土壤与人体健康

土壤可以通过多条途径对人体健康产生正面或负面的影响。本文从土壤通过食物链提供人体必需的矿质营养、人体来自于土壤-食物链的有害重金属暴露、以及土壤中抗生素抗性基因传播等方面探讨土壤与人体健康的关系。土壤对人体健康的影响具有非均等性,贫困地区与低收入群体往往更容易受到土壤对人体健康的负面影响。在未来人口增长与全球气候变化双重压力下,土壤与人体健康的关系将变得更为突出。本文还提出了消减土壤对人体健康负面影响的一些干预措施选项及未来的研究方向。

Soil and Human Health

Soil can exert both positive and negative impacts on human health.In this paper,three aspects of the relationship between soil and human health are discussed:1、supply of essential mineral nutrients from soil to humans;2、human’s exposure to toxic heavy metals and metalloids via their transfer from soil to the food chain;and 3、the spread of antibiotic resistance genes in soil.Although soils,through the food chain,are a main source of many essential mineral nutrients for humans,for some nutrients the supply may not meet the requirements of humans,especially those elements that are required by animals but not by plants.Selenium is a typical example,which is deficient in the diets of many people due to low levels of this element in the soil.Agronomic biofortification through additions of selenium in fertilizers is an effective way to increase selenium intake in the population living in the low selenium areas.Human activities have caused contamination of soil with various types of organic and inorganic contaminants.Heavy metals and metalloids such as cadmium and arsenic can be transferred readily from soil to the edible organs of crop plants,posing a risk to human health.Soil contamination coupled with soil acidification has resulted in increased availability of cadmium in soil and elevated accumulation of this toxic metal in food crops.A number of strategies can be used to reduce the accumulation of heavy metals and metalloids in food crops,including methods to immobilize contaminants in soil,cultivar selection,breeding and genetic engineering to reduce heavy metal uptake or translocation in crop plants,phytoextraction of heavy metals and metalloids with hyperaccumulators to clean up contaminated soil.Overuse of antibiotics in humans and in animal production has resulted in increased antibiotic resistance in microorganisms in the environment,which may lead to the evolution of superbugs of human pathogens.Animal manures may contain high levels of antibiotic resistant microbes and resistance genes,which can disseminate into agricultural soil via manure applications.Urgent actions should be taken to control the overuse of antibiotics in animal production.Effective methods are also needed to decrease the abundance and diversity of antibiotic resistance microbes and genes in animal manures before application to soil.It is recognized that the impacts of soil on human health are uneven across the whole population;people living in poor areas or having a low income are often more vulnerable to the negative effects of soil on human health.The relationship between soil and human health will become more prominent in the future with the dual challenges of increasing population and global climate changes.Options to alleviate the negative impacts of soil on human health and future research directions are also discussed.