A cigarette contains around 4,000 substances, 250 of which are harmful to health and 50 of which are carcinogenic. A single cigarette butt can pollute up to 500 litres of water. Many of these substances accumulate in the filter. As well as nicotine, butts therefore contain traces of toxic products (pesticides, phenols, ammonia, cadmium, arsenic, mercury, lead, etc.) that are diluted in water or spread in the soil, which they contaminate.
The filter is not biodegradable.
The filters are made of cellulose acetate, a plastic material which, when exposed to ultraviolet rays, breaks down into thousands of micro-plastic particles. They take up to 15 years to degrade, depending on the environmental conditions, i.e. the quality of the soil and the weather.
See our infographic "The life of a cigarette butt" available here