Marine Water Quality

In 2006, most of the coastal sea areas experienced good water quality despite continued severe pollution in some areas. Water quality of high sea areas remained in good condition.

67.7% of the coastal sea areas in China had water quality at Grade I or II standard, up by 0.5 percentage points than the previous year; 8.0% experienced Grade III water quality, down by 0.9 percentage points; and 24.3% witnessed water quality of Grade IV or failed to meet Grade IV, an increase of 0.4 percentage points.

Distribution of Water Quality in Coastal Sea Areas Nationwide in 2006

In terms of coastal seawater quality of the four major sea areas, the South China Sea and the Yellow Sea enjoyed overall good water quality, the offshore water was slightly polluted in the Bohai Sea, and East China Sea suffered from medium level of water pollution.

The Bohai Sea 69.6% of offshore water met Grade I or II standard, up by 3.6 percentage points than that of 2005; 21.7% was of or worse than Grade IV standard, up by 2.5 percentage points. The major pollutant factors were inorganic nitrogen, activated phosphate and petroleum related substances.

The Yellow Sea 83.7% of offshore water met Grade I or II standard, a decrease of 5.2 percentage points than that of 2005; 6.1% was of or worse than Grade IV standard, down by 5.0 percentage points. The major pollutant factors were inorganic nitrogen, pH and activated phosphate.

Sketch Map of Water Quality in China's Coastal Sea Areas in 2006

Coastal Water Quality of the Four Major Sea Areas

Among the nine major bays, the Yellow River Mouth and Beibu Gulf enjoyed good water quality with 80% meeting Grade I or II standard. Jiaozhou Bay suffered from slight pollution with 75% of water of Grade I or II standard. Minjiang Mouth was subject to medium level pollution with 50% of water at Grade II and IV standard each. Hangzhou Bay, the Yangtze River estuary, Liaodong Bay, the Pearl River Mouth and Bohai Bay both suffered from heavy pollution with less than 40% of the water of Grade I or II standard.

Ratio of Grade I and II Quality of water in Major Bays Ratio of IV and Inferior to IV Grade of water in Major Bays

Among the nine major bays, the Yellow River Mouth and Beibu Gulf enjoyed good water quality with 80% meeting Grade I or II standard. Jiaozhou Bay suffered from slight pollution with 75% of water of Grade I or II standard. Minjiang Mouth was subject to medium level pollution with 50% of water at Grade II and IV standard each. Hangzhou Bay, the Yangtze River estuary, Liaodong Bay, the Pearl River Mouth and Bohai Bay both suffered from heavy pollution with less than 40% of the water of Grade I or II standard.

Sediment Environment of the Coastal Areas

The sediment environment of coastal areas was rather good on the whole with low comprehensive potential ecological risk caused by pollution. However, the sediment in certain parts of the sea areas was subject to pollution of DDT, PCB and arsenic, and the pollution level of PCB in the sediment was somewhat aggravated with large area affected.

Seashell Pollution of the Coastal Area

In 2006, China furthered the implementation of the monitoring plan of mussel in coastal regions, bringing a variety of mussels including Ruditapes philippinarum, clam, Mactra veneriformis Reeve, Mytilus edulis, Perna uiridis, Scapharca subcrenata, Sinonovacula constricta and Saccostrea cucullata under monitoring. Years of monitoring results showed that the overall residue level of DDT, lead, arsenic, cadmium and petroleum hydrocarbon in the bodies of various kinds of mussels in coastal areas was decreasing on the whole with a sharp drop of DDT in particular.

Red Tides

The year 2006 saw 93 cases of red tides in all the sea areas, up by about 13% than the previous year and involving an area of 19,840 km² in accumulation, about 27% less than that of 2005.

Red tides involving an area over 100 km² each numbered 31, involving an aggregated area of 18,540 km², accounting for 33% and 93% of the incidence and aggregated area of red tides respectively. Red tides covering an area over 1,000 km² numbered 7.2 times less than that of 2005 and down by 51% in terms of aggregated area.

The red tide made a concentrated appearance with high incidence in the sea area of East China Sea, accounting for 68% and 76% of all the sea areas in terms of number of incidence and areas plagued. The red tides that cover a large area mainly occurred in the sea area of BohaiBay, sea area out of the Yangtze River estuary and central and southern part of Zhejiang Province.

The major biological species triggering the red tides are toxic algae of Karenia mikimotoi, Phaeocystis globosa and avirulent ones like Skeletonema costatum, Prorocentrum triestinum and Noctiluca scintillans. There were altogether 41 cases of red tides caused or concerted caused by toxic algae, covering a total area around 14,970 km² in aggregation, taking up 44% and 75% of the number of cases and areas of red tides of the whole year respectively, which is at the same level of that of 2005.

Large-scale Red Tides Occurring in China’s Sea Areas in 2006

Measures and Actions

【Blue Sea Action Plan in Major Sea Areas】Various works under the Blue Sea Action Plan in the Yangtze River Estuary and Adjacent Sea Areas were carried out steadily. By the end of 2006, a string of works including the survey of the environmental situation of the Yangtze River estuary, pollution source inspection, monitoring of pollutants influx into the sea and checkup and appraisal of marine ecological environmental status have been conducted, thus laying the foundation for the fully launching of the Blue Sea Action Plan.

The fundamental work for the implementation of the Blue Sea Action Plan in the Pearl River Estuary and Adjacent Sea Areas has got along smoothly. In specific, the on-the-site survey work of the synchronized river and sea pollutants influx into the sea and marine ecological environment of the Pearl River estuary and adjacent sea areas during the flood and level period respectively have been completed, and the monitoring stations for continued monitoring of land-based non-point pollution source and dry deposition have also been established in 2006.

【Establishment of Marine Protected Areas】In 2006, the State Council approved the inclusion of Shandong Binzhou Beike Bank and Wetland Protected Area into state level marine nature reserve, adding the total number of state level nature reserves up to 29. Presently, there are 149 marine nature reserves nationwide at all levels, covering a total area of 37,584 km² (including the area of the coastal lines covered) and registering 1.2% of the total sea area under jurisdiction of China. Marine nature reserves were established in all the 11 coastal provinces (autonomous regions and municipalities), and the establishment of marine special protected areas were also advancing in fast pace. By the end of 2006, altogether 7 marine special protected areas had been established across the country, among which 4 were state level marine special protected areas.