Toxin levels spike, prompting drinking water emergency in Northern California
Amid a withering drought, a severe harmful algal bloom in California’s second-largest freshwater lake is producing exceptionally high toxin levels, resulting in a drinking water emergency for hundreds of residents who draw water directly from Clear Lake. The colorful but noxious mats of cyanobacteria in the Northern California lake have also led to difficulties for public utilities that have more sophisticated treatment systems than individual households.