Water Quality Pollution

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Question one: Potential sources of pollution and their potential impact on human health and environment.

The Bevern River in Wales has for many years been clean and free from pollution. However in the recent years it have faced different threats of pollution that have posed risk to the water environment and the existence of the several fish species living in it. The major potential source of pollution to the Bevern stream is the sewage system that runs along the Bevern stream the inspection chambers between the Barcombe and the Barcombe sewage treatment work overflow sometimes and the waste are directed to the stream. The overflow has made the levels of the E. coli to rise above the normal required amount in such a stream. The feaces also contain a lot of ammonia and has therefore increased the amount of the dissolved Nitrogen and phosphates.

The surrounding that is also polluted with the sewage wastes has also raised a concern over pollution in the stream. The waste is washed down the stream during rain season and the problem of pollution therefore continues. In September 2007, the problem of serious pollution was encountered in the Bevern stream when the raw sewage burst into the stream.

The raw sewage has more health and environmental effects than the treated sewage and during the leak of the raw wastes into the river; the water quality was adversely affected. (Lorna, and Jamie, 2001)

The dangers that are associated with the problem of pollution are serious. The pollutant cause the rise of the E. coli and amount of the dissolved phosphates and Nitrates that also reduce the amount of Dissolved Oxygen in the water that can affect the life of the species living in the waters that cannot cope with low oxygen.

The problem of overflow of the Inspection chamber was solved but the danger still remains as the as the walls of the river near the chamber are weak and with the slightest rain, they can still burst and overflow.

Bevern stream drains its water to Sussex River Ouse whose tributaries are at risk from the pollution of the several sewage treatment plants that drain the sewage waste to these streams. As a result, the Sussex river remain threatened to pollution from these treatment plants that have very low standards according to the river Sussex Conservation Society and other societies.

The often breakdown of the infrastructure around the Bevern stream is also a potential source of water pollution in the stream.

The presence of high levels of E. coli and low dissolved oxygen can lead to the death of the fish species in the water. The pollution of the water with Nitrates and Phosphates is also dangerous as it can lead to the growth of harmful water plants that can cause effect to the vertebrates in the river and can also reduce the rate of floe of the river that can also affect the amount of Dissolved Oxygen.

The solid wastes from Wales community neighboring the stream also block the flow of water in the Bevern stream, the solid wastes also increase sediments in the river that affect the movement of the vertebrates hence lack food and die. They also destroy the breeding sites which has adversely reduced the number of species in the water.

The consumption of this polluted water can be dangerous to human health as they cause Typhoid from the E. Coli bacteria present in the water from the sewage wastes.

Question Two: The limitations to obtaining data on water quality that accurately reflects the changing conditions in the stream.

The collection of data on the quality of water in Bevern stream is not efficient and reliable. The problem of collecting data is associated with the changing in the fauna and flora in the stream, at the mouth of the where the tributary Bevern joins River Sussex, there are several species of vertebrates which are as a result of low level of pollution at the site while in the lower mainstream of the river, there are less species as they die from the immediate sewage pollution from the Barcombe sewage treatment section. If samples of the water are taken from these two points of the stream, there will be a great difference in the results that cannot be relied for the real water quality changes currently experienced in the river. Several snail species that are not capable of surviving in low dissolved Oxygen die at some point of the stream as well as nymph. (Duncan, and Horan, 2003) This is from the increase in the level of the phosphates and ammonia level in the water.

There is a greater difference in the quality of water at different points of the river, the data collected therefore should not be limited to few samples and should include several samples from different points. The analysis carried out on the water should be used to look for an average so that the water quality results can be compared to the European Community Fresh Water Fish Directive.

The other limitation that can also emerge from the data is from the capability of different vertebrates and other species to survive in different water quality. Some can survive in low dissolved Oxygen while some like fish cannot. The PH of the water may also not be fit for some animal species but can favor some. Therefore it is very unreliable to collect data at the stream based on some factors. The stream should be upgraded to the salmonid water quality standards which are rigorous than the EC standards. The Bevern water quality deteriorates downstream as a result of the treated sewage discharge into the stream Dichling which is closer to the sewage discharge. The effect on the quality of water also depends on the season, for example during the dry summer seasons; the stream water quality is very poor as compare to the winter.

The standards are compared for two fish species, the Salmonid and the Cyprinid in which the former is delicate and need extremely high quality water. (Lorna, and Jamie, 2001)

Question Three: Outline what the results for nutrient levels (e.g., ammonia, nitrate and phosphates) tell you about the trophic status of the stream.

Trophic status of a water body is defined in relation to the concentration of nitrogen and phosphorus nutrients present in the water as well as the algae. These two nutrients are the key determinants of the trophic status which is the biological fertility or productivity of the water body. The levels of the three nutrients in the Bevern stream are significantly higher than the standard EC Fisheries directives for both the Salmonid and Cyprinid species. (Crompton, 2002) This indicates that the stream is relatively productive which is the reason why the stream has a lot of plants growing in it as well as algae in the water. These plants provide food for the different vertebrates in the water that result to breeding and increase in the number of species in the stream. The nymph in the stream eats the algae. The fish feed on these small invertebrates and from their waste they add the amount of Ammonia and phosphates in the water. The balance between the levels of these nutrients is maintained through the different trophic levels.

Treated sewage discharge from Barcombe treatment section into the stream help to increase the levels of these nutrients. The high level of Dissolved Oxygen is also favorable for the increment of the fertility of the stream that increases productivity. The DO in the stream is very high as compared to the set EC standards for dissolved oxygen as seen from the table above. Oxygen favors the development of algae and other water plants. The availability of these plants is a ready source of food to some species. This result to the increase in number of this species which form food for the fish and other vertebrates. The trophic status of the Bevern stream is reasonably high and the future increase in the number of species is possible as long as pollution is controlled.

Bavern stream fresh water aquatic environment studies showed that at the mouth of river Sussex, there are several species of fish that exist as a result of the trophic status in the stream. The problem of pollution in the stream has been sought by the Environmental Agency and this has assisted in the improvement and maintenance of good trophic status in the stream.

Question Four: What do the bacteriological data tell you about levels and sources of faecal pollution in the Bevern stream?

The level of the Escherichia coli is 64000 per 100ml and the Entercoli is 32000 per 100ml. These values are very high in the stream which shows that there is faecal pollution in the stream. The faecal pollution is from the sewage discharge from the treatment works along the stream. The are also possibilities of untreated sewage discharge into the stream that has caused in the high level of the Enterococci which is a colony of the intestinal coli in water. The levels are triggered by the leakage of the September incident where the sewage over flew into the river.

The surrounding area may also be producing faecal pollution into the stream. The animal faeces in the nearby forest is responsible for the intestinal coli in the stream which are very high.

Generally the water quality in Bevern stream is good and favorable for aquatic biodiversity as the level of Dissolved Oxygen and the ammonia and phosphate nutrients are high. The E. coli is high which is dangerous to the health of the people living around the stream. (Crompton, 2002) The faecal pollution is a major source of the waterborne diseases that affect the community living around. The sources of the faecal pollution are many and cannot be avoided unless the level of treatment for the sewage discharged in the stream is raised to better standards.

The biological data shows that the stream is more polluted with the faecal wastes from both the treated sewage and the surrounding area which is also potential source of faecal pollution for the Bevern stream.

The intestinal coli is a guarantee that their must be some direct disposal of feaces into the stream without treatment or there is discharge of raw sewage into the stream. This also shows that there are infected people around with the E. coli bacteria that cause Typhoid, Dysentery or Diarrhea in human beings. However it has not been proved that water shrew faeces are present in the stream. The current research that is being conducted by the Sussex Conservation Society is underway where plastic tubes are set near the water with muslin bait at one end, the shrews will enter in the tube to feed on this delicacy. If they are found then the faecal wastes will be too high which will have attracted the faecal shrews. (www.sussex-ouse.org.uk/research/index.htm)


Crompton, R. (2000). Determination of Organic Compound in Water, (New York, Mac Graw Hill)

Lorna, F. and Jamie, B. (2001). Water Quality, Guidelines, Quality and Health, (London, MacMillan)

Joseph, A. (2004). Waterborne Zoonoses, (London, MacMillan)

Mason, F. (2002). Biology of Freshwater, (New York, Wesley)

Duncan, D. and Horan, J. (2003). Water and Wastewater Microbiology, (London, Oxford University Press)

Bull, T. and Marrs, L. (1998). Biotechnology for Clean Industrial Products and Processes, (London, Oxford University Press)

Kavanagh, D. (2006). A Country Pillow Book, (London, Cambridge University Press)

Information on the Bevern Stream also available from www.sussex.org.uk (Retrieved on 15th April, 2008)