Use of Sequential, Single and Kinetic Extractive Schemes to Assess Cadmium (Cd) and Lead (Pb) Availability in Vietnamese Urban Soils

Abstract

Modified BCR sequential extraction, single equilibrium-based EDTA extraction and kinetic fractionation were used for estimating the Pb and Cd availability in a series of soil samples from 3 sites located in urban areas of Hanoi (Vietnam). These schemes were compared to identify a simple, rapid and cheap protocol for routine estimation of Pb and Cd remobilizable fraction and the related potential risk. The comparison of these three approaches revealed their convergence in terms of mobility patterns observed for Pb and Cd. Cd was characterized by higher extractibality and mobility whatever the approach. Pb was distinguished of Cd by its high association to Fe-oxides, lower extractability, lower rate of desorption and then lower mobility. For this environmental scenario, EDTA single scheme at equilibrium could be suggested as the best suited and a simple protocol for determination of the labile pool of Cd and Pb. The pseudo-total concentrations of Pb and Cd are actually below the Vietnamese standard level, contrary to the results obtained by other authors for agricultural soils at other urban sites of Hanoi.

Environmental and Geochemical Characteristics of Heavy Metals in Soils Around the Former Mining Area of Zeïda (High Moulouya, Morocco)

“…Figure 6 showed the average extraction rate during desorption of the three tailings (S1 + S2 + S3) and soils (S8 + S14 + S17) which increased progressively until the end of the experiments with EDTA and H 2 O. Approximately 70% of Pb was removed from the tailings, such a value was in agreement with other work in the field, which frequently reported Pb extractions > 60% with EDTA (Labanowski et al, 2008;Manouchehri et al, 2014). Pb was a mobile metal bound to the exchangeable fraction (76%), clearly highlighting the consistency between sequential and kinetic extractions.…”

Speciation Variation and Bio-Activation of Soil Heavy Metals (Cd and Cr) in Rice-Rape Rotation Lands in Karst Regions

“…The per capita occupancy of cultivated land resources is far below the average level of the world. Since the 1950s, the production performance and utilization value of soil have been declining due to the rapid development of modern industrial and agricultural production, the large application of pesticides and chemical fertilizers, and the continuous invasion of atmospheric dust and sewage on farmland [3]. The degradation of farmland soil quality is a serious threat to food security.…”

Evaluation of Heavy Metals in Soil Using Modified BCR Sequential Extraction

“…However, it is widely accepted that the total metal concentration in the soil is not a relevant indicator for assessing the risk posed by the presence of heavy metals for environment and food chain. The ecological effects of heavy metals are related to the mobile fraction rather than the total concentration; though not all pollutants are mobile, most hazardous pollutants tend to be mobile [5]. Heavy metals exist in different forms due to their binding to different soil constituents.…”

“…To determine the different binding pools and to provide information on the potential mobility and availability of heavy metals. Modified community bureau of references (BCR) protocol has been developed, modified and generalized as an attempt to harmonize different methodologies of the sequential extraction processes [5]. This work is aimed at assessing the efficiency of modified BCR sequential extraction technique in partitioning of heavy metals in the soil.…”

“…Heavy metals exist in different forms due to their binding to different soil constituents. The determination of these different forms usually called speciation or fractionation gives more information on mobility, bioavailability, potential toxicity and consequently the related risks [5].…”