POLLUTION INDICES AND HEALTH RISK ASSESSMENT OF HEAVY METALS IN RICE FROM GASHUA, YOBE STATE.

Abstract

Heavy metal contamination in food crops, particularly rice, poses significant health risks due to widespread consumption. Gashua, Yobe State, Nigeria, is a key agricultural area where rice cultivation may be influenced by environmental pollution. However, few studies have quantified the health risks of heavy metal contamination in this region and link it to the prevalence of Kidney diseases within the study area. This study addresses these challenges by assessing the levels of Arsenic, Cadmium, Lead, and Chromium in rice and evaluating associated health risks. A simple random sampling technique was used to collect the rice samples. A total of 120 rice samples were collected, 90 paddy rice from four farms and 30 parboiled rice from Gashua Market. The samples were digested and analyzed using Micro plasma atomic emission spectrometry (MP-AES). The data generated was subjected to a one-way analysis of variance. The result of the study revealed a significant (P<0.05) difference in heavy metals concentration across all samples. Parboiled Samples from Gashua market exhibited the highest Arsenic concentration at (0.383mg/kg) greatly surpassing WHO/USEPA acceptable limits. Cadmium (0.0242mg/kg) also exceeded the permissible limit of 0.001mg/kg. Lead concentration from all locations superseded the recommended limit especially from Gashua market at 0.102mg/kg exceeding the limit of 0.0035mg/kg. Hazard quotient (HQ) values indicated children are at low risk at location Gashua South (GS) 0.8266 thou not exceeding the threshold of 1, Gashua Market 0.5984, and Gashua North 0.5398 were all below the threshold of 1 however in adults, the value of Chromium at Gashua Market (2.162) was above the threshold and poses a significant health risk. The hazard index (HI) for both adults and children were greater than one 1 mainly contributed because of the high concentration of As in GMK (0.5984), As in GS (0.8266), and Cr in GMK (2.162) which also signifies potential health risk. The Incremental lifetime cancer risk (ILCR) showed a heightened risk of cancer from long-term exposure. In conclusion, rice grown and sold in Gashua poses potential health risks due to heavy metal contamination. Continuous monitoring by regulators (NAFDAC), in-depth research, public health interventions, and stricter regulatory enforcement are necessary to mitigate these risks.