Health Risk Assessment of Some Heavy Metals In Irrigated Brassica Oleracea L.and Lactuca Sativa Vegetables of Barkin-Ladi Lga of Plateau State, Nigeria

Abstract

The objectives of the present study were to investigate heavy metal (Cd, Cr, Mn and Pb) accumulation in Cabbage (Brassica oleracea L.) and Lettuce (Lactuca sativa) vegetable samples, which were freshly harvested within 7 different vegetable farm location grown around Barkin Ladi LGA of Plateau State, Nigeria. Heavy Metals concentrations in the vegetable samples were analyzed using Atomic Absorption Spectrophotometer (Bulk Scientific Model 210 VGP). Concentration of Chromium in Cabbage ranged from0.32mg/kg - 0.05mg/kg and Lettuce was between 0.23mg/kg-0.04mg/kg. Cadmium level of vegetables from the analysis of Cabbage ranged between 0.65mg/kg - 0.15mg/kg, and Lettuce was between 0.60mg/kg-0.13mg/kg. Mn level of vegetables from the analysis of Cabbage ranged between 0.37mg/kg-0.04mg/kg and the range for Lettuce was between 0.45mg/kg-0.10mg/kg. Pb level of vegetables from these the analysis of Cabbage ranged between 0.35mg/kg-0.08mg/kg and the range for Lettuce was between 0.51mg/kg-0.05mg/kg. The calculated mean and standard deviation for Cabbage sample for Cd, Cr, Mn and Pb were 0.353±0.162, 0.144±0.066, 0.165±0.087 and 0.156±0.075 respectively, while Lettuce samples were 0,327±0.140, 0.119±0.062, 0.258±0.095 and 0.2300.122 respectively. In general, the concentration trends of heavy metal investigated were on the order Cd ? Mn ? Pb ? Cr in all the sample matrices of both vegetables. Risk analysis parameters for both sample matrices computed using standard methods for both adult and children were HRI, HQ, DIM, EDIM, MPI. Different methods of health risk assessment of the heavy metals concentration also revealed although the vegetable may be safe for consumption, bioaccumulation risk index showed that there could be potential danger of consumption over a long period of time. This study concludes that different vegetables accumulate and translocate variable amount of heavy metals from the soil into their tissues. Hence, it is not advisable to consume vegetable samples collected from this site based on the permissible limits as recommended by World Health Organization (WHO).