[On-line Measurement of Trace Elements in PM2.5 in Winter in Urban Taiyuan, China: Levels and Source Apportionment].

In order to better identify the sources of PM2.5 in Taiyuan, hourly concentrations of 13 trace elements (K, Ca, Ba, Cr, Mn, Fe, Cu, Ni, Zn, As, Se, Pb, and Sr) in PM2.5 were monitored at an urban site in Taiyuan from January 1 to 29, 2022. The pollution characteristics of trace elements were analyzed and sources were apportioned using positive matrix factorization (PMF). The results showed that the average concentration of 13 total trace elements was (3901.6±2611.2) ng·m-3, which accounted for (7.1±7.7)% of PM2.5. The three dominant elements were Fe[(1319.5±1003.5 ng·m-3)], Ca[(1181.0±1241.6 ng·m-3)], and K[(883.3±357.3 ng·m-3)]. The average concentrations of Cr(Ⅵ) (4.6 ng·m-3) and As (11.2 ng·m-3) exceeded the guideline values of the Chinese National Ambient Air Quality Standard (GB 3095-2012) and the World Health Organization. Fugitive dust, vehicle emissions, industry, stainless-steel production, biomass burning and waste incineration, residential coal combustion, and industrial coal combustion were identified by the PMF model, which accounted for 45.5%, 1.4%, 15.8%, 23.7%, 5.5%, and 8.1%, respectively, of the total elements.Compared with those during the stages of pollution development and dissipation, the contributions of industrial coal combustion, residential coal combustion, and biomass burning and waste incineration to the total elements during the pollution maintenance stage of the PM2.5 pollution episode increased significantly, contributing 11.8%, 7.1%, and 28.1%, respectively, of the total elements. These results could provide scientific references for the refined source apportionment of PM2.5 in other areas.

[Characteristics and Sources of Dissolved Heavy Metals in Summer Precipitation of Taiyuan City, China].

To investigate the characteristics and sources of dissolved heavy metals in precipitation of Taiyuan, 61 precipitation samples were collected using an automated dry and wet sampler from 2013 to 2015 during summertime. The concentrations of 12 dissolved heavy metals were detected using ICP-MS, and wet deposition fluxes and sources were analyzed. The results showed that the pH ranged from 4.34 to 7.95, with a volume-weighted mean of 5.37. The mean concentration of the dissolved heavy metals was 236.931 µg·L-1, with a range of 66.324 to 1029.212 µg·L-1. Zn and Fe were the major components, together accounting for 53.39% of the total concentrations. The wet deposition fluxes of the 12 dissolved heavy metals reached 1.735 mg·(m2·d)-1. The enrichment factors of Ba, Cu, Sr, Zn, As, Cd, and Pb were all in excess of 100, suggesting that these metals were seriously influenced by anthropogenic activities. Results from positive matrix factorization (PMF) indicated that steel smelting emissions, coal combustion, vehicle emissions, and crustal dusts were the major sources of heavy metals in the precipitation of Taiyuan City, with average contributions of 38.34%, 23.06%, 20.45%, and 18.15%, respectively. According to backward trajectory analysis, air masses from the southwest and southeast directions contributed the most to precipitation during summer in Taiyuan, with percentages of 38 and 35, respectively. The southern industrial areas located in the Yuncheng-Linfen-Jinzhong and Jincheng-Changzhi-Jinzhong regions should be paid more attention.

[Distribution Characteristics of Water-soluble Ions in Size-segregated Particulate Matters in Taiyuan].

The distributions of size-segregated particles (PM10) and water-soluble ions (WSIs) in Taiyuan were studied from July 2014 to April 2015 by TE-235 aerosol sampling and ion chromatography analyzing. As the results shown, the daily PM10 level was 173.7 µg·m-3, which exceeded the Grade Ⅱ limitation value in the Ambient Air Quality Standard (150 µg·m-3, GB 3095-2012). PM10 levels varied seasonally, and its were 199.1 and 194.2 µg·m-3 in winter and spring, respectively, which were much higher than those in summer. The PM10 size-segregated was bimodal distribution for the range of 0-0.95 and 3.0-7.2 µm. The concentration of WSIs was the highest in winter, followed by summer and spring. SO42-, NO3- and NH4+ were the main water soluble ions and accounted for 66% to 80% of the total WSIs. SO42-, K+, NH4+ and Cl- showed a unimodal distribution at <0.95 µm in all samples, while Ca2+ and Mg2+ showed a bimodal distribution at <0.95 µm and 3.0-7.2 µm. NO3- showed a unimodal size distribution at <0.95 µm in winter and spring, compared with a bimodal distribution at <0.95 µm and 3.0-7.2 µm in summer. By the correlation analysis, PM10 and WSIs decreased with the increase of wind speed in summer and winter other than in spring for the road-dust re-suspension by strong wind. Based on the ratio analysis of NO3-/SO42- and Mg2+/Ca2+, coal combustion was the main source of NO3- and SO42-, while Mg2+ and Ca2+ were mainly from the dust and coal combustion.

The complete mitochondrial genome sequence of Colossoma macropomum (Characiformes: Serrasalmidae).

Colossoma macropomum (Cuvier, 1816) is the largest characin of South America. This species and its congeners mainly feed on zooplankton, insects, snails and decaying plants. In this paper, we sequenced and annotated the complete mitogenome of C. macropomum. The total length is 16,703 bp, and it typically consist of 37 genes, including 13 protein-coding genes, two rRNAs, 22 tRNA, a light-strand replication origin (OL) and a large control region (D-loop). The overall base composition is 29.9%, 24.6%, 29.5% and 15.9% for A, T, C and G, respectively, with a slight bias on AT content (54.6%). All protein-coding genes share the start codon ATG, except for COI, which begins with GTG. Most of them have TAA or TAG as the stop codon, except COII, ND4 use AGA and COI, Cytb use an incomplete stop codon T. This information could provide useful molecular data and contribute to further phylogenetic studies of Characiformes and Serrasalmidae.

The complete mitochondrial genome sequence of Hemibagrus nemurus (Siluriformes: Bagridae).

Hemibagrus nemurus (Valenciennes, 1840) is a kind of tropical freshwater catfish which is native to Asian waters. It is economically valued for its importance in fisheries and aquaculture. At present, there exist some confusion in species identification in Bagridae. In this paper, we sequenced and characterize the complete mitogenome of H. nemurus. The genome was 16,526 bp in length, and typically consists of 37 genes, including 13 protein-coding genes, 2 rRNAs, 22 tRNA, 1 origin of replication on the light-strand (OL) and a single large control region (CR). The gene organization is identical to that of a typical bony fish. The overall base composition was 31.5%, 26.6%, 26.7%, and 15.2% for A, T, C, and G, respectively, with a slight bias on AT content (58.1%). This result is expected to provide useful molecular data and contribute to further taxonomic and phylogenetic studies of Hemibagrus and Bagridae.

The complete mitochondrial genome of Carposina sasakii (Lepidoptera: Carposinidae).

The peach fruit moth, Carposina sasakii belongs to Carposinidae in Lepidoptera. In this paper, we described the complete mitogenome of C. sasakii. It is 15,611 bp in length, including 13 PCGs, 2 rRNAs, 22 tRNAs and a major noncoding A + T-rich region, which revealed the typical gene content found in other metazoan mitogenomes. The overall base composition is 42.0% A, 39.5% T, 7.75% G and 10.75% C. The A + T-rich region is located between rrnS and trnM. There is a motif ATAGA in downstream of rrnS followed by a 19 bp Poly-T stretch. The Poly-A is not found in upstream of trnM, and the position of Poly-A is replaced by a stem-loop structure. There are eight mononucleotide repeat sequences (Tn/An) with the length of 7 bp-19bp, three dinucleotide repeat sequences (TA)n/(AT)n, and a longer repeat sequence (AATATATA)5 in A + T-rich region. The mononucleotide repeat sequences occur repeatedly in A + T-rich reigion of C. sasakii, which is special in insects sequenced of Lepidoptera.

[Chemical characteristics of 3-year atmospheric precipitation in summer, Taiyuan].

The chemical characteristics of the precipitation in Taiyuan in summer of 2011-2013 were investigated. The results showed that the pH of precipitation varied from 4.63 to 8.02 with a volume-weighted mean of 5.19. The frequency of acid rain was 37.0%, 31.2% and 17.4%, respectively, in 2011-2013. SO4(2-) and NO3(-) were dominant anions in the precipitation, which accounted for 67.2% and 22.0% of the total anions, respectively. While Ca2+ and NH4+ were dominant cations in the precipitation, which accounted for 55.1% and 29.0% of the total cations, respectively. There were evident declining trends in the concentration of SO4(2-), NO3-, Ca2+ and NH4+ in the precipitation over the study period. The mean ratio of SO4(2-) to NO3(-) in summer precipitation was 3.02, indicating that the acid rain was of sulfuric-nitrous mixed type, however, NO3- was very important for the acidity of rain water. Neutralization factors (NF) were calculated to show that Ca2+ and NH4+ were the predominant neutralizers in rainwater samples, but Mg2+ could also not be negligible. The correlation analysis revealed that coal combustion was the dominant source of chemical composition of rainwater in summer of Taiyuan. The back trajectory analysis demonstrated that the air pollutants of Taiyuan were from the local plants and the coal coking plants in the southern Taiyuan basin. However, to improve the air quality in this city, both industrial emissions from thermal power plants and coal coking plants in Taiyuan basin need to be controlled.

[Composition and variation characteristics of atmospheric carbonaceous species in PM 2.5 in Taiyuan, China].

Day-night variation characteristics of organic carbon (OC) and elemental carbon (EC) in atmospheric fine particles (PM2.5) collected during winter of 2009 and spring of 2010 in Taiyuan city were analyzed using DRI Model 2001A Thermal/Optical Carbon Analyzer, and the sources of carbonaceous materials in PM2.5 were analyzed. The results showed that the average concentrations of PM2.5, OC, EC and average OC/EC ratios were all higher during winter [(289.2 ± 104.8) µg x m(-3), (65.2 ± 22.1) µg x m(-3), (23.5 ± 8.2) µg x m(-3) and 2.8 ± 0.3] than during spring [(248.6 ± 68.6) µg x m(-3), (29.7 ± 6.2) µg x m(-3), (20.2 ± 5.4) µg x m(-3) and 1.5 ± 0.3], higher in nighttime [(309.3 ± 150.0) µg x m(-3), (74.6 ± 19.5) µg x m(-3), (24.3 ± 6.6) µg x m(-3) and 3.1 ± 0.3] than in daytime [(234.9 ± 122.1) µg x m(-3), (54.9 ± 28.2) µg x m(-3), (22.6 ± 10.8) µg x m(-3) and 2.5 ± 0. 5] during winter while higher in daytime [(292.5 ± 120.8) µg x m(-3), (32.7 ± 10.5) µg x m(-3), (22.7 ± 10.1) µg x m(-3) and 1.6 ± 0.5] than in nighttime [(212.3 ± 36.7) µg x m(-3), (29.6 ± 6.6) µg x m(-3), (20.7 ± 6.4) µg x m(-3) and 1.5 ± 0.2] during spring. This result was explained by the fact that winter is a "heating season", especially in nighttime, emission of carbonaceous particles was increased because of the increase of coal and biomass combustion and diffusion of pollutants was difficult because of low atmospheric temperature and stable atmospheric conditions; and high OC/EC was caused by increase of OC emission but not contribution of secondary organic carbon (SOC) since low temperature and weak solar radiation were not favorable for the formation of SOC. The higher concentrations of PM2.5, OC and EC in daytime than in nighttime during spring might be due to more dust in daytime because of higher wind speed and lower relative humidity in daytime than in nighttime, and the higher OC/EC in daytime than in nighttime might be caused by higher temperature and stronger solar radiation in daytime, which were favorable for the formation of SOC. Comparing with other cities in China, Taiyuan showed high concentrations of PM2.5, OC and EC, indicating serious carbonaceous aerosol pollution which may significantly contribute to the formation of dust-haze.

[Contamination characteristics of short-chain chlorinated paraffins in edible fish of Shanghai].

According to the local habit of eating fish, in a total of 68 samples, 8 kinds of different trophic levels of edible fish collected in Shanghai were determined in terms of concentration and distribution profile of short chain chlorinated paraffin (SCCPs) in muscles to investigate the pollution status of SCCPs in edible fish from the Yangtze River Delta region. The results indicated that the concentrations (dw) of SCCPs in edible fish were in the range of 36-801 ng x g(-1). With the increase in carbon chain length, the concentration of SCCPs decreased. In addition, lower chlorinated (Cl6-Cl8) and shorter chain (Cl10, C11) congeners were the dominant chlorine and carbon homologues groups, respectively, contributing a total relative abundance of 61.46%-82.50% to the total abundance of SCCPs. The levels of SCCPs in fish of Shanghai were in the medium level worldwide, and the distribution pattern was in line with those of the domestic and foreign studies.

[Emission and source characterization of monoaromatic hydrocarbons from coke production].

Monoaromatic hydrocarbons (MAHs) from indigenous and industrial coking processes are studied in Shanxi province. They are sampled on the top of coke ovens and in the chimneys using stainless steel canister and determined by GC/MSD after preconcentration with liquid nitrogen. Benzene, toluene and xylene are the main components among MAHs emitted from coking processes. Benzene and the total MAHs concentrations were as high as 3421.0 microg/m3 and 4 865.9 microg/m3 in the air from indigenous coking, 548.7 microg/m3 and 1 054.8 microg/m3 in the oventop air from industrial coking, and 1 376.4 microg/m3 and 1 819.4 microg/m3 in stack gas from industrial coking, respectively. The MAHs concentrations vary greatly during the indigenous coking process, which in the prophase (from firing to 10 days) is obviously higher than in the anaphase (10 days to quenching the coke). In industrial coking the MAHs in the oventop air are highest when charging the coal and next when transferring the hot coke, but in stack gas they are highest when charging coal and lowest when transferring the coke. Benzene, toluene, ethylbenzene and xylene (BTEX) in industrial coking samples show good linearity, indicating that MAHs in industrial coking might come predominantly from coal pyrolysis; but BTEX distribute dispersedly in indigenous coking samples, indicating that its emission might be affected by many factors. In all samples BTEX ratios especially high B/E ratio, is unique among MAHs sources, and might be helpful to characterize pollution from coking.