A comprehensive review of the sources, distribution, ecological impacts, and remediation of persistent organic pollutants in India

Abstract

Persistent organic pollutants (POPs) are organic chemicals characterized by lipophilic properties; they pose significant risks to human health and exhibit long-range transport. This systematic review presents the distribution of POPs in the Indian environment, encompassing their inter-phase dynamics, quantitative distribution in food items, and implications on human health utilizing standard metrics. Additionally, advancements in analytical methodologies and degradation processes are also outlined. After a rigorous bibliometric analysis, we screened 200 publications on legacy POPs such as DDT and HCH, industrial POPs such as PCBs and PFAS, and accidental by-products such as PCDDs/Fs, which remain significant contributors. The concentration of legacy POPs in soil has been declining over time. The synthesized data from health matrices indicate that the levels of POPs remain within allowed ranges. Disorganized waste recycling, industrial emissions, and public health management (specifically regarding DDT) are the primary sources of POPs, while regional temperature variations predominantly govern their spread. Elevated temperatures under the tropical climate of southern India, in particular, leads to the volatilization of the majority of parent chemicals or their immediate metabolites into the surrounding atmosphere. During winter, a significant decrease in temperature leads to the deposition of metabolites in soil in Northern India. In light of the lack of data, we propose establishing a comprehensive database specific to POPs and implementing region-specific monitoring programs for both legacy and emerging POPs. The development of advanced monitoring facilities can support the National Implementation Plan, ensuring environmental sustainability and protecting public health.