Metals in Soil and American Chestnut Tissue in Experimental Soil Treatments Plots on a Coal Mine Reclaimed Site

Abstract

Abstract:The Appalachian Regional Reforestation Initiative outlines planting methods that include preparation of a deep-rooting zone for healthy tree establishment (> 1.3 m deep). Continued monitoring may show that soil-ripping has pronounced effects in later years. However, little is known about the interactions of reclamation methods, buried metals, and micronutrients in soils on reclaimed coal mined sites. This study examined soil samples and plant tissue in eight-year-old pure American (Castanea dentata) and hybrid chestnuts BC1F3, and BC2F3 (C. dentata × C. mollissima) on a reclaimed coal mine site located in Dresden, Ohio under various treatments: 1) untreated control plots, 2) plots plowed and disked to 30 cm depth, 3) plots deep-ripped to 1 m depth, and 4) a combination of ripped and plowed/disked. Soil samples were collected in triplicate from all four treatments (n=3). Leaves were collected from a randomly selected subset of 108 trees (n=9). Flowers were collected from this subset (22 individuals), representing all treatments. Soil, leaves, and floral tissue were analyzed for silver (Ag), aluminum (Al), arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb), selenium (Se), and zinc (Zn) using inductively coupled plasma-mass spectrometry. No differences were detected when metal concentrations in soil, foliage, and floral tissue were compared among soil preparation treatments and chestnut tree types. Soil concentrations of Cu, Mn, and Se were detected at higher levels than county averages. Differences were noted when metal concentrations in soil were compared to chestnut leaves and chestnut floral tissue (P < 0.05). Elements including As and Cd were detected in soils but not found in tree tissue, indicating no potential transfer into the food chain. However, Se and Cu concentrations in chestnut floral tissue were significantly higher when compared to foliage (P = 0.004 and < 0.0001), which merits monitoring focused on metal concentrations in developing chestnut seeds.