Potentially toxic elements concentration in milled rice differ among various planting patterns
Introduction
Increasing soil contamination by the potentially toxic elements (PTEs) has emerged one of the gravest threats to environmental sustainability and global food security (Rodriguez et al., 2007). In China, nearly 19.4% of arable land has been contaminated by PTEs mainly including cadmium, lead, copper, nickel, arsenic, zinc, mercury, and chromium (Jin, 2014). Soil contamination by the PTEs is governed by several factors including solid-waste disposal and atmospheric deposition. Moreover, fertilizers and pesticide use, application of the wastewater irrigation and sewage sludge in the field are also considered as the major cause of PTEs accumulation (Cui et al., 2005, Wilson and Pyatt, 2007). As the PTEs in the plants are taken up from soil, therefore, soil contamination with toxic elements and their transfer from soil to plant have got increasing concern (Zhao et al., 2010).
Rice (Oryza sativa L.) is arguably one of the major staple foods feeding more than half of world's population. In China, it covers 24% of all farm lands accounting 40% of total crop yields (Hu et al., 2002). Moreover, it has been considered as a major source of PTEs intake by humans in Asian countries (Mondal and Polya, 2008, Solidum et al., 2012, Tsukahara et al., 2003). Therefore, the security of rice has attracted more and more attention, in recent years. The increasing rice demand in future has deployed tremendous concerns to minimize PTE contamination for sustainable and productive rice based systems.
Looming water crisis and labor shortage have threatened the traditional transplanted-flooded rice (TFR) system and boosted the direct-seeded rice as alternate establishment method (Liu et al., 2014). However, a series of researches had reported that direct-seeded rice may increase the PTEs concentration in milled rice (Kawasaki et al., 2012, Peng et al., 2012, Zhang et al., 2006). In fact, water management had a significant influence on soil properties, including redox potential, organic matter, pH, and pedogenic oxide (Alloway, 2009, Fu et al., 2008), thus affecting the PTEs uptake by plants (Gao et al., 2012, Spanu et al., 2012). Gao et al. (2012) showed that aerobic soil conditions in dry direct-seeded aerobic rice (DSA) system provided a favorable environment for the activity of mycorrhizal fungi and mycorrhizal inoculation, which could be beneficial for increasing the bioavailability of Zinc (Zn), thus increasing Zn content in rice plants. In consistent with Zn content in rice plant, Cd content in rice plant was also increased by aerobic soil conditions (Arao et al., 2009, Kawasaki et al., 2012). In contrast, arsenic (As), another PTE was found to be easily accumulated in flooded rice (Marin et al., 1993). While aerobic soil condition inhibited As translocation from soil to plant (Talukder et al., 2012).
Despite availability of volumetric information regarding response of Cd, As, Zn, etc. to different water regimes, little is known about effect of water management on Mn, Ni, Cu, Co and Mo accumulation in milled rice. It is imperative to initiate studies on such global issue in the scenario of reducing PTEs accumulation in food-chain. Therefore, present study was designed in Central China for comparative assessment of different planting patterns and cultivars regarding PTEs (Mn, Co, Ni, Cu, Zn, Cd, Mo, As) concentration in milled rice and milled rice yield under field conditions.
Section snippets
Site description
Present study was conducted at Zhougan Village (29°51′ N, 115°33′ E), Dajin Town, Wuxue County, Hubei Province, China during 2012 and 2013 growing seasons. Prior to any field operation, soil samples were collected at the depth of 20 cm for analysis of soil physico-chemical properties and PETs concentration (Table 1). The soil of the experimental site was a silt loam with proportion of sand, silt and clay as 26, 64 and 10%, respectively.
Experimentation
The experiment was arranged in a randomized complete block
PTEs concentration in the soil at the experimental field
Data regarding chemical properties and total PTEs concentration in the soil are presented in Table 1. The PTEs concentration in the soil showed a trend of Mn > Zn > Ni > Cu > Co > As > Cd > Mo. Among them, Mn had the highest concentration (285.5 mg kg−1) followed by Zn (50 mg kg−1). Cd and Mo were the two elements with the lowest concentration (<1 mg kg−1) in the soil. Total Co, Ni and Cu were about 20 mg kg−1, whereas, As concentration was 5.3 mg kg−1. None of the PTEs in the experimental site exceeded the critical
Effect of PTEs concentration in the soil on PTEs concentration in milled rice
Present study demonstrated significant variations regarding PTEs concentration in milled rice among planting patterns and cultivars. Among PTEs accumulation, a wide range from <40 μg/kg for Co to >25,000 μg/kg for Zn & Mn was observed. Concentration of a PTE in the milled rice is governed by its concentration and bioavailability in the soil, therefore, the elements which were of a high concentration in soil also accumulated a large amount in rice, as the mobility and bioavailability of the PTEs
Conclusion
Along with the benefits of higher resource use efficiency and less labor requirement; comparable milled rice yield with TFR and moderate PTEs accumulation suggested that DSF is more suitable planting pattern in the context of environmental sustainability. With a short flooding periods, DSF reduced the As and Mo concentration in milled rice, compared with TFR, and decreased the Zn, Mn, Ni, Cu, Cd and Co concentration in milled rice as compared to DSA, especially for As and Cd. Furthermore,
Acknowledgements
This work is supported by the National Natural Science Foundation of China (Project No. 31371571), the Open Project Program of Key Laboratory of Crop Ecophysiology and Farming System, Ministry of Agriculture (Project No. 201301), the National Science & Technology Pillar Program (2013BAD20B06), and the Fundamental Research Funds for the Central Universities (Project No. 2013PY109).
References (47)
- et al.
Exposure to metal mixtures and human health impacts in a contaminated area in Nanning, China
Environ. Int.
(2005) - et al.
High levels of heavy metals in rice (Oryza sativa L.) from a typical E-waste recycling area in southeast China and its potential risk to human health
Chemosphere
(2008) - et al.
Risk assessment of potentially toxic element pollution in soils and rice (Oryza sativa L.) in a typical area of the Yangtze River Delta
Environ. Pollut.
(2009) - et al.
Biogeochemistry of paddy soils
Geoderma
(2010) - et al.
Uptake and translocation of Cd in different rice cultivars and the relation with Cd accumulation in rice grain,”
J. Hazard. Mater.
(2007) - et al.
Rice is a major exposure route for arsenic in Chakdaha block, Nadia district, West Bengal, India: a probabilistic risk assessment
Appl. Geochem.
(2008) - et al.
Effect of cadmium on lipid peroxidation, superoxide anion generation and activities of antioxidant enzymes in growing rice seedlings
Plant Sci.
(2001) - et al.
Effect of water management, arsenic and phosphorus level son rice in a high-arsenic soil–water system: II. Arsenic uptake
Ecotoxicol. Environ. Saf.
(2012) - et al.
Rice as the most influential source of cadmium intake among general Japanese population
Sci. Total Environ.
(2003) - et al.
The contamination and transfer of potentially toxic elements and their relations with iron, vanadium and titanium in the soil–rice system from Suzhou region, China
Environ. Earth Sci.
(2013)
Heavy metal dispersion, persistence, and bioaccumulation around an ancient copper mine situated in Anglesey, UK
Ecotoxicol. Environ. Saf.
Heavy metal contaminations in a soil–rice system: identification of spatial dependence in relation to soil properties of paddy fields
J. Hazard. Mater.
Soil factors associated with zinc deficiency in crops and humans
Environ. Geochem. Health
Genotypic differences in cadmium concentration and distribution of soybeans and rice
Japan Agric. Res. Q.
Effects of water management on cadmium and arsenic accumulation and dimethylarsinic acid concentrations in Japanese rice
Environ. Sci. Technol.
Reduction of cadmium translocation from roots to shoots in eggplant (Solanum melongena) by grafting onto Solanum torvum rootstock
Soil Sci. Plant Nutr.
Grain position affects grain macronutrient and micronutrient concentrations in wheat
Crop Sci.
Improving zinc bioavailability in transition from flooded to aerobic rice. A review
Agron. Sustain. Dev.
Solubilização dos fosfatos naturais Patos de Minas e Arad em dois solos alagados
Rev. Bras. Ciênc. Solo.
Genotypic variation in grain cadmium concentration of lowland rice
J. Plant Nutr. Soil Sci.
New characteristics of rice production and quality improvement in China
Rev. China Agr. Sci. Technol.
Behavior of contaminant heavy metals in soil–plant system
Comparative study on soil pollution with toxic substances on farmlands close to old and New Industrial sites in Ethiopia
Bull. Chem. Soc. Ethiop.
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