With industrialization, great amounts of trace elements and heavy metals have been excavated and released on the surface of the earth and dissipated into the environments. Rapid screening technology for detecting major and trace elements as well as heavy metals in variety of environmental samples is most desired. The objectives of this study were to determine the detection limits, accuracy, repeatability and efficiency of a X-ray fluorescence spectrometer (Niton XRF analyzer) in comparison with the traditional analytical methods, inductively coupled plasma optical emission spectrometer (ICP-OES) and inductively coupled plasma optical emission spectrometer (ICP-MS) in screening of major and trace elements of environmental samples including estuary soils and sediments, contaminated soils, and biological samples. XRF is a fast and non-destructive method in measuring the total concentration of multi--elements simultaneously. Contrary to ICP-OES and ICP-MS, XRF analyzer is characterized by the limited preparation required for solid samples, non-destructive analysis, increased total speed and high throughout, the decreased production of hazardous waste and the low running costs as well as multi-elemental determination and portability in the fields. The current comparative study demonstrates that XRF is a good rapid non-destructive method for contaminated soils, sediments and biological samples containing higher concentrations of major and trace elements. Unfortunately, XRF does not have sensitive detection limits of most major and trace elements as ICP-OES or ICP-MS but it may serve as a rapid screening tool for locating hot spots of uncontaminated field soils and sediments.

The objectives of this study were to investigate distribution and solubility of Pb, Cs and As in soils under electrokinetic field and examine the processes of coupled electrokinetic phytoremediation of polluted soils. The elevated bioavailability and bioaccumulation of Pb, As and Cs in paddy soil under an electrokinetic field (EKF) were studied. The results show that the EKF treatment is effective on lowering soil pH to around 1.5 near the anode which is beneficial for the dissolution of metal(loid)s, thus increasing their overall solubility. The acidification in the anode soil efficiently increased the water soluble (SOL) and exchangeable (EXC) Pb, As and Cs, implying enhanced solubility and elevated overall potential bioavailability in the anode region while lower solubility in the cathode areas. Bioaccumulations of Pb, As and Cs were largely determined by the nature of elements, loading levels and EKF treatment. The native Pb in soil usually is not bioavailable. However, EKF treatment tends to transfer Pb to the SOL and EXC fractions improving the phytoextraction efficiency. Similarly, EKF transferred more EXC As and Cs to the SOL fraction significantly increasing their bioaccumulation in plant roots and shoots. Pb and As were accumulated more in plant roots than in shoots while Cs was accumulated more in shoots due to its similarity of chemical properties to potassium. Indian mustard, spinach and cabbage are good accumulators for Cs. Translocation of Pb, As and Cs from plant roots to shoots were enhanced by EKF. However, this study indicated the overall low phytoextraction efficiency of these plants.

Cs is a common radionuclide present in nuclear wastes and released from nuclear power plant accidents. It is hard to be removed from water with traditional technology. The current study aimed at developing of efficient cost-effective adsorbent for removing Cs with modified MCM-41 with specific functional groups -SH. Mesoporous material MCM-41 was selected due to its large surface area and tunable pore structure. Functional -SH groups were grafted into the pores of MCM-41 to enhance its capability of selective adsorption of Cs from multi-element (Co, Sr) water solution. The adsorption results showed that the maximum adsorption capacity was 29.24 mg/g. Both Langmuir and Freundlich models described the adsorption processes of Cs, indicating co-existence of both monolayer and multilayer adsorption in the surface and inner pores of the materials. TEM, FTIR, and Raman spectroscopy analyses indicated that -SH groups were successfully bounded into the pores of MCM-41. The present study approved the surface functional modified MCM-41 which might be a good alternative candidate for cleaning up of radionuclide Cs from nuclear power plant accidents and relevant nuclear accident events.

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Phytoremediation is the use of living plants for the removal of contaminants from soil, water, sediments, and air. Soil contamination by heavy metals (HMs) is an important environmental concern. The success of phytoextraction, a subset of phytoremediation, as an environment clean-up technology depends on several factors including the extent of soil contamination and the bioavailability of the metal. The aim of phytoextraction research is to identify metal-tolerant plants that are capable of uptake and efficient translocation of HMs to harvestable above-ground organs. The main objective of this study was to assess the metal tolerance of coffeeweed (Sesbania exaltata Raf.) after exposure to lead (Pb) solutions. Sesbania plants were grown for 30 days at the Jackson State University greenhouse prior to exposure to different concentrations (0, 0.1, 1.0, 5.0, 10.0, 20.0 μM Pb) of lead nitrate. Four 30-day old seedlings were grown hydroponically in each designated 15-mL cup containing the Pb treatments. Plants were harvested after various exposure periods (0, 2, 5, 8, 12, 15 days). Morphological characteristics were evaluated, and lead contents were quantified by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Phytochelatin synthesis was determined indirectly by quantifying the acid-thiol contents of roots and shoots. Our results indicated that lead tissue uptake increased with increasing concentrations of lead (i.e. 20.0 μM versus 1.0 μM). However, plant roots and shoots displayed symptoms of toxicity as evidenced by their decreased biomass with increasing concentrations of lead. Also, plants exposed to higher Pb concentrations exhibited mild chlorosis. Overall, Sesbania was relatively tolerant to lead. Although acid-soluble thiol contents appeared to correlate with Pb uptake especially at higher concentrations of Pb treatments, phytochelatin synthesis as a metal-tolerance mechanism in Sesbania is inconclusive at this time. Further experiments are warranted to elucidate whether such tolerance mechanism exists in Sesbania.