Genotoxicity of organic extracts of urban airborne particulate matter: an assessment within a personal exposure study

Airborne particulate matter, PM(10) and PM(2.5), are associated with a range of health effects including lung cancer. Their complex organic fraction contains genotoxic and carcinogenic compounds such as polycyclic aromatic hydrocarbons (PAHs) and their derivatives. This study evaluates the genotoxicity of the PM(10) and PM(2.5) organic extracts that were sampled in the framework of a personal exposure study in three French metropolitan areas (Paris, Rouen and Strasbourg), using the comet assay, performed on HeLa S3 cells. In each city, 60-90 non-smoking volunteers composed of two groups of equal size (adults and children) carried the personal Harvard Chempass multi-pollutant sampler during 48h along two different seasons ('hot' and 'cold'). Volunteers were selected so as to live (home and work/school) in 3 different urban sectors contrasted in terms of air pollution within each city (one highly exposed to traffic emissions, one influenced by local industrial sources, and a background urban environment). Genotoxic effects are stronger for PM(2.5) extracts than for PM(10), and greater in winter than in summer. Fine particles collected by subjects living within the traffic proximity sector present the strongest genotoxic responses, especially in the Paris metropolitan area. This work confirms the genotoxic potency of particulate matter (PM(10) and PM(2.5)) organic extracts to which urban populations are exposed.     

Removal of xenobiotics from effluent discharge by adsorption on zeolite and expanded clay: an alternative to activated carbon?

Xenobiotics such as pesticides and pharmaceuticals are an increasingly large problem in aquatic environments. A fixed-bed adsorption filter, used as tertiary stage of sewage treatment, could be a solution to decrease xenobiotics concentrations in wastewater treatment plants (WWTPs) effluent. The adsorption efficiency of two mineral adsorbent materials (expanded clay (EC) and zeolite (ZE)), both seen as a possible alternative to activated carbon (AC), was evaluated in batch tests. Experiments involving secondary treated domestic wastewater spiked with a cocktail of ten xenobiotics (eight pharmaceuticals and two pesticides) known to be poorly eliminated in conventional biological process were carried out. Removal efficiencies and partitions coefficients were calculated for two levels of initial xenobiotic concentration, i.e, concentrations lower to 10 μg/L and concentrations ranged from 100 to 1,000 μg/L. While AC was the most efficient adsorbent material, both alternative adsorbent materials showed good adsorption efficiencies for all ten xenobiotics (from 50 to 100 % depending on the xenobiotic/adsorbent material pair). For all the targeted xenobiotics, at lower concentrations, EC presented the best adsorption potential with higher partition coefficients, confirming the results in terms of removal efficiencies. Nevertheless, Zeolite presents virtually the same adsorption potential for both high and low xenobiotics concentrations to be treated. According to this first batch investigation, ZE and EC could be used as alternative absorbent materials to AC in WWTP.     

Inhibition equivalency factors for microcystin variants in recombinant and wild-type protein phosphatase 1 and 2A assays

In this work, protein phosphatase inhibition assays (PPIAs) have been used to evaluate the performance of recombinant PP1 and recombinant and wild-type PP2As. The enzymes have been compared using microcystins-LR (MC-LR) as a model cyanotoxin. Whereas PP2A_Rec provides a limit of detection (LOD) of 3.1 μg/L, PP1_Rec and PP2A_Wild provide LODs of 0.6 and 0.5 μg/L, respectively, lower than the guideline value proposed by the World Health Organization (1 μg/L). The inhibitory potencies of seven MC variants (-LR, -RR, -dmLR, -YR, -LY, -LW and -LF) have been evaluated, resulting on 50 % inhibition coefficient (IC₅₀) values ranging from 1.4 to 359.3 μg/L depending on the MC variant and the PP. The PPIAs have been applied to the determination of MC equivalent contents in a natural cyanobacterial bloom and an artificially contaminated sample, with multi-MC profiles. The inhibition equivalency factors (IEFs) have been applied to the individual MC quantifications determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the estimated MC-LR equivalent content has been compared to PPIA results. PPIAs have demonstrated to be applicable as MC screening tools for environmental applications and to protect human and animal health.     

Chronic dietary exposure to pyrolytic and petrogenic mixtures of PAHs causes physiological disruption in zebrafish—part II: behavior

In the last 10 years, behavior assessment has been developed as an indicator of neurotoxicity and an integrated indicator of physiological disruption. Polycyclic aromatic hydrocarbon (PAH) release into the environment has increased in recent decades resulting in high concentrations of these compounds in the sediment of contaminated areas. We evaluated the behavioral consequences of long-term chronic exposure to PAHs, by exposing zebrafish to diets spiked with three PAH fractions at environmentally relevant concentrations. Fish were exposed to these chemicals from their first meal (5 days postfertilization) until they became reproducing adults (at 6 months old). The fractions used were representative of PAHs of pyrolytic (PY) origin and of two oils differing in composition (a heavy fuel oil (HO) and a light crude oil (LO)). Several tests were carried out to evaluate circadian spontaneous swimming activity, responses to a challenge (photomotor response), exploratory tendencies, and anxiety levels. We found that dietary PAH exposure was associated with greater mobility, lower levels of exploratory activity, and higher levels of anxiety, particularly in fish exposed to the HO fraction and, to a lesser extent, the LO fraction. Finally, our results indicate that PAH mixtures of different compositions, representative of situations encountered in the wild, can induce behavioral disruptions resulting in poorer fish performance.     

Developmental toxicity of PAH mixtures in fish early life stages. Part I: adverse effects in rainbow trout

A new gravel-contact assay using rainbow trout, Oncorhynchus mykiss, embryos was developed to assess the toxicity of polycyclic aromatic hydrocarbons (PAHs) and other hydrophobic compounds. Environmentally realistic exposure conditions were mimicked with a direct exposure of eyed rainbow trout embryos incubated onto chemical-spiked gravels until hatching at 10 °C. Several endpoints were recorded including survival, hatching delay, hatching success, biometry, developmental abnormalities, and DNA damage (comet and micronucleus assays). This bioassay was firstly tested with two model PAHs, fluoranthene and benzo[a]pyrene. Then, the method was applied to compare the toxicity of three PAH complex mixtures characterized by different PAH compositions: a pyrolytic extract from a PAH-contaminated sediment (Seine estuary, France) and two petrogenic extracts from Arabian Light and Erika oils, at two environmental concentrations, 3 and 10 μg g^?1 sum of PAHs. The degree and spectrum of toxicity were different according to the extract considered. Acute effects including embryo mortality and decreased hatching success were observed only for Erika oil extract. Arabian Light and pyrolytic extracts induced mainly sublethal effects including reduced larvae size and hemorrhages. Arabian Light and Erika extracts both induced repairable DNA damage as revealed by the comet assay versus the micronucleus assay. The concentration and proportion of methylphenanthrenes and methylanthracenes appeared to drive the toxicity of the three PAH fractions tested, featuring a toxic gradient as follows: pyrolytic?Arabian Light?Erika. The minimal concentration causing developmental defects was as low as 0.7 μg g^?1 sum of PAHs, indicating the high sensitivity of the assay and validating its use for toxicity assessment of particle-bound pollutants.     

Ant cuticular response to phthalate pollution

Phthalates are common atmospheric contaminants used in the plastic industry. Ants have been shown to constitute good bioindicators of phthalate pollution. Hence, phthalates remain trapped on ant cuticles which are mostly coated with long-chain hydrocarbons. In this study, we artificially contaminated Lasius niger ants with four phthalates: dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), di(2-ethylhexyl) phthalate (DEHP), and benzyl butyl phthalate (BBP). The first three have previously been found on ants in nature in Touraine (France), while the fourth has not. The four phthalates disappeared rapidly (less than 5 days) from the cuticles of live ants. In contrast, on the cuticles of dead ants, DEHP quantities remained unchanged over time. These results indicate that phthalates are actively absorbed by the cuticles of live ants. Cuticular absorption of phthalates is nonspecific because eicosane, a nonnatural hydrocarbon on L. niger cuticle, was similarly absorbed. Ants are important ecological engineers and may serve as bioindicators of ecosystem health. We also suggest that ants and more generally terrestrial arthropods may contribute to the removal of phthalates from the local environment.     

Effectiveness of control strategies against Botrytis cinerea in vineyard and evaluation of the residual fungicide concentrations

This investigation was undertaken to test different control strategies against Botrytis cinerea vineyards. Two commercial vineyards, “Barbera” and “Moscato,” located in Piedmont (Northern Italy) were divided into seven plots and treated with different combinations of fungicides including fenhexamid, pyrimethanil, fludioxonil + cyprodinil, iprodione, and boscalid, a new carboxamide compound. An integrated strategy including a chemical (pyrimethanil) and a biocontrol agent (Trichoderma spp. t2/4ph1) was also included. At harvest, the percentage of bunches and berries attacked by B. cinerea and the concentration of the chemical fungicides were determined. All the pesticide residues at harvest were below the maximum residue level (MRL), except when two applications of pyrimethanil per season were applied. Boscalid was the most effective active ingredient against B. cinerea among the tested chemicals. When boscalid application was followed by a treatment with pyrimethanil, its efficacy was similar to that shown by two treatments of pyrimethanil. However, this second strategy was not feasible due to the risks of resistance development in the pathogen and to the residue accumulation as indicated by the analysis.     

Pedogenesis and nickel biogeochemistry in a typical Albanian ultramafic toposequence

This study aimed at relating the variability of Ni biogeochemistry along the ultramafic toposequence to pedogenesis and soil mineralogy. Hypereutric Cambisols dominate upslope; Cambic Vertisols and Fluvic Cambisols occur downslope. The soil mineralogy showed abundance of primary serpentine all over the sequence. It is predominant upslope but secondary smectites dominate in the Vertisols. Free Fe-oxides are abundant in all soils but slightly more abundant in the upslope soils. Whereas serpentines hold Ni in a similar and restricted range in every soil (approx. 0.3 %), Ni contents in smectites may vary a lot and Mg-rich and Al-poor smectites in the Vertisol could hold up to 4.9 % Ni. Ni was probably adsorbed onto amorphous Fe-oxides and was also exchangeable in secondary smectites. High availability of Ni in soils was confirmed by DTPA extractions. However, it varied significantly along the toposequence, being higher in upslope soils, where Ni-bearing amorphous Fe-oxides were abundant and total organic carbon higher and sensibly lower downslope on the Vertisols: Ni_DTPA varied from 285 mg kg^?1 in the surface of soil I (upslope) to 95.9 mg kg^?1 in the surface of Fluvic Cambisols. Concentration of Ni in Alyssum murale shoots varied from 0.7 % (Hypereutric Cambisols) to 1.4 % (Hypereutric Vertisol). Amazingly, Ni uptake by A. murale was not correlated to Ni_DTPA, suggesting the existence of specific edaphic conditions that affect the ecophysiology of A. murale upslope.