Artifacts caused by collection of soil solution with passive capillary samplers

Soil solution was collected with passive capillary samplers (PCAPS) and zer o-tension samplers (ZTS) from A horizons of forested soils. The volume and chemistry of collected solutions were measured weekly during discrete seaso nal collection periods. Acid-washed PCAPS increased alkalinity (3-fold), pH (1-3 units), and concentrations of Ca (2-fold), Na (8-fold), and Si (4-fol d), relative to ZTS solutions. Aluminum concentrations were dramatically re duced in PCAPS compared with ZTS samples. Differences in solution chemistry were attributed to leaching and weathering of fiberglass wicking material utilized in the PCAPS. In addition, PCAPS collected greater volumes (normal ized by sampler area) of solution relative to ZTS in weak-structured sandy loam soil due to a preponderance of matrix now. The results indicate that t he PCAPS used in this study are not suitable for aqueous geochemical studie s of dilute soil solutions.