College of Resources and Environment, Yangtze University, Wuhan, China.
College of Resources and Environment, Yangtze University, Wuhan, China.
Chemosphere. 2019 Jul;227:462-469. doi: 10.1016/j.chemosphere.2019.04.083. Epub 2019 Apr 12.
Different light combinations can improve phytoremediation efficiency by increasing the biomass yield and metal concentrations of plants. However, there has been rare research of using hyperaccumulators to change metal fractions and its possible leaching risk during phytoremediation. It was investigated in this study the impacts of different intensities of blue and red light mixed on the biomass production and metal uptake of Noccaea caerulescens and the changes of water soluble and exchangeable metal fractions in soil. The biomass of N. caerulescens increased with light intensity. The increment was relatively slow at 50 m s, dramatically increased at 200 m s and decreased significantly when beyond. Under optimal light condition, N. caerulescens produced less biomass than Thlaspi arvense, but the former is significantly more efficient in phytoremediation than the latter because it can accumulate significantly more metals per unit biomass. Without light irradiation, N. caerulescens can deteriorate the potential leaching risk of Cu and Pb by increasing their water soluble and exchangeable fractions in soil comparing with T. arvense. The proportions of bioavailable fractions did not change under the treatment of light at an intensity of 50 m s, but decreased obviously when the intensity exceeded 100 m s. Therefore, using hyperaccumulator for multiple metal contaminated soil remediation should be conducted with caution since the species can mobilize all metals in soil but only hyperaccumulate part of them, and proper intensity of light can improve the phytoremediation effect and alleviate the leaching risk through decreasing bioactive metal fractions in soil.
不同的光照组合可以通过增加植物的生物量产量和金属浓度来提高植物修复效率。然而，利用超积累植物来改变植物修复过程中金属形态及其可能的淋溶风险的研究很少。本研究探讨了不同强度的红蓝光照组合对海州香薷生物量生产和金属吸收的影响，以及土壤中水溶性和可交换性金属形态的变化。海州香薷的生物量随光照强度的增加而增加。在 50 m/s 时，增量相对较慢，在 200 m/s 时急剧增加，超过时则显著减少。在最佳光照条件下，海州香薷的生物量低于野菘，但前者的植物修复效率明显高于后者，因为它可以在单位生物量内积累更多的金属。在没有光照的情况下，与野菘相比，海州香薷会增加土壤中铜和铅的水溶性和可交换性形态，从而增加其潜在的淋溶风险。在 50 m/s 的光照强度下，生物有效形态的比例没有变化，但当强度超过 100 m/s 时，比例明显下降。因此，在对多金属污染土壤进行修复时，应谨慎使用超积累植物，因为该物种可以使土壤中的所有金属都变得具有生物活性，但只能超积累部分金属，适当的光照强度可以通过减少土壤中具有生物活性的金属形态来提高植物修复效果并减轻淋溶风险。
