Application of Electrocoagulation and Electrolysis on the Precipitation of Heavy Metals and Particulate Solids in Washwater from the Soil Washing

Soil washing, ex situ mechanical technique, is one of the few permanent treatment alternatives to remove metal contaminants from soils by employing physical separation based on mineral processing technologies to remove discrete particles or metal-bearing particles and/or chemical extraction based on leaching or dissolving process to extract the metals from the soils into an aqueous solution. However, washwater remained from soil washing process contains discrete particulate particles along with heavy metals as solution phase to be treated separately, as well as this process can produce large amount of sludge that requires further treatment, slow metal precipitation, poor settling, the aggregation of metal precipitates. Electrical treatments including electrocoagulation and electrolysis can be effective in removing these substances from washwater. This paper reviews the theoretical models in applying electrocoagulation and electrolysis to remove heavy metals and discrete particulate particles in washwater by examining and comparing the status of washwater treatment technologies which have been undertaken, mostly in the US and EU for the period 1990-2012.

Quantitative differentiation of phenolic compounds in different varieties of buckwheat cultivars from China, Japan and Korea

The aim of this study was to determine the variation of phenolic compounds in common and tartary buckwheats collected from China, Japan and Korea. Two buckwheat varieties of each country were cultivated using nutrient solution and vermiculite in the greenhouse from February to May, 2012 and harvested at two-week intervals. Phenolics such as chlorogenic acid, C-glycosylflavones (orientin, isoorientin, vitexin, and isovitexin), rutin, and quercetin were quantified using high performance liquid chroma-tography (HPLC). At 17, 29, 44, 58, and 72 days after sowing (DAS), before harvesting each organs, rutin content of cultivars from China and Korea at 17 DAS was the highest (mean 43.63 and 39.95 mg?g–1 DW, respectively) than that of 29 and 44 DAS. However, two varieties from Japan at 44 DAS were documented maximum;whereas, the amount of rutin in “Hokkai T10” harvested at 44 DAS (58.36 mg?g–1 DW) was the highest of all cultivars. Rutin level in the leaves and stems at 72 DAS were comparatively higher than at 58 DAS. The highest of rutin content was found at 72 DAS (73.33 mg?g–1 DW) in “Hokkai T10” leaves followed by “Daegwan No.3-3” (61.13 mg?g–1 DW), “rice tartary” (53.89 mg?g–1 DW). Rutin content of flowers was presented as the highest amount in “Hokkai T10” at 72 DAS (88.3 mg?g–1 DW) was approximately 14-fold higher than that of 58 DAS (6.44 mg?g–1 DW). However, rutin content of flower in “Xiqiao No.2” was 3-fold higher at 72 DAS than at 58 DAS. Rutin and total phenolic compounds content in flowers, leaves, and stems were higher in the order. The content of four C-glycosylflavones in common buckwheat was higher than those in tartary buckwheat, but rutin content which accounted >90% of the total phenolic compounds was higher in tartary buckwheat. The highest amounts of chlorogenic acid and quercetin were measured in the flower of “Xiqiao No.2” (6.85 and 11.69 mg?g–1 DW, respectively). Based on these results, the presence of different phenolic compounds in all the varieties of buckwheat confirmed that it can be regarded as a potent source of functional foods.

Cultivation characteristics and flavonoid contents of wormwood (Artemisia montana Pamp.)

The aim of this study was to establish the optimum harvesting time and the content of flavonoids in the leaves, stems, and roots of Artemisia montana Pamp. A. montana was monitored from June to October in 2012. The yield of A. montana at high density (30 × 10 cm) was higher than that of A. montana at low density (30 × 20 and 30 cm). Yield in terms of dry weight was increased with an extended growth period and development stage. High yield achieved at 2580 and 2757 kg?10 a?1 in September and October, respectively. Among the leaves, stems, and underground plant organs, jaceosidin and eupatilin were mainly detected in the leaves, and the highest levels were observed in June, at values of 66.6 and 158.2 mg?100 g?1, respectively. In contrast, apigenin was the major compound detected in the underground plant organs, with levels ranging from 21.2 to 29.5 mg?100 g?1 until September. Therefore, optimal harvest times were between September and October, generating a high yield and adding economic value although a higher level of total flavonoids was observed in crops harvested in June.

Residue patterns of buprofezin and teflubenzuron in treated peaches

The biological half-life and final residue levels of buprofezin and teflubenzuron were examined in peaches over a 14-day cultivation period. The residue levels of buprofezin and teflubenzuron were analyzed by chromatographic method with recovery ranging from 84.0% to 96.6%. The biological half-lives of buprofezin andteflubenzuron were 4.88 and 11.49 days at the standard dose, and 4.40 and 10.86 days at a triple dose, respectively. The initial concentration of buprofezin exceeded the maximum residue limit (MRL) set in Korea, but the concentration decreased to below the MRL within 6 days after application. The initial and persisting concentrations of teflubenzuron were all below the prescribed MRL. The final residue levels of buprofezin and teflubenzuron were 0.17 and 0.10?mg·kg﹣1 following a standard single dose, and 0.20 and 0.23 mg·kg﹣1 following a triple dose, respectively. The final re-sidue levels of buprofezin and teflubenzuron were also compared with the good agricultural practices standards of the United States and Italy.

Residue patterns of indoxacarb and pyridalyl in treated cauliflower

The biological half-life and final residue levels of indoxacarb and pyridalyl were determined in cauliflower over a 10-day cultivation period following applications of a standard (100 g a.i.ha–1 and 200 g a.i.·ha–1, respectively) and double dose (200 g a.i.·ha–1 and 400 g a.i.·ha–1, respectively). The residue levels were analyzed by gas chromatography with recovery ranging from 92.1% to 109.7%. The biological half-lives of indoxacarb and pyridalyl were 6.33 and 7.74 days for the standard dose, and 6.26 and 7.44 days for the double dose, respectively. The initial and persisting concentrations of indoxacarb and pyridalyl were all below the Korean maximum residue limits for broccoli of 1.0 mgkg–1 and 3.0 mgkg–1, respectively.

Isolation and identification of alkaloids and anthocyanins from flower and bulb of Lycoris radiata using HPLC and LC-ESI-MS

Three anthocyanins (cyanidin 3-diglucoside, cyanidin 3-sambubioside and cyanidin 3-glucoside) together with eleven known alkaloids (lycoricidine, hipppeastrine,O-Demethyllycoramin, lycoricidinol, galanthine, lycorine, lycorenine, lycoramine, galanthamine, homolycorine and pretazettine) were identified in the flower and bulb of Lycoris radiata using high-performance liquid chromatography coupled with UV detection and electrospray ionization mass spectrometry. Anthocyanins play a major role in protecting plant’s DNA from the UV spectrum of sunlight and also in attracting insects for the purpose of pollination. Thus, knowledge on the contents and types of anthocyanins of L. radiata will help to evaluate the adaptive evolution of flowers and provide useful information for the ornamental breeding.

Heavy Metals in Brown Rice(Oryza sativa L.) and Soil After Long-Term Irrigation of Wastewater Discharged from Domestic Sewage Treatment Plants

A pot experiment was conducted in a plastic film house to evaluate the translocation and uptake of heavy metals(Pb,Cd,Cu,and Zn) into brown rice(Oryza sativa L.) and the heavy metals residues in soils which had previously been irrigated with domestic wastewater for a long time(3 years).The range of Pb,Cd,Cu,and Zn was 5.10 ± 0.01,0.105 ± 0.017,5.76 ± 0.42,and 23.56 ± 1.40 mg kg-1,respectively in the domestic wastewater-irrigated soil,and 0.370 ± 0.006,0.011 ± 0.001,0.340 ± 0.04,and 2.05 ± 0.18 mg kg-1,respectively,in the domestic wastewater-irrigated brown rice.The results indicated that application of domestic wastewater to arable land slightly increased the levels of Pb,Cd,Cu,and Zn in soil and brown rice(P < 0.01).The concentrations of heavy metals in brown rice were lower than the recommended tolerable levels proposed by the Joint FAO/WHO Expert Committee on Food Additives.However,the continuous monitoring and pollution control of hazardous materials from domestic wastewater are needed in order to prevent excessive build-up of heavy metals in the food chain.