Poly- and perfluorinated compounds in household consumer products

Several household consumer products were analyzed for their content of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and fluorotelomer alcohols (FTOH) by nanoflow ultra performance liquid chromatography – mass spectrometry and gas chromatography – mass spectrometry. Among the investigated products, which are applied as sprays, were impregnating agents, cleaning agents, lubricants, and conditioners. In 14 of the 26 products analyzed, at least one polyfluorinated compound (PFC) was detected in 14 samples. 8?:?2 FTOH was the dominating PFC with concentrations up to 149?µg?mL^?1. The maximum concentration of PFOA was 14.5?µg?mL^?1, whereas PFOS was not detected in any sample. Investigated PFCs were mostly found in impregnating agents and lubricants, but were not detected in cleaning agents and conditioners. In FTOH-containing impregnating agents, similar ratios between 6?:?2 FTOH, 8?:?2 FTOH, and 10?:?2 FTOH were found. FTOH proportions in PFC-containing lubricants were similar as well. Total human exposure to PFC from consumer product aerosols for three different scenarios was estimated to be between 42.8 and 464?ng?kg^?1?per day.     

全球粮食危机：原因何在？ 出路何在？

当前,高涨的粮食价格已经造成了全球粮食危机,全球贫困人口无法获得粮食供应。解决粮食危机,关键是要根本改变世界农业发展方向。以往,人们以为通过向大自然不断索取,就可以提高食物产量。为了消灭所 有昆虫,或为了耕种,人们在土地上施用大量农药,最终使土地变成“工厂”。而不再是食物生产地。农业产业化确实能够在几年内增加农作物产量,收成显著。     

Partitioning of fluorotelomer alcohols (FTOH) to semipermeable membrane devices (SPMD)

Background, aim, and scope  

Fluorotelomer alcohols (FTOH) are widely used substances that were detected even in remote regions of the world. For the determination of FTOH in the atmosphere, appropriate sampling techniques are needed. In this study, triolein-filled low-density polyethylene tubes were used as semipermeable membrane devices (SPMD) and tested for their suitability as passive air samplers for FTOH.     

Re-evaluation of the conformational structure of sulfadiazine species using NMR and ab initio DFT studies and its implication on sorption and degradation

In the environment, the sorption and the degradation of organic pollutants are of increasing interest. The investigation of the chemical structures provides a basis for the development of a suitable binding model approach and for the mechanistic understanding of the chemical fate processes. The aim of this study was the identification of different species of the antibiotic compound sulfadiazine (SDZ) using (1)H and (13)C NMR experiments and ab initio density functional theory (DFT) calculations. In the neutral, aprotic solvent dimethylsulfoxide-d(6) (DMSO-d(6)), a new sulfadiazine structure containing an O-H-N hydrogen bond was identified. In the protic solvent water-d(2) and in dependence on pH and the position of the amidogen hydrogen atom nine possible SDZ conformations were analyzed and five structures were identified. Good conformity between theory and calculation of (1)H NMR was observed. Unfortunately, (13)C NMR is not sensitive enough for comparison and differentiation. In order to verify the identified structures, additional NBO/NLMO (natural localized molecular orbital) analyses were conducted (calculation of net atomic charges, bond polarity, atomic valence, and electron delocalization). Finally, conformation optimizations were performed in order to investigate the stability of the SDZ species. We showed that SDZ contains no S=O double bond, but that it has two S-O single bonds. Surprisingly, negative charges were observed at the pyrimidine nitrogen atom. With these results, the known structure of SDZ was revised. Studies of the geometrical structure and the torsion angles showed that SDZ is very flexible and can be easily fitted to the sorbent. These observations would explain the strong sorbance and hence the rapid formation of non-extractable residues in the environment because SDZ acts as a strong ligand. These results show that that the sulfonamide hydrogen is important for the biological activity but the pyrimidine nitrogen and the sulfonamide oxygen is responsible for the sorbance in environment.     

The war on deciduous forest: Large-scale herbicide treatment in the Swedish boreal forest 1948 to 1984

At the mid-twentieth century the pace of the transformation of the Swedish forest increased. New methods; large-scale clearcutting, mechanization of logging and planting of seedlings were developed. Chemicals were used to control insects and unwanted tree species. The aims of this study were to elucidate the timing, chain of events and the spatial extent of the large-scale spraying of phenoxy acids in Swedish forests and the drivers for this practice. More than 700 000 hectares of productive forest land was sprayed and the main driving force was a strong will to transform the forest into high-yield coniferous forest plantations. We conclude that; (1) the use of herbicides in forestry in Sweden was done on a very large scale in the period 1948–1984, (2) the ecosystem legacy of herbicide spraying must be investigated and (3) a homogenous cadre of like-minded professionals working across commercial companies, state agencies and universities is dangerous.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01660-5.