Soil Contamination and Remediation for Construction Contractors
Published on 01/27/2009
A construction site's ground cover is sometimes contaminated with toxic materials, posing a hazard to individuals working on the site and the environment in general. For many contractors, contaminated soil is a difficult problem to address. As a result, California's Department of Transportation (Caltrans) has identified procedures for contaminated soil management and remediation that should be taken by contractors in order to minimize the detrimental effects of toxic materials found in a site's ground cover. Proper management of contaminated soil will help prevent it from polluting the storm drain system or watercourses.
If it is suspected that a construction site is contaminated during the project's planning stages, contractors must take steps to determine if the site actually is polluted. Remember that while the ground cover may have become polluted prior to the start of construction, it is the responsibility of the contracting firm to remove the contaminated soil and protect laborers from the negative effects of the pollutants. This requirement has legal precedent, as courts have handed down rulings in the past stating that contractors are liable for contaminated soil remediation costs even if they are unaware that they are moving contaminated soil on a site.
Often, soil pollution at a site is the result of pre-job spills, illegal dumping, the leaking of underground storage tanks, or aerially deposited lead (ADL). It is important for contractors to perform a thorough examination of the construction site prior to beginning work. So, how can contractors determine if a site is polluted? Frequently, the plans themselves document where areas of soil contamination are located. Contractors can also find contaminated areas by researching the site's past uses and taking the time to notice areas where the soil is discolored and odorous. To be absolutely sure about the contamination of the site, the contractor can submit soil samples for testing at a local laboratory.
In the event that the soil is contaminated, certain remediation measures must be taken to ensure that workers and the public at large are not affected by the polluted material. Before work on the site begins, those working on the site are required by state and federal law to complete a hazardous waste operation training seminar. This training course will facilitate safe work practices and enhance the ability of individuals to identify contaminated soil and sources of contamination.
Generally, there are three approaches to cleaning up contaminated soil. First, soil can be excavated and then treated or disposed in a manner in accordance with state and federal statutes. Second, the soil can be treated in place. Third, the contaminated soil can be left in the ground and contained to ensure that it does not come into contact with vegetation, animals and humans.
Following proper training, the best management practices to be taken depends on the approach to remedying contaminated soil. In instances when it is decided that the soil should be excavated for another purpose, contractors and subcontractors are required to undertake certain handling procedures to ensure that the chemicals polluting the soils are contained. For example, the excavation, transportation, and placement of ADL contaminated material must not create any visible dust and the air quality must be monitored in the areas where the soil is being excavated. Furthermore, any transportation of contaminated soil must be done by a licensed hazardous waste hauler. Another concern for contractors is how to protect polluted soil from encountering the flow of water, which can transport contaminated soil particles to untainted parts of the work site or, even worse, surrounding communities. Thus, it is essential to store the hazardous material away from water sources and to secure it from run-off with berms and tarps.
While it may seem as if the moment soil becomes contaminated it is rendered useless, this is not the usually the case. Depending on the contaminants, some soil may be recycled and applied to other construction uses. When soil is polluted by ADL, the soil may be use as embankments and/or backfill if permitted by the project's contract provisions. Additionally, some nonhazardous petroleum and pesticide contaminated soils can be reused. Often, soil polluted with petroleum can be used as an additive in hot mix or a component in the material used for road bases and subbases. Even though soil remediation is a costly process, the reusability of some contaminated soils allows contractors to recuperate a part of the expenses. They can either reuse the material on the site from which the contaminated material was procured or reprocess it to use on another project. Moreover, recycling helps contractors avoid the extensive costs of disposing of the material at a Class I or Class II disposal facility. On average, disposing of contaminated soil costs $350 per yard.
Contaminated soil can be a serious hazard to individual health and the environment. However, California and the federal government have instituted measures that prevent the spread of hazardous soil from a construction site. While there are a number of methods for performing soil remediation, the approach to remediation must coincide with nature of the job site and the needs of the project. In the end, it is essential for contractors to address the issue before and during construction. A failure to do so will produce negative effects for both the community and the contractors involved.
