In response to the partial breach of the International Outfall Interceptor (IOI) in Santa Cruz County, officials with the Arizona Department of Environmental Quality (ADEQ) initiated daily water quality sampling on July 26, 2017.
ADEQ’s initial testing covered a variety of contaminants of concern, including heavy metals. Ongoing testing is focused on E. coli and nutrients because heavy metals were not detected in initial test results. Test results are available on the Arizona Emergency Information Network (AzEIN). ADEQ is continuing to conduct ongoing daily sampling at several locations in Arizona both upstream and downstream of the IOI breach, stretching from the City of Nogales to an area southwest of the City of Eloy, Arizona.
ADEQ’s recent test results in response to the IOI breach confirm both elevated levels of E. coli upstream of the IOI breach, and substantially elevated levels of E. coli downstream of the IOI breach and, as such, ADEQ recommends the public avoid contact with this water.
ADEQ data analysis is ongoing and focused on determining the extent of the increase in E. coli levels from the IOI breach because all sampling locations in Santa Cruz County are located within an area designated as "impaired" for E. coli, meaning water quality in the area known as the Nogales Wash, historically and consistently contains levels of E. coli in excess of state surface water quality standards.
As the Nogales Wash flows into the Santa Cruz River, E. coli levels remain higher than state standards, but lower than immediately downstream of the IOI breach.
ADEQ will continue daily sample collection and testing until the IOI is repaired, no longer contributing to the existing E. coli impairment and is satisfied that adequate data have been collected to characterize the discharge.
Santa Cruz County Health Services recommends to those who live within the county, along the Santa Cruz River, and have a private well within 100 ft. of the waterway have their wells tested for contamination. Even in the absence of untreated wastewater, storm flows are typically high in pollutants that can be harmful.
The Department of Agriculture shares the concerns of livestock owners and farmers in the region. Until there is more information about the extent of the situation, it is recommended not using water from the Santa Cruz River to water food crops or gardens. Livestock should not be in the river or drinking from it.
Work continues on the IOI to repair the breach discovered last week near the intersection of Old Tucson Road and the Nogales Wash.
Officials ask that the public refrain from entering into areas where repair work is underway for the safety of the public and employees working in the area. Drivers should be especially careful in areas where repair crews are working near roadways.
As a reminder, the Nogales International Airport has restricted the use of drones within one nautical mile around the crew worksites.
A hotline (520-375-7784) is available for public and media inquiries between the hours of 8 am and 5 pm, Monday through Friday.
Updates will be posted on the Santa Cruz County Facebook and Twitter @santacruzaz. Public Health and Safety information is also available at santacruzcountyaz.gov and ein.az.gov.