Food Additives & Contaminants
ISSN: 0265-203X (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/tfac19
Cadmium and lead distribution in fresh asparagus G. Zurera‐Cosano , R. Moreno‐Rojas & M. A. Amaro‐Lopez To cite this article: G. Zurera‐Cosano , R. Moreno‐Rojas & M. A. Amaro‐Lopez (1990) Cadmium and lead distribution in fresh asparagus, Food Additives & Contaminants, 7:3, 381-385, DOI: 10.1080/02652039009373903 To link to this article: http://dx.doi.org/10.1080/02652039009373903
Published online: 10 Jan 2009.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tfac20 Download by: [Universite Laval]
Date: 13 November 2015, At: 17:58
FOOD ADDITIVES AND CONTAMINANTS, 1990, VOL. 7, NO. 3, 381-385
Cadmium and lead distribution in fresh asparagus G. ZURERA-COSANO, R. MORENO-ROJAS and M. A. AMARO-LOPEZ Department of Food Hygiene and Technology, University of Cordoba, Medina Azahara, 9. 14005 Cordoba, Spain
Downloaded by [Universite Laval] at 17:58 13 November 2015
(Received 17 July 1989; revised 18 September 1989; accepted 29 September 1989) Cadmium and lead were determined in fresh asparagus, as a function of diameter and portions, by atomic absorption spectrophotometry to evaluate the contribution of these vegetables to the daily intake of cadmium and lead in Spain. Cadmium content of the asparagus ranged from less than 0·006 mg/kg to 0.062 mg/kg, whereas lead content varied from 0·059 to 0.409 mg/kg. The concentration of cadmium and lead was compared statistically for the different diameters and portions of asparagus. The asparagus tip/remainder ratio metal concentration was determined and a greater concentration of cadmium and lead in the tip relative to the remainder of the asparagus was observed. If we take into account the mean level of cadmium and lead (0.022 mg/kg and 0.165 mg/kg respectively), the daily intake contribution of these metals in Spain is 0.04 µg/day for cadmium and 0.3 µg/day for lead. Keywords: Cadmium, lead, heavy metals, asparagus
Introduction
Heavy metal contamination of agricultural land is widely recognized as a potential problem for human health. Cadmium and lead are toxic substances which accumulate in the body due to their low rate of elimination. Determination of traces of heavy metals in vegetables has assumed considerable importance in recent years (Lopez etal. 1986, Zurera et al. 1987), but little has been done to show the effect of the diameter and portion factors in the heavy metal content of asparagus. The purpose of this work was to determine and compare the concentration of lead and cadmium in fresh asparagus, and to determine if the distribution of these elements was a function of diameter and/or portion. At the same time the contribution of asparagus to the daily intake of cadmium and lead in Spain was evaluated. Material and methods
Samples Samples of asparagus were obtained from Egnolac, S.A., Palma del Rio (Spain) and processed in our pilot-plant. The asparagus were conveyed to the processing plant where they were classified by diameters into five groups: 1st (19mm). The asparagus was washed, sliced at 21 cm from the tip and divided into three portions: portion 1 of tip (1/3 of the total length), portion 2 of intermediate (1/3 of the total length) and portion 3 of remainder of asparagus (1/3 of the total length). Each portion was placed on filter paper to eliminate excess moisture. Once dry, each sample was weighed (20 g) and dried in an oven at 80°C. 0265-203X/90 $3.00©1990 Taylor & Francis Ltd.
Downloaded by [Universite Laval] at 17:58 13 November 2015
382
G. Zurera-Cosano et al.
Chemical analysis For analysis of asparagus samples, the technique described by Zurera-Cosano et al. (1989) was followed. One gram of the dried sample was taken and ashed, and the ash was extracted with 5 ml of a mixture of concentrated HC1 and HNO3 in a ratio of 1:1 v/v and filtered through Whatman GF/C paper. The filtrate was placed in a 15 ml volumetric flask made up to volume with the deionized water. The determinations were performed with a Perkin-Elmer Model 2380 atomic absorption spectrophotometer. A 10 cm 1-slot burner head and standard airacetylene flame, and wavelength of 228-8 nm and 283-3 nm for cadmium and lead respectively were used. Single element hollow cathode lamps were used for all elements. The instrument settings and other experimental conditions were in accordance with the manufacturer's specifications. The sensitivity obtained was 0-015 mg/1 and 0-319 mg/1 for cadmium and lead respectively. The mean recoveries for asparagus were Cd = 90% and Pb = 96%. For the calculation of the detection limit (Xbiank + 3SD) the criteria of the American Chemical Society (1980) and Mottola (1984) were followed. The concentration limits obtained (minimum concentrations detectable in fresh weight) were 0-004 mg/kg and 0-049 mg/kg for cadmium and lead respectively. Statistical analysis Data obtained from the chemical analysis of the samples were evaluated statistically using two-factor variance, analysis with Scheffe multiple range test (Snedecor and Cochram 1971). Results and discussion
The results are summarized in table 1. All data obtained from analyses of the asparagus samples are shown as fresh weight. Moisture content of the fresh products was determined to constant weight. The mean moisture content of the fresh asparagus was 92-4 with a standard deviation of ± 1-07. The cadmium levels are similar to those found in other vegetable species (Zurera et al. 1987, Zurera-Cosano and Moreno-Rojas 1989), and we consider that the asparagus analysed shows slight contamination of cadmium. In the case of lead, mean levels are similar to those found in a previous work (Zurera-Cosano and Moreno-Rojas 1989). Catalâ et al. (1977) found a mean level of 0-05 mg/kg in fresh asparagus. The mean level of lead found in the total of the Table 1. Concentration of cadmium and lead in asparagus". Cadmium
Lead
Diameter (mm)
n
Tip
Central
Rest
Total
Tip
Central
Rest
Total
19
72
0-020
0-013
0-013
0-015
0-20
0-12
0-14
0-15
Total
213
0-027
0-019
0-021
0-022
0-20
0-14
0-15
0-16
a
mg/kg of fresh weight.
Downloaded by [Universite Laval] at 17:58 13 November 2015
Cadmium and lead in asparagus
383
asparagus samples analysed (0· 165 ± 0·066 mg/kg) rules out the existence of any major environmental-type pollution (air and rain) and rather indicates contamination coming from the soil used for growing. This is natural if it is taken into account that the asparagus is totally covered by soil until it is harvested, and it undoubtedly absorbs heavy metals from the soil. On the other hand, in a previous study (Zurera et al. 1987) it has been pointed out that the contamination by lead and cadmium of other vegetables is produced to a greater degree through aerial zones rather than through the root. By means of a two factor analysis of variance, the existence of statistically significant differences (p < 0-001) in the concentration of lead and cadmium among the five diameters and between the three portions is observed. Scheffe multiple range test was used to establish the homogeneous groups for the five diameters and for the three portions. Figures 1 and 2 show the lead and cadmium distribution for the mean factor of portions and diameters. For lead, statistically significant differences were found between diameter 1 and 2 and between these two and diameters 3, 4, 5. Diameter 1 (
ISSN: 0265-203X (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/tfac19
Cadmium and lead distribution in fresh asparagus G. Zurera‐Cosano , R. Moreno‐Rojas & M. A. Amaro‐Lopez To cite this article: G. Zurera‐Cosano , R. Moreno‐Rojas & M. A. Amaro‐Lopez (1990) Cadmium and lead distribution in fresh asparagus, Food Additives & Contaminants, 7:3, 381-385, DOI: 10.1080/02652039009373903 To link to this article: http://dx.doi.org/10.1080/02652039009373903
Published online: 10 Jan 2009.
Submit your article to this journal
Article views: 7
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tfac20 Download by: [Universite Laval]
Date: 13 November 2015, At: 17:58
FOOD ADDITIVES AND CONTAMINANTS, 1990, VOL. 7, NO. 3, 381-385
Cadmium and lead distribution in fresh asparagus G. ZURERA-COSANO, R. MORENO-ROJAS and M. A. AMARO-LOPEZ Department of Food Hygiene and Technology, University of Cordoba, Medina Azahara, 9. 14005 Cordoba, Spain
Downloaded by [Universite Laval] at 17:58 13 November 2015
(Received 17 July 1989; revised 18 September 1989; accepted 29 September 1989) Cadmium and lead were determined in fresh asparagus, as a function of diameter and portions, by atomic absorption spectrophotometry to evaluate the contribution of these vegetables to the daily intake of cadmium and lead in Spain. Cadmium content of the asparagus ranged from less than 0·006 mg/kg to 0.062 mg/kg, whereas lead content varied from 0·059 to 0.409 mg/kg. The concentration of cadmium and lead was compared statistically for the different diameters and portions of asparagus. The asparagus tip/remainder ratio metal concentration was determined and a greater concentration of cadmium and lead in the tip relative to the remainder of the asparagus was observed. If we take into account the mean level of cadmium and lead (0.022 mg/kg and 0.165 mg/kg respectively), the daily intake contribution of these metals in Spain is 0.04 µg/day for cadmium and 0.3 µg/day for lead. Keywords: Cadmium, lead, heavy metals, asparagus
Introduction
Heavy metal contamination of agricultural land is widely recognized as a potential problem for human health. Cadmium and lead are toxic substances which accumulate in the body due to their low rate of elimination. Determination of traces of heavy metals in vegetables has assumed considerable importance in recent years (Lopez etal. 1986, Zurera et al. 1987), but little has been done to show the effect of the diameter and portion factors in the heavy metal content of asparagus. The purpose of this work was to determine and compare the concentration of lead and cadmium in fresh asparagus, and to determine if the distribution of these elements was a function of diameter and/or portion. At the same time the contribution of asparagus to the daily intake of cadmium and lead in Spain was evaluated. Material and methods
Samples Samples of asparagus were obtained from Egnolac, S.A., Palma del Rio (Spain) and processed in our pilot-plant. The asparagus were conveyed to the processing plant where they were classified by diameters into five groups: 1st (19mm). The asparagus was washed, sliced at 21 cm from the tip and divided into three portions: portion 1 of tip (1/3 of the total length), portion 2 of intermediate (1/3 of the total length) and portion 3 of remainder of asparagus (1/3 of the total length). Each portion was placed on filter paper to eliminate excess moisture. Once dry, each sample was weighed (20 g) and dried in an oven at 80°C. 0265-203X/90 $3.00©1990 Taylor & Francis Ltd.
Downloaded by [Universite Laval] at 17:58 13 November 2015
382
G. Zurera-Cosano et al.
Chemical analysis For analysis of asparagus samples, the technique described by Zurera-Cosano et al. (1989) was followed. One gram of the dried sample was taken and ashed, and the ash was extracted with 5 ml of a mixture of concentrated HC1 and HNO3 in a ratio of 1:1 v/v and filtered through Whatman GF/C paper. The filtrate was placed in a 15 ml volumetric flask made up to volume with the deionized water. The determinations were performed with a Perkin-Elmer Model 2380 atomic absorption spectrophotometer. A 10 cm 1-slot burner head and standard airacetylene flame, and wavelength of 228-8 nm and 283-3 nm for cadmium and lead respectively were used. Single element hollow cathode lamps were used for all elements. The instrument settings and other experimental conditions were in accordance with the manufacturer's specifications. The sensitivity obtained was 0-015 mg/1 and 0-319 mg/1 for cadmium and lead respectively. The mean recoveries for asparagus were Cd = 90% and Pb = 96%. For the calculation of the detection limit (Xbiank + 3SD) the criteria of the American Chemical Society (1980) and Mottola (1984) were followed. The concentration limits obtained (minimum concentrations detectable in fresh weight) were 0-004 mg/kg and 0-049 mg/kg for cadmium and lead respectively. Statistical analysis Data obtained from the chemical analysis of the samples were evaluated statistically using two-factor variance, analysis with Scheffe multiple range test (Snedecor and Cochram 1971). Results and discussion
The results are summarized in table 1. All data obtained from analyses of the asparagus samples are shown as fresh weight. Moisture content of the fresh products was determined to constant weight. The mean moisture content of the fresh asparagus was 92-4 with a standard deviation of ± 1-07. The cadmium levels are similar to those found in other vegetable species (Zurera et al. 1987, Zurera-Cosano and Moreno-Rojas 1989), and we consider that the asparagus analysed shows slight contamination of cadmium. In the case of lead, mean levels are similar to those found in a previous work (Zurera-Cosano and Moreno-Rojas 1989). Catalâ et al. (1977) found a mean level of 0-05 mg/kg in fresh asparagus. The mean level of lead found in the total of the Table 1. Concentration of cadmium and lead in asparagus". Cadmium
Lead
Diameter (mm)
n
Tip
Central
Rest
Total
Tip
Central
Rest
Total
19
72
0-020
0-013
0-013
0-015
0-20
0-12
0-14
0-15
Total
213
0-027
0-019
0-021
0-022
0-20
0-14
0-15
0-16
a
mg/kg of fresh weight.
Downloaded by [Universite Laval] at 17:58 13 November 2015
Cadmium and lead in asparagus
383
asparagus samples analysed (0· 165 ± 0·066 mg/kg) rules out the existence of any major environmental-type pollution (air and rain) and rather indicates contamination coming from the soil used for growing. This is natural if it is taken into account that the asparagus is totally covered by soil until it is harvested, and it undoubtedly absorbs heavy metals from the soil. On the other hand, in a previous study (Zurera et al. 1987) it has been pointed out that the contamination by lead and cadmium of other vegetables is produced to a greater degree through aerial zones rather than through the root. By means of a two factor analysis of variance, the existence of statistically significant differences (p < 0-001) in the concentration of lead and cadmium among the five diameters and between the three portions is observed. Scheffe multiple range test was used to establish the homogeneous groups for the five diameters and for the three portions. Figures 1 and 2 show the lead and cadmium distribution for the mean factor of portions and diameters. For lead, statistically significant differences were found between diameter 1 and 2 and between these two and diameters 3, 4, 5. Diameter 1 (
