HILO, Hawaii — Community concerns about infections acquired while swimming in Hilo Bay prompted a study spearheaded by then-University of Hawaii at Hilo undergraduate and lead researcher Tyler Gerken in 2018. The study was recently published in the Journal of Environmental Quality, identifying the origins of the high levels of bacteria that wash into Hilo Bay after heavy rainfall.


What You Need To Know

  • A study recently published in the Journal of Environmental Quality identifies the origins of the high levels of bacteria that wash into Hilo Bay after heavy rainfall

  • Researchers detected the highest concentration of staph and fecal bacteria in urban soils found in residential properties and farm lots; the lowest was found in native forests

  • Lead researcher Tyler Gerken began the study in 2018 after swimmers commented about acquiring staph or MRSA infections while swimming in Hilo Bay

  • According to co-author of the study, Tracy Wiegner, “Our way to reduce the amount of bacteria going into water bodies is to employ green infrastructure technology, which includes things like maintaining riparian (or streamside) wetlands, constructing wetlands for stormwater retention and beach grooming”

Collecting soil samples from urban, agriculture and native forest land areas in the Hilo Bay watershed, the research team found Staphylococcus aureus (informally known as “staph”), methicillin-resistant Staphylococcus aureus and fecal indicator bacteria in all the samples. The highest concentration was detected in urban soils found in residential properties and farm lots. The lowest was found in native forests, according to a UH Hilo news release.

The increase of MRSA and other fecal indicators in Hawaii streams after a storm poses a health threat to recreational water users. According to the researchers, identifying watershed bacteria sources is critical to implementing management actions to reduce risks.

“This research resulted from community members always talking about staph or MRSA infections that are acquired while swimming,” said Tracy Wiegner in the release. Wiegner is a UH Hilo marine science professor who co-authored the study.

Now a UH Hilo alumnus, Gerken is a Keaau native and descendant of kahuna laau lapaau or masters of traditional Native Hawaiian healing, which has fueled his dedication to environmental justice.

Louise Economy, also a co-author of the study, is an alumna of UH Hilo’s tropical conservation and environmental science graduate program and is currently employed by the Hawaii Department of Health.

“Our way to reduce the amount of bacteria going into water bodies is to employ green infrastructure technology, which includes things like maintaining riparian (or streamside) wetlands, constructing wetlands for stormwater retention and beach grooming,” explained Wiegner. “These techniques have been successfully used in the Great Lakes region of the United States to improve water quality and make it safer for swimmers.”

She added, “It’s the student’s interest in this community issue that really drove this project forward. Moving forward with our results, we want to share these with community members so they can make educated decisions about when and where they go swimming in the waters.”

Sarah Yamanaka covers events, environmental and community news for Spectrum News Hawaii.