Joakim Engman

Accumulation of cadmium from wheat bran, sugar-beet fibre, carrots and cadmium chloride in the liver and kidneys of mice

The gastrointestinal absorption and organ distribution of Cd after exposure for 9 weeks to three fibre-rich foodstuffs (wheat bran, sugar-beet fibre and carrots) were determined in mice. Groups of eight mice were given a diet containing 0.05 mg Cd/kg from wheat bran, sugar-beet fibre, carrots or CdCl2 mixed in a semi-synthetic, low-Cd (< 0.007 mg/kg) feed. A control group was fed on the low-Cd semi-synthetic feed. The water consumption, food consumption and the weight of the animals were monitored throughout the study. The feed was changed once weekly and Cd was analysed in the feed at each change. myo-Inositol phosphates (hexa-, penta-, tetra- and tri-) and Zn, Cu, Fe and Ca were also analysed in the diets. After 9 weeks, the mice were killed and liver and kidneys were sampled and analysed for Cd. The group receiving the wheat-bran diet had significantly lower fractional Cd accumulation (% total Cd intake) in the liver and kidneys than the other groups, indicating a lower fractional absorption of Cd. The wheat-bran diet had markedly higher levels of inositol hexa- and pentaphosphates (phytates) and a Zn level that was twice as high as those in the other diets. The higher levels of myo-inositol hexa- and pentaphosphates in the wheat-bran diet most probably contributed more to the lower fractional absorption of Cd than the elevated Zn level, due to the formation of insoluble Cd-phytate complexes. Compared with the wheat-bran diet, the sugar-beet-fibre and carrot diets contained very low levels of myo-inositol penta- and hexaphosphates, and consequently the fractional Cd absorption from these diets was higher.

Cadmium accumulation in liver and kidney of mice exposed to the same weekly cadmium dose continuously or once a week

Cd levels in blood, liver and kidney of female mice were measured after exposure to Cd as CdCl2 in the food, either continuously (CE group) throughout the week (300 microg Cd/kg feed) or for 24 hr/wk (2100 microg Cd/kg) for 5 wk (occasionally exposed, OE group). In a control group that received feed with Cd levels below the detection limit (< 7 microg/kg), Cd levels in blood, liver and kidneys were below the detection limit after the 5 wk of exposure. The weekly dose of Cd administered to the exposed CE and OE groups was similar (approx. 400 microg Cd/kg mice/wk). The OE group had a higher Cd level in blood and a higher fractional accumulation (% of dose) of Cd in the liver and kidneys compared with the CE group. This indicates that the fractional Cd absorption in the gastrointestinal tract is higher when high Cd doses are ingested occasionally than when low doses are ingested continuously, even if weekly doses are the same. It is hypothesized that this difference in absorption could be due to Cd-induced unspecific damage to the intestinal mucosa, changes in tight-junction permeability caused by Cd, or to a saturation of the Cd-binding capacity of the intestinal mucosa in mice exposed to high Cd levels occasionally.

Trace elements in crayfish: Regional differences and changes induced by cooking

The concentrations of Pb, Cd, Zn, Cu, Ni, Cr, Mn, Co, As, and Se were determined in the abdominal muscle and hepatopancreas from raw and cooked crayfish of Astacus astacus (L.) and Pacifastacus leniusculus (Dana), both of Swedish origin. After cooking, the concentrations of Cd, Ni, and Co in the hepatopancreas showed a decrease and the concentrations of Pb, Cu, and Mn in the abdominal muscle showed an increase. Metal and metalloid concentrations were also determined in the abdominal muscle and hepatopancreas of commercially caught and cooked crayfish, including Astacus leptodactylus (Esch.) and Procambarus clarkii (Girard), from China, Spain, Sweden, Turkey, and USA. Most of the elements showed little variation except for cadmium in the abdominal muscle of P. leniusculus from California, which was markedly higher (mean=0.082 mg/kg) than the others (mean=0.004 mg/kg). Metal and metalloid concentrations in hepatopancreas varied greatly within as well as between countries. In the hepatopancreas from P. leniusculus from a Swedish lake the manganese concentrations were markedly higher than in any other crayfish. The intake of cadmium from crayfish inhabiting uncontaminated waters will be low if the hepatopancreas is not consumed.

BIOAVAILABILITY OF CADMIUM FROM CRAB HEPATOPANCREAS AND MUSHROOM IN RELATION TO INORGANIC CADMIUM - A 9-WEEK FEEDING STUDY IN MICE

The bioavailability of Cd from boiled crab hepatopancreas and dried mushroom was studied in relation to that of inorganic Cd (CdCl2). Female Balb/c mice were fed with diets containing 0.4 ppm Cd from either boiled crab (Cancer pagurus) hepatopancreas or dried mushroom (Agaricus augustus), or as inorganic Cd (CdCl2). A control group received low Cd (< 0.007 ppm) feed, and did not accumulate detectable levels of Cd during 9 wk of exposure. Using Cd accumulation in the liver and kidney as a measure of Cd absorption, it was indicated that the bioavailability of Cd from boiled crab hepatopancreas is slightly lower than that of Cd from mushroom and inorganic Cd. Fractionation of Cd in boiled crab hepatopancreas and mushroom indicated that Cd in crab hepatopancreas mainly is associated with denaturated proteins with low solubility, whereas a large fraction of Cd in dried mushroom is associated with soluble ligands. This difference in speciation of Cd may be a reason for the lower bioavailability of crab Cd than that of mushroom Cd. The difference in bioavailability is, however, low and as a safety measure it is recommended that human consumption of both crab hepatopancreas and wild mushrooms with high Cd levels should be restricted.

Toxic and essential elements in fish from Nordic waters, with the results seen from the perspective of analytical quality assurance

Fish from fresh, brackish and marine waters were analysed for their levels of Pb, Cd, Cr, Ni, Co, Zn, Cu, Mn, As and Se in muscle tissue. Various quality control procedures were implemented during the survey and the results were compared with those from several other surveys, most of which were carried out during the 1990s. It was noted that several elements varied widely both within and between studies. A systematic examination of a large number of surveys and ranking of their quality level indicated that a lack of quality control procedures often results in high or varying results. This may have serious consequences when results are used as a basis for for example, legislation or intake recommendations.

Levels of certain trace elements in beef and pork imported to Sweden

The levels of Pb, Cd, Ni, Cr, Co, Zn, Cu, Mn, As and Se were determined in beef and pork imported to Sweden from six different countries. Samples of Swedish beef and pork were included for comparison. The results of this survey showed in most cases little difference in levels of these elements between the countries and agreed well with the results from our previous studies. All results for Pb, Cd, Ni and As were below the detection limits of 0.007, 0.001, 0.016 and 0.030 mg/kg fresh weight, respectively. Chromium and cobalt were, in both beef and pork, close to, or below, the detection limits of 0.004 and 0.003 mg/kg fresh wt, respectively. The level of selenium in beef varied considerably between countries, from < 0.030 to 0.18 mg/kg fresh wt. The levels of lead and cadmium from this study differed strongly in some cases from what have been reported in surveys from several countries, among them some countries exporting to Sweden. The importance of a rigorous quality control programme is emphasized.

Uptake of lead by vegetables grown in contaminated soil.

Potatoes, carrots, beetroots, lettuce and rhubarb were cultivated on soil, that had been severely lead-contaminated by industrial activities at three different locations in Sweden. The vegetables were grown in the gardens of people living in the district, or in some other way making use of the land in the contaminated areas. In some cases, the vegetables were grown in a greenhouse in pots filled with soil from the contaminated sites. Samples of vegetables and soil were collected simultaneously. The vegetables were dry ashed at 450°C and analysed for lead using graphite furnace atomic absorption spectrophotometry with background correction. Certified reference materials were analysed simultaneously with the samples. Soils were extracted according to two methods based on extraction with 2 M HNO 3 and NH 4 OAc, respectively. Lead was determined as above. The pH was determined in a filtered mixture of soil and water (1:2) and recalculated to H + . The results for both vegetables and soils spanned over quite a wide range, for vegetables between < 0.004 and 2.7 mg/kg fresh weight. In the soils, the results ranged from 9.6 to 4400 mg/kg dry weight for the HNO 3 fraction, and from 2.3 to 478 mg/kg for the NH 4 OAc fraction. Regression analysis showed a significant positive correlation (p<0.05) between lead levels in all the vegetables and lead levels in both of the soil fractions together with H + .Abstract Potatoes, carrots, beetroots, lettuce and rhubarb were cultivated on soil, that had been severely lead‐contaminated by industrial activities at three different locations in Sweden. The vegetables were grown in the gardens of people living in the district, or in some other way making use of the land in the contaminated areas. In some cases, the vegetables were grown in a greenhouse in pots filled with soil from the contaminated sites. Samples of vegetables and soil were collected simultaneously. The vegetables were dry ashed at 450°C and analysed for lead using graphite furnace atomic absorption spectrophotometry with background correction. Certified reference materials were analysed simultaneously with the samples. Soils were extracted according to two methods based on extraction with 2 M HNO3 and NH4OAc, respectively. Lead was determined as above. The pH was determined in a filtered mixture of soil and water (1:2) and recalculated to H+. The results for both vegetables and soils spanned over quite a wide range, for vegetables between < 0.004 and 2.7 mg/kg fresh weight. In the soils, the results ranged from 9.6 to 4400 mg/kg dry weight for the HNO3 fraction, and from 2.3 to 478 mg/kg for the NH4OAc fraction. Regression analysis showed a significant positive correlation (p<0.05) between lead levels in all the vegetables and lead levels in both of the soil fractions together with H+.

Applications in food quality and environmental contamination

Potatoes, carrots, beetroots, lettuce and rhubarb were cultivated on soil, that had been severely lead-contaminated by industrial activities at three different locations in Sweden. The vegetables were grown in the gardens of people living in the district, or in some other way making use of the land in the contaminated areas. In some cases, the vegetables were grown in a greenhouse in pots filled with soil from the contaminated sites. Samples of vegetables and soil were collected simultaneously. The vegetables were dry ashed at 450°C and analysed for lead using graphite furnace atomic absorption spectrophotometry with background correction. Certified reference materials were analysed simultaneously with the samples. Soils were extracted according to two methods based on extraction with 2 M HNO 3 and NH 4 OAc, respectively. Lead was determined as above. The pH was determined in a filtered mixture of soil and water (1:2) and recalculated to H + . The results for both vegetables and soils spanned over quite a wide range, for vegetables between < 0.004 and 2.7 mg/kg fresh weight. In the soils, the results ranged from 9.6 to 4400 mg/kg dry weight for the HNO 3 fraction, and from 2.3 to 478 mg/kg for the NH 4 OAc fraction. Regression analysis showed a significant positive correlation (p<0.05) between lead levels in all the vegetables and lead levels in both of the soil fractions together with H + .Abstract Potatoes, carrots, beetroots, lettuce and rhubarb were cultivated on soil, that had been severely lead‐contaminated by industrial activities at three different locations in Sweden. The vegetables were grown in the gardens of people living in the district, or in some other way making use of the land in the contaminated areas. In some cases, the vegetables were grown in a greenhouse in pots filled with soil from the contaminated sites. Samples of vegetables and soil were collected simultaneously. The vegetables were dry ashed at 450°C and analysed for lead using graphite furnace atomic absorption spectrophotometry with background correction. Certified reference materials were analysed simultaneously with the samples. Soils were extracted according to two methods based on extraction with 2 M HNO3 and NH4OAc, respectively. Lead was determined as above. The pH was determined in a filtered mixture of soil and water (1:2) and recalculated to H+. The results for both vegetables and soils spanned over quite a wide range, for vegetables between < 0.004 and 2.7 mg/kg fresh weight. In the soils, the results ranged from 9.6 to 4400 mg/kg dry weight for the HNO3 fraction, and from 2.3 to 478 mg/kg for the NH4OAc fraction. Regression analysis showed a significant positive correlation (p<0.05) between lead levels in all the vegetables and lead levels in both of the soil fractions together with H+.

Applications in food quality and environmental contamination: Uptake of lead by vegetables grown in contaminated soil

Potatoes, carrots, beetroots, lettuce and rhubarb were cultivated on soil, that had been severely lead-contaminated by industrial activities at three different locations in Sweden. The vegetables were grown in the gardens of people living in the district, or in some other way making use of the land in the contaminated areas. In some cases, the vegetables were grown in a greenhouse in pots filled with soil from the contaminated sites. Samples of vegetables and soil were collected simultaneously. The vegetables were dry ashed at 450°C and analysed for lead using graphite furnace atomic absorption spectrophotometry with background correction. Certified reference materials were analysed simultaneously with the samples. Soils were extracted according to two methods based on extraction with 2 M HNO 3 and NH 4 OAc, respectively. Lead was determined as above. The pH was determined in a filtered mixture of soil and water (1:2) and recalculated to H + . The results for both vegetables and soils spanned over quite a wide range, for vegetables between < 0.004 and 2.7 mg/kg fresh weight. In the soils, the results ranged from 9.6 to 4400 mg/kg dry weight for the HNO 3 fraction, and from 2.3 to 478 mg/kg for the NH 4 OAc fraction. Regression analysis showed a significant positive correlation (p<0.05) between lead levels in all the vegetables and lead levels in both of the soil fractions together with H + .Abstract Potatoes, carrots, beetroots, lettuce and rhubarb were cultivated on soil, that had been severely lead‐contaminated by industrial activities at three different locations in Sweden. The vegetables were grown in the gardens of people living in the district, or in some other way making use of the land in the contaminated areas. In some cases, the vegetables were grown in a greenhouse in pots filled with soil from the contaminated sites. Samples of vegetables and soil were collected simultaneously. The vegetables were dry ashed at 450°C and analysed for lead using graphite furnace atomic absorption spectrophotometry with background correction. Certified reference materials were analysed simultaneously with the samples. Soils were extracted according to two methods based on extraction with 2 M HNO3 and NH4OAc, respectively. Lead was determined as above. The pH was determined in a filtered mixture of soil and water (1:2) and recalculated to H+. The results for both vegetables and soils spanned over quite a wide range, for vegetables between < 0.004 and 2.7 mg/kg fresh weight. In the soils, the results ranged from 9.6 to 4400 mg/kg dry weight for the HNO3 fraction, and from 2.3 to 478 mg/kg for the NH4OAc fraction. Regression analysis showed a significant positive correlation (p<0.05) between lead levels in all the vegetables and lead levels in both of the soil fractions together with H+.

Cadmium absorption in mice: effects of broiling on bioavailability of cadmium in foods of animal origin.

The absorption and organ distribution of organic Cd from raw and broiled horse kidney was compared to that of CdCl2 at two dose levels (0.05 and 3 mg Cd/kg feed) in a feeding study in mice. The high Cd concentration in the horse kidney (raw 112 mg/kg; broiled 53 mg/kg) made it possible to mix kidney into mouse feed without marked effects on the composition of the feed. The weight of the mice, feed and water consumption, and Cd levels in the feed were determined once a week. After 9 wk of exposure, the liver and kidneys of the mice were sampled and Cd was analyzed. The Cd concentration in horse kidney was halved by broiling, and the content of soluble Cd decreased from 12% in raw kidney to 5% in broiled kidney. The majority of the soluble Cd was associated with proteins with the same molecular weight as metallothionein (MT) in both raw and broiled kidney. Broiling of the kidney had no marked effect on the fractional accumulation of organic Cd in mice. The fractional accumulation of inorganic CdCl2, on the other hand, was significantly higher than that of organic Cd in the low dose groups but not in the high dose groups. The ratio between Cd accumulation in kidney and that in liver was higher in the group receiving raw kidney compared to the ratio in the group receiving CdCl2 at both the high and low exposure levels. This indicates that the raw kidney contained a Cd form that was more preferentially distributed to the kidneys.