London:Littered cigarette butts may be an important source of metal contaminants leaching into the marine environment and potentially entering the food chain, revealed a research. According to a study published in the journal Tobacco Control, cigarette filters, which are made of cellulose acetate, may act like other plastics in providing a conduit to transport metals in marine environments. Cigarette butts are the most common form of litter found in the marine environment with an estimated 5 trillion or so discarded outdoors around the globe every year. Considering the estimated amount of cigarette butts littered annually (4.95 trillion), the release of metals from littered cigarette butts in the marine environment may increase the potential for acute harm to local species and may enter the food chain, revealed the study. To gain an understanding of the potential implications, levels of metals in cigarette butts were monitored at nine different locations along the northern part of the Persian Gulf in the Bushehr seaport coastal areas. The metals assessed included cadmium (Cd), iron (Fe), arsenic (As) nickel (Ni), copper (Cu), zinc (Zn) and manganese (Mn) from discarded cigarette butts in the top 10 cm of sediment and deposited at the tidal mark on the beaches. According to the study, the response of animal and plant life to metal content is highly variable. Whereas elevated concentration of heavy and trace metals in water and soils can adversely affect some species, contamination may increase the metal tolerance of other organisms. Metal content is likely to vary according to the cultivation and growth of the tobacco leaf and the application of pesticides and weed killers, stated the researchers.