According to studies done by the Minnesota Pollution Control Agency, the lakes and streams across Minnesota are contaminated by pharmaceuticals, cosmetic ingredients, and endocrine-disrupting compounds. Even in remote areas of the state, chemicals such as antibiotics, nicotine breakdown products, antidepressants, and medications to regulate diabetes, cholesterol, and blood pressure, were detected. The insect repellent DEET was detected in 91% of the lakes studied. Previous studies showed that these compounds often turned up downstream from wastewater treatment plants but recent research has shown that they are also found even in remote lakes or upstream waters.
Researchers believe that these chemicals enter the water table through septic systems and stormwater __________ and are not impacted by wastewater treatment plants.
A) collection
B) pollution
C) runoff
D) treatment