ESTIMATION OF CONCENTRATION OF HEAVY METALS IN TURNIP PLANT (BRASSICA RAPA)

Abstract

Agricultural soils contaminated with heavy metal has emerged as an undetectable threat to food safety and human well-being everywhere in the world. Turnip (Brassica rapa) is particularly vulnerable to the adverse impact of global warming due to its high bioaccumulation property of toxic metals such as cadmium, lead, chromium, arsenic and nickel. With at least small amounts of soil contamination, these contaminants can be transferred to the human food chain. Despite increased research on the estimation of heavy metal in turnip, there are still significant inconsistencies in sample preparation and digestion processes, and analysis methods, which continue to cause wide variation in reported concentrations and inconclusive conclusions on health hazards. This review technically summarizes information on how heavy metal concentrations in turnip can be estimated between 2010 and 2025. The general aims were to critically evaluate the current methodologies of analytical techniques like wet digestion, microwave assisted digestion, flame atomic absorption spectroscopy, graphite furnace AAS, and inductively coupled plasma mass spectrometry, to synthesize world data on metal accumulation patterns and health risks associated with them. The major results were that cadmium and lead are often found in excess of, and even exceeding, the permissible limits of the FAO WHO in turnips cultivated near industrial areas, urban farmland and wastewater irrigated lands. Microwave assisted digestion in combinations with ICP MS or GFAAS had the highest recovery rates of better than 92 percent and lowest limits of detection of microgram per kilogram. The variations in translocation factors between soil of various pH and organic matter content had significant variability with the accumulation of two to five times more metal on the turnip leaves than on the storage roots. Assessment of health risk through target hazard quotient showed that children are more at risk than the adults with chronic daily intake of lead and cadmium due to consumption of turnip being a potential non carcinogenic risk in the contaminated areas. The review finds that harmonized standard operating procedures of sample preparation, constant use of certified reference material and region-specific risk assessment framework are urgently needed to be able to rely on the use of heavy metal in the monitoring of turnip as a food safety regulation