Levels and Health Risk Assessment of Selected Heavy Metals in Selected Packaged Culinary Herbs Consumed in Port Harcourt, Rivers State, Nigeria

Abstract

Culinary herbs are widely consumed in Port Harcourt, Nigeria, for flavoring and dietary enhancement. However, increasing environmental pollution from petroleum exploration, industrial emissions, and vehicular activities raises concerns about heavy metal contamination in food products. This research work was done to determine the levels of lead (Pb), cadmium (Cd), and arsenic (As) in eight selected packaged culinary herbs (bay leaves, thyme, rosemary, and basil) purchased from Choba market, Port Harcourt, and assesses the associated non-carcinogenic health risks for adults and children. These Samples were purchased from Everyday Supermarket and Choba Market at Choba, Port Harcourt, Rivers State and were acid-digested using aqua regia, and metal concentrations were quantified using Flame Atomic Absorption Spectrometry (FAAS) following the United States Environmental Protection Agency USEPA 7000B method. The analytical method demonstrated excellent linearity (R² Pb=0.9976, Cd=1.0000, As=0.9996). Lead was detected in four samples (50%) ranging from 0.0044–0.0068 mg/L (highest: Tiger Thyme, 0.0068 mg/L). Cadmium was detected in two samples (25%) at 0.0024 mg/L (Euroma Bay Leaves) and 0.0032 mg/L (Spice Supreme Rosemary) the highest. Arsenic was not detected. All concentrations were below World Health Organization limits (Pb: 0.012 mg/L; Cd: 0.004 mg/L). For Estimated Daily Intake of Lead in adults the Highest Concentration value in Tiger Thyme (0.0068 mg/L) was 0.0000011 mg/L/day and in child, the Estimated Daily Intake was 0.0000045 mg/L/day. The Highest Concentration value in Spice Supreme Rosemary (0.0032 mg/L) in Cadmium was 0.000021 and in child, the Estimated Daily Intake was 0.00000053 mg/L/day. Target Hazard Quotient values were <1 for all metals, for adults in Lead it was 0.000030 and for child it was 0.0011. For adult in Cadmium it was 0.0053 and for child, it was 0.021. The Hazard Index values were 0.0053 (adults) and 0.022 (children), indicating no significant non-carcinogenic risk under conventional assessment. While THQ/HI values suggest safety, detectable lead in 50% of samples remains a public health concern, particularly for children, as no safe lead exposure threshold exists. (World Health Organization, National Agency for Food and Drug Administration and Control)