—————— —should be treated chemically before deposing it to rivers.

——Industrial waste——— should be treated chemically before deposing it to rivers.

=》The waste from factories & industries are highly acidic/base. This leads to the increase/decrease of the pH value of water in the rivers making it contaminated & unfit for drinking. This also causes a huge problem for aquatic organisms.

=》Industrial waste should be neutralized before depositing it into water bodies to reduce these risks.

⚜ Hope it helps :))

answer; i do believe the correct answer is (river); /// good luck

1.solid

2.carbon dioxide

3.helium