Identifying the potential sources of trace metals in water from subsidence area based on positive matrix factorization

Abstract

Water in the subsidence area is a good choice for solving the water shortage in the coal mining area of China. In this study, positive matrix factorization model has been applied for the concentrations of seven kinds of trace metals (Pb, V, Cr, Mn, Co, Ni and Cu) in water from the subsidence area in the Luling coal mine, northern Anhui Province, China for identifying and quantifying their potential sources. Statistical analyses (including coefficients of variation and P-value of Anderson–Darling test) of metal concentrations indicate that multi factors (geological weathering/dissolution, filling of coal gauge and anthropogenic discharge) are responsible for the metal concentrations in the water. Based on the variations of Q values, three sources have been determined by US EPA (US Environmental Protection Agency) positive matrix factorization model: coal gauge filling, geological weathering or dissolution and waste discharge. The contribution degrees of these sources for all of the pools are different, and therefore, different strategies (e.g. clean the waste and the coal gauge around and in the pools) should be applied with different pools.