Contribution of precursor compounds to the release of per- and polyfluoroalkyl substances (PFASs) from waste water treatment plants (WWTPs)

Per-and polyfluoroalkyl substances(PFASs) are ubiquitous in sludge and water from waste water treatment plants, as a result of their incorporation in everyday products and industrial processes. In this study, we measured several classes of persistent PFASs,precursors, transformation intermediates, and newly identified PFASs in influent and effluent sewage water and sludge from three municipal waste water treatment plants in Sweden, sampled in 2015. For sludge, samples from 2012 and 2014 were analyzed as well.Levels of precursors in sludge exceeded those of perfluoroalkyl acids and sulfonic acids(PFCAs and PFSAs), in 2015 the sum of polyfluoroalkyl phosphoric acid esters(PAPs) were 15–20 ng/g dry weight, the sum of fluorotelomer sulfonic acids(FTSAs) was 0.8–1.3 ng/g,and the sum of perfluorooctane sulfonamides and ethanols ranged from non-detected to 3.2 ng/g. Persistent PFSAs and PFCAs were detected at 1.9–3.9 ng/g and 2.4–7.3 ng/g dry weight, respectively. The influence of precursor compounds was further demonstrated by an observed substantial increase for a majority of the persistent PFCAs and PFSAs in water after waste water treatment. Perfluorohexanoic acid(PFHxA), perfluorooctanoic acid(PFOA), perfluorohexane sulfonic acid(PFHxS), and perfluorooctane sulfonic acid(PFOS)had a net mass increase in all WWTPs, with mean values of 83%, 28%, 37% and 58%,respectively. The load of precursors and intermediates in influent water and sludge combined with net mass increase support the hypothesis that degradation of precursor compounds is a significant contributor to PFAS contamination in the environment.     

Removal of humic substances by biosorption

Fungal pellets of Aspergillus niger 405,Aspergillus ustus 326,and Stachybotrys sp.1103 were used for the removal of humic substances from aqueous solutions.Batchwise biosorption,carried out at pH 6 and 25°C,was monitored spectrophotometrically and the process described with Freundlich’s model.Calculated sorption coeffcients Kf and n showed that A.niger exhibited the highest effciency.A good match between the model and experimental data and a high correlation coeffcient(R2)pointed out to judicious choice of ...     

Transport and fate of mercury under different hydrologic regimes in polluted stream in mining area

Seepage from Hg mine wastes and calcines contains high concentrations of mercury (Hg). Hg pollution is a major environmental problem in areas with abandoned mercury mines and retorting units. This study evaluates factors, especially the hydrological and sedimentary variables, governing temporal and spatial variation in levels and state of mercury in streams impacted by Hg contaminated runo . Samples were taken during di erent flow regimes in theWanshan Hg mining area in Guizhou Province, China. In its headwaters the sampled streams/rivers pass by several mine wastes and calcines with high concentration of Hg. Seepage causes serious Hg contamination to the downstream area. Concentrations of Hg in water samples showed significant seasonal variations. Periods of higher flow showed high concentrations of total Hg (THg) in water due to more particles being re-suspended and transported. The concentrations of major anions (e.g., Cl??, F??, NO3?? and SO4 2??) were lower during higher flow due to dilution. Due to both sedimentation of particles and dilution from tributaries the concentration of THg decreased from 2100 ng/L to background levels (< 50 ng/L) within 10 km distance downstream. Sedimentation is the main reason for the fast decrease of the concentration, it accounts for 69% and 60% for higher flow and lower flow regimes respectively in the upper part of the stream. Speciation calculation of the dissolved Hg fraction (DHg) (using Visual MINTEQ) showed that Hg(OH)2 associated with dissolved organic matter is the main form of Hg in dissolved phase in surface waters in Wanshan (over 95%).     

基于仿生防护技术的海底管线悬空治理研究

针对海底管线悬空对海洋油气田安全生产的严重威胁及其对海洋环境构成的重大隐患,文章以海底管线周围的局部冲刷及其冲刷防护与控制技术为研究对象,从海底管线冲刷机理入手,分析了管线一次悬空和二次悬空的原因,从模型实验和工程实践两方面开展仿生防护技术治理海底管线悬空研究,利用高分子材料仿生草叶片的柔性黏滞阻尼作用,减缓流速,降低水流的携沙能力,最终达到固沙、填沙、保护管线的目的。     

Heart rate variability and motion sickness during forklift simulator driving

The goal of the study was to determine the effect of a 1-h hour long forklift truck virtual simulator driving on the mechanism of autonomic heart rate (HR) regulation in operators. The participants were divided into 2 subgroups: subjects with no definite inclination to motion sickness (group A) and subjects with a definite inclination to motion sickness (group B). Holter monitoring of electrocardiogram (ECG) signal was carried out in all subjects during the virtual simulator driving. For 12 consecutive epochs of ECG signal, HR variability analysis was conducted in time and frequency domains. In subjects with a definite inclination to motion sickness after ~30 min of the driving, changes in parameter values were found indicating an increase in sympathetic and parasympathetic activity with parasympathetic dominance.     

Evaluation of sound exposure and risk of hearing impairment in orchestral musicians

This study aimed to assess exposure to sound and the risk of noise-induced hearing loss (NIHL) in orchestral musicians. Sound pressure level was measured in 1 opera and 3 symphony orchestras; questionnaires were filled in. On the basis of that data, the risk of NIHL was assessed according to Standard No. ISO 1999:1990. Classical orchestral musicians are usually exposed to sound at equivalent continuous A-weighted sound pressure levels of 81?90 dB (10th?90th percentiles), for 20?45 h (10th?90th percentiles) per week. Occupational exposure to such sound levels over 40 years of employment might cause hearing loss (expressed as a mean hearing threshold level at 2, 3, 4 kHz exceeding 35 dB) of up to 26%. Playing the horn, trumpet, tuba and percussion carries the highest risk (over 20%).     

Twenty years of stream restoration in Finland: little response by benthic macroinvertebrate communities

The primary focus of many in-stream restoration projects is to enhance habitat diversity for salmonid fishes, yet the lack of properly designed monitoring studies, particularly ones with pre-restoration data, limits any attempts to assess whether restoration has succeeded in improving salmonid habitat. Even less is known about the impacts of fisheries-related restoration on other, non-target biota. We examined how restoration aiming at the enhancement of juvenile brown trout (Salmo trutta L.) affects benthic macroinvertebrates, using two separate data sets: (1) a before-after-control-impact (BACI) design with three years before and three after restoration in differently restored and control reaches of six streams; and (2) a space-time substitution design including channelized, restored, and near-natural streams with an almost 20-year perspective on the recovery of invertebrate communities. In the BACI design, total macroinvertebrate density differed significantly from before to after restoration. Following restoration, densities decreased in all treatments, but less so in the controls than in restored sections. Taxonomic richness also decreased from before to after restoration, but this happened similarly in all treatments. In the long-term comparative study, macroinvertebrate species richness showed no difference between the channel types. Community composition differed significantly between the restored and natural streams, but not between restored and channelized streams. Overall, the in-stream restoration measures used increased stream habitat diversity but did not enhance benthic biodiversity. While many macroinvertebrates may be dispersal limited, our study sites should not have been too distant to reach within almost two decades. A key explanation for the weak responses by macroinvertebrate communities may have been historical. When Fennoscandian streams were channelized for log floating, the loss of habitat heterogeneity was only partial. Therefore, habitat may not have been limiting the macroinvertebrate communities to begin with. Stream restoration to support trout fisheries has strong public acceptance in Finland and will likely continue to increase in the near future. Therefore, more effort should be placed on assessing restoration success from a biodiversity perspective using multiple organism groups in both stream and riparian ecosystems.     

白洋淀地区的多氯联苯污染研究

对白洋淀地区不同类型纸厂排水口底泥及保定市排污渠底泥进行了ＧＣ／ＥＣＤ分析，可萃取有机氯（ＥＯＣｌ）含量测定，检出了多氯联苯和有机氯农药。用截止分子量为１０００道尔顿的透析袋方法对相应地区的水体进行了检测，发现水体中可检出含氯农药六六六，但多氯联苯等由于水中存在浓度低未能检出，同样样品的ＧＣ／ＭＳ／ＣＯＭ结果表明，水体中主要存在的亲脂性有机污染物为：蒽酮、蒽二酮、苯胺、氯代烃、邻苯二甲酸酯类和苯系物。     

One-step preparation of a novel graphitic biochar/Cu0/Fe3O4 composite using CO2-ambiance pyrolysis to activate peroxydisulfate for dye degradation

Herein,a one-step co-pyrolysis protocol was adopted for the first time to prepare a novel pyrogenic carbon-Cu⁰/Fe₃O₄ heteroatoms (FCBC) in CO₂ ambiance to discern the roles of each component in PDS activation.During co-pyrolysis,CO₂ catalyzed formation of reducing gases by biomass which facilitated reductive transformation of Fe³⁺ and Cu²⁺ to Cu⁰ and Fe₃O₄,respectively.According to the a...     

Spatial factors affecting statistical power in testing marine fauna displacement

Impacts of offshore wind farms on marine fauna are largely unknown. Therefore, one commonly adheres to the precautionary principle, which states that one shall take action to avoid potentially damaging impacts on marine ecosystems, even when full scientific certainty is lacking. We implement this principle by means of a statistical power analysis including spatial factors. Implementation is based on geostatistical simulations, accommodating for zero-inflation in species data. We investigate scenarios in which an impact assessment still has to be carried out. Our results show that the environmental conditions at the time of the survey is the most influential factor on power. This is followed by survey effort and species abundance in the reference situation. Spatial dependence in species numbers at local scales affects power, but its effect is smaller for the scenarios investigated. Our findings can be used to improve effectiveness of the economical investment for monitoring surveys. In addition, unnecessary extra survey effort, and related costs, can be avoided when spatial dependence in species abundance is present and no improvement on power is achieved.