How mercury flows downstream

A comprehensive piece of research by USGS on the biogeochemistry of mercury in 8 different streams in US. Several interesting observations were made in the study but I will just highlight 2 points why mercury is an insidious pollutant posing a high degree of hazard.

1. The source of mercury in the study does not go directly into the water. Instead, mercury is carried by air or rain into streams and their watersheds. In other words, the watershed may not have any industry (e.g. mining, smelting, power generation) releasing mercury but mercury can still be transported from other areas by the atmosphere

2. Mercury can definitely move up the trophic levels to reach the top predator, usually fishes, if not man. It does not just remain in the abiotic environment, it can easily enter the food web right at the lowest level (e.g. algae) to affect the entire ecology.

How mercury flows downstream

via ES&T Online News on 3/11/09

A comprehensive study shows the correlations among landscape, mercury, and the life in streams and rivers.