Chapter 1 - Occurrence, Distribution, and Fate of Emerging Persistent Organic Pollutants in the Environment

Abstract

Persistent organic pollutants (POPs) are a group of organic compounds that are resistant to natural degradation processes, bioaccumulate in food chain and in organisms, and pose severe adverse health effects. Due to its long residence time in the environment and semi-volatile nature, they are prone for long range atmospheric transport (LRAT), resulting in transboundary deposition. The Stockholm Convention on POPs, regulates these contaminants, by imposing restrictions on production and use or recommend to phase out these compounds. POPs could be classified into three groups, namely, organochlorine pesticides, industrial chemicals and unintentionally produced by-products during various industrial processes. The Stockholm Convention initially classified 12 compounds as POPs, which are generally referred to as “dirty dozen.” Subsequently, another 16 compounds, mostly industrial chemicals were added to this list. Due to advancement in instrumental analytical techniques driven by stringent regulations on chemicals, the scientific community has pointed out that several chemicals, mostly high production volume (HPV) industrial chemicals have POPs like properties, and hence they should be regulated as POPs in order to safeguard human health and environment. Some of these compounds have been introduced as substitutes to compounds already listed as POPs. Examples includes hexabromocyclododecane (HBCD), organophosphorous flame retardants, per- and polyfluroalkyl substances (PFAS; C4–C6 fluoro compounds), short chain chlorinated paraffins (SCCPs) and tetrabromobisphenol-A (TBBPA). Some of these compounds are currently under the review of “POPs review committee.” Several of these “emerging/new POPs” or “POPs like” compounds do not satisfy all the “screening criteria” of Stockholm Convention as in the case of legacy POPs. This chapter presents an overview of selected emerging/new POPs, physico-chemical properties, its occurrence in the environment, distribution pattern, and environmental fate.