Soil characteristics and heavy metal accumulation by native plants in a Mn mining area of Guangxi, South China.

Revegetation and ecological restoration of a Mn mineland are important concerns in southern China. To determine the major constraints for revegetation and select suitable plants for phytorestoration, pedological and botanical characteristics of a Mn mine in Guangxi, southern China were investigated. All the soils were characterized by low pH and low nitrogen and phosphorus levels except for the control soil, suggesting that soil acidity and poor nutrition were disadvantageous to plant growth. In general, the studied mine soils had normal organic matter (OM) and cation exchange capacity (CEC). However, OM (8.9 g/kg) and CEC (7.15 cmol/kg) were very low in the soils from tailing dumps. The sandy texture and nutrient deficiency made it difficult to establish vegetation on tailing dumps. Mn and Cd concentrations in all soils and Cr and Zn concentrations in three soils exceeded the pollution threshold. Soil Mn and Cd were above phytotoxic levels, indicating that they were considered to be the major constraints for phytorestoration. A botanical survey of the mineland showed that 13 plant species grew on the mineland without obvious toxicity symptoms. High Mn and Cd concentrations have been found in the aerial parts of Polygonum pubescens, Celosia argentea, Camellia oleifera, and Solanum nigrum, which would be interesting for soil phytoremediation. Miscanthus floridulus, Erigeron acer, Eleusina indica, and Kummerowia striata showed high resistance to the heavy metal and harsh condition of the soils. These species could be well suited to restore local degraded land in a phytostabilization strategy.

[Surgical treatment for degenerative lumbar scoliosis associated with spinal stenosis].

OBJECTIVE: To study surgical techniques for degenerative lumbar scoliosis associated with lumbar stenosis and evaluate their clinical significane. METHODS: Thirty-two patients with degenerative lumbar scoliosis associated with spinal stenosis were treated by techniques of posterior lumbar interbody fusion or posterolateral fusion and pedicle screws. There were 18 male and 14 female with 56.8 years old on the average (ranging from 49 to 75 years). There were no evident change of lumberlordosis in 15 cases, and lumber lordosis were obvious loss associated with lumbar subluxation in 17 cases. The correcting, the improvement of back and leg pain, complications and followed-up results were analyzed retrospectively. RESULTS: Thirty-two cases were followed-up for 6 to 39 months (the average time of 13 months). The average correction rate of scoliosis was 58.0% and the rate of pain relief was (80.2 +/- 5.8)%. There were two cases of dura sac laceration, two cases of nerve roots injury and a case of pseudoarthritis. During followed-up, correction rate and height of disc spaces were not lost. Shift of interbody cages were no displaced; all the internal fixation got well fusion and the rate of fusion for the bone graft was 96.9%. CONCLUSION: Posterior pedicle screws combined with interbody fusion or posterolateral fusion is a safe and effective surgical treatment for degenerative lumbar scoliosis associated with lumbar stenosis.