Agriculture and Environment: Coffee

Environmental Impacts of Production: Degradation of Water Quality

Coffee processing degrades freshwater bodies in many tropical ecosystems.

Traditionally, when "cherries" were processed at the plantations, coffee pulp was used as mulch on the crop.

Now that processing often occurs farther from the fields, pulp produced from wet pulping operations (which is the preferred and most common processing technique) is increasingly dumped in rivers.

Lowering oxygen levels in water
In the rivers it is a source of pollution because its decomposition uses much of the available oxygen, and the lower oxygen levels in water lead to fish kills. (This type of pollution is measured as biological oxygen demand, or BOD.)

A study in Central America in 1988 showed that processing 550,000 metric tons of coffee generated 1.1 million metric tons of pulp and polluted 110,000 cubic metres of water per day. This was equated with a city of 4 million dumping raw sewage into the region's waterways.

Biggest source of pollution in rivers
In that period, Costa Rica estimated that coffee processing was responsible for two-thirds of the pollution, as measured by total biological oxygen demand, in its rivers. As freshwater supplies become scarcer and demand for fresh water increases, this issue will become even more important (Manion et al. 1999).