Citizens should avoid contact with water in the Nogales Wash and Potrero Creek due to the ongoing potential for the waterways to be contaminated with sewage from Mexico, the Arizona Department of Environmental Quality said on Tuesday.
ADEQ first warned the public about the risk of contamination in January after pumps failed at the Los Alisos wastewater treatment plant in Nogales, Sonora, sending sewage into north-flowing drainages and across the U.S. border. Tuesday’s alert reiterates that concern and makes clear that the underlying cause of the problem has yet to be fully addressed.
“Untreated sewage carries pathogens that pose a risk to human health and the environment,” ADEQ said in a news release. “People and animals that come into contact with untreated sewage are at risk of infection from those pathogens.”
During a meeting in Nogales on Sept. 12, an engineer from Mexico’s International Boundary and Water Commission said Los Alisos was struggling to reach 50 percent of its wastewater processing capacity as authorities continued to repair and replace faulty equipment. In its announcement Tuesday, ADEQ said that “while the pumps have been repaired or replaced, an issue with electrical connections continues to be addressed” at the plant.
During a meeting of the Nogales City Council last week, Councilman Marcelino Varona, Jr. said the problem had “escalated” and that the city had received “a lot” of complaints about the smell from the wash.
He blamed the Nogales, Sonora municipal government.
“They’re not carrying out the responsibilities of taking care to make sure that that dark water doesn’t come into our community,” he said.
Varona also said during the Oct. 2 meeting that the mayor of Nogales, Sonora had sent an email to city manager of Nogales, Ariz. promising to take care of the issue by the previous day, but that no progress had been made.
Cross-border runoff flows north through the Nogales Wash, which joins with Potrero Creek just north of city limits and, soon after that, with the Santa Cruz River. Depending on volume and frequency, ADEQ said on Tuesday, sewage overflows from Mexico could threaten the Santa Cruz River.
ADEQ recommended that members of the public take the following actions:
• Avoid contact with the water in the affected area, which includes wading, drinking and washing. If you have contact with the water, rinse using soap and clean water immediately.
• Take care that pets and livestock do not drink potentially affected water. Pets can be especially susceptible because they tend to drink while in the water and lick their fur after exposure. Rinse pets using soap and clean water.
• If you think that your health or that of your pet or livestock has been affected from exposure to raw sewage, seek medical treatment immediately and advise the County Health Department about the exposure.