“…Wilson (1997) provides an extensive list of sample substrates and associated inhibitors. Trace amounts of humic substances, heavy metals, constituents of bacterial cells, proteolytic enzymes, and high concentrations of non-target DNA have all been associated with the inhibition of the PCR in environmental matrices such as air, soil, water, sewage, and sediment (Alvarez et al, 1994(Alvarez et al, , 1995Keswani, Kashon, & Chen, 2005;Maher, Dillon, Vermund, & Unnasch, 2001;Roe et al, 2001;Wilson, 1997).…”