Jan 10, 2023

Controls of Mercury Toxicity by Subtropical and Tropical Mangrove Ecosystems


Mercury is a toxic and persistent metal that occurs naturally in the environment but human activities have accelerated its release into the environment. Ambient mercury is usually less toxic but will become highly toxic when transformed into methylmercury by reacting with certain bacteria. Methylmercury can bioaccumulate in the food webs, thus endangering food safety and human health. The WHO has identified mercury as one of the top 10 chemicals of major public health concern, which can harm our nervous, reproductive, and immune systems and pose a particular threat to children and pregnant women.

Until now, little is known about the formation of methylmercury in mangrove wetlands which have very high ecological and conservation values and are important sources of seafood for local populations. In this project, a team of scientists from seven countries/regions (HK, Chinese Mainland, South Korea, Thailand, Australia, Ghana and the US) will tackle this important question. Seasonal samples from selected mangrove wetlands will be collected to examine the relationship between mercury and ambient conditions and if different mangrove wetlands would behave similarly or differently in producing methylmercury and at what levels.

This project would be the first study of its kind to investigate mangroves across large geographic gradient using the same methodology, which is crucial for systematically inquiring a question of diverse environmental types. The results will help generalize the key environmental mechanisms in regulating the atmospheric deposition of mercury onto mangrove wetlands and the conversion of mercury to methylmercury, and form the basis of larger projects on mercury cycling and other issues related to mangrove ecosystems. The findings will also have implications for environmental policy to manage mangroves as well as guidelines for consuming seafood from mangrove swamps.