Heavy metal contamination of agricultural soil and countermeasures in Japan

Abstract

Soil is a complex structure and contains mainly five major components i.e. mineral matter, water, air, organic matter and living organisms. The quantity of these components in the soil does not remain the same but varies with the locality. Soil possesses not only a nucleus position for existence of living being but also ensures their future existence. Therefore, it is essential to make an adequate land management to maintain the quality of soil in both rural and urban soil. The presence of different kinds of heavy metals such as Cd, Cu, Mn, Bi and Zn etc. in trace or in minimum level is a natural phenomenon but their enhanced level is an indicator of the degree of pollution load in that specific area. The precise knowledge of these kinds of heavy metals, their forms and their dependence on soil provides a genuine base for soil management. The heavy metals have potent cumulative properties and toxicity due to which they have a potential hazardous effect not only on crop plants but also on human health. The metal contaminants can be reduced by immobilization of contaminants using macrophytes and also by using genetically engineered microorganisms.

Contributing to food security in urban areas: differences between urban agriculture and peri-urban agriculture in the Global North

“…Soil nutrient status in PUA is generally affected by the way in which it is farmed. Still, PUA can be negatively impacted by urban air pollution (Heimlich and Anderson 2001) or affected by other industries, such as mining close to urban areas (Arao et al 2010). Soil-free cultivation is also applied within PUA in greenhouses either on substrate (Korthals Altes and van Rij 2013) or hydroponics, for example in the Greater London area (Garnett 2001).…”

Effects of water management on arsenic and cadmium speciation and accumulation in an upland rice cultivar

“…Cd is a highly toxic heavy metal which can readily accumulate in crops and thus lead to chronic toxicity diseases in livestock and humans. Contamination of agricultural soils by Cd and As has become an important issue as a result of industrial activities in the proximity of agricultural areas, excessive application of contaminated fertilizers, manures and sewage sludges, and irrigation with water contaminated with metal(loid)s (Roberts et al, 2007;Chen et al, 2008;Williams et al, 2009;Arao et al, 2010). Rice, the most important staple food in Asia, is considered to be a major source of Cd and As in the human diet in some parts of Japan, India and China (Tsukahara et al, 2003;Mondal and Polya, 2008;Liang et al, 2010).…”

Detection of a QTL for accumulating Cd in rice that enables efficient Cd phytoextraction from soil

“…Rice has well-established cultivation and mechanized harvesting systems, both of which are necessary for the development of a successful phytoextraction technology. In addition, an incineration system has been developed to dispose of harvested rice plants containing Cd (Arao et al 2010).…”

“…However, the genetic characteristics of the high-Cd trait of Jarjan and the phytoextraction efficiency of the previously reported QTLs for high Cd uptake were not analyzed in earlier studies. It is well known that rice Cd uptake is greatly influenced by various soil properties such as soil type, soil Cd concentration, soil pH, carbon content, and coexistence of other heavy metals (Arao et al 2010). Therefore, candidate QTLs for Cd phytoextraction should be detected and evaluated in various soil environments to confirm their stability across environmental conditions.…”