Agricultural Pollution In The United Kingdom Environmental Sciences Essay

The global human population doubled from less than 3000 million to 6000 million during the latter half of the twentieth century. The demand for food increased as the global population increased. This resulted in the intensification of agriculture to meet the higher food demand which placed an increasing demand on the natural environment. This has lead to the United Kingdom now having more than 76% of land being used for agricultural production. Since the 1930s the UK agriculture industry has undergone a major revelation. The productivity levels have considerably increases due the progress in crop and animal breeding, the accessibility of pesticides and fertilisers and the fast and advancing technology. [1] 

The move to more intensive farming methods has led to a marked increase in the amount of pollution incidents recorded (Pollution can be described as the unwanted environmental effects of human activity) .Figure 1 show that the pollution incident levels are constantly changing, this if reflected by the dynamic moves and the progress the agriculture industry make.

Fig 1 taken from : G. Merrington , l . Winder, R. Parkinson, and M. Reedman , Agricultural Pollution: Problems and Practical Solutions, Taylor & Francis, 2002.

Agricultural processes can pollute in many ways, these include; deliberate pollution (the introduction of pesticides, fertilisers, genetically modified crops and sewage sludge into the environment). Agricultural processes and wastes (silage effluent and live stock waste) and the enhancement of natural processes from agulcultural activity (increased nitrous oxide emissions and soil erosion).

Fertilisers can cause problems in agriculture. Fertilisers are used in agriculture to promote plant growth. Fertilizers are combinations of the nutrients that plants must have to grow, in a form they can use. Fertilisers are used because as plants grow, they absorb and deplete nutrients from the soil. Farmer’s harvest those same nutrients when they harvest crops meaning the nutrients that are need are lost and need to be reapplied in order to achieve a successful crop year after year if crops are to be grown and harvested continually. [2] 

If the applied fertilisers or raw sewage ends up reaching rivers and lakes, they increase the levels of nitrate and phosphate them. This causes Eutrophication and can end up in the mass death of organisms in the water. The steps of Eutrophication are as follows; the growth of algae and other plants is increased due to higher levels of nitrates and phosphates that have entered the water. These form algal blooms and mean there are a larger than usual amount of producers and they become overcrowded and being to die quicker than they are consumed. The dead producer’s provider food (energy) for the decomposers. This causes the amount of decomposers to increase quickly and they use up large amounts of the oxygen in the water. This increases its biological oxygen demand (BOD) and this change causes a lack of oxygen in the water and leads to the death of aerobic organisms. In cases with raw sewage, which is full of bacteria, the BOD is even greater. [3] Also if Ammonia (90% of ammonia emissions in the UK is from agriculture [4] ), pesticides, oil, degreasing agents, metals and other toxins from farm equipment ends up in rivers and lakes they can harm and kill aquatic life. They can also cause health problems when they get into drinking water.

Agriculture is one of the biggest causes of water pollution in the UK (see figure 2) and in 2001 had the second largest water pollution incidents from a range of economic sectors.

Fig 2 taken from : G. Merrington , l . Winder, R. Parkinson, and M. Reedman , Agricultural Pollution: Problems and Practical Solutions, Taylor & Francis, 2002.

Organic waste is another big polluter from agriculture. Although the number of pollution incidents due to organic wastes is declining in the UK, the Environment Agency spends approximately £5 million pound per year on river pollution incidents caused by agriculture. This is because the production, storage and disposal of animal wastes (pigs, cows) and silage effluent present major risks to streams and rivers including the aquatic life. A result of the intensification of livestock production in the UK has caused a large increase in the amount water pollution incidents as a result organic wastes. 90% of all farm pollution incidents are a result of organic pollutants.

Incidents are mainly in areas that have a high livestock production. In the UK the highest water pollution incident occur in the south west, midlands and west of the country.

Gaseous emissions from UK agriculture are responsible for approximately 8% of all greenhouse gas emissions. Nitrous oxide and methane are two of the biggest polluters from agriculture with over 50% of nitrous oxide resulting from agricultural activities and 37% of methane emissions in the UK from agriculture. The causes of Nitrous oxide to be released into the atmosphere in agriculture are during the application of nitrogen fertilisers. The effects of Nitrous oxide are global and include the ‘eroding’ of the earth’s ozone layer (which can cause problems including an increase in the risk of skin cancer) and causes the greenhouse gas effect. The greenhouse gas effect is the heating of the surface of the earth due to the presence of an atmosphere containing gases that absorb and emit infrared radiation. [5] 

Nitrates from fertilisers can also soak into the ground and eventually end up in drinking water. This is dangerous and can cause health problems such as methemeglopbinemia or blue baby syndrome which causes death in infants. [6] 

The cause of Methane release in to the atmosphere in agriculture is mainly due to livestock, most commonly from ruminants due to enteric fermentation. Enteric fermentation is fermentation that takes place in the digestive systems of ruminant animals. Both nitrous oxide and methane both have a high global warming potential, methane can absorb 21 times more infrared radiation than carbon dioxide and is an important greenhouse gas.

Carbon dioxide emission from agriculture can come from a number of sources, whether it from fossil fuel combustion or land change. The use of fossil fuel production in agriculture is wide spread, whether it’s direct from farming machinery or from the transport of goods from the farms to other company or to the supermarkets. However, there is more carbon in the world’s soil than in the atmosphere and plant biomass put together. This means that land use change intended for greater production can increase the amount of carbon dioxide being released. The turnover of biomass and land change responsible for 5% of the total carbon dioxide emissions alone in the UK. The loss of soil carbon due as a result of degradation of land is also another contributor to carbon dioxide due to agriculture. Soil is an important carbon sink and acts as a transfer store for carbon. Agricultural practices that reduce soil carbon levels by methods that degrade organic matter reduce the capacity of the of the carbon sink. The release of carbon dioxide can have a global effect as carbon dioxide is the most important greenhouse gas and is a big contributor to the greenhouse effect. The reduction in soil also causes a reduction in the infiltration rate, this increases soil run off and erosion which can lead to the deposition of sediment onto roads and into drains, this can also cause damage to the quality of water in lakes and rivers due to an excess inputs of chemicals and other substances. The increased run off and sedimentation can cause a greater risk of flooding further downstream. [7] The effect of carbon solubility in water also means exchanges of carbon can occur in the world’s oceans causing a wider spread effect. Changes in carbon between the atmosphere and land are dynamic and can be shown in the carbon cycle (figure 3). Figure 3 show the carbon cycle of a farm. Changing the inputs and outputs, or removing stores can drastically change the amount of carbon in the atmosphere or in the land.

Figure 3 taken from http://www.farmingfutures.org.uk/Images/Carbon-Cycle-2306.gif

Pesticides (including herbicides, insecticides and fungersides) are another pollutant from agriculture that can cause problems for the environment. Pesticides use has become an integral part of modern farming in the UK, with most crops having at least one and usually many more applications, with Cereal crop being sprayed around six times on average in the UK. More expensive crops such as vegetables and fruit can be sprayed over 15 times. The crops are sprayed to kill organisms such as pests, diseases and weed as they are unwanted in agriculture production as they would lower yield size. [8] However pesticides can cause point source or diffuse pollution in a number of ways. Pesticides can cause direct contamination of ground and surface waters. They can contaminate soil and leach into ground and surface waters. Pesticides also disrupt food chain and food webs as they can affect non-target organisms, whether by direct contamination or by accumulating further down the food web. This is a high occurrence as less than 0.1% of pesticides reach there target organism. [9] 

The movement of pollutants between the land, water and atmosphere can be summarised in figure 4. Figure 4 shows the relationship between pollution coming from a farm and the cycle it takes between the land, water and atmosphere .The pollutants could come from a number of the sources and examples that have been mentioned.

Figure 4 taken from http://www.ecifm.rdg.ac.uk/farm_waste.htm original by R. Cook 2000.

The effects of the agriculture pollution may be accounted for in two ways by the assignment of monetary value. The cost may be financial, for example incurred in water treatment or economic for instance due to the loss of a landscape feature valued by people which can be classed as visual pollution.

The cost of agricultural in the UK is high and in 1996 the total external cost of UK agriculture was £2343 million (range for 1990-1996: £1149- £3907 million). This is the equivalent to £208 per hectare of arable and permanent pasture. Significant costs occur from pollution due to agriculture, whether direct from point source pollution or from non point source pollution costs in the UK include; the contamination of drinking water with pesticides (£120 million per year), from emission of gases (£1113 million per year), soil erosion (£106 million per year) and food poisoning (£169 million per year), from damage to wildlife, habitats, hedgerows and dry stone walls (visual pollution) (125 million per year). [10] 

Pollution control and solutions should take into account the external cost or externalities caused by economic activity. For example a side effect or by product of agricultural practice which is unpriced within the farming economy may be incurring a cost for someone else by reducing their profits or welfare. [11] 

Solutions to agricultural pollution can include; Government action through changes in policy and law; this could mean that farmers are forced to cut down the pollution they are causing. Research and development, including training and information programs and economic instruments such as financial subsidies and taxes could help reduce pollution, as alternative methods of farming that pollute less may be offered to the farmers with money incentives, while heavy polluting techniques and methods may be taxed.

Other methods can include the modification behaviour by farmers, including changes in the use of agrochemical inputs, and other farm management practices.

Practical solutions too many pollutants can be achieved through good agricultural practice (GAP). GAP is a well established approach in Morden farming to reduce environmental pollution and is supported with national and international legislations. The UK has published guidelines on pesticide usage which along with GAP is intended to both minimise their impact on the environment and allow safer usage.

Practical solutions regarding gaseous emissions in agriculture are controlled with the support of legislation such as the Kyoto Protocol, which the European Union is committed to reduce carbon dioxide emissions. The UK is looking to reduce the level of emissions in 1990 by 12.5% before 2012. [12] To achieve this reduction the UK will need to cut its carbon dioxide in most of the economic sectors including agriculture.

Pollution management can be achieved in two ways. An attempt to ‘cure’ the problem by acting against the pollutants themselves, for example water treatment, or by preventing the cause of the pollution by encouraging alternative agricultural practices that are less polluting such as organic farming. Organic farming would reduce the number of pollution incidents due to agrochemicals, for example pesticides, including insecticides, herbicides, and fungicides [13] . However many farmer may be apposed to a move in organic farming, as it may result with a decreases yield of crop and an increase in labour outputs. A move to organic products may also reduce the target market for the food buyers, as higher labour and growing costs general mean the final product is more expensive than intensively grow products. This could limit the number of buyers this could result in a significant reduction in profit.

In conclusion pollution can arise from agriculture in a number of ways. The effects of the pollution can vary drastically, from affecting only a small localised area through point source pollution such as a single farm, or by having a wider effect, sometimes on a global scale, such as non point source pollution. The pollution from agriculture can also effect both the environment, including the animals and nearby residents, but also the economy.

Reducing pollution in agriculture can be difficult and have knock-on effects on both the environment and the economy. Many farming techniques rely on high polluting intensive farming methods to simply meet the demand of the population. Methods like these can be degrading to the environment, but vital for the farming economy to survive and meet there demand. However this can cause huge amounts of money to be spent by other organisations to ‘clean up’ the pollution that they are causing. On the other hand many farming techniques designs to reduce the amount of pollution being caused from agriculture rely heavily on government funding in the form of incentives, which may reduce the environmental impacts but cost the country money. As conflicts can occur between the management of pollution issues there are many policies and legislations designed to minimise the effects of agricultural pollution and many try and find a balance between economic activity and the environment, such as the pressure-state-response frame work. [14] The best way to manage the pollution incidents I believe is through the ‘prevention’ rather than ‘cure’. I believe that encouragement and search of practical solutions to reduce agriculture pollution is the best way to combat the problem. I also feel that compromises will have to be made both financially and environmentally to achieve the best result.