Contaminant, Such as Chemical Waste in Rivers

This page is the CodyCross answer for the clue below from Welcome to Japan, Group 575, Puzzle 1 (Bullet Train).

Question is: Contaminant, Such as Chemical Waste in Rivers

and the answer is: POLLUTANT

Word Meaning:

POLLUTANT — A foreign substance that makes something dirty, or impure, especially waste from human activities.

Definitions from Wiktionary.