Presence of excess nitrates in river water indicates:
A. Recent pollution of water with sewage.
B. Past pollution of water with sewage.
C. Immediate pollution of water with sewage.
D. No pollution of water with sewage.
Answer:B
Presence of excess nitrates in river water indicates:
A. Recent pollution of water with sewage. B. Past pollution of water with sewage. C. Immediate pollution of water with sewage. D. No pollution of water with sewage.