|
2.
SITE APPRAISAL
The purpose
of a site appraisal is to identify current and historical
uses of the site which have the potential for causing contamination.
By the nature of the industries themselves and their related
activities, petrol filling stations, boatyards and vehicle
repairing/dismantling workshops have a significant potential
for causing contamination. The information gathered at this
stage of the assessment will assist in planning the site investigation.
A desktop
study should be carried out to identify the activities that
have been carried out at the site. Table 2.1 provides a list
of activities and installations associated with the above-mentioned
industries that have potential for causing contamination.
The project proponent should check against this list for activities
practised at the site. If any of the activities listed in
Table 2.1 has been or is being carried out at the site, it
is most likely that the site has been contaminated. A site
inspection or 'walkabout' should also be undertaken to identify
any physical clues of contamination.
Table
2.1 Activities and Installations with the Potential to
Cause Contamination
| Petrol
Filling Station |
Boatyard
|
Vehicle
Repairing/ Dismantling Workshop
|
|
Vehicle
fuelling
Vehicle
servicing
|
Coating/steel
treatment
Fitting
out/repair
Breaking
Waste
disposal on site
Process
pipework/pump repair
Drainage
system and soakaway system
Fuel
storage/pipework
Electrical
transformer areas
Chemical
storage
|
Vehicle
fuelling
Vehicle
servicing
Painting
Vehicle
dismantling
|
It is
also important to study the past history (e.g. accident records,
change of land use etc.) of the site in relation to possible
land contamination. Table 2.2 contains a list of the typical
sources of information used to assess site histories.
Table
2.2 Typical Sources of Information Used to Assess Site
Histories
|
Historical
Information Sources
|
|
Maps
& Plans
Building
layout drawings
Company
records
Previous
site investigations
Planning
registers
Land
registers
Historical
aerial photographs
Consultation
with government departments (e.g. Planning Department,
Lands Department, Buildings Department, Environmental
Protection Department, Fire Services Department, Drainage
Services Department, Geotechnical Engineering Office)
|
The checklist
given in Annex A can be used to summarize the available background
information of the site including the size, nature, previous
records of contamination etc. It can also be used as a questionnaire
for collecting information from existing operators. The information
collected should be used to check against a set of criteria
described in Table 2.3 to decide on how the site investigation
should be devised to take into account the local circumstances
and whether a full-scale or simplified site investigation
should be conducted. If the answer to any one of the criteria
is "No", a full-scale site investigation will probably be
required (Section 3, Table 3.3). Otherwise, a simplified site
investigation with reduced number of sampling points may be
applicable subject to agreement with the EPD (Section 3, Table
3.3).
Table
2.3 Criteria for Adopting Full-scale or Simplified Site
Investigation
|
Criteria |
Yes/No
|
|
1. Length
of operation of the site is less than 5 years.
|
|
|
2. There
is practice of recording spill incidents or monitoring
chemical storage.
|
|
|
3. Waste
disposal is carried out in accordance with Government
requirements.
|
|
| 4. Absence
of underground storage tank on the site. |
|
| 5. Absence
of surface contamination indicators which include:
i) stained
areas;
ii)
uncontrolled chemical drum storage;
iii)
cracked concrete near storage of chemical drums;
iv)
unnatural colours and odours; and
v) abandoned
piping/mechanical components or cans.
|
|
|
|