What are the solutions to secure animal production systems in areas contaminated with chlordecone?
The results presented in a succinct manner below will be presented at the "Chlordecone: health and environment" conference which will take place in Fort de France on October 16 and 17, 2018.
To date, nearly 1/4 of the usable agricultural area of the two French overseas departments (Guadeloupe, Martinique) are considered moderately or highly polluted by Chlordecone (CLD). A national survey conducted since 2008 in the slaughterhouses of the French West Indies revealed an unexpected contamination of products of animal origin. CLD was quantified in about one-third of cattle carcasses from contaminated agricultural areas, and nearly 10% of carcasses were found to be non-compliant. This worrying situation prompted industry professionals as well as agricultural research and development stakeholders to set up studies to understand the processes of contamination and the fate of chlordecone in the body in order to propose relevant solutions to ensure the safety of animal products.
Livestock exposed to chlordecone and unintentionally contaminated by ingestion of environmental matrices can be decontaminated within a few weeks
Recent work (Lastel et al., 2016, Fournier et al., 2017) has made it possible to characterize the fate of the molecule in the body of ruminants. Once the animal is removed from a contaminated plot, the half-lives of chlordecone in the body are relatively short compared to many other persistent organic pollutants (between 20 and 40 days depending on the species) and allow to consider periods of decontamination of animals from risk areas, on time steps compatible with farming practices. It must be remembered that the application of a decontamination period of 3.3 times the half-life time allows to eliminate 90% of the chlordecone from the body of animals. Species abacus construction is underway and will allow this decontamination time to be determined as a function of initial tissue concentration and target endpoint. Work in progress does not only concern chlordecone but also its metabolites. Thus, analytical development has been carried out to simultaneously quantify CLD and CLDOH in their free and conjugated forms. The methods were validated on three animal matrices (liver, feces and urine). The analysis was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS / MS) and extraction by QuEChERS methods. (Quick, Easy, Cheap, Efficient, Rugged and Safe) (Saint Hilaire et al., 2018). These analytical methods provide a better understanding of the detoxification mechanisms of chlordecone in livestock.
Livestock exposure via soil ingestion is directly dependent on herbage allowance. It is therefore essential to promote feeding practices that minimize this route of exposure.
Several recent studies have shown that chlordecone from contaminated soil (nitisol or andosol) is not retained by organic or mineral fractions of the soil during digestive processes. Thus, the work of Bouveret et al. (2013) and Jurjanz et al. (2014) reveal that soil chlordecone can be assimilated by both swine and ruminant species. It is therefore necessary to identify grazing practices that minimize the daily amount of soil ingested. The determination of soil ingestion at grazing uses complex methodologies mastered by the INSSICCA project partners under metropolitan conditions (Jurjanz et al, 2012). In order to be applied to the West Indian context, it was necessary to adapt the methodological approaches based on a naturally occurring element in the soil and the grass and which perfectly fulfilled the conditions to be a reliable marker of soil ingestion. In situ experiments used titanium as a marker of soil ingestion. Initial results indicate that practices of tethered grazing lead to daily soil ingestions which can reach nearly 10% of total ingested dry matter, which represents daily soil ingestion levels in the order of 100 g of soil per 100 kg live weight, when daily herbage allowance is restricted (Jurjanz et al., 2017). When the daily herbage allowance is ad libitum, the ingestion of soil is limited to 2% of the dry matter ingested daily, ie about 50 g of soil per 100 kg of live weight (Collas et al., In preparation). The results highlight an inverse relationship between herbage allowance and soil ingestion. It is therefore to promote herbage allowances that minimize soil ingestion.
A promising way: to sustainably trap chlordecone in the soil via the amendment by activated carbons or biochars.
In order to evaluate the potential for CLD sequestration in contaminated soils, biochars and activated charcoal based on locally available biomass (coconut and sargasso) were produced and characterized. The biochars prepared generally have low specific surface areas, their activation leads to a very significant increase in the specific surface area, therefore to a more efficient adsorption. The bioaccessibility and environmental availability tests have clearly demonstrated the efficiency of activated carbons in reducing the mobility of chlordecone (up to 90%). Activation treatment is critical in the sequestration process. Oak and coconut activated carbon activated with phosphoric acid represent to date the best candidates for CLD sequestration (Yehya et al., 2017). Experiments were realized in pigs and young ruminants and show that it is possible with highly carbonaceous matrices to strongly sequester the CLD. These experiments were performed under optimal sequestration conditions, in particular using artificial soils, and must therefore be confirmed (Yehya et al., 2017). If confirmed, it would be a second effective lever for controlling animal exposure.
References
Bouveret C., Rychen G., Lerch S., Jondreville C., Feidt C., 2013. Relative bioavailability of tropical volcanic soil-bound Chlordecone in piglets ». J. Agric. Food Chem. Vol. 61, n°38, 9269‑9274.
Fournier A., Feidt C., Lastel M.-L., Archimede H., Thome J.-P., Mahieu M., Rychen G., 2017. Toxicokinetics of chlordecone in goats: Implications for risk management in French West Indies. Chemosphere, 171, 564‑570
Jurjanz S., Feidt C., Pérez-Prieto L. A., Ribeiro Filho H. M. N., Rychen G., Delagarde R., 2012. Soil intake of lactating dairy cows in intensive strip grazing systems. Animal, 6, 1350‑1359
Jurjanz S., Jondreville C., Mahieu M., Fournier A., Archimède H., Rychen G., Feidt C., 2014. Relative bioavailability of soil-bound chlordecone in growing lambs. Environ. Geochem. Health, 36, 911‑917.
Jurjanz, S., Collas, C., Lastel, M.-L., Godard, X., Archimède, H., Rychen, G., Mahieu, M., Feidt, C., 2017. Evaluation of soil intake by growing Creole young bulls in common grazing systems in humid tropical conditions. Animal, 11 (8), pp. 1363-1371.
Lastel, M.-L., Lerch, S., Fournier, A., Jurjanz, S., Mahieu, M., Archimède, H., Feidt, C., Rychen, G., 2016. Chlordecone disappearance in tissues of growing goats after a one month decontamination period - effect of body fatness on chlordecone retention. Environmental Science and Pollution Research, 23 (4), pp. 3176-3183.
Saint-Hilaire, M., Inthavong, C., Bertin, T., Lavison-Bompard, G., Guérin, T., Fournier, A., Feidt, C., Rychen, G., Parinet, J., 2018. Development and validation of an HPLC-MS/MS method with QuEChERS extraction using isotopic dilution to simultaneously analyze chlordecone and chlordecol in animal livers Food Chemistry, 252 (-), pp. 147-153.
Yehya, S., Bakkour, H., Eter, D., Baroudi, M., Feidt, C., 2017. Adsorption isotherm and kinetic modeling of chlordecone on activated carbon derived from dates stones. Journal of Applied Sciences Research, 13 (2), pp. 20-28.
Yehya, S., Delannoy, M., Fournier, A., Baroudi, M., Rychen, G., Feidt, C., 2017. Activated carbon, a useful medium to bind chlordecone in soil and limit its transfer to growing goat kids. PLOS ONE, 12 (7), pp. e0179548--.
