title: Lignite reduces the solubility and plant uptake of cadmium in pasturelands.
abstract: Repeated application of Cd-rich phosphate fertilizers can lead to the accumulation of this nonessential element in soil. This can result in increased plant uptake, with possible breaches of food or feed safety standards. We aimed to determine whether lignite (brown coal) can reduce Cd solubility and plant uptake in New Zealand pasture soils. In batch sorption experiments, we tested the capacity of lignite and lignite-soil mixtures to sorb Cd at various soil pH and Cd loadings. Over a pH range of 4-7, Cd sorption by lignite was 1-2 orders of magnitude greater than by a typic immature pallic soil containing 2% carbon. The addition of 5 wt % lignite to a range of soils revealed that lignite addition was most effective in reducing soluble Cd in soils with low pH. In a greenhouse experiment, we tested the effect of lignite on the accumulation of Cd and other elements by perennial ryegrass, Lolium perenne (L.). The addition of just 1 wt % lignite to the aforementioned soil reduced plant Cd uptake by 30%, without adversely affecting biomass or the uptake of essential nutrient elements including copper and zinc. This may be due to preferential binding of Cd to organic sulfur in lignite.
authors.affiliation: Department of Soil and Physical Sciences, Lincoln University, New Zealand.
authors.forename: Michael
authors.initials: M
authors.lastname: Simmler
authors.forename: Lisa
authors.initials: L
authors.lastname: Ciadamidaro
authors.forename: Rainer
authors.initials: R
authors.lastname: Schulin
authors.forename: Paula
authors.initials: P
authors.lastname: Madejón
authors.forename: René
authors.initials: R
authors.lastname: Reiser
authors.forename: Lynne
authors.initials: L
authors.lastname: Clucas
authors.forename: Paul
authors.initials: P
authors.lastname: Weber
authors.forename: Brett
authors.initials: B
authors.lastname: Robinson
mesh_terms: D002104:Cadmium / Q000378:metabolism*; D005308:Fertilizers; D008031:Lignin / Q000737:chemistry*; D010944:Plants / Q000378:metabolism*; D012995:Solubility
chemical_list: D005308:Fertilizers; D002104:Cadmium; D008031:Lignin