Probabilistic health risk assessment based on Monte Carlo simulation for pesticide residues in date fruits of Iran

Environmental Science and Pollution Research - The validation of an analytical procedure based on the quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach is presented for...     

Noise exposure of pregnant mice induces heart defects in their fetuses

To determine the effects of noise exposure on hearts of newborn mice, 48 pregnant mice were exposed to recorded aircraft flight noise (100?dB) for 150?min from the 2nd day of pregnancy to 7th day after delivery. Mice of the same age were selected as control group. The weights and crown-rump lengths of the fetuses and the newborns were measured, and their hearts were removed under deep anesthesia on the 1st, 7th, and 14th days after birth and prepared histologically. Quantitative changes of the hearts were measured stereologically by the Cavalieri method. The ultrastructural changes of cardiac myocytes were examined using transmission electron microscopy. No histological changes were observed, but the volumes of newborns’ hearts in the experimental groups increased significantly compared to the control group. Photomicrographs of cardiac muscle cells revealed nuclear envelope changes, chromatin condensation, and increased mitochondria and myofibrils in noise-exposed newborns. It is concluded that the newborns of pregnant mice exposed to noise stress have hypertrophic hearts with ultrastructural changes.     

Relationships between exposure to polyhalogenated aromatic hydrocarbons and organochlorine pesticides and the risk for developing type 2 diabetes: a systematic review and a meta-analysis of exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

A systematic review was performed to evaluate the association between environmental exposures to polyhalogenated aromatic hydrocarbons (PHAHs) and organochlorine (OC) pesticides and the risk for type 2 diabetes (T2D). Searches of EMbase, Google Scholar, Medline, and Scopus were performed. Reports were included if they were original human studies whose design included a control group and if the sample size was larger than 10 participants per group. The articles were excluded if the type of diabetes was unknown or Type 1. Odds ratios (OR), 95% confidence intervals (CI), and modified Naranjo scores for the effects of environmental contaminants were determined for each study. Of the 35 eligible studies, six were included in the meta-analysis; these focused specifically on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Meta-analysis of these studies showed no significant increased OR for the development of T2D from exposure to TCDD. However, subgroup analysis showed significant elevated OR for the development of T2D if exposure is repeated and accompanied by exposure to other persistent pesticides (OR?=?1.48; 1.10–1.90) but a decreased odds for T2D with exposure resulting from accidental exposure (OR?=?0.46; 0.39–0.52). Our results suggest that there are significant risks of developing T2D in populations with recurring exposures to TCDD in concert with other persistent chlorinated pesticides. A mean Naranjo score of 2.0 was determined for all 35 articles; this score was 2.5 when examining only TCDD studies and 2.1 when examining studies that looked only at T2D. Each of these Naranjo scores suggests a possible association between the prevalence of T2D and exposure to PHAHs or OC pesticides.     

Microbial Degradation of UV-Pretreated Low-Density Polyethylene Films by Novel Polyethylene-Degrading Bacteria Isolated from Plastic-Dump Soil

Eleven effective low-density polyethylene (LDPE)-degrading bacterial strains were isolated and identified from landfill soil containing large amounts of plastic materials. The isolates belonged to 8 genera, and included Pseudomonas (areroginosa and putida), Sphingobacterium (moltivorum), Delftia (tsuruhatansis), Stentrophomonas (humi and maltophilia), Ochrobacterum (oryzeae and humi), Micrococcus (luteus), Acinetobacter (pitti), and Citrobacter (amalonaticus). Abiotic degradation of LDPE films by artificial and natural ultraviolet (UV)-exposure was analyzed by FT-IR spectroscopy. LDPE films treated with UV-radiation were also inoculated with the isolates and biofilm production and LDPE degradation were measured. Surface changes to the LDPE induced by bacterial biofilm formation were visualized by Scanning Electron Microscopy. The most active bacterial isolate, IRN19, was able to degrade polyethylene film by 26.8?±?3.04% gravimetric weight over 4 weeks. Analysis of 16S rRNA sequence of this isolate revealed 96.97% similarity in sequence to Acinetobacter pitti, which has not previously been identified as a polyethylene-degrading bacterium. Also, most the effective biofilm forming isolate, IRN11, displayed the highest cell mass production (6.29?±?0.06 log cfu/cm²) after growth on LDPE films, showed 98.74% similarity to Sphingobacterium moltivourum.     

Cadmium removal from Cd-contaminated soils using some natural and synthetic chelates for enhancing phytoextraction

The influence of a natural (citric acid) and two synthetic chelates (HEDTA, EGTA) on Cd phytoextraction with radish was studied. The experiment was conducted with Cd treatments including 0 (control), 5, 20, 60 and 100?mg?Cd?kg^?1 soil. When plants were fully developed, the designated HEDTA, EGTA and citric acid were applied to establish experimental treatments. Ten days after chelate applications, soil and plant samples were taken. Results indicated that synthetic chelates can considerably increase Cd concentration in soil solution compared with citric acid. Among the applied chelates, HEDTA provided more significant influences on soil solution. Cadmium concentration in both shoots and roots of radish was increased due to enhancing influence of chelate applications on Cd concentration in soil solution. Cadmium concentration in radish shoots was more than that of roots. This can be attributed to higher bioavailability and solubility of Cd in soil solution. In all treatments which received HEDTA, the cadmium concentration in both shoots and roots of radish was increased more than that of other applied chelates. Although HEDTA is more efficient in phytoextracting Cd than other chelates, due to durability of synthetic chelates toxic effects on soils, we recommend using larger amounts of light acids.     

DNA damage in workers exposed to formaldehyde at concentrations below occupational exposure limits

Formaldehyde has been classified in group 1 as a potential source of human carcinogen by the International Agency for Research on Cancer. In this study, we evaluated the DNA damage in workers who were occupationally exposed to formaldehyde during the manufacture of melamine dinnerware.

Age, sex, smoking habits, and socioeconomic status were matched by the controls (n = 34) of workers not occupationally exposed to formaldehyde. The median value of formaldehyde time weighted average exposure in three workshops was 0.086 mg/m³. No significant difference was observed between sex and smoking habit in the assessed workers. Alkaline comet assay of peripheral blood lymphocytes was used to determine the DNA damage in the subjects. Olive moment was significantly higher in the exposed group compared with the control group.

Overall, the results suggest that respiratory exposure to low concentrations of formaldehyde causes DNA damage in peripheral blood lymphocyte. Therefore, exposure to formaldehyde should be reduced to the lowest possible level.     

Determination of trace amounts of zirconium in real samples after microwave digestion and ternary complex dispersive liquid–liquid microextraction

In this study, a ternary Zr(IV) system with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) and fluoride was chosen on the basis of dispersive liquid–liquid microextraction method. Zirconium was extracted into the fine droplets of dichlorobenzene as extracting solvent. These drops dispersed as a cloud in the aqueous sample with the help of ultrasonic waves, and the procedure was done. Finally, atomic absorption spectrometry was applied for the determination of zirconium. The effects of different factors that influence complex formation and extraction, such as pH, amounts of complexing agents, type and volume of the extracting solvent, as well as sonication and centrifuging time, were optimized. Under optimum conditions, the calibration curve was linear in the range of 150.0–800.0 ng mL^?1 with a limit of detection of 44.0 ng mL^?1. Relative standard deviation was calculated to be 4.1 % (n?=?7, c?=?400.0 ng mL^?1). The enrichment factor was 80. The proposed method was successfully used to determine the zirconium in several water, wastewater, and soil samples.     

The US’ Food and Drug Administration, Normativity of Risk Assessment, GMOs, and American Democracy

The process of risk assessment of biotechnologies, such as genetically modified organisms (GMOs), has normative dimensions. However, the US’ Food and Drug Administration (FDA) seems committed to the idea that such evaluations are objective. This essay makes the case that the agency’s regulatory approach should be changed such that the public is involved in deciding any ethical or social questions that might arise during risk assessment of GMOs. It is argued that, in the US, neither aggregative nor deliberative (representative) democracy ought to be used to make such determinations. Instead, participatory (deliberative) democracy should be the means by which members of the polity decide which normative concerns ought to underlie FDA’s assessment of GMOs. This paper uses a hypothetical case involving a new GM seed to make that argument.     

Measurement techniques for organizational safety causal models: Characterization and suggestions for enhancements

Through a review of literature from diverse disciplines with actual and potential application to causal modeling of organizational safety risk, this paper explores issues regarding measurement techniques in a quantitative safety analysis context. The interdependencies of modeling perspectives, constructs, and measures are indentified, leading to (a) characterization and classification of measurement techniques, (b) suggestions on the selection of appropriate measurement methods for different types of model constructs including individual-level, global, configural, and shared, and (c) discussion of the modeling implications of interactions between measurement, constructs, and causal paths. A multi-dimensional perspective is offered through combinations of different “measurement methods” and “measurement bases”. A Bayesian approach is also proposed to operationalize the multi-dimensional measurements. Examples are provided to help explain the roles of these measurements in capturing the relation between organizational factors and safety performance. This paper is a product of research which has the primary purpose of extending Probabilistic Risk Assessment (PRA) modeling frameworks to include the effects of organizational factors as the fundamental causes of accidents and incidents.     

Biodegradability of a polyacrylate superabsorbent in agricultural soil

Superabsorbent polymers (SAP) are used, inter alia, as soil amendment to increase the water holding capacity of soils. Biodegradability of soil conditioners has become a desired key characteristic to protect soil and groundwater resources. The present study characterized the biodegradability of one acrylate based SAP in four agricultural soils and at three temperatures. Mineralisation was measured as the ¹³CO₂ efflux from ¹³C-labelled SAP in soil incubations. The SAP was either single-labelled in the carboxyl C-atom or triple-labelled including additionally the two C-atoms interlinked in the SAP backbone. The dual labelling allowed estimating the degradation of the polyacrylate main chain. The ¹³CO₂ efflux from samples was measured using an automated system including wavelength-scanned cavity ring-down spectroscopy. Based on single-labelled SAP, the mean degradation after 24 weeks varied between 0.45 % in loamy sand and 0.82 % in loam. However, the differences between degradation rates in different soils were not significant due to a large intra-replicate variability. Similarly, mean degradation did not differ significantly between effective temperature regimes of 20° and 30 °C after 12 weeks. Results from the triple-labelled SAP were lower as compared to their single-labelled variant. Detailed results suggest that the polyacrylate main chain degraded in the soils, if at all, at rates of 0.12–0.24 % per 6 months.