A Study on Sampling Strategy for Contaminated Soil Investigation
Date Issued
2005
Date
2005
Author(s)
Chen, Chih-Hao
DOI
zh-TW
Abstract
Three typical objectives of a sampling design for contaminated soil investigation are: (1) to identify the location of “hot spots”, (2) to estimate contamination levels, (3) to delineate the pollution patterns and range of contaminated sites. This research addresses the issue of suitability about the sampling strategy for above objectives.
In first case, objective of sampling is to determine where "hot spots" are present. Spatial analysis method is presented to assess the capability of searching for hot spots of sampling strategy, includes Spatial Simulated Annealing (SSA) and grid sampling strategy. The results indicate the Spatial Simulated Annealing is better than grid sampling design when searching for hot spots. Grid sampling design has the higher miss rate than Spatial Simulated Annealing when deal with the same pollution site with same sampling density.
When sampling strategy were aimed at estimating average concentrations or total amounts of pollutants in environmental media, Statistics theory provides a basis for balancing decision uncertainty with available resources. This section discusses optimize the design for obtaining data by specify limits on decision errors stage by stage. The results reflect that assessing sample size needed for investigation by well-planned confidence could make the outcome achieve sampling objective with required performance.
To delineate the pollution patterns and range of contaminated sites, two approaches are presented: ordinary kriging (OK) and sequential indicator simulation (SIS) approach, and illustrated the characteristics by case studies. Mapping the values of continuous soil attributes by kriging perform well to assist judgmental sampling, while the simulation-based approach provide assessing the uncertainty about the value of soil properties at unsampled locations, and thus incorporate this assessment in subsequent decision-making processes.
Subjects
土壤污染
採樣策略
空間模擬退火法
地理統計
Soil contamination
Sampling Strategy
Spatial Simulated Annealing
Geostatistics
Type
thesis