Assessing selected heavy metals in vegetables and soils irrigated with wastewater at Haripur, Pakistan

摘要

A study was carried out to compare the impact of wastewater irrigation on the concentrations of Pb and Cd among brassica, spinach, radish and coriander in Haripur area of Pakistan. Results showed that wastewater contained higher amount of these metals. Similarly vegetables irrigated with wastewater exhibited higher concentration of metals. The amount of metals remained highly dependent on the kind of vegetable and its associated field. Higher Pb concentration in wastewater enhanced its level in both soil and plant of the respective field as compared to Cd. Water soluble Pb (mg kg(-1)) in soils differed with the kind of cultivated vegetable in the order of brassica (8.6) > spinach (6.3) > coriander (4.4) > radish (2.3). The Pb values in soils were within the acceptable limits. Water soluble Cd (mg kg(-1)) in soil exceeded permissible level among fields: brassica (0.9) > Spinach (0.8) > coriander (0.7) > radish (0.6) fields, respectively. The concentrations of ABDTPA extractable Pb were found in the order of radish cultivated soil (8 mg kg(-1)), coriander soil (13.9 mg kg(-1)), spinach soil (15.9 mg kg(-1)) and brassica soil (17.3 mg kg(-1)). The average concentrations of ABDTPA Cd among soils were found statistically similar. Both ABDTPA extractable metals exceeded the prescribed limits. Among vegetables, brassica got the highest Pb concentration (128.2 mg kg(-1)), followed by spinach (107.3 mg kg(-1)), coriander (98.7 mg kg(-1)) and radish (103.2 mg kg(-1)), respectively. The mean concentrations of Cd were noted as 20.9 mg kg(-1) in coriander, 16.3 mg kg(-1) in brassica, 15.5 mg kg(-1) in spinach and 12.4 mg kg(-1) in radish. Both metals in vegetables exceeded the maximum permissible limits of WHO. This study apparently concludes that irrigation of wastewater may carefully be rationalized especially for vegetable crops and wastewater before its application to vegetables, must be investigated.