The use of wastewater in Cochabamba, Bolivia: a degrading environment.

Abstract

In Cochabamba, Bolivia, wastewater is extensively used in urban and peri-urban agriculture. Both vegetable and fodder crops are irrigated with polluted water, i.e. diluted or partly treated municipal and industrial sewage containing high concentrations of pathogens, heavy metals and salts. Specifically in the downstream La Mayca area, where the farmers have an agreement with the municipal water and sewerage company, soil degradation has forced farmers to increasingly replace vegetable crops with more salt-tolerant fodder crops. In other areas around the city, cultivators deny using readily available wastewater, pointing to nearby wells as their water source. However, many wells are probably also polluted and do not yield enough water for the irrigated area served. Farmers state they are not confronted with specific health problems related to the use of polluted water, contradicting reports from local health workers. Low surface water flows and low rainfall, along with high (industrial) pollution and low wastewater treatment capacity mean that most of the water available to the farmers is of poor quality. Reduction of (industrial) pollution, increased treatment capacity and an integrated water management (IWM) approach, in which nearby good-quality groundwater could be used as a water source for blending with wastewater, represent options for improvement. However, strong traditional water rights, lack of urban planning, and weak institutions are constraints to the improvement of wastewater management in Cochabamba.

Salinity Implications of Wastewater Irrigation in the Musi River Catchment in India

“…A similar shift to fodder grass has occurred in wastewater irrigated areas in the vicinity of Cochabamba, Bolovia, where it has also been attributed to soil salinization (Huibers et al, 2004). In those fields with the highest salinity levels (in excess of 10 dSm -1 ) it is possible that even paragrass yields may be adversely affected in the not too distant future.…”

Wastewater Irrigation: The State of Play

“…Cochabamba involves direct and indirect reuse, whereas only indirect reuse occurs at the other two cities. Salt‐related problems associated with poorly treated effluent in Cochabamba have seen many farmers switch from vegetable production to more salt‐tolerant fodder crops (Huibers et al, 2004).…”

Soil Salinity and Exchangeable Cations in a Wastewater Irrigated Area, India

“…Wheat, for example, maintains 80% of its yield at root‐zone salinity of 12 dS m −1 compared to 5 dS m −1 for rice (Qadir et al, 2007). Vegetables are grown successfully in areas irrigated with wastewater in India (Bradford et al, 2003) and elsewhere (Hamilton et al, 2007), though salinity problems have likely forced farmers to switch from vegetables to more salt‐tolerant fodder grass (Huibers et al, 2004). The results from the Musi are consistent with these other studies in suggesting that salinity will likely reduce yields of some crop types and force farmers to change crop types.…”