[Distribution Characteristics, Source Analysis and Ecological Risk Assessment of Heavy Metals in the Typical Industry Reclaimed Soil].

To further explore the characteristics of heavy metal pollution and the ecological risk of typical industries in reclaimed soil, based on data from 315 different depth profiles of soil samples collected from 49 plots in Jiading District, Shanghai, the geo-accumulation index and potential ecological risk index were used to evaluate the contents and potential ecological risk of seven heavy metals, namely Cd, Pb, Cu, Zn, Ni, Hg, and As. The APCS-MLR receptor model and PMF positive matrix factorization model were employed to analyze the pollution sources. The results showed that:① except for As, the contents of other heavy metals in the soil of the study area exceeded the Shanghai soil background values to varying degrees. The contents of Cd, Pb, Cu, Zn, Ni, and Hg in the surface soil were 3.54, 2.34, 2.91, 1.20, 3.75, and 4.40 times the background values, respectively. The contents of heavy metals in the soil decreased with the increase in depth, and heavy metals were enriched to a certain extent in the surface soil, indicating that human activities had an impact on the distribution of heavy metals in the soil. ② The APCS-MLR and PMF receptor models identified four main sources of soil heavy metals in the study area. Source 1 (Cu, Zn, and Pb) was a mixture of metal products and automobile manufacturing, source 2 (Ni and Cd) was electroplating enterprises, source 3 (Hg) was mainly from chemical enterprises, and source 4 (As) was natural. The combined use of the two receptor models further improved the accuracy and credibility of source identification. ③ The geo-accumulation index in descending order was Hg(1.54)>Ni(1.32)>Cd(1.21)>Cu(0.96)>Pb(0.64)>Zn(-0.33)>As(-1.02). The potential ecological risk index showed that the comprehensive potential ecological risk index RI value in the study area ranged from 32.50 to 4 910.97, with a mean of 321.40, indicating a strong potential ecological risk. The pollution values of heavy metals Hg, Ni, and Cd in industrial site soil deserve further attention for re-development and utilization purposes.

The ecology of bacterial communities in groundwater of industrial areas: Diversity, composition, network, and assembly.

Groundwater provides freshwater resources necessary for mankind, but its quality is significantly impacted by anthropologic activities. The unique characteristics of groundwater provide a special niche for bacterial colonization. To maintain the sustainability of groundwater ecosystem, a good understanding of the influencing factors and assembly mechanisms for bacterial communities is necessary. Here, we investigated the bacterial communities of groundwater from two industrial zones in Shanghai, a highly industrialized city, during the wet and dry seasons using the high-throughput sequencing technology. Our study uncovered the significant effects of season, geographical location, and industrial type on the diversity and composition of groundwater bacterial communities, particularly, we found that season was the most dominant factor with much stronger influences (give the explanation 17.7%) in comparison with geographical location (8.8%) and industrial type (7.5%). Co-occurrence networks revealed that geographical location explained more variations of bacterial ecological network than season did. Both distance-decay of similarities and variation partitioning analyses indicated that the assembly of groundwater bacterial communities was more governed by environmental filtering compared to spatial-related dispersal. Finally, null model analysis suggested the role of stochastic processes, including dispersal and drift, in shaping the groundwater bacterial communities cannot be ignored. These findings would benefit to improve our understanding of the bacterial communities in groundwater ecosystem and provide a theoretical foundation for groundwater health management.

Spatial and seasonal variation and sources of deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) in Shanghai.

Spatial and temporal variations of polycyclic aromatic hydrocarbons (PAHs) deposition fluxes and sources may significantly facilitate risk evaluation and pollution control of super megacity in China. A study on PAHs of wet and dry deposition in Shanghai was conducted from January to December of 2019. Seventeen sampling sites located in four functional areas were set, including the Baoshan iron and steel industry area (BS), Jinshan petrochemical industry area (JS), city center (CC), and Chongming agricultural area (CM). A total of 15 PAHs were determined by gas chromatography-mass spectrometry (GC-MS, Agilent 7890A/5975C). PAHs atmospheric deposition flux in winter was highest (3.12 ± 1.98 µg/(m2·day), mostly attributed to local emissions accumulation under adverse meteorological diffusion conditions, as well as pollutants transport from northern China during heating season. PAHs deposition fluxes in industrial area (BS and JS) were 3.75 ± 4.08 µg/(m2·day) and 3.18 ± 3.62 µg/(m2·day) respectively, which were greater than those in CC and CM, accounting for 1.91 ± 1.06 µg/(m2·day) and 1.41 ± 0.61 µg/(m2·day) respectively. Proportional composition and isomer ratios of PAHs indicated that the PAHs deposition in winter and spring samples were more homogeneous, whereas those of summer and autumn seemed to be more variable and dispersed. Positive matrix factorization model were employed to identify the potential sources of PAHs in specific functional areas. A dominance of contribution was attributed to coal combustion (46%) at BS, petroleum volatilization (48%) at JS, biomass burning (55%) at CM, and vehicle emission (49%) at CC. This study highlighted that local urbanization and industrialization have a significant contribution to PAHs deposition to specific functional regions in Shanghai.

Changes of bacterial community in arable soil after short-term application of fresh manures and organic fertilizer.

The application of animal manure is highly recommended in agricultural production. However, the effect of different kinds of manures on bacterial community in farmland still remains unclear. In this study, a short-term field experiment was conducted to investigate the rapid effects of pig manure (PM), chicken manure (CM) and organic fertilizer (OF, composted by pig manure) application on soil physicochemical properties and soil bacterial community. The results showed that the application of CM and OF significantly increased soil bacterial richness (p < 0.05), mainly correlated with the increase of soil total nitrogen. Compared with CM and PM, OF had the greatest disturbance to soil bacterial structure. And total phosphorus showed the highest correlation with bacterial community. Meanwhile, the application of OF reduced the relative abundance of Actinobacteria, the organic matter synthetic bacteria, and Nitrospirae, the nitrifying bacteria, by 17.18% and 40.00%, respectively. 16S functional prediction analysis results shows that the application of OF increased the relative abundance of genes encoding Ribulose-1,5-bisphosphate carboxylase/oxyg (RuBsiCO), the genes involved in soil Calvin cycling, by 20.51%, and increased the relative abundance of genes encoding nitrous-oxide reductase by 44.86%. In conclusion, Short-term application of OF had greater disturbance to soil bacteria than CM and PM, and it had a significant influence on soil functional bacteria and genes involved in soil carbon and nitrogen cycling.

Occurrence of heavy metals, antibiotics, and antibiotic resistance genes in different kinds of land-applied manure in China.

Various pollutants remaining in the livestock and poultry manures pose potential threat to the soil ecosystem during land application, whose impact should be appreciated. The occurrence of heavy metals, antibiotics, and antibiotic resistance genes (ARGs) in swine manure (SM), chicken manure (CM), and the SM organic fertilizer (OF) were investigated. The order of total concentrations of antibiotics detected in manures was as follows: SM > CM > OF. The amount of ciprofloxacin (CIP) in SM reached up to 6.61 mg/kg, which only occupied 1% of the antibiotic concentration reported in the past years. The total concentration of thirteen ARGs in CM ranked first, reaching 7.35 × 1011 copies/g, among which the strB gene was detected with the highest concentration. It was worth noting that the qnr ARGs were persistent in OF with the absence of corresponding antibiotics, indicating ARGs were harder to remove than antibiotics during manure composting. Zn and Cu (46.5-843 mg/kg) were obviously higher than other seven heavy metals, and significantly correlated with most ARGs (p < 0.01). This study provided the basic data of the pollution in animal manures that will be land-applied, illuminating the original source of potential risk in soil ecosystem.

[Distribution Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Atmospheric Deposition in Areas Adjacent to a Large Petrochemical Enterprise].

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.

Bacterial community response to petroleum contamination in brackish tidal marsh sediments in the Yangtze River Estuary, China.

The brackish tidal marsh in the Baimaosha area of the Yangtze River Estuary was severely contaminated by 400 tons of heavy crude petroleum from a tanker that sank in December 2012. The spill accident led to severe environmental damage owing to its high toxicity, persistence and wide distribution. Microbial communities play vital roles in petroleum degradation in marsh sediments. Therefore, taxonomic analysis, high-throughput sequencing and 16S rRNA functional prediction were used to analyze the structure and function of microbial communities among uncontaminated (CK), lightly polluted (LP), heavily polluted (HP), and treated (TD) sediments. The bacterial communities responded with increased richness and decreased diversity when exposed to petroleum contamination. The dominant class changed from Deltaproteobacteria to Gammaproteobacteria after petroleum contamination. The phylum Firmicutes increased dramatically in oil-enriched sediment by 75.78%, 346.19% and 267.26% in LP, HP and TD, respectively. One of the suspected oil-degrading genera, Dechloromonas, increased the most in oil-contaminated sediment, by 540.54%, 711.27% and 656.78% in LP, HP and TD, respectively. Spore protease, quinate dehydrogenase (quinone) and glutathione-independent formaldehyde dehydrogenase, three types of identified enzymes, increased enormously with the increasing petroleum concentration. In conclusion, petroleum contamination altered the community composition and microorganism structure, and promoted some bacteria to produce the corresponding degrading enzymes. Additionally, the suspected petroleum-degrading genera should be considered when restoring oil-contaminated sediment.

[Effects of Manure and Organic Fertilizer Application on Soil Microbial Community Diversity in Paddy Fields].

To investigate the effect of typical manure application on soil microbes in paddy fields, a field experiment on manure application in Chongming Island was carried out. The composition and variety of soil microorganisms in rice paddy fields were analyzed using high-throughput theory (CK), chicken manure (CM), pig manure (PM), and organic fertilizer (OF). The results showed that compared with CK, the application of organic manure increased soil organic matter (SOM), and the application of chicken manure significantly increased the soil ammonia nitrogen (NH4+-N) and total nitrogen (TN) contents (P<0.05). Soil microbial diversity in the PM group was significantly higher than that in the CK group (P<0.05), and the soil microbial community richness in the OF group was significantly higher than that in the CM group (P<0.05). pH, total phosphorus (TP), total nitrogen, and Pb were the important factors affecting the composition of soil microbial communities in paddy fields. The microbial community structure in the CM group was significantly different from those in the other three groups. Compared with CK, the OF group increased the relative abundance of Nitrospira, and the CM group significantly reduced the relative abundance of the denitrifying bacteria Ignavibacteriae (P<0.01) to 40.56%, but significantly increased the relative abundance of nitrifying bacteria Thauera(P<0.05) to 203.00%. The PM group significantly increased the relative abundance of ammoniated bacteria Armatimonadetes (P<0.05) to 57.51% and the anaerobic strain Anaerolinea to 102.00%. The application of chicken manure and pig manure significantly increased the relative abundance of pathogens Pseudomonas and Flavisolibacter (P<0.05), respectively, while the application of organic manure reduced the relative abundance of Flavisolibacter. Overall, the application of manure increased the abundance of bacteria involved in the nitrogen cycle of paddy soils and played a positive role in regulating the nitrogen balance in paddy soils. However, direct application of chicken manure and fresh pig manure increased the abundance of pathogenic bacteria, which had a certain degree of stress on the soil health in the paddy field.

[Comparison and Source Apportionment of PAHs Pollution of Runoff from Roads in Suburb and Urban Areas of Shanghai].

Rapid urbanization has driven surface runoff pollution in urban areas to a serious state. In particular, polycyclic aromatic hydrocarbons(PAHs)from road surface runoff has attracted wide attention. Two traffic roads in Shanghai (Caobao Road in an urban central area, and Jiajin Expressway in the suburbs) were identified as research objects. Runoff samples from these two traffic roads were collected for 7 rainfall events between 2007 and 2018. Then, the concentration characteristics and composition ratio of PAHs were analyzed. The differences in pollution sources of runoff PAHs from two types of traffic roads were identified based on characteristic ratio method and positive matrix factorization(PMF). The results showed that the geometric mean value (5539.2 ng·L-1) of 16 PAHs of runoff from Jiajin Expressway in the suburbs was 10 times greater than that from Caobao Road (548.1 ng·L-1), which was related to a higher truck traffic and a lower cleaning frequency on Jiajin Expressway. The benzo(a)pyrene(BaP)concentration on both roads exceeded the national emission standard, and the amount in the Jiajin Expressway was up to 21 times higher than the standard. There was no significant difference in the composition of PAHs of runoff between Caobao Road and Jiading Expressway, and 4-6 ring were dominant and responsible for 80% of total PAHs loads in both sites. Based on the analysis of the characteristic ratio method, the PAHs of runoff from Caobao Road mostly came from coal-fired sources and traffic sources, while that from Jiajin Expressway were mostly from fossil fuels, coal, and other traffic sources. Quantitative source analysis through PMF method showed that the primary sources of PAHs were gas and coal, accounting for 48.6%, followed by traffic emission sources (29.8%), and oil sources (21.7%). The contribution ratios of PAHs sources of runoff from Jiajin Expressway, sorted in descending order, are:traffic emission sources (38.5%), coal-fired sources (34.6%), oil sources (14.6%), and coking sources (12.6%). PAHs sources and contribution rates between urban and suburban roads are completely different. Gas and coal were the main sources of PAHs of runoff from Caobao Road, which was related to the high population density and relatively large gas consumption in the Xuhui District. Traffic emission was the main source of PAHs from surface runoff on Jiajin Expressway, which was related to the massive flow of coaches and trucks, and their higher PAHs emission compared to small cars. In addition, there are still coking sources of PAHs of runoff from Jiajin Expressway, which can be related to the massive industrial coal consumption in the Qingpu District.

Spartina alterniflora invasion affects soil carbon in a C3 plant-dominated tidal marsh.

The carbon cycle is significantly affected by Spartina alterniflora invasion through its impact on blue carbon in many salt marshes. To determine the impacts on soil organic carbon (SOC), we studied the vertical and horizontal distribution of SOC. And stable carbon isotopes were used to explore the impact of the age of S. alterniflora invasion on SOC in Chongming Dongtan wetland located in the Yangtze River estuary, China. The results showed that the SOC concentration was higher in the S. alterniflora community than that in the native Phragmites australis community. The age of invasion and the SOC concentration increased with increasing elevation, while the SOC concentration decreased with increasing soil depth. The δ13C value became less negative at greater depth, which was related to the contribution from 13C- enriched carbon sources after 3 years of invasion. After 7 and 10 years, the δ13C value became more negative at greater depth in both communities. S. alterniflora had a positive effect on the soil carbon pool, and its contribution was related to soil depth. In the low tidal marshes, the contribution of S. alterniflora was negatively correlated with soil depth, while it was positively correlated with soil depth in the high tidal marshes. The results from this study will contribute to improved understanding of future ecological consequences.