对“限期治理”的法律探讨

论证限期治理是可诉的具体行政行为，探讨限期治理及其行政处罚的主体适格问题，通过对相关法律规范的剖析和质疑，澄清多种模糊认识，并提出一些建设性意见。     

江河流域综合开发刍议

江河流域综合开发应以土地资源，水资源的利用保护为基础，与其他资源的开发相结合，从深度和广度两方面进行，而且必须与环境保护相协调。     

A review of the technology and applications of methods for evaluating the transport of air pollutants

A variety of methods based on air quality models, including tracer methods, the brute-force method (BFM), decoupled direct method (DDM), high-order decoupled direct method (HDDM), response surface models (RSMs) and so on forth, have been widely used to study the transport of air pollutants. These methods have good applicability for the transport of air pollutants with simple formation mechanisms. However, differences in research conclusions on secondary pollutants with obvious nonlinear characteristics have been reported. For example, the tracer method is suitable for the study of simplified scenarios, while HDDM and RSMs are more suitable for the study for nonlinear pollutants. Multiple observation techniques, including conventional air pollutant observation, lidar observation, air sounding balloons, vehicle-mounted and ship-borne technology, aerial surveys, and remote sensing observations, have been utilized to investigate air pollutant transport characteristics with time resolution as high as 1 sec. In addition, based on a multi-regional input-output model combined with emission inventories, the transfer of air pollutant emissions can be evaluated and applied to study the air pollutant transport characteristics. Observational technologies have advantages in temporal resolution and accuracy, while modeling technologies are more flexible in spatial resolution and research plan setting. In order to accurately quantify the transport characteristics of pollutants, it is necessary to develop a research method for interactive verification of observation and simulation. Quantitative evaluation of the transport of air pollutants from different angles can provide a scientific basis for regional joint prevention and control.     

放射性核素钍污染土壤有机酸化学淋洗工艺

选用草酸、柠檬酸和酒石酸对不同粒径典型放射性钍污染土壤进行淋洗试验,考察淋洗后淋洗液各指标参数变化,以土壤可提取形态分析淋洗后流动性和稳定性的变化,结合淋洗动力学和XRD手段来表征土壤修复机理及土壤晶相破坏程度.结果表明：草酸、柠檬酸和酒石酸振荡淋洗最优参数为0.5mol/L条件下振荡8h,淋洗效果依次为：草酸>柠檬酸>酒石酸>苹果酸>乙酸.达到修复目的前提下,淋洗后土壤整体晶相破坏程度较小,二氧化硅衍射峰明显增强,各土样中残渣态的占比提高19.39%~27.20%、0.63%~8.45%,流动性降低6.81%~11.33%,稳定性得到增强,为放射性污染土壤化学淋洗修复提供参考.     

Fine particulate matter (PM2.5/PM1.0) in Beijing, China: Variations and chemical compositions as well as sources

Particulate matter (i.e., PM_1.0 and PM_2.5), considered as the key atmospheric pollutants, exerts negative effects on visibility, global climate, and human health by associated chemical compositions. However, our understanding of PM and its chemical compositions in Beijing under the current atmospheric environment is still not complete after witnessing marked alleviation during 2013–2017. Continuous measurements can be crucial for further air quality improvement by better characterizing PM pollution and chemical compositions in Beijing. Here, we conducted simultaneous measurements on PM in Beijing during 2018–2019. Results indicate that annual mean PM_1.0 and PM_2.5 concentrations were 35.49 ± 18.61 µg/m³ and 66.58 ± 60.17 µg/m³, showing a positive response to emission controls. The contribution of sulfate, nitrate, and ammonium (SNA) played an enhanced role with elevated PM loading and acted as the main contributors to pollution episodes. Discrepancies observed among chemical species between PM_1.0 and PM_2.5 in spring suggest that sand particles trend to accumulate in the range of 1–2.5 µm. Pollution episodes occurred accompanied with southerly clusters and high formation of SNA by heterogeneous reactions in summer and winter, respectively. Results from positive matrix factorization (PMF) combined with potential source contribution function (PSCF) models showed that potential areas were seasonal dependent, secondary and vehicular sources became much more important compared with previous studies in Beijing. Our study presented a continuous investigation on PM and sources origins in Beijing, which provides a better understanding for further emission control as well as a reference for other cities in developing countries.     

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in a sediment core from Lake Dagze Co, Tibetan Plateau, China: Comparison of three receptor models

Receptor models are a useful tool for identifying sources of polycyclic aromatic hydrocarbons (PAHs) in multiple environmental media. In this study, three different receptor models (including the principal component analysis-multiple linear regression (PCA-MLR), positive matrix factorization (PMF), and Unmix models) were used to apportion the sources of 16 priority PAHs in a sediment core of Lake Dagze Co. The ∑PAHs (sum of all 16 measured PAHs) concentrations ranged from 51.89 to 132.82 ng/g with an average of 80.39 ng/g. The ∑PAHs were dominated by 2-3 ring PAHs, accounting for 80.12% on average, thereby indicating that they mainly originated from biomass and coal combustion and/or from long-range atmospheric transportation. The three models produced consistent source apportionment results. The greatest contributor to ∑PAHs was biomass combustion, followed by coal combustion, vehicle emissions, and petrogenic sources. Moreover, the temporal variation of the common sources was well-correlated among models. The multi-method comparison and evaluation results showed that all three models were useful tools for source apportionment of PAHs, with the PMF model providing better results than the PCA-MLR and Unmix models. The temporal trends of factor contributions were verified by PAHs with different ring numbers. Significant correlations were found between the simulated concentrations of each source factor and the PAHs with different ring numbers (P<0.01), except for the petrogenic source identified by the Unmix model (P>0.05). This study can provide useful information for further investigation of source apportionment of PAHs in the sediment cores.     

Effects of multi-phase inoculation on the fungal community related with the improvement of medicinal herbal residues composting

Environmental Science and Pollution Research - Composting has become the most important way to recycle medicinal herbal residues (MHRs). The traditional composting method, adding a microbial agent...     

Transmission of SARS-CoV-2 virus and ambient temperature: a critical review

Environmental Science and Pollution Research - The coronavirus disease 2019 (COVID-19) pandemic has brought unprecedented public health, and social and economic challenges. It remains unclear...     

Occurrence,spatial distribution,sources, and risks of polychlorinated biphenyls and heavy metals in surface sediments from a large eutrophic Chinese lake (Lake Chaohu)

Surface sediment from large and eutrophic Lake Chaohu was investigated to determine the occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls (PCBs) and heavy metals in one of the five biggest freshwater lakes in China. Total concentration of PCBs (Σ₃₄PCBs) in Lake Chaohu was 672 pg g^?1 dry weight (dw), with a range of 7 to 3999 pg g^?1 dw, which was lower than other water bodies worldwide. The majority of heavy metals were detected at all sampling locations, except for Sr, B, and In. Concentrations of Al, Fe, Ca, Mn, Sr, Co, Zn, Cd, Pb, and Hg were similar to that reported for other lakes globally. Concentrations of K, Mg, Na, Li, Ga, and Ag were greater than the average, whereas those of Cr, Ni, and Cu were lower. Cluster analysis (CA) and positive matrix factorization (PMF) yielded accordant results for the source apportionment of PCBs. The technical PCBs and microbial degradation accounted for 34.2 % and 65.8 % of total PCBs using PMF, and PMF revealed that natural and anthropogenic sources of heavy metals accounted for 38.1 % and 61.8 %, respectively. CA indicated that some toxic heavy metals (e.g., Cd, In, Tl, and Hg) were associated with Ca–Na–Mg minerals rather than Fe–Mn minerals. The uncorrelated results between organic matter revealed by pyrolysis technology and heavy metals might be caused by the existence of competitive adsorption between organic matter and minerals. PCBs and heavy metals were coupling discharge without organochlorine pesticides (OCPs), but with polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). No sediment sample exceeded the toxic threshold for dioxin-like PCBs (dl-PCBs) set at 20 pg toxicity equivalency quantity (TEQ)?g^?1, (max dl-PCBs, 10.9 pg TEQ g^?1). However, concentrations of Ag, Cd, and Hg were at levels of environmental concern. The sediment in the drinking water source area (DWSA) was threatened by heavy metals from other areas, and some fundamental solutions were proposed to protect the DWSA.