Gel Spreads Toxic Mine Waste.

Water Technology News, October, 2002

Toxic "gels" that form downstream from mining sites may not only be suffocating fish but also push toxic chemicals further downstream, according to a report published in Science magazine.

An international team of researchers has been investigating the chemical processes that cause the gel to form in downstream waters from mines. According to the report, the gel results when runoff made acidic by mining or acid rain collects aluminum from local soils. The runoff then mixes with stream water that is less acidic, triggering chemical reactions that link the aluminum molecules together to form a polymer gel.

Scientists call the gel "floc" and say its influence is widespread, noting that mining disrupts about 240,000 square kilometers of the Earth's surface (about...