Present study identified metal accumulation potential, biochemical, growth, and human health risk attributes of wheat varieties (Zincol-16, NARC-09, NARC-11, Pakistan-13, Borlaug-16) cultivated in sewage sludge amended soils, that is, 80% soil + 20% sludge (C), 90% soil + 10% sludge (B) and 100% soil (control, A). Metal accumulation significantly varied (p < 0.05) among wheat varieties and the accretion pattern was roots > straw > grains. The Borlaug-16 was found most efficient for biochemical attributes, that is, proline (0.84), sugar (2.76) and total chlorophyll (2.35) in mg/g amongst selected varieties. Among treatments, maximum mean total chlorophyll (2.18), carotenoids (0.97), sugar (2.88) in mg/g, plant height (76.04 cm), weight per 1000 kernel (55 g) and spike length (4.17 cm) were recorded in B followed by A > C. However, mean membrane stability index%, that is, A (82.76)>B (75.26)>C (54.35) and mean proline contents, that is, C (0.49)>B (0.39)>A (0.29) in mg/g were recorded respectively. Mean hazard quotient and hazard index (HI) calculated on the basis of grain metal contents followed the trend, that is, C > B > A. The HI results revealed highest and lowest health risks associated with the consumption of Zincol-16 and Borlaug-16, respectively. The 'Borlaug-16' and 'sludge treatment B' are recommended for cultivation and as rate of application, respectively, for ensuring food safety and agro-ecological health.
Keywords: Biochemical; human health risk; metals; municipal sewage sludge; wheat.
Proline accumulation was a significant and reliable indicator of metal stress in wheat plants.