Effects of sewage sludge on bio-accumulation of heavy metals in tomato seedlings

Abstract

The proposal to use sewage sludge (SS) on agricultural fields as a sustainable way to dispose of the waste is based on its high organic and nutrients content. However, the presence of heavy metals (HMs) in sludge can contaminate crops and accumulate in the food chain. The aim of this study was to assess changes in soil fertility, biochemical responses of tomato (Solanum lycopersicum L. cv. Rio Grande) seedlings and the availability of HMs with increased rate application of SS (0, 2.5, 5 and 7.5%). Leaf chlorophyll content, nutritional status, proline, membrane peroxidation, stomatal conductance and HM accumulation were investigated. Results showed that the soil pH decreased, whereas soil salinity, organic carbon, total N, available P and exchangeable Na, Ca, K and HM content increased significantly with increasing application rates of SS. Among the three HMs (Zn, Cu and Cr), Zn had the highest capacity for transferring from soil into plants. Low metal translocation was observed from roots to leaves. The 7.5% SS dose decreased biomass production and caused a decline in chlorophyll content and stomatal conductance. However, lipid peroxidation and proline contents increased. Therefore, the use of 2.5 and 5% doses of sewage sludge in agriculture would be an efficient and costeffective method to restore the fertility of soil and an environment-friendly solution for disposal problems.Additional key words: sewage sludge amendment; soil fertility; biochemical responses; Solanum lycopersicum.

Anaerobic digestates from sewage sludge used as fertilizer on a poor alkaline sandy soil and on a peat substrate: Effects on tomato plants growth and on soil properties

“…This beneficial effect has been already observed also in sunflower (Bourioug et al, 2018), sorghum (Alvarenga et al, 2016) and triticale (Kchaou et al, 2018). On the other hand, literature provides examples of reduction of leaf chlorophyll content in tomato after treatment with SS (Elloumi et al, 2016), which is probably due to the excessive heavy metals presence in the used SS (Singh and Agrawal, 2007). However, this aspect was likely not linked with the reduction of chlorophyll content over time observed in the present study.…”

“…As a corollary, biomass values were reflected by ANUE ones, which were higher than the ones reported in literature for tomato plants grown in pot under greenhouse conditions treated with a 10-folds higher nitrogen application (Wang et al, 2013). Improvement in terms of leaves number and chlorophyll content were less intense, but still higher than the examples reported in literature (Bakshi et al, 2019;Elloumi et al, 2016;He et al, 2016;Hossain et al, 2015).…”

Analysis of Soil Quality Status and Accumulation of Potentially Toxic Element in Food Crops Growing at Fecal Sludge Dumpsite in Ubakala, Nigeria

“…The level of EC at 1 m (33.27±0.83 mS/cm) is 1.66, 2.09, 3.40 and 3.96 fold higher than its values at 5 m, 15 m, 30 m and control, respectively. The values of EC in soil from the fecal sludge (FS) dumpsite in Ubakala, Nigeria increased from 9.79±0.58 to 33.27±0.83 mS/cm, which is higher than 1.53±0.01 to 2.46±0.02 mS/cm in waste dump soil (Obasi et al, 2013), 0.03 to 0.04 mS/cm in municipal landfilled soil (Fonge et al, 2017) and 0.58±0.07 to 0.80±0.08 dS/m in soil amended with sewage sludge (Elloumi et al, 2016) (Table 4). Electrical conductivity (EC) is a measure of soil salinity (Rhoades, 1996) and it significantly impacts microbial respiration, decomposition and other processes involved in nitrogen cycling (Smith and Doran, 1996).…”

“…The level of organic matter at 1 m (24.11±0.01) was 1.73, 3.11, 10.86 and 11.27 folds higher than its value at 5 m, 15 m, 30 m and control, respectively. The organic matter content in soil from the fecal sludge dumpsite at Ubakala, Nigeria increased from 2.22±0.02 to 24.11±0.01, which is lower than 62.49±1.63 to 70.36±0.88 % in sewage sludge in Greece (Angelidis and Aloupi, 1999) but higher than 1.5 to 1.9 (Bozym, 2019) (Table 4), 5.12±0.02 to 6.59±0.07 % in waste dump soil (Obasi et al, 2013), 3.81 to 7.94 % in municipal landfilled soil (Fonge et al, 2017) and 1.74±0.04 to 3.88±0.08 % in soil amended with sewage sludge (Elloumi et al, 2016). Soil organic matter content is an important soil quality indicator (Larson and Pierce, 1991) since it influences soil biological, physical and chemical characteristics.…”

Sewage Sludge as a Soil Amendment for Growing Biomass Plant Arundo donax L.

“…Elloumi et al [40] studied the effect of SS application (2.5%, 5% and 7.5%) on the growth of tomato (Solanum lycopersicum L. cv. Rio Grande) seedlings.…”