Soil ingestion, a key determinant of exposure to environmental contaminants. The case study of chlordecone exposure in free-range pigs in the French West Indies

• Published in: Environmental pollution (1987) Vol. 316; no. 1; p. 120486
• Main Authors: Collas, Claire, Gourdine, Jean-Luc, Beramice, David, Badot, Pierre-Marie, Feidt, Cyril, Jurjanz, Stefan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2023; Elsevier
• Subjects: Chlordecone; Exposure risk; Feeding behaviour; Life Sciences; Plant cover; Soil intake; Soil-bound pollutants; LP; MRL; FM; HP; DM; Soil intake; Soil-bound pollutants; MW; LW; CR; Exposure risk; Chlordecone; BW; Plant cover; CLD; SP; Feeding behaviour; Soil -bound pollutants
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2022.120486

Ingested soil may expose free-range animals to environmental pollutants. In pigs, soil ingestion is few described whereas their burrowing behaviour suggests that it could be high. Although highly productive pigs are generally reared indoor, free-range farming is increasing in view of ethical considerations for animal welfare and is a common practice for subsistence agriculture systems. The experiment lasted 8 weeks (2 for adaptation, 6 for measurements) with 24 growing pigs of Guadeloupean Creole (CR) or Large White (LW) breeds. Pigs were assigned to 3 outdoor treatments: high pasture HP (>60 days of regrowth), low pasture LP (35 days of regrowth), and sweet potato SP (sweet potato field). Titanium (soil marker) and chromium (faecal output marker) contents of faeces, vegetation and soil samples were used to estimate individual daily soil ingestions. The average, 10th and 90th percentiles were 440, 200 and 726 g of dry soil per 100 kg body weight, respectively, without significant differences between the 3 outdoor treatments or the 2 breeds but with a significant period (i.e. week of measurements) × treatment interaction (P < 0.001). In the French West Indies, animals may be exposed to chlordecone (CLD), a very persistent organochlorine insecticide. Simulations of CLD tissue contamination due to ingestion of contaminated soil were carried out and compared to the maximum residue limit. These results show that grazing management needs to be adapted to effectively limit soil ingestion by pigs and the impact of a contaminated environment on the sustainability of pig systems.
[Display omitted]
•Ingestion of soil can be a major route for pig exposure to environmental contaminants.•Pigs are able to ingest on average over 400 g of soil per 100 kg of body weight.•Soil ingestion in free-range pigs is higher than in herbivorous species.•Outside practices have to be adapted to limit exposure to soil-bound pollutants.