Metal phyto-accumulation potential, biochemical response, and health risk assessment of selected wheat varieties grown in municipal sewage sludge amended soils

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 (<i>p</i> < 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.