- Slides: 14
Water Pollution – Causes, Effects & Rectification Measures � � As per the eleventh five year plan document of India (2007 -12), there about 2. 17 lakh quality affected habitations in the country with more than half affected with excess iron, followed by fluoride, salinity, nitrate and arsenic in that order. Further, approximately, 10 million cases of diarrhoea, more than 7. 2 lakh typhoid cases and 1. 5 lakh viral hepatitis cases occur every year a majority of which are contributed by unclean water supply and poor sanitation. Top-most priority shall be given for addressing water quality problems in all quality affected habitations with emphasis on community participation and awareness campaigns. It is mandatory to conduct timely water quality surveillance and monitoring by setting up of water quality testing laboratories strengthened with qualified manpower, equipment and chemicals.
Causes of Water Pollution can occur either in Raw Water or in Distribution Network � Raw Water ◦ Discharging of Industrial Effluents nearby source ◦ Presence of metals & harmful chemicals in source water. Ex: Lead, Manganese, Iron, Fluoride, Arsenic etc. ◦ Biological contamination due to open defecation, leachate from dump yards, disposal of animal carcasses near sources ◦ Excessive use of Pesticides and Insecticides, which find their way through run-off ◦ Treated Water in Distribution Network �Water Contamination can occur due to leakages in pipelines accountable to old/ rusted pipes �Presence of defective joints/ improper maintenance of HSCs �Seepage of sullage/ septage due to presence of leaks or build up of negative pressures in the distribution system �Possibility of contamination increases in areas having UGD network �
Health Hazards posed by contaminated water � � Biological contamination causes Explosive Diarrhoea, Dysentery, Cholera, Polio and may even lead to death Lead poisoning causes anaemia Fluoride causes Fluorosis Arsenic causes Encephalopathy, Diarrhoea, Heart diseases and may even lead to cancer
Rectification – Preventive Measures � � � BIS 10500: 2012 specifies the acceptable limits and the permissible limits in the absence of alternate source. It is recommended that the acceptable limit is to be implemented as values in excess of those mentioned under Acceptable render the water not suitable. Such a value may, however, be tolerated in the absence of an alternative source. However, if the value exceeds the limits indicated under permissible limit in the absence of alternate source, the sources will have to be rejected.
; Collection of Water Samples for testing – IS 3025: Part-I � � � In the case of samples for the determination of physico-chemical parameters one simple precaution is to fill the flasks completely and stopper them in such a way that there is no air above the sample. Use of opaque containers or brown ( non-actinic ) glass containers to reduce the photosensitive activities to a considerable extent Clean new containers thoroughly in order to minimize possible contamination of the sample For samples for determination of pesticides, herbicides and their residues —Clean the containers with water and detergent, followed by thorough rinsing with distilled water, then oven dry and cool before rinsing with hexane or petroleum ether. Finally dry with a stream of carefully purified air or nitrogen. For samples for microbiological analysis — The containers shall withstand a 100 o. C sterilization and shall not produce or release at this temperature any chemicals which would either inhibit biological activity, induce mortality or encourage growth.
Collection of Water Samples for testing � � Sample Volume: A two-litre sample is normally sufficient for most physical and chemical analysis. However, the quantity may be varied depending upon the type of analysis, methods used etc. Types of Samples: ◦ Spot Samples ◦ Periodic Samples at fixed time intervals ◦ Periodic samples taken at fixed flow intervals ◦ Continuous samples taken at fixed flow rates ◦ Continuous samples taken at variable flow rates ◦ Composite Samples
Sample Locations � � � Rivers, streams and canals - Samples should be collected. as far as possible, from midstream at mid depths. Ground water - Whenever possible, sample should be collected after pumping the well or bore hole for a period of at least an hour or two. This ensures drawal of new water from aquifer. Depth below ground level or reference level at which the sample is taken, should be recorded. Drinking water supply - The sampling point should be located at a place where all reactions of the disinfecting agent are completed and also some residual disinfectant is present. The usual sampling position is a tap on a pipe connected directly to the pumping main, as close as possible to the reservoir. Many service reservoirs fill and empty through the same main. Sampling should be made when reservoir is being emptied.