Agricultural Non-point Source Water Pollution Caused Eutrophication of Dianchi Lake in China and Possible Solutions Abstract: Eutrophication is a big problem around the world and especially in China where laws and regulations are not followed in rural areas. This is the case in Kunming, Yunnan, China at Lake Dianchi where eutrophication is the highest in the country. This case study will set up to study the effects of phosphate in the lake, the quantity of phosphate, and the possible source of the phosphate.
From there the effects of plant and animal life will be discussed as well as the availability of water to be used for agriculture and potability of the water. Solutions will then be considered that can change the lake from eutrophic conditions to that of tropic ones. Introduction: The intent of this case study is to determine the severity of eutrophication (being the over enrichment of nutrients in a body of water, can be phosphorus or nitrogen, phosphorus will be the focus of the Lake Dianchi study) in the Dianchi Lake and to postulate possible, viable and efficient solutions.
The Dianchi Lake has received a lot of wastewater from 1988-2000; this was a time of growing pollution to the lake and as time goes by it is only getting worse. Lake Dianchi is shown in figure 4. 1 below as an aerial view in the blue. The main source of the pollutant is from agricultural runoff of the surrounding area of the lake. One thing to note is that phosphorus is one of the leading causes of eutrophication in the body of water, just above nitrogen. This pollution is due to national regulation not being met because of the isolation of the area from any big city or government.
The reason the lake is becoming eutrophic is because inorganic fertilizers containing high amounts of phosphate are being used, causing the soil to have too much nutrients. The solutions provided will be ones that include national regulations and incentives and also natural solutions such as adding plants around the lake to absorb the pollutants. Hypothesis: If the farmers in the area of the Dianchi lake cut back on their crop production, thus cutting back on fertilizer and pesticides, and the overnment subsidizes their loss from the social gain that will be acquired from the de-eutrophication of the lake, then the lake will return closer to its natural state and be an efficient solution.  If farmers are equipped with more “environmentally friendly” fertilizers and pesticides, then the lake will not be as eutrophic as it is today. If both of these proposals are met, then the state of the lake will be much less eutrophic. Methodology: This case study will set out to study various other case studies and journal articles on the topic of eutrophication of the Dianchi lake and policy research on the issue.
Graphs and models will be analyzed and shown to give real data and show the reality of the situation at Lake Dianchi. After the data is collected from these sources it will then be analyzed and possible solutions will be put forth. Results and Analysis: There is a major consensus among the scientific community that the leading cause of eutrofication of Lake Dianchi is primarily due to the increase in phosphorus levels. The phosphorus levels have been on an increase, as studied, since 1988, as shown in Fig 2. The leading cause of this pollution, and of high phosphorus levels, is mainly due to agricultural use.
This is because when the farmers use the fertilizer it increases their crop yield, thus increasing their income. A graph of this exact scenario can be seen in figure 4 which show that as one dollar is spent on fertilizer the dollar return is around 6 dollars. It is hard to pin point who is emitting how much pollutants because this is a problem of Non-point source pollution, which is discharged from the ground and diffused throughout the land and eventually ends up in the lake in a very scattered manner. Due to the nature of non-point source pollution it is difficult to charge one source with the pollution.
If the point sources were known, it would be much easier to implement a solution to the phosphorus pollution. This pollution has had a negative effect on the plant and aquatic life of the lake. The amount of phytoplankton has increased, “although the number of species has decreased. The number of individuals per liter of water increased from a few thousand in the 1950s, to around a hundred million in the 1980s, up to several billion in the 1990s. ” This is in direct relation to the amount of phosphorus in the water which promotes algae and plankton life to exist.
The same trend that was shown with phytoplankton can be seen by zooplankton in that the number of species decreased while the amount of them increased. The amount of zooplankton increased from around 2,000 to around 23,000, from 1950 to 1980, respectively.  The loss of indigenous fish life has been seen over the same time frame but another factor might have played a bigger role than the lake eutrofication, this factor is that the lake was introduced with a number of exotic species that have become dominate over the indigenous ones.
The problem of phosphorus eutrofication has also hindered the use of lake water to be used as potable water. There is a major problem within the area of Lake Dianchi because most of the surrounding areas use this water for agriculture and domestic purposes. The phosphorus levels have gotten so high that basic filters can’t purify the water to safe levels.  Figure 4 Possible Solutions: The need for a solution to the phosphorus eutrofication of the water in Lake Dianchi is of utmost concern for the people of that area and for environmentalists worldwide.
Since the source of phosphorus pollution cannot be directly identified other techniques to solve this problem must be postulated and applied. Since the pollution of the lake is costing the local community so much to clean up and maintain, one solution might be to require the farmers and agricultural users of the area to cut back on their production, thus cutting back on phosphorus.  From this the government could pay back the farmers’ lost income from the money saved from the clean up and maintenance.
This solution could also entail the use of more organic fertilizers, which would cut back on phosphorus levels.  A graph below shows how this system would work. Normally the farmer would be at YF0 which uses more agricultural chemicals and at F0 is how much profit the farmer makes on their own, but at YF1 is where the government subsidizes their loss when the farmer declines their production, thus decreasing the amount of phosphorus in the lake.  If, on top of the government subsidies, the farmer switches to organic fertilizer than there will be an ever greater decrease in phosphorus levels. 2] An additional economical solution would be to use incentives so that farmers get rewarded for meeting a certain standard of phosphate use. This alone would not work if the cost for not meeting incentives is less than their net gain from their profit. Incentives could potentially work when intertwined with other viable solutions to reduce the phosphate in Lake Dianchi. Another possible solution to the phosphorus eutrofication in Lake Dianchi would include three things: one would be to somehow decrease the slope of the surrounding land, this would restrict the flow of phosphorus by hindering runoff.
A further possibility would be to apply finer grain sediments in the soil around the lake; this would restrict the phosphorus from flowing by blocking it with the fine sediments. Finer grains sediments restrict flow, more so than larger grains, because finer grains can hold more fluid due to their low amount of pore space. The last of the three options, or a third to be included with the other two, would be to increase the amount of plant life around the lake, again hindering infiltration of phosphorus into the lake. 
With cost set aside, another solution, not implementing lower phosphate levels, would be the use of iron (Fe) and aluminum (Al) phosphate filtration paper. This could be used to line the ground around the lake. The iron and aluminum capture the phosphate and would be a possible solution to lower, or eliminate, phosphate levels of Lake Dianchi. The paper would be oriented in a vertical manner from ground surface down to a specified depth, or as far as phosphate infiltrates. This could be a very high cost solution because every paper has to be impregnated with “10g FeC136H2O and 5g AlC136H20 in 100mL of distilled water”. 5] This amount of both Fe and Al are used to create only a “2 by 12. 5 cm” filtration paper strip. The price of this alone is estimated to be high, just imagine how high it would be for a much larger scale project to cover the land around Lake Dianchi. Reforming some agricultural plots of land near Lake Dianchi from inorganic fertilizers to organic fertilizers would eliminate phosphorus in that area. Organic fertilizers are much healthier for the land, they do not leach any phosphorus as inorganic fertilizers do, and they keep the soil viable to support plant life.
The use of organic fertilizers does have one drawback to that of inorganic fertilizers, it takes time for the soil to break down the organic material and use the nutrients. Although this process would need more time, farmers that do not need to produce crops immediately could use this alternative and cut their phosphorus levels down dramatically. In 2003 there was a major effort put forth to clean up the lake after extensive studies. “3. 536 billion Yuan”  was spent over a five year period in order to fix this pollution problem of Lake Dianchi through extensive projects.
These results included: “All the industrial polluters in the Lake Dianchi drainage basin have basically complied with the discharging standard; Water pollutant discharge licenses were issued to 777 industrial enterprises; eight sewage treatment plants, with treatment capacity of 585,000 m3/d, have been put into operation; a mixed sewerage system in the urban area, comprising truck/main sewers and connections, has been established to bring the sewage treatment plants into functioning; The urban sewage treatment ratio in the dry season increased from 60% in 2000 to 80% in 2004; A number of the polluted river[s] passing through Kunming City into the lake were diverted as sewage delivery systems; The interceptor at the north bank of Lake Dianchi can intercept 300,000 m3/d of polluted river water from the urban area; Forest coverage in the drainage basin is up to 50. 6%; More than 4 million m3 of contaminated sediment were dredged, removing 8,230 tons of total nitrogen (TN), 1,885 tons of total phosphorus (TP) and 4,431 tons of heavy metals from the lake; and, There is a ban on phosphate-containing detergents in the basin. ” Conclusion: The problem with eutrofication is not one happening just in China, though it is higher in intensity there, but it is felt throughout the world. The case studies that were looked through showed that increasing inorganic fertilizers increases the amount of phosphorus in a body of water, and also the surrounding land.
From the increase in phosphorus in Lake Dianchi comes greater effects on plant and animal life, mainly that of algae. It also has an effect on the available water for the use of humans from agriculture to domestic uses. From studying this lake it can be seen that this is a sustainability issue as well, because if business goes as usual the water will not be able to be used at all and there will be very little plant and animal life present. The solutions put forth will have a positive effect on the quality of the water and ability for it to be used as normal. If any, or all, of the solutions are put into play than there will be a drastic turn around in the phosphorus levels in the lake.
From the projects implemented, the results sound astounding compared with what would have gone if no one did anything. Though the current conditions of Lake Dianchi are healthier than they were before, the new “pollution controls cannot keep up with pollution generation. ” There seems to be a greater interest in China for economic growth rather than environmental health. References: 1. Edwards, Clive Arthur. Sustainable agricultural systems. 1st. United States of America: 1990. 254. Print. 2. Huang, Yingna, Tianzhu Zhang, Siyu Zeng, and Jining Chen. “Policy Research on Agricultural Non-point Source Water Pollution Control in Dianchi Lake Area of China. ” 2004. Third World Congress of Environmental and Resource Economists, Web. 2 Nov 2009. 3. Liu, Y. 2005.
Phosphorus Flows in China: Physical Profiles and Environmental Regulation. PhD Thesis, Environmental Policy Group, Department of Social Sciences, Wageningen University, Wageningen, the Netherlands. 4. Xiangcan, Jin, Li Wang, and He Liping. “Lake Dianchi Experience and Lessons Learned Brief. ” 2006. Jin Xiangcan, Web. 2 Nov 2009. 5. Sharpley, Andrew N. “Soil Phosphorus Extracted By Iron-Aluminum-Oxide-Impregnated Filter Paper. ” 07 Jan 1991. National Agriculture Water Quality Lab, Web. 17 Nov 2009. 6. Zhang, Nai-Ming et al. “Factors Influencing Runoff P Losses from Farmlands of the Dianchi Lake Watershed in Yunnan, China. ” Pedosphere 14. 2 (2004): 259-262. Web. 17 Nov 2009.