Accumulation of metals and metalloids in turnip (Brassica rapa L.) irrigated with domestic wastewater in the peri-urban areas of khushab city,Pakistan

Accumulation of different metals and metalloids was assessed in a potential vegetable crop,turnip (brassica rapa l.) irrigated with domestic wastewater in the peri-urban areas of khushab city,pakistan. two sites at a distance of 15 km radius were selected for this study. the levels of different metals and metalloids such as cr,mn,fe,co,ni,cu,zn,as,se,mo,cd and pb,at site-i were 0.06,15.8,34.4,13.5,1.95,3.15,4.25,41.5,1.68,4.79,8.76,and 27.5 mg kg-1,whereas those at site-ii were 0.07,23.7,41.9,20.2,3.70,3.63,9.64,47.08,2.73,5.85,19.09 and 33.85 mg kg-1,respectively. in general,the metal and metalloid concentrations were higher at site-ii than those found at site-i,except cd. the concentrations (mg kg-1) of metals and metalloids in the vegetable at site-i following the order of arrangement in the case of soil were,9.07,33.66,28.48,0.49,7.64,18.73,35.79,2.53,0.41,6.8,0.58 and 7.28 mg/kg,whereas those at site-ii were 17.09,49.23,42.05,0.77,9.95,15.10,55.5,5.21,0.63,16.1,0.66 and 12.6 mg/kg,respectively. at both sites the levels of metals in the vegetable were below the permissible level except those of mn,ni,zn,mo and pb. at both sites,the transfer factor ranged from 0.03-216.3 mg kg-1 with cr having the highest transfer factor. the metal pollution index in soil was in the following order: cd > ni > se > zn > mn > co > cr > pb > mo > fe > cu > as and in the vegetables as mo > as > cr > pb > zn > co > se > fe > mn > ni > cd > cu,respectively.