Abstract
A study was conducted to assess water and soil pollution in some selected areas of the Sundarbans mangrove forest and sea beaches of Bangladesh. Water and soil sampling sites covered Satkhira, Bagerhat, Khulna, Patuakhali, Chittagong and Cox'sbazar districts. Samples were collected in summer and winter during March 2007 to November 2008 including two disasters like sudden changes of water color at the southern Bay of Bengal and SIDR in 2007. Public perceptions about water and soil pollution were also recorded from neibouring people. Water and soil samples were analysed for pH, EC, P, S, B, Ca, Mg, K, Na, Zn, Fe, Cu, Mn, Cd and Pb in addition to TDS, HCO3 and Cl from water and N and organic matter from soils. Electrical conductance recorded in descending order at Satkhira > Khulna > Bagerhat of the Sundarbans. The levels of TDS, CI, Ca, Mg, K, Fe, Mn, Cd and Pb increased in all the locations of the Sundarbans and exceeded standard limits in winter. In sea beaches, the highest amount of most of the ions were detected at Cox'sbazar in both the seasons and the lowest was observed at Potenga in summer and Kuakata in winter. Electrical conductance increased in winter in descending order at Cox'sbazar > Potenga > Kuakata of the beaches. The concentrations of P, Zn, Fe, Mn, Cu, Cd and Pb increased in summer but pH, EC, TDS, Ca, Mg, K, Na, S, Cl and B increased remarkably in winter in all the three beaches. The concentrations of S, Mn, Ca, Mg, K, Na, Cl, Cd and Pb in waters of the Sundarbans at Satkhira exceeded standard limits due to sudden changes of water color in the southern Bay of Bengal and adjacent rivers in April 2007. The S, Zn, Mn and Cd exceeded standard limits but P, S, B, Na, Zn, Cu, Mn and Pb decreased after SIDR-2007 as compared to normal condition. The soils of most of the locations in the Sundarbans and sea beaches recorded higher salinity in winter. The intensity of pollution due to ionic constituents was higher in Satkhira followed by Bagerhat and Khulna regions of the Sundarbans. Kuakata sea beach was least polluted and may be termed as virgin beach as compared to Patenga and Cox'sbazar. Public perception reflected that the agrochemicals, polythene bags, industrial and fishing wastes were responsible for beach environment pollution and shipping waste disposal, industrial waste and deforestation were responsible for pollution of the Sundarbans mangrove forest.