Index > 4 Environmental remediation of radioactively contaminated sites >

4.4.5 Potential secondary environmental impacts (collateral damage)

The implementation of a remediation project may result in a variety of environmental impacts in addition to those resulting from the contamination itself. When a remediation strategy is selected, the impact of this strategy on the local environment may need to be evaluated (operational safety cases) to determine the net reduction in hazards, i.e., it will not be reasonable to cause more harm as a result of the remediation than by undertaking no remediation at the site. For instance, certain technologies, such as removal of topsoil or soil washing, may remove surface contamination at the cost of destroying the soil ecosystem [IAEA-2006b].

Environmental risk involves adverse impacts on ecological receptors located on-site or off-site due to significant disturbance to the site ecosystem and its surroundings as a result of remediation. Impacts to be considered will be:

  • Nuisances, for example noise, vibration, dust and traffic;
  • Impacts on water resources, for example surface and groundwater contamination;
  • Impacts on soils, for example, reduced fertility.

Depending on the size of the site, an area larger than the actual contamination may be required for installations, intermediate storage of wastes, etc. Removal, transport and disposal of residual wastes may result in environmental impacts and risks at locations other than those of the original contamination. There is, for example, little benefit in removing a contaminant that is well fixed on a low volume of soil, only to produce a high volume of aqueous wastes with the contaminant in a soluble or mobile form. In addition, the remediation techniques chosen may generate large quantities of secondary wastes and may pose risks of exposure to the public or operators that exceed the risks of quiescent contamination [IAEA-2006b].

Environmental risk arising from the implementation of remedial actions may also extend to possible impacts on natural resources, such as surface water, groundwater, air, geological resources or biological resources. The potential for environmental risk may be an important factor in decision making because some remediation technologies are more likely than others to produce adverse impacts on ecological receptors, including habitat disruption, or to generate damage to natural resources.