###### Abstract  
The present study aims to assess the respective efficiency of Biochars (BCs) and activated carbons (ACs) to limit PCB 101, 138, 153 and 180 transfer to plants. A set of 6 high carbon materials comprising 3 BCs and 3 ACs was tested and used to amend a soil at 2% rate. Then, the two most efficient carbonaceous materials were used as an amendment of an historically contaminated soil sampled in the St Cyprien vicinity (Loire, France). An environmental availability assessment was performed using the ISO/DIS 16751 Part A assay (n = 3). For the in vivo part, _Cucurbita pepo_ were grown for 12 weeks. Significant decreases of transfer were found for both assays notably for powdered ACs (up to 98%). By contrast, significantly lower levels of transfer reduction were observed when BCs amendments were performed, ranging from 27 to 80% for environmental availability assessment and 0 to 36% for _C. pepo_. Reduction factors above 90% for the 2 selected materials were found from amended historically contaminated soils. Present results led to consider such a sequestering strategy as valuable to ensure plant production on non-dioxin-like polychlorobiphenyls (NDL-PCBs) contaminated soils.  
sequestration; transfer; NDL-PCBs; environmental availability +
Footnote †: journal: Applied  
Accepted: 1 April 2022  
Footnote †: journal: Applied  
in _C. pepo_[7] to favor root interception. The subsequent accumulation of organic pollutants in the root also depends on root characteristics, particularly the composition of membrane and parietal lipids [8] that in relation with hydrophobicity drives the retention in roots. As persistent organic pollutants (POPs) have very marked hydrophobicity characteristics (log Kow greater than 4), in the majority of plant species, these compounds are absorbed and accumulated in the roots without transfer to the vegetative aerial parts and fruits. Nevertheless, some varieties of _Cucurbitaceae_ are able to accumulate large amounts of POPs in the aerial parts depending on the number and the position of the non-dioxin-like polychlorobiphenyls (NDL-PCBs) chlorine atoms [1; 5].  
Thus, acting directly on this transfer to plants would prevent the contamination of food-products. A possible strategy to reduce this halogenated POP transfer to vegetal is to trap them in the soil by making them non-available. In this perspective, several amendment materials have already been evaluated and proven to be effective to limit the POP transfer, as assessed on root vegetables [9; 10] or through an in vitro assay [11; 12]. To limit transfer to plant, compost amendment of chlordecone (CLD) contaminated soils displayed a reduction of transfer to root vegetables by a factor of 3 to 10 compared to non-amended soils [13]. However, such data is lacking for other POPs, and also for plants known to accumulate halogenated POPs inside their aerial parts like _Cucurbitaceae_ family. Activated carbons (ACs) amendment showed also a reduction up to 90% in non-physiological based in vitro environmental availability assays [12; 14]. Some studies reported the ability of activated carbons and biochars to trap and reduce the transfer of pesticides, PCBs and other organic pollutants in cucurbits [15; 16; 17; 18; 19].  
Thus, the subject of the present study is to assess the efficiency of a trapping strategy when using different high carbon matrices as amendment material to ensure plant production on polluted agricultural land. In this frame we aimed to focus on Non-Dioxin-like Polychlorobiphenyls (NDL-PCBs).