Chromeazurol-S (CAS) is a dye used for the spectrophotometric determination of metals, mainly aluminum (Al), berillium (Be) and copper (Cu). CAS has been widely used for determining the penetration of copper containing preservatives like CCA (AWPA A3-96). Additional uses include: i) detection of utility pole decay (Esyln, 1979), ii) a chemical spot test for aluminum in wood (Kukachka and Miller, 1980) and fungal production of iron III-binding siderophores in agar (Srinivasan et al., 1993, 1994). The objective of this study was to determine the mechanism of color change from pink (negative) to blue (positive) following brown-rot decay (BRD) of Southern pine and white-rot decay (WRD) of maple blocks using soil-block tests. Changes in wood metals (ppm) were estimated by inductive coupled plasma spectroscopy (ICPS). Although preliminary results suggest that increased translocation of iron into the wood by siderophores during BRD potentiated the CAS color changes, simultaneous translocation of aluminum into the soil blocks by brown-rot fungi (BRF) clearly contributed cumulatively to the positive CAS tests at 12 weeks.

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