Margarita Gutierrez-Ruiz

Abstract:

The Mexican environmental standard for the remediation of polluted soil (NOM-147) contains an option to determine the remediation objectives based on human health risk assessment, using as a correction factor the bioavailability in vitro (bioaccessibility) [1, 2], in the gastric phase. Some studies in animals show that to determine bioaccessibility, it is better to take into consideration the gastric and intestinal phases [2].<br /> <br />To expedite the measurements of bioaccessibility a simple and low-cost equipment was developed which allows pH control and the addition of reagents without interrupting the process. This simplifies the measurement in the gastric and intestinal phases based on physiological extraction method (PBET) [3]. The new equipment was evaluated by measuring the bioavailability and bioaccessibility of As and Pb on standard reference soil (NIST Montana 2710). The results were compared with those reported by 14 laboratories [4]. The bioaccessibilties of Pb and As, considering only the gastric phase, were they like the results obtained "in vivo". The results including both phases were out of the "in vivo" range but were similar to the international results. We recommended the substitution of the equipment required by the NOM-147 [5] with the new extraction equipment designed to improve the procedure.