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Factor analysis suggested vehicular emissions inclusive of petrol- and diesel-driven engines as probable sources.

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Geochemical fractionation of iron (Fe), manganese (Mn), copper (Cu), chromium (Cr), lead (Pb), zinc (Zn), and nickel (Ni) were determined using five-stage sequential extraction in sediments collected from estuarine stretches of Cauvery River delta on the eastern coast of India with emphasis on seasonal variation. Abundance of metals in terms of sum of total fractionations varied in the following order: Fe > Mn > Cr > Zn > Cu > Ni > Pb. Exchangeable fraction, believed to be bioavailable, showed differential abundances during the dry and wet seasons in the following order: Pb > Zn > Cu > Mn > Ni > Cr > Fe and Zn > Cu > Cr > Ni > Mn > Pb > Fe, respectively, indicating the possibility of anthropogenic influence. Among nonlithogenic fraction, organic matter-bound fraction is the second largest and a key scavenger for all of the heavy metals studied except Fe and Mn. A significant portion of Cu-associated organic matter fraction shows strong association of Cu with organic matter at most of the sampling sites. Environmental risk of metals evaluated using risk-assessment code and mobility factor showed low to high risk for Pb, Zn, and Cu. The results of the present study also hint at notable enrichment of heavy metals in the certain pockets of the Cauvery Estuary.

This study investigates the composition and potential larvicidal activity of the essential oils isolated from the elite plant, Artemisia vulgaris L. which is commonly known as mugwort. Essential oils were hydrodistilled from in vitro raised stems and analysed by GC-MS. The major components of this oil were camphor, camphene, α-thujone, 1,8-cineole, γ-muurolene and β-caryophyllene. Mosquito larvicidal assays were carried out to test the efficacy of the oil against the dengue vector, Aedes aegypti. Laboratory reared third instar larvae were exposed to different concentrations of the oil solution and activity was assessed at different exposure times according to standard WHO procedure. Results showed that 100% larval mortality was achieved when the larvae were treated with 500 ppm oil solution with an exposure time of 8 h. The present study has shown that mugwort oil is a potential larvicide against Aedes aegypti even in low doses of the test solution. The results indicate that the natural insecticides could be used in the place of synthetic insecticides and save our environment from chemical hazards.