"Lake Sanabria is not leaving those charged with analyzing its waters equally impressed. The body of water is located inside a natural park in Zamora province, which receives some 700,000 visitors a year. Complaints about sewage being dumped there have raised the alarm. The International Biology Station (EBI), a company that runs an eco-tourism project and conducts studies in the area, is warning that conditions in the lake are getting worse, and that the damage will be irreversible in the mid-term." (Quoted from article)