title: Assessing availability, phytotoxicity and bioaccumulation of lead to ryegrass and millet based on 0.1 mol/L ca(NO3)2 extraction.
abstract: This study was conducted to assess availability, phytotoxicity and bioaccumulation of lead (Pb) to ryegrass (Lolium perenne L.) and millet (Echinochloa crusgalli) based on the 0.1 mol/L Ca(NO3), extraction. Effect of soil properties on availability, phytotoxicity and bioaccumulation of Pb to the two plants was also evaluated. Five soils with pH values varying from 3.8 to 7.3, organic carbon (OC) contents from 0.7% to 2.4%, and clay contents from 11.6% to 35.6% were selected. Soils were spiked with Pb to achieve a range of concentrations: 250, 500, 1000, 3000 and 5000 mg/kg. Pb availability in the spiked soils was estimated by extracting soil with 0.1 mol/L Ca(NO3)2. The results indicate that plants yield decreased with decreasing soil pH and increased with increasing soil clay and OC content. Negative relationship between available Pb and the relative dry matter growth (RDMG) of the two plants were significantly related. Available Pb used to assess EC20 (20% effective concentration) and EC50 (50% effective concentration) of millet was 119 and 300 mg/kg, respectively. Available Pb used to assess EC20 and ECs, of ryegrass was 63 and 157 mg/kg, respectively. Bioaccumulation, expressed as bioconcentration factors of Pb, was inversely related to soil pH, soil OC and clay content. Strong relationships were found between available lead and uptake by the two plants (i was 0.92 and 0.95 respectively). In general, 0.1 mol/L Ca(NO3)2 available Pb may be used to assess the availability, phytotoxicity and bioaccumulation of lead to the two plants tested.
authors.affiliation: Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China. sijt@mail.tsinghua.edu.cn
authors.forename: Si
authors.initials: S
authors.lastname: Ji-Tao
authors.forename: Tian
authors.initials: T
authors.lastname: Bao-guo
authors.forename: Wang
authors.initials: W
authors.lastname: Hong-tao
authors.forename: Nicholas
authors.initials: N
authors.lastname: Basta
authors.forename: Jackie
authors.initials: J
authors.lastname: Schroder
authors.forename: Mark
authors.initials: M
authors.lastname: Casillas
mesh_terms: D017610:Calcium Compounds / Q000302:isolation & purification* / Q000378:metabolism; D018525:Germination; D007854:Lead / Q000493:pharmacokinetics* / Q000633:toxicity; D008129:Lolium / Q000187:drug effects / Q000378:metabolism*; D009566:Nitrates / Q000302:isolation & purification* / Q000378:metabolism; D008897:Panicum / Q000187:drug effects / Q000378:metabolism*; D011786:Quality Control
chemical_list: D017610:Calcium Compounds; D009566:Nitrates; D007854:Lead; C059948:calcium nitrate