4. RESULT INTERPRETATION

The purpose of contamination assessment is to identify any need for site remediation so as to ensure that the current/future occupants of the site, buildings or services, and plants and animals, would not be exposed to risks which could be avoided.

For the assessment of soil results, the reader should refer to the relevant Practice Note for Professional Persons on contaminated land management issued by EPD. For the evaluation of groundwater results, some kind of risk assessment is essential although groundwater is seldom used for drinking purpose in Hong Kong. It is prudent to assess the risk that contaminated groundwater may pose to the general public, future users of the site, construction workers, etc. and the adverse effect the contaminated water may have on the fabric of buildings or underground services, and determine if some remediation or precautionary measures are necessary. This usually entails a simple risk assessment which identifies:

(i) possible sources of contamination;

(ii) potential "receptors" of contamination;

(iii) potential migration pathways of the contaminants;

(iv) exposure routes and scenarios; and

(v) contaminant concentrations at possible points of exposure.

Exposure point concentrations are then compared with the allowable levels of contamination for the "receptors" to determine if remediation or other measures are required.