A researcher in the Milken School of Public Health found that nearly 17 million women and children in 24 sub-Saharan African countries are responsible for collecting water and carrying it long distances home – a task that may harm their health – according to a press release.

Although other studies have looked at the lack of access to clean water in these countries, Jay Graham, a professor of environmental and occupational health in the Milken school, and his colleagues were the first to look at the “absolute number affected and the gender imbalance in water collection labor,” a task that often takes more than 30 minutes per trip, according to the release.

“The journey to collect water every day harms health, uses up limited human energy and takes time away from other opportunities,” Graham said in the release. “By reducing the distance to water – preferably by having water piped to each property – many women and girls would be freed up for work, school or other activities.”

The researchers looked at data from international survey programs and determined that adult women were the primary collectors of water across the 24 countries, from 46 percent in Liberia to 90 percent in Cote d’Ivoire, according to the release.

Graham said in the release that carrying the heavy jugs of water, weighing 40 pounds or more, can cause health problems like pressure on the skeletal system that can lead to early arthritis or spinal pain.

Researchers also found that girls were much more likely than boys to be responsible for water collection – 62 percent and 38 percent respectively, according to the release. The effects on children included health problems like exposure to unclean water that can lead to serious diseases and missing school.

Graham added that women and girls are more prone to sexual violence while on water collection trips.

“We didn’t look at the underlying reason for the gender imbalance in water collection,” Graham said in the release. “However, in some African countries collecting water is considered a low status job and often falls to women and girls.”

Graham and the other researchers created a new metric that “allows public health leaders to plug in numbers of females versus males to get the gender ratio of water collectors,” according to the release. Graham added that he hopes his study will allow these public health leaders to take a closer look at the gender imbalance and attempt to fix it.

“Our study suggests water collection by children and gender ratios should be considered when measuring a nation’s progress toward providing better access to water,” Graham said in the release.