question: What causes increased pollution and levels of bacteria such as E. coli to rise in the Yarra River and its tributaries ?
answer: septic systems , as well as litter
turker_answer: Septic systems , as well as litter , caused increased pollution and levels of bacteria such as E. coli to rise in the Yarra River and its tributaries .
rule-based: Septic systems , as well as litter causes increased pollution and levels of bacteria such as E. coli to rise in the Yarra River and its tributaries .