Table 1.
Summary of bioavailability/bioaccessibility data of contaminants from CCA-treated wood sites.
| Organism | Exposure Medium | Exposure Route | Fraction of Source | Total Concentration | Total Background Concentration | Bioavailability Test | Bioavailability/Bioaccessibility | Ref. |
|---|---|---|---|---|---|---|---|---|
| Whole-cell bacterial bioreporters | ||||||||
| Soil | As, Escherichia coli pJAMA arsR; Cu, Pseudomonas fluorescens DF57-Cu15 | Soil-water extractable metalloid | Soil: As, 1364; Cr, 540; Cu, 1662. (mg /kg) |
n/a | Bioreporter’s specific gene expression *; and analyzed by ICP-MS | (Bioavailable) As, 6.1 ± 0.8; Cr, na; Cu, 8.2 ± 0.6 (mg/kg) ** |
[58] | |
| Earthworm (Eisenia andrei) | ||||||||
| Humus soil layer | Earthworms ingestion |
Soil from a 60 year-old Norway spruce (Picea abies L.) stand | Soil: As, 10.1 ± 5.5–2810 ± 921; Cr, 12.5 ±10.6–1480 ± 355; Cu 5.14 ± 5.3–642 ± 180 (mg/kg) |
As, 6.12 ±1.2; Cr, 5.3 ± 1.7; Cu, 4.7 ± 1.1 (mg/kg) | Animal chemical digestion and analyzed by ICP-OES |
(Bioavailable) As, 22–357.1; Cr, 0.9–40.8; Cu, 7.7–51.1 (mg/kg body eight) ** |
[61] | |
| Children | ||||||||
| Surface soil (<250 μm fraction) | Incidental ingestion | CCA-treated playground structures 16 and 26 yrs-old installation | Soil: As, 101.3–213.5 (mg/kg) |
As, 4.6–6.6 (mg/kg) | In vitro SBRC-gastric assay | (Bioaccessible) As, 24.5–29.4% of total As (109–236 mg/kg) in the <250 μm fraction | [62] | |
| Plant (Spinacia oleracea) | ||||||||
| Artificial soils: sandy soil with 3.8% coir peat, 13.5% perlite and 82.7% sand; clay soil with mixing sandy soil with 10% bentonite | Spinach leaf and root | Irrigation with untreated leachate; water from submerged timber blocks; and irrigation with tap water (no As, Cr and Cu) on soil mixed with shredded timber (powder < 15 mm) | Soil: As, 5–176; Cr, 5–252; Cu, 5–127 (mg/kg) |
n/a | Plant chemical digestion and analyzed by ICP-MS |
(Bioavailable) Sandy soil (Leaf) As, 0.2–1.5; Cr, 0.5–2.9; Cu, 0.8–4.4; (Root) As, 20–62; Cr, 0.6–1.3; Cu, 2.3–10 Clay soil (Leaf) As, 0.3–0.9; Cr, 0.3–1.8; Cu, 1–4.24; (Root) As, 9–148; Cr, 0.7–61; Cu, 3.8–59 (mg/kg plant wet weight) ** |
[63] | |
| Whole-cell bacterial bioreporters children | ||||||||
| Soil | Cu-specific Pseudomonas fluorescens bioreporter | Soil-water extractable concentration: As, 0.17–18.3; Cr, 0.02–0.78; Cu, 0.11–5.99 (mg/kg) | Soil: As, 32.4–2839; Cr, 26.1–1819; Cu, 17.2–2205 (mg/kg) | n/a | Bioreporter’s specific gene expression * | (Bioavailable) As, na; Cr, na; Cu, 0.04–3.52 mg/kg |
[64] | |
| Whole-cell bacterial bioreporters children | ||||||||
| Soil and wood treated staircases/railings | Hand-to-mouth incidental ingestion | Soil and surface wipe (50 cm2) (construction years from 1978–1998) | Soil: As, 1.2–66.6 mg/kg. Surface wipes (dislodgeable As): 5.4–86.1 μg/100 cm2 | Soil: As, 1.2–3.1 mg/kg. Surface wipes: As, <0.2 μg/100 cm2 | Soil: In vitro SBRC-gastric assay; Surface wipes: analyzed by ICP-MS |
(Bioaccessible) Soil: As, 1.2–25.2 mg/kg (17–84%). Hand loadings: As, 15–23.8 μg/100 cm2 |
[65] | |
| Human | ||||||||
| Soil | Incidental ingestion | Soil-water extractable metalloid | Soil: As, 170 ± 35 mg/kg | n/a | In vitro gastrointestinal bioaccessibility | (Bioaccessible) As, 30.5 ± 3.6% (17 ± 0.4–46 ± 1.1%) | [66] | |
| Earthworm (Eisenia fetida) | ||||||||
| Soil | Earthworms Ingestion |
CCA-treated wood–water leachates | Soil: As, 13–169; Cr, 12–151; Cu, 10–216 (mg/kg). Wood leachate As, 325 ± 4; Cr, 291 ± 3.4; Cu, 248 ± 4.2 (mg/L) | Untreated wood leachate: As, 0.5 ± 0.7; Cr, 0.35 ± 0.5; Cu, 0.55 ± 0.8 (mg/L) | Earthworm growth and reproduction test; and analyzed by ICP-OES | (Bioaccessible) Ranged from negligible to As, 80; Cr, 89; Cu, 90 (mg/kg) | [67] | |
| Children | ||||||||
| Soil | Incidental ingestion | Soil immediately adjacent CCA-treated utility poles after 18 months of service | Soil: As, 37.4 ± 2.5–251 ± 12 mg/kg | n/a | In vitro astrointestinal method | (Bioaccessible) As, 25.0 ± 2.7–66.3 ± 2.3 % (mean value 40.7 ± 14.9%) | [68] | |
| Human / mix of plant species | ||||||||
| Soil | Phytotoxicity | Soil used from 1942 to 1968 for CCA wood impregnation | Soil: As, 5904 ± 194; Cr, 3829 + 161; Cu, 1509 ± 90 (mg/kg) |
n/a | Physiologically based extraction test [69]; and analyzed by ICP-OES | (Bioaccessible) Soil: As, 219 ± 10; Cr, 26.1 **; Cu, 581 ± 30. Plant shoots: As, 78.6 ± 0.3; Cr, 7.4 ± 0.1; Cu, 48.5 ± 0.2 (mg/kg) | [60] | |
| Soil microbial community structure | ||||||||
| Soil | As, E. coli plasmid R733 recombinant with plasmid pTOO31 | Soil metal contamination from 1950 to 1998 |
Soil: As,190–2500; Cr, 250–1900; Cu, 140–950 (mg/kg) |
As, Cr and Cu were below 80 mg/kg | Bioreporter’s specific gene Expression *; and analyzed by ICP-MS |
(Bioavailable) As, 0.25–10.3 mg/L (5.1–42.3% of total water-soluble As concentration) |
[70] | |
n/a; not available. (mg/kg) when not stated otherwise, refers to milligram per kilogram dried weight. (*) Bioavailability defined as metalloid concentration capable of inducing bioreporter’s specific gene expression within an incubation period. (**) Approximate values retrieved from graph.