Make sure that you coordinate with the environmental engineer before doing any excavation at a site that might have contaminated soil. This material will need special permit to be removed form the site and not every facility will accept it. Your environmental engineer will be the ultimate responsible person at this stage, taking measurement at every few buckets. A handheld portable device would be used and unless the contamination detected is higher than the allowable limit, this measuring would not delay any schedule. Only if you encounter an area that has more than the allowable treshold of contaminated soil, then that soil would have to be stockpiled separately and covered, until it is removed. Covering that soil is important because if it rains before it is removed the water will wash away the contaminated particles into the site.