Analysis of the Regional Ecological Environment and Pollution Formation Mechanisms
Northeast China is the country's most important industrial base, and the development of the Northeast Old Industrial Base (NEOIB) was in many cases at the expense of the environment. This has created problems with respect to regional environmental pollution: (1) Industrial wastewater discharge has resulted in polluted surface water, and long term, high-level accumulation of contaminants in sediments; (2) Long-term deposition of atmospheric contaminants has caused significant regional environmental problems and threatened human health; and (3) Inappropriate water resource use regimes have contaminated sewage treatment areas, resulting in severe soil organic and inorganic pollution problems. Thus with respect to the environmental issues of NEOIB, it is of great practical significance for comprehensive revitalization of the old industrial base to address the mechanisms of pollution at the regional level, and to propose new pollution control and remediation methods.
Regional environmental pollution studies (REPS) focus on overall regional environmental problems; explore the nature of regionally-distributed contaminants and their sources at different spatial scales; assess links between local and global manifestations of pollution problems; identify pollutants and contaminated areas within the region as priorities for remediation efforts; and investigate the origin and proliferation of major contaminants and their sources within the region at different temporal scales. Other tasks of REPS are to analyze and predict micro- and macro-scale features of contaminants and to assess the mechanisms of contaminant transfer, transformation and mitigation. Research methods on the regional distribution of pollutants include the analysis of the occurrence of contaminants in different media using state-of-the-art environmental-chemical techniques; the collection of historical, geographical and climatic data related to contamination; and the interpretation of contaminant distribution via the application of geographic information systems. In addition, micro- and macro-scale transport and migration models for contaminants are also important means to reveal the origin and evolution of regional pollution.
Major research foci for regional environmental issues include the following: 1) Exploring the distribution of contaminants within the region using geographic surveys, geostatistics, and geographic information systems; and 2) Examining the formative mechanisms involved in the transport of pollutants via the use of pollution indices and environmental models.
Spatial and temporal distribution of NEOIB contaminants. It is recognized that the number of pollution sources changes significantly over time. The accumulation of toxic and hazardous contaminants in the NEOIB has been documented. We have identified the main toxic and hazardous contaminants released from industrial contaminant sources in the NEOIB.
Agricultural soil pollution. Utilizing agricultural soil surveys and polycyclic aromatic hydrocarbon (PAHs) analysis in the Shenfu sewage water-irrigated area, the spatial distribution of PAHs in soils of major contaminated areas was identified. We have ascribed soil PAH contamination to petroleum burning and wastewater irrigation. Through the analysis of heavy metals in the black soils in NEOIB, we found that cadmium is the element that is most potentially hazardous to soil health.
We also surveyed the water quality of important rivers in northeast China. We clarified pollution characteristics and the temporal evolution of aquatic contaminants in the Liaohe and Songhua Rivers and identified major problems of the aquatic environment in the NEOIB. We have analyzed the levels of contaminants, overall trends, and the spatio-temporal heterogeneity of water quality and also described combined effects of multiple pollutants including petroleum, CODMn, volatile phenols, ammonia and mercury in aquatic environments.
Environmental quality surrounding industrial and mining areas. In traditional industrial areas of the NEOIB such as the Huludao Zinc Plant, the Liaohe River Oilfield, the Xinchengzi Chemical Plant, the Benxi Iron and Steel Company and their surrounding areas, we have collected soil, water and air samples, and studied pollution emanating from large industrial enterprises. We have clarified the spatial distribution of contaminants such as Cd, Pb, PAHs and TPHs at these sites and demonstrated positive correlations between the degree of soil contamination and enterprise production activities. We have described the long-term spatial variation of petroleum and persistent organic pollutants (POPs) in Northeast China using mathematical models incorporating climatic and geographical data.
Figure 29: Spatial and temporal distribution of industrial pollutant sources in Northeast China from 1985 to 2005 (note: each data point represents 3 pollutant sources).
Figure 30:Standard load distribution and variation trends of industrial wastewater in Northeast China from 1985 to 2005