English, asked by dthakur2511, 4 months ago

Q30. Sewage from the nearby town was dumped sento
the sea, which among the given conditions.
would happen in the above ecosystem ofter
miscing of sewage into the water.
i) Biochemical oxygen demand (BOD) of receiving
sweater body increases
( dissolved oxygen of receiving water body line-
reases.
will It will cause mortality among fish and
other & aquatic creature.
(1) It will lead to nutrient enrichment of
receiving waterbody.
a) i, iii, i

Answers

Answered by Rameshjangid

Answer:

The correct option is, i, iii, iv

Explanation:

When sewage, having biodegradable organic matter is released into the water body, microorganisms involved in the biodegradation of organic matter (in the receiving water body) consume a lot of oxygen to decompose the sewage and as a result, there would be a sharp decline in dissolved oxygen downstream from the point of sewage discharge and biological oxygen demand (BOD) would increase. The presence of sewage causes nutrient enrichment (large amounts of nutrients) in water which causes excessive growth of planktonic (free-floating) algae, called an algal bloom. Algal bloom causes deterioration of water quality and fish mortality.