Banned persistent organic pollutants: a quantitative and qualitative systematic review on bats (Mammalia: Chiroptera)

Abstract

Among the several noxious characteristics of Persistent Organic Polluters (POPs) is a low environmental degradation rate, which means they remain in the environment for decades. One of the measures adopted to mitigate environmental contamination is the imposition of bans and restrictions to several chemical compounds. But are bans being efficient to reduce the amount of such chemicals in the environment? In this systematic review, we tested the efficacy of banning POPs using bats as biomonitors in terrestrial habitats. Bats provide relevant ecosystem services, are found in several anthropogenic matrices, and are highly exposed to chemical pollutants such as POPs due to their feeding and behavioral habits. We found that POP concentrations in biological bat tissues in the genus Myotis in the United States decreased over the years since they were banned. We also realized there is a scarcity of studies in neotropical regions, where the different feeding guilds of bats are best represented. Few studies were found on emerging POPs or on POPs recently included in the Stockholm Convention. Besides, the fact that the specimens in the analyses conducted in the studies reviewed were not separated by sex or age may conceal the potential risk of POPs to the conservation of bat populations. We recommend that future research goes beyond evaluating POP contamination in bats, but also analyzes their noxious potential, as wild populations may be declining over time as well as their roles in the ecosystem and in the economy.