Assessment of petroleum hydrocarbon (PHC) in the Chilika Lagoon, India, revealed a significant spatio-temporal variation in surface water (analysis of variance: n = 120, p < .01), whereas insignificant variation in sediment samples. The lagoon exhibited the highest PHC concentration during summer, attributed to higher boat activity and mixing of PHC from bottom sediment. For PHC in both the water of the lagoon and regions adjacent to jetties, the northern sector exhibited highest concentrations, followed by the southern, outer channels and central sectors, in order. The highest PHC level was due to the highest density of fishing boat operations and maintenance activities, as well as the resuspension of lake sediments across the shallowest region of the lagoon. The PHC found in the water and sediment in the jetty regions were relatively high in comparison to the rest of the lagoon, again attributed to the maintenance and operational activities of the motorised boats in the jetties. The sediment PHC concentration was ∼1000 times higher than the respective value for water, which could result from long-term deposition. The overall PHC concentration in the lagoon and jetties was found to be under the threshold limit and hence there is no risk to the existing biodiversity of the Chilika Lagoon. ARTICLE HISTORY

In this review paper the present status of coastal lagoon and future challenges which will be faced by the coastal lagoon is discussed. Coastal lagoon provides great livelihood for a larger portion of human population through fisheries and tourism point of view thus crucial in socio economic aspect. Due to natural and anthropogenic activity, stress on coastal lagoon is increasing day by day. Thus steps should be taken for regular monitoring and planning for better management is found to be imperative in regards to present day situation

The kinetics of oxidation of dimethyl, dipropyl, and diphenyl sulfides by pyridinium chloro chromate in chlorohenzene-nitrobenzene mixtures are reported. The rate data show Michaelis-Menten behavior. The oxidation process is catalyzed by the organic acids like dichloro and trichloro acetic acids. The rate-determining step appears to be a unimolecular decomposition of a complex of the reactants.

Pyridiniumchlorochromate (PCC) oxidizes aniline and substituted anilines except nitro anilines smoothly in chlorobenzene-nitrobenzene mixtures in the presence of dichloroacetic acid. The reaction has unit dependence on each of the aniline, PCC, and dichloroacetic acid concentrations. Electron-releasing substituents accelerate the reaction, whereas electronwithdrawing groups retard the reaction, and the rate data obey Hammett's relationship. The reaction constant p is -3.75. Azobenzene and p-benzoquinone have been obtained as products. The observed experimental data have been rationalized in terms of the formation of an intermediate complex involving PCC-amine undergoing a rapid decomposition to products.

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