The World Bank says the world is facing a water-quality crisis that is eliminating a third of potential economic growth in heavily polluted areas, while also threatening human and environmental wellbeing.

In a report, titled ‘Quality Unknown: The Invisible Water Crisis’, published last week, the World Bank highlighted how a combination of bacteria, sewage, chemicals and plastics could suck oxygen from water supplies and transform water into poison for people and ecosystems.

In compiling the report, the World Bank compiled the world’s largest database on water quality, with data gathered from monitoring stations, as well as through the use of remote sensing technology and machine learning.

“When biological oxygen demand – a measure of how much organic pollution is in water and a proxy measure of overall water quality – crosses a certain threshold, then the gross domestic product in downstream regions drops by as much as a third, owing to impacts on health, agriculture and ecosystems,” explained World Bank group president David Malpass.

He said nitrogen – which, applied as fertiliser in agriculture, eventually entered rivers, lakes and oceans where it transformed into nitrates – was a key contributor to poor water quality.

The report stated that early exposure of children to nitrates affected their growth and brain development, impacting on their health and adult earning potential. The runoff and release into water from every additional kilogram of nitrogen fertiliser per hectare could increase the level of childhood stunting by as much as 19% and reduce future adult earnings by as much as 2%, compared with those who were not exposed, the report pointed out.

The report also found that, as salinity in water and soil increased – owing to more intense droughts, storm surges and rising water extraction – agricultural yields fell.

“The world is losing enough food to saline water each year to feed 170-million people,” said Malpass.

The World Bank said economic growth and water pollution were intrinsically linked.

Nearly all forms of production create pollution as a by-product. Because water is needed for life, health and economic production, the impurities generated by upstream polluters may affect downstream users.

“On the understanding that eliminating all water pollution is too costly and infeasible, regulators and policymakers must make decisions about the appropriate level of water pollution,” the report said, adding that this called for weighing the benefits associated with the polluting activity against the costs of pollution.

The World Bank further explained that nearly all growth generated some by-product and that by-product was often discharged into waterways or soils, which eventually found its way into larger rivers.

Simultaneously, the presence of water pollution impacted on economic activity, whether through increasing health costs, reducing labour productivity, raising costs for businesses or reducing agricultural yields.

This two-way relationship makes establishing casual impacts between economic activity and water pollution challenging, the report stated.

The report recommended a set of actions that countries could take to improve water quality, including new environmental policies and standards; accurate monitoring of pollution loads; effective enforcement systems; water treatment infrastructure supported with incentives for private investment; and reliable, accurate information disclosure to households to inspire citizen engagement.

The World Bank said new technologies could be harnessed to improve enforcement in circumstances where policy implementation deficits were prominent.

For example, smart contracts, which have rules written in computer code that are embedded in a blockchain and automatically execute when the conditions are met, could be used to enforce payment from polluters.

The bank’s report said long-standing assumptions about wastewater treatment infrastructure also needed to change – investments had to be scaled up but also needed to become more effective.

More than 80% of the world’s wastewater, and more than 95% in some developing countries, was still released into the environment without treatment, the report pointed out.

Wastewater Treatment There was, therefore, an urgent need for greater investment in wastewater treatment plants, especially in heavily populated areas. The report found that, at times, investments in wastewater treatment facilities led to little measurable improvement in water quality, representing a waste of scarce public funds.

“The clear implication is that investments need to be accompanied by appropriate incentive structures that monitor performance, penalise profligacy, and reward success. Moreover, the large gap in public-sector resources suggests the need for new models that attract private investments,” the report stated.

The World Bank also recommended better land use policies and smart spatial planning, which were critical for protecting water supplies.

Forests and wetlands acted as natural buffers that absorbed excessive nutrients that would otherwise pollute waterways.