Abstract
This study presents a series of laboratory experiments conducted to investigate the effects of elevated contaminant concentrations on phytoremediation of soils with mixed contaminants. A silty clay (typical field soil) was spiked with naphthalene and phenanthrene [representative polycyclic aromatic hydrocarbon (PAH) contaminants] and lead, cadmium, and chromium (representative heavy metals) in increased concentrations. Avena sativa (oat plant), and Helianthus annuus (sunflower) were grown in these contaminated soils and in uncontaminated (clean) soil for comparison purposes. The results showed that an increase in contaminant concentrations negatively influenced plant growth and biomass, with the sunflower showing lower germination, survival, growth, and biomass rates under increasing contaminant concentrations. However, the sunflower was relatively more effective than the oat plant for phytoextraction of heavy metals under all of the contaminant concentrations studied. Both plants caused higher chromium reduction than lead and cadmium reduction within the soil for all of the tested conditions. The final PAH concentrations did not indicate a significant decrease in PAH degradation due to the presence of plants. The phenanthrene concentrations in the final planted and unplanted pots were considerably lower than in the initial samples. Overall, plant growth and heavy metal phytoextraction were reduced with an increase in the contaminant concentrations.
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Claims 6
Claim · model-written summary
Increasing contaminants reduced sunflower germination, survival, growth and biomass.
- Taxon
- sunflower
Helianthus annuuse0 - Treatment
- increasing contaminant concentrationse0
- Outcome
- germination, survival, growth, and biomass ratese0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the sunflower showing lower germination, survival, growth, and biomass rates under increasing contaminant concentrations”
e1“Helianthus annuus (sunflower)”
Claim · model-written summary
Sunflower phytoextracted heavy metals more effectively than oat under all tested concentrations.
- Taxon
- sunflowerHelianthus annuuse0
- Outcome
- phytoextraction of heavy metalse0
- Direction
- more effectivee0
- Comparator
- oat plante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the sunflower was relatively more effective than the oat plant for phytoextraction of heavy metals under all of the contaminant concentrations studied”
Claim · model-written summary
Both plants reduced chromium in soil more than lead and cadmium.
- Taxon
- Avena sativa (oat plant), and Helianthus annuus (sunflower)Helianthus annuus
Avena sativae1 - Outcome
- chromium reductione0
- Direction
- highere0
- Comparator
- lead and cadmium reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both plants caused higher chromium reduction than lead and cadmium reduction within the soil for all of the tested conditions”
e1“Avena sativa (oat plant), and Helianthus annuus (sunflower)”
Claim · model-written summary
Plants did not significantly decrease PAH degradation.
- Taxon
- Avena sativa (oat plant), and Helianthus annuus (sunflower)Helianthus annuusAvena sativae1
- Treatment
- presence of plantse0
- Outcome
- PAH degradatione0
- Direction
- did not indicate a significant decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The final PAH concentrations did not indicate a significant decrease in PAH degradation due to the presence of plants”
e1“Avena sativa (oat plant), and Helianthus annuus (sunflower)”
Claim · model-written summary
Phenanthrene concentrations in final planted pots were considerably below initial samples.
- Taxon
- Avena sativa (oat plant), and Helianthus annuus (sunflower)Helianthus annuusAvena sativae1
- Outcome
- phenanthrene concentrationse0
- Direction
- lowere0
- Comparator
- initial samplese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The phenanthrene concentrations in the final planted and unplanted pots were considerably lower than in the initial samples”
e1“Avena sativa (oat plant), and Helianthus annuus (sunflower)”
Claim · model-written summary
Phenanthrene concentrations in final unplanted pots were considerably below initial samples.
Not reportedTaxon
Verbatim
e0“The phenanthrene concentrations in the final planted and unplanted pots were considerably lower than in the initial samples”
The same questions in other papers
impurity · growth · Helianthus annuus (common sunflower)Results agree
1 paper in the same direction as this paper
- no effect
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.