Cigarette butts are the most common type of litter found in marine environments and an estimated 4.95 trillion are discarded outside every year. New research just published in the journal Tobacco Control shows that cigarette butts leach metals into the ocean, representing a serious form of environmental contamination.
In 2015, scientists tested nine locations along the coast of the Persian Gulf throughout the summer. They tested water samples for cadmium, iron, arsenic, nickel, copper, zinc, and manganese. Samples were taken 10 days apart in order to check for changes in concentration. The researchers detected significant levels of all seven metals. The concentrations stayed stable even during different sampling times, showing that ocean currents and other factors didn’t affect the level of contamination. The researchers also tested individual cigarette butts and found that the concentrations of metals varied in each one. For example, the level of arsenic found in cigarette butts ranged from 0.12 μg/g to 0.48 μg/g. The authors believe that cellulose acetate, used to make cigarette filters, may be helping the transfer of these metals into the water. Another source of metal contamination is from the growth and preparation of tobacco plants, explaining why individual cigarette butts may contain different metal concentrations.
The researchers concluded that large amounts of toxic metals are leaching into the ocean from littered cigarette butts. Cadmium, iron, arsenic, nickel, copper, zinc, and manganese were all found in significant concentrations along the Persian Gulf coast. These metals can be harmful to wildlife, including fish and invertebrates. While there has been some past research showing the negative effects of heavy metals on some species, more research is needed to fully investigate the impacts of leached metals. The researchers hope that their findings will prompt further studies on both metal concentrations in the ocean and the general behavior of leached metals from cigarette butts. Cigarette butts are a major form of litter in marine environments so it’s important that we fully understand how they affect local ecosystems.
Sina Dobaradaran et al. Association of metals (Cd, Fe, As, Ni, Cu, Zn and MN) with cigarette butts in northern part of the Persian Gulf. Tobacco Control (2016).