Quantities and composition of shore debris along Clifton Beach, Karachi, Pakistan

Debris abundance and composition were investigated for the first time along the most popular beach (Clifton Beach) of Karachi, Pakistan, which is one of the most populous cities of the world. The surveys were conducted in June, July and August 2013 to estimate the number and the weight of 10 predetermined types of debris along the beach front of Karachi. The 3-month average quantities of the debris collected from the designated transects of Clifton Beach were 2216 +/- 371 counts in number and 13.71 +/- 2.15 kg in weight. The quantities of beach debris were estimated at 8865 +/- 1483 items km(-1), with a corresponding weight of 54.83 +/- 8.58 kg km(-1). In terms of number, plastic was the most abundant debris along the beach (50.5 % of the total counts), which was followed by food (7.5 %) and paper (6.6 %) while, in terms of weight, processed wood was the most abundant debris on the beach (25.5 % of the total), which was followed by plastic (19.9 %) and metal (9.8 %). Plastic items were significantly higher (p < 0.001) than any other type of debris on the beach during all the 3 months. The predetermined types of debris were also classified on the basis of their sizes. Metal, glass, paper, plastic and rubber items were largely smaller in size while styro-foam, masonry, processed wood and cloth items were mostly larger in size. The main sources of debris were restaurants, caf,s and hawkers, which served food, beverages and mild stimulants in plastic, polystyrene and aluminum foil to the beach visitors. Furthermore, the major part of floating debris from Lyari and Malir rivers were ultimately deposited along the shoreline of Karachi.