Comprehensive environmental quality monitoring was conducted in 15 districts (counties) of the migration resettlement area in Chongqing Municipality of the Three Gorges Reservoir area. The major components of the monitoring work were water quality, environmental air quality and acoustic environment quality.

8.1 Water Quality Monitoring

Water quality monitoring work includes the monitoring of surface water quality, water quality of both backwater in sensitive areas and drinking water sources. Water quality evaluation standard and testing methods employed were in accordance with the Standard for the Quality of Surface Water Environment (GB3838-2002). The nutrition evaluation of water bodies would comply with the Technical Regulations on Eutrophication Evaluation Method and Grading for Lakes (Reservoirs) issued by the China National Environmental Monitoring Center.

8.1.1 Surface water quality

A total of 140 river sections were set up in 48 rivers of 15 districts (counties) of the Three Gorges Reservoir area to carry out the monitoring activities, one river and 10 sections more than in the previous year. The water quality evaluation covered 20 items such as pH value, dissolved oxygen, permanganate index, COD, BOD₅, ammonia nitrogen, copper, zinc, fluoride, selenium, arsenic, cadmium, mercury, hexavalent chromium, lead, cyanide, volatile phenol, petroleum, anion surfactant and sulfide.

The monitoring results showed that the overall surface water quality in the migration resettlement areas was fairly good in 2005. 118 sections met or were superior to Grade III national water quality standard, taking up 84.3% of the total, up by 2.0 percentage points than in 2004.Six sections met Grade IV standard, 5 met Grade V standard and 11 failed to meet Grade V water quality standard, accounting for 4.3%, 3.6% and 7.9% of the total respectively. Major pollutants were ammonia nitrogen, petroleum and COD.

The water quality in low, level and high water seasons was all good, with 83.7%, 80.1% and 82.6% of all the sections monitored meeting or superior to Grade III standard, up by 0.8, 2.1 and 0.6 percentage points compared with that of the previous year. The river sections failed to meet Grade III national water quality standard mainly occurred in the districts of Banan, Changshou, Yubei and Wanzhou with 87.5%, 57.1%, 40.0 and 38.5% of the total sections exceeding national water quality standard.

8.1.2 Water quality of the backwater in sensitive areas

A total of 60 river sections were established in 31 rivers of 9 districts (counties), one district (county), 5 rivers and 11 sections more than in 2004. The monitoring covered 11 items such as water transparency, water temperature, pH value, dissolved oxygen, permanganate index, BOD₅, total nitrogen, ammonia nitrogen, nitrate, chlorophyll a and total phosphorus.

● Water quality

Six items including pH value, dissolved oxygen, permanganate index, BOD₅, ammonia nitrogen, and total phosphorus were employed to evaluate water quality.

The evaluation findings showed that the overall surface water quality of the backwater in sensitive areas of the migration resettlement areas was quite good in 2005. A total of 52 river sections met or were superior to Grade III national water quality standard, taking up 86.7% of the total, down by 1.1 percentage points compared with that of 2004. The amount of sections meeting Grade IV, V or inferior to Grade V standard was 3, 2 and 3 respectively, accounting for 5.0%, 3.3% and 5.0% of the total respectively. Major pollutants in the water were BOD₅, total phosphorus and ammonia nitrogen.

The percentage of river sections with water quality meeting or being superior to Grade III water quality standard was 87.2%, 81.1% and 93.0% in March, April and May, up by 4.4, 5.5 and 3.4 percentage points compared with the same period of the previous year. The sections with relatively poor water quality were mainly in Wanzhou District, Fuling District and Wushan County.

● Nutrition status of the water bodies

Five items including chlorophyll a, total phosphorus, total nitrogen, water transparency and permanganate index were employed to evaluate the nutrition status of the water body.

The monitoring results showed that the water body of 16 river sections was under eutrophication, accounting for 26.7% of the total. Among them, 11 were under slight eutrophication, 4 under intermediate eutrophication and 1 under severe eutrophication, accounting for 18.3%, 6.7% and 1.7% of the total respectively. Six sections were under poor nutrition and 38 sections were under medium nutrition, taking up 10.0% and 63.3% respectively. The comprehensive nutrition status index of the water bodies ranged from 20.96 to 72.53.

8.1.3 Water quality of drinking water sources

A total of 98 monitoring sites were set up in all major centralized drinking water sources of Class I towns in 15 districts (counties), 14 sites more than in 2004. The evaluation contents covered the basic water environmental items including pH value, dissolved oxygen, permanganate index, BOD₅, ammonia nitrogen, total phosphorus, copper, zinc, fluoride, arsenic, cadmium, mercury, hexavalent chromium, lead, iron, manganese, cyanide, volatile phenol, petroleum, anion surfactant and sulfide, sulfate, chloride and nitrate totaling 24 items.

The monitoring results indicated that in 2005, the water quality of the concentrated drinking water sources in the migration resettlement areas was quite satisfactory with the quality of 95.9% drinking water sources meeting or superior to Grade III water quality standard. Compared with the previous year, the proportion of sections meeting the functional requirements for drinking water source reduced by 4.1 percentage points. To be specific, the proportion of sections meeting Grade I and III water quality standard decreased by 4.0 percentage points and 0.1 percentage points respectively while the proportion of sections meeting Grade II quality standard remained the same as in 2004.

8.2 Environmental Air Quality Monitoring

The monitoring of environmental air quality of the migration resettlement areas was mainly composed of the monitoring of urban air quality and precipitation quality.

8.2.1 Air quality

A total of 31 air quality monitoring sites were established in 15 districts (counties) and 32 dust monitoring sites were established in 14 districts (counties). The key monitoring items included sulfur dioxide (SO₂), nitrogen dioxide (NO₂), total suspended particles (TSP) and dust. The Ambient Air Quality Standard (GB3095－1996) was applied in the evaluation of the environmental air quality.

Monitoring results showed some improvement of urban air quality in the migration resettlement areas in 2005. The comprehensive air pollution index went down by 5.0%.

The annual average concentration of sulfur dioxide in 2005 was 0.048 mg/m³, meeting Grade II national air quality standard. The daily average concentration of SO₂ was 0.003~ 0.276 mg/m³ with 1.4% of the total failing to meet national air quality standard. The highest daily average level of SO₂ was 1.84 times of the standard value. Among the 15 districts (counties) monitored, the annual average level of sulfur dioxide of 10 districts (counties) met Grade II air quality standard, accounting for 66.7% of the total.

The annual average concentration of nitrogen dioxide in 2005 was 0.027 mg/m³, meeting Grade II national air quality standard. Its daily average level ranged from 0.001 to 0.170 mg/m³, and 0.1% of the total failed to meet the national daily average standard. The highest daily average concentration was 0.42 times higher than the standard value. The annual average concentration of nitrogen dioxide in the air of all the 15 districts (counties) met Grade II national air quality standard.

The annual average concentration of total suspended particles (TSP) in 2005 was 0.148 mg/m³, meeting Grade II national air quality standard. Its daily average level ranged from 0.003 to 0.583 mg/m³, 2.2% of the total failed to meet the national daily average standard. The highest daily average level was 0.94 times higher than the standard. Among the 15 districts (counties) monitored, the annual average level of TSP of 14 districts (counties) met Grade II air quality standard, accounting for 93.3% of the total.

The annual average level of dust was 6.42 ton/km2·month, 0.52 times higher than the reference standard. The peak amount was 1.26 times higher than the standard value. Among all the 14 districts (counties) monitored, only Shizhu, Wulong County and Fengdu County failed to meet relevant national standard, taking up 21.4% of the total.

8.2.2 Precipitation quality

In 2005, 18 precipitation quality monitoring sites were set up in 15 districts (counties). A total of 846 precipitation samples were collected. Among them, 472 were acid rain samples with the frequency of 55.8%. The amount of acid rain accounted for 59.5% of the total precipitation, up by 1.6 and 12.4 percentage points compared with that of the previous year. The pH value of the precipitation tested ranged from 3.40 to 8.60, with an averaging of 4.58. Among all the 15 districts (counties) monitored, the annual average pH value of 9 districts (counties) was under 5.60, accounting for 60.0%.

8.3 Monitoring of Acoustic Environmental Quality

The monitoring of acoustic environmental quality in the migration resettlement areas included the monitoring of regional environmental noise, traffic noise and functional area noise. The evaluation work complies with the Standard for Urban Regional Environmental Noise (GB3096－93).

8.3.1 Regional environmental noise

A total of 1,643 monitoring grids were established in the towns of 15 districts (counties), covering 106.69 km2 of established urban area.

Monitoring results showed that the overall regional environmental acoustic quality was under slight pollution in 2005 with the equivalent sound level of 56.2 dB. Among all the districts (counties) monitored, the equivalent sound level of Kaixian County was the highest at 63.1 dB followed by Fengjie County at 62.4 dB. Banan District was the lowest at 53.3 dB. The source of noises was mainly from social life and domestic noises, accounting for 60.3% of the total. Traffic noise took the second, taking up 26.7%. Among the 1,643 monitoring grids, 1,197 grids met relevant national noise standard, accounting for 72.9%. The grid noise up-to-standard rate of Class I, II, III and IV region was 29.3%, 74.2%, 93.8% and 88.4% respectively. Banan District enjoyed the highest grid noise up-to-standard rate at 97.9% while Fengjie the lowest at 27.0%. Among the 15 districts (counties), only 2 enjoyed relatively good regional acoustic environment, accounting for 13.3% of the total.

8.3.2 Traffic Noise

In 2005, a total of 135 road sections were set up in 15 districts (counties) for the monitoring of traffic noise, covering a total length of 180.56 km.

Monitoring findings indicated that the overall road traffic acoustic quality was relatively good with average equivalent sound level being 69.0 dB. The average traffic flow was 1,169 vehicles/hour; and the total length of trunk road with equivalent sound level over 70 dB was 54.38 km, accounting for 30.1% of the total monitored length. 10 districts (counties) out of the 15 had rather good traffic acoustic environment, taking up 66.7% of the total.

8.3.3 Noise of functional areas

In 2005, 35 monitoring sites were set up in the towns of 15 districts (counties) to monitor the environmental noise functional areas, covering an area of 79.43 km2.

The findings showed that daytime and nighttime equivalent sound levels of the functional areas was 57.4 dB and 48.3 dB respectively, and the equivalent sound level in both the daytime and nighttime was 57.7 dB. 21.1% of the daytime hours and 36.8% of nighttime hours could not meet the national hourly noise standard. The equivalent sound level of all regions met relevant national noise standard for both daytime and nighttime with the exception of that (59.1 dB) of Class IV region during nighttime, which was 4.1 dB higher than the standard.