Nica and colleagues sampled soil, nettle leaves and newly matured Roman snails (Helix pomatia) at eight sites in western Romania in May 2011. The study distinguishes foot from hepatopancreas and examines shell traits across sites with different pollution histories. It supplies environmental-pathway evidence; the wild tissues and plants were not sampled as consumer foods.
Key numbers
Three pooled batches of 20 snails were analyzed per site, alongside three soil and three nettle samples. Concentrations are reported on a dry-weight basis. The soil method measures a dilute-nitric-acid extractable fraction. Concentration means and error bars appear only in Figures 1–4; their graphical estimates have limited precision.
Approximate chart-derived means below retain the site breakdown. All values are mg/kg dry weight; the soil column is a dilute-acid extract. These are estimates from the published bars, not exact tabulated concentrations. Error bars remain separate in the structured evidence.
| Site | Copper, snail foot | Zinc, hepatopancreas | Cadmium, hepatopancreas | Lead, soil extract |
|---|---|---|---|---|
| THM1 | ≈27.4 | ≈169.8 | ≈17.2 | ≈14.8 |
| THM2 | ≈46.8 | ≈110.6 | ≈3.2 | ≈39.4 |
| THM3 | ≈7.4 | ≈51.3 | ≈0.5 | ≈21.4 |
| THM4 | ≈8.7 | ≈80.5 | ≈1.4 | ≈53.0 |
| THM5 | ≈10.5 | ≈80.8 | ≈3.7 | ≈25.4 |
| THM6 | ≈18.9 | ≈149.0 | ≈4.8 | ≈11.6 |
| THM7 | ≈6.2 | ≈105.6 | ≈5.9 | ≈10.7 |
| THR | ≈6.6 | ≈68.5 | ≈0.5 | ≈4.8 |
These estimates support broad site and tissue comparisons. Small differences within plotting precision should not be interpreted as biological differences.
| Site | Location | Shell height, mean ± SD (unit unstated) | Whorls, mean ± SD |
|---|---|---|---|
| THM1 | Timisoara city Landfill; Parta-Sag/Timis | 3.63 ± 0.19 | 4.92 ± 0.04 |
| THM2 | South Industrial Platform; Timisoara/Timis | 3.86 ± 0.11 | 4.94 ± 0.13 |
| THM3 | North Industrial Platform; Timisoara/Timis | 3.73 ± 0.24 | 4.44 ± 0.15 |
| THM4 | East Industrial Platform; Timisoara/Timis | 3.65 ± 0.2 | 4.31 ± 0.15 |
| THM5 | Communal Road 64; Timisoara/Timis | 4.26 ± 0.2 | 4.49 ± 0.14 |
| THM6 | National Road Resita-Caransebes DN 58; Caras-Severin | 3.9 ± 0.17 | 4.8 ± 0.09 |
| THM7 | Principal Street; Otelu Rosu/Caras-Severin | 3.99 ± 0.19 | 4.66 ± 0.16 |
| THR | Salbagelu Nou; Caras-Severin | 4.18 ± 0.28 | 4.47 ± 0.14 |
Table 2 reports morphology for 20 selected shells per site. Selection of the most homogeneous shells limits population representativeness. Relative shell height is a height-to-width ratio.
Table 1 reports soil-to-nettle correlations of 0.93 for zinc (P<0.01) and 0.76 for lead (P<0.05). Soil copper versus foot copper is 0.45 and nonsignificant, despite a contrary narrative claim; nettle copper versus foot copper is 0.90 (P<0.01). These correlations do not isolate dietary uptake from soil ingestion or contact exposure.
Methods (brief)
Sites included a landfill, industrial platforms, roads and a reference village. Snails were fasted for 48 hours before freezing and dissection. Foot and hepatopancreas were analyzed separately after drying and ashing; nettle leaves were washed and similarly processed. Soil underwent 24-hour extraction with 0.5 N nitric acid. Flame atomic absorption spectrometry measured copper, zinc, cadmium and lead. Reported detection limits were 0.12, 0.21, 0.02 and 0.04 mg/kg respectively; CRM recoveries were 102%, 103%, 104% and 96%.
Evidence fitness
The paired environmental compartments show how tissue selection and local exposure history affect metal measurements. Geographic comparisons are useful within the defined collection and analytical methods. The study cannot establish a market-food concentration, edible wet-weight value, consumer exposure dose or causal contribution from any named industrial source.
Limitations
Several narrative statements disagree with Table 1 or the concentration charts. Copper in foot exceeds hepatopancreas at two sites in Figure 1, so higher hepatopancreas accumulation is not universal. Some plants exceed their paired soil extract, despite the broad claim of no soil-to-plant concentration increase. Reported degrees of freedom, correlation aggregation and several P-value intervals are internally unclear. Shell-height units are absent from Table 2, and exact concentration tables and raw replicate data are unavailable. Source-quoted soil regulatory comparisons have not been verified from primary instruments.
Related evidence
Soil-to-plant transfer of heavy metals · Source attribution and environmental burden apportionment · Copper · Zinc · Cadmium · Lead
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