RESUMO
In order to explore the influence of polycyclic aromatic hydrocarbons (PAHs) emissions by petrochemical enterprises on the surrounding environment, atmospheric deposition samples of the PAHs were collected in the industrial and residential areas adjacent to a petrochemical enterprise from March 2017 to February 2018. Deposition fluxes and the composition of PAHs were studied. The source of PAHs was analyzed by a positive matrix factor (PMF) model. The results showed that the deposition fluxes of Σ15 PAHs ranged from 549 ng·(m2·d)-1 to 18845 ng·(m2·d)-1, with an average of 2712 ng·(m2·d)-1. The flux of Σ15 PAHs in the industrial area was 1.36 times greater than that in the residential area. The deposition fluxes of PAHs in winter and spring were higher than those in summer and autumn. The deposition flux was highest in January in the industrial area and lowest in October in the residential area. Phe, BbF, and Fla were the dominant monomers. There was noticeable difference of monomers between the industrial area and the residential area in summer and autumn. The monomers, such as BbF, BkF, and BgP, in the residential area were higher than those in industrial area, and the proportion of 5, 6 rings was higher, which indicated that traffic contributed more to the residential area; 3 ring PAHs in industrial area had a higher proportion, which pointed out that their main source was petroleum volatilization. Based on the quantitative source analysis, the PAHs in atmospheric deposition were mainly from traffic emissions, petroleum volatilization, and coal combustion. Three sources of PAHs accounted for 45.7%, 18.4%, 35.9%, and 46.3%, 21.4%, and 32.3%, respectively, in the industrial area and the residential area in winter and spring. In summer and autumn, the contribution of traffic sources to the residential area was as high as 65.2%, and the proportion of the petroleum source to the industrial area increased to 35.5%. Due to high-altitude emissions and favorable diffusion conditions, the coal combustion contribution was significantly reduced.
RESUMO
Plant-soil carbon stable isotope characteristics of riparian herbaceous ecosystem were ana-lyzed by measuring the δ13C value of plant tissues from four typical riparian herbaceous plants, which were Cynodon dactylon, Trifolium repens, Festuca arundinacea and Imperata cylindrical, and that of soil organic carbon (SOC) from different vertical depths along Dongfeng Port River in Qingpu District, Shanghai. The result showed that T. repens and F. arundinacea were C3 plants while C. dactylon and I. cylindrical were C4 plants. There was no significant difference between the δ13C va-lue of stem and leaf, litter and root of the four herbaceous plants. The surface SOC δ13C value of C3 and C4 plants strips showed different trends with soil depth, which could be related to the background SOC δ13C value, soil carbon stable isotope fractionation effect and plant root distribution depth as well. Plant input was the main source of SOC and the δ13C composition of plant organisms had direct effect on the SOC δ13C value. The δ13C value of plant components were significantly correlated with the δ13C value of SOC. The SOC content and δ13C value were significantly correlated in the four herbaceous plants strips. The SOC content and δ13C value showed linear negative correlation in C3 plant strips and linear positive correlation in C4 plant strips.
Assuntos
Carbono , Ecossistema , Pradaria , Isótopos de Carbono , China , SoloRESUMO
OBJECTIVE: To study the prevalence of severe acute respiratory syndrome coronavirus (SARS-CoV) like virus in animals at a live animal market of Guanzhou in 2004 before and after culling of wild animal action taken by the local authority, in order to predict the re-emerging of SARS from animal originals in this region. METHODS: Animals at live animal market were sampled for rectal and throat swabs in triplicate. A single step realtime reverse transcription-polymerase chain reaction (RT-PCR) diagnostic kit was performed for screening SARS-CoV like virus, the manual nested RT- PCR and DNA sequencing were performed for confirmation. Only specimens which tested positive for both of the N and P genes by nested RT-PCR were scored as positive. RESULTS: In 31 animals sampled in January 5 2004 before culling of wild animals at Guangdong Province, including 20 cats (Felis catus), 5 red fox (Vulpes vulpes) and 6 Lesser rice field rats (Rattus losea), 8 (25.8%) animals were tested positive for SARS-CoV like virus by RT-PCR methods, of which 4 cats, 3 red fox and one Lesser rice field rats were included. However, two weeks after culling of animals and disinfection of the market were implemented, in 119 animals sampled in January 20 2004, including 6 rabbits (Oryctolagus cuniculus), 13 cats, 46 red jungle fowl (Gallus gallus), 13 spotbill duck (Anas platyrhynchos), 10 greylag goose (Anser anser), 31 Chinese francolin (Franclinus pintadeanus), only rectal swab from one greylag goose was tested positive for SARS-CoV like virus. Furthermore, in 102 animals that including 14 greylag gooses, 3 cats, 5 rabbits, 9 spotbill duck (Anaspoecilorhyncha), 2 Chinese francolin (Franclinus pintadeanus), 8 common pheasant (Phasianus colchicus), 6 pigeons, 9 Chinese muntjac (Muntiacus reevesi), 19 wild boar (Sus scrofa), 16 Lesser rice field rats, 5 dogs, 1 mink (Mustela vison), 3 goats, 2 green peafowl (Pavo muticus) sampled in April, May, June, July, August and November, only rectal swab from one pig was tested positive. However, of 12 and 10 palm civets sampled in November and December including five of which had been at the live animals market for 2 days, none of them was tested positive. CONCLUSION: This findings revealed that animals being sampled in April, May, June, July, August and November of 2004, only one rectal swab from a pig was tested positive as SARS-CoV like virus, much lower than the results from the previous year, suggesting that the possibility of re-emerging of human infection from animal origins is low for the winter of 2004-2005.
