Heavy Metals in Cereals and Pulses: Health Implications in Bangladesh

Overview

Islam, Ahmed, and Habibullah-Al-Mamun measured chromium, nickel, copper, zinc, arsenic, cadmium, and lead in five commonly consumed cereals and pulses from agricultural fields in Bogra district, Bangladesh. The food panel covered rice, wheat, maize, lentil, and black gram, with paired soil sampling used to discuss soil-to-crop transfer. The occurrence data report total/unspecified arsenic as As; the paper’s carcinogenic-risk model assumes 90% inorganic arsenic in cereals and pulses, but it does not measure arsenic speciation in the food samples.

Key numbers

Table 3 reports concentrations in mg/kg for cereals and pulses collected from agricultural fields of Bogra district, Bangladesh:

The Results text summarizes that average heavy-metal concentrations across food groups followed maize > black gram > lentil > wheat > rice. It highlights black gram chromium (Cr) at 2.4 mg/kg, maize Zn at 3.6 mg/kg with range 1.5-7.3 mg/kg, rice As at 0.47 mg/kg, and wheat cadmium (Cd) at 0.16 mg/kg with range 0.001-0.66 mg/kg.

Table 4 reports estimated daily intake (EDI) in mg/day; total intake from the five foods was Cr 0.95, nickel (Ni) 0.57, Cu 0.95, Zn 1.2, arsenic (As) 0.26, Cd 0.028, and lead (Pb) 0.35. Rice contributed the largest daily intake because the source used a rice consumption rate of 445 g/person/day. Table 5 reports exposure-context metrics: total target hazard quotient through rice was 14; the hazard index for all five foodstuffs was 17; total carcinogenic risk was As 5.8 x 10-3 and Pb 4.9 x 10-5.

Methods (brief)

The study collected rice, wheat, maize, lentil, and black gram from an urban area in northern Bangladesh. Wheat, maize, and pulses were collected during February-March 2012; rice was collected during August-September 2013. The authors prepared composite samples for each food item at each sampling site, dried food samples at 105 °C for 24 h, and analyzed microwave-digested samples by ICP-MS. Soil from the same fields was also sampled to estimate transfer factors, but soil concentrations are exposure-context information rather than product occurrence values.

Implications

This source supplies Bangladesh field-crop occurrence evidence for total/unspecified arsenic, cadmium, lead, chromium, nickel, copper, and zinc in rice, non-rice cereals, and pulses. It is most directly relevant to rice-bulk-grain routing because rice has the largest sample count and dietary-intake contribution in the paper, but the same table also supports non-rice grain and legume/pulse routing. Downstream synthesis should keep measured total arsenic distinct from the paper’s modeled 90% inorganic-arsenic assumption and should not treat total chromium as Cr(VI).

Update history

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