Determination of the total chromium in vegetable, rice samples cultivated and marketed along Nhue River

Rice and vegetables are daily used as food served as integral parts of a meal. So vegetables and rice constitute an important part of the human diet [1]. In vegetables and rice there are carbohydrates, proteins, as well as vitamins and minerals [1]. Vegetables can absorb metals from soil, water as well as from waste deposits on the parts of the vegetables exposed to the air from polluted environments [2]. As human activities are increasing, especially combining with the application of modern technologies and fertilizers, the pollution and contamination of the human food chain has become inevitable [3]. Besides, the number of elements, such as chromium (Cr), lead (Pb), cadmium (Cd), nickel (Ni), cobalt (Co), copper (Cu)...in the high levels can be harmful to plants [4]. The heavy metals in the small concentrations from environment can be accumulated in foods (rice and vegetables). Heavy metals are one of a range of important types of contaminants that can be found on the surface and in the tissue of vegetables. For chromium, there are two common oxidation states present in environments such as Cr(III) and Cr(VI). The form of Cr(III) is considered to be the trace element essential for proper functioning of living organisms [5].The chromium state of Cr(VI) was reported to exert toxic effect on biological systems. Besides, Cr(VI) ions are the most mobile in environment of water and soil that are more available for living plants. Plants grow in the Cr(VI) contaminated environment often show an accumulation particularly in root tissue [5]. The mechanisms involved in the uptake and translocation of chromium in the plants is not understood at all. Because there is uncertainty about the ionic species present in different systems. There is however evidence that Cr(VI) is reduced to Cr(III) at the plant root surface and the irrespective of the chromium is retained in the roots [6,7]. This element, at the concentrations exceeding the physiological demand of vegetables, not only could cause toxic effect on them but also could enter food chains, get biomagnified and pose a potential threat to human health [8,9]. At present, the problem of contamination food and clean, safe food are of great interest [10]. In this article the presence of chromium in rice and vegetable samples were analyzed. All samples were collected along Nhue river. The water of Nhue river is used to watering vegetables and rice. The water from Nhue River was identified as a water resource contaminated by heavy metals [11]. The total chromium in the water spinach samples present in the roof and fresh stem part was analyzed. The presence of chromium in the rice and vegetable (water spinach) could allow an assessment of the safety levels of food (rice and vegetables) cultivated and marketed along Nhue River.