Water Pollution In Rural Areas Environmental Sciences Essay

Water is a vital commodity and is essential to the natural environment. We not only rely on it for drinking but also for its use in industrial processes, cooking, cleaning and the growing of our food. There are many sources of water pollution the major sources of water pollution being; runoff, agricultural pollution, urban stormwater, organic matter, toxic waste, and thermal pollution (The Environment Agency 2010). These types of pollution tend to be area specific (for example agricultural runoff will on the whole come from rural areas as that’s were most farms are situated) although this is not always the case, any type of water pollution could occur in any area rural or urban. Rural and urban areas both have many contrasting sources of pollution, all of which will have varying affects on the surrounding environment and its habitants.

Although the environment which makes up Urban and rural areas can be vastly different they can at the same time be affected by the same environmental problems relating to water pollution. One example of this is eutrophication of waterways both rural and urban. Eutrophication is a situation when foreign bodies such as fertilizers of sewage enter a river or stream and act as a nutrient for algae causing rapid growth and algal blooms (May & Sivakumar 2009). These algae grow out of control and thus the water becomes depleted in oxygen. The water becomes depleted in oxygen because dead algae sink to the river bed the retrieve the oxygen so it can decompose. This can then lead to further problems if too much algae decomposes it may use all the oxygen. This will mean all the oxygen has gone and because the water near the surface of the water is warmer its oxygen doesn’t mix with water from the bottom as it’s colder and has a higher density .This eutrophication of a water body can occur in both rural and urban areas. In an urban area this problem arises primarily from sewage treatment works, if a works has an increased amount of sewage to treat then there may be some secondary or direct discharge that may enter the water supply thus causing Eutrophication (Neal et al, .2010). A similar problem can occur when leaks of phosphorus from septic tanks discharges into a local river system (Neal et al,.2010) although this isn’t tied down to either rural or urban areas .This is also very likely to occur in rural areas where agriculture is more prominent and the uses of fertilizers are increased. Particularly in the following practices of cereal production, maize, potato and dairy production where fertilizers are heavily used or large amount of manure needs to be recycled. (Jarvie et.al 2009)

One of the biggest problems which can lead to the pollution of urban waterways is runoff. Runoff is also a major cause for concern in more rural areas and areas of intense agriculture. The problem of runoff in urban areas however is contrasting to rural agricultural runoff. In the sense that runoff in urban areas arises from garden fertilizers, pesticides, anti-icing chemicals, vehicle emissions and pet waste. These pollutants are both organic and inorganic and can also be perversely complex, this leads to little knowledge of how these pollutants will interact once they combine and enter a water body. Due to the little knowledge of these interactions it makes it increasingly difficult for an amount allowable discharged concentration to be devised (Kuhl et.al 2010). These pollutants runoff into any local water system via tarmac or pavement areas and because of the increase in tarmac and concrete roads and driveways it makes this pollution easier to reach the water. This non permeable surface which is found more so in urban areas not only makes it easier for any pollutants to travel into water systems , but it also increases the risk of flooding and the risk of storm water moving sewage into freshwater. In rural areas this isn’t such a prevalent problem as most rural areas are permeable. Although because of this it makes the control and identification of runoff in rural areas much more difficult to locate. Runoff in rural areas is usually linked to agricultural runoff. This is categorized as nonpoint-source pollution because the pollutants involved originate over larger areas and the entry of this pollution into waterways cannot be pin pointed precisely (which is not the case for some sources of urban pollution). As this rural agricultural runoff is nonpoint-source it means any treatment of pollutants entering any water system is almost impossible, although agricultural runoff can be supervised in other ways such as farmers minimizing fertilizer use and the correct disposal of animal waste and fertrilizers. However there is another type of pollution Point source which is where pollution will enter a water system in a specific point (such as a sewage pipe). These point sources of pollution are more often found in urban areas where there may be a sewage treatment plants are normally located. This type of point source pollution makes any control or treatment of pollution much easier as it is located in one area and not spread over larger areas as agricultural runoff sometimes can be.

Urban stormwater is a major source of pollution to any water bodies. It arises from when rainwater washes over any impermeable urban area picking up with it toxic chemicals, vehicle emissions, sewage, household waste etc. The problem of urban storm water becomes exacerbated when extremely heavy rainfall occurs and the flushing water can erode stream banks and streambeds. This stormwater will then be moved downstream along with any eroded soil into any waterbodys, this sediment will then sink to the bottom of a water body. This can do damage to aquatic environment and can even destroy fish eggs. Excessive sediment in a water body can damage aquatic life in other ways. It can increase risk of disease, damage fish gills and also because of thick layer of sediment will cause darker conditions it may block enough light to limit growth of aquatic plants which is essential along with oxygen to aquatic life. As well as sediment from eroded soil urban stormwater can also pick up metals from the urban environment, the main source of which is from vehicle emissions in urban environments. Some examples of the types of metals usually found in urban stormwater are Lead, cadmium, zinc, mercury, iron, nickel and copper. All of which have differing affects including damage to fish gills and death of aquatic organisms. These metals will accumulate on roadways and then be washed off in rainwater into the water bodies. In smaller amounts metals can derive from other sources such as metal roof tops which are pelted from heavy rain, some weed killers contain zinc and also scrap yards which keep metal outside.

Unlike most sources of urban water pollution rural sources normally come in the form of diffuse pollution. One of the mains sources of which is agriculture as previously mentioned, the main pollutants involved in diffuse water pollution in agriculture are nitrogen and phosphorus. Phosphorus and nitrogen are both essential in term of animal and plant growth. Phosphorus and nitrogen are found in a variety of different sources. Animal waste as found in areas of agriculture, also the use of phosphorus and nitrogen in fertilizers contributes to water pollution. The adding of fertilizers to crops also returns the essential phosphorus back to the soil, which gets taken from the soil to help grow the crops to start with. Phosphorus can also be found in soils in both the organic and inorganic form. In terms of organic phosphorus it exists in plant residues, organic soil and microbes. Phosphorus can also be in an insoluble form within soil meaning that plants cannot take in this phosphorus. When fertilizers are applied that contain phosphorus as soluble compounds most of the phosphorus will be absorbed into the soil which can then be washed on directly into a body of water, leading to eutrophication. This introduction of nitrogen can seriously affect the balance of the natural nitrogen cycle. Nitrogen is essential nutrient for plant growth and part of a natural cycle that occurs which if perturbed can have serious effects on organisms that rely on the cycle. As shows in figure 1 the addition of extra nitrogen from farming practices and the use of fertilizers will lead to the potential eutrophication of water bodies. This is due to the when the balance of the nitrogen cycle is interrupted with the addition of nitrogen from fertilizers. As a result of this the natural nitrogen cycle expels the surplus nitrogen which can be washed away into a water body.

Figure 1 – Nitrogen cycle diagram (source:http://www.physicalgeography.net/fundamentals/9s.html)

Although not a major source of water pollution Mining still can influence water bodies. Mines are normally found in more rural areas although they can be found in urban areas, as in earlier time small towns would have been built around these sources of coal and iron ore .Mining’s primary source of water pollution comes from acid drainage in mine systems. This happens when the contents of a mine (coal or metal ore) oxidise on contact with air to create sulphuric acid. This problem of mine drainage is more of a problem generally in closed mines. This is because water which may have previously been blocked or stopped somehow from entering can now enter washing the acidic solution with it. As well as containing sulphuric acid the washout from the mines may also contain high concentrations of sulphur, heavy metals and iron. When this mine drainage enters a water body the change in pH from acid to a more neutral pH causes the iron to precipitate as ferric hydroxide. This will settle to the bottom of a water body which will deplete the water of oxygen thus seriously harming aquatic life.

Mining can be mainly described as a rural source of water pollution whereas one source can be described as the opposite. Land fills sites are growing and growing in the United Kingdom and many land fills are situated in urban areas as they tend to bill filled with waste from nearby towns and city’s. Land fills are a potentials source of water pollution as when it rains when waste is being deposited the rainwater will pass through the waste picking up along the way all the pollutants such as heavy metals, ammonia and oxygen depleting pollutants which if they reached the water bodies could seriously harm any aquatic life. Also the waste itself in whatever from this may come in as will contain water and as the waste degrades in the landfill this water will be released which will also carry the pollutants into the soil, which may eventually end up in a water body. These problems will all be more prevalent with older land will sites as new land fills have measure in place to reduce the risk of water pollution from these sites.

In conclusion both rural and urban areas have a number of different sources of water pollution. Although there are some very different sources such as mine drainage in rural areas which causes acids and heavy metals to enter water body whereas in urban areas land fill sites can cause pollutants such as ammonia to enter water systems. One common source that both rural and urban areas share is runoff. Although both share this source of pollution they do both differ slightly. Rural areas will tend to have agricultural runoff where nitrogen and phosphorus are the common pollutants which as a result cause eutrophication. Whereas urban areas also encounter the pollution problem of runoff but in term of the pollutants involved it varies significantly to rural runoff. Urban stormwater which is the urban runoff differs to agricultural runoff because it can pick up many more types of pollutants such as heavy metals, oils and other vehicle related emissions, sewage, household waste and like rural runoff it also can pick up fertilizers from gardens. This urban stormwater can be considerably worse in terms of the impacts on aquatic organisms than agricultural runoff because of types of pollutant that are involved. It is also important to remember that because agricultural pollution is diffuse or non-point source pollution as previously mentioned this makes the treatment or control or agricultural runoff much more difficult than the control or treatment of point sources of pollution such as urban sewage leaks.