Anonymous ID: b8321d April 30, 2021, 6:33 p.m. No.13553772 🗄️.is 🔗kun >>3809 >>3859 >>3921 >>4084 >>4170 >>4213 >>4303 Testing sewage for covid-19 It’s a cheap and effective way to map the spread of infection https://www.economist.com/britain/2021/05/01/testing-sewage-for-covid-19