A. Mercury
B. Lead
C. Fluoride
D. Arsenic
Related Mcqs:
- Fluorosis (a bone disease) is caused by the presence of high concentration of ____________ in atmospheric air?
A. Hydrocarbons
B. Hydrogen fluoride
C. Hydrogen sulphides
D. Nitrogen dioxide - Lung cancer & DNA breakage are the major ill effects of excessive ozone exposure to human beings. Ozone layer depletion in the atmosphere is mainly caused by the presence of________________?
A. CO2
B. SO2
C. Hydrocarbons
D. CFC (chloro fluoro carbon) - Presence of bacteria in potable (drinking) water causes_________________?
A. Turbidity
B. Disease
C. Bad odour
D. Bad taste & colour - TLV of mercury in potable (drinking) water is about ______________ ppm?
A. 0.001
B. 0.1
C. 1
D. 5 - Thermal pollution due to excessive heat & temperature in the working place causes__________________?
A. Reduction in working efficiency of manpower
B. Fatigue
C. High breathing rate
D. All A., B. & C. - The amount of chemical coagulant added for treatment of polluted water ______________ with increase in temperature of the polluted water to be treated?
A. Decreases
B. Increases
C. Remain constant
D. May increase or decrease; depends on the chemical characteristics of polluted water - Brown spots in fabrics will be caused by washing with water containing large amount of___________________?
A. Iron
B. Zinc
C. Iodine
D. Bromine - Presence of dissolved impurities of ______________ is responsible for the red brownish color of water?
A. Carbonates
B. Bi-carbonates
C. Iron & manganese
D. Arsenic - Growth of ______________ is promoted by the presence of manganese in water?
A. Files
B. Algae
C. Micro-organisms
D. Mosquitoes - A man exposed to excessive noise level in the working environment may suffer from____________________?
A. Hearing loss
B. Rupture of ear drum
C. Nervousness & fatigue
D. All A., B. & C.
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