This study measured eight metal(loid)s in 84 surface-soil samples around the Arzew petrochemical platform. Seven metals have area-specific concentration summaries; cadmium is reported only as below 0.01 mg/kg. The paper also calculates exposure indices for hypothetical children, but it did not sample children, crops or consumer products.
Key numbers
| Source result | Reported value | Location and scope |
|---|---|---|
| Field sampling | 84 soils at 0–20 cm, plus two offsite background soils | Methods; beach 9, harbour 13, downtown 4, industrial 14, agricultural 17, road 27. |
| Agricultural-soil arsenic | Mean 11.57, median 10.41, range 4.92–19.4 mg/kg | Table 2; acid-extractable elemental arsenic, not inorganic arsenic in crops. |
| Road-soil lead | Mean 98.4, median 77.0, range 45.6–220.5 mg/kg | Table 2; SD 51.85, N=27. |
| Industrial-soil chromium | Mean 51.17, median 45.36, range 11.33–193.36 mg/kg | Table 2; SD 49.32, N=14, no chromium speciation. |
| Cadmium | All study samples below 0.01 mg/kg | Results; the paper does not identify this value as a formal detection or quantitation limit. |
Area-specific means, medians, minima, maxima, SDs and distribution descriptors are preserved for all seven tabulated metals. The two background samples remain separate. Prose statements that conflict with the table are retained as distinct source reports.
Methods (brief)
Soils were sieved, air-dried and ground before aqua-regia microwave digestion and ICP-AES. Each sample had triplicate analytical readings; these do not increase the number of field samples. The authors report lot blanks and a sandy-clay reference material with accuracy within 100 ± 10%. The collection date and metal-specific detection limits are not supplied. Aqua-regia results are operationally defined acid-extractable concentrations; the procedure does not demonstrate complete dissolution of every soil mineral.
Evidence fitness
Supports environmental-soil occurrence and qualified spatial context. No food, wipe or human biological samples were measured. The arsenic and chromium results cannot establish inorganic arsenic or Cr(VI). Correlations and principal components describe associations, without proving causal source fractions.
Limitations
Several narrative values and area labels disagree with the tables. The text calls some reference values PNECs that differ from its own comparator table, and its interpolated map scales differ from measured extrema. Source-quoted French comparators have not been verified from the primary instruments.
The abstract describes cancer risk, while the methods calculate non-cancer hazard quotients and indices. Chromium was not speciated, bioavailability was not measured, and modeled exposure is not an observed health outcome. Hypothetical combined-index values and their input assumptions therefore remain qualified model context. A single campaign, small area cohorts and absent per-site raw data constrain quantitative reuse.
Related evidence
- Soil-to-plant transfer of heavy metals
- Source attribution and environmental burden apportionment
- Cat 2 (Children Personal Care) non-ingestion exposure pathways
- Arsenic
- Cadmium
- Chromium
- Cobalt
- Copper
- Nickel
- Lead
- Zinc
Update history
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