Analyses of soil cadmium and copper contents on a Domérien soil series of Burgundy in France

AgroParisTech, Laboratoire de Chimie Analytique, 16, rue Claude Bernard, 75231 Paris, cedex 05, France. Institut National de la Recherche Agronomique(INRA), Unité de Science du Sol, Centre de Recherches d’Orléans, F45160, Ardon, France. Institut National de la Recherche Agronomique(INRA), Unité d’Agronomie, Centre de Recherches de Bordeaux, BP 81, F-33883, Villenave d’Ornon, cedex, France. Department of Companion Animal and Animal Resources Science, Joongbu University, 201 Daehangno, Chubu-myeon, Kumsan-gun, ChungcheongNam-do 312-702, Republic of Korea.

Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License (Prodanovic et al., 2012).As a result, Cd lowered the leaf contents of the photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) in common bean (Phaseolus vulgaris L. cv.Nebraska) plants (Aldoobie and Beltagi, 2013), and Cd stress enhanced antioxidant enzymes, guaiacol pero-xidase, glutathione reductase, ascorbate peroxidase and polyphenol oxidase in concentration and time dependent manner in leaves of hyacinth bean (Lablab purpureus) (D 'Souza and Devaraj, 2013).The Cd concentrations determined by EDXRF (high-sensitivity energy-dispersive X-ray fluorescence spectrometry) for ten samples of rice containing Cd at concentrations ranging from 0.05 to 2.42 mg/kg agreed with the values determined by atomic absorption spectrometry (Honma et al., 2013).
A field study was undertaken in five soil series (Domérien, Carixien, Terres noires, Sols marron, Aubes) from the southern part of the Yonne district, Burgundy, France (Mench et al., 1997).This area has various soil series with either low or high geochemical Cd content in the topsoil.The wheat Cd content on 5 soil series were reported as follows (Mench et al., 1997); (Domérien < Carixien < Terres noires < Sols marron < Aubes).After the work of Mench et al. (1997), we took the work of knowing the relations between extracting time and extracted Cd and Cu contents from the two soils in the Domérien soil series.The absorbance of the two mineral elements was determined by atomic absorption spectrophotometry (Arnaud, 1998;Park et al., 2008) and pH was determined.The aim of this study was to determine the availability of Cd (Etherington, 1982;Alloway, 1990) thus, some results analysing soil Cd and Cu contents on Domérien region of Burgundy (Bourgogne) in France are hereby presented.

MATERIALS AND METHODS
Soil samples were collected on 0.3 m 2 area with a spade from the 0 to 0.25 m surface-ploughed layer in fields at 2 sites on Domérien region from the Yonne district of Burgundy, France (Mench et al., 1997).Soil samples were air-dried, 2 mm sieved and re-homogenized.And the soil samples from the Domérien soil series were used for the analyses of Cd and Cu contents.The names of these soils are Dubloc and Bierry.
The method for extraction was giving by Lebourg (1996) and Ghestem (1997).The time for extraction was from 5, 10, 20, 30, 60, 300, up to 1 440 min (24 h) for the two soils.And the reagent for extraction was 0.05 M EDTA (ethylene diamine tetraacetic acid) on the form of Na 2 H 2 EDTA and the soil was extracted by an agitator into a polyethylene bottle (volume around 50 ml) and the extracted solution was filtrated with a Millipore system (radius of membrane,  = 0.45 m).The weight of soil and the amount of EDTA were 10 g and 30 ml, respectively.The experiment was carried out on Laboratoire de Chimie Analytique of Institut National Agronomique Paris-Grignon(INA P-G) in France from February 10, 1998 to January 20, 1999.The Cd and Cu contents of the extracted soil solution were determined by air-acetylene flame atomic absorption spectrophotometer (AAS) (model: VARIAN SPECTRAA 250 PLUS), and their wave lengths were 228.8 m and 324.8 m, respectively.A background correction mode was used for Cd analysis (Park et al., 2008), but was not used for Cu analysis (Pinta et al., 1979).

RESULTS AND DISCUSSION
Table 1 shows the absorbance, cadmium (Cd) content and pH values of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil, and Table 2 shows these values on Bierry soil on the Domérien soil series on a background correction mode.The two soils were acidic, and the data of absorbance value was different between Tables 1 and 2. It is natural because the condition of each analysis was different.The quantity of the extracted Cd increased with the advance of extracting time (5-1440 min), and around 70% of Cd contents were extracted on 20 min of extraction.There were several factors responsible for the decision of Cd content with an atomic absorption spectrometer, for example, pH, concentration of EDTA, duration of extraction or ratio of weight/volume of solution (Ghestem, 1997).
Table 3 shows the absorbance, Cu content and pH values of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil, and Table 4 shows these values on Bierry soil on the Domérien soil series not on a background correction mode.Table 3 and Table 4 show the variance of the absorbance and the extracta-ble Cu content on the 2 French soils with an atomic absorption spectrometer.The absorbance value was different from that of Kim et al. (2000), and the data bet-ween Table 3 and Table 4 was also different.Pinta et al. (1979) wrote that there are some factors which have effect on the changes of absorbance of Cu, for example, temperature, associated anion and interaction with other minerals.The quantity of the extracted Cu increased with the advance of extraction, and around 65% of Cu contents were extracted on 30 min of extraction.
Table 5 shows the comparison of soil Cd values on the Domérien soil series with the data of Mench et al. (1997).The total Cd, which has been obtained on humid digestion (mineralisation) with utilising HNO 3 , HCl and HF (Mench et al., 1997), was 0.14 (mg Cd/ kg soil) on Dubloc soil and 0.22 (mg Cd/ kg soil) on Bierry soil, respectively.And on Table 5, there was a significant difference in Cd content between those on a background correction mode and those not on a background correction mode.As written previously it is natural, because the condition of each analysis differs.There was no significant difference bet-ween total Cd (Mench et al., 1997) and Cd extractable on our present results (68-107% of total Cd).
Table 6 shows the comparison of soil Cu values on the Domérien soil series with the data of Mench et al. (1997).The total Cu, which has been obtained on humid digestion (mineralisation) by utilising HNO 3 , HCl and HF (Mench et al., 1997), was 10.4 mg Cu/ kg soil on Dubloc and 15.7 mg Cu/ kg soil on Bierry, respectively.There were big differences between total Cu (Mench et al,   *, 10 g soil +30 ml EDTA, and the samples were agitated and filtrated on 2-3 November 1998; **, the number, 1, was used instead of 0 in order to calculate the natural logarithm value of 0 ; ***, Analysed with an atomic absorption spectrophotometer not on a background correction mode. 1997) and those of our present results (20-28% of total Cu).But the range of this decrease was not as large as that of Cd contents as shown in Table 5. Ghestem (1997) utilized an acidic pH and a neutral pH conditions, and the 1) The total Cd, which has been obtained on humid digestion (mineralisation) with utilising HNO 3 , HCl and HF (Mench et al, 1997), was 0.14 (mg Cd/ kg soil) on Dubloc soil and 0.22 (mg Cd/ kg soil) on Bierry soil, respectively.
2) 10 g soil and 30 ml EDTA of 0.05 mol, it was extracted and filtrated on 19-20 october 1998.The value was obtained with an atomic absorption spectrophotometer not on a background correction mode, and the duration of extraction, it took 14 minutes and 34 minutes for Dubloc and Bierry soil, respectively; 3) The same method with that of 2), but the sampels were measured with an atomic absorption spectrophotometer on a background correction mode; 4) Extraction of Dubloc soil shown on   Cd content in the edible parts of vegetable species decreased with the increase of soil pH (Togami et al., 2011).In our work, Figure 3 shows the Cd content and pH value of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil on the Domérien soil series.These data were taken from Table 1.The Cd contents on 20 min (4th) and 30 min extraction (5th) were stable.And Figure 4 shows the Cu content and pH value of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil on the Domérien soil series.These data were taken from Table 3.Here, the Cu con-tents on 5 min (2nd) and 10 min (3rd), 20 min (4th) and 30 min extraction (5th) were stable.Figure 1 shows the absorbances of Cd and of Cu on Dubloc (Domerien) soil with an atomic absorption spectrophotometer, and Figure 2 shows the absorbances of Cd and of Cu on Bierry (Domerien) soil with an atomic absorption spectrophoto-meter.

Conclusion
The Cd content increased on higher pH range when     2 and Table 4).
varied in the present experiment.The Cu content showed same tendency with Cd, while the (Cu extractable/Cu total) ratio was significantly lower value of 20-28% than that value of the Cd ratio (Cd extractable/Cd total) of 68-107%.The Cd content was blocked in the middle of extracting time, while the Cu content kept continuing increasing upto the end of the extracting time.Therefore, the soil Cd could have a stronger effect on grain Cd content than those of Cu content.

Figure 1 .
Figure 1.Absorbances of Cd and of Cu on Dubloc (Domerien) soil with an atomic absorption spectrophotometer.

Figure 2 .
Figure 2. Absorbances of Cd and of Cu on Bierry (Domerien) soil with an atomic absorption spectrophotometer.

Figure 3 .
Figure 3. Cadmium(Cd) content and pH value of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil on the Domérien soil series (These data were taken from Table1).

Figure 4 .Figure 5 .
Figure 4. Copper(Cu) content and pH value of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil on the Domérien soil series (These data were taken from Table3)

Table 1 .
Absorbance, cadmium(Cd)content and pH values of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil on the Domérien soil series.
*, 10 g soil + 30ml EDTA, and the samples were agitated and filtrated on 17-18 december 1998; **, the number, 1, was used instead of 0 in order to calculate the natural logarithm value of 0; ***, Analysed with an atomic absorption spectrophotometer on a background correction mode; ****, the value of pH by EDTA (0.05 M).

Table 2 .
Absorbance, cadmium (Cd)content and pH values of extracted soil solution on natural logarithm value of the extracting time on Bierry soil on the Domérien soil series.
*, 10 g soil + 30 ml EDTA, and the samples were agitated and filtrated on 2-3 november 1998 ; **, the number, 1, was used instead of 0 in order to calculate the natural logarithm value of 0; ***, Analysed with an atomic absorption spectrophotometer on a background correction mode.

Table 3 .
Absorbance, copper(Cu)content and pH values of extracted soil solution on natural logarithm value of the extracting time on Dubloc soil on the Domérien soil series.
*, 10 g soil+30ml EDTA, and the samples were agitated and filtrated on 17-18 December 1998; **, the number, 1, was used instead of 0 in order to calculate the natural logarithm value of 0 ; ***, Analysed with an atomic absorption spectrophotometer not on a background correction mode; ****, the value of pH by EDTA (0.05 M).

Table 4 .
Absorbance, copper(Cu)content and pH values of extracted soil solution on natural logarithm value of the extracting time on Bierry soil on the Domérien soil series.

Table 6 .
(Mench et al, 1997)copper(Cu) values on the Domérien soil series with the data ofMench et al.(1997)(mg Cu/ kg soil).The total Cu, which has been obtained on humid digestion (mineralisation) with utilising HNO 3 , HCl and HF(Mench et al, 1997), was 10.4 (mg Cu/ kg soil) on Dubloc and 15.7 (mg Cu/ kg soil) on Bierry, respectively.2) 10 g soil and 30 ml EDTA of 0.05 mol, it was extracted and filtrated on the period of 19-20 october 1998.The value was obtained with an atomic absorption spectrophotometer without background correction, and the duration of extraction, it took 14 and 34 min for Dubloc and Bierry soil, respectively, 3) Extraction of Dubloc soil shown on Table3(17-18 december 1998) and of Bierry soil on Table4(2-3 november 1998) during 1440 min, and it was analysed on not background correction mode; *, One sample; **, One sample with 8 repeats.