4.1 Investigation and Monitoring on Key Industrial Wastewater Pollution Sources

In 2003, the 54 key industrial pollution sources that discharge wastewater to the Yangtze River directly discharged a total of 184 million tons of industrial wastewater into the Yangtze River, with an increase of 27.8% compared with 2002. The largest amount of industrial wastewater discharge was from the main urban area of Chongqing Municipality (including districts of Ba'nan, Dadukou, Jiulongpo, Nan'an, Yuzhong, Jiangbei, and Yubei), with a discharge of 60.119 million tons, accounting for 32.8% of the total.

The 54 key industrial pollution sources discharged a total of 25,000 tons of various pollutants, with an increase of 152.5% compared with 2002. Among these pollutants, COD was 24,087.5 tons, ammonia nitrogen was 848.9 tons, oil was 84.4 tons, hexad chromium was 949.6 kg and volatile phenol was 467.0 kg, increasing by 155.3%, 92.7%, 22.9%, 45.2% and 6.9% compared with 2002 respectively.  Lead was 9.6 kg, decreasing by 90.5% compared with 2002. Major pollutants were COD and ammonia nitrogen with pollution loading up to 78.0% and 18.3% respectively, accumulative pollution loading up to 96.3%. Major areas of pollutant emission centered on districts of Fuling, Changshou, Dadukou and Jiulongpo with pollution loading up to 47.8%, 24.4%, 12.7% and 4.8% respectively, accumulative up to 89.7%.

Table 4-1 Discharge of Pollutants from 54 Key Industrial Wastewater Sources that Discharged Wastewater Directly into the Yangtze River in the Three Gorges Reservoir Area in 2003

Region	Wastewater (10,000t)	COD	Oil	Ammonia	Cr+6	Pb	As	Volatile	Cyanide
		(t)	(t)	nitrogen(t)	(kg)	(kg)	(kg)	phenol (kg)	(kg)
Jiangjin	3365.6	726.8	0.1	0.9	0	0	0	250	28
Dadukou	35.9	76.1	1.4	0	0	0	0	0	0
Jiulongpo	2636.1	1899.7	59.6	202.9	377.1	0	0	0	0
Yuzhong	90.6	72.1	0	0	0	0	0	0	0
Nan’an	980.3	764	4	0	0	0	0	0	0
Jiangbei	1211.6	466.9	0	1.5	27.2	9.6	0	0	0
Yubei	1057.4	1160.1	0.3	45.8	0	0	0	0	45
Changshou	3468.8	6653.9	19	80.8	542	0	0	217	0
Fuling	3036.3	11350.1	0	510.9	3.3	0	0	0	2.8
Fengdu	7.2	9.2	0	0	0	0	0	0	0
Zhongxian	464.2	344.9	0	6	0	0	0	0	0
Wanzhou	1000.5	210.2	0	0.1	0	0	0	0	0
Yunyang	770.3	289.1	0	0	0	0	0	0	0
Fengjie	232	64.5	0	0	0	0	6.5	0	0
Total	18356.7	24087.5	84.4	848.9	949.6	9.6	6.5	467	75.8

The major industrial sectors of the 54 key industrial pollution sources were chemical materials and products manufacturing sector, foodstuff, tobacco and beverage processing sector, chemical fibre manufacturing sector and producing and supplying sector of electricity, coal, gas and water with pollution loading up to 42.6%, 31.6%, 8.8% and 7.5% respectively, accumulative up to 90.4%. The wastewater discharged accounted for 81.0% of the total discharge of industrial wastewater.

4.2 Investigation and Monitoring on Urban Wastewater

In 2003, there were 66 outlets that discharged urban wastewater directly into the Yangtze River, with total discharge of 404 million tons, 26.6% more than that in 2002. The wastewater discharge volume from the main urban area of Chongqing Municipality, Wanzhou District and Fuling District was comparatively large, 253 million tons, 43 million tons and 28 million tons, accounting for 62.6%, 10.6% and 6.9% of the total respectively.

The total pollutants in the urban wastewater amounted 261,300 tons, 27.0% more than that of 2002. Among them, COD, BOD₅ and ammonia nitrogen were 157,700 tons, 76,800 tons and 9,700 tons, accounting for 60.4%, 29.4% and 3.7% of the total volume of pollutants respectively. The major pollutants were total phosphorus, BOD₅ and COD, with pollution loading 47.3%, 24.9% and 15.4% respectively. The accumulative loading reached 87.6%. The pollutants in the wastewater came mainly from the main urban area of Chongqing Municipality, Wanzhou District, Fuling District, Changshou District and Ba'nan District, with pollution loading 62.5%, 10.7%, 7.0%, 4.2% and 2.6% respectively. The accumulative loading reached 87.0%.

Table 4-2 Statistics of Wastewater Directly Discharged into Yangtze River in the Three Gorges Reservoir Area in 2003

City	Number of outlets	Discharge	COD	BOD5	Ammonia nitrogen	Total nitrogen (t)	Total phosphorus	Volatile phenol	Total
		(10000t)	(t)	(t)	(t)		(t)	(t)	(t)
Jiangjin	1	368.89	1438.7	700.89	88.53	132.8	22.13	0.22	2383.25
Ba’nan	2	1062.13	4142.3	2018.04	254.91	382.37	63.73	0.64	6861.98
Main urban area	19*	25266.27	98538	48005.91	6063.9	9095.86	1516	15.16	163235
of Chongqing
Changshou	3	1714.58	6686.8	3257.69	411.5	617.25	102.9	1.03	11077.2
Fuling	8	2829.81	11036	5376.63	679.15	1018.73	169.8	1.7	18282.3
Fengdu	4	682.8	2662.9	1297.31	163.87	245.81	40.97	0.41	4411.27
Zhongxian	2	932.48	3636.7	1771.7	223.79	335.69	55.95	0.56	6024.35
Wanzhou	9	4339.54	16924	8245.13	1041.49	1562.24	260.4	2.6	28036.1
Shizhu	1	83.66	326.28	158.96	20.08	30.12	5.02	0.05	540.51
Yunyang	3	557.74	2175.2	1059.71	133.86	200.79	33.46	0.33	3603.35
Fengjie	4	1045.77	4078.5	1986.96	250.98	376.48	62.75	0.63	6756.3
Wushan	3	836.62	3262.8	1589.57	200.79	301.18	50.2	0.5	5405.04
Badong	5	571.69	2229.6	1086.21	137.2	205.81	34.3	0.34	3693.44
Zigui	2	153.38	598.18	291.42	36.81	55.22	9.2	0.09	990.92
Total	66	40445.34	157737	76846.14	9706.88	14560.3	2427	24.27	261301

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

4.3 Investigation on Urban Garbage

In 2003, a total of 1.3506 million tons of urban garbage was generated in the Three Gorges Reservoir area, 562,400 tons less than 2002. The main urban area of Chongqing Municipality generated the largest amount, i.e., 842,200 tons, accounting for 62.4% of the total urban garbage. Wanzhou District, Fuling District and Changshou District also generated large amount of garbage, i.e., 144,700 tons, 94,300 tons and 57,200 tons, accounting for 10.7%, 7.0% and 2.6% of the total respectively.

4.4 Investigation on Pollution in Towns to Be Moved Out

In 2003, investigation was conducted again on pollutant discharges from the 89 key towns and townships to be moved out with pollution loading accounted for 80% of the total. The number of key towns and townships investigated was 3 less than that of 2002 because some towns had been combined.

The total number of permanent residents in these towns was 1.328 million (for some towns, only the residents to be moved out were considered). The annual wastewater discharge reached 74 million tons, with 25,400 tons of COD, 11,900 tons of BOD₅, 2,200 tons of ammonia nitrogen and 450 tons of total phosphorous.

By June 2003, the cleaning up of the Three Gorges reservoir had been completed. The garbage accumulated for many years under the water level line of 135m had been cleaned up. In 2003, the domestic garbage generation of the towns to be moved out amounted to 508,000 tons, among which, Fuling District and Wanzhou District generated more than others, accounting for 22.6% and 18.7% of the total respectively. All these new generated garbage was treated through burying or burning.

In 2003, a total of 202 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 9.2862 million tons, of which 7.6457 million tons were treated, with a treatment rate of 82.3%. Major pollutants were COD and BOD₅, i.e., 1,269.62 tons and 1,181.73 tons respectively. The solid waste generated from these enterprises was 445,400 tons per year, of which 307,400 tons were reused, while 80,200 tons were disposed. The accumulated waste reached 48.6119 million tons.

The results of reinvestigation made in 2003 on pollutant discharges from towns to be moved out in the Three Gorges reservoir area were basically the same as that of 2002. But compared with 2002, discharge volume of each industrial sector dropped a little, especially the chemical industry and textile industry. Volume of wastewater treatment increased in all sectors and discharge volume decreased or increased in different sectors but within a narrow range. The main cause for the decrease of wastewater discharge in paper milling and manufacturing sector was that the municipal government of Chongqing devoted more efforts to rectifying the small paper mills with low yield but high pollution.

4.5 Monitoring of Pesticides and Chemical Fertilizers

In 2003, investigation was made on the use of pesticides and chemical fertilizer in the 181 towns and villages of the 19 counties in the reservoir area. The results 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 to give more favor to nitrogen and phosphorus fertilizers than to kalium fertilizer, resulting in over loss of nitrogen and phosphorus polluting the water body of the Yangtze River. The total consumption of pesticides was reduced. The organic phosphorus pesticides were used in the largest amount.

4.5.1 Chemical fertilizers

In 2003, the total use of chemical fertilizers in the reservoir area, calculated as pure amount, was 110,200 tons, 14.2% decrease compared with 2002, in which 77,900 tons of nitrogen fertilizer, 22,000 tons of phosphorus fertilizer and 10,300 tons of kalium fertilizer 12.0%, 21.2% and 15.6% decrease compared with 2002 respectively. The per hectare use of fertilizers was 527.5 kg, 4.7% decrease compared with 2002.

The ratio of nitrogen, phosphorus and kalium was 1:0.28:0.13, still unreasonable with over use of nitrogen and phosphorus fertilizers.

Table 4-3 Use and Loss of Chemical Fertilizers in the Reservoir Area in 2003

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	7.79	0.8	35.16	30.31	9.53	0.54	24.46	－
Phosphorus	2.2	0.13	34.16	13.18	5.27	0.72		46.67
Kalium	1.03	－	－	－	－	－	－	－
Total	11.02	－	－	－	－	－