Multi-biomarker approach in wild European bullhead, Cottus sp., exposed to agricultural and urban environmental pressures: practical recommendations for experimental design

In freshwater ecosystems, a large number of chemical substances are able to disturb homeostasis of fish by modulating one or more physiological functions including the immune system. The aim of this study was to assess multi-biomarker responses including immunotoxicity induced by urban and agricultural pressure in European bullheads living in a small French river basin. For this purpose, a set of biochemical, immunological, physiological and histological parameters was measured in wild bullheads from five locations characterized by various environmental pressures. Moreover, to address effects of physiological status and contamination level variation on biomarker responses, fish were sampled during three periods (April, July and October). Results revealed a clear impact of environmental pressure on fish health and particularly on immunological status. An increase of EROD activity was recorded between upstream and downstream sites. Upstream sites were also characterized by neurotoxicological effects. Fish exhibited upstream/downstream variations of immunological status but strong differences were observed according to sampling season. Conversely, regarding biochemical and immunological effects, no significant response of physiological indexes was recorded related to environmental pressures. According to these results, the European bullhead appears as a valuable model fish species to assess adverse effects in wildlife due to urban and agricultural pressures.     

210Pb deposition in the far East Asia: controlling factors of its spatial and temporal variations

In order to better understand the behavior of ²¹⁰Pb deposition in Far East Asia, comprehensive data of monthly ²¹⁰Pb deposition, which includes several time-series and spatial distribution data at 14 stations in Japan and 2 stations in Taiwan, were analyzed. Pb-210 deposition at most of the sites exhibited a typical seasonal change with higher values in winter and lower values in summer; especially, the greatest ²¹⁰Pb deposition in the world occurred in winter at sites beside the Japan Sea. The deposition behavior of ²¹⁰Pb in Far East Asia differed between winter and summer. The meteorological phenomenon peculiar to winter of the Japan Sea side, i.e., formation of the Japan Sea convergence zone, might cause the high ²¹⁰Pb concentration in rainwater, as may heavy snowfall. The ²¹⁰Pb concentration in rainwater showed long-term variability, although this differed between winter and summer. This long-term variability may be related to climatological factors such as El Niño.     

Revealing source signatures in ambient BTEX concentrations

Management of ambient concentrations of Volatile Organic Compounds (VOCs) is essential for maintaining low ozone levels in urban areas where its formation is under a VOC-limited regime. The significant decrease in traffic-induced VOC emissions in many developed countries resulted in relatively comparable shares of traffic and non-traffic VOC emissions in urban airsheds. A key step for urban air quality management is allocating ambient VOC concentrations to their pertinent sources. This study presents an approach that can aid in identifying sources that contribute to observed BTEX concentrations in areas characterized by low BTEX concentrations, where traditional source apportionment techniques are not useful. Analysis of seasonal and diurnal variations of ambient BTEX concentrations from two monitoring stations located in distinct areas reveal the possibility to identify source categories. Specifically, the varying oxidation rates of airborne BTEX compounds are used to allocate contributions of traffic emissions and evaporative sources to observed BTEX concentrations.     

Time stress,predation risk and diurnal–nocturnal foraging trade-offs in larval prey

Insect larvae increase in size with several orders of magnitude throughout development making them more conspicuous to visually hunting predators. This change in predation pressure is likely to impose selection on larval anti-predator behaviour and since the risk of detection is likely to decrease in darkness, the night may offer safer foraging opportunities to large individuals. However, forsaking day foraging reduces development rate and could be extra costly if prey are subjected to seasonal time stress. Here we test if size-dependent risk and time constraints on feeding affect the foraging–predation risk trade-off expressed by the use of the diurnal–nocturnal period. We exposed larvae of one seasonal and one non-seasonal butterfly to different levels of seasonal time stress and time for diurnal–nocturnal feeding by rearing them in two photoperiods. In both species, diurnal foraging ceased at large sizes while nocturnal foraging remained constant or increased, thus larvae showed ontogenetic shifts in behaviour. Short night lengths forced small individuals to take higher risks and forage more during daytime, postponing the shift to strict night foraging to later on in development. In the non-seasonal species, seasonal time stress had a small effect on development and the diurnal–nocturnal foraging mode. In contrast, in the seasonal species, time for pupation and the timing of the foraging shift were strongly affected. We argue that a large part of the observed variation in larval diurnal–nocturnal activity and resulting growth rates is explained by changes in the cost/benefit ratio of foraging mediated by size-dependent predation and time stress.     

Nitrated and parent PAHs in the surface water of Lake Taihu, China: Occurrence, distribution, source, and human health risk assessment

Nitrated polycyclic aromatic hydrocarbons (NPAHs) have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons (PAHs) and thus have received increasing attention in recent years. In this study, the occurrence, distribution, source, and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry, normal, and flood seasons of 2018. The ΣPAH concentrations ranged from 255 to 7298 ng/L and the ΣNPAH concentrations ranged from not-detected (ND) to 212 ng/L. Among the target analytes, 2-nitrofluorene (2-nFlu) was the predominant NPAH, with a detection frequency ranging from 85% to 90% and a maximum concentration of 56.2 ng/L. The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds. In terms of seasonal variation, the highest levels of the ΣNPAHs and ΣPAHs were in the dry season and flood season, respectively. Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion, whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion. The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model. The carcinogenic risk level of the targets ranged from 2.09 × 10^?7 to 5.75 × 10^?5 and some surface water samples posed a potential health risk.     

Seasonal variations, temperature dependence, and sources of size-resolved PM components in Nanjing, east China

Size-segregated ambient particulate matter (PM) samples were collected seasonally in suburban Nanjing of east China from 2016 to 2017 and chemically speciated. In both fine (< 2.1 µm, PM_2.1) and coarse (> 2.1 µm, PM_>2.1) PM, organic carbon (OC) accounted for the highest fractions (26.9% ± 10.9% and 23.1% ± 9.35%) of all measured species, and NO₃⁻ lead in average concentrations of water-soluble inorganic ions (WSIIs). The size distributions of measured components were parameterized using geometric mean diameter (GMD). GMD values of NO₃⁻, Cl⁻, OC, and PM for the whole size range varied from < 2.1 µm in winter to > 2.1 μm in warm seasons, which was due to the fact that the size distributions of semi-volatile components (e.g., NH₄NO₃, NH₄Cl, and OC) had a dependency on the ambient temperature. Unlike OC, elemental carbon (EC), and elements, NH₄⁺, NO₃⁻, and SO₄²⁻ exhibited an increase trend in GMD values with relative humidity, indicating that the hygroscopic growth might also play a role in driving seasonal changes of PM size distributions. Positive matrix factorization was performed using compositional data of fine and coarse particles, respectively. The secondary formation of inorganic salts contributing to the majority (> 70%) of fine PM and 20.2% ± 19.9% of speciated coarse PM. The remaining coarse PM content was attributed to a variety of dust sources. Considering that coarse and fine PM had comparable mass concentrations, more attention should be paid to local dust emissions in future air quality plans.     

Seasonal to sub-seasonal variations of the Asian Tropopause Aerosols Layer affected by the deep convection, surface pollutants and precipitation

The Asian Tropopause Aerosols Layer (ATAL) refers to an accumulation of aerosols in the upper troposphere and lower stratosphere during boreal summer over Asia, which has a fundamental impact on the monsoon system and climate change. In this study, we primarily analyze the seasonal to sub-seasonal variations of the ATAL and the factors potentially influencing those variations based on MERRA2 reanalysis. The ability of the reanalysis to reproduce the ATAL is well validated by CALIPSO observations from May to October 2016. The results reveal that the ATAL has a synchronous spatiotemporal pattern with the development and movement of the Asian Summer Monsoon. Significant enhancement of ATAL intensity is found during the prevailing monsoon period of July–August, with two maxima centered over South Asia and the Arabian Peninsula. Owing to the fluctuations of deep convection, the ATAL shows an episodic variation on a timescale of 7–12 days. Attribution analysis indicates that deep convection dominates the variability of the ATAL with a contribution of 62.7%, followed by a contribution of 36.6% from surface pollutants. The impact of precipitation is limited. The ATAL further shows a clear diurnal variation: the peak of ATAL intensity occurs from 17:30 to 23:30 local time (LT), when the deep convection becomes strongest; the minimum ATAL intensity occurs around 8:30 LT owing to the weakened deep convection and photochemical reactions in clouds. The aerosol components of the ATAL show different spatiotemporal patterns and imply that black carbon and organic carbon come mainly from India, whereas sulfate comes mainly from China during the prevailing monsoon period.     

Soil contamination with antibiotics in a typical peri-urban area in eastern China: Seasonal variation, risk assessment, and microbial responses

The prevalence and persistence of antibiotics in soils has become an emerging environmental issue and an increasing threat to soil security and global public health. The problem is more severe in areas undergoing rapid urbanization; however, the ecological risks of antibiotics, seasonal variability, and associated soil microbial responses in peri-urban soils have not been well-explored. The seasonal soil sampling campaigns were conducted in a typical peri-urban watershed in eastern China to investigate distribution of antibiotics. The results demonstrated higher mean concentrations of most antibiotic compounds in winter than in summer in peri-urban soils. The seasonal variations of norfloxacin, enrofloxacin, and ciprofloxacin were more significant than those of other antibiotics, due to their higher migration ability and bioavailability. An ecological risk assessment demonstrated that chlortetracycline, ciprofloxacin, doxycycline, and ofloxacin can pose high risks to soil microorganisms. Furthermore, the coexistence of multiple antibiotics obviously poses higher risks than individual compounds. A redundancy analysis demonstrated that tetracyclines mainly showed negative correlations with Firmicutes and Chloroflexi, and quinolones showed obviously negative correlations with Acidobacteria, Gemmatimonadetes, and Nitrospirae, suggesting potential inhibition from antibiotics on biological activities or biodegradation processes. However, the persistence of antibiotics in soil results in a significant decrease in bacterial diversity and a change in dominant species. Our results provide an overview of the seasonal variability of antibiotics and the associated effects on bacterial communities in peri-urban soils. The results can provide scientific guidance on decreasing soil contamination with antibiotics to enhance soil security in similar areas.     

PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in Beijing: Seasonal variations, sources, and risk assessment

Polycyclic aromatic hydrocarbons(PAHs) have been of health concern due to its carcinogenesis and mutagenesis. In this study, we aimed to assess the variations, sources, and lifetime excessive cancer risk(ECR) attributable to PAHs bound to ambient particulate matters with aerodynamic diameter less than 2.5 μm(PM_(2.5)) in metropolitan Beijing, China. We collected24-hour integrated PM_(2.5) samples on daily basis between November 2014 and June 2015 across both central heating(cold months) and non-heating(warm months) seasons, and further analyzed the PAH components in these daily PM_(2.5) samples. Our results showed that total concentrations of PM_(2.5)-bound PAHs varied between(88.6 ± 75.4) ng/m~3 in the cold months and(11.0 ± 5.9) ng/m~3 in the warm months. Benzo[a]pyrene(Ba P), the carcinogenic marker of PAHs,averaged at 5.7 and 0.4 ng/m~3 in the cold and warm months, respectively. Source apportionment analyses illustrated that gasoline, biomass burning, diesel, coal combustion and cooking were the major contributors, accounting for 12.9%, 17.8%, 24.7%, 24.3% and 6.4% of PM_(2.5)-bound PAHs, respectively. The BaP equivalent lifetime ECR from inhalation of PM_(2.5)-bound PAHs was 16.2 cases per million habitants. Our results suggested that ambient particulate reduction from energy reconstruction and adaption of clean fuels would result in reductions PM_(2.5)-bound PAHs and its associated cancer risks. However, as only particulate phased PAHs was analyzed in the present study, the concentration of ambient PAHs could be underestimated.     

季节调整分析在城市火灾发生规律研究中的应用

利用样本周期图法定量分析了城市火灾序列的周期性,并实例分析得出了北京市火灾时间序列具有12个月和48个月的周期性。然后采用季节调整法,将火灾时间序列中的季节因子和不规则因子提取出来,得出了经季节调整后的时间序列,从而得到了北京市火灾发生受季节因素影响的大小和城市火灾时间序列的基本发展趋势,大大提高了火灾数据之间的可比性。同时结论可为消防管理部门有针对性地采取消防监督管理措施和科学地安排消防执勤战备提供有力指导。