Plastics pose a threat to the environment because the breakdown of different types of plastic leads to the release of various toxic chemicals. Plastic debris prior to decomposition also poses a variety of risks to wildlife and ecosystems.
Chemist Katsuhiko Saido of Nihon University in Japan led a team of researchers to discover that plastic breaks down quickly in the ocean, releasing chemicals such as bisphenol A, or BPA, and styrene trimer. Styrene trimer is potentially carcinogenic, while BPA interferes with animal endocrine systems, disrupting reproductive function. This same breakdown may also occur in landfills where chemicals potentially leech into groundwater supplies. According to the Centers for Disease Control and Prevention, 93 percent of people exhibit discernible levels of bisphenol A in urine. In the world's waterways, these toxins extend beyond the water's surface. Many of these toxic molecules are heavier than water, meaning they slowly sink and disperse throughout the water column. Warm, tropical waters are more susceptible to this breakdown, as breakdown occurs more quickly in warmer temperatures.
Aside from chemical byproducts, intact plastics pose an environmental threat. Many animals accidentally ingest plastic products, sometimes with fatal results. Plastic bags and soda rings also entangle unlucky wildlife, sometimes preventing the mouth from opening or causing suffocation. Invasive species may also hitch rides on floating plastic debris in water.