phytoremediation of soils contaminated with potentially toxic

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

• kg− 1), Pb (4473 mg kg− 1) and Zn (3147 mg kg− 1), and amended with 3% biochar (C + B). Biochar
• The contaminated soil was collected within a range of 3.5 km from the Montevecchio dismissed mining site located in the
• as a sandy loam (USDA textural classification, 67% sand, 15% silt, 18% clay). The composite soil was divided in 2 subsamples:
• chemical properties are listed in Table S1.
• time, they were mixed once a week and kept at 40% of their water-holding capacity (WHC). The WHC value chosen was derived from
• preliminary laboratory tests, and was attributable to the soil characteristics, as at values above 40% WHC the soil became muddy. After
• chemical properties (Table 1). Soil pH and electric conductivity (EC) were measured in 1:2.5 (w/v) solid to water suspension; cation
• included, with PTE recoveries around ±10% of the certified values.
• Selected chemical characteristics of control (C) and biochar amended (C + B) soils (mean ± SE, n = 3).
• Ash (%) 90.7 ± 0.05a 86.3 ± 0.02b
• Total C (%) 1.63 ± 0.03b 3.50 ± 0.01a
• Total N (%) 0.08 ± 0.01a 0.11 ± 0.01a
• terranean climate (8,9,12) and are potentially suitable for the successful phytoremediation of PTEs-contaminated soils. Pots were
• arranged according to a completely randomized design and plants were grown over 3 months, from April to July 2021, in a naturally-lit
• greenhouse at an average temperature of 20–25 ◦ C and 60–70% relative humidity. The application of biochar was the only source of
• mixture of 69% HNO3 and ultrapure H2O (ratio 1:1), in a Microwave Milestone MLS 1200 (EPA Method 3052), using FAAS for Zn and
• Fig. 1. Cd (A), Pb (B), and Zn (C) released after sequential extraction procedure (mg kg− 1, means ± SE; n = 3) in control (C) and biochar amended
• The biochar used in this study was characterized by a very alkaline pH (i.e., 9.9), a high total carbon content (i.e., ~84%), and high
• concentrations of Ca, K, and Mg (Table S1). Although the biochar derived from P. nigra grown in a contaminated soil, its Cd, Pb, and Zn
• to the soil caused an increase of pH, DOC (+50%) and organic matter (+2.14-fold), as well as exchangeable Ca and K and available P
• (+5, +123, and +50%, respectively) (Table 1), confirming the potential of biochar at improving the quality and fertility of
• ~66, 7, and 38% of the total Cd, Pb and Zn respectively. It is important to emphasize that the PTEs concentration in Fraction 1 in C-soil
• this fraction represents the most mobile and potentially bioavailable pool, accountable for environmental and human health risks (38).
• The biochar application (C + B-soil) reduced the F1 of Cd, Pb and Zn by 29, 27 and 52% respectively compared to the C-soil (Fig. 1).
• exchangeable pool. The fractions extracted with NaOAc (F2) were 3, 39, and 15% of the total Cd, Pb, and Zn respectively. The con­
• The relatively immobile, and not readily bioavailable or leachable pool of PTEs (F3) accounted for 7, 38 and 15% of the Cd, Pb and
• Zn total. The addition of biochar increased the Na2-EDTA extractable fraction of Pb (+10%) and Zn (+26%), while the effect was not
• 42% of the total Pb, highlighting strong interactions between Pb and biochar functional groups (e.g. –COOH and –OH phenolics (41))
• The residual fraction of PTEs (F4), i.e. the very insoluble and/or occluded PTEs, was 17, 17 and 32% of the total Cd, Pb and Zn
• Fig. 2. Roots and shoots dry weight (g plant− 1, mean ± SE; n = 3) of A = hairy vetch and B = annual ryegrass (alone and in mixture) grown in
• of biochar in the immobilization of Zn (32). The addition of biochar decreased the residual fraction of Pb (<31% in the C + B soil). This
• from soluble (potentially bioavailable, F1) to more stable (hardly bioavailable, F3 and F4) ones.
• In vetch alone (Fig. 3), shoots and roots concentration of Cd, Pb and Zn was reduced by 67 and 41%, 25 and 32% and 55 and 54%,
• Fig. 3), whilst it reduced Cd concentration by 27% and 18% in the roots of C and C + B respectively; a similar reduction was observed
• by shoots increased in intercropped vetch compared to monoculture (e.g. +16, 47 and 42% for Cd, Pb and Zn respectively in C-plants).
• ryegrass, reduced Zn concentration by 20% in roots, and Pb concentration by 15% in shoots in C soil (Fig. 4). This is consistent to what
• Overall, biochar, mixed cropping and their combination influenced PTEs uptake by plants differently (Table 2). Biochar proved to
• Fig. 3. Cd (A), Pb (B), and Zn (C) in shoots and roots (mg kg− 1, mean ± SE; n = 3) of hairy vetch grown alone or in mixture, in control (C) and
• biochar amended (C + B) soils. For the meaning of the letters and asterisk (*) on top of each bar, see the caption of Fig. 2.
• Fig. 4. Cd (A), Pb (B), and Zn (C) in shoots and roots (mg kg− 1, mean ± SE; n = 3) of annual ryegrass grown alone or in mixture, in control (C) and
• biochar amended (C + B) soils. For the meaning of the letters and asterisk (*) on top of each bar, see the caption of Fig. 2.
• respectively, were >1 for Cd and Zn in C vetch (Table 3). The BAF values of Cd and Zn were higher than Pb, indicating higher con­

Methods (brief)

• The contaminated soil was collected within a range of 3.5 km from the Montevecchio dismissed mining site located in the
• for more than a century (1848–1991) to extract Pb and Zn from galena (PbS) and sphalerite ((Zn,Fe)S). Soil samples were randomly
• collected from the top soil layer (0–30 cm), pooled in the laboratory to obtain a composite soil that was air-dried, sieved to <2 mm,
• as a sandy loam (USDA textural classification, 67% sand, 15% silt, 18% clay). The composite soil was divided in 2 subsamples:
• the contact, soil sub-samples were air-dried and chemical analyses were carried out to evaluate the influence of biochar on soil
• sample. Pseudo-total PTEs concentration (i.e. Cd, Pb and Zn) was quantified in soil, after digestion with aqua regia reverse solution
• (HNO3/HCl, 3:1 v/v) and microwave mineralization (Milestone MLS1200), using a PerkinElmer AAnalyst 200 flame atomic absorption
• spectrometer (FAAS) for Zn quantification and a PerkinElmer AAnalyst 400-HGA 900 graphite furnace atomic absorption spectrometer
• (GFAAS), for Pb and Cd quantification. A standard reference material (NIST-SRM 2711A) for quality assurance and quality control was
• The influence of biochar on Cd, Pb and Zn mobility was determined in triplicate independent soil samples collected from each
• surface-complexed and precipitated PTEs (F3). Following each step of the sequential extraction, samples were centrifuged and filtered
• mixture of 69% HNO3 and ultrapure H2O (ratio 1:1), in a Microwave Milestone MLS 1200 (EPA Method 3052), using FAAS for Zn and
• GFAAS for Pb and Cd quantification. Peach leaves were used as standard reference material (NIST-SRM 1547).

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Shellfish (shrimp, crab, lobster, clams, oysters, mussels)
• Root-Vegetable Purees
• Cadmium
• Arsenic

Verification notes

• Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
• Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
• Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
• Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
• HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.