The sources and chemical content of edible soil sticks sold in markets in Tanzania: a cross-sectional analytical study
The sources and chemical content of edible soil sticks sold in markets in Tanzania: a cross-sectional analytical study
复制标题
DOI：
10.1007/s10653-018-0185-x
复制
发表时间：
2019-04-01
影响因子：
4.2
通讯作者：
Dewey, Deborah
中科院分区：
文献类型：
--
作者：
Msoffe, Charisma U.;Nyanza, Elias C.;Dewey, Deborah
食土癖在包括坦桑尼亚在内的许多国家都很常见。研究报告了食用土壤中不同化学物质的水平，其中一些可能对食土者的健康有害。在撒哈拉以南非洲的许多市场上都可以买到被称为奔巴的食用干土棒，但很少有研究确定这些土壤的来源。本研究的目的是：（1）使用全球定位系统（GPS）系统地记录坦桑尼亚区域市场上通常销售的奔巴所用土壤的来源，以确定奔巴流向市场的供应链，以及（2）评估土壤来源的水提取化学元素（WEC）和总化学元素（TC）含量。在坦桑尼亚大陆的区域市场进行了调查，以确定市售土壤棒中常用的土壤来源。然后，从坦桑尼亚12个地区的确定来源收集土壤样品，并使用电感耦合等离子体质谱实验室技术分析WEC和TC含量。奔巴土壤的开采局限于12个地区。对供应链流程的分析显示，一个完善的分销网络确保了土壤棒在全国各地的运输和销售。在不同浓度下检测必需和微量元素（Ca、Fe、K、Mg、Na、Mn、Co、Cr、V、Mo、Cu和Zn）和有毒元素（Al、As、Ba、Cd、Ni和Pb）的WEC和TC。根据世界卫生组织和美国有毒物质和疾病登记局指定的口服最大耐受限度，大多数微量和有毒元素均高于正常范围。这是坦桑尼亚第一次在全国范围内大规模记录和检查商业土壤棒的来源土壤位置的研究。研究结果表明，食土行为可能是有毒元素的一个重要暴露途径。
Geophagy, or eating soil, is common in various countries including Tanzania. Studies have reported on the levels of different chemicals in consumed soil, some of which can be harmful to the health of individuals practicing geophagy. Dried soil sticks for eating, referred to as pemba, are commercially available in many markets in sub-Saharan Africa, but few studies have established the sources of the soils. The purpose of the current study was to: (1) systematically document the sources of the soils used in pemba commonly sold in regional markets throughout Tanzania using a global positioning system (GPS) to establish the supply chain flow of pemba to markets, and (2) assess the chemical element content of the soil sources for both water-extractable chemical element (WEC) and total chemical element (TC) contents. Surveys were conducted at regional markets across mainland Tanzania to identify the sources of soils commonly used in commercially available soil sticks. Then, soil samples were collected from identified sources in 12 regions across Tanzania and analyzed for WEC and TC content using an inductively coupled plasma mass spectrometry laboratory technique. Mining of the pemba soil was localized in 12 regions. Analysis of the supply chain flow revealed a well-established distribution network that ensured transportation and marketing of the soil sticks to regions throughout the country. WEC and TC of essential and trace elements (Ca, Fe, K, Mg, Na, Mn, Co, Cr, V, Mo, Cu, and Zn) and toxic elements (Al, As, Ba, Cd, Ni, and Pb) were detected at varying concentrations. Most of the trace and toxic elements were above the normal range, based on the oral maximum tolerable limits designated by the World Health Organization and US Agency for Toxic Substance and Disease Registry. This is the first study in Tanzania to document and examine the source soil locations for commercially available soil sticks at the macroscale across the entire country. The findings suggest that geophagy could be a significant exposure pathway for toxic elements.