As we all know, agriculture is the single largest user of freshwater resources, 70% of all surface water supply global average. In addition to the water through evaporation and transpiration losses, agricultural water is recycled back to the surface water and / or groundwater. However, the agricultural water pollution causes and victims. This is a reason, by emissions of pollutants and sediment surface and / or groundwater by the net loss of soil by poor agricultural practices, and irrigated land salinization and waterlogging. This is a spread to the victims of consumers and farm workers through the use of wastewater and pollution of surface water and groundwater contamination of crops and disease. Agriculture exist in a symbiosis of the land and water, as FAO (1990a), it is clear, "must take appropriate steps to ensure that agricultural production activities will not adversely affect water quality and the subsequent use of the water for different purposes is not compromised. "
· Establishment and operation of cost-effective water quality monitoring systems, agricultural water use.
· Prevention of other social and economic activities, water quality and agricultural activities on wetlands, especially through the best use of farm inputs and minimize the use of external inputs in agricultural activities adversely affected.
· Establish the biological, physical and chemical water quality standards for agricultural water users and the marine and river ecosystems.
· Prevent soil erosion and sedimentation.
· Proper disposal of sewage from the feces of human settlements and intensive livestock production farms.
· Minimize the adverse effects of the agricultural chemicals used in integrated pest management.
· Use of fertilizers and chemicals pollution impact on water quality and food safety community education.
This publication specifically for the field of agriculture freshwater quality. Classification of the impact of non-point source - especially sediment, pesticides, nutrition and pathogens - determined together with the ecology, public health, and appropriate legal consequences. Evaluation of technical and control measures were recommended. Developed countries on agricultural scientific literature, surface water and groundwater quality, reflecting a wide range of scientific problems, in some cases, since the 1970s, the attention of the regulatory authorities. Scientific discovery and management principles, however, generally applicable worldwide. This publication does not deal with the impact of water quality, food processing and other industries, because these are considered to be a point source and control sewage regulatory and law enforcement.
Agriculture, fresh water, as the largest single user on a global scale, and an important cause of degradation through erosion and chemical runoff, surface water and groundwater resources, global impact water quality concern. Agricultural food processing industry is organic sources of pollution, in most countries, there are significant. Aquaculture is one of the main problems of the currently accepted freshwater, estuarine and coastal environments, leading to eutrophication and ecosystem destruction. Environmental and public health problems of global freshwater quality problems
Actual and potential development opportunities in many countries because of the transfer of funds for water pollution restoration noted loss. In 1994, the quantity and quality of water management in Asia and the Pacific, (ESCAP) Economic and Social Committee held a meeting of experts on the Asian representatives approved a declaration calls for national and international action to assess the loss of economic opportunity, due to water pollution, "looming water crisis", in order to determine the potential economic impact. Interestingly, the the ESCAP conference delegates concern is to prove that, rather than simply economic sustainable development of water pollution impact on the environment. Credibility attention (Matthews, 1993), because the lending institutions now take a look at the economic benefits of the remedial costs. There is also concern that, if the remedial costs exceed the economic benefits, the development of the project may no longer be in good standing. Sustainable development of agriculture, the inevitable need to factor into the bigger problem of sustainable water resources planning and economic development in various economic sectors. In the policies of the World Bank (1993), water resources development, water resources management has always stressed that such a comprehensive way. The old chlorinated agricultural pesticides have been implicated in a variety of human health problems, and by the toxic effects on organisms caused significant and widespread ecological system dysfunction. Generally prohibited in developed countries, there is now a concerted international efforts to ban the global persistent organic pollutants (POPs), part of the agreement. An example of such efforts is the Intergovernmental Conference on the Protection of the Marine Environment from Land-based Activities, UNEP jointly held in Washington in 1995.
Non-point source pollutants, regardless of their origin, land transport, and through the soil of the rain and melting snow. These pollutants eventually find their way into the groundwater, wetlands, rivers and lakes, ocean rivers carry sediment and chemical load. As described below, these pollutants range from simple nuisance substances including fish, birds and mammals, and serious ecological impacts of ecological environment on human health. Range of agricultural non-point source pollution and relatively complex, shown in Figure 1.
What is undoubtedly the earliest and is still the most widely used non-point source pollution, Canada and the United States carried out a major plan, identification and control of the entire Great Lakes basin point source and non-point source in the 1970s. Precipitate the attention of the public (such as news reports said, "Lake Erie is dead!") The deterioration of water quality, including aquatic plants algae blooms, the clear evidence of increased. Science, this situation is hypertrophic conditions, eutrophication of Lake Erie and Lake Ontario conditions caused by an excess of phosphorus from point sources and non-point source into the Great Lakes. The two countries, according to the bilateral Joint Commission International, established a "reference group" from land use activities (called "PLUARG") as the 10-year study of the scientific vehicle, from the sources of pollution of the Great Lakes basin, and eventually lead to significant changes in the point source and non-point source control. The study also led to the impact of land use activities on water quality in the scientific understanding of unprecedented growth. This work, mainly in the 1970s and early 1980s, the concerns of non-point source, in other parts of the world still has great relevance.
These terms enriched levels of nutrients in the water, those described in Chapter 3.
PLUARG study, through the analysis in the Great Lakes region of the river monitoring data from the detailed study of the experimental and representatives tributaries catchment and agricultural practice from the field and plot found in the general case, the non-point sources and agriculture, especially is a major source of pollution in the Great Lakes. Evaluate the relative contribution of point source and non-point source pollution load of the Great Lakes, point source control and modify the land using PLUARG study proposed merger plan. The results of the federal government and coastal national and provincial government to implement these recommendations, the two lower most serious impact of the Great Lakes (Lake Erie and Lake Ontario) water quality and ecosystems in the past decade has occurred significant improvements. The agricultural sector is an important factor in the high level of public participation and education. Agricultural practices, in many cases, by demonstrating to the farmers, through changes in land management practices to achieve economic gains.
In most industrialized countries, the focus has always been on the point source water pollution control management. In the United States, it may be reasonably typical of other industrialized countries, the economy is facing a challenge to further increase the regulation of point sources, in particular, is known, which agricultural non-point source of comprehensive and extensive?? That more and more people, despite billions of dollars for the point source control measures, further point source control can not achieve significant additional water quality benefits no significant control non-point source. In this case, it is relevant to note that agriculture is considered to be the main problem of non-point source. Table 2 lists the United States Environmental Protection Agency (1994) on the results of a study ranking sources, deterioration of water quality, rivers, lakes and estuaries.
One of the few countries of the U.S. national statistical system to produce a point source and non-point sources of water quality impairment. U.S. Environmental Protection Agency (US EPA) report to Congress in 1986, the report said, 65% of the assessment of the rivers located in the United States of non-point source. Similarly, in a recent study, the United States Environmental Protection Agency (1994) identified the primary cause of agriculture, the impairment of the water quality of rivers and lakes in the United States (Table 3) and the importance of the third estuarine pollution. Agriculture also influential in the types of pollutants, as pointed out in Table 3. Sediment, nutrients and pesticides to occupy the first four categories, and significantly related to agriculture. Although these findings suggest that the importance of agriculture in water pollution, the ranking will change the country in less control of the point source. However, the rankings change point source control is effective, but not any less polluting agricultural nonpoint source pollution.
The contaminated water is an important cause of human disease, suffering and death. According to the World Health Organization (WHO), as many as 400 million children die each year due to diarrhea caused by water-borne infections. The most common bacteria in the sewage coliform bacteria excreted by humans. Surface runoff, the contribution of non-point source pollution significantly high level of surface water pathogens. Rural health facilities are poorly designed, but also conducive to the contamination of groundwater.
Direct and indirect causes of agricultural pollution on human health. The WHO report said, the nitrogen content in the groundwater, growth in many parts of the world, due to intensive farming practices "(WHO, 1993). This phenomenon is well known in the European parts. Growth in some countries, of which more than 10% of the population exposure guidelines nitrate content in drinking water is higher than 10 mg / L nitrate content. While the World Health Organization found no link between the significant nitrate and nitrite in human cancer, drinking water guidelines to prevent methemoglobinemia, infants are particularly vulnerable (WHO, 1993). Although this problem is well documented, nitrogen pollution of groundwater in developing countries is a problem.
(1986) reported that of nitrate in Lawrence and Kumppnarachi, near the intensively cultivated irrigated rice irrigation wells close to 40-45 mg / l concentration. Figure 3 shows the changes N0 3-N, which indicates that the poetry (main) planting season of rice cultivation in Sri Lanka the most intensive peak period. |
