Swiercz et al. 2022 - Silver fir needles as trace-element bioindicators
Swiercz and colleagues repeated a 1986 silver-fir biomonitoring design in Swietokrzyski National Park in 2018 to compare trace elements and nutrient supply in fir needles after a multi-decade decline in regional industrial emissions. This is primary environmental biomonitoring evidence, not product or ingredient occurrence evidence. The routeable facts are the fir-needle and forest-soil concentrations for Cd, Cu, Ni, Pb, Zn, Mn, and related elements, plus the air/rainwater deposition context used to interpret the 1986-to-2018 change.
Key numbers
All tissue and soil concentration values are reported on a dry-matter basis.
Sampling frame
Two transects were sampled in Swietokrzyski National Park: transect A at Swiety Krzyz and transect B at Lysica. Each transect had five plots. In September 1986, and again in September 2018, the authors collected needles from five silver-fir trees per plot at about 3 m crown height, then sorted the material into current-year and third-year needles. One mixed sample of about 60 g represented each plot and needle-age class. The 2018 campaign also characterized four soil profiles.
Soil heavy metals in 2018
Table 3 reports these aqua-regia/ICP-OES soil concentration ranges across the four profiles and sampled horizons:
| Metal | Soil range (mg/kg d.m.) | Highest reported horizon/site |
|---|---|---|
| Cd | 0.10-0.61 | Transect B Lysica VI, A horizon |
| Cu | 4.43-12.31 | Transect B Lysica VI, A horizon |
| Ni | 8.94-33.52 | Transect B Lysica X, O horizon |
| Pb | 22.81-90.89 | Transect A Swiety Krzyz V, A horizon |
| Zn | 55.60-150.98 | Transect B Lysica VI, A horizon |
The paper states that the highest trace-element concentrations occurred in organic and organo-mineral horizons, while bedrock levels did not differ substantially.
Silver-fir needle chemistry
The needle chemistry results are presented primarily as Figures 2-5, with the narrative reporting selected maxima and trends:
| Needle result | Reported value or trend |
|---|---|
| Highest 1986 Zn | 47.60 mg/kg d.m. at plot 7, transect B Lysica |
| Highest 1986 Cu | 9.10 mg/kg d.m. at plot 8, transect B |
| Highest 1986 Pb | Average value 8.10 mg/kg d.m. at plot 3, transect A Swiety Krzyz |
| Highest 1986 Ni | 4.90 mg/kg d.m. at plot 10, transect B Lysica |
| Highest 2018 Pb | 4.55 mg/kg d.m. at plot III, transect A Swiety Krzyz |
| Pb time trend | The authors state that Pb in needles collected in 2018 was three times lower than in 1986 needles |
| Sulfur time trend | Sulfur in 2018 needles was about half the 1986 level |
| Three-year-old needle trend | Results text says Cd, Cu, Mn, and Zn in three-year-old needles decreased from 1986 to 2018 and are useful trace-element biomonitoring indicators |
Macronutrient and sulfur values provide pollution/nutrition context: sulfur peaked at 2146.00 mg/kg d.m. in 1986 at plot 1, transect A, and the lowest reported sulfur value was 510.00 mg/kg d.m. in 2018 at plot X, transect B. Calcium peaked at 9630.00 mg/kg d.m. in 1986 at plot 5, transect A, and the lowest reported calcium value was 2040.00 mg/kg d.m. in 2018 at plot X, transect B. Potassium ranged from 1463.00 to 3979.00 mg/kg d.m. in 1986 and from 1600.00 to 4200.00 mg/kg d.m. in 2018.
Atmospheric context
Table 4 shows the deposition context behind the biomonitoring change. Annual SO2 concentration in air fell from 32.09 micrograms/m3 in 1986 to 3.65 micrograms/m3 in 2018. Rainwater sulfate-sulfur fell from 18.92 to 2.48 mg/dm3 over the same comparison, and rainwater Pb fell from 0.99 to 0.16 mg/dm3.
Methods (brief)
Needles collected in 1986 were washed twice in distilled water, dried at 105 degrees C, homogenized, incinerated at 480 degrees C, digested in hydrochloric/nitric acid at a 3:1 ratio, and analyzed by Varian Techtron 1000 atomic absorption spectrophotometry. Total sulfur was determined colorimetrically by the Butters-Chenery method. The authors state that 1986 LOD, LOQ, and precision details were not available from the historical procedure, but the source laboratory was a leading Polish chemical laboratory at that time.
Needles collected in 2018 were washed twice with deionized water, dried, homogenized, digested with concentrated HCl/HNO3 in a 3:1 ratio using microwave mineralization, and analyzed by Agilent 5100 SVDV ICP-OES for Ca, Mg, K, Na, Mn, Pb, Cd, Cu, Ni, and Zn. Analyses were run in three replications with ERM-CD281 for external calibration. Soil trace metals were measured by ICP-OES after aqua-regia extraction under PN-ISO 11466 and PN-EN ISO 11885.
Implications
Certification: This source does not support HMTc product or ingredient standards. It measures forest needles, soils, and deposition in a protected Polish park, not consumer products.
App: Route to the metals and testing context pages for biomonitoring, atmospheric deposition, and dry-matter plant/soil concentration interpretation. Do not route the values to food, supplement, timber, or nursery-plant product pages.
Courses: Useful for explaining environmental bioindicators, historical-method comparability, needle-age effects, and why soil/plant-monitoring data should not be silently pooled with food occurrence data.
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Verification notes
The main source values are contained within the article. Table 3 gives extractable soil concentrations; Figures 2-5 show full needle concentration distributions, but the PDF text extraction exposes only the narrative maxima and trends, so this page does not estimate individual bar heights from the figures. The conclusion/abstract wording says Cd, Cu, Mn, and Zn in three-year-old needles showed a “significant increase” as an indicator, while the Results text states those same elements in three-year-old needles decreased from 1986 to 2018; this page records the explicit Results trend and flags the wording tension rather than deriving a new percent change.
Page history
The five most recent substantive edits to this page. 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.
| Commit | Date | Description |
|---|---|---|
| c1aef38 | 2026-06-02 | audit-queue: hamid2021-bacterial-plant-biostimulants-review → audited-promote |