series of operational guidelines for site pollution investigation and evaluation,
including ASTME 1527 Standard Practice for Site Environmental Assessments:
Phase I Site Environment Assessment Process, ASTME 1528 Standard Practice
for Site Environmental Assessments: Transaction Screen Process, ASTME 1903
Standard Practice for Site Environmental Assessments: Phase II Site
Environment Assessment Process, ASTMD 1452 Standard Practice for Soil
Exploration and Sampling, and ASTMD 5092 Standard Practice for Design and
Installation of Groundwater Monitoring Wells. All these standards provide a
reference for groundwater environmental investigation and assessment.
With the formulation of investigation and pre-assessment policies and guidelines, targeted code for risk assessment of contaminated sites have also been
established. In 1995, the U.S. standards and material measurement institutes
proposed the Risk Assessment and Corrective Action Process for Petroleum
Release Sites which was revised in 2002. The technical process typically consists of five steps: initial site assessment, site characterization and interim
actions, tier-1 risk assessment, tier-2 risk assessment, and tier-3 risk assessment.
The initial site assessment gathers information on soil and groundwater pollution by means of site investigation and soil sampling to determine the main
contaminants, contaminated environmental media, affected environmental
receptors, and pathways of pollution. Site characterization is necessary to
ascertain the extent of groundwater pollution based on initial site assessment,
and determine the need for actions according to the degree of threat to humans
and environmental receptors. Tier-1 risk assessment calculates the risk-based
screening levels (SLs) for groundwater, and compares them with pollutant
concentration levels identified in the site investigation to determine whether a
site is exposed to pollution. Tier-2 risk assessment is specific to sites and
exposure points, and tier-3 risk assessment is more complicated and may
involve software-based simulation of pollutant migration and transformation.
This corrective action process has been recognized by the International
Organization for Standardization (ISO) and other countries.
2. United Kingdom
In 2000, the UK Environment Agency set out a framework for site investigations based on risk assessment, which consists of three steps: preliminary
investigation, exploratory investigation, and focus investigation. The preliminary investigation includes desktop study and site walkover survey to identify
potential site risks and develop site-specific conceptual model based on obtained
information. By way of investigation and sampling, the exploratory investigation is intended to clarify the source-pathway-receptor route and revise the
conceptual model. The focus investigation refers to full investigation, sampling
and analysis (including invasive and non-intrusive investigations) to further
refine the established conceptual model.
3. Japan
In 1999, the Japanese Ministry of the Environment developed the Survey and
Countermeasures Guidelines for Soil and Groundwater Pollution based on the
4
1 Introduction
including ASTME 1527 Standard Practice for Site Environmental Assessments:
Phase I Site Environment Assessment Process, ASTME 1528 Standard Practice
for Site Environmental Assessments: Transaction Screen Process, ASTME 1903
Standard Practice for Site Environmental Assessments: Phase II Site
Environment Assessment Process, ASTMD 1452 Standard Practice for Soil
Exploration and Sampling, and ASTMD 5092 Standard Practice for Design and
Installation of Groundwater Monitoring Wells. All these standards provide a
reference for groundwater environmental investigation and assessment.
With the formulation of investigation and pre-assessment policies and guidelines, targeted code for risk assessment of contaminated sites have also been
established. In 1995, the U.S. standards and material measurement institutes
proposed the Risk Assessment and Corrective Action Process for Petroleum
Release Sites which was revised in 2002. The technical process typically consists of five steps: initial site assessment, site characterization and interim
actions, tier-1 risk assessment, tier-2 risk assessment, and tier-3 risk assessment.
The initial site assessment gathers information on soil and groundwater pollution by means of site investigation and soil sampling to determine the main
contaminants, contaminated environmental media, affected environmental
receptors, and pathways of pollution. Site characterization is necessary to
ascertain the extent of groundwater pollution based on initial site assessment,
and determine the need for actions according to the degree of threat to humans
and environmental receptors. Tier-1 risk assessment calculates the risk-based
screening levels (SLs) for groundwater, and compares them with pollutant
concentration levels identified in the site investigation to determine whether a
site is exposed to pollution. Tier-2 risk assessment is specific to sites and
exposure points, and tier-3 risk assessment is more complicated and may
involve software-based simulation of pollutant migration and transformation.
This corrective action process has been recognized by the International
Organization for Standardization (ISO) and other countries.
2. United Kingdom
In 2000, the UK Environment Agency set out a framework for site investigations based on risk assessment, which consists of three steps: preliminary
investigation, exploratory investigation, and focus investigation. The preliminary investigation includes desktop study and site walkover survey to identify
potential site risks and develop site-specific conceptual model based on obtained
information. By way of investigation and sampling, the exploratory investigation is intended to clarify the source-pathway-receptor route and revise the
conceptual model. The focus investigation refers to full investigation, sampling
and analysis (including invasive and non-intrusive investigations) to further
refine the established conceptual model.
3. Japan
In 1999, the Japanese Ministry of the Environment developed the Survey and
Countermeasures Guidelines for Soil and Groundwater Pollution based on the
4
1 Introduction