Seasonal Variation in Heavy Metal Accumulation and Associated Health-risks From the Consumption of Ww-irrigated Amaranthus in the Zagyuri Community Tamale, Ghana

The reuse of Wastewater (WW) for vegetable cultivation increases public health risks (HR) due to heavy metal (HM) contamination. The study aimed at investigating the effects of seasonal variation in HM and its HR on the consumption of WW-irrigated amaranthus in Tamale. The study employed eight different irrigation sources in a Randomized Complete Block Design with three replications. Physiochemical properties of biochar, soil, and water were studied, and HM analysed with an Absorption Spectrophotometer (Model 2380, Perkin Elmer, Inc., Norwalk, CT, USA). Variation among filtrate was determined using GenStat-Release 8.1 statistical package and means by Standard Error of the Difference (SED 5%). The Bioconcentration factors (BF) and HR assessments were conducted using estimated daily intake, hazard quotient (HQ), and hazard index models for adults and children. The HM ranges from 0.04 - 668.76 mg/kg from the soil and 0.01 - 2.05 mg /l in irrigated-water. Rice-Husk-Biochar-400oCfiltrate showed 99.85 % removal for (Fe); RHB600 oC (97.46%) for Mn and 99.58 % Cd (GHB 600 OC) in WW. Only %WW had a BF value of Cr (7.5000) in the dry season. Iron Fe (5.4880), Cd (5.0) and Mn (2.225) posing the greatest HR for adults and Mn (1.0953); Fe (2.7014) for children. Seasonal WW irrigation results in variable metal uptake by Amaranthus cruentus, exposing consumers, especially children, to significant HR.