Amid concerns that the state is seeing a post-holiday coronavirus surge, the amount of virus found in the waste water at the Massachusetts Water Resources Authority’s Deer Island treatment plant is sending a disturbing signal, reaching the highest levels yet.
The new highs were reached for both the northern section of the MWRA system, which includes Boston and a group of communities to the north, and the southern section, which includes a group of communities to the south and west of the city.
The pilot program looks for SARS-CoV-2 RNA copies per milliliter of waste water. Officials are hoping the tests can serve as an early warning system for virus surges. Like other coronavirus metrics, the charts show two major surges, one in the spring and one beginning in the fall.
The data reflects tests taken as recently as Monday. Cambridge-based Biobot Analytics, which conducts the testing, says it has found that the amount of virus in the waste water is correlated with newly diagnosed coronavirus cases four to 10 days later.
The MWRA noted on its website that there had been a problem with sampling equipment that affected northern section samples from Dec. 31 through Jan. 4. But it said the problem had been corrected as of Jan. 5.
Ryan Huddle of the Globe staff contributed to this report.
Martin Finucane can be reached at firstname.lastname@example.org.