[Occurrence Characteristics and Risk Assessment of Microplastics in Water and Sediments of Anhui Section of Huaihe River Basin].

The occurrence characteristics and ecological risk level of microplastics in the water and sediments of the Anhui section of Huaihe River Basin were analyzed via field sampling, stereomicroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), risk index (H), and pollution load index (PLI) model. The current situation of microplastics in the water and sediments of the basin was analyzed, and the ecological risk assessment of microplastics was conducted. The results showed that the detection rate of microplastics at each site in the basin was 100%. The average abundance of microplastics in surface water and sediments was (39800±3367) n·m-3 and (5078±447) n·kg-1, respectively. The average abundance of microplastics in the downstream was higher than that in the upstream and midstream. The particle size of microplastics in water and sediments was primarily 20-150 µm, accounting for 82.96% and 80.77%, respectively. The microplastics were primarily fiber (water 76.05%, sediment 84.53%), film (water 21.83%, sediment 15.43%), and debris (water 2.12%, sediment 0.04%). The microplastics in water and sediments were primarily transparent, accounting for 63.31% and 83.69%, respectively. Polyethylene (65.74% in water and 80.62% in sediment) and polypropylene (18.43% in water and 9.71% in sediment) were the major components of water and sediments. Microplastics were primarily derived from agricultural films, abandoned fishing gear and nets, and artificially abandoned plastic bags in ports. The microplastic risk index (H) model assessment revealed that the risk index of some sites was high, and the risk level of microplastics in the Anhui section of Huaihe River Basin was grade II. The pollution load index (PLI) model assessment revealed that the ecological risk of surface water and sediments in the basin was generally low.

Rotifer distribution patterns in relation to dissolved organic matter in the middle reaches of Huai River Basin during the dry season.

Increased dissolved organic matter (DOM) may induce water browning and affect zooplankton communities by changing photochemical environment, microbial food web, and bioavailability of organic carbon supply. However, little is known about the relationship between DOM components and rotifers in natural rivers, relative to the cladocerans and copepods. Here, we investigated the spatial patterns of rotifer distribution in relation to DOM by collecting forty-four water samples from four areas in the middle reaches of Huai River Basin. Results revealed that DOM was described by two humic-like and two protein-like components. There were significant differences in the composition and diversity of rotifer communities among areas, which might be related to autochthonous and allochthonous DOM as well as geographical distances. Specifically, rotifer communities were mainly related to molecular weight, substituents on the aromatic ring, humification level, and protein-like materials. Autochthonous and fresh DOM was positively associated with rotifer abundance and richness, and terrigenous humic-like substances were positively associated with rotifer diversity and evenness. There was a reciprocal effect between rotifer and DOM. Our findings will contribute to the understanding of the possible effects of water browning on rotifer communities, providing new insights into the key role of DOM and rotifer in the energy transfer of aquatic systems.

Public health engagement: new opportunities and challenges in 60 years of China's health aid to Africa.

Along with China's active engagement in global affairs over the past decade, China's public health engagement (CPHE) has become an essential element of China's 60th anniversary of health aid and cooperation with Africa. Through analysis, we found that CPHE in Africa reflects a new shift in the content and form of China's foreign health aid. Compared with China's medical teams which only involve bilateral cooperation, CPHE has a number of substantive characteristics, mainly including the construction of public health infrastructure, malaria control, participation in public health emergencies and the provision of global public goods. This complexity necessitates that CPHE be implemented in a different form from China's medical teams, by adopting inclusive multiparty cooperation involving African and international partners. However, CPHE in Africa still faces a number of challenges in its practices. In particular, these challenges arise from the cross-cultural practice process, the African sociocultural context, the experience of public health and its participants. While the reasons for these challenges are diverse, this study argues that the main reason is the lack of multidisciplinary engagement in the Africanisation of the Chinese experience that corresponds to cross-cultural practice. On the Chinese side, a systematic strategy is needed to critically refine these challenges.

HIV-Related Knowledge and Sexual Behaviors among Teenagers: Implications for Public Health Interventions.

Background: Teenagers are at a turning point in people's physical and psychological maturity and are also in a critical period in reproductive and sexual health. It is reported that the initial age at first sexual behavior is younger than decades ago, which implies that the risky sexual behavior among teenagers may be on the rise. However, it is unclear about the changes of sexual knowledge and behaviors in recent years. Methods: Based on the national sentinel surveillance survey in 2011-2021 among students in Hangzhou, we selected out teenagers aged 10-19 years as our study sample. Demographic characteristics (gender, age, marital status, etc.), knowledge of HIV and sexual behaviors were collected. The sexual knowledge score and sexual behaviors were analyzed, and their influencing factors were explored. Results: In total, 1355 teenagers were incorporated in this study; the awareness rates of sexual knowledge in 2011, 2013, 2014 and 2021 were 74.9%, 71.8%, 89.3% and 95.8%, respectively, which showed an overall upward trend. The results of binary logistic regression showed that the survey year, whether students had received and participated in HIV-related publicity services and whether they had sexual behaviors, had a significant influence on whether the awareness rate ≥ 75%. The survey year and whether the awareness rate ≥ 75% had a significant influence on whether students had sexual behaviors. Conclusions: Both the average scores and awareness rates of teenagers' sexual knowledge showed an overall upward trend from 2011 to 2021. Teenagers' initial sexual behavior was at a low age, and the proportion of teenagers who had fixed, temporary and commercial heterosexual sex was still relatively high despite no significant increasing. Therefore, we should further strengthen health education on the risks of sexual behaviors from schools, families and health-related institutions to ensure teenagers receive HIV-related publicity services.

The spectral resolution of DOM in urban rivers affected by different non-point source intensities using self-organizing maps.

UV-Vis, three-dimensional excitation-emission matrix fluorescence spectroscopy (EEMs) and a self-organizing map (SOM) were used to study changes in the composition and constituent concentrations of dissolved organic matter (DOM) in the water column of two urban rivers with different non-point source inputs during spring and summer. The level of humification and the relative molecular mass of DOM were remarkably higher in the summer than in the spring (P < 0.01) in both rivers. The SOM model showed that the fluorescence intensity of the spring component was lower than in summer in water bodies with higher levels of non-point source inputs, while the opposite was true for water bodies with lower levels of non-point source inputs. Principal component analysis (PCA) showed that nutrients like nitrogen and phosphorus promoted autogenous processes in these water bodies. Seasonal variations and differing intensities of non-point source inputs had remarkable effects on urban river waters (R2 = 0.775, P < 0.001). Non-point source inputs increased the concentrations of humus-like fractions and promoted autogenesis in the water bodies.

Factors Associated With Delayed and Late Initiation of Antiretroviral Therapy Among Patients With HIV in Beijing, China, 2010-2020.

Objectives: To determine factors associated with late and delayed antiretroviral therapy (ART) initiation in China and provide evidence for HIV prevention. Methods: Logistics regression model was used to determine factors associated with three outcomes: late (CD4 cell count <200 cells/µL or clinical AIDS diagnosis prior to ART initiation), delayed (more than 1 month between HIV diagnosis date and ART initiation) and either late or delayed ART initiation. Results: Multivariable analysis revealed that male, heterosexual, HIV diagnosis before 2014, HBV/HCV seropositive, and tuberculosis were associated with increased odds of all three outcomes. Conversely, married or cohabiting patients were less likely to have delayed ART initiation and either late or delayed ART initiation, while people who inject drugs were more likely to have these two outcomes. Additionally, older age was associated with an increased risk of having either late or delayed ART initiation, but a decreased risk of delayed ART initiation. Conclusion: The proportion of late and delayed ART initiation decreased significantly after the release of the 2016 guidelines in China. To further improve late diagnosis and early treatment, precise interventions for key populations are required.

Migration experiences and reported commercial and non-commercial sexual behaviors among newly diagnosed HIV infections in China: a cross-sectional study.

BACKGROUND: Migration is known to influence human health. China has a high migration rate and a significant number of people who are HIV-positive, but little is known about how these factors intersect in sexual risk behaviors. OBJECTIVE: This study aimed to explore sexual risk behaviors between migrants and non-migrants among newly diagnosed HIV infections, and assess the changes of sexual risk behaviors with length of stay in the current city of migrants. METHODS: A cross-sectional questionnaire was conducted among people newly diagnosed with HIV from July 2018 to December 2020 who lived in Zhejiang Province. In the study, sexual risk behaviors included having multiple sexual partners and unprotected sexual behaviors (in commercial sexual behaviors, non-commercial sexual behaviors, heterosexual behaviors, and homosexual behaviors). Binary logistic regression models were employed to explore the influencing factors of sexual risk behaviors, measured by multiple sexual partners and unprotected sexual partners. RESULTS: A total of 836 people newly diagnosed with HIV/AIDS were incorporated in the study and 65.31% (546) were migrants. The percentages of non-commercial sexual behaviors among migrants were statistically higher than those of non-migrants. Commercial heterosexual behavior was higher among non-migrants compared with migrants. The proportion of study participants having unprotected sexual behaviors and multiple sexual partners with commercial/non-commercial partners was both higher among migrants compared with non-migrants. Among migrants, the likelihood of sexual risk behaviors in both commercial and non-commercial sex increased in the first 3 years and reduced after 10 years. Compared with non-migrants, migrants were statistically associated with multiple sexual partners [P = .007, odds ratio (OR) = 1.942]. However, migrants did not exhibit a significant difference in unprotected sexual behaviors compared with non-migrants. In addition, migrants aged between 18 and 45 years who relocated to the current city in the past 2-3 years tended to have multiple sexual partners (P < .05). CONCLUSIONS: People newly diagnosed with HIV engaged in different sexual risk behaviors among migrants and non-migrants and more attention should be paid to migrants. For non-migrants, it is urgent to promote the prevention of commercial sexual behaviors. For migrants, prevention of non-commercial sexual behaviors and universal access to health care especially for new arrivals who migrated to the current city for 2-3 years are needed. Moreover, sexual health education and early HIV diagnosis are necessary for the entire population.

A self-organizing map approach to the analysis of lake DOM fluorescence for differentiation of organic matter sources.

The sources and properties of dissolved organic matter (DOM) in two lakes with different non-point source inputs were investigated by combining conventional three-dimensional fluorescence spectroscopy methods with a self-organizing map (SOM). To assess the DOM humification level, the representative neurons 1, 11, 25, and 36 were assessed. The SOM model showed that the DOM humification level of the Gaotang Lake (GT) which has a mainly agricultural non-point source input was significantly higher than that of the Yaogao Reservoir (YG) which has a mainly terrestrial source input (P < 0.01). The GT DOM mainly came from factors such as agricultural-related farm compost and decaying plants, while the YG DOM originated from human activities around the lake. The source characteristics of the YG DOM are obvious, with a high level of biological activity. Five representative areas in the fluorescence regional integral (FRI) were compared. The comparison showed that during the flat water period, the GT water column showed more terrestrial characteristics, even though the humus-like fractions in the DOM of both lakes were derived from microbial decomposition. Principal component analysis (PCA) showed that the agricultural lake water DOM (GT) was dominated by humus components, while the urban lake water DOM (YG) was dominated by authigenic sources.

[Spectral Characteristics Change in Dissolved Organic Matter in Urban River Under the Influences of Different Intensities of Non-point Source Pollution].

With the method of ultraviolet-visible absorption spectroscopy (UV-vis) and excitation-emission matrix spectroscopy combined with parallel factor analysis (EEMs-PARAFAC), this study analyzed the change in dissolved organic matter (DOM) content and composition in spring and summer of two non-point source urban rivers which had different input intensities. The results indicated that the level of humification and molecular weight of DOM in summer was significantly higher than that in spring in these two rivers (P<0.01). The PARAFAC model was used to analyze four chemical compositions, including C1 (UVC fulvic-like), C2 (tryptophan-like), C3 (humic-like), and C4 (UVA fulvic-like); furthermore, C1[(31±6)%] and C2[(31±4)%] were the main fluorescent contents of the water. The high non-point source input river had a higher fluorescence intensity of all four PARAFAC components in spring than in summer, contrary to the low non-point source input river. The random forest regression model showed that C3% had the highest sensitivity to the changes in water parameters (R2=0.75, P<0.001) and could be an effective indicator. Additionally, the coverage level of the water surface (Cover) had an essential effect on the prediction of C4% (P<0.001), and C4% was susceptible to photochemical oxidation. According to the principal component analysis (PCA) and Adonis test, nitrogen and phosphorus were the essential impetuses for the biological process of the river; non-point source inputs and seasonal changes had a significant impact on the urban river (R2=0.775, P<0.001). The contents and compositions of urban river DOM were affected by many essential factors. Non-point source inputs improved the input level of terrestrial humus in the water and promoted the biological process at the same time, dynamically contributing to the changes in the DOM of the water body.

Distribution, sources, and ecological risk assessment of HCHs and DDTs in water from a typical coal mining subsidence area in Huainan, China.

Coal mining subsidence areas are a special and widespread ecosystem in China and many developing countries in the world. However, limited research has focused on HCHs and DDTs in coal mining subsidence areas. Investigating the concentration, distribution, and sources of HCHs and DDTs at the Yangzhuang coal mining subsidence area in Huainan, China, is the object of this study. Water samples from different depths were collected from this region to detect and analyze HCHs and DDTs using gas chromatography-mass spectrometry. The result showed that the concentrations of HCHs and DDTs increased with increasing water depth, and the average concentrations of HCHs and DDTs in the top (T-layer), middle (M-layer), and bottom (B-layer) layers were 152, 169, and 182 ng∙L-1, respectively. Spatial distribution of HCH and DDT concentrations in the study area revealed that the concentrations gradually decreased in the direction of water flow, and the highest concentration was observed at the entrance of the Nihe River. The T-layer was easily influenced by environmental and human activities, while the M-layer and B-layer were mainly influenced by sediment. Using principal component analysis and diagnostic ratios, we found that HCHs and DDTs in the study area mainly originated due to natural and human activities (such as pesticide use). Hexachlorocyclohexanes (HCHs) were mainly derived from lindane, and dichlorodiphenyltrichloroethanes (DDTs) mainly originated due to the recent agricultural use of dicofol; both of these are directly related to agricultural activities. Based on a comparison of reported concentrations of HCHs and DDTs in the rivers and lakes throughout China, we found that the overall ecological risk of HCHs and DDTs in the study area was elevated. The results are important for further understanding the transfer characteristics of HCHs and DDTs as well as the ecological health of the water in coal mining subsidence areas.

Cadmium removal by FeOOH nanoparticles accommodated in biochar: Effect of the negatively charged functional groups in host.

Metallic oxide nanoparticles (NPs) anchored in biochar provide a promising measure forward into the scaled-up application of these NPs in water treatment, and reducing the size of the dwelled NPs is expected to boost the adsorption performance of biochar-based composites because of the size and surface effect. Nevertheless, it is still of great challenge to regulate the size of the impregnated NPs due to their intrinsic self-agglomeration caused by high surface energy. In this study, we fabricated the charged biochar (C-BC) bearing high-density negatively charged groups (i.e., carboxyl and hydroxyl groups) via HNO3 oxidization to load the model metal oxide FeOOH NPs. The average sizes of anchored FeOOH NPs were ultrasmall, ranging from 19.9 ± 1.5 to 3.1 ± 0.5 nm, and decreased with the increased amount of carboxyl and hydroxyl groups in C-BC. Whether in batch adsorption or fixed-bed column setting, adsorption of Cd(II) onto the as-made composites was greatly enhanced by carboxyl and hydroxyl groups in carrier. The normalized adsorption capacities of Cd(II) by ferric mass of the loaded FeOOH were 499.9-724.9 mg/g-Fe, approximately 18.6-27.1 and 2.51-3.64 folds over the bulky FeOOH and FeOOH-impregnated biochar. Our study results should provide a significant reference on how to acquire highly efficient biochar-based composites for water decontamination.

Research on heavy metal level and co-occurrence network in typical ecological fragile area.

Due to the special sensitivity of typical ecologically fragile areas, a series of human life, mining, and other activities have a greater impact on the environment. In this study, three coal mines in Ordos City on the Loess Plateau were selected as the study area, and the pollution levels of heavy metals in the area were studied by measuring As, Hg, Cr, Cd, Cu, Ni, and Pb in the soil of 131 sampling points. Combined with the concept of "co-occurrence network" in biology, the level of heavy metals in soil was studied using geostatistics and remote sensing databases. The results showed that the concentrations of Hg, Cr, Ni, Cu, and Pb in more than half of the sampling points were higher than the local environmental background value, but did not exceed the risk control value specified by China, indicating that human factors have a greater influence, while Cd and As elements are mainly affected Soil parent material and human factors influence. Heavy metal elements have nothing to do with clay and silt but have an obvious correlation with gravel. Cd, Pb, As and Ni, Cd, Cr are all positively correlated, and different heavy metals are in space The distribution also reflects the autocorrelation, mainly concentrated in the northeast of the TS mining area and the middle of the PS mining area.

Development of an acidized biochar-supported hydrated Fe(III) oxides for highly efficient cadmium and copper sequestration from water.

Biochar-supported metallic oxides are attractive adsorbents for heavy metal cleanup, but the adsorption performance is still unsatisfactory as a result of the self-aggregation of the incorporated metallic oxides. A new hybrid nano-material was prepared through impregnating hydrated ferric oxide (HFO) nanoparticles within biochar bearing high-density charged oxygen-containing groups (e.g., carboxyl and hydroxyl groups) (ABC) derived from HNO3 treatment. The as-made adsorbent, denoted as HFO-ABC, possesses highly dispersed HFO nanoparticles with typical size lower than 20 nm, and exhibits greater sorption capacity for Cd(II) and Cu(II) than the pristine biochar-supported HFO. It also shows great sorption preference toward Cd(II) and Cu(II) in co-presence of high levels of Ca2+, Mg2+ and humic acid (HA). Such prominent performance is put down to the high-density charged functional groups on the host ABC, which not only promote the dispersion of the immobilized HFO nanoparticles but also generate the potential Donnan membrane effect, i.e., the pre-concentration and permeation of target metals prior to their preferable adsorption by nano-HFO. The predicted effective coefficients of intra-particle diffusion for Cu(II) and Cd(II) are 3.83 × 10-9 and 4.33 × 10-9 cm2/s, respectively. HFO-ABC exhibits excellent performance for fixed-bed column application, and yields 513 and 990 BV effluents for Cd(II) and Cu(II) to achieve their discharge standards, respectively. The spent HFO-ABC could be in situ regenerated using binary HCl-CaCl2 solution with desorption efficiency higher than 95%. All results manifest that increasing charged functional groups via HNO3 treatment is an effective measure for boosting sorption performance of biochar-based nanocomposites.

Enhanced Removal of Heavy Metals from Water by Hydrous Ferric Oxide-Modified Biochar.

Biochar has become an attractive adsorbent for heavy metal removal, but its application potential is very limited because of the relatively low adsorption capacity and poor selectivity. In the present study, we decorated the biochar (BC) by impregnating hydrous ferric oxide (HFO) within the pore of biochar and consequently obtained a new hybrid adsorbent denoted as HFO-BC. The results show HFO-BC exhibited excellent performance to two representative heavy metals, i.e., Cd(II) and Cu(II), with maximal experimental sorption capacities of 29.9 mg/g for Cd(II) and 34.1 mg/g for Cu(II). HFO-BC showed satisfactory anti-interference ability for Cd(II) and Cu(II) removal in the presence of high levels of Ca(II) and Mg(II) owing to the specific inner-sphere complexation between the immobilized HFO and Cd(II) and Cu(II), which was probed by XPS analysis. Cd(II) and Cu(II) removal onto HFO-BC experienced two distinct stages prior to be adsorbed, i.e., migration from solution to the outside surface of adsorbent and pore diffusion and approached equilibrium within 100 min. In the laboratory-scale small column adsorption experiment, HFO-BC can generate ∼129 and 300 BV effluents for Cd(II) and Cu(II), equivalent to 774- and 1854-fold of its own weight, to meet their treatment standards. Moreover, the exhausted HFO-BC can be effectively regenerated using HCl-CaCl2 binary solution with a desorption rate more than 95%. All results validate that impregnating HFO inside the pores of BC is a promising approach to promote the practical applicability of BC for removing heavy metals from the polluted water.

Challenges and Opportunities in China's Health Aid to Africa: Findings from Qualitative Interviews in Tanzania and Malawi.

BACKGROUND: China has played an increasing role in development aid across Africa. Most recently, China has increased its external investments through the Belt and Road Initiative, China's signature infrastructure and trade drive to link China to Asia and Africa. This is likely to result in continuing growth of China's investment in health in sub Saharan Africa. While conflicting opinions have been raised regarding the motivation and value of these investments, few data have been solicited from those directly involved in China-Africa health aid. We conducted a qualitative study to collect information on perceptions and opinions regarding Chinese-supported health related activities in Africa through in-depth interviews among local African and Chinese participants in Malawi and Tanzania. RESULTS: Our findings reveal shared experiences and views related to challenges in communication; cultural perspectives and historical context; divergence between political and business agendas; organization of aid implementation; management and leadership; and sustainability. Participants were broadly supportive and highly valued Chinese health aid. However, they also shared common insights that relate to challenging coordination between China and recipient countries; impediments to communication between health teams; and limited understanding of priorities and expectations. Further, they share perspectives about the need for shaping the assistance based on needs assessments as well as the importance of rigorous reporting, and monitoring and evaluation systems. Our findings suggest that China faces similar challenges to those experienced by other longstanding development aid and global health donors. As it continues to expand cooperation across Africa and other regions, it will be important for China to consider the issues identified through our study to help inform collaborative and effective global health assistance programs. The insights garnered from this research are not only relevant to China's engagement in Africa but for other global health assistance donors as well.

Delayed Treatment for People Living With HIV in China, 2004-2016: An Analysis of An Observational Cohort.

Early universal access to antiretroviral treatment (ART) is critical in the control of the HIV epidemic. However, prompt initiation of ART remains problematic in China. This study analyzed the late testing and lag time between HIV diagnosis and initiation of ART from 2004 to 2016 and identified the risk factors for delayed initiation of ART. Data from 16,957 people living with HIV were abstracted from a hospital electronic health record database and a case report database for AIDS prevention and control in Yunnan province. Reasons for delayed initiation of ART were categorized into late testing, defined as CD4 count of < 350 cells/µL at baseline HIV diagnosis, and delayed access, defined as a lag time of > 1 month between the diagnosis and initiation of ART. Binary logistic regression models were used to identify risk factors for late testing and delayed access. The CD4 counts at diagnosis increased from 201 ± 147 cells/µL (mean ± SD) in 2004 to 324 ± 238 cells/µl in 2016 (p = 0.024). The CD4 count was higher for persons < 45 years, unmarried, and men who have sex with men (MSM) (356, 357, and 409 cells/µL, respectively) compared to their peers in 2016 (p < 0.05). The lag time from diagnosis to initiation of ART was significantly reduced from 59.2 months in 2004 to 0.9 months in 2016 (p < 0.05). The shorter lag time over the years was consistent when analysis was stratified by sex, age, marital status, and transmission routes, even though the lag time for people using drugs was longest in 2016 (> 2 months versus 0.82 and 0.72 month of heterosexuals and MSM, respectively). Compared to their peers, married persons (AOR = 0.63, 95%CI: 0.57, 0.69) were less likely to have delayed access to ART, and drugs-using patients (AOR = 3.58, 95%CI: 2.95,4.33) were more likely to have delayed access to ART. Late testing rather than delayed access to ART after a diagnosis remains problematic in China, although improvements have been seen for both parameters from 2004 to 2016. Our data highlight the importance of continued efforts to promote early diagnosis of HIV to prevent transmission, morbidity, and early mortality in HIV infection.

Correction to: China's health assistance to Africa: opportunism or altruism?

Please note that following publication of the original article [1], one of the authors has flagged that the abbreviations section lists "BRIC" as "Britain, Russia, India and China".

Distribution, sources and influence factors of polycyclic aromatic hydrocarbon at different depths of the soil and sediments of two typical coal mining subsidence areas in Huainan, China.

The coal mining subsidence area in Huainan is a specific but common ecosystem in China. Not a lot of researches focusing on persistent organic pollutants like polycyclic aromatic hydrocarbons (PAHs) in this area have been done. In order to investigate the concentrations, sources, environmental fate of PAHs and its distribution factors, Yangzhuang and Xieqiao coal mining subsidence areas in Huainan, China were determined as the object of the research, where samples from different depths of soil and sediments were collected to detect and analyze PAHs with Gas Chromatography-Mass Spectrometry. The result showed that the 16 PAH compounds were all detected with a detection rate of 100%. The concentrations of PAHs at different depths of the soil and sediments of Yangzhuang were in the range of 42.1-22149.0 and 44.0-7644.2 ng/g, respectively, and in Xieqiao which were in the range of 17.8-1617.7 and 35.7-264.6 ng/g, respectively. Through comparing the results about spatial interpolation analyses of two subsidence areas, we found that PAHs pollution in soil was heavier than that in sediments of the subsidence areas with relatively small man-made interference. Man-made pollution had a great influence on the vertical distribution of PAHs in the subsidence areas. The PAHs with three or four rings dominated in the areas. Using diagnostic ratios, we found PAHs came from mixed pollutions including the combustion of coal and traffic pollution. As for the influence factors, based on regression analysis and Pearson correlation analysis, the increase of organic matters (OM) and total organic carbon (TOC) favored the deposition of PAHs and had a positive impact on the vertical distribution of PAHs.

Nutrient-derived environmental impacts in Chinese agriculture during 1978-2015.

Nitrogen (N) and phosphorus (P) play a critical role in agricultural production and cause many environmental disturbances. By combing life cycle assessment (LCA) method with the mass balance principle of substance flow analysis (SFA), this study establishes a nutrient-derived environmental impact assessment (NEIA) model to analyze the environmental impacts caused by nutrient-containing substances of agricultural production in China during 1978-2015. The agricultural production system is composed of crop farming and livestock breeding, and the environmental impacts include energy consumption, global warming, acidification, and eutrophication. The results show all these environmental impacts had increased to 8.22*109 GJ, 5.01*108 t CO2-eq, 2.41*107 t SO2-eq, and 7.18*107 t PO43--eq, respectively. It is noted the energy consumption and the climate change caused by the crop farming were always higher than those from livestock breeding, which were average 60 and two times, respectively. While the acidification and the eutrophication were opposite after 1995 and 2000, even they were similar. This was mainly due to the high N application including synthetic N fertilizer (from 1.33*109 GJ to 2.08*109 GJ), applied manure (from 4.94*108 GJ to 5.65*108 GJ) and applied crop residue (from 2.94*108 GJ to 5.30*109 GJ), while the synthetic N fertilizer was controlled and the livestock expanded rapidly after 1995. Among the sub-categories, the three staple crops (rice, wheat, and maize) contributed greater environmental impacts, which were about two to 10 times as other crops and livestock, due to their high fertilizer uses, sown areas and harvests. While the oil crops and fruit consumed the least energies because of their much lower fertilizer-use intensities. Pig and poultry especially pig also caused obvious effects on environment (even 20 times as other livestock) because of their large quantities and excretions, which emitted much higher N2O and P loss resulting in much higher climate change, acidification and eutrophication than other livestock. Then the study proposes the nutrient management in agricultural production by considering crop production, livestock breeding and dietary adjustment, so that some valuable experiences can be shared by the stakeholders in other Chinese regions.

Heavy metals in the soils and plants from a typical restored coal-mining area of Huainan coalfield, China.

This study was conducted to pursue the heavy metals in the soil and plants of a typical restored coal-mining area, China. The average concentrations of Cu, Zn, Cr, Ni, and Pb in soil were 26.4, 76.1, 188.6, 34.3, and 50.2 mg kg-1, respectively, implying a significant accumulation of Cr, Ni, and Pb compared with the background values. Contamination factor indicates that the soil underwent none to medium pollution by Cu and Zn, medium to strong by Cr, none to strong by Pb, and medium pollution by Ni while the pollution load index means that the soil was subjected to intermediate contamination. Based on the critical threshold values to protect the plants, the investigated metals were unable to affect the plants. One-way ANOVA analysis shows that Cu, Zn, and Pb in plants varied with plant tissues. Cu-Cr, Cu-Ni, Zn-Ni, Zn-Pb, Cr-Ni, and Ni-Pb pairs had significant positive correlation both in soil and in plants due to the similar soil characteristics and plant physiologies. Correspondence analysis indicates that Pb was more likely to be accumulative in stems and leaves. In addition, the levels of Cu and Cr in plant followed an order of roots > stems > leaves; Zn and Ni leaves ≥ stems > roots; and Pb followed stems ≥ leaves > roots. Generally, this study suggests that the plants like Ligustrum lucidum Aiton and Weigela hortensis, which are capable of accumulating Cr, Ni, and Pb, should be the predominant species in the studied area.