table below was created. Discarded cigarette filters usually end up in the water system through drainage ditches and are transported by rivers and other waterways to the ocean. Aquatic life health concerns In the 2006 International Coastal Cleanup, cigarettes and cigarette butts constituted 24.7% of the total collected pieces of garbage, over twice as many as any other category, which is not surprising seeing the numbers in the table above of waste produced each year. Cigarette filters contain the chemicals filtered from cigarettes and can leach into waterways and water supplies. The toxicity of used cigarette filters depends on the specific tobacco blend and additives used by the cigarette companies. After a cigarette is smoked, the filter retains some of the chemicals, and some of which are considered carcinogenic. When studying the environmental effects of cigarette filters, the various chemicals that can be found in cigarette filters are not studied individually, due to its complexity. Researchers instead focus on the whole cigarette filter and its LD50. LD50 is defined as the lethal dose that kills 50% of a sample population. This allows for a simpler study of the toxicity of cigarettes filters. One recent study has looked at the toxicity of smoked cigarette filters (smoked filter + tobacco), smoked cigarette filters (no tobacco), and unsmoked cigarette filters (no tobacco). The results of the study showed that for the LD50of both marine topsmelt (Atherinops affinis) and freshwater fathead minnow (Pimephales promelas), smoked cigarette filters + tobacco are more toxic than smoked cigarette filters, but both are severely more toxic than unsmoked cigarette filters. Other health concerns Toxic chemicals are not the only human health concern to take into considerations; the others are cellulose acetate and carbon particles that are breathed in while smoking. These particles are suspected of causing lung damage. The next health concern is that of plants. Under certain growing conditions, plants on average grow taller and have longer roots than those exposed to cigarette filters in the soil. A connection exists between cigarette filters introduced to soil and the depletion of some soil nutrients over time. Another health concern to the environment is not only the toxic carcinogens that are harmful to the wildlife, but also the filters themselves pose an ingestion risk to wildlife that may presume filter litter as food. The last major health concern to make note of for marine life is the toxicity that