Feng Jianting, Burke Ian T, Sepúlveda Olea Felipe E, Chen Xiaohui, Stewart Douglas I
School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK.
Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, 210024, Jiangsu, China.
Environ Geochem Health. 2025 Apr 13;47(5):172. doi: 10.1007/s10653-025-02482-0.
Risk management for agricultural use of digested sewage sludge requires better understanding of the behaviour and fate of contaminant metals in the plant root zone. A study employing rhizo-pot and plug-tray experiments was conducted to identify the zone near spring barley roots (Hordeum vulgare) where concentration and speciation of Cu and Zn are affected. Cu and Zn bonding environments in the root epidermis/cortex and vascular tissue were also identified. In the digested sludge-amended soil, spring barley absorbed Cu only from the immediate vicinity of the roots (<< 1 mm), but Zn was taken up from further afield (> 1 mm). In the rhizosphere Cu was predominately present as Cu(I) oxides or as Cu(II) absorbed/bonded to phosphate, whereas Zn was present as Zn(II) in inner-sphere complexes with metal oxide surfaces, as Zn(II) sulphides or Zn(II) bonded to/incorporated into carbonates. Cu taken-up by spring barley roots was largely sequestered in the root epidermis and/or cortex predominately in the coordination environments similar to those seen in the rhizosphere. Only a small proportion of the Cu was translocated into the vascular tissue (where it is in the same two bonding environments). Zn taken-up by spring barley roots was present as Zn(II) sulphides, Zn(II) absorbed to/incorporated into carbonates, or Zn(II)-organic complexes. Zn was readily translocated from roots to shoots. Better understanding of these differences in the mobility and uptake of Cu and Zn in sludge-amended agricultural soils could be used to undertake element specific risk assessments.
消化污泥农业利用的风险管理需要更好地了解植物根区中污染金属的行为和归宿。开展了一项采用根际盆栽和育苗盘实验的研究，以确定春大麦（Hordeum vulgare）根系附近铜和锌浓度及形态受到影响的区域。还确定了根表皮/皮层和维管组织中铜和锌的键合环境。在添加了消化污泥的土壤中，春大麦仅从根系紧邻区域（<<1毫米）吸收铜，但锌则从更远区域（>1毫米）吸收。在根际，铜主要以氧化亚铜形式存在，或作为与磷酸盐结合/吸附的铜（II）存在，而锌则以内层配合物形式与金属氧化物表面的锌（II）、硫化锌（II）或与碳酸盐结合/掺入碳酸盐中的锌（II）形式存在。春大麦根系吸收的铜主要螯合在根表皮和/或皮层中，其配位环境与根际中所见的相似。只有一小部分铜转运到维管组织中（其处于相同的两种键合环境）。春大麦根系吸收的锌以硫化锌（II）、吸附/掺入碳酸盐中的锌（II）或锌（II）有机配合物形式存在。锌很容易从根转运到地上部分。更好地了解污泥改良农业土壤中铜和锌迁移性及吸收的这些差异，可用于进行元素特异性风险评估。
