Land contamination can occur as a result of poor environmental management and waste disposal practices, use of contaminated fill to reclaim or level the site, leaking underground storage tanks and accidental spills in industrial, agricultural or commercial activities.
There are specific industries and common land uses which have been associated with site contamination. Some of the activities include: service stations, chemical plants, tanneries, cattle dips, fuel and oil storage, foundries and landfills.
Contaminated land management legislation and guidelines place obligations upon local governments, owners and occupiers relating to the identification, notification and management of contaminated land.
Contaminated site assessments are generally undertaken for the following reasons:
- Change in the land use (e.g. from industrial to residential)
- Property transactions
- Conformance with notices or orders by government authorities (e.g. DECCW) or the courts
- Due diligence purposes
The typical staged approach of contaminated site investigations and management is:
- Stage 1 preliminary site assessment: Essentially involves a walk-over inspection of the site, interviews with relevant parties such as site management, owners and government authorities, review of site history and records and sometimes limited soil sampling. This assessment indicates whether there is a risk of contamination at the site, the potential contaminants and possible locations of the contaminants and whether a more detailed investigation (Stage 2) is required
- Stage 2 detailed site assessment: This assessment involves a comprehensive soil (and groundwater) sampling program to establish the extent of contamination for the range of potential contaminants identified in Stage 1. The detailed site assessment report assesess the risks posed by the contamination, and indicates whether the level of contamination is within acceptable criteria, or whether remediation or management is required
- Stage 3 Remedial Action Plan (RAP): The RAP details the site remediation strategies, contaminated area(s), treatment or off-site disposal details, validation of remediated areas and imported fill, environmental management controls and health & safety plans for the remediation project
- Stage 4 site remediation: Site remediation involves the implementation of the RAP, which should be project managed and monitored by experienced and competent persons.
- Stage 5 validation: The validation report presents the results of the validation sampling which demonstrates that the remediation has been completed. The Hibbs and Associates personnel are qualified and experienced to provide the following services for the assessment and remediation of contaminated sites:
- Site contamination assessments
- Preparation of remedial action plans (RAP) and site management plans
- Validation sampling and reporting
- Remediation project management
- Advice on remediation technology
- Environmental air, noise and water monitoring