Agricultural Pollution

Over the past few decades, the increase in population and advances made in farming technology has increased the demand for crops and livestock from the agricultural industry. This growth in agricultural production has resulted in an increase in contaminants polluting soil and waterways.

1. Agriculture water pollution

2. I ntroduction Over the past few decades, the increase in population and advances made in farming technology has increased the demand for crops and livestock from the agricultural industry. This growth in agricultural production has resulted in an increase in contaminants polluting soil and waterways.

3. Agriculture water pollution “Any undesirable change in physical, chemical, biological quality of water due to agriculture sources” it is detrimental to human and agriculture too. Acc. To FAO 58% of all water pollution is alone from agriculture

4. Agriculture as a Cause It is a cause through its discharge of pollutants and sediment to surface and/or groundwater, through net loss of soil by poor agricultural practices, and through salinization and waterlogging of irrigated land

5. Sources of AWP Point source from a single discharge point Non-point source to more diffuse, landscape-level causes

6. Point sources Point source pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch.  A way to remember what point source pollution is that you can point to where the pollution came from

7. Non-point source of pollution arises from a broad group of human activities for which the pollutants have no obvious point of entry into receiving watercourses. Called as diffuse source of AWP. non-point source pollution is much more difficult to identify, measure and control than point sources

8. NONPOINT SOURCES Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES

9. Pesticides Pesticides  and  herbicides  are applied to agricultural land to control pests that disrupt crop production. Pesticide leaching Pesticide leaching occurs when pesticides mix with water and move through the soil, ultimately contaminating groundwater. The amount of leaching is correlated with particular soil and pesticide characteristics and the degree of rainfall and irrigation. Leaching is most likely to happen if using a water-soluble pesticide, when the soil tends to be sandy in texture, if excessive watering occurs just after pesticide application, if the adsorption ability of the pesticide to the soil is low

10. Fertilizers Leaching, runoff, and eutrophication The  nitrogen  (N) and  phosphorus  (P) applied to agricultural land (via synthetic fertilizers, composts, manures, biosolids , etc.) can provide valuable plant nutrients. However, if not managed correctly, excess N and P can have negative environmental consequences. Excess N supplied by both synthetic fertilizers (as highly soluble nitrate) and organic sources such as manures  (whose organic N is mineralized to nitrate by soil microorganisms) can lead to groundwater contamination of nitrate. Nitrate-contaminated drinking water can cause  blue baby syndrome . Together with excess P from these same fertilizer sources,  eutrophication  can occur downstream due to excess nutrient supply, leading to  anoxic  areas called dead zones.

11. Heavy metals The major inputs of  heavy metals  (e.g. lead, cadmium, arsenic, mercury) into agricultural systems are fertilizers, organic wastes such as manures, and industrial byproduct wastes. Some farming techniques, such as irrigation, can lead to accumulation of  selenium  (Se) that occurs naturally in the soil. [5]  This can result in downstream water reservoirs containing concentrations of selenium that are toxic to wildlife, livestock, and humans

12. AGRICULTURAL IMPACTS ON WATER QUALITY Surface water Ground water

13. Agricultural impacts on water quality 1. Tillage/ploughing Sediment / turbidity : sediments carry phosphorus and pesticides adsorbed to sediment particles; siltation of river beds and loss of habitat, spawning ground, etc .

14. Impacts Surface water Groundwater 2. Fertilizing Runoff of nutrients, especially phosphorus,leading to eutrophication causing taste and odour in public water supply, excess algae growth leading to deoxygenating of water and fish kills. Leaching of nitrate to groundwater; excessive levels are a threat to public health.

15. 3. Manure spreading Impacts Surface water Groundwater Carried out as a fertilizer activity; spreading on frozen ground results in high levels of contamination of receiving waters by pathogens, metals, phosphorus and nitrogen leading to eutrophication and potential contamination. Contamination of ground-water, especially by nitrogen

16. 4 . Irrigation Impacts Surface water Groundwater Runoff of salts leading to salinization of surface waters; runoff of fertilizers and pesticides to surface waters with ecological damage, bioaccumulation in edible fish species, etc. High levels of trace elements such as selenium can occur with serious ecological damage and potential human health impacts. Enrichment of groundwater with salts, nutrients (especially nitrate ).

17. 22 Irrigation

18. Public health impacts Contamination of water supplies primarily by pesticides and fertilizers. Disease outbreak. Microbiological contamination of food crops. Contamination of food crops with toxic chemicals.

19. Ecological impact Major decline and extinctions of animal, fish and vegetation species. Destruction of major ecosystems.

20. S olutions Nutrient management:  Applying fertilizers in the proper amount, at the right time of year and with the right method can significantly reduce the potential for pollution. Cover crops:  Planting certain grasses, grains or clovers can help keep nutrients out of the water by recycling excess nitrogen and reducing soil erosion.

21. Buffers:  Planting trees, shrubs and grass around fields, especially those that border water bodies, can help by absorbing or filtering out nutrients before they reach a water body. Conservation tillage:  Reducing how often fields are tilled reduces erosion and soil compaction, builds soil organic matter, and reduces runoff. Drainage water management:  Reducing nutrient loadings that drain from agricultural fields helps prevent degradation of the water in local streams and lakes.

22. refrences http://www.conserve-energy-future.com/ www.epa.gov www.wikipedia.org