Contaminated Land
If land has been polluted, BRD's expertise in risk assessment can make sense of the numbers.
Once a soil sample has been analysed by a laboratory, the concentrations for up to a couple of hundred different chemicals are presented in a table. How do we understand all these numbers?
The first step to appreciate is that when assessing risk to human health from soil contamination it is considered on a suitable for use basis. In other words, whether the concentration of a particular chemical is of concern or not will depend upon what the land is to be used for. To some extent this is common sense, as most people can appreciate that a small child playing in a residential garden is a far more sensitive land use than an adult working in an office with limited landscaping.
For each broad category of land use and for over a hundred chemicals that are commonly tested for, government organisations and industry bodies have published what are called Generic Assessment Criteria (GAC). In simple terms, if the concentration is above the appropriate GAC then the soil may present a risk to human health. In reality, the assessment is not as simple as a straightforward comparison of numbers with consideration of soil type, test method, statistical analysis, and professional judgement based on experience all required.
If a result does pose a potential risk to human health, it may be appropriate to undertake a more detailed site-specific quantitative risk assessment or further testing. All contaminated land assessment is a tiered approach so that at each step only the real issues of concern are focused upon.
It not just the soil that needs to be assessed. Protecting the quality of groundwater and surface water is of vital importance so these too are routinely tested and the results assessed.
Hazardous ground gases, sometimes called landfill gases, can be released from both natural sources and contaminated land. Whilst these gases are naturally present in soils, when concentrations reach certain percentages they can be toxic or even explosive.
Whatever the numbers are, BRD can advise not only what they mean, but more importantly what needs to be done.
