Abstrato

Seawater quality and trends in heavy metal distribution in marine sediment along Alang Sosiya Ship Breaking Yard (ASSBY) region

H.J.Jani, Shriji Kurup, Ratna Trivedi, P.M.Chatrabhuji, P.N.Bhatt

Alang-Sosiya Ship Breaking Yard (ASSBY), is situated at 21°5Â’ 21°29Â’ north and 72° 5Â’ 72° 15Â’ east on the western Coast of Gulf of Cambay. The sheltered coast here is conducive for forced ship beaching due to suitable tidal amplitude and beach profile, including the availability of around 40,000 workersmakes it the largest ship breaking site in the world.[1] The type of ships dismantled includes General Cargo&Bulk carriers; Oil tankers Passenger; Cruisers; Drill Ships et. Since, its inception in 1982, ASSBY has so far recycled 35.61 million of light displacement tonnage (LDT).[2] Ship breaking activity generates hazardous waste like heavy metals which find their way into the marine water and sediment. The present study is to understand the seawater quality and trends in heavy metal distribution in the marine sediments including the net effect over the Gulf of Khambhat region. Samples were analyzed from seawater and sediment samples taken from high tidal, low tidal and offshore region. The samplings were also conducted during pre-monsoon and post-monsoon to analyze the seasonal trends. The paper focuses on the heavy metal distribution in sediment samples over the high tidal, low tidal and offshore region along ASSBY. The results reveal distinct areas of abundance of heavy metals especially along the Alang area.. They study concludes that the high deposition rates in the Gulf of Khambhat, the tidal amplitude and currents and shoreline morphology and the influence of coastal processes overall influences the distribution of heavymetal including a shielding or de-shielding effect due to the sedimentation pattern. The correlations between the coastal process operating in the Gulf (like tides, currents, sedimentation and suspended sediment transport and deposition etc.) with the physico-chemical properties of the marine waters and sediments, the pollutants, as well as the geomorphology of the coastal shorelines, intertidal and offshore regions needs to clearly modeled to control the spread of the pollutants, estimate the net impacts and find solutions for the sustainable development of the coastal areas of the Gulf of Khambhat including ASSBY. The overall metal concentrations are higher than permissible levels and there is a need to move towards cleaner ship breaking or recycling technologies and process.