Arsenic is ubiquitous in nature appearing in various chemical forms.

Samples of soil, the broad bean plant, Vicia faba and irrigation water were collected from the same agricultural site in Dokan, in the Kurdistan region of Iraq. Total arsenic and arsenic speciation were determined in all materials by ICP-MS and HPLC-ICP-MS, respectively. Available arsenic (11%) was also determined within the soil, together with Cd, Cr, Cu, Ni, Zn, Fe and Mn. The concentrations of total arsenic were: soil (5.32μgg(-1)), irrigation water (1.06μgL(-1)), roots (2.065μgg(-1)) and bean (0.133μgg(-1)). Stems, leaves and pods were also measured. Inorganic As(V) dominated soil (90%) and root (78%) samples. However, organo-arsenic (MMA, 48% and DMA, 19%) was the more dominant species in the edible bean. The study provides an insight into the uptake, preferred disposal route, speciation changes and loss mechanism involved for arsenic with this food source.

Enzymatic extraction methods were evaluated with classical extraction approaches for the determination of arsenic in food. The extraction efficiency for total arsenic was determined by analysing CRM materials DORM-3 fish protein, NIES 106 rice flour and GBW10015 spinach. These were compared with total arsenic concentration determined using microwave-assisted acid digestion and ICP-MS. The total arsenic concentrations in the CRM materials were in good agreement with the certified values. Enzymatic hydrolysis using trypsin has been successfully employed to extract arsenic species in DORM-3 and fish samples. Whilst this method of hydrolysing the proteins worked well for the fish samples, an alternative approach was required to facilitate the digestion of cellulose in plant materials. However, enzymatic extraction using cellulase was found to give unsatisfactory results for both the NIES and GBW10015 CRM materials. Dilute nitric acid (1% HNO3) was found to give a more efficient extraction for arsenic species in the same CRM materials and rice samples. The study was extended to evaluate a range of real samples. Total arsenic concentrations in 13 different types of fish tissue were determined following microwave-assisted acid digestion using nitric acid/hydrogen peroxide, followed by measurement using HPLC-ICP-MS for speciation analysis. The results obtained for fish were in the range of 3.53-98.80 µg g(-1) As (dry weight). Similarly, the results of 17 rice samples were in the range of 0.054-0.823 µg g(-1). This study demonstrates the importance of selecting an appropriate extraction technique for the quantitative measurement of arsenic species in food.

The transport of arsenic from soil through to edible crop is important when assessing the potential health risks from a food source. Samples of soil, irrigation water and the rice...

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Heavy metal concentrations were determined in indigenous vegetables collected in Erbil city-Kurdistan region of Iraq. ICP-MS was applied to determine total concentrations of Al, Co, Fe, Mn, Ni, Se and Zn in Malva parviflora, Gundelia tournefortii, Arum spp, Spinacia oleracea,  Mentha longifolia, Beta vulgaris subsp, Apium graveolens, Lepidium sativum L, Allium Kurrat. Schweinf and Allium fistulosum   after acid digestion of the samples with the aid of  microwave using nitric acid/ hydrogen peroxide. The contents of heavy metals in vegetable samples varied between 40-451 for Al, 0.04-0.96 for Co, 53-247 for Fe, 3.37-11.58 for Mn, 0.26-5.53 for Ni, 0.09-0.98 for Se and 1.58-4.41 for Zn on the basis of dry weight. The methodology was validated by certified reference material (CRM) GBW10015-spinach and inductively coupled plasma mass spectrometry analysis.  The levels of Al, Mn and Ni in some investigated vegetables are higher than the permissible limits for human consumption.