In a water body polluted with biodegradable organic compounds,
1. the BOD and DO content are low
2. the BOD and DO content are high
3. the BOD is low and DO content is high
4. the BOD is high and DO content is low
In an algal bloom, the cause of death of other algae is usually:
1. toxins
2. decreased DO
3. decreased sunlight
4. decreased nutrients
The world’s most problematic aquatic weed, “The terror of Bengal”, is the name given to:
1. | Zostera | 2. | Ceratophyllum |
3. | Eichhornia | 4. | Parthenium |
Apart from DDT, what else is known to undergo biological magnification in aquatic food chain?
1. | Nitrates | 2. | Phosphates |
3. | Mercury | 4. | Calcium |
An increase in concentration of the intoxicant at successive trophic levels is known as:
1. | Eutrophication | 2. | Biomagnification |
3. | Bioremediation | 4. | Biofortification |
High concentrations of accumulated DDT in birds:
1. kills pathogens in their blood
2. causes sterility by affecting gametogenesis
3. leads to premature breaking of eggs
4. causes spasticity of the muscles of the body
Hot wastewater discharged from industries into water bodies:
1. | increases the nutrient content of the water body |
2. | decreases the BOD of water |
3. | is considered a water pollutant |
4. | is desirable as cool water is more damaging to aquatic life |
Ecological sanitation, also known as 'Ecosan', is a new paradigm in sanitation that:
1. | eliminates the use of conventional pesticides to decrease environmental insult |
2. | recognises human excreta and household wastewater as resources that can and are recovered, treated, and reused |
3. | emphasises the disposal of solid waste in sanitary landfill sites |
4. | emphasises the need for strict legislation against polluting industries. |