GS IAS Logo

< Previous | Contents | Next >

5.14.5. Trigger Effect of Acid Rain on Pollutants:


A low pH of the rainwater and subsequent increased acidity in the environment can trigger off or aggravate the effects of certain harmful pollutants.

(i) Mercury:


Methyl mercury and related short chain alkyl mercurial compounds are most dangerous to humans, as they accumulate in edible fish tissue.

Although acid deposition may not increase the production of methyl mercury, it may increase the partitioning of methyl mercury into the water column.

The use of lime has helped in reducing the mercury levels in fish.

(ii) Aluminium:


Acidified waters are known to leach substantial amounts of aluminium from watersheds.


Even at relatively low levels, aluminium has been implicated in dialysis dementia, a disorder of the central nervous system, which may be toxic to individuals with impaired kidney function.

(iii) Cadmium:


Cadmium can enter the drinking water supply through corrosion of galvanized pipe or from the copper- zinc through corrosion of galvanized piper or from the copper-zinc solder used in the distribution systems.

A decrease in water pH from 6.5 to 4.5 can result in a fivefold increase in cadmium and could cause renal tubular damage.

(iv) Lead:


Foetuses and infants are highly susceptible to drinking water lead contamination.


High blood lead levels in children (>30 mug/Ml) are believed to induce biochemical and neurophysiological dysfunction.

However, lower than normal blood levels of lead can cause mental deficiencies and behavioural problems.

(v) Asbestos:


Asbestos in natural rock can be released by acidic waters.


Do you know?


Tree ferns like Cyathaea and Alsophila have erect rhizomes with generally unbranched trunks, topped by a crown of graceful, feathery fronds that form a rosette at the apex.