Lake Titicaca

The highest navigable lake in the world, the ancient Lake Titicaca is home to 530 aquatic species and supports over 2 million people. "Tucked between snow-capped mountains, Lake Titicaca was once worshipped by the Incas, who proclaimed its deep blue waters the birthplace of the sun. These days the shores of South America’s largest lake are littered with dead frogs, discarded paint buckets and bags of soggy trash. Less visible threats lurk in the water itself: toxic levels of lead and mercury . . . Untreated sewage water drains from two dozen nearby cities and illegal gold mines high in the Andes dump up to 15 tons of mercury a year into a river leading to the lake." In addition to pollution, Lake Titicaca faces threats of overuse and receding water levels due to climate change, while introduced fish have led to a decline in native species.