Chemical analysis by core drilling or trenching?

Hello! We are planning to construct a new building on an already existing plot. Today I was on site with an earthworks contractor to get a quote for the earthworks. During this conversation, he made the following statement: A chemical soil analysis (for classification of the pollutant class) *by core drilling* would be pointless and would not be accepted by any landfill, even if it were carried out by a certified engineering firm. However, the engineering firms would keep this quiet, which leads to another analysis needing to be performed later during excavation. In his opinion, an excavator trench is required, during which the soil expert is present. Only in this way can a valid and universally accepted report be created. I had already obtained quotes for conducting a soil survey from various firms in order to plan the costs for the excavated material in advance. These are based on core drilling. Another earthworks contractor does not seem to have a problem with that, and I myself have not yet found any contradictory information. So what is true about this statement? Note: This is initially only about the chemical analysis, not a geotechnical investigation – the general contractor will conduct that later themselves. Thanks & best regards Der W

A chemical soil analysis (for classification of the contamination class) *by core drilling* would be pointless and would not be accepted by any landfill, even if it were carried out by a certified engineering office.