Question

Which among the following statements is false?
(a) Oil slick in sea water increases D.O. value.
(b) The main reason for river water pollution is
industrial and domestic sewage discharge.
(c) Surface water contains a lot of organic
matter mineral nutrients and radioactive
materials.
(d) Oil spill in sea water causes heavy damage
to fishery.

Answer 1

$\star$ The false statements among the given lines is:

• The main reason for river pollution is industrial and domestic sewage discharge

Reason:

• River water pollution is not only polluted by industrial and domestic sewage discharge.

• It is also polluted by the surface runoff from agricultural fields.

• Presence of fertilisers and toxic pesticides in the water from agricultural fields are also an important reason for pollution.

$\star$ Other statements are correct because:

• Oil slick in seawater increases the biological oxygen demand because oil cuts of the the supply of atmospheric oxygen from water.

• Surface water does contain a large amount of of organic matter as waste, pesticides from agricultural fields, mineral nutrients from fertilizers and radiological waste from nuclear reactors.

• Oil spills in the sea cause severe damage to the fishery industry because innumerable sea fishes come to freshwaters for spawning and reproduction. Oil spills cause death of these fishes.

Hope It Helps.

Answer 2

Answer:

false statement =  

(b) The main reason for river water pollution is

industrial and domestic sewage discharge.

NOT only  industrial and domestic sewage discharege are responsible for river or water pollution . there are lots of other reason which pollute water

examples

eutripication  = sudden death of lakes or damp due to bloom algae which harm the aquatic life

acid rain =  when industrial smoke which contain harmful gases like So2 and Co  it attack on water life and make water polluted

oil pollution and global warming  are also reason for water pollution .

other statements are correct  oil slick in sea water increases dissoloved oxygen value

surface water contain organic matter

oil spill in sea water causes heavy damage .