Research PaperOrganochlorine POPs sequestration strategy by carbonaceous amendments of contaminated soils: Toward a better understanding of the transfer reduction to laying hens
Graphical Abstract
Introduction
Pollution caused by anthropogenic activities is of growing concern in the past decades, and Persistent Organic Pollutants (POPs), as laid down in Stockholm Convention (UNEP, 2011), represent the most concerning group due to their proven ecotoxicological and toxicological harmful effects and their persistence in the environment. Among these POPs, Polychlorinated biphenyls (PCBs) (Doick et al., 2005), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) (Terzaghi et al., 2020), and Chlordecone (CLD) (Cabidoche et al., 2009) are recognized to persist for decades to centuries in soil due to their retention by the soil organic matter. PCBs and PCDD/Fs are found ubiquitously at background concentrations in soils (Gis Sol, 2011; Meijer et al., 2003) whereas soil of the French West Indies are extensively contaminated by CLD (Cabidoche et al., 2009, Collas et al., 2019, Le Déaut and Procaccia, 2009). Animals may ingest significant amounts of soil (Collas et al., 2019, Jurjanz et al., 2012) and thus be exposed to contaminants accumulated in soil. Laying hens are a particularly exposed species for two reasons: they may ingest up to 25% of soil in nonoptimal rearing conditions (Jondreville et al., 2010, Waegeneers et al., 2009) and they are able to efficiently absorb organochlorine compounds bound to soil particles they ingest (Fournier et al., 2012, Jondreville et al., 2013, Stephens et al., 1995). Such exposure leads to PCBs (Fournier et al., 2015, Fournier et al., 2012), PCDD/Fs (Schuler et al., 1997, Stephens et al., 1995), and CLD (Jondreville et al., 2014) bioaccumulation in egg yolk, adipose tissue, and liver. Moreover, eggs originated from contaminated areas and free-range laying hens may exceed the Maximum Residues Limits (MRLs) as laid down in EU regulation for PCBs or PCDD/Fs (Knutsen et al., 2018) as well as for CLD (Jurjanz et al., 2020). Indeed for eggs, even relatively low concentrations in soil may lead to contamination of eggs above these MRLs for PCBs and PCDD/Fs (Weber et al., 2018) as for CLD (Jurjanz et al., 2020). Soil ingestion constitute the most sensitive exposure pathway to POPs (Weber et al., 2019).
This emphasizes the urgent need to reduce the exposure of laying hens to preserve poultry production in these contaminated areas. Waegeneers et al. (2009) proposed preventive measures to reduce contamination exclusively based on adapted husbandry practices. We propose another strategy based on sequestration of these POPs in order to reduce their bioavailability and subsequently the contamination of animal foodstuffs. The use of porous matrices, like biochars and activated carbons (ACs), was extensively studied in the past decade. AC was successfully used to eliminate the bioavailability of 2,3,7,8-TCDD in mice (Boyd et al., 2017, Sallach et al., 2019), or of PCDD/Fs and PCBs in laying hens (Fujita et al., 2012). These experiments were conducted using contaminated feed and not soil. The use of biochars or ACs was also demonstrated to be efficient in order to reduce the bioavailability of NDL-PCBs in swine (Delannoy et al., 2014a) or chlordecone in swine (Delannoy et al., 2019, Delannoy et al., 2018) and goats (Yehya et al., 2017) following ingestion of contaminated soils.
The aim of this study was to assess the capacity of several carbonaceous matrices (ACs, Biochars) presenting contrasted porosity characteristics to limit the transfer of organochlorine compounds from contaminated soils to laying hens.
Section snippets
Production and acquisition of condensed materials
A set of 6 distinct highly carbonaceous materials was obtained: (i) 3 commercial ACs (ROTH Sochiel E.U.R.L., Lauterbourg, France) and (ii) 3 biochars produced by CARBOFRANCE (Montier-sur-Saulx, Lorraine, France) by pyrolysing oak (500 °C or 700 °C) or Japanese knotweed (700 °C). After the pyrolysis process, biochars samples were ground and sieved to < 500 µm.
Characterization of carbonaceous matrices
BET Specific Surface Areas (SSA) of all ACs and BCs were determined at PrimeVerre Montpellier. The measurements were performed using a
ACs and BCs textural characteristics
Overall, a large panel of different textural properties was observed from the set of condensed materials as shown by the specific surface areas ranging from 31 to 1142 m2 g−1 (Table 3). As previously described, biochars displayed the lowest specific surface area (between 31 and 281 m2 g−1) and ACs the highest (between 566 and 1142 m2 g−1). Regarding biochars, BC2 displayed a higher surface area than BC1 (281 ± 11 m2 g−1 vs 31 ± 2 m2 g−1 respectively), confirming that higher pyrolysis
Conclusion
Sequestration strategy reduces significantly the transfer of halogenated POPs, particularly for PCDD/Fs and PCB 77 (up to 82% TEQ basis). However, almost no significant reduction was observed when using the 500 °C biochar, few for the other BCs whereas ACs were the most efficient to limit the bioavailability of these halogenated compounds. Thus, micro- and mesoporous surfaces appeared as the characteristics explaining the most these results.
In addition, the efficiency of the methodology
CRediT authorship contribution statement
Nadine El Wanny: Conceptualization, Methodology, Investigation, Data curation, Formal analysis (supporting) Writing – original draft, Visualization (supporting), Yves Le Roux: Conceptualization(supporting), Methodology, Data curation, Formal analysis,Writing – review & editing, Visualization (supporting), Agnès Fournier: Conceptualization(supporting), Methodology, Writing – review & editing, Supervision (supporting), Project administration, Moomen Baroudi: Writing – review & editing
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgment
The authors are grateful to the Agency for ecological transition (Agence de l'environnement et de la maîtrise de l'énergie - ADEME, Angers, France) for their financial and scientific supports during the PIEGEACHLOR project (grant number: 1672C0042). We thank CARBOFRANCE and N. Simon (Montiers-sur-Saulx, France) to have provided the biochar matrices. We thank P. Hartmeyer (Université de Lorraine, EA 3998) for the care of the animals and for her valuable technical support concerning the soil and
References (66)
- et al.
Transfer of persistent organic pollutants in food of animal origin – meta-analysis of published data
Chemosphere
(2021) - et al.
Sorption of native polyaromatic hydrocarbons (PAH) to black carbon and amended activated carbon in soil
Chemosphere
(2008) - et al.
Long-term pollution by chlordecone of tropical volcanic soils in the French West Indies: a simple leaching model accounts for current residue
Environ. Pollut.
(2009) - et al.
Cattle exposure to chlordecone through soil intake. The case-study of tropical grazing practices in the French West Indies
Sci. Total Environ.
(2019) - et al.
Effects of condensed organic matter on PCBs bioavailability in juvenile swine, an animal model for young children
Chemosphere
(2014) - et al.
Amendment of soil by biochars and activated carbons to reduce chlordecone bioavailability in piglets
Chemosphere
(2018) - et al.
Relative bioavailability to laying hens of indicator polychlorobiphenyls present in soil
Chemosphere
(2012) - et al.
Suppressive effect of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls transfer from feed to eggs of laying hens by activated carbon as feed additive
Chemosphere
(2012) - et al.
Influence of activated charcoal amendment to contaminated soil on dieldrin and nutrient uptake by cucumbers
Environ. Pollut.
(2009) - et al.
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and biphenyls (PCBs) in home-produced eggs
Chemosphere
(2016)