Environmental mercury that is absorbed in the diet can have serious effects on human health, including neurological and reproductive effects. The Pearl River Delta in south China has transformed from an agricultural centre to a manufacturing centre during the past few decades.

The bioavailability and toxicity of contaminants such as heavy metal(loid)s is underpinned by their bioaccessibility. Some heavy metal(loid)s are ingested accidentally, such as arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb).