Bioaccessibility of lead in Dittrichia viscosa plants and risk assessment of human exposure around a fertilizer industry in Lebanon.

Total and bioaccessible lead (Pb) concentrations in Dittrichia viscosa and soil samples were considered for estimating the potential health risk, related to both plant intake and accidental soil ingestion by adult and child consumers, near a Lebanese fertilizer plant. A total of 27 plant samples, from 9 uncultivated sites situated around the plant, were analyzed in order to assess the total and bioaccessible Pb content. Physiologically based extraction test (PBET) was used to estimate oral bioaccessibility of Pb in edible plant parts. Washed and unwashed leaves were compared in order to show the importance of good consumer practice on Pb intake. Extracted Pb in the intestinal medium accounted for 24 up to 87% of Pb extracted in the gastric medium. The total hazard quotient (HQtot) and the total bioaccessible hazard quotient (BHQ), related to both plants' intake and soil ingestion, for two maximalist child and adult scenarios, were calculated in order to estimate human health risk assessment. HQtot estimations considering the total concentration of Pb in soil and plant suggest that this metal is a contributor in elevating health risks problems on local plants' consumers, especially children inhabitants. However, the integration of bioaccessible concentrations of Pb in risk estimations reduces remarkably the potential risk.

Bioaccessibility and radioisotopes of lead in soils around a fertilizer industry in Lebanon.

The use of phosphate ore by fertilizer industries is considered a major source of soil contamination by trace metals and radionuclides. Despite its low mobility and bioavailability, lead (Pb) is among soil contaminants that pose a serious risk to human health. This study evaluates the potential impact of a fertilizer factory in North Lebanon on the total content of Pb and the activity concentration of its radioisotopes in residential, non-agricultural lands around the industry, as well as its mobility and bioaccessibility in soil samples collected at different depths. Chemical extractions by EDTA and in vitro physiologically based extraction test were used to estimate, respectively, the available and bioaccessible fractions of Pb in soils. Radioisotopes 214Pb, 212Pb and 210Pb have been analyzed by gamma spectrometry. Different physicochemical soil parameters, such as pH, carbonate content, electrical conductivity, cation exchange capacity, clay, total nitrogen and redox potential, were studied. The pseudo-total Pb varied between 12.8 and 68.5 mg kg-1, while the extractable fractions were more variable, between 12 and 72% of total Pb concentration for the EDTA extracted fraction and up to 28.5% for the bioaccessible fractions. The processing of the data shows the decreases with depth in most sites of the total and available Pb and of the activity concentration of 210Pb and their positive correlations with total nitrogen. These variations and relationships with the location of studied sites show the influence of emissions from the factory or the transport of ore and by-products. The correlations between available and bioaccessible Pb on one hand, between available Pb and 210Pb on another hand, raise the question of health risk assessments taking into account the bioaccessibility of Pb and its radioisotopes.

Potential of Technosols Created with Urban By-Products for Rooftop Edible Production.

Urban agriculture is sprouting throughout the world nowadays. New forms of urban agriculture are observed such as rooftop farming. In the case of low-tech rooftop farming projects, based on recycled urban waste, one of the key issues is the type of substrate used, as it determines the functions and ecosystem services delivered by the green roof. Using a five year experimental trial, we quantified the food production potential of Technosols created only with urban wastes (green waste compost, crushed wood, spent mushroom), as well as the soil fertility and the potential contamination of food products. Regarding food production, our cropping system showed promising results across the five years, in relation with the high fertility of the Technosols. This fertility was maintained, as well as the nutrients stocks after five cropping years. Most of the edible crops had trace metals contents below existing norms for toxic trace metals with nevertheless a concern regarding certain some trace metals such as Zn and Cu. There was no trace metal accumulation in the Technosols over time except for Zn. This study confirmed that constructing Technosols only from urban wastes is a suitable and efficient solution to design rooftops for edible production.

[Biomononitoring of environmental exposure to inorganic arsenic]. / Surveillance biologique de l'exposition environnementale à l'arsenic inorganique.

BACKGROUND AND OBJECTIVES: The French national authority for health (Haute autorité de santé: HAS) and the French clinical toxicology society (Société de toxicologie clinique: STC) received a formal request from the French ministry for heath to elaborate recommendations for the screening of environmental overexposure to inorganic arsenic (iAs), for the medical management of overexposed patients and for the medical surveillance of exposed population. To allow these recommendations, preliminary literature retrieval and analysis were performed for identifying validated indicators of both exposure and early effects of iAs and their levels in the general population living in France. METHODS: Evaluations of inorganic arsenic toxicity conducted by national or international health agencies during the last 3 decades were all examined and analyzed. These evaluations were completed by literature retrieval through Medline and Scopus from January 2016 to December 2019. RESULTS AND CONCLUSIONS: The best biomonitoring indicator for iAs exposure is the sum of urine iAs, monmomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) concentrations (SAs). The upper limit of confidence interval of the 95th percentile of the distribution of this parameter in the general adult population living in France is 10 µg/g of creatinine, and is recommended as the limit value for the definition of overexposure. In less than 12 year-old children specific limit values are required, but not yet available. In their absence, SAs should exceed both 10 µg/g creatinine and 11 µg/L to be considered as indicating a probable overexposure to iAs. There are no useful biological indicators of iAs early effects. Non carcinogenic skin effects of inorganic arsenic (hyperpigmentation and keratosis) should be considered as the earliest deleterious effects of repeated environmental iAs exposure.

Kinetic characterizing of soil trace metal availability using Soil/EDTA/Chelex mixture.

The kinetic aspects are not usually tackled when mimicking the soil trace metal mobilization. In this work, a simple procedure is developed for measuring the kinetics of Pb, Cu and Cd transfer from the soil solid phase towards a resin sink. A ternary system of Soil/EDTA/Chelex was employed for mimicking the metal transfer from two agricultural soil samples into the Chelex. Two different kinetic regimes (P(1) and P(2)) were observed. The kinetic profile of Pb was distinctly different from those of Cd and Cu. Basing on kinetic principles, two kinetic models were proposed for estimating the apparent rate constants of leaching and removal processes in, respectively, two binary mixtures of soil/EDTA and EDTA extracts/Chelex. Contrary to Pb, solid phase pools of Cd and Cu exchanged with the solution on short time scales. The kinetic rate of desorption occurred in following order: Pb

Development of a new microelectrolysis system for in-situ electrodeposition of ultra-traces of gold prior to measurement by ETAAS.

Electrodeposition is known to be suitable for separation and preconcentration of extremely low concentrations of analyte from bulk samples and is instrumentally is very simple. In this approach a new combined system was designed for in-situ electrodeposition of ultratrace levels of gold from micro samples on to a graphite furnace prior to determination by electrothermal atomic absorption spectrometry (ETAAS). Sediment samples were digested and traces of the gold content were extracted with boiling aqua regia. To prevent the highly corrosive effect of aqua regia media, the graphite tube surface was pre-coated by electrodeposition of ppm amounts of Pd prior to sample introduction. Separation of the analyte from the matrix was achieved by electrodeposition of the analyte in situ on the Pd/C surface of the furnace tube. Vanadium was also used as a modifier to stabilize the analyte from decomposition at charring temperatures. By using the proposed microelectrolysis preconcentration technique a considerable improvement in sensitivity and detection limit was achieved compared with conventional ETAAS. Characteristic masses for ED-ETAAS techniques in both nitric acid and aqua regia were reported to be m(o)=4.1 pg, with %RSD=2.9; the calculated LOD was 0.105 ppb, and typical calibration graphs for this element in nitric acid and aqua regia for both techniques were linear up to 70 microg L(-1) with about 99% recovery. Six reference sediments samples were tested by the proposed technique and by the Conv-ETAAS method. The results were in agreement with recommended values (reported by a reference laboratory using UV-visible spectrometry), demonstrating the efficiency of extraction and preconcentration of ultratrace levels of gold.