Helgesen H, Larsen E H
Department of Chemistry, Technical University of Denmark, Lyngby, Denmark.
Analyst. 1998 May;123(5):791-6. doi: 10.1039/a708056e.
Carrots were grown in seven experimental plots (A-G) containing mixtures of arsenic-contaminated and uncontaminated soil at concentrations ranging from 6.5 to 917 microgram g(-1) (dry mass). The carrots harvested from plots A-D (6.5-338 microgram g(-1) arsenic in the soil mixtures) showed a gradually increasing depression of growth with increasing level of contamination. At the experimental plots E-G with soil arsenic concentrations above 400 microgram g(-1) no carrots developed. Whether this effect was caused by arsenic or the concomitant copper content which ranged from 11 to 810 microgram g(-1) in the soil mixtures is unknown. The arsenic species extracted from the soils and carrots were separated and detected using anion-exchange HPLC coupled with ICP-MS. In the less contaminated soils from plots A and B arsenite (AsIII) was more abundant than arsenate (Asv) in the soil using 1 mmole 1-1 calcium nitrate as extractant. In the soils from plots C and D however, Asv dominated over AsIII whereas in the corresponding carrots Asv and AsIII were found at similar concentrations. Methylated arsenic species were sought after but not detected in any of the samples. The soil-to-carrot uptake rate (bioavailability) of arsenic was 0.47 +/- 0.06% (average +/- one standard deviation) of the arsenic content in the soils from plots A-D. In contrast to arsenic, the increasing copper content in the soils from plot A through D was not available to the carrots as the concentration of this element did not increase with increasing soil copper content. The ingestion of the potentially toxic inorganic arsenic via consumption of carrots grown in soil contaminated at 30 microgram g(-1) in arsenic (plot B) was conservatively estimated at 37 microgram week (-1). This was equivalent to only 4% of the provisional tolerable weekly intake (PTWI) for inorganic arsenic as suggested by the WHO and was therefore toxicologically safe. Consumption of carrots grown in more intensely arsenic-contaminated soils, however, would lead to a higher intake of inorganic arsenic and is therefore not recommended.
胡萝卜种植于七个实验地块（A - G），这些地块含有受砷污染和未受污染土壤的混合物，砷浓度范围为6.5至917微克/克（干重）。从A - D地块收获的胡萝卜（土壤混合物中砷含量为6.5 - 338微克/克）显示，随着污染水平的增加，生长抑制逐渐加剧。在土壤砷浓度高于400微克/克的E - G实验地块，未长出胡萝卜。这种影响是由砷还是土壤混合物中含量为11至810微克/克的伴随铜含量引起尚不清楚。使用阴离子交换高效液相色谱与电感耦合等离子体质谱联用技术对从土壤和胡萝卜中提取的砷物种进行分离和检测。在A和B地块污染较轻的土壤中，以1毫摩尔/升硝酸钙作为提取剂时，亚砷酸盐（AsIII）在土壤中的含量比砷酸盐（AsV）更丰富。然而，在C和D地块的土壤中，AsV占主导地位，而在相应的胡萝卜中，AsV和AsIII的浓度相似。虽对甲基化砷物种进行了寻找，但在任何样品中均未检测到。A - D地块土壤中砷的土壤到胡萝卜吸收速率（生物有效性）为土壤中砷含量的0.47±0.06%（平均值±一个标准差）。与砷不同，从A到D地块土壤中不断增加的铜含量对胡萝卜不可用,因为该元素的浓度并未随着土壤铜含量的增加而增加。通过食用在砷含量为30微克/克的污染土壤中种植的胡萝卜（B地块）摄入潜在有毒无机砷的量保守估计为37微克/周。这仅相当于世界卫生组织建议的无机砷暂定每周耐受摄入量（PTWI）的4%，因此在毒理学上是安全的。然而，食用在砷污染更严重的土壤中种植的胡萝卜会导致更高的无机砷摄入量，因此不建议食用。
