1、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 Overview RIFAAT A. WAHAAB AND MOHAMED I. BADAWY National Research Center, Dokki, Cairo, Egypt Objectives： The main objective of the present article is to assess and evaluate the ch
2、aracteristisof 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 desert
3、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 Performan
4、ce 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 mentioning t
5、hat 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 insecticides
6、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 concentr
7、ations ofnutrients, Ecoli, sulfur, heavy metals, etc. have been observed in the shallow groundwater, largely surpassing WHO standards for drinking water use. Conclusion A regular and continuousmonitoring scheme shall be developed for the River Nile system. The environmental law shall beenforced to p
8、rohibit the discharge of wastewater (agricultural, domestic or industrial) to River Nile system. Key words: Water quality； River Nile； Lakes； Pollution sources； Assessment INTRODUCTION The availability of water of acceptable quality in Egypt is limited and getting even morerestricted, while at the s
9、ame time, the needs for water increase as a result of populationgrowth, industrial development and cultivation of desert land. The country depends for morethan 90 percent of its water supply on the River Nile. Groundwater resources are limited andthe direct contribution of rainfall, except for the M
10、editerranean 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,furtherintensification of crop schedules and extension of agricultural areas put an
11、increasingdemand on the already scarce water resources. Competing demands between industrialdevelopment 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 of Egypt. Throu
12、gh the 1959 Nile WaterAgreement with Sudan and the completion of the High Aswan Dam in 1968, a stable 55.5billion m3/yr. was allocated to Egypt. The actual release from the High Aswan Dam showsvery little yearly variation. Annual variation of the release of water from the High AswanDam depends mainl
13、y on irrigation needs. The release from the high Aswan Dam rangesfrom approximately 800 m3/s during the (winter) closure period to approximately 2 760 m3/sduring the summer months. In the Nile Valley and Nile Delta, groundwater resource usemainly being recharged from the Nile and from account for ap
14、proximately 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 to20 mm .in Cairo and almost zero in Upper Egypt. Water Consumption In the 1993/94 hydrol
15、ogical 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 othersconsumed approximately 8.8 B， and an estimate
16、d 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 approximately 2.3.m discharged
17、 in 1990 compared with approximately 1.2B.Cuy t3h.e release. of water from the High Aswan Dam (HAD), varies between 52.9and 57.4 B.m-iyr. with rncreasmg expected uses, Egypt will nave to rely on groundwateraquifers and on expensive desalinization of sea water. Therefore the existing renewableresourc
18、es must be extremely carefully managed to adequately supply the rapidly increasing population and industrial activity, through options such as increased efficiency of irrigationand/or changes in crop types, and reducing areas under irrigation. The current water use from the Nile River and projection
19、s to year 2000 shows a rapidincrease in demand, which isprojected to be met by using water from the drains andreducing the flow from drainsto the sea. This poses serious issues since the water in thedrains is currently of poor quality due to pollution from industrial, municipal andagricultural sourc
20、es. Industrial Pollution Deterioration of its surface and groundwater due toEgypt faces a rapidly increasingand industrial effluents into itsdischarges of heavily polluted domestic in agriculture also causes waterwaterways. Excessiveuse of pesticides and fertilizerspollution problems. Egyptian indus
21、tryuses 638 M. m3/yr. of water, of which 549 M. m3/yr. is discharged toactivities in the Greater Cairo and Alexandria regions use the drainage system. Industrial40% of the total. The River Nilesupplies 65% of the industrial water needs and receivesmore than 57% of its effluents.More detailed informa
22、tion about water consumption,sourcesof pollution and loads from different industrial wastewater discharge and pointsectors are provided. The area has a population of approximately a million and encompasses many industrial and commercial activities. Heavy industry is located around South of Cairo, an
23、d, 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 overview cause local contamination problems
24、. 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 car service stations. Bakeries (350),
25、 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, oil and soap, and food processing. T
26、hese 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 industrial lirectly to the lake wastes are disposed to Lake
27、 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 to the River Nile byindustrial plan
28、ts equals 270 ton/day. Thisamount corresponds to the untreated discharge ofwastewater from more than six million people. It can be concluded that these substances aredischarged mainly from the industrial activities in the Greater Cairo region and in Delta(0.75 and 0.50 ton/day). The average concentr
29、ation of heavy metals (HM) in the effluentisless 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 of disposal of this pollution. Approximately 65 percent of Egypts population
30、 isconnected todrinking water supply and only 24 percent to sewerage services, although the latterpercentage is expected to grow rapidly, due to works under construction. The population notconnected to sewerage systems relies on individual means of excreta and wastewaterdisposal such as latrines and septic tanks. According
