A new paper published in Nature Climate Change suggests that urban water quality has not changed much from the past century.
This is a welcome result that suggests the long-held assumption that urbanization and water quality have a lot in common is not necessarily wrong, says lead author Eric Fung, an associate professor of civil and environmental engineering at MIT.
While water quality was improved by urbanization, urban areas have always been less polluted than rural areas.
The new study, by a team of researchers from MIT and other institutions, finds no connection between water quality and urbanization.
Fung says the study’s results are consistent with a widely held view that urban development is not associated with changes in water quality.
Water quality is not impacted by urban density or size.
Fung says this study suggests that the relationship between water and urban growth is more complex than previous research had suggested.
Urbanization and environmental changeFung and his coauthors looked at data on water quality, and their findings are consistent.
As the authors note, urban development in cities increases the quantity of nutrients in the water and reduces the amount of contaminants in it.
They also found that urban dwellers tend to have more water-holding capacity, which means they have more capacity to produce drinking water.
“As a result, urban populations have greater overall water-use capacity than rural populations,” Fung explains.
And while cities may increase water use, the amount they use remains constant.
In contrast, rural populations have more “marginal water” or water that is needed for human activities, like watering crops or cleaning buildings.
Researchers also found the amount cities consume from rivers is largely unaffected by urban growth, and that urban population densities are not correlated with water consumption.
When it comes to water quality impacts, Fung and colleagues note that urban populations tend to be healthier than rural ones.
And that’s in part because water use is more heavily regulated in urban areas, which can help to reduce pollution.
In their study, Fultz and colleagues found that the average urban population has significantly less pollution than rural residents.
The researchers say their results support a hypothesis that the urban population’s use of water is inversely correlated with its use of pollutants.
The relationship between pollution and water use in urban centers is strongest for nitrogen, carbon dioxide and ozone, which are the main sources of pollution.
The researchers also found there was no relationship between urban population density and pollution, and no relationship with urban water use.
They note that this could be due to differences in water use by different populations.
In the future, the authors plan to expand their research to look at other factors that may impact water quality such as urban sprawl and changes in precipitation.
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Original article on Live Science.