Arsenic accumulation in lentil (Lens culinaris) genotypes and risk associated with the consumption of grains

Overview

Alam and colleagues measured total arsenic uptake from arsenic-treated peat moss into lentil roots, shoots, pods, and grains. The study is a controlled greenhouse soil-to-crop transfer experiment rather than a market occurrence survey. The routeable food values are the total arsenic values reported for lentil grains at weeks 10 and 13.

Key numbers

The experimental treatments were control (0 added arsenic), A3 = 3.0 mg As kg−1 peat moss, and A6 = 6.0 mg As kg−1 peat moss. Three varieties (pardina, red chief, and precoz) were grown with three replications at week 6, 10, and 13, giving a total of 81 pots.

Table 3 reports arsenic accumulation in mg kg−1 in root, shoot, and grain:

The Results text states that grain arsenic was lower than root and shoot arsenic during weeks 10 and 13. It also states that arsenic in grains increased by 20% and 40% in red chief and precoz with 6 mg As kg−1 peat moss compared with 3 mg As kg−1 peat moss after week 13, and that arsenic in grain was 17% higher under 6 mg As kg−1 peat moss compared with 3 mg As kg−1 peat moss after week 13.

Method detection limit for total arsenic was 0.02 µg/l or ppb (parts per billion).

Methods (brief)

The pot experiment used arsenic-free peat moss as the growing medium and sodium arsenate dibasic heptahydrate as the arsenic source. Lentil seeds were sown in pots on 13th March, 2014; after emergence, 5 seedlings were kept per pot. Root, shoot, pod, and grain samples were collected at weeks 6, 10, and 13, dried for 72 hours at 55-65 °C, ground with liquid nitrogen, and sieved through 250 µ mesh. Root, shoot, and grain samples were digested with concentrated nitric acid and perchloric acid. Total arsenic was measured by flow-injection hydride-generation atomic absorption spectrophotometry (FI-HG-AAS, Perkin Elmer A Analyst 400-USA), with three replicate measurements per digested sample and NIST SRM checks.

Implications

This source provides experimental soil-to-lentil transfer evidence for total arsenic in edible lentil grains. It supports legume/pulse routing as supply-chain evidence, but it should not be treated as a market distribution for lentil products because arsenic treatments were deliberately imposed in a controlled pot study. No inorganic arsenic speciation was measured, so the grain values remain total arsenic.

Update history

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