Soil lead (Pb) contamination is a recognized environmental and global health problem. Phytoextraction of Pb using switchgrass (Panicum virgatum L.), a second-generation biofuel crop, is typically enhanced by soil chelation. The effectiveness of four different chelating agents, phytic acid (inositol hexaphosphate), citric acid, NTA (nitrilotriacetic acid), and EDTA (ethylenediaminetetraacetic acid) was examined in pot culture. Plants treated with EDTA (1 mM) showed significantly higher shoot Pb concentrations compared to control plants and plants treated with other chelates. Lead-solubility following phytoextraction was examined by soil washing using 0.01 and 0.05 M acetic acid as an extractant solution revealed no significant differences in Pb concentrations in soil among different chelate treatments and control. Furthermore, the effects of different concentrations (1, 2, 5 and 10 mM) of NTA on Pb phytoextraction of switchgrass were examined. Plants receiving 5 mM and 10 mM NTA had significantly higher foliage concentrations of Pb compared to plants treated with lower levels (1 and 2 mM) of NTA. Moreover, the effect of NTA application alone was significantly improved by a combined application of Triton X-100, an alkyl polyglucoside (APG); the Pb concentration in the foliage of switchgrass was more than doubled when treated with NTA combined with APG. The use of NTA combined with APG has great potential in improving phytoextraction efficiencies of switchgrass on Pb-contaminated soils.

The accumulation of Pb deposits in soil is a growing global concern. Soil remediation options include phytoextraction that involves the use of plants and associated soil microorganism. Switchgrass ( Panicum virgatum L.), a second-generation bioenergy crop was used in this study due to its ability to produce high biomass and grow in metal polluted soils. Plants were grown in Pb-contaminated soil (5,802.5 mg kg −1 ) in an environmentally controlled greenhouse. Plants were treated with exogenous application of the plant growth regulator (PGR) benzylaminopurine (BAP) or complete foliar nutrient solution (Triple-12 ® ) twice a week until harvested. Plants also received the soil fungicide propiconazole (Infuse ™ ) that was followed by the soil chelate nitrilotriacetic acid (NTA). Two concentrations of NTA were compared (5 mM and 10 mM) and combined application of NTA (10 mM) + APG (alkyl polyglucoside). Soil fungicide (propiconazole) was used to arrest arbuscular mycorrhizal fungi (AMF) activities in the roots of switchgrass in order to enhance Pb-phytoextraction. Lead (Pb) was measured in dry plant materials using an ICP-OES. Phytoextraction by switchgrass was significantly improved by dual soil applications of 10 mM NTA, APG and foliar applications of BAP which resulted in the greatestaverage Pb concentration of 5,942 mg kg −1 . The average dry mass of plants and the average value for total phytoextracted Pb (mg) per pot were significantly greatestfor plants treated with 10 mM NTA, APG and BAP. Also, plants treated with NTA and BAP showed average bioconcentration factor of 1.02. The results suggested that chemically enhanced phytoextraction significantly improved biomass production of switchgrass and at the same time increased phytoextracted Pb which is important for phytoremediation and bioenergy industry.

Lead (Pb) soil contamination is widespread and poses a threat to human health. Even chronic exposure to low levels of Pb contaminated soils is potentially harmful to organisms. Remediation of Pb-contaminated soil can be accomplished through phytoextraction, a technique that uses plants and associated soil microorganisms. The North American native switchgrass (Panicum virgatum L.), a second-generation bioenergy crop was used in this study due to its ability to produce high biomass and grow on marginal lands. In this study the effects of exogenous foliar application of the plant growth regulators diethyl aminoethyl hexanoate (DA-6) and salicylic acid (SA) were examined separately but in conjunction with the soil-fungicide propiconazole and soil chelate nitrilotriacetic acid (NTA) in order to optimize phytoextraction of Pb. Plants were grown under controlled conditions using highly Pb-contaminated (5802.5 mg kg(-1)) soil derived from a superfund site. Foliar application of the plant growth regulator DA-6 resulted in significantly higher Pb concentrations in the foliage of plants compared to Control plants. The DA-6 did, however, not improve plants dry mass (DM). Foliar application of salicylic acid resulted in significantly greater DM of the foliage compared to Control plants. The DM of plants treated with foliar application of salicylic acid was 46% higher than those of Control plants. Foliar application of salicylic acid did not improve significantly Pb concentration of foliage compared to Control plants. The findings reported in this study will potentially improve phytoextraction by switchgrass grown in Pb contaminated soils.

Lead (Pb) soil contamination is widespread and poses a threat to human health. Even long-term exposure to low levels of Pb contaminated soils is potentially harmful to organisms. Soil remediation options include phytoextraction that has gained particular attention due to low cost and minimal soil disruption. The North American native switchgrass (Panicum virgatum L.), a second-generation bioenergy crop was used in this study due to its ability to produce high biomass and grow on marginal lands. In this study, the effects of supplementary soil nitrogen (N) or foliar iron (Fe) application on the growth and metal uptake of switchgrass were examined. Plants were grown under controlled conditions using Pb (5802.5 mg kg(-1)) contaminated soil. The soil nitrogen (N) application involved three levels: control (no added N), medium (500 mg kg(-1)), and high (1000 mg kg(-1)). Plants receiving the high N had the significantly greatest dry mass (DM) of the foliage and the highest Pb concentration. The iron (Fe) foliar application involved two levels: (1) deionized water and (2) iron (20 mg kg(-1)) solution. Plants were additionally treated with the soil fungicide propiconazole (2 mg L-1) and the soil chelate nitrilotriacetic acid (NTA) in order to enhance phytoextraction. Plants receiving the Fe foliar application had significantly higher DM of the foliage and significantly lower Pb concentrations in the roots and the foliage. These results will potentially improve phytoextraction by switchgrass grown in Pb contaminated soils.

Soil lead (Pb) contamination is a major environmental and public health risk. Switchgrass (Panicum virgatum), a second-generation biofuel crop, is potentially useful for the long-term phytoremediation and phytoextraction of Pb contaminated soils. We evaluated the efficacy of a coordinated foliar application of plant growth regulators and soil fungicide and a chelator in order to optimize phytoextraction. Plants were grown in soil culture under controlled conditions. First, three exogenous nitric oxide (NO) donors were evaluated at multiple concentrations: (1) S-nitroso-N-acetylpenicillamine (SNAP); (2) sodium nitroprusside (SNP); and (3) S-nitrosoglutathione (GSNO). Second, the effect of SNP (0.5 μM) was examined further with the model chelate EDTA and the soil fungicide propicanazole. Third, a combined foliar application of SNP and gibberellic acid (GA3) was examined with EDTA and propicanazole. The soil application of propiconazole (a broad-spectrum fungicides) reduced AMF colonization and allowed greater Pb phytoextraction. The foliar application of SNP resulted in similar concentrations of Pb (roots and foliage) to plants that were challenged with chelates and soil fungicides. The combined foliar application of SNP and GA3 resulted in significantly greater average Pb concentration (243 mg kg−1) in plant foliage in comparison to control plants (182 mg kg−1) and plants treated with GA3 alone (202 mg kg−1). The combined foliar application of SNP and GA3 resulted in the greatest phytoextraction efficiency and could therefore potentially improve phytoextraction by switchgrass grown in Pb contaminated soils.

Lead (Pb) contamination in soil represents a threat to human health. Phytoextraction has gained attention as a potential alternative to traditional remediation methods because of lower cost and minimal soil disruption. The North American native switchgrass (Panicum virgatum L.) was targeted due to its ability to produce high biomass and grow across a variety of ecozones. In this study switchgrass was chemically enhanced with applications of the soil-fungicide benomyl, chelates (EDTA and citric acid), and PGR to optimize phytoextraction of Pb and zinc (Zn) from contaminated urban soils in Atlanta, GA. Exogenous application of two plant hormones was compared in multiple concentrations to determine effects on switchgrass growth: indole-3-acetic acid (IAA), and Gibberellic Acid (GA3), and one PGR benzylaminopurine (BAP), The PGR BAP (1.0 μM) was found to generate a 48% increase in biomass compared to Control plants. Chemical application of citric acid, EDTA, benomyl, and BAP were tested separately and in combination in a pot experiment in an environmentally controlled greenhouse to determine the efficacy of phtyoextraction by switchgrass. Soil acidification by citric acid application resulted in highest level of aluminum (Al) and iron (Fe) in plants foliage resulting in severe phytotoxic effects. Total Pb phytoextraction was significantly highest in plants treated with combined chemical application of B + C and B + C + H. Suppression of AMF activities by benomyl application significantly increased concentrations of Al and Fe in roots. Application of benomyl reduced AMF colonization but was also shown to dramatically increase levels of septa fungi infection as compared to Control plants.

Analytical method transfer (AMT) and dissolution testing are important topics required in industry that should be taught in analytical chemistry courses. Undergraduate students in senior level analytical chemistry laboratory courses at Kennesaw State University (KSU) and St. John Fisher College (SJFC) participated in development, validation, and transfer of two dissolution testing methods for pharmaceuticals. These experiments were transferred between the two schools and underwent method equivalency testing by a different set of undergraduate students to validate the AMT. Student learning outcomes addressed at both SJFC and KSU include (1) significant learning gains across all 3 years of the study; (2) confidence in method development, writing standard operating procedures, and laboratory transfer of validated methods; (3) increased understanding of AMT and dissolution testing; (4) ability to operate dissolution testers, UV vis, and flame atomic absorption spectrophotometers; and (5) improved knowledge and understanding of figures of merit and statistical analysis.