HAVERHILL — A week after a sewer main break sent millions of gallons of wastewater into the Merrimack River, new tests continue to find dangerous levels of fecal bacteria downstream as state legislators press for federal assistance.
The Merrimack River Watershed Council (MRWC) said Tuesday that the river downstream of the Haverhill sewer main break continues to experience widespread unsafe bacteria levels four days after the city’s sewer line was repaired.
The organization also warned forecasted rainfall Tuesday could trigger a combined sewer overflow (CSO) in Haverhill, potentially bringing more bacteria to waters already struggling to dilute contamination released during the break.
Testing administered by the MRWC began at seven locations from Haverhill to the mouth of the Merrimack River on June 29. The sites include Route 113 bridge in Haverhill, Ferry Park in West Newbury, Deer Island in Amesbury, the Route 1 bridge in Newburyport, Harbormaster Pier in Newburyport, Salisbury Beach and Plum Island Light in Newburyport.
Samples on June 29 showed three of seven sites exceeded federal safety standards for fecal bacteria. Five of seven sites were unsafe on June 30, followed by six of seven last Wednesday morning, according to the council.
At about 10 a.m. Wednesday, Haverhill successfully installed a diversion pipe capable of handling the city’s typical sewer flow. Wednesday afternoon, six of seven sites were still unsafe, but testing appeared to improve Thursday, when only three of seven sites were deemed unsafe.
Conditions worsened again Friday, with six of the seven sites found unsafe, followed by five of seven on Saturday and four of seven on Sunday. Results from Sunday show dangerous levels of fecal bacteria at Salisbury Beach, measured four to five times above the recommended safety limit.
Testing at the Route 113 Bridge in Haverhill brought unsafe findings on June 30 and July 1, according to the council.
Findings are posted 24 hours later because of laboratory incubation requirements. Results from Monday’s water samples were expected to be available late Tuesday.
“It is important to stress that these results reflect sampling from Sunday and results can change considerably in 24 hours,” MRWC said.
“No one should assume these results can determine whether it is safe or unsafe at these locations today. It is also important to note that these results are from sites within the river and up to where the river meets the ocean.”
MRWC recommends that people avoid contact with the Merrimack River downstream of Haverhill, including Newburyport Harbor, until testing confirms the water is safe. The organization said it defers to the state on decisions involving ocean-facing beaches.
Unsafe fecal bacteria levels can cause gastrointestinal illness, infections and, in severe cases, death. The council said that the levels detected are unsafe for humans and pets, and particularly young people, the elderly and those with compromised immune systems.
Daily testing results will continue to be posted at merrimack.org until bacteria levels return to normal. Results are compared with the Environmental Protection Agency recreational water safety standards.
The emergency began June 26 when two breaks occurred in a 42-inch sewer force main following a heavy rainstorm in Haverhill. Before repairs were completed, the city estimated that 7 million to 10 million gallons of untreated sewage entered the Merrimack River each day.
City officials have reported that two temporary diversion pipes have been installed to prevent sewage from entering the river — the second installation occurring over the Fourth of July weekend.
However, the new temporary pipes will not be able to handle the same volume as the original infrastructure, so sewer discharges from CSOs could be larger and more frequent. The MRWC said Haverhill averages about 35 CSO events each year, and a median overflow releases about 60,000 gallons of wastewater.
Haverhill’s drinking water remains safe because it is supplied through a separate municipal water system.
“In this context, the sewer main break is a major disruption above and beyond what is typically discharged into the Merrimack River,” the MRWC said.
Meanwhile, Sens. Edward Markey and Elizabeth Warren sent letters earlier this week to the U.S. Department of Agriculture, the U.S. Small Business Administration, the Environmental Protection Agency and the Federal Emergency Management Agency regarding the possible need for federal assistance.
The senators mentioned environmental, public health and economic concerns affecting communities throughout the Merrimack Valley following the sewer line break.
“Officials are continuously monitoring the contamination levels in the river and on the North Shore to determine when it is safe for people to fish, work, and recreate in the waters,” Markey and Warren wrote. “Our offices and the Commonwealth have already been in touch with several of your agencies, and we are grateful for your engagement.”
The letter asked for the agencies to promptly review any request from Gov. Maura Healey and expedite all appropriate relief related to this incident.
Haverhill is also assessing the short- and long-term costs associated with the emergency response, repairing and replacing the damaged infrastructure.