Soil contamination by metals from anthropogenic activities （e.g., mining and smelting） is a major concern for the environment and human health. Environmental availability of cadmium （Cd）, lead （Pb）, zinc （Zn）,...Soil contamination by metals from anthropogenic activities （e.g., mining and smelting） is a major concern for the environment and human health. Environmental availability of cadmium （Cd）, lead （Pb）, zinc （Zn）, copper （Cu）, and indium （In） in 27 urban soils located around two former Pb and Zn smelters in Northern France were studied by analysing the chemical forms of these metals and evaluating their phytoavailability. These metals were determined using flame or electrothermal absorption atomic spectrometry （FAAS or ETAAS）, depending on their concentration levels. After optimisation of the ETAAS method, characteristic mass of In in water and aqua regia were 9.9 and 18 pg, respectively, showing the high sensitivity of the analytical procedure. Metal partitioning was conducted using a four-step sequential extraction procedure. The results showed that Cd and Zn were mainly in the acid-extractable and reducible forms in the urban soils studied. In contrast, Pb and In were largely in the reducible fraction. However, in some samples, the amount of In extracted in the residual or exchangeable fraction was higher than that in the reducible fraction. Copper was mainly found in the reducible and residual fractions. A pot experiment was conducted in a glasshouse with seven soils （six contaminated and one uncontaminated） and two plant species, ryegrass and lettuce. The results showed transfer of metals from the contaminated soils to the shoots of ryegrass and the edible part of lettuce. The metal bioconcentration factor was in the order of Cd 〉〉 Cu 〉 In 〉 Zn 〉〉 Pb for lettuce leaves, whereas for ryegrass shoots, three orders were found, Cd 〉 Zn 〉 Cu 〉〉 In 〉 Pb, Cd 〉〉 In 〉 Zn 〉 Cu 〉〉Pb, and Zn 〉 Cd 〉 Cu 〉 In 〉〉 Pb, depending on the physico-chemical properties of the soils, such as pH, cation exchange capacity, carbonates, and organic matter. It was established that the metal toxicity was related to the contamination levels and the physico-chemical properties, including pH, organic matter, and in a lesser extent, Ca, Mg, and phosphorus contents, of the soils. However, it was shown that lettuce could grow on soils having high Cd and CaCO3 contents. Cadmium was one of the most available metals while Pb was always the least available in the soils studied.展开更多
Cadmium(Cd)concentrations in the water extracts of ten contaminated soils by arsenic(As)with various iron(Fe)contents were measured using inductively coupled plasma atomic emission spectrometry(ICP-AES)and electrother...Cadmium(Cd)concentrations in the water extracts of ten contaminated soils by arsenic(As)with various iron(Fe)contents were measured using inductively coupled plasma atomic emission spectrometry(ICP-AES)and electrothermal atomic absorption spectrometry(ETAAS),Due to the potential spectral interferences of As and Fe in the quantification of Cd,two methods were used for the background compensation.The first method was based on the use of a deuterium lamp(BGCD2 mode).The second one required a Cd hollow cathode lamp pulsated with a current for which the intensity varies in the course of time(BGCSR mode).The results showed that the choices of the analytical technique and the method used for the background compensation depend on the Cd,As and Fe concentrations in the solution and the concentration ratios As/Cd or/and Fe/Cd.In comparison with the ICP-AES and the ETAAS in combination with the BGCD2 mode,it was shown that the high-speed self-reversal method(HSSR)was a more appropriate method to correct As and Fe spectral interferences during the Cd measurements.On the other hand,depending on the Cd concentration,it was established that no significant Fe interference occurred during the Cd determination even if Fe concentration was 50 mg/L,reflecting the efficiency of the HSSR method to overcome the Fe interferences in the determination of Cd concentration by ETAAS without any matrix modifier in water extracts.展开更多
文摘Soil contamination by metals from anthropogenic activities （e.g., mining and smelting） is a major concern for the environment and human health. Environmental availability of cadmium （Cd）, lead （Pb）, zinc （Zn）, copper （Cu）, and indium （In） in 27 urban soils located around two former Pb and Zn smelters in Northern France were studied by analysing the chemical forms of these metals and evaluating their phytoavailability. These metals were determined using flame or electrothermal absorption atomic spectrometry （FAAS or ETAAS）, depending on their concentration levels. After optimisation of the ETAAS method, characteristic mass of In in water and aqua regia were 9.9 and 18 pg, respectively, showing the high sensitivity of the analytical procedure. Metal partitioning was conducted using a four-step sequential extraction procedure. The results showed that Cd and Zn were mainly in the acid-extractable and reducible forms in the urban soils studied. In contrast, Pb and In were largely in the reducible fraction. However, in some samples, the amount of In extracted in the residual or exchangeable fraction was higher than that in the reducible fraction. Copper was mainly found in the reducible and residual fractions. A pot experiment was conducted in a glasshouse with seven soils （six contaminated and one uncontaminated） and two plant species, ryegrass and lettuce. The results showed transfer of metals from the contaminated soils to the shoots of ryegrass and the edible part of lettuce. The metal bioconcentration factor was in the order of Cd 〉〉 Cu 〉 In 〉 Zn 〉〉 Pb for lettuce leaves, whereas for ryegrass shoots, three orders were found, Cd 〉 Zn 〉 Cu 〉〉 In 〉 Pb, Cd 〉〉 In 〉 Zn 〉 Cu 〉〉Pb, and Zn 〉 Cd 〉 Cu 〉 In 〉〉 Pb, depending on the physico-chemical properties of the soils, such as pH, cation exchange capacity, carbonates, and organic matter. It was established that the metal toxicity was related to the contamination levels and the physico-chemical properties, including pH, organic matter, and in a lesser extent, Ca, Mg, and phosphorus contents, of the soils. However, it was shown that lettuce could grow on soils having high Cd and CaCO3 contents. Cadmium was one of the most available metals while Pb was always the least available in the soils studied.
文摘Cadmium(Cd)concentrations in the water extracts of ten contaminated soils by arsenic(As)with various iron(Fe)contents were measured using inductively coupled plasma atomic emission spectrometry(ICP-AES)and electrothermal atomic absorption spectrometry(ETAAS),Due to the potential spectral interferences of As and Fe in the quantification of Cd,two methods were used for the background compensation.The first method was based on the use of a deuterium lamp(BGCD2 mode).The second one required a Cd hollow cathode lamp pulsated with a current for which the intensity varies in the course of time(BGCSR mode).The results showed that the choices of the analytical technique and the method used for the background compensation depend on the Cd,As and Fe concentrations in the solution and the concentration ratios As/Cd or/and Fe/Cd.In comparison with the ICP-AES and the ETAAS in combination with the BGCD2 mode,it was shown that the high-speed self-reversal method(HSSR)was a more appropriate method to correct As and Fe spectral interferences during the Cd measurements.On the other hand,depending on the Cd concentration,it was established that no significant Fe interference occurred during the Cd determination even if Fe concentration was 50 mg/L,reflecting the efficiency of the HSSR method to overcome the Fe interferences in the determination of Cd concentration by ETAAS without any matrix modifier in water extracts.
