Blog: Valley Water working to reduce methylmercury (toxins) in local waterways
For more than 15 years, Valley Water has measured mercury levels in reservoirs and creeks in the Guadalupe River Watershed and studied ways to reduce the metal’s harmful impacts. Parts of the Guadalupe River watershed, which covers about 171 square miles, are contaminated with mercury from the former New Almaden Mining District. The mining and processing of mercury occurred in the area from 1845 through 1971. These operations released large amounts of mercury into parts of the Guadalupe River watershed, which flows into South San Francisco Bay. Mercury-enriched sediment from mining waste made its way into creeks and reservoirs within the watershed. Creeks flowing in the watershed carry that sediment down the Guadalupe River to San Francisco Bay, especially during wet years.