Quantitative Analysis of Total Petroleum Hydrocarbons in Soils: Comparison between Reflectance Spectroscopy and Solvent Extraction by 3 Certified Laboratories

Table 4

Interlab repetition statistics for low, medium, and high TPH levels.

TPH level (calculated)	AVG delta	AVG deviation	Max delta	Max deviation
Low (400–600)	190	83%	373	199%
Medium (2500–6000)	2203	103%	4382	209%
High (9000–12000)	4564	90%	7247	178%