Site investigation and assessment includes site environmental investigation and risk assessment, and risk assessment is divided into health risk assessment and ecological risk assessment. Because the development of ecological risk assessment technology is immature and difficult, site assessment generally only carries out health risk assessment, so the risk assessment in this paper refers to health risk assessment. Environmental impact assessment is divided into planning environmental impact assessment and construction project environmental impact assessment according to the evaluation object.
1. The evaluation objective and process are different.
In terms of evaluation objectives, Article 2 of the Environmental Impact Assessment Law stipulates that the term "environmental impact assessment" as mentioned in this Law refers to the methods and systems for analyzing, predicting and evaluating the possible environmental impacts after the implementation of planning and construction projects, putting forward countermeasures and measures to prevent or mitigate adverse environmental impacts, and tracking and monitoring them. Site investigation and evaluation is the process of identifying and evaluating site environmental pollution or potential site environmental pollution, that is, investigating past and present activities of the site, analyzing and evaluating site environmental conditions and environmental risks. Therefore, environmental impact assessment is to evaluate the impact of future construction projects on the surrounding environment.
Site investigation and evaluation is to evaluate the health risk of pollution to the surrounding people in the future land use through the investigation of the existing pollution situation of the site.
In the process of evaluation, according to the characteristics of the environment, the environmental impact assessment of construction projects can usually be further decomposed into the evaluation of different environmental elements (atmosphere, surface water, groundwater, noise, ecology, electromagnetic radiation, etc.). ). Specifically, environmental impact assessment is generally divided into three stages:
The first stage is the stage of preparation, investigation and work planning.
The second stage is the stage of analysis, demonstration, prediction and evaluation.
The third stage is the preparation stage of environmental impact assessment documents.
The field investigation and evaluation also includes three independent in-depth stages:
The first stage is the preliminary identification of site pollution, mainly through talks and field visits, collecting and analyzing the past and present use of the site, especially the relevant information of pollution activities, and identifying and judging the possibility of site environmental pollution; When necessary, it is necessary to conduct sampling analysis.
The second phase of the site environmental investigation will further confirm whether the site is polluted.
In the third stage, supplementary sampling analysis and data query are the main methods for site investigation and evaluation, which can meet the requirements of risk assessment, investigation and testing of parameters needed in the process of soil and groundwater remediation, and carry out health risk assessment of contaminated sites. Risk assessment procedures for contaminated sites include hazard identification, exposure assessment, toxicity assessment, risk characterization and determination of recommended remediation target values for soil remediation. The whole evaluation process also includes three stages, but the working procedure of environmental impact assessment is a sequential structure, and the end point is the environmental impact report.
The working procedure of on-site investigation and evaluation is an optional structure, and each stage can be terminated. Whether the site investigation and evaluation needs to go from one stage to the next depends mainly on the evaluation results of the previous stage, that is, the site pollution situation and the requirements of interested parties.
2. The implementation time and the responsible subject are different. In terms of the implementation time, Article 9 of the Regulations on Environmental Protection Management of Construction Projects stipulates that the construction unit shall submit the environmental impact report of the construction project at the feasibility study stage of the construction project, and the construction project without feasibility study shall be submitted for approval before the start of construction. There is no restriction between environmental impact assessment and the completion of land transfer, and there is no fixed order. However, the investigation and evaluation of contaminated sites should usually be carried out before land transfer to clarify the responsible subject. If we want to trace back the land reserve units and the units and individuals that caused the site pollution after the land transfer, it is extremely difficult and does not have maneuverability, forming a "triangular debt" problem in the field of similar engineering construction, which is extremely difficult to solve. In addition, there will be land leveling (four links and one leveling) before land transfer in China. Before this, if pollution investigation and environmental risk assessment are not carried out, the pollution situation is clarified and control measures are taken, which will easily lead to the transfer and expansion of pollution.