Abstract

Artisanal gold mining is known to cause high levels of mercury (Hg) contamination to human populations, due mainly to many miners burning gold amalgams without the use of safety equipment and/or mercury capture systems. In Portovelo-Zaruma, Ecuador, there are more than 10,000 people directly involved in artisanal mining. As Hg vapour accumulates in the kidneys and brain, it is important to investigate potential agents that may be effective in helping to detoxify contaminated individuals. In this study, selected vegetable and fruit juices were evaluated for their mercury (II) binding capabilities and their potential use as Hg detoxifying agents. Vegetables and fruits were selected based on results from a survey completed in January/2015 on readily available and frequently consumed foods in the mining district of Portovelo. Mercury (II) binding capabilities were measured by a simple spectro photometric method using diphenyl thiocarbazone (dithizone) to determine the amounts of mercury (II) in the juice samples. Juices from the Families Brassicaceae (kale, broccoli, cabbage, cauliflower), Amaryllidaceae (garlic), and Solanaceae (bell peppers) were the most active in binding to mercury (II). Little binding activity was present in other tested juices, including beets, carrots, celery, green apples, tamarillos, and tomatoes. In addition, no correlation was found between reported methionine, cysteine, and selenium content in analysed juices and Hg (II) binding activity. Assessment of bioavailability of methyl mercury (Me Hg) in tuna using an in vitro digestion model in the presence of vegetable and fruit juices has been initiated to determine the breakdown and binding of mercury in the juices.

Keywords: Mercury decontamination; Hg (II) binding activity; Artisanal gold miners; Ecuador