A potential toxicological risk assessment of heavy metals and pesticides in irrigated rice cultivars near industrial areas of Dhaka, Bangladesh

Overview

Huda et al. (2024) measured metal and pesticide residues in a soil-water-rice system near Gazipur, Bangladesh, where three rice fields were irrigated with water sources influenced by nearby industrial activity. The routeable product occurrence data are the rice-grain concentrations in Table 3; soil, irrigation water, husk, and stem values are supply-chain context and should not be pooled as finished-grain values. Arsenic and mercury are reported only as total/unspecified arsenic (As) and mercury (Hg), so this page records them as total arsenic (tAs) and total mercury (tHg), not inorganic arsenic or methylmercury.

Key numbers

Table 3 reports rice-grain concentrations in µg/kg. The plant-part basis is not explicitly labelled as wet or dry weight in the table; the Methods section describes acid digestion of separated grain, husk, and stem components, with husks and stems air-dried before grinding.

The highest rice-grain values in Table 3 were nickel (Ni) 5.53 x 10^4 µg/kg in Field-III, Zn 7.51 x 10^3 µg/kg in Field-III, Mn 4.20 x 10^3 µg/kg in Field-II, lead (Pb) 3.16 x 10^3 µg/kg in Field-I, chromium (Cr) 7.88 x 10^2 µg/kg in Field-III, Cu 5.92 x 10^2 µg/kg in Field-I, cadmium (Cd) 2.49 x 10^1 µg/kg in Field-III, tAs 2.16 x 10^1 µg/kg in Field-I, and tHg 6.40 x 10^1 µg/kg in Field-III.

Table 3 places Field III husk lead near 5.96e3 µg/kg (5.96 x 10^3 µg/kg, 5966.54 µg/kg) and Field III stem lead near 4.97e2 µg/kg (4.97 x 10^2 µg/kg, 497.93 µg/kg). The narrative on page 7 swaps those two labels. This page follows Table 3.

Supply-chain context from Table 2, not finished-grain occurrence: irrigation-water Pb was 1.03 x 10^3 µg/L in Field-I, 7.68 x 10^2 µg/L in Field-II, and 7.43 x 10^2 µg/L in Field-III; irrigation-water Cd was 1.02 x 10^2, 9.29 x 10^1, and 5.85 x 10^1 µg/L, respectively. Soil Pb was 5.91 x 10^4, 6.95 x 10^4, and 6.65 x 10^2 µg/kg across Fields I-III, respectively.

Table 4 reports pesticide co-contaminants in µg/g: diazinon in rice grain was 0.56 +/- 0.23 in Field-I, 0.94 +/- 0.20 in Field-II, and 1.68 +/- 0.089 in Field-III; fenitrothion in rice grain was BDL in Field-I, 0.45 +/- 0.079 in Field-II, and BDL in Field-III. These pesticide values are not metals and are not listed in source metadata metals.

Methods (brief)

The study used systematic random sampling across three fields near Gazipur, Bangladesh. Soil, irrigation water, and whole rice plants were collected in July 2023; grain was separated from straw in the laboratory, and husk was separated from grain with a mortar and pestle. Plant components were digested with nitric acid and perchloric acid, then analyzed by ICP-MS using a PerkinElmer NexION 2000 system. The metal panel included As, Se, Pb, Be, Cd, Co, Cr, Cu, Mn, Ni, Zn, V, Fe, and Hg. Diazinon and fenitrothion residues were analyzed by HPLC/UV after hexane/water extraction.

Implications

This source supports a local, industrial-area rice occurrence route for harvested grain in Bangladesh, with paired soil and irrigation-water context that helps explain the contamination pathway. It should not be treated as a general Bangladesh retail-rice baseline because the sampling frame is three specific fields near industrial activity. The page preserves source-reported tAs and tHg without substituting inorganic arsenic or methylmercury.

Related evidence

• Rice
• Rice (white, brown, wild — bulk grain)
• Arsenic, Total
• Lead
• Cadmium
• Chromium
• Mercury
• Nickel

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git.