Fractionation and speciation of arsenic in three tea gardens soil profiles and distribution of As in different parts of tea plant (Camellia sinensis L.)

Mobility and ecological risk assessment of trace metals in polluted estuarine sediments using a sequential extraction scheme

The three-stage sequential extraction procedure for the fractionation of Cd, Cr, Cu, Ni, Pb, and Zn, proposed by the Commission of the European Communities Bureau of Reference, was applied to sediment five samples collected from the Sal estuary, Sergipe State, northeast Brazil, in September 2009. The method showed satisfactory recoveries, detection limits, and standard deviations for determinations of trace metals in the sediments. Cd and Pb were the metals most prevalent in the bioavailable fractions (carbonates, Fe and Mn oxides, organic matter, and sulfides), while Ni, Zn, Cu, and Cr showed higher percentages in the inert fraction. The order of mobility of the metals was Cd (66%) > Pb (65%) > Zn (59%) > Ni (57%) = Cr (57%) > Cu (56%). Possible toxicity related to these metals was examined using the risk assessment code, and by comparing the chemical data with sediment quality guideline ERL-ERM values. Results obtained using the two methods were in agreement, and showed low to medium risk for all metals, indicating that adverse effects on aquatic biota should rarely occur.

Total and inorganic arsenic contents in some edible zingiberaceous rhizomes in Thailand

The arsenic accumulation in rhizomes of Zingiberaceous plants was determined by atomic absorption spectrometry interfaced with hydride generation system (HG-AAS). The raw herbal materials, rhizomes, were collected from different regions of Thailand between December 2011 and January 2012. Six well-known Zingiberaceous plants, 16 samples from each and a total of 96 samples, were analyzed Alpinia galanga (Khaa), Boesenbergia rotunda (Kra-chaai), Curcuma longa (Khamin-chan), Curcuma zedoaria (Khamin-oi), Zingiber cassumunar (Plai) and Zingiber officinale (Ginger). Concentrations of total arsenic based on dry weight were 92.4 ± 9.2, 103.5 ± 20.8, 61.7 ± 12.5, 89.8 ± 17.5, 106.7 ± 19.5 and 69.3 ± 11.8 ng/g, respectively and inorganic arsenic were 48.8 ± 7.0, 66.3 ± 12.7, 25.5 ± 5.0, 38.7 ± 4.7, 71.2 ± 11.6, and 38.5 ± 5.5 ng/g, respectively. Among these, Plai and Kra-chaai exhibited the highest levels of total arsenic and inorganic arsenic accumulation that remind consumers to be aware of excess consuming of these rhizomes. On the contrary, the lowest value found in Khamin-chan indicating natural dietary supplements and herbal medicines comprising Kamin-chan are safe from arsenic poison. All investigated amounts of total and inorganic arsenic were much lower than limits recommended by Thai Food and Drug Administration.

Distribution Pattern of Some Heavy Metals in the Soil of Silghat Region of Assam (India), Influenced by Jute Mill Solid Waste

Physico-chemical Analysis of the soil of Silghat region of Nagoan district of Assam, India was carried out to assess the possible effect of jute mill solid waste in the distribution pattern of some heavy metals. Soil samples were collected from ten different locations of the dumping site of the mill and their physico-chemical parameters were analyzed. Scanning Electron Microscopy-Energy Dispersive X-ray analysis (SEM-EDX) and Inductively coupled Plasma-Optical Emission Spectrometer (ICP-OES) analysis of the samples shows that soil of the dumping sites is highly enriched with heavy metals. The concentration of Fe, Cu, Zn and Pb in the contaminated soil was found to be very much higher than both the continental crust and world rock average values. Correlation studies indicate strong positive correlation between organic carbon content (Corg) with all the metals investigated. pH has negative correlation while positive correlation was observed for electrical conductivity with all the metals. Extent of metal contamination was assessed by determining contamination degree (CD) and pollution load index (PLI).