Biodiversity - GMS-EOC

Farmer in the floating gardens of InleLake, Myanmar (upper left); womenfishers with scoop nets (lower left);sunrise over the Shan Hills, Inle Lake,Myanmar (right)Pollution from Many SourcesMost arable land in the subregion is alreadycultivated. New technology and intensified farmingto feed the growing population probably will meanincreased fertilizer and pesticide use. Fertilizersspeed up eutrophication (a process that reduces theamount of available oxygen) and reduce fishproduction in rivers and lakes that receive runofffrom agricultural lands. High levels of pesticides arealso toxic to fish, but even low concentrations ofpesticides can reduce fecundity because theirchemical structures mimic female hormones. Theproduction, distribution, and application ofagricultural chemicals must be better regulated toavoid misuse or overuse, and to protect very valuablefisheries.Industrial, municipal, and domestic wastes willincrease as the population grows. Like agriculturalchemicals, these wastes hasten eutrophication andincrease the toxicity of receiving waters. But becausethese pollution sources are more localized,appropriate centralized waste collection andtreatment can often lessen their detrimental effects.Nevertheless, because factory wastes are oftenaccumulated in storage ponds, breaches in the pondwalls due to floods or other causes can release verylarge quantities of pollutants in a short time, causingmassive fish kills. Better facilities for managingindustrial wastes and controlling toxic spills areurgently needed. Cities, towns, and factories mustbuild or upgrade sewage collection and treatmentfacilities, and treat their wastes before dischargingthem into nearby rivers.98 Greater Mekong Subregion Atlas of the Environment