According to a new WB report (Quality Unknown: The Invisible Water Crisis), the release of pollution upstream acts as a headwind that lowers economic growth downstream. Specifically, when Biological Oxygen Demand (BOD) – a measure of how much organic pollution is in water and a proxy measure of overall water quality – passes a certain threshold, GDP growth in downstream regions is lowered by a third. Meanwhile, in middle-income countries – where BOD is a growing problem because of increased industrial activity - GDP growth downstream of highly polluted areas drops by half.
High chemical fertilizer use has long-term consequences including stunting. Nitrate exposure in infancy wipes out much of the gain in height seen over the past half-century in some regions and harms children even in areas where nitrate levels are deemed safe. While an additional kilogram of nitrogen fertilizer per hectare increases agricultural yields by as much as 5%, the accompanying run-off and releases into water can increase childhood stunting by as much as 19% and decrease adult earnings by as much as 2%. This suggests a stark trade-off between using nitrogen to boost agricultural output and reducing its use to protect children’s health.
This report also reveals that enough food is lost due to saline waters each year to feed 170 million people every day – that’s equivalent to a country the size of Bangladesh. Such a sizable loss of food production to saline waters means food security will continue to be jeopardized unless action is taken. More salt in the water means less food for the world.
So, what can be done about it? First, there needs to be a reliable, accurate and comprehensive information about water quality. Second, prevention is better than cure. Sunlight is the best disinfectant but legislation, implementation and enforcement to reduce water pollution are equally important. Third, investment in wastewater treatment and reduce preventable pollution.