Remediation of Benzo[a]pyrene and Chrysene-Contaminated Soil with Industrial Hemp (Cannabis sativa)

Abstract

The phytoremediation, with industrial hemp (Cannabis sativa), of a Hawaiian silty clay soil contaminated with two polycyclic aromatic hydrocarbons (PAHs), chrysene and benzo[a]pyrene, was studied. Hemp showed a very high tolerance to the contaminants. The growth rates of hemp, compared with control, in soils fortified with chrysene and benzo[a]pyrene at concentrations of each varying from 25 to 200 micrograms/g were consistently above 100%. The plants grew from seed for 45 days in soil fortified with PAHs at concentrations of 25, 50, and 75 micrograms/g. Controls were pots with contaminated soil but no plant. PAHs levels were significantly reduced in all pots (control and seeded pots), expect for one set at a high concentration of chrysene, which may be due to uneven spiking. A time course study over 28 days was done to monitor changes of microbial count and levels of chrysene. Little changes were observed for the total microbial count in the soil, and the concentration of chrysene in the soil decreased slightly in the pots containing plants. However, the chrysene levels in those pots were consistently lower than those in the pots without plants.

Specific hypomethylation of DNA is induced by heavy metals in white clover and industrial hemp

“…Since there is a lack of data about the relationship between heavy metal stress and methylation changes, the present study was focused on the effect of Cd, Ni and Cr on DNA methylation of two plant species: Trifolium repens L. and Cannabis sativa L. in order to determine a possible role of DNA methylation in genome defence and metal‐induced resistance. White clover was selected for its sensitivity to heavy metals, on the basis of previous researches (Yang et al 1995, Citterio et al 2002), whereas hemp is a good example of a metal‐tolerant plant, and is also used in phytoremediation studies (Campbell et al 2002, Citterio et al 2003).…”

Advances and the effects of industrial hemp for the cleanup of heavy metal pollution

“…3. 1摇 自然状态下工业大麻对不同重金属吸收能力 现有的研究表明,工业大麻主要通过植物化学合成和植物提取过程来实现对重金属的吸收 [39,73] ,其对 Pb、Zn、Cu、Ni、Cd 等有不同程度的吸收 [19,25,74] ,并且可以减少铜矿开采和加工地区的土壤 Cu、Zn、Cd 和 Pb 含 量 [39] 。 大麻对重金属 Cd、Cr 和 Ni 的富集能力和超富集植株相比低 100 倍,其超高的生物量对 Cd、Cr 和 Ni 吸收也是相当可观,甚至比同样面积的超富集植株还要多 [17] 。 此外,大麻还具有修复有机化合物( 多环芳烃、 蒽和苯并[ a] 芘) 污染土壤的能力 [23,75] [18] 。 然而 Sandra 等研究表明大麻对 Cd、Ni、Cr 的吸收能力为 Cd >Ni>Cr [17] 。 由此看出大麻对 Cd 和 Ni 的吸收能力,Linger 等人和 Sandra 等人的研究结论是相反的。 2009 年 Shi 等人对大麻的吸收能力做了更全面的研究,他们认为与其它能源作物相比,大麻对 Cd 的富集能力更 强 [76] ,而对 Cu、Zn 和 Ni 的吸收能力则表现为 Cu>Zn>Ni [23] ,对 As 和 Pb 的吸收量微不足道 [77] 的富集能力 [17] 。 3. 2摇 添加土壤改良剂状态下工业大麻对重金属的吸收能力 诸多研究表明,自然状态下植物修复效果不够理想 [24,78] 。 如不添加土壤改良剂,工业大麻等作物提取的 重金属量还是不够 [19,25] 。 有些重金属如 Pb,由于其与土壤固体形态形成很强烈的络合态,自然条件下 Pb 很 难从土壤中吸收出来 [25,79] 。 为进一步提高植物修复的效果,必须人工添加一些化学螯合剂等,从而使工业大 麻提取的重金属量增加。 目前土壤改良添加剂主要有 EDTA、EDDS、DTPA、CDTA、EGTA、柠檬酸和苹果酸,而常用的添加剂是 EDTA 和 EDDS。 虽然两种添加剂对 Zn 的刺激作用相同 [19] ,但它们对其他的重金属的作用和功效却不同。 相比较,添加 EDTA 比 EDDS 更能刺激 Pb 和 Cd 的活性 [19,80] ,但 Kos 等的研究结果却表明添加 EDDS 使大麻 吸收 Pb 比对照增加了至少 100 倍 [25] 。 虽然添加 EDDS 后无法使大麻吸收 Cd 的能力增加,但与水平渗透障 碍屏障结合使用,可更多更安全的去除 Pb 和 Cd [81] 。 而添加 EDDS 比 EDTA 更能刺激 Cu 和 Ni 的活性,并能 最大程度的刺激 Cu 的去除,估计工业大麻每年吸收 Cu 量达 0.…”

Bioremediation of petroleum‐impacted soils from investigation‐derived wastes

“…LNAPLs (mostly aviation fuel) mixed with groundwater were extracted from the subsurface at the spill site and then separated from the water. Compounds within the extracted aviation fuel were identified by Gas Chromatography-Mass Spectrometry, using previously reported instrumentation (Campbell et al, 2002).The ions were monitored in full scan mode, injector temperature was 250°C, the oven was held at 35°C for 2 minutes, then ramped at 10°/minute to 280°C and held there for five minutes.The chromatogram is shown in Exhibit 1 with labels on those peaks that could be identified.…”