Assessment of selected heavy metals accumulation in soil, water, and vegetables irrigated with domestic and industrial wastewater in Tabiya Adisalem, Adwa, Tigray, Ethiopia

Globally, there is growing concern about the health risks associated with consuming vegetables contaminated by heavy metals. This study assessed the concentrations of chromium (Cr), cadmium (Cd), and lead (Pb) in soil, water, lettuce, and cabbage from Tabia Adisalem, Adwa, Tigray, Ethiopia, using flame atomic absorption spectrometry. The area was selected due to irrigation practices that rely on water potentially contaminated by, domestic sewage from Adwa town and industrial discharges from Almeda textile PLC and Saba Dimensional stones PLC. Heavy metals were detected in the soil samples, with concentrations of Pb (0.117 ± 0.008 mg/kg), Cd (0.031 ± 0.003 mg/kg), and Cr (4.945 ± 0.010 mg/kg). In the water samples, the mean Pb level 0.298 ± 0.004 mg/L exceeded the USEPA irrigation guidelines of 0.015 mg/L, while Cr and Cd were below the detection limits. In cabbage, Pb and Cr concentrations were 0.242 ± 0.017 mg/kg and 2.231 ± 0.200 mg/kg, respectively. Lettuce samples contained Pb (0.166 ± 0.012 mg/kg) and Cr (1.099 ± 0.070 mg/kg), while Cd remained undetectable in both vegetables and water. The health risk index values for adults (0.174) and children (0.432) indicate minimal risk, as all detected metals were below the maximum tolerable daily intake. Thus, consumption of lettuce and cabbage from the area is considered safe. However, annual monitoring is recommended to track potential heavy metal accumulation in locally grown vegetables.