Deposition of Glomalin-Related Soil Protein and Sequestered Toxic Metals into Watersheds

Abstract

We hypothesized that glomalin-related soil proteins (GRSP) are eroded in sufficient quantities to influence metal loading into watersheds. We tested correlations among GRSP, Glomeromycota fungi, and metals (cadmium, iron, lead, and manganese) in proteins extracted from embankment soils at seven locations along an urban/coastal watershed. Immunoreactive (IRSP) and easily extractable (EE-IRSP) glomalin ranged from 0.007 to 2.9 mg g(-1) and from 0.006 to 0.63 mg g(-1) of soils, respectively. Glomalin-bound metals (microg mg(-1) protein) were Cd = 0.00-0.338; Fe = 0.5-227.7; Pb = 0.11-188.95; Mn = 2.23-784.42). Glomeromycota fungi were detected in 24% of all samples tested with PCR targeting the 18S and 28S ribosomal DNA extracted from soils. Specific assay for G. intraradices showed 3.08 x 10(7) copies g(-1) and 1.96 x 10(3) copies g(-1) of soil at two sites. Estimated annual glomalin loading into the watershed ranged from 5.48 x 10(2) to 7.22 x 10(4) kg of IRSP and from 2.57 x 102 to 2.86 x 10(4) kg of EE-IRSP; including 2.7 kg (Cd), 6.3 x 10(3) kg (Fe), 5.06 x 10(2) kg (Pb), and 1.80 x 10(3) kg (Mn). These data provide insights into the sources and ecological fate of a ubiquitous soil protein and its metals content.

Natural attenuation in a slag heap contaminated with cadmium: The role of plants and arbuscular mycorrhizal fungi

“…At Site 1, it was highly variable (with an average of 0.22 ± 0.22); while at Site 2, it was 0.54 ± 0.14 and at Site 3, it was 0.56 ± 0.24 mg of EEGS/g. These valued are in accordance to these reported by Chern et al [52], which ranged from 0.007 to 2.9 mg/g soil.…”

“…These authors reported that glomalin extracted from two polluted soils (containing between 0.03 and 0.20 mg Cd/g soil determined by DTPA-available Cd) bound between 0.020 and 0.080 mg Cd/g of glomalin. Higher values of metal sequestration were observed by Chern et al [52]. They reported between 0 and 0.34 mg Cd/g protein in sediments containing from 18 mg Cd/g sediment, when the permissible limits are between 8.9 and 9.3 mg Cd/L of sediment.…”

“…They reported between 0 and 0.34 mg Cd/g protein in sediments containing from 18 mg Cd/g sediment, when the permissible limits are between 8.9 and 9.3 mg Cd/L of sediment. Additionally, other metals such as Fe, Pb, Mn and Zn may be sequestered by glomalin [52,53].…”

Effect of arbuscular mycorrhizal fungi on growth of Gmelina arborea in arsenic-contaminated soil

“…The secreted biomolecules as a result of mycorrhizal symbiosis assist host plants in their growth and strengthen their immune system. Biomolecule produced by fungal hyphae such as glomalin helps host plants to reduce the level of toxicity in soil by converting it into organic form and making it more bioavailable (Sanon et al 2006;Chern et al 2007). …”

Removal of lead from aqueous solutions by a poly(acrylic acid)/bentonite nanocomposite

“…Elevated levels of Pb in surface waters may be originated from deposits of atmospheric dust, industrial wastewater, urban runoff, and mine tailings (Chern et al 2007). Removal of Pb from the polluted waters and wastewaters is, therefore, important in terms of protection of the public and environmental health.…”