The swimming area at Silver Sands State Park in Milford has reopened, according to the Department of Energy and Environmental Protection. Wadsworth Falls State Park in Middlefield remains closed. DEEP said it retested the water on Wednesday and expects to get results on Thursday. The waterways closed after officials detected the presence of certain bacteria in samples. These bacteria \u2014 E. coli in freshwater and enterococci in saltwater \u2014 are not disease-causing pathogens, but they can indicate a potential fecal contamination from human sources or other warm-blooded animals, according to Tracy Lizotte, an environmental analyst with DEEP. High levels of this bacteria can occur for different reasons, but Lizotte said one of the most common is due to stormwater runoff, which carries dog and other wildlife feces into the water. With heavy rain, the sewer system may not be able to handle the influx of water, causing untreated sewage going into waterways. \u201cAt some of our beaches we have significant wildlife population such as geese that frequent our swimming areas that we believe cause the beach closures,\u201d Lizotte added.