Arsenic in rice agrosystems (water, soil and rice plants) in Guayas and Los Ríos provinces, Ecuador

Abstract

Geogenic arsenic (As) can accumulate and reach high concentrations in rice grains, thus representing a potential threat to human health. Ecuador is one of the main consumers of rice in South America. However, there is no information available about the concentrations of As in rice agrosystems, although some water bodies are known to contain high levels of the element. We carried out extensive sampling of water, soil, rice plants and commercial rice (obtained from local markets). Water samples were analysed to determine physico-chemical properties and concentrations of dissolved arsenic. Soil samples were analysed to determine total organic C, texture, total Fe and amorphous Fe oxyhydroxides (Fe), total arsenic (tAs) and the bioavailable fraction (As). The different plant parts were analysed separately to determine total (tAs), inorganic (iAs) and organic arsenic (oAs). Low concentrations of arsenic were found in samples of water (generally <10μgl) and soil (4.48±3mgkg). The tAs in the rice grains was within the usual range (0.042-0.125mgkg dry weight, d.w.) and was significantly lower than in leaves (0.123-0.286mgkg d.w.) and stems (0.091-0.201mgkg d.w.). The Fe and tAs and also As in flood water were negatively correlated with tAs in the plants. However, the concentrations of As in stems and leaves were linearly correlated with tAs in the soil and flood water. The relationship between tAs and arsenic in the grain fitted a logarithmic function, as did that between tAs in the grain and the stem. The findings seem to indicate that high concentrations of arsenic in the environment (soil or water) or in the rice stem do not necessarily imply accumulation of the element in the grain. The iAs form was dominant (>80%) in all parts of the rice plants.

Effect of phosphorus on arsenic uptake and metabolism in rice cultivars differing in phosphorus use efficiency and response

“…Significant differences in nutrient concentrations among different cultivars could be the result of differences in the removal of As from the system among these genotypes, as well as development of As tolerance and adaptations to other stressful conditions (Tu and Ma 2003, Panda et al 2010, Zheng et al 2013, Otero et al 2016.…”

“…Rice, an important staple food, is considered to be a major source of As in the human diet (Mondal and Polya 2008, Liang et al 2010, Carey et al 2015, Otero et al 2016. There is therefore an urgent need to develop mitigation measures to reduce As concentrations in rice.…”

Risk analysis as a strategic sphere in providing food products safety

“…1. Глобальные вызовы, формирующие риски для здоровья потребителей присутствия в пищевом сырье и/или продуктах питания биологических агентов и токсичных химических элементов в концентрациях, превышающих нормативы безопасности [1][2][3][4][5][6]. Биологические, химические, радиационные факторы риска могут появляться в разных точках пищевой цепи.…”

Risk analysis as a strategic sphere in providing food products safety

“…The challenges are variable; they are caused by globalization, borders open for goods and services, an increased variety of technologies and raw materials applied in food products manufacturing, much greater volumes of uncontrollable or poorly controllable trade, first of all, electronic one, state surveillance becoming more democratized etc. (Figure 1 Control and surveillance activities performed by state authorities and scientific research accomplished in many countries allowed to detect biological agents and toxic chemical elements in food raw materials and/or food products; these hazardous substances occurred there in concentrations higher than those fixed in safety standards [1][2][3][4][5][6]. Biological, chemical, and radiation risk factors can occur in various sections in food chains.…”

“…As a result, more than half Russians who are older than 30 suffer from overweight and obesity and it can lead to cardiovascular diseases, malignant neoplasms, and pancreatic diabetes. In 2016 primary morbidity with obesity among adults older than 18 amounted to 285.85 per 100,000 adult people (it was 284.85 in 2015; 188.05 in 2014; 161.84 in 2013; 123.56 in 2012) 2 . Vitamins and microelements are not consumed in sufficient quantities in many Russian regions.…”