Water crises will tend to get worse, specialist says

The phenomenon is not confined to drought but includes hydrological extremes such as the floods that are occurring more frequently in Brazil's South region.

By Elton Alisson, in São Carlos

Agência FAPESP – The water crisis that is afflicting some parts of Brazil is not a recent phenomenon but has been worsening for some time on a global scale. This crisis is characterized not only by drought and water shortages in the Southeast of Brazil and other regions but also by hydrological extremes such as the floods that are happening now in the South region.

This assessment was presented by José Galizia Tundisi, Honorary President of the International Ecology Institute (IIE), in a lecture on water resource management delivered on July 16, during the 67th Annual Meeting of the Brazilian Society for the Advancement of Science (SBPC).

The meeting began on July 12, and lasted until July 18, at the Federal University of São Carlos (UFSCar) in São Paulo State, Brazil.

According to Tundisi, water crises such as the one faced by Brazil in recent years have been occurring in different parts of the world for centuries but have become more severe since the middle of the twentieth century.

“In 2014, for example, the Northeast had its worst drought ever, while Foz do Iguaçu in Paraná suffered the worst floods in its history,” he said. “And this week Rio Grande do Sul and Santa Catarina have had exceptional amounts of rain, causing floods, loss of property and other hazards for the population.”

Among the causes of this worsening of water crises in Brazil and the world is urban population growth, according to Tundisi, requiring ever-larger amounts of water and producing huge volumes of solid and liquid waste while also fueling competition for water use.

Continental water resources, which represent only 2.7% of the planet’s fresh water, are used in multiple human activities, including industrial and agricultural production as well as the supply of potable water to homes.

Changes in land use, such as conversion of forest areas to cropland and cattle pasture, have affected evapotranspiration, the process by which water is transferred to the atmosphere by evaporation from the soil and other surfaces, and by transpiration from plants.

This combination of factors has brought about a worldwide degradation in water quality and an increase in floods and droughts that particularly afflicts people living on the peripheries of large cities, Tundisi said.

“The population of outlying neighborhoods in megacities such as São Paulo, Recife, Salvador, Fortaleza, Nairobi, Kolkata (Calcutta), New Delhi or Bangkok is highly vulnerable to hydrological extremes and lack of access to water,” he added.

According to a survey conducted in Cochabamba, Bolivia, by researchers working with the IIE, people who live in the center of large and medium metropolitan areas spend approximately 1% of their income on water, whereas peripheral populations spend approximately 10%, often being forced to buy water from private vendors (e.g., tankers, carriers) owing to the lack of a piped water supply system, Tundisi said.

“There are still 768 million people worldwide without access to adequate water sources and 2.5 billion people without decent basic sanitation. This represents a major failure of the world economy,” he stressed.

Pollution

In a study commissioned by UNESCO, the United Nations Educational, Scientific & Cultural Organization, Tundisi outlined the main problems that have driven water quality degradation in the last 150 years.

In the early nineteenth century, he recalled, European rivers were severely polluted by raw sewage. This problem intensified in the early twentieth century owing to rapid urban population growth.

In England, for example, the Thames was so polluted from Oxford to London that a series of cholera outbreaks in the 1840s and 1850s and the Great Stink of 1858 forced Parliament and Queen Victoria (1819-1901) to agree on the urgency of investment in basic sanitation. The quality of the water improved, but in the twentieth century it deteriorated again, and by the 1950s the Thames was little more than an open sewer, containing no oxygen.

Work began on greatly enlarged sewage works for London in 1964 and completed in 1974. The results have been spectacular, with much of the river now supporting aquatic life. “This was the first comprehensive clean-up of a major urban river in the world,” Tundisi said.

River pollution worsened worldwide during the last century owing to the increase in manufacturing and the production of large amounts of heavy metals. Radioactive waste accumulated in water bodies in the 1940s and ensuing decades because of atom bombs and nuclear tests. Surface and ground water became increasingly contaminated by garbage dumps in cities from the 1960s onward.

In recent decades the importance of persistent organic pollutants such as pesticides, herbicides and hormones as drivers of water degradation has increased, and all this has been exacerbated by global climate change since the early twentieth century, Tundisi noted.

“These processes took some 150 years in the industrialized countries but only about 70 years in developing countries like the BRICs,” he said.

“Rapid industrialization in the developing countries has led to an increase in the toxicity of both surface and ground water as well as economic effects and human health hazards, many of which are unknown.”

According to Tundisi, medical drugs and cosmetics used throughout the world are discharged into water bodies, where they dissolve and are not retained by water treatment systems.

Recent research has shown that sewage stations are accumulating antibiotic-resistant bacteria suspended in wastewater. This is another grave public health problem. “The highly sophisticated laboratory equipment needed to analyze all the substances dissolved in water is very expensive, and not all countries can afford it,” Tundisi said.

“We have a project with the European Union in which we suggest the installation of laboratories in South and Central America so that we can analyze all the substances present in water bodies and water supply systems of countries in these regions in order to develop solutions to eliminate them.”