, An. culicifacies, Ae. aegypti, An. albopictus and Cx. quinquefasciatus, respectively, using 0.28 mg/cm2 impregnated papers. The median effective time and 90% effective time against An. stephensi at 4 degrees C were 46.6 and 8.7 days, and at 29 degrees C, 25.5 and 5.6 days, respectively. Gas chromatographic-mass spectrometric analysis of BAL-O showed 2-butanone,4-(2,6,6-trimethyl-2-cyclohexen-l-yl) (10.11%), patchouli alcohol (8.55%), cubenol (5.97%), caryophyllene oxide (5.46%), cadinol (5.23%), and aristolene (5.19%).

Larvivorous activity of Poecilia reticulata against Culex quinquefasciatus larvae in a polluted water drain in Hardwar, India.

The efficacy of the larvivorous fish Poecilia reticulata against mosquito larvae was monitored in a drain at Bharat Heavy Electricals Limited, Hardwar, India. The water was polluted and the water flow was in some way impeded. Poecilia reticulata failed to feed on Culex quinquefasciatus larvae in this drain. Laboratory experiments also confirmed the inefficacy of P. reticulata as a predator of Cx. quinquefasciatus larvae during the first 24 h. Significant differences in the efficacy of P. reticulata against Cx. quinquefasciatus were recorded between polluted water and drinking water. Poecilia reticulata preferred to feed on other available food present in the polluted water rather than on Cx. quinquefasciatus larvae. This was verified by the identification of plankton in the gut content of the fish and by the high density of plankton present in the polluted water.