Impact of different effluents on the performance and heavy metal accumulation of Lettuce (Lactuca sativa L.).

Abstract

A study was conducted to see the impact of different effluents on the growth, yield and heavy metals content of lettuce grown in pots during the year 2012-13 and 2013-14. The pots were arranged in a completely randomized design (CRD) with six treatments (effluents) replicated four times. The treatments included 10% effluents of sugar mill, sewage water, soap factory, ghee mill, slaughterhouse and Control. Data on weight of leaves plant^-1 (g), number of leaves plant^-1, leaf area, yield ha^-1, pH, Vitamin C and heavy metals (Fe, Pb, Zn, Ni, Cd) were recorded and statistically analyzed by computing Analysis of variance (ANOVA) and using Least Significant Difference (LSD) test.

The results indicated that irrigation with effluents significantly affected all parameters studied. Sewage water, sugar mill effluent and slaughterhouse wastage significantly improved the yield and growth characteristics while ghee mill and soap factory effluents reduced these traits. The highest yield and related characteristics were recorded with sewage water followed by slaughterhouse wastage and sugar mill effluent. Irrigation with sewage water increased 37.6% yield while the increment with slaughterhouse wastage and sugar mill effluent was 32.1 and 11.2%. Ghee mill and soap factory effluents reduced 30.8 and 14.5%, respectively. Heavy metal concentrations were increased with all types of effluents. The highest values for Pb, Zn and Cd were reported in plants irrigated with sewage water while Fe and Ni were highest in slaughterhouse wastage and ghee mill effluent applied plants, respectively. The transfer factors showed that the accumulation of metals was in the order of Pb > Fe = Zn > Ni > Cd.

Keywords: Lettuce (Lactuca sativa L.), effluents, growth, yield, composition, heavy metal accumulation