Plants were sampled from four different types of chlordecone-contaminated land in Guadeloupe (West Indies). The objective was to investigate the importance of biological and agri-environmental parameters in the ability of plants to bioaccumulate chlordecone. Among the plant traits studied, only the growth habit significantly affected chlordecone transfer, since prostrate plants concentrated more chlordecone than erect plants. In addition, intensification of land use has led to a significant increase in the amount of chlordecone absorbed by plants. The use of Bayesian networks uncovers some hypothesis and identifies paths for reflection and possible studies to identify and quantify relationships that explain our data.

International audience | A novel FeSiCa rich material (IS), chicken manure (CM) and its biochar were investigated for their efficiency in simultaneous remediation of Cd and As uptake by the vegetable Brassica chinensis L. Wet chemistry analysis and X-ray powder diffraction, scanning electron microscopy/energy dispersive X-ray spectroscopy as well as Fourier transform infrared spectroscopy were used to reveal the mechanisms responsible for Cd and As fixation in the amended soils. The IS treatment performed best in reducing Cd uptake, while the combination of IS and CM was the optimal one for As fixation. The precipitation/co-precipitation (in cadmium silicate/phosphate/phosphate hydroxide, cadmium iron and manganese oxides under alkaline conditions, and calcium/magnesium/ferric arsenates) and specific chemisorption (by amorphous iron/manganese oxides) were proved to be more efficient in simultaneously lowering As and Cd phytoavailability than was organic complexation. These findings demonstrate that FeSiCa and FeSiCaC amendments are highly efficient and promising in-situ remediation systems for safe crop production on soils contaminated with Cd and As.

Mercury (Hg) and methylmercury (CH3Hg) bind strongly to micro and nano (NP) particles and this partitioning impacts their fate and bioaccumulation into food webs, and, as a result, potential human exposure. This partitioning has been shown to influence the bioavailability of inorganic Hg to methylating bacteria, with NP-bound Hg being more bioavailable than particulate HgS, or organic particulate-bound Hg. In this study we set out to investigate whether the potential interactions between dissolved ionic Hg (HgII) and CH3Hg and NPs was due to incorporation of Hg into the core of the cadmium selenide and sulfide (CdSe; CdS) nanoparticles (metal exchange or surface precipitation), or due purely to surface interactions. The interaction was assessed based on the quenching of the fluorescence intensity and lifetime observed during HgII or CH3Hg titration experiments of these NP solutions. Additional analysis using inductively coupled plasma mass spectrometry of CdSe NPs and the separated solution, obtained after HgII additions, showed that there was no metal exchange, and X-ray photoelectron spectroscopy confirmed this and further indicated that the Hg was bound to cysteine, the NP capping agent. Our study suggests that Hg and CH3Hg adsorbed to the surfaces of NPs would have different bioavailability for release into water or to (de)methylating organisms or for bioaccumulation, and provides insights into the behavior of Hg in the environment in the presence of natural or manufactured NPs.

Triclosan (TCS) is a synthetic microbial compound widely used in the formulation of various personal care products. Its frequent detection in marine ecosystems, along with its physical and chemical properties, suggest that TCS can be highly persistent, being easily bioaccumulated by biota and, therefore, eliciting various toxicological responses. Yet, TCS's mechanisms of bioaccumulation and toxicity still deserve further research, particularly focusing on the interactive effects with climate change-related stressors (e.g. warming and acidification), as both TCS chemical behaviour and marine species metabolism/physiology can be strongly influenced by the surrounding abiotic conditions. Hence, the aim of this study was to assess TCS bioaccumulation and ecotoxicological effects (i.e. animal fitness indexes, antioxidant activity, protein chaperoning and degradation, neurotoxicity and endocrine disruption) in three tissues (i.e. brain, liver and muscle) of juvenile Diplodus sargus exposed to the interactive effects of TCS dietary exposure (15.9 μg kg−1 dw), seawater warming (ΔTºC = +5 °C) and acidification (ΔpCO2 ∼ +1000 μatm, equivalent to ΔpH = −0.4 units). Muscle was the primary organ of TCS bioaccumulation, and climate change stressors, particularly warming, significantly reduced TCS bioaccumulation in all fish tissues. Furthermore, the negative ecotoxicological responses elicited by TCS were significantly altered by the co-exposure to acidification and/or warming, through either the enhancement (e.g. vitellogenin content) or counteraction/inhibition (e.g. heat shock proteins HSP70/HSC70 content) of molecular biomarker responses, with the combination of TCS plus acidification resulting in more severe alterations. Thus, the distinct patterns of TCS tissue bioaccumulation and ecotoxicological responses induced by the different scenarios emphasized the need to further understand the interactive effects between pollutants and abiotic conditions, as such knowledge enables a better estimation and mitigation of the toxicological impacts of climate change in marine ecosystems.

Knowledge of distribution of toxic metal in crop is essential for studying toxic metal uptake, transportation and bioaccumulation, and it is important for environmental pollution monitoring. In this study, the macro spatial distribution of chromium in rice leaves was visualized by re-heating dual-pulse laser-induced breakdown spectroscopy (DPLIBS) and chemometric methods. After the optimization of two important parameters (delay time and energy ratio) in DPLIBS, chromium prediction model was established based on global spectra. The global model achieved acceptable performance while slight overfitting for model was found because of numerous irrelevant variables. Feature variables including emissions from chromium and other elements were successfully selected by the values of regression coefficient in partial least square regression model. Best performance was achieved by using the feature variables and support vector machine, with correlation coefficient of prediction of 0.959, root mean square error of prediction of 13.4 mg/kg and residual predictive deviation of 3.6. Finally, the distribution of chromium in rice leaves was visualized with the best prediction model. The distribution image showed that chromium distributed approximately symmetrically along the vein and was likely to be accumulated in leaf apex. The preliminary results provide an approach for investigating the macro spatial distribution of elements in crops, which is important for environmental protection and food safety.

Whereas early life stages are usually considered as particularly sensitive to both organic and inorganic contaminants, field studies assessing contaminant bioaccumulation in these stages are scarce. Selenium (Se) is thought to counteract Hg toxic effects when it is found at Se:Hg molar ratios above 1. However, the variation of this ratio in key fish tissues of different early life stages is mostly unknown. The present study therefore aimed to assess Hg and Se content in gravid female tissues (gonads, muscle, liver, gut, and brain) and different life stages (egg masses, newly hatched larvae (NHL), larvae and juvenile) of Yellow Perch (YP) in a large fluvial lake (Lake Saint-Pierre, Québec, Canada). Se:Hg molar ratios were measured for each compartment in order to fill associated knowledge gaps. Total Hg (THg) and methylmercury (MeHg) concentration varied between tissue according to the following trend: Muscle > Liver > Gut > Brain > Gonads. During YP early life stages, MeHg values increased according to an ontogenetic pattern (mg/kg dw) (mean ± SEM): Egg masses (0.01 ± 0.002) < NHL (0.015 ± 0.001) < Larvae (0.14 ± 0.01) < Juveniles (0.18 ± 0.01). Se concentrations in different YP tissues showed the following trend (mg/kg dw) (mean ± SEM): Gut (3.6 ± 0.1) > Liver (2.5 ± 0.1) > Gonads (1.92 ± 0.06) > Brain (1.26 ± 0.03) > Muscle (1.23 ± 0.06). In YP early life stages, Se concentrations were highest in NHL (3.0 ± 0.2), and then decreased as follows: Egg masses (2.8 ± 0.1) > Larvae (1.37 ± 0.04) > Juveniles (0.93 ± 0.05). Se:Hg molar ratios varied considerably and were systematically above 1. This is the first study to simultaneously report Hg and Se bioaccumulation through fish life cycle.

Land degradation by salinization and sodification changes soil function, destroys soil health, and promotes bioaccumulation of heavy metals in plants, but little is known about their fundamental mechanisms in shaping microbial communities and regulating microbial interactions. In this study, we explored the impact of saline-alkaline (SA) stress on soil bacterial and fungal community structures in different Cd-contaminated soils of Dezhou, Baoding, Xinxiang, Beijing and Shenyang cities from the North China Plain, China. Increased soil salinity and alkalinity enhanced Cd availability, indicated by significant increases in available Cd2+ in soil solution of 34.1%–49.7%, soil extractable Cd of 32.0–51.6% and wheat root Cd concentration of 24.5%–40.2%, as well as decreased activities of antioxidative enzymes of wheat root when compared with CK (no extra neutral or alkaline salts added). Soil bacteria were more active in response to the SA stress than fungi, as the significant structural reorganization of soil bacterial microbiota rather than fungal microbiota between SA and CK treatments was illustrated by principal component analysis. Adding neutral and alkaline salts enriched oligotrophic and haloalkaliphilic taxa in the Sphingobacteriaceae, Cellvibrionaceae, and Caulobacteraceae bacterial families, but decreased some Acidobacteria such as subgroup 6_norank, which was a sensitive biomarker that responded only to Cd contamination in CK-treated soils. Conversely, fungi were more sensitive to soil differences than bacteria: the composition of the fungal community was significantly different among different soil types. Phylogenetic molecular ecological network (pMEN) analysis further indicated that the microbial community structure and network interactions were altered to strengthen the adaptability of microorganisms to SA stress; the changes in structure and network interactions were proposed to contribute to competitive interactions. Most of the keystone genera identified in SA-treated soils, such as Blastococcus, Gemmatimonas, RB41, or Candida, had relatively low abundances (<1%), indicating their disproportionate ecological roles in triggering resistance or tolerance to SA stress and Cd toxicity.

The bioaccumulation and biomagnification of 22 major perfluoroalkyl substances (PFAS) were investigated in tissues of polar bears (Ursus maritimus) and their major prey species, the ringed seal (Pusa hispida), from the Scoresby Sound region of East Greenland. In polar bear liver the mean Σ4PFSA (perfluoroalkyl sulfonic acid) concentration (C4, C6, C8 and C10) was 2611 ± 202 ng/g wet weight (ww; 99% perfluorooctane sulfonate (PFOS)) and two orders of magnitude higher than the 20 ± 3 ng/g ww (89% PFOS) concentration in fat. The mean Σ4PFSAs in seal liver was 111 ± 5 ng/g ww (98% PFOS) and three orders of magnitude higher relative to the 0.05 ± 0.01 ng/g ww concentration in blubber (100% perfluorohexane sulfonate). Perfluoro-1-octane sulfonamide (FOSA) was quantifiable in bear (mean 10 ± 1.4 ng/g ww) and seal (mean 0.6 ± 0.1 ng/g ww) liver but not in fat or blubber. The mean Σ13PFCAs (C4–C18; perfluoroalkyl carboxylic acids) in bear liver (924 ± 71 ng/g ww) was much greater than in seal liver (74 ± 6 ng/g ww). In bear fat and seal blubber, the mean Σ13PFCAs were 15 ± 1.9 and 0.9 ± 0.1 ng/g ww, respectively. Longer chain C11 to C14 PFCAs dominated in bear fat and seal blubber (60–80% of Σ13PFCA), whereas shorter-chain C9 to C11 PFCAs dominated in the liver (85–90% of Σ13PFCA). Biomagnification factors (BMFs) were orders of magnitude greater for PFHxS and C9 to C13 PFCAs when based on bear liver to seal blubber rather than bear liver to seal liver, and PFCA (C9 to C13) BMFs decreased with increasing chain length. Seal blubber to bear liver BMFs better reflects the dietary exposure relationship of PFAS between bears and seals.

Persistent organic pollutants (POPs) including PCDD/Fs, PCBs and organochlorine pesticides (OCPs) are among the most important and hazardous pollutants of soil. Food producing animals such as chicken, beef, sheep and goats can take up soil while grazing or living outdoors (free-range) and this can result in contamination.In recent decades, large quantities of brominated flame retardants such as polybrominated diphenyl ethers (PBDEs), short-chain chlorinated paraffins (SCCPs) and per- and polyfluorinated alkylated substances (PFAS) have been produced and released into the environment and this has resulted in widespread contamination of soils and other environmental matrices. These POPs also bioaccumulate and can contaminate food of animal origin resulting in indirect exposure of humans.Recent assessments of chicken and beef have shown that surprisingly low concentrations of PCBs and PCDD/Fs in soil can result in exceedances of regulatory limits in food. Soil contamination limits have been established in a number of countries for PCDD/Fs but it has been shown that the contamination levels which result in regulatory limits in food (the maximum levels in the European Union) being exceeded, are below all the existing soil regulatory limits. ‘Safe’ soil levels are exceeded in many areas around emission sources of PCDD/Fs and PCBs. On the other hand, PCDD/F and dioxin-like PCB levels in soil in rural areas, without a contamination source, are normally safe for food producing animals housed outdoors resulting in healthy food (e.g. meat, eggs, milk).For the majority of POPs (e.g. PBDEs, PFOS, PFOA, SCCP) no regulatory limits in soils exist.There is, therefore, an urgent need to develop appropriate and protective soil standards minimising human exposure from food producing animals housed outdoors. Furthermore, there is an urgent need to eliminate POPs pollution sources for soils and to control, secure and remediate contaminated sites and reservoirs, in order to reduce exposure and guarantee food safety.

Analysis of persistent halogenated organic pollutants (HOPs) in human follicular fluid is important given previous reports of their adverse effects on the reproductivity of women. In the present work, HOPs, including polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), were analyzed in 127 follicular fluid samples collected from patients who were undergoing in vitro fertilization in Central China. The concentrations of ∑₇BDEs (sum of BDE-28, -47, −99, −100, −153, −154, and −183) in follicular fluid ranged from not detected (n.d.) to 110 ng/g lipid weight (lw), with an average of 50 ± 24 ng/g lw. BDE-100 was suggested to be an indicator of BDE congeners in follicular fluid, with the highest concentrations and showing a significantly high correlation (p < 0.01) with ∑₇BDEs. Penta-BDE products were the principal source of PBDEs in follicular fluid samples. The concentrations of ∑₇CBs (CB-28, -52, −101, −118, −138, −153, and −180) in follicular fluids ranged from n.d. to 250 ng/g lw, with an average of 77 ± 69 ng/g lw. CB-28 and CB-52 were considered to be indicator CB congeners, with tri-CBs and tetra-CBs dominating in follicular fluid. No significant correlation was observed between patient age and PBDE or PCB concentrations in follicular fluid, indicating that age was not the controlling factor influencing the bioaccumulation of most HOPs in this study.