There were concerns about possible contamination of the site by hydrocarbons from the adjacent vehicle repair workshop.
In order to comply with the tight timescale we:
dug trial pits,
installed boreholes with gas monitors,
collected and tested contamination samples
and issued our report less than one week after receipt of instruction.
On a housing project located on an old industrial site the levels of arsenic in the soil were such as to give cause for concern.
Rather than remove the material from site, we undertook bio-accessibility testing in order to estimate the fraction of the contaminant soluble in the gastrointestinal tract, and therefore available for absorption into the blood stream. Using these test results we were able to demonstrate that there was no significant risk to human health posed by the soil which could therefore be left in place.
Removal of the soil with elevated arsenic to the required depth of approximately 500mm across the site would have cost an estimated £20,000. This compared with a site visit to collect some near surface samples, testing and report at a cost of around a tenth of this figure.
This proposed housing development site had been used as a plant yard and contained below ground fuel tanks which had been leaking for a considerable period.
It would have been possible to remove an assumed, say 500mm of soil from around the excavation left by removal of the tank and then take samples for testing at a laboratory to see if the contamination had been removed. If these showed continued presence of contamination then the operation would have to be repeated.
To avoid the expense of removing too great a quantity of potentially contaminated soil and the uncertainty and delay of removing insufficient contaminated material insitu testing was used. When the insitu results indicated that sufficient material had been removed samples were taken for confirmation in the laboratory.