Matter added to plastic can be extremely harmful to the environment and health when these substances leak out of the plastic and then end up either in the environment or in the food chain. This problem is associated with daily use of plastic. Additives that leak into the sea from plastic are immediately diluted by seawater, which means that concentrations are no longer measurable. The leakage of these chemicals play no significant role in the sea. By contrast, see as an example this US report from April 2009.
The most famous and controversial is bisphenol A (BPA). BPA is found in many types of plastic including the packaging of plastic bottles. It is a virtually unbreakable plastic that is easy to clean. BPA may leak under conditions (damage or heating) and contaminate food. The substance behaves as a hormone, especially as the female hormone estrogen. Even small amounts would have harmful effects. An example of the effect of this is the early onset of puberty found in many children today. In Europe, a ban on the sale of baby bottles containing bisphenol A will apply from June 2011.
Despite the objections, BPA is still widely used in plastic products. Most of the BPA production is for making polycarbonate, a hard and transparent plastic that is recognized by recycle code #7.
Phthalates are used as plasticizers for plastic, especially in polyvinyl chloride (PVC). Due to the fact that phthalate molecules move between the polymer chains that plastics are comprised of, over time some of the plasticizers escape and leak into the environment. The phthalates do not completely break down. They can accumulate in small organisms and end up in the food chain as well. Research provides evidence that phthalate worms disrupt human and animal hormone and have carcinogenic properties.
Plastic is made of petroleum and would make it highly flammable. To prevent plastic from burning too easily, fire or flame retardants are added. Plastics use a lot of organobromium compounds such as PBBs (polybromobiphenyls) and PBDOs (polybroom-diphenyloxides). The retardants are incorporated into the following types of plastic:
- polystyrene (PS),
- polyurethane (PUR),
- polyvinylcholoride (PVC) and
- polypropylene (PP).
These plastics find their application in all kinds of electronics, insulation materials, tubes, and so forth. The substances are poisonous and do not break down easily. During combustion, fire retardants form toxic dioxins.
From MF plastic (melamine-formaldehyde) formaldehyde can be released. Also in some plastic bottles and packaging plastics, formaldehyde is used. The substance is classified as carcinogenic. Exposure to the substance may cause irritated eyes, nose, throat or skin. Some people have an allergy to formaldehyde.