Huang Yeru, Zhou Li, Shao Dingding, Di Yian,Shi Shuangxin, Ge Haihong
Sino-Japan Friendship Center for Environmental Protection

The Stockholm Convention entered into force on 17 May 2004 after 50 nations ratified the document. The first meeting of the Conference of the Parties was held from 2–6 May 2005 in Punta del Este, Uruguay. In implementing the Convention, Governments will take measures to minimize and eliminate the production, import, export, disposal and use of POPs in order to reduce the release of POPs into the environment.

Among the important classes of persistent organic pollutants (POPs) are many families of chlorinated aromatics, including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and –furans (PCDDs/PCDFs) and different organochlorine pesticides (e.g. DDT and its metabolites, toxaphene, chlordane, etc.). Some are accidental by-products of combustion or the industrial synthesis of other chemicals (e.g. the PCDD/Fs) not produced deliberately. Many have been synthesized for industrial uses (e.g. PCB, chlorinated paraffin’s) or as agrochemicals (e.g. DDT, lindan, chlordane). These pesticides have been extensively used worldwide after World War II for crop protection and disease vector control, with considerable success. However, like other POPs, these pesticides are organic compounds that, to a varying degree, resist photolytic, biological and chemical degradation making them remain intact in the environment for long periods, and becoming widely distributed geographically. The negative impact of these pesticides on agro-ecosystems, as well as on the environment and human health have become increasingly evident since the 1950s. At present, chemicals such as DDT, mirex and toxaphene are still being produced and used because of lack of cheap and effective alternatives in developing countries.

Being a large agricultural country, China has been a major producer and consumer of POP pesticides. In addition, DDT is still allowed to be used as pesticides for controlling mosquito which transmit malaria. The rapid socio-economic development during the past two decades in China has given rise to severe economic, environmental and health problems.

Data on POPs monitoring are not only basis for the design of effective measures for the reduction of POPs, but are used as a basis for evaluation of efficiency of the POPs treaty and related measures. In addition, the monitoring data can be used as basic information for selecting new POPs candidate substances that have properties similar to established POPs. Furthermore, insight into POPs and pollutants in general, as well as their effective prevention measures, will be facilitated by promoting and enforcing associations with other related domestic and foreign monitoring and investigation.

Since 2002, Sino-Japan Friendship Center for Environmental Protection had been joining the United Nations University’s project entitled “Environmental Monitoring and Governance: POPs in the East Coastal Hydrosphere”. The focuses of the monitoring during the three years were on 18 individual organochlorine pesticides (OCPs). The targeted compounds include α-BHC, β-BHC, γ-BHC, δ-BHC, p,p’–DDE, o,p’-DDE, p,p’–DDD, p,p”-DDD, p,p’-DDT, o,p’-DDT, hexachlorobenzene (HCB), heptachlor, trans-chlordane, cis-chlordane, aldrin, dieldrin, endrin, and mirex, etc.

The Haihe River valley is located in North China, comprising the Haihe River and Luanhe River system. The Haihe River system mainly consists of Zhangwei River, Ziya River, Daqing River, Yongding River, Chaobai River, North Canal, Ji Canal, as well as some plain drain flooded river course such as Douhai River, Majia River. In 2002, water samples were collected in Ziya River, Yongding river, Caobai River, Haihe River and Guanting Reservoir. Only α-BHC, β-BHC, γ-BHC, HCB and DDT were detected in some samples.

In 2003, more than 36 soil samples from Beijing, Shanghai, Nanjing and Guiyang, 10 sediment samples and 14 water samples from Baiyangdian Shallow Lake and 17 river samples from Luanhe River were collected and analyzed by gas chromatography-mass spectrometry. No POPs were detected in water samples from Luanhe River. Only HCB in the range of 1.1?2.2ng/L were found in all water samples collected in Baiyangdian Shallow Lake. In addition, HCB with a range of 0.1 to 2µg/kg existed in all soil and sediment samples. The levels of p,p’–DDT (0.1 to 12µg/kg) monitored in soil samples were much lower that the maximum contaminant level in Environmental Quality Standard for Soils (GB 15618-1995). At the same time, no heptachlor, aldrin, dieldrin, endrin could be detected in all samples in this study in 2003.

During 2004, more than 115 soil samples from Beijing, 23 sediment samples from Yongding River, Tonghui River and Chaobai River, and 14 water samples from Miyun, Guanting, Huairou, Shisanling, and Gaobeidian Reservoirs were collected and analyzed by gas chromatography-mass spectrometry. Sample preparations for soil and sediment samples were carried out by microwave assisted extraction (MAE) and accelerated solvent extraction (ASE). Only HCB in the range of 0.1?2.4ng/L were found in all water samples. Trans-chlordane, cis-chlordane, p,p’-DDE, p,p’-DDD and o,p’-DDD were detected in water sample collected in Gaobeidian Reservoir. The distributions of POPs in sediment samples collected were HCB 0.05~67.3mg/kg,chlordanes ND~0.190?mg/kg,p,p’-DDE ND~64.9µg/kg, p,p’-DDD ND~7.35µg/kg and DDTs ND~40.4µg/kg. The distributions of POPs in soil samples were HCB (113/115) ND~115µg/kg,chlodanes (20/115) ND~1.28 mg/kg,DDE (114/115) ND~1340µg/kg,DDD (95/115) ND~181µg/kg and DDT (96/115) ND~344µg/kg. No aldrine, dieldrin, endrin, teptachlor and mirex could be monitored in all samples in this investigation.