Brain cancer cluster investigation around a factory emitting dichloromethane

Generation characteristics and spreading risk of VOCs released from a biological fermentation pharmaceutical factory

Pharmaceutical factories produce a large amount of volatile organic compounds (VOCs), which may pose a potential health threat to the environment, workers, and nearby residents. Sampling points were set up in the tylosin biological fermentation workshop (FW) and sewage treatment station (STS) of a pharmaceutical factory in a central city in northern China to collect VOCs and study their generation characteristics and diffusion. The results indicated that with the increase in fermentation time, VOC production decreased gradually, and the decline was rapid. The main VOCs produced by the FW are oxygen-containing organics and nitrogen-containing organics including 1-heptyladehyde (8.86 × 10² mg m^-3), 1-methyl-2-pyrrolidone (6.36 × 10² mg m^-3) and benzene (5.85 × 10² mg m^-3). The STS mainly produces nitrogen-containing organics and oxygen-containing organics including 1-methyl-2-pyrrolidone (3.38 × 10³ mg m^-3), diethyl amine (9.60 × 10² mg m^-3) and methyl ethyl ketone (2.98 × 10² mg m^-3). VOCs produced by biopharmaceutical factories can diffuse for a long distance in the atmosphere. The highest concentration of chlorinated organic compounds can spread to 11.43 kilometers in the horizontal direction and 3 kilometers in the vertical direction. Acetaldehyde, butyraldehyde, diethylamine, butyl acetate and methyl ethyl ketone are odorous gases detected in the FW and STS, respectively. Benzene, carbon tetrachloride and acetaldehyde are the main carcinogenic VOCs produced in the fermentation process of tylosin. The research elucidated production characteristics, diffusion and health risks of VOCs in the FW, which provided a reference for the control of VOCs.

Evaluation of the carcinogenicity of dichloromethane in rats, mice, hamsters and humans

Dichloromethane (DCM) is a high production volume chemical (>1000 t/a) mainly used as an industrial solvent. Carcinogenicity studies in rats, mice and hamsters have demonstrated a malignant tumor inducing potential of DCM only in the mouse (lung and liver) at 1000-4000 ppm whereas human data do not support a conclusion of cancer risk. Based on this, DCM has been classified as a cat. 2 carcinogen. Dose-dependent toxicokinetics of DCM suggest that DCM is a threshold carcinogen in mice, initiating carcinogenicity via the low affinity/high capacity GSTT1 pathway; a biotransformation pathway that becomes relevant only at high exposure concentrations. Rats and hamsters have very low activities of this DCM-metabolizing GST and humans have even lower activities of this enzyme. Based on the induction of specific tumors selectively in the mouse, the dose- and species-specific toxicokinetics in this species, and the absence of a malignant tumor response by DCM in rats and hamsters having a closer relationship to DCM toxicokinetics in humans and thus being a more relevant animal model, the current classification of DCM as human carcinogen cat. 2 remains appropriate.

Developing of N-(4-methylpyrimidine-2-yl)methacrylamide Langmuir-Blodgett thin film chemical sensor via quartz crystal microbalance technique

In the present work, the characterization and gas sensing properties of newly synthesized N-(4-methylpyrimidine-2-yl)methacrylamide (N-MPMA) monomer Langmuir-Blodgett (LB) thin films were investigated. The UV-visible spectroscopy, quartz crystal microbalance (QCM), and atomic force microscopy were utilized to characterize N-MPMA LB thin films. The surface behavior of N-MPMA monolayer was stable and allowed an effective transfer at a surface pressure of 14 mN/m. The mass change/unit area value of the N-MPMA LB thin film deposited quartz crystal surfaces was investigated. The amount of N-MPMA LB thin film deposited on the substrate for bilayer was calculated as 228.72 ng (86.31 ng/mm² ) and 12.5 Hz frequency shift was observed for each layer of the N-MPMA film. The kinetic responses of N-MPMA LB film against chloroform, dichloromethane, benzene, and toluene were measured via QCM system at room temperature. N-MPMA QCM sensor results displayed that chloroform has the largest frequency shifts compared with the other vapors used in the present work and these results can be illuminating in terms of physical properties of organic vapors.