Does arsenic pose a health concern after consumption of clay products?

Clay products for oral use form a particular group of food supplements in relation to potential arsenic (As) toxicity, because – certainly in case of pure clay- all arsenic in these supplements is expected to be present in the most toxic inorganic form (As_i). In terms of risk, the most important questions to answer relate to the bioaccessibility and bioavailability of the inorganic arsenic present, rather than to the As species distribution, which often receives most attention in standard foodstuffs. In the present study, clay products for oral use were bought on the Belgian market and analysed for total arsenic (As_tot), arsenic species (As_i, arsenobetaine, dimethylarsenate and monomethylarsenate)) and bioaccessible arsenic, in order to perform an exposure assessment and risk characterisation. Total As concentrations differed considerably between the samples and ranged from 0.20 to 6.4 mg As_tot/kg. Bioaccessibility of As_i, determined via the Unified Barge Method (extraction making use of digestive enzymes) varied between 8% and 51%. The As_i concentration determined via HPLC-ICP-MS after extraction with diluted HNO₃ +H₂O₂ (as in the CEN method for foodstuffs) was only a poor predictor of the bioaccessible As_i fraction, despite the significant relationship (R² = 0.36; <i>p</i> &lt; .05). The risk characterisation did not reveal acute risks related to As_i exposure. However, a potential concern with regard to chronic As_i intake was identified for the general population in 42% of the analysed food supplements, and for sensitive population groups in 67% of the samples, even after taking into account the bioaccessible fraction. The data presented illustrate that consumption of some of these clay products may contribute significantly to dietary As_i intake and that these should not be taken chronically.口服用黏土制品属于一类与潜在砷（arsenic, As）毒性相关的特殊食品补充剂，这是因为——在纯黏土的情况下——这类补充剂中的全部砷均以毒性最强的无机砷（inorganic arsenic, As_i）形态存在。就风险评估而言，需要明确的核心问题是该类补充剂中无机砷的生物可及性（bioaccessibility）与生物可利用性（bioavailability），而非标准食品中通常备受关注的砷形态分布。本研究从比利时市场采购了口服用黏土制品，并对其总砷（total arsenic, As_tot）、砷形态（As_i、砷甜菜碱（arsenobetaine）、二甲基胂酸（dimethylarsenate）及一甲基胂酸（monomethylarsenate））以及生物可及性砷进行了分析，以开展暴露评估与风险表征。不同样品的总砷浓度差异显著，范围为0.20~6.4 mg As_tot/kg。经基于消化酶提取的统一Barge法（Unified Barge Method）测定的无机砷生物可及性介于8%~51%之间。采用稀释硝酸（HNO₃）+过氧化氢（H₂O₂）提取（参照食品检测的欧洲标准化委员会（Comité Européen de Normalisation, CEN）方法）后，经高效液相色谱-电感耦合等离子体质谱法（HPLC-ICP-MS）测定的无机砷浓度，仅能较弱地预测生物可及性无机砷组分，尽管二者存在显著相关性（决定系数R²=0.36；*p*<0.05）。风险表征结果未显示与无机砷暴露相关的急性风险。然而，即便考虑生物可及性组分，在42%的受试食品补充剂中，普通人群仍存在慢性无机砷摄入的潜在风险隐患；在67%的样品中，敏感人群则面临此类潜在担忧。本次研究的数据表明，部分此类黏土制品的摄入可能会显著增加膳食无机砷摄入量，因此不建议长期服用。