Plastic also threatens the environment due to metal additives



by LORENZO CIOTTI

Plastic also threatens the environment due to metal additives

Plastic pollution can occur in various forms, including litter abandoned on land and at sea, plastic particles in water, and Friendly Floatees. A large percentage of the plastic produced each year is used only once and then thrown away.

For the United States Environmental Protection Agency in 2011, plastics made up more than 12% of municipal solid waste. In the 1960s, however, they made up less than 1%. Halogen plastics release harmful chemicals to the surrounding soil, which penetrate deeply into groundwater or other water sources.

The damage is very serious for the living species that take in this polluted water. The areas used as landfills are constantly filled with plastic waste. In these areas there are many microorganisms that accelerate the biological degradation of plastics.

As for biodegradable plastics, methane, a dangerous greenhouse gas that contributes significantly to global warming, is released as soon as they are thrown away. Some landfills are taking the initiative to install methane capture devices, which could be used for energy, but most plants have not yet adopted them.

The researchers of the study Hazardous metal additives in plastics and their environmental impacts, published on the Environment international, told: "Historically, many additives and catalysts used in plastics were based on compounds of toxic metals (and metalloids), like arsenic, cadmium, chromium (VI), and lead.

Despite subsequent restrictions, hazardous additives remain in plastics in societal circulation because of the pervasiveness of many products and the more general contamination of recycled goods. However, little is understood about their presence and impacts in the environment, with most studies focusing on the role of plastics in acquiring metals from their surroundings through, for example, adsorption.

Accordingly, this paper provides a review of the uses of hazardous, metal-based additives in plastics, the relevant European regulations that have been introduced to restrict or prohibit usage in various sectors, and the likely environmental impacts of hazardous additives once plastics are lost in nature.

Examination of the literature reveals widespread occurrence of hazardous metals in environmental plastics, with impacts ranging from contamination of the waste stream to increasing the density and settling rates of material in aquatic systems.

A potential concern from an ecotoxicological perspective is the diffusion of metals from the matrix of micro- and nanoplastics under certain physico-chemical conditions, and especially favorable here are the acidic environments encountered in the digestive tract of many animals (birds, fish, mammals) that inadvertently consume plastics.

For instance, in vitro studies have shown that the mobilization of Cd and Pb from historical microplastics can greatly exceed concentrations deemed to be safe according to migration limits specified by the current European Toy Safety Directive.

When compared with concentrations of metals typically adsorbed to plastics from the environment, the risks from pervasive, historical additives are far more significant."