Quality of water used for drinking purposes is of considerable importance as poor water quality affects human and animal health. Physical, chemical and biological components of water influence its quality. Chemical constituents which lower the quality of water cannot be easily removed unlike physical and biological constituents. A number of chemicals are known to affect the quality of ground water resulting in the occurrence of a many non-communicable diseases.
Drinking water in some pats of the Dry Zone has a fluoride concentration ranging from 6-8 mg/liter although the WHO limit is 1.5 mg/liter. High fluoride levels in potable water causes children to have brown decaying teeth. Fluoride at high levels can cause severe skeletal fluorosis and it can disrupt the actions of many key enzymes. Nitrate is one of the most common groundwater contaminants in agricultural areas. The high nitrate content in groundwater is mainly from irrigation run-off from agricultural fields where chemical fertilizers have been used indiscriminately. Ground water in Kalpitiya is reported to contain nitrate levels above 10mg per liter which is the WHO standards for drinking water. The presence of nitrite in the digestive tract of newborns can lead to a condition called Methemoglobinemia, which is the most significant health problem associated with nitrate in drinking water. Those pesticides which do not degrade in a short time tend to pollute the water bodies causing the water quality be lowered. Phosphates present in phosphatic fertilizers tend to get washed into water bodies causing eutrophication. The result of this process cause water quality to decrease
Water quality is closely linked to water use and to the state of economic development and has been heavily impacted by industrial and agricultural chemicals. Water supply for various sectors of society is getting increasingly complicated as water contamination escalates, and awareness grows among water users of the links between upstream polluters of water with downstream water users.
Chronic Renal Failure
A disease called Chronic Renal Failure ( CRF), which is widespread in the North Central Province, part of North Western and Uva provinces is attributed to a toxic element/compound presenting drinking water. This disease characterized by a slow, progressive, asymptomatic development, frequently starting at a younger age group. Around 10,000 people, mainly in the three provinces indicated above are currently undergoing treatment for this disease. In 2005, Anuradhapura Teaching Hospital alone recorded 742 live discharges and 140 deaths due to CRF.
According to separate studies carried out by a number of Sri Lankan Scientists, CRF is attributed to high levels of one or more chemicals in drinking water. Among these constituents are cadmium, fluoride, aluminum, toxins released by Blue Green Algae, and pesticides. According to a paper presented at a recently held seminar, reported in the Island of 17th March 2011, arsenic and mercury are added to this list. The accuracy of this finding has to be verified, for if it is correct, it is a serious situation. According to the scientist who has presented this paper, arsenic (As) and mercury (Hg) are present in drinking water and also in rice. It is not clear how these two elements have gone into water and rice. The scientist who reported the occurrence of As and Hg should have looked into the source of these two elements. Are these present in soil or did it come from some agricultural inputs such as fertilizers or pesticides?.
A draft research proposal to determine the causal factor/s of CRF was prepared by a team of experts and a research programme is supposed to have been initiated by the Ministry of Health, in October 2008. The final report was expected to be submitted in Dec. 2009. But, according to WHO country Director, as reported in The Island 18th March 2011, the report will be released only in mid 2011, 18 months after the due date.
While the scientists are carrying out their “studies” on the causal factor/s of CRF, it is extremely important that action is taken to reduce the occurrence of CRF. It is known that CRF is caused by a toxic elements/s or compounds in water. Hence, a method of detoxifying water needs to be developed. A few moths ago, Dr. U. Pethiyagoda, ( Ref. The Island 6th January 2011) has suggested the use of powdered dried seeds of murunga (Moringa oleifera) to purify water. The suitability of this method needs to be tested by an appropriate authority.
There is a need for a comprehensive public health effort to effectively address the problem of CRF. This should be taken as a National Priority with the main responsibility resting on the Ministry of Health. This ministry needs to implement an integrated programme in association with other responsible authorities, such as the Ministries of Science and Technology, Education, Water Resources to control the occurrence of CRF in the country , which is considered to be the third leading cause of death in North Central Province. If we wait till the scientists find the causal factor/s, thousands of people from the dry zone will have to face fatal effects.
Use of Rainwater for drinking is a good alternative, for rainwater collected properly has no toxic elements in it. Rainwater is relatively the most pure form of water. If collected and stored properly, it can be used for all domestic purposes including drinking. Out of the total amount of water a country receives in the form of rain, about 40% finally end up in the sea A considerable portion of the rainwater that falls on the roofs of buildings can be collected in tanks in the premises itself. Water that falls on a roof of 1,000 sq m in an area where the average annual rainfall is 2,000 mm, would be around 2,000 cubic meters (i.e 2 million liters or app. 400,000 gallons). Water thus collected would be free of toxic substances and could be used for numerous domestic purposes including drinking. For centuries the world has relied upon rainwater harvesting to supply water for households. Before city water systems were developed rainwater was collected (mostly from roofs) and stored in cisterns or storage tanks and used for drinking and other domestic purposes.
Bangladesh achieved a remarkable success by supplying 97 percent of the rural population with tubewell water but the system is on the verge of collapse due to the presence of arsenic in groundwater in excess of acceptabie limit. The population coverage by safe water supply has been greatly lowered by arsenic contamination and presently stands at around 75 percent. Provision of arsenic contamination free water is urgently required to mitigate arsenic toxicity and protection of health of the rural population in the arsenic affected areas. In this context, rainwater harvesting is being considered as a potential optionfor water supply in Bangladesh.
Bangladesh is a tropical country and receives heavy rainfall due to south-easterly winds during the rainy season. The average annual rainfall varies from 2200 to 2800 mm but 80 percent of the rainfall occurs during May to September. The unequal distribution of rainfall over the year needs rainwater reservoirs of good capacity for storage of rainwater in the rainy season to meet the water requirements in the dry periods. Again a suitable rainwater catchment is required for the collection of good quality rainwater in adequate quantity. The spatial and monthly rainfall distributions have been analysed. The storage volume and catchment area requirements in relation to rainfall intensity, family size and water consumption have been determined. The paper provides adequate guidelines for the development of a rainwater based water supply system in Bangladesh.
The presence of high arsenic in groundwater of Bangladesh is an emerging problem of great health concern. Millions of hand tubewells have water, which is not safe for drinking and cooking. Arsenic-free safe water supply to the affected communities is a great challenge.
Dhaka Community Hospital is implementing an arsenic mitigation project, where the development of alternative arsenic-free safe water options for the rural communities.
Dhaka, Community Hospital has constructed 20 Rainwater Harvester units considering rainwater as a good option for drinking and cooking. The problem is that it can be used only in the rainy season (only 3-4 months.)
DCH has converted the Rainwater Harvester into Rainwater Harvester cum Sand Filter unit to treat arsenic contaminated hand tubewell water. The same rainwater harvester unit may be used in two ways
• Rainwater Harvester- catching rainwater in the rainy season
• Rainwater Harvester cum Sand Filter- treating arsenic contaminated hand tube wellwater in the dry season.
The results of the arsenic treatment of the Rainwater Harvester cum Sand Filter are good. The concentration of arsenic in hand tubewells were 0.1 to 1.0 mg/l; after filter by the Rainwater Harvester cum Sand Filter unit the concentration of arsenic came down to 0.02-0.05 mg/l which is within the Bangladesh maximum permissible limit.
DCH has also tested the total and faecal coliform count of the filtered water and found it to be free from total and faecal coliform.
By modifying the construction of the rainwater harvesting unit into a rainwater harvester cum sand filter, people are able to use it throughout the whole year.
Chronic Renal Failure (CRF) is reported to have affected nearly 15,000 inhabitants among the farming community in North central Province of Sri Lanka.. According to the results of separate studies CRF is attributed to high levels of different constituents in drinking water. Among these constituents are cadmium, fluoride, aluminum, toxins released by Blue Green Algae, pesticides etc