外文翻译尼罗河体系的水质评价综述.docx

1、外文翻译尼罗河体系的水质评价综述中文3790字附录(外文翻译)BIOMEDICAL AND ENVIRONMENTAL 17,87-100(2004)Water Quality Assessment of the River Nile System: An OverviewRIFAAT A. WAHAAB AND MOHAMED I. BADAWYNational Research Center, Dokki, Cairo, Egypt Objectives： The main objective of the present article is to assess and evaluate

2、 the characteristis of the Nile water system，and identify the major sources of pollution and its environmental and health consequences. The article is also aimed to highlight the importance of water management via re-use and recycle of treated effluents for industrial purpose and for cultivation of

3、desert land. Method An intensive effort was made by the authors to collect, assess and compile the available data about the River Nile. Physico-chemical analyses were conducted to check the validity of the collected data. For the determination of micro-pollutants, Gas Chromatography (GC) and High Pe

4、rformance Liquid Chromatography (HPLC) were used. Heavy metals were also determined to investigate the level of industrial pollution in the river system. Results The available data revealed that the river receives a large quantity of industrial, agriculture and domestic wastewater. It is worth menti

5、oning that the river is still able to recover in virtually all the locations, with very little exception. This is due to the high dilution ratio. The collected data confirmed the presence of high concentrations of chromium and manganese in all sediment samples. The residues of organo-chlorine insect

6、icides were detected in virtually all locations. However, the levels of such residues are usually below the limit set by the WHO for use as drinking water. The most polluted lakes are Lake Maryut and Lake Manzala. Groundwater pollution is closely related to adjacent (polluted) surface waters. High c

7、oncentrations of nutrients, Ecoli, sulfur, heavy metals, etc. have been observed in the shallow groundwater, largely surpassing WHO standards for drinking water use. Conclusion A regular and continuous monitoring scheme shall be developed for the River Nile system. The environmental law shall be enf

8、orced to prohibit the discharge of wastewater (agricultural, domestic or industrial) to River Nile system.Key words: Water quality; River Nile; Lakes; Pollution sources; AssessmentINTRODUCTION The availability of water of acceptable quality in Egypt is limited and getting even more restricted, while

9、 at the same time, the needs for water increase as a result of population growth, industrial development and cultivation of desert land. The country depends for more than 90 percent of its water supply on the River Nile. Groundwater resources are limited and the direct contribution of rainfall, exce

10、pt for the Mediterranean coastal area, is neglected. Irrigated agriculture is by far the largest consumer of water (almost 90percent) and,although advances in irrigation and agricultural technologies stimulate water conservation,further intensification of crop schedules and extension of agricultural

11、 areas put an increasing demand on the already scarce water resources. Competing demands between industrial development and human consumption are puttinga severe strain on a balanced allocation ofthe limited resources to the various users.Water Resources The River Nile forms the main water resource

12、of Egypt. Through the 1959 Nile Water Agreement with Sudan and the completion of the High Aswan Dam in 1968, a stable 55.5 billion m3/yr. was allocated to Egypt. The actual release from the High Aswan Dam shows very little yearly variation. Annual variation of the release of water from the High Aswa

13、n Dam depends mainly on irrigation needs. The release from the high Aswan Dam ranges from approximately 800 m3/s during the (winter) closure period to approximately 2 760 m3/s during the summer months. In the Nile Valley and Nile Delta, groundwater resource use mainly being recharged from the Nile a

14、nd from account for approximately 4.4 billion m3/yr.,seepage from irrigated agriculture. Rainfallsplays a minor role in Egypts water resources, with average rainfall rates declining from 200 million m3/yr. at the Mediterranean Coast to 20 mm .in Cairo and almost zero in Upper Egypt.Water Consumption

15、In the 1993/94 hydrological season, gross water consumption of irrigated agriculture amounted to approximately 54.5 B. (billion) m3/yr. (of which almost 30 B. m3/yr. occurred in the Delta). Other water users, such as municipal and domestic drinking water s industry and others consumed approximately

16、8.8 B，and an estimated 2.0 B. about 14.0 B. was lost through evaporation anddischarged to the Mediterranean Sea (Table 1). In recent years, theamount discharged to the Mediterranean Sea directly from the River Nile system, declin3ed sharply, in favour of agricultural and drinking water use approxima

17、tely 2.3.m discharged in 1990 compared with approximately 1.2B.Cu y t3h.e release. of water from the High Aswan Dam (HAD), varies between 52.9 and 57.4 B. m-iyr. with rncreasmg expected uses, Egypt will nave to rely on groundwater aquifers and on expensive desalinization of sea water. Therefore the

18、existing renewable resources must be extremely carefully managed to adequately supply the rapidly increasingpopulation and industrial activity, through options such as increased efficiency of irrigation and/or changes in crop types, and reducing areas under irrigation. The current water use from the

19、 Nile River and projections to year 2000 shows a rapid increase in demand, which isprojected to be met by using water from the drains and reducing the flow from drainsto the sea. This poses serious issues since the water in the drains is currently of poor quality due to pollution from industrial, mu

20、nicipal and agricultural sources.Industrial PollutionDeterioration of its surface and groundwater due to Egypt faces a rapidly increasing and industrial effluents into its discharges of heavily polluted domesticin agriculture also causes water waterways. Excessiveuse of pesticides and fertilizers po

21、llution problems. Egyptian industryuses 638 M. m3/yr. of water, of which 549 M. m3/yr. is discharged to activities in the Greater Cairo and Alexandria regions use the drainage system. Industrial 40% of the total. The River Nilesupplies 65% of the industrial water needs and receives more than 57% of

22、its effluents.More detailed information about water consumption, sourcesof pollution and loads from different industrial wastewater discharge and point sectors are provided. The area has a population of approximately a million and encompasses many industrial and commercial activities. Heavy industry

23、 is located around South of Cairo, and, North of Cairo. Many small industries and some heavy industry are randomly located throughout the city. Although wastewater discharges of the small industries are generally low, concentrations of certain industries in specific areas, such as the tanning overvi

24、ew cause local contamination problems. Anof pollution sources is include 23 chemical industries, 27 textile and spinning industries, 7 steel and galvanizing industries, 32 food processing industries (including a brewery), 29 engineering industries, 9 mining and refraction industries, and petrol and

25、car service stations. Bakeries (350), marble and tile factories (120) and tanneries are located in South Cairo. Alexandria is a major industrial center with some 175 industries, about 25 percent of the total in Egypt. These industries include paper, metal, chemical, textile, plastic, pharmaceutical,

26、 oil and soap, and food processing. These plants are reported to contribute some 20 percent of the total wastewater of Alexandria. The industries discharge theireffluents mainly to Lake Mariut and pardsewerage network. According to a survey made by Drainage Research Intypes of industriallirectly to

27、the lake wastes are disposed to Lake Maryut. At least 17 factories through pipelines; 4 factories collect their wastewater in I lying in the vicinity of the treatment plants; 22 factories discharging to nearby drains and then to the lake. It is worth mentioning that the totalamount of BOD discharged

28、 to the River Nile by industrial plants equals 270 ton/day. Thisamount corresponds to the untreated discharge of wastewater from more than six million people. It can be concluded that these substances are discharged mainly from the industrial activities in the Greater Cairo region and in Delta (0.75

29、 and 0.50 ton/day). The average concentration of heavy metals (HM) in the effluentis less than 5 pg/L, which is slightlymore than a normal background figure (Table 2 C).Domestic Pollution The way domestic pollution affects water quality heavily depends on the way ofdisposal of this pollution. Approx

30、imately 65 percent of Egypts population is connected to drinking water supply and only 24 percent to sewerage services, although the latter percentage is expected to grow rapidly, due to works under construction. The population not connected to sewerage systems relies on individual means of excreta

31、and wastewater disposal such as latrines and septic tanks. According to ananalysis of the different references (World Bank, 1993), in Upper 8 wastewater treatment facilities exist with a total capacity of roughly 120 000 with approximately the same amountunder construction now. In Greater Cairo, 5 w

32、astewater treatment plants exist, with a totalcapacity of approximately 1 850 000m3/day. In the delta there are more than 30 wastewater treatment facilities with a total capacity of almost 400 000 , with some 100 000 m3/dayunder construction. In Upper Egypt and in the Delta, some domestic wastewater

33、 receives treatment. In the Greater only primary Cairo area,the sewerage systems also serve small industries and commerce.Agricultural PollutionAgricultural is the major non-point sourcepollution, with a number of potential impacts on the environmental and human health. In many agricultural areas, local surfaceand groundw