World Bank Africa Centre of Excellence in Public Health and Toxicological Research (PUTOR), and Toxicology Unit, Faculty of Pharmacy, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria.
Department of Medical Laboratory Science, Faculty of Science, Rivers State University of Science and Technology Port Harcourt, Port Harcourt, Rivers State, Nigeria.
Environ Geochem Health. 2020 Nov;42(11):3865-3875. doi: 10.1007/s10653-020-00632-0. Epub 2020 Jun 30.
Geophagy is a cultural behavior, based on the recurrent intentional eating of clay soil, that is raising increasing concern as it implies multidimensional (space, time) potential risk of serious adverse health effects. This study investigated the level of toxic metals (Cd and Pb) in 20 Nigerian geophagic clays intended for both local consumption and distribution to the West Africa market. After sampling in 4 open markets in southern Nigeria (Akwa Ibom, Abia, Rivers, Imo), samples were subjected to digestion, ashing and analysis. The Pb levels in all samples exceeded the WHO/FAO maximum permissible limit of 0.1 mg kg whereas 16% exceeded the Cd limit of 0.3 mg kg. The estimated daily intake of Pb for all samples ranged from 0.0032-0.0286 mg kg day to 0.0024-0.0215 mg kg day for children and adults, respectively. The estimated daily intakes for Cd ranged from bdl (below detection limit)-0.0010 mg kg day to bdl-0.0028 mg kg day for children and adults, respectively. In both cases, the WHO/FAO provisional Tolerable Weekly Intake is exceeded through the ingestion of these soils. Our results confirm health risks related to the geophagic practices, its role in exceeding health guidelines when considering aggregate exposure in the Nigerian scenario and body burden in developing organisms, young women, women at fertile age, and pregnant women. We discuss how geophagists consider clays as traditional nutraceuticals and how clarifying the nutraceutical role of geophagy could facilitate risk communication. Geophagic products are implicitly or explicitly marketed as dietary supplements, and as such they should be regulated (1) by labeling, and prohibition of scientifically unfounded health claims and (2) by safety standards before marketing. This is particularly critical when clays originate from countries living rapid, unplanned and uncontrolled development and dumped, like Nigeria.
食土癖是一种文化行为，基于反复故意食用粘土，由于涉及多维度（空间、时间）的严重不良健康影响的潜在风险，因此引起了越来越多的关注。本研究调查了 20 种尼日利亚食用性粘土中的有毒金属（Cd 和 Pb）水平，这些粘土既用于当地消费，也用于供应西非市场。在尼日利亚南部的 4 个开放市场（阿克瓦伊博姆州、阿比亚州、里弗斯州和伊莫州）进行采样后，对样品进行了消化、灰化和分析。所有样品中的 Pb 含量均超过世界卫生组织/粮农组织规定的 0.1mg/kg 的最大允许限量，而有 16%的样品超过了 0.3mg/kg 的 Cd 限量。所有样品的 Pb 日摄入量估计值范围为 0.0032-0.0286mg/kg·天至 0.0024-0.0215mg/kg·天，分别为儿童和成人的摄入量。Cd 的日摄入量估计值范围为 bdl（低于检测限）-0.0010mg/kg·天至 bdl-0.0028mg/kg·天，分别为儿童和成人的摄入量。在这两种情况下，通过摄入这些土壤，均超过了世界卫生组织/粮农组织暂定可耐受每周摄入量。我们的研究结果证实了与食土癖相关的健康风险，以及在考虑尼日利亚的综合暴露和发育中生物体的体内负荷时，食土癖可能会超过健康指导原则。年轻女性、育龄妇女和孕妇。我们讨论了食土者如何将粘土视为传统的营养保健品，以及阐明食土癖的营养保健品作用如何促进风险沟通。食土癖产品被隐含或明确地作为膳食补充剂进行营销，因此应（1）通过标签进行监管，禁止未经科学证实的健康声明，以及（2）在营销前制定安全标准。当粘土来自像尼日利亚这样快速、无计划和不受控制发展和倾销的国家时，这一点尤其关键。
