Spectrophotometric Analysis of Chromium (VI) Levels in Varying Arizona County Water Samples used to Determine which County Water Contains the Most Toxicity when Introduced to Yeast

Abstract

This study analyzed the Chromium (VI) levels present in three Arizona counties tap water, as represented by the major universities residing within them. Each sample was surveyed using spectrophotometry to determine the contaminant levels of Cr(VI) in the water. Introduction to the yeast strain BY4742 was observed to determine whether the contaminated water dampened culture growth. When compared to the Maximum Contaminant Level (MCL) of 0.1 mg/L set by the EPA, Maricopa County contained 14x the amount allowable at 1.4 mg/L. The samples collected for Coconino County and Pima County also displayed contaminant levels higher than the set MCL at 0.3 mg/L and 0.5 mg/L, respectively. Data collected on yeast growth illustrated that Maricopa County was also the most hindering on yeast growth at an average cell count of 97. However, the chosen yeast strain also demonstrated an apparent resistance to Cr(VI) with an average cell count of 120 cells in the Cr(VI) plate. Due to this strains survival in Cr(VI) contaminated water, our initial hypothesis was rejected. Possible generational studies can be done to observe the toxic effects higher levels of Cr(VI) in drinking water have with regard to organismal growth hindrance and accumulation of the element leading to carcinogenic properties. Additional analysis on what other contaminants lie within Arizona counties can be performed, as well.