Main Water Quality Problems from Surface Water Resources Perspectives - Case Study Example

Surface water resources, water quality and pollution problems Introduction Earth looks like a blue ball from the moon. This is because over 70% of the Earth’s surface is covered with water. Water is certainly the most valuable natural resource that exists on planet earth. Most of the Earth’s water is in the oceans (97 per cent) or locked away as ice. The largest volumes of freshwater are stored underground as groundwater, accounting for about 0.6 per cent of the total. Only a small portion (0.01 per cent) is present as fresh surface water in lakes, streams lochs, reservoirs, ponds, rivers canals, ditches, coastal waters and estuaries (Vale, 2006) . Unfortunately, it is the only proportion which is very important for humans and other terrestrial organisms. Groundwater is all water which is below the surface of the ground in the saturation zone (that is, below the water table) and in direct contact with the ground or subsoil (Bellamy, 2005). The quality of fresh water is vitally important. We depend on surface and groundwater sources for our drinking water. We also need water to generate energy, to grow our crops, to harvest fish, to run machinery, to carry wastes, to enhance the landscape and for other activities. We use water for washing and cleaning, industrial abstraction, recreation, cooking, gardening, as well as simply to enjoy it. Water is also vital as a habitat for both freshwater and marine plants and animals (Vale, 2006). Pollution of the surface water is one of the global concerns. Though we recognize the fact that water is the most important natural resource, we pay no attention to it by polluting it. Almost any solid, liquid or gaseous substance entering surface waters could be classified as a pollutant. This includes chemicals, salt, wash waters, waste products, trade effluents, and fuels. As a result, we are slowly but certainly harming the planet to the point where organisms are dying at a very alarming rate.  In order to combat water pollution, it is essential that we understand the problems and become part of the solution. Sources of surface water pollution Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water.  When it is unfit for its intended use, water is considered polluted.  There are two sources of pollution: ‘point’ source pollution, that are discharges from a specific location (pipe, drainage ditch etc) and ‘non-point’ pollution that emit from diffuse sources, such as run-off from agricultural land. Point sources of pollution occur when harmful substances are emitted directly into a body of water.  The Exxon Valdez oil spill best illustrates point source water pollution.  A non-point source delivers pollutants indirectly through environmental changes.  An example of this type of water pollution is when fertilizer from a field is carried into a stream by rain, in the form of run-off which in turn affects aquatic life.  While there are technology for point sources of pollution to be monitored and regulated, non-point sources are much more difficult to controlled and monitored.  Pollution arising from non-point sources accounts for a majority of the contaminants in streams and lakes (Krantz and Kifferstein, N.D.). Nutrients The main polluting nutrients in relation to water are nitrogen, ammonia (a form of nitrogen) and sulphur. They arise from the natural breakdown of crop residues and soil organic matter, rainfall, fertilizers, urine and manure, silage, landfill sites, wastewater and industrial effluents, power generation and other fuel-burning activities. In excess levels, nutrients over stimulate the growth of aquatic plants and algae.  Excessive growth of these types of organisms clogs the waterways, use up dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water. Nutrients are the principal cause of eutrophication which is the enrichment of lakes, rivers and the marine environment leading to increased plant growth and the occurrence of algae. Excessive plant growth can also increase the pH (acidity) of water through the removal of carbon dioxide by plants and algae during photosynthesis. These changes in the oxygen status and acidity of water will affect the type and diversity of plants and animals that can survive. Eutrophication can lead to quality problems associated with water abstracted for drinking water giving rise to increased treatment costs. It can also have an impact on recreational uses of rivers and lakes, such as angling and sailing, by affecting the status of fisheries and reducing the aesthetic quality of the water body. Pesticides These are harmful chemical which include herbicides, insecticides and fungicides. These are mainly used in gardens, in agriculture, in roadside and trackside (railway) maintenance, and in parkland and golf courses. The agricultural runoff pollutes the streams and rivers and results in bioaccumulation and contamination of aquatic organisms. Heavy metals Heavy metals are widely-used ingredients for chemical compounds used in industry. Industrial contaminated land can be a source of heavy metals leaching into the environment. They also exist naturally in soils at low concentrations. They can be found in fuel, chemicals, waste materials and batteries. In high concentrations they are toxic to humans, animals and plants. Suspended solids Suspended solids are mineral and organic particles that remain suspended in water. They sink only very slowly or are easily re-suspended by water turbulence. Suspended solids might be eroded soil or decayed leaves. Wastewater from sewage works and industry might also carry suspended solids into water bodies. Suspended solids cause water to be turbid and this cloudiness reduces light levels. Turbidity can also be a sign of other pollution since nutrients, pesticides and metals can be attached to the suspended particles. Pathogens Pathogens are another type of pollution that proves very harmful.  These are present in excreta from human and animal sources. They can enter water through poor wastewater management or poor handling of manures, slurry and other farm wastes. They may also be carried directly off fields by heavy rainfall or enter water bodies where stock and wildlife have direct access for drinking purposes. They can cause many illnesses that range from typhoid and dysentery to minor respiratory and skin diseases.  Pathogens include such organisms as bacteria, viruses, and protozoan.  These pollutants enter waterways through untreated sewage, storm drains, septic tanks, runoff from farms, and particularly boats that dump sewage.  Though microscopic, these pollutants have a tremendous effect evidenced by their ability to cause sickness. Hydrocarbons and Persistent organic pollutants (POPs) These include vegetable and mineral oils (including petrol, diesel, white spirit, heating and lubricating oil), and chlorinated solvents such as dry cleaning fluids. POPs are chemicals that are capable of long-range transport, accumulate in human and animal tissue, and have a significant impact on human health and the environment, even at low concentrations. They include such substances as dioxin and PCBs. Petroleum often pollutes water-bodies in the form of oil, resulting from oil spills.  The previously mentioned Exxon Valdez is an example of this type of water pollution.  These large-scale accidental discharges of petroleum are an important cause of pollution along shore lines.  Besides the supertankers, off-shore drilling operations contribute a large share of pollution.  One estimate is that one ton of oil is spilled for every million tons of oil transported.  This is equal to about 0.0001 percent. Radioactive substances Radioactive substances are produced in the form of waste from nuclear power plants, and from the industrial, medical, and scientific use of radioactive materials.  Specific forms of waste are uranium and thorium mining and refining.  These are extremely hazardous to the aquatic organisms. Temperature The last form of water pollution is heat.  Treated effluent from industry and sewage treatment works is generally warmer than the receiving waters into which they are discharged. Heat is a pollutant because increased temperatures result in the deaths of many aquatic organisms.  These decreases in temperatures are caused when a discharge of cooling water by factories and power plants occurs. Since warm water carries less oxygen than cold water, this can cause temperature stress as well as stress due to reduced oxygen in the water (Water Framework Directive, 2005). Water quality and pollution problems in UK Studies show that only 15 per cent of the UKs 150,000 miles of freshwater channels remain in a "natural condition" with the remainder dredged and converted into drainage ditches, straightened and canalized for navigation, or constrained by hard, lifeless banks. Only one acre in 40 of the flood-plain wetlands that once spread over our river valleys has survived centuries of drainage for intensive farming and urban development. One in three UK rivers is colonized by alien plants, and pollution is widespread, from sewage works and factories and poor agricultural practice (Tickell, 1999). The increased intensification of farm production on the one hand together with the steps taken to reduce point source pollution from factories and sewage works on the other means that, as the Policy Commission on Food and Farming January 2002 noted, agriculture is now a major polluter of water in UK. Nitrate levels in many English waters, both ground and surface waters, are increasing. Nitrate pollution is of concern because it has to be removed before water can be supplied to consumers, and it can harm the water environment. Over 70% of nitrate and 50% of phosphates enters water from agricultural land in UK. Up to a half of Englands bathing waters are affected by short term contamination by agricultural pollution, mainly by microbes from livestock manure being washed off farm land after rain. The majority of silt loads to English rivers and lakes are derived from heavy soil erosion from agricultural land. This alters the composition of gravel sediments, reducing water clarity and causing serious problems for fish, plants and insects. Pesticides are contaminating drinking water sources, requiring expensive additional treatment at water works to remove pesticides before this water can be supplied to consumers (Department for Environment, Food and Rural Affairs, 2004). Agriculture is not the only source of diffuse water pollution; urban, transport and construction activities are all sources of pollution which affect the ecology and water quality of many catchments. Run off from transport, on street activities such as car washing, discharges from contaminated land and herbicides from fish farming all contribute to diffuse pollution. Elevated levels of nutrients can result in toxic algal blooms that affect natural aquatic ecosystems. A recent estimate of the total external environmental costs of agriculture in the UK was £2.3 billion in 1996. The approximate annual costs in the UK of treating drinking water for pesticides are about £120 million, for phosphate and soil about £55 million, for nitrate around £16 million and for micro-organisms around £23 million. Besides for monitoring water supplies and supplying advice on pesticides and nutrients costs around £11 million; and off-site damage from soil erosion is put at £14 million (Mersey Basin Campaign, N.D.). Almost all (over 99 per cent) of the population of England and Wales is served by the public water supply, of which, 67 per cent comes from surface water sources and 33 per cent comes from groundwater sources (Department for Environment, Food and Rural Affairs, 2004). Conclusion Water pollution and its impact is a global issue. The problems associated with water pollution have the capabilities to disrupt life on our planet to a great extent. There are several laws to combat water pollution thus acknowledging the fact that water pollution is, indeed, a serious issue. But the government alone cannot solve the entire problem.  It is the responsibility of each individual to protect local water resources. It is essential to preserve existing trees and plant new trees and shrubs to help prevent soil erosion and promote infiltration of water into the soil.  Awareness and education will most assuredly continue to be the two most important ways to prevent water pollution.  If these measures are not taken and water pollution continues, life on earth will suffer severely. References Vale, J., (2006). Water Quality, The Environment Agency, Retrieved January 3, 2006, from http://www.environment-agency.gov.uk/subjects/waterquality Bellamy, G., (2005). Pollution of Surface Waters and Groundwater, Retrieved January 3, 2006, from http://www.netregs.gov.uk/netregs/275207/275475/ Krantz, D. and Kifferstein, B. (N.D.). Water Pollution and Society. Retrieved January 3, 2006, from http://www.umich.edu/~gs265/society/waterpollution.htm Water Framework Directive, (2005). Source of Pollution – Overview. Retrieved January 3, 2006, from http://www.euwfd.com/html/source_of_pollution_-_overview.html Tickell, O., (1999). WWF report Living Rivers 1999, quoted in Half of Europes freshwater habitats ruined October 1999. Department for Environment, Food and Rural Affairs (DEFRA), (2004). NITRATES - Reducing Water Pollution from Agriculture. Retrieved January 3, 2006, from http://www.defra.gov.uk/environment/water/quality/nitrate/default.htm Mersey Basin Campaign, (N.D.). Diffuse Pollution. Retrieved January 3, 2006, from www.merseybasin.org.uk/information.asp?page=1&pagesize=5&confirmed=1&id=0&docid=66 Read More