Journal Article
Heavy Metal Contamination in Oryza sativa L. at the Eastern Region of Malaysia and Its Risk Assessment
Nur Syahirah Zulkafflee•2022
Nurul Adillah Mohd RedzuanSara Nematbakhsh
Top 14% · 86th Percentile
48 citations · Pollution
Open Access

TLDR

Rice grown in the studied parts of Kelantan contained several harmful substances. Eating it could raise both long-term illness and cancer risks, especially for children.

Summary

1 Study Aim

The study aimed to measure five heavy metals (persistent chemical elements that can harm living things) in rice plants from Kelantan, Malaysia. The authors examined lead, cadmium, copper, chromium, and arsenic. They also assessed how these substances move through rice plants and estimated health risks from eating the rice. The research asked whether rice grown in these areas could expose people to harmful levels of contamination.

2 Study Design

The authors sampled mature MR220 CL2 rice, soil, roots, stems, leaves, and grains from Kota Bharu, Pasir Mas, and Pasir Puteh. Each area had three plots, with triplicate samples collected in October 2018. The team measured metals using inductively coupled plasma mass spectrometry (ICP-MS), a highly sensitive chemical testing method. Enrichment factors measured soil-to-grain transfer, while translocation factors measured movement within plants. The health risk assessment followed United States Environmental Protection Agency (USEPA) guidelines for adults and children. Statistical comparisons and principal component analysis (PCA), a method for finding patterns in complex data, supported interpretation. The researchers tested rice, soil, and plant parts from nine plots using laboratory measurements and exposure estimates.

3 Findings

The authors found arsenic was the most concentrated metal in soil. All measured soil and plant concentrations were below the cited standards, but arsenic and chromium accumulated in grains. Enrichment factors remained below one, with copper highest, followed by arsenic, chromium, cadmium, and lead. Chromium and lead moved most efficiently from stems into grains. The hazard quotient (HQ), an indicator for one substance’s non-cancer risk, exceeded one for arsenic. The combined hazard index (HI), which adds risks from several substances, exceeded one for both groups. Lifetime cancer risk (LCR) from arsenic and total cancer risk (CRt) exceeded accepted limits, especially for children. The authors recommend monitoring soils, testing market rice, and reducing contamination from farm chemicals. Regularly eating this rice could harm health, so stronger checks and safer farming practices are needed.

Abstract

Paddy plants tend to accumulate heavy metals from both natural and anthropogenic sources, and this poses adverse risks to human health. The objective of this study was to investigate heavy metal contamination in paddy plants in Kelantan, Malaysia, and its health risk assessment. The bioaccumulation of heavy metals was studied by means of enrichment (EF) and translocation factors (TF). The health risk assessment was performed based on USEPA guidelines. The EF for heavy metals in the studied areas was in the descending order of Cu > As > Cr > Cd > Pb. Meanwhile, Cr and Pb exhibited higher TF values from stem to grain compared with the others. The combined hazard index (HI) resulting from five heavy metals exceeded the acceptable limit (HI >1). The lifetime cancer risk, in both adult and children, was beyond the acceptable limit (10−4) and mainly resulted from exposure. The total cancer risk (CRt) due to simultaneous exposures to multiple carcinogenic elements also exceeded 10−4. In conclusion, intake of heavy metal through rice ingestion is likely to cause both non-carcinogenic and carcinogenic health risks. Further research is required to investigate the extent of heavy metal contamination in agricultural soils and, moreover, to establish human exposure as a result of rice consumption.