Biotic contribution of Mn(Il) removal at Pinal Creek, Globe, Arizona

Abstract

It is hypothesized that biotic factors are playing a large role in the formation of manganese oxide deposits in Pinal Creek. To test this hypothesis, a series of batch experiments were run to characterize the key processes that could control biotic and abiotic processes. It was determined that biotic systems remove manganese by at least a magnitude faster than abiotic systems, 0.00161 hr-1 compared to 0.00043 hr-1. Increasing pH augmented the rate constant; 0.05080 hr-1 for pH 7.8 to 0.00157 hr-1 for pH 6.0. Initial Mn concentration influenced manganese removal with the net rate of re1noval described by Michaelis-Menton kinetics. Mn oxides on sediments also influenced increased rates. There are many factors that control the removal and oxidation of manganese from Pinal Creek. Understanding the key variables are important in promoting naturally remediating systems.