نتایج جستجو برای: acid extractable metal
تعداد نتایج: 932867 فیلتر نتایج به سال:
The soil potassium status and effect of soil physical and chemical properties on it were investigated using 109 surface soils (0-30cm) from four regions in Guilan province. Neutral molar ammonium acetate extractable K (K-NH4OAc), boiling molar nitric acid extractable K (K-HNO3) and water soluble K were determined. Results showed that CEC and clay were normally frequency distributed while distri...
Sewage sludge application on farmland as fertilizer is commonly practiced in many countries. Sewage sludge is rich in macro- and micro- nutrients. However, high concentration of heavy metals in sludge may cause pollution of soil, groundwater and human food chain because of uptake of toxic metals by crops. The objective of this study was to determine residual and cumulative effects of sewage slu...
Establishing a simple yet reliable compost stability test is essential for a better compost quality control and utilization efficiency. The objective of this study was to examine the relationship between extractable organic carbon (OC) and compost stability based on 18 compost samples from five composting facilities. The compost samples were extracted sequentially with water for 2 h [water(2h)]...
A case of arsenic contamination has recently been detected in the Lami coastal environment during the course of a heavy metal monitoring in Fiji’s coastal environment. Twenty two surficial sediment samples were sampled during the 20082009 period, extracted for arsenic and analysed using graphite furnace atomic absorption spectrometry. Two sites within the Lami estuary recorded the highest As le...
Gale (2, 3) initially described the existence in bacteria of a metabolism-dependent process achieving the accumulation of freely extractable amino acids. During the studies described here a number of additional reports have appeared citing examples of amino acid (4, 5), carbohydrate (6), and phosphate (7) accumulations in bacteria. The mechanism of these accumulations is unknown. Christensen et...
Coprecipitates of heavy metals with Fe oxides may form in contaminated soil, water, and sediment systems, particularly when oxidation-reduction processes are occurring. Once formed, coprecipitates with ferrihydrite could limit heavy metal mobility, solubility, toxicity, and bioavailability in geochemical systems. In this study, Cd, Cu, Pb, and Zn were coprecipitated with Fe by titration to pHs ...
Helicobacter pylori is implicated in causation of peptic ulcers and gastric cancer and plays a pivotal role in gastric pathophysiology. In the present study we evaluated the relative efficacy of sonicated and acid-extractable antigens in the serodiagnosis of H. pylori infection in peptic ulcer patients by ELISA. In the present study we evaluated the relative efficacy of sonicated and acid-extra...
Many regulatory frameworks for sediment quality assessment include consideration of contaminant bioavailability. However, the "snap-shots" of metal bioavailability provided by analyses of porewaters or acid-volatile sulfide-simultaneously extractable metal (AVS-SEM) relationships do not always contribute sufficient information. The use of inappropriate or inadequate information for assessing me...
Concepts and developments for a new field in ecotoxicology, referred to as "landscape ecotoxicology," were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessmen...
Previous work has shown that cacao nib cadmium (Cd) concentrations decrease during fermentation, but only when reaching sufficiently low pH. In this work, lab-scale experiments (5 kg units) with lactic and acetic acid amendments were ineffective at reducing the total Cd concentration. contrast, water-extractable fraction of concentration clearly increased pH was decreased. When single pod deriv...
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