Land Contamination

The Cause

In Canterbury, land has been contaminated by

• timber treatment chemicals at several timber sites
• substances that were more toxic or persistent than initially thought, such as DDT, residuals of which are still detectable in topsoil through a large part of the Plains and Downs
• heavy superphosphate use, which has resulted in raised levels of cadmium
• leaks and spills associated with the manufacture, transportation, storage, use and disposal of many substances

The Options

Environment Canterbury is involved in developing nation and regional initiatives to address land contamination, and could adopt any of the following site specific options within a regional plan:

1. Provide information on appropriate use and disposal options for hazardous substances, as well as information on contaminated sites and possible ways of cleaning up these sites.
   
   This makes useful information accessible, but has associated costs and potential problems with voluntary compliance.
    
2. Prepare guidelines for the management of hazardous substances such as containment requirement.
    
3. Continue to prepare a register of potentially and confirmed contaminated sites and identify priorities for further investigations.
   
   This enables us to assess sites and prioritize action, but there may be liability issues related to the Privacy Act and dissemination of information.
    
4. Encourage and assist  industry to develop or adopt existing codes of practice or guidelines on appropriate use, storage, disposal, and transportation of hazardous substances.
   
   Industry "ownership" of such substances may help in adherence, but it will still be on a voluntary basis.
    
5. Prepare regional rules to control the use of high-risk hazardous substances.
   
   This provides control in that appropriate actions will be defined and compliance could be monitored, but it could be difficult and costly to implement, particularly if there is resistance from users.
    
6. Lobby government to restrict or ban highly hazardous substances, or to introduce a hazardous substance.
   
   This has a high level of certainty of action, but it will restrict opportunities and impose costs on users.
    
7. Establish regional services and facilities to collect, store and dispose of unwanted hazardous substances.
   
   This will reduce the chance of on-going environmental hazards and increase community awareness in a positive manner. However, because the scale of the problem is currently unknown, associated costs cannot be predicted and the Regional Council may end up assuming liability and responsibility for the substances collected.