Abstract
The application of sewage sludge (SS) to agricultural soils offers a sustainable solution for waste management, allowing nutrient recycling through crop production. Heavy metals (HMs) in SS can accumulate in soils and crops, posing risks to the environment and bioaccumulation in the food chain. This study investigated the impact of SS amendment on biomass production, HMs uptake (As, Cd, Cr, Cu, Ni, Pb, and Zn) by four crops (chicory, tobacco, tomato and sorghum), and soil properties (pH, electrical conductivity, and HMs content) in a greenhouse experiment. A set of 4.5 L pots were filled with soil-sludge mixture for Typic Argiudoll (S1) and Typic Hapludoll (S2) soils at a 1.56% SS-soil dry weight ratio. Sewage sludge treatment reached 39 Mg ha−1 of dry SS. The amendment increased biomass production by 2.9–3.1 folds in chicory and tobacco respectively. All crops took up higher amounts of HMs from soils after SS application. Heavy metals concentrations in plant tissues remained below phytotoxic levels and crops were safe for consumption. At post-harvest, SS addition to S1 (acid soil) increased pH but reduced pH of S2 (alkaline soil). Electrical conductivity increased in S1 soil with SS. Soil HMs concentrations after SS application met agricultural regulations. Under these conditions, applying SS to agricultural soils represents a safe disposal procedure. Additionally, as different crops led to varying residual HMs concentrations, we suggest crop rotations to improve SS application sustainability. Monitoring the evolution of HMs levels in soils and plants under field conditions with extended SS land application remains essential to protect and preserve long-term soil health.
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Claims 15
Claim · model-written summary
Sewage sludge increased chicory biomass 2.9-fold.
- Taxon
- chicory
Cichorium intybuse0 - Treatment
- sewage sludgee1
- Outcome
- biomass productione0
- Direction
- increasede0
- Value
- 2.9e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amendment increased biomass production by 2.9–3.1 folds in chicory and tobacco respectively”
e1“sewage sludge (SS)”
Claim · model-written summary
Sewage sludge increased tobacco biomass 3.1-fold.
- Taxon
- tobacco
Nicotiana tabacume0 - Treatment
- sewage sludgee1
- Outcome
- biomass productione0
- Direction
- increasede0
- Value
- 3.1 foldse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amendment increased biomass production by 2.9–3.1 folds in chicory and tobacco respectively”
e1“sewage sludge (SS)”
Claim · model-written summary
Chicory took up more heavy metals after sewage sludge.
- Taxon
- chicoryCichorium intybuse1
- Treatment
- SS applicatione0
- Outcome
- amounts of HMse0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All crops took up higher amounts of HMs from soils after SS application”
e1“chicory, tobacco, tomato and sorghum”
Claim · model-written summary
Tobacco took up more heavy metals after sewage sludge.
- Taxon
- tobaccoNicotiana tabacume1
- Treatment
- SS applicatione0
- Outcome
- amounts of HMse0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All crops took up higher amounts of HMs from soils after SS application”
e1“chicory, tobacco, tomato and sorghum”
Claim · model-written summary
Tomato took up more heavy metals after sewage sludge.
- Taxon
- tomato
Solanum lycopersicume1 - Treatment
- SS applicatione0
- Outcome
- amounts of HMse0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All crops took up higher amounts of HMs from soils after SS application”
e1“chicory, tobacco, tomato and sorghum”
Claim · model-written summary
Sorghum took up more heavy metals after sewage sludge.
SorghumNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All crops took up higher amounts of HMs from soils after SS application”
e1“chicory, tobacco, tomato and sorghum”
Claim · model-written summary
Plant tissue metal concentrations remained below phytotoxic levels.
Verbatim
e0“Heavy metals concentrations in plant tissues remained below phytotoxic levels and crops were safe for consumption”
e1“chicory, tobacco, tomato and sorghum”
Claim · model-written summary
The authors judged the crops safe for consumption.
Verbatim
e0“crops were safe for consumption”
e1“chicory, tobacco, tomato and sorghum”
Claim · model-written summary
Sludge increased pH in acidic S1 soil.
Not reportedTaxonComparator
Verbatim
e0“SS addition to S1 (acid soil) increased pH”
Claim · model-written summary
Sludge reduced pH in alkaline S2 soil.
Not reportedTaxonComparator
Verbatim
e0“reduced pH of S2 (alkaline soil)”
e1“SS addition to S1 (acid soil)”
Claim · model-written summary
Sludge increased electrical conductivity in S1 soil.
Not reportedTaxonComparator
Verbatim
e0“Electrical conductivity increased in S1 soil with SS”
Claim · model-written summary
Soil heavy metal concentrations after sludge application met agricultural regulations.
Not reportedTaxon
Verbatim
e0“Soil HMs concentrations after SS application met agricultural regulations”
Claim · model-written summary
Different crops left varying residual soil heavy metal concentrations.
Not reportedDirection
Verbatim
e0“different crops led to varying residual HMs concentrations”
Claim · model-written summary
The authors recommend crop rotations to improve sludge application sustainability.
Verbatim
e0“we suggest crop rotations to improve SS application sustainability”
e1“All crops took up higher amounts of HMs from soils after SS application”
Claim · model-written summary
The authors recommend long-term field monitoring of soil and plant heavy metals.
- Taxon
- plantsViridiplantaee0
- Outcome
- Monitoring the evolution of HMs levels in soils and plantse0
- Setting
- field conditionse0
Verbatim
e0“Monitoring the evolution of HMs levels in soils and plants under field conditions with extended SS land application remains essential to protect and preserve long-term soil health”
The same questions in other papers
organic · yield · Nicotiana tabacum (tobacco)Results agree
9 papers in the same direction as this paper
- positive
- positive
- positive
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See all 10 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.