WASHINGTON (BLOOMBERG) - Poor water quality saps one-third of potential economic growth in the most heavily polluted areas, according to a new global analysis by the World Bank that underscores how crucial clean water is to productivity.
"Deteriorating water quality is stalling economic growth, worsening health conditions, reducing food production and exacerbating poverty in many countries," World Bank Group President David Malpass said in a statement released with the report on Tuesday (Aug 20).
Gross domestic product growth falls by 0.82 percentage points in regions downstream of heavily polluted rivers, compared with an 2.33 per cent average rate, according to the report. In middle-income countries, the impact is even larger, with almost half of growth lost, and in high-income nations, GDP declines 0.34 percentage points.
Bank researchers based conclusions on three major types of water quality data: Monitoring stations or collected samples, satellite data, and computer-generated data built from machine learning models. They also emphasised that better data is needed to shed light on the issue.
"Global water quality monitoring is severely lacking," the researchers wrote.
Data automatically captured by satellite eliminates reliance on river or lake monitoring stations, and also benefits from being tamper-proof, preventing vested interests from modifying results. Such readings also show variations across lakes or rivers rather than quality at a single point which might be misleading, the researchers wrote.
The report recommends policy solutions such as better information gathering including with blockchain technology, greater prevention efforts, and more investment in protecting water resources.
The report said bacteria, sewage, chemicals and plastics can reduce oxygen in water and increase toxicity. In particular, increased nitrogen levels in water can impact growth and mental development among children and reduce future adult earnings by as much as 2 per cent compared with those who weren't exposed.
Nitrogen typically enters water supplies when applied as fertiliser in agriculture. That can raise farm productivity, but nitrates can damage the environment when they accumulate in ground water and there is runoff entering rivers, lakes and oceans.
High salinity also contributes to poor water quality, driven by more intense droughts, storm surges and rising water extraction. That in turn depresses agricultural yields by an amount that could feed 170 million people, or about the population of Bangladesh, according to the report.
The researchers, led by Richard Damania and Aude-Sophie Rodella, also noted increasing concern about microplastics and pharmaceuticals.
More than 90 per cent of the estimated 8.3 billion tonnes of plastic created since the 1950s has not been recycled, and there is limited information about safety thresholds for how much is safe in water supplies. Some studies have detected microplastics in more than 80 per cent of global freshwater sources, municipal tap water, and bottled water.
Pharmaceuticals are also entering the water supply at alarming rates. According to the report, one Indian wastewater treatment plant which serves a large drug-manufacturing region was found to have concentrations of antibiotics at 1,000 times the level toxic to some bacteria. Pharmaceuticals most commonly enter water supplies through human or animal urine and faeces, as 30 per cent to 90 per cent of most antibiotics can be excreted as active substances.