There is a serious flaw in the proposed Regulations which must be addressed. The Q.P. is required to collect "representative samples" for analysis because the accuracy of the lab analyses is fundamental to the conclusions and recommendation made in the phase 2 report. However, there is no guidance or instruction given as to how to ensure a sample is representative and even a cursory examination of the current practices shows that in all cases where the site condition standard (SCS) for a solid contaminant is in the low ppm or ppb levels (e.g. metals, PAHs), the current sampling practices cannot possibly be representative for two reasons:
1. The amount of sample collected by the Q.P. (50 - 150 grams) is far too small to truly represent the many tons of soil surrounding the sample location.
2. Compounding the problem is the laboratory which only analyses 0.5-1.5 g (~1%) of the sample submitted by the Q.P.
Any lab result that exceeds the Site Condition Standard (SCS), no matter how slight, must be accepted as "real" and be dealt with before an RSC can be registered. If the allowable limit happens to be in the low-to-sub-ppm levels (and many are), the lab CANNOT produce a representative result if the contaminant levels are near the limit because the 1 gram sub-sample they actually analyse only contains a few thousand soil particles and the chances of this sub-sample containing ANY contaminant particles is virtually zero. In such cases the lab reports a "non-detect"and the site is declared "clean" but if it does manage to include a contaminant particle, the lab will report a level of several hundred ppm (1 particle in 2000 particles = 500 ppm) and the site needs a cleanup. In the case of small exceedances of the SCS, both of these results are wrong. The level of uncertainty in the current process of collecting and analysing field samples is enormous when the allowable levels are very low as is the case for many contaminants and it results in futile efforts to track and eliminate slight exceedances during site investigations and cleanups. The current practice is to keep your fingers crossed that the verification samples sent to the lab contain so few contaminant particles that the 1 gram lab sub-sample will never find them and the lab certificate shows the site as "clean" and the cleanup as complete.
The answer to this is either to collect and analyse much larger samples (which the labs cannot handle) or run many more samples through the lab (which the client cannot afford).
Submitted May 15, 2019 12:47 PM