Read the following paragraph from the section "There Are Still Chemicals In The River." The Bronx River was once clean. Native Americans used to fish in it. The river's health changed by the 1850s. That's when it started getting polluted. It was pumped full of garbage, sewage and other waste. It became full of dangerous chemicals. This included PCBs, lead and mercury. What is the focus of this paragraph?
A.
when the government made rules about chemicals in the Bronx River
B.
what chemicals were found in turtles from the Bronx River
C.
how the Bronx River became polluted
D.
why the Native Americans fished in the Bronx River