5.1 Investigation and Monitoring on Key Industrial Wastewater Pollution Sources

In 2002, the 60 key industrial pollution sources that discharge wastewater to the Yangtze River directly discharged a total of 0.144 billion tons of industrial wastewater into the Yangtze River, with an increase of 33.3% compared with 2001. The largest amount of industrial wastewater discharge was from the main urban area of Chongqing Municipality (including districts of Banan, Dadukou, Jiulongpo, Nan'an, Yuzhong, Jiangbei, and Yubei), with a discharge of 49.308 million tons, accounting for 34.3% of the total.

In 2002, the 60 key industrial pollution sources that discharge wastewater to the Yangtze River directly discharged a total of 9900 tons of various pollutants, with an increase of 23.8% compared with 2001. Among these pollutants, COD was 9436.2 tons, ammonia nitrogen was 440.6 tons, and hexad chromium was 654.0 kg, increasing by 24.4%, 35.7%, and 109.6% compared with 2001, respectively. The oil were 68.7 tons, volatile phenol was 436.7 kg, cyanides was 17.3 kg and lead was 91.8 kg, decreasing by 11.4%, 9.2%, 95.8% and 9.0%, respectively, compared with 2001. Major pollutants were COD and ammonia nitrogen with cumulative pollution loading up to 92.4%. Major areas of pollutant emission centered on districts of Changshou, Fuling, Jiulongpo and Jiangjin City, with cumulative pollution loading up to 85.7%.

In 2002, the major industrial sectors of the 60 key industrial pollution sources that discharge pollutant directly to the Yangtze River were production and supply of electricity, coal gases and water, as well as manufacturing of chemical materials and products, chemical fibre, and leather and fur products. Their pollution loading accounted for 87.0%, and the wastewater discharge took 91.8% of the total industrial wasterwater discharge.

5.2 Investigation and Monitoring on Urban Wastewater

In 2002, there were 67 outlets that discharged urban wasterwater directly into the Yangtze River, with total discharge of 319 million tons. The wastewater discharges from main urban area of Chongqing Municipality, Wanzhou District and Fulin District were 191 million tons, 35 million tons and 23 million tons, accounting for 59.9%, 11.0% and 7.2% of the total, respectively.

The total pollutants in the urban wastewater amounted 205800 tons, in which COD and BOD₅ were 124300 tons and 60500 tons, accounting for 60.4% and 29.4%, respectively. The major pollutants were total phosphorus, COD and BOD₅, with pollution loading 47.3%, 24.9% and 15.4%, respectively. Their accumulative loading reached 87.6%. The pollutants in the wastewater came mainly from main urban area of Chongqing Municipality, Wanzhou District, Fuling District and Changshou District, with pollution loading 60.0%, 10.9%, 7.1% and 4.3%, respectively, totaling 82.3%.

Table 5-1 Discharge of Pollutants from 60 Key Industrial Wastewater Sources that Discharged Wastewater Directly into the Yangtze River in the Three Gorges Reservoir Area in 2002

Region	Wastewater discharge	COD	Petroleum	Ammonia nitrogen	Hg	Cd	Cr+6	Pb	As	Volatile	Cyanide
	(10,000 tons)	(t)	(t)	(t)	(Kg)	(Kg)	(Kg)	(Kg)	(Kg)	Phenol	(Kg)
										(Kg)
Jiangjin	3321	645.7	0.2	38.4	－	－	－	－	－	16.7	11.7
Banan	487.7	162.1	0.6	32.7	－	－	－	82	－	－	－
Dadukou	33.8	68.7	1.7	-	－	－	－	－	－	－	－
Jiulongpo	3581	1007.1	43.1	66	－	－	450	3.7	－	－	－
Yuzhong	24.2	36	-	-	－	－	－	－	－	－	－
Nan’an	54.4	55.4	0.4	-	－	－	－	－	－	－	－
Jiangbei	625.4	161.4	3.2	-	－	－	25.2	6.1	－	－	－
Yubei	124.3	137.7	0.5	6	－	－	－	－	－	－	5.6
Changshou	2432.5	4249.6	18.9	13.8	－	－	128.8	-	－	420	-
Fuling	2706.9	1961.6	0.2	283.7	－	－	50	-	－	－	－
Fengdu	15.4	11	－	－	－	－	－	－	－	－	－
Zhong County	46.4	11.6	－	－	－	－	－	－	－	－	－
Wanzhou	295.5	617.4	－	－	－	－	－	－	－	－	－
Yunyang	609.8	277.5	－	－	－	－	－	－	－	－	－
Fengjie	30.5	33.4	－	－	－	－	－	－	－	－	－
Total	14388.8	9436.2	68.8	440.6	－	－	654	91.8	－	436.7	17.3

Table 5-2 Statistics of Wastewater Directly Discharged into Yangtze River in the Three Gorges Reservoir Area in 2002

City	Number	Discharge	COD	BOD5	Ammonia nitrogen	Total	Total	Volatile	Total
	of outlets *	(10000 t)	(t)	(t)	(t)	Nitrogen	Phosphorus	phenol	(t)
						(t)	(t)	(t)
Jiangjin	1	338.78	1321.23	643.68	81.31	121.96	20.33	0.2	2188.71
Banan	2	844.84	3294.86	1605.19	202.76	304.14	50.69	0.51	5458.15
Main urban Area of Chongqing	19*	19112.22	74537.67	36313.22	4586.93	6880.4	1146.73	11.47	123476.42
Changshou	3	1372	5350.78	2606.79	329.28	493.92	82.32	0.82	8863.91
Fuling	8	2259.44	8811.82	4292.94	542.27	813.4	135.57	1.36	14597.34
Fengdu	5	548.22	2138.06	1041.62	131.57	197.36	32.89	0.33	3541.84
Zhong County	2	785.43	3063.19	1492.32	188.5	282.76	47.13	0.47	5074.36
Wangzhou	9	3470.41	13534.6	6593.78	832.9	1249.35	208.22	2.08	22420.93
Shizhu	1	73.58	286.95	139.8	17.66	26.49	4.41	0.04	475.35
Yunyang	2	489.93	1910.72	930.86	117.58	176.37	29.4	0.29	3165.23
Fengjie	4	910.98	3552.82	1730.86	218.64	327.95	54.66	0.55	5885.47
Wushan	4	731.11	2851.32	1389.1	175.47	263.2	43.87	0.44	4723.39
Badong	5	761.11	2968.33	1446.11	182.67	274	45.67	0.46	4917.24
Zigui	2	161.89	631.36	307.59	38.85	58.28	9.71	0.1	1045.89
Total	67	31859.94	124253.71	60533.86	7646.39	11469.58	1911.6	19.12	205834.23

*For the main urban area of Chongqing Municipality, only the outlets that discharge wastewater into the Yangtze River were included, while the outlets that discharge wastewater into Jialing River were excluded.

5.3 Investigation on Urban Garbage

In 2002, a total of 1.913 million tons of urban garbage was generated in the area of Three-Gorges Reservoir. The main urban area of Chongqing Municipality generated the largest amount, i.e., 1.237 million tons. All of the piled garbage was treated when conducting reservoir clean-up. The garbage from the districts and counties along the river was all moved to temporary sites for storage.

5.4 Investigation on Pollution in Towns to Be Moved Out

In 2002, investigation was conducted again on pollutant discharges from the 92 key counties and towns to be moved out. Their total pollution loading accounted for 80% of the total. The number of permanent residents in these towns was 1.241 million (for some towns, only the residents to be moved out were considered). The annual wastewater discharge reached 69 million tons, with 23800 tons of COD, 11200 tons of BOD₅, 2100 tons of ammonia nitrogen and 420 tons of total phosphorus. The annual domestic garbage generation was 0.46 million tons, most of which was piled up along the river banks and valleys while only a small portion was treated by composting and combustion. The accumulative garbage reached about 2.49 million tons, of which large amount was in Wanzhou District, Kai County, Fengdu County and Fuling District.

In 2002, a total of 237 township enterprises were re-examined in 12 industrial sectors including food and beverage processing, tobacco industry, chemical industry and textile industry. The annual wastewater discharge from the township enterprises to be moved out was 9.2316 million tons, of which 7.1829 tons were treated, with a treatment rate of 77.8%. Major pollutants were COD and BOD₅, i.e., 1511.78 tons and 1161.95 tons, respectively. The solid waste generated from these enterprises was 0.376 million tons annually, of which 0.163 million tons were reused while 0.0726 million tons were disposed. The accumulated wastes reached 47.818 million tons.

As the clean-up of the reservoir and the work of "total amount control and reaching the quality standard and emission standard" were further consolidated and the heavier polluting enterprises were gradually closed down, suspended, merged or transformed, the pollution in the towns to be moved out from the reservoir area was alleviated to some extent. As compared with 2000, the pollutant loading from various industries, especially the construction material manufacturing, chemical industry and textile industry, was reduced respectively,

5.5 Monitoring of Pesticides and Chemical Fertilizers in the Reservoir Area

In 2002, the use of pesticides and chemical fertilizers in the 19 counties and 194 towns in the reservoir area was investigated and monitored. The result showed that the use of chemical fertilizers had a trend of declining but the ratios of their use were still not reasonable. It was still common that the use of nitrogen and phosphorus fertilizers was emphasized while the kalium fertilizers were ignored. This resulted in a decrease of absorption in the crops and over loss of nitrogen and phosphorus, which in turn resulted in pollution in the Yangtze River. The total consumption of pesticides was reduced and the composition changed. The organic phosphorus pesticides were used in the largest amount, but the ratio in total pesticide consumption was reduced. The parts of low poisonous pesticides such as organic nitrogen were increased.

5.5.1 Chemical fertilizers

In 2002, the total use of chemical fertilizers, calculated as pure amount, was 0.1287 million tons, 7.2% decrease compared with 2001, in which 88500 tons were nitrogen fertilizers, 27900 tons were phosphorus fertilizers and 12200 tons were kalium fertilizers. The ratio of nitrogen, phosphorus and kalium was 1:0.31:0.14. The per-hectare use of fertilizers was 554.31 kg, 2.2% decrease compared with 2001.

Table 5-3 Use, Utilization and Loss of Chemical Fertilizers in the Reservoir Area in 2002

Type of fertilizer	Total use	Total loss	Utilization rate by crops %	Residue rate in soil %	Surface runoff rate %	Ground leaching rate %	Volatilization of Gaseous nitrogen %	Phosphorus fixed in soil %
	(10,000 t)	(10,000 t)
Nitrogen	8.85