环境监测优化布点的综合因子得分法

在主成分分析的基础上提出了一种新的环境优化布点的方法——综合因子得分法。该方法先将多维环境指标矩阵投影到其主成分空间,然后将其与对应的方差贡献率进行加权求得综合因子得分,综合因子得分值越大表示该监测点综合环境质量越差,根据综合因子得分值的大小就可对监测点样本集进行合理分类。应用实例表明,该方法用于环境监测优化布点,具有计算简便、快速,计算结果稳健,分析合理,易于推广等优点。     

南宁市土壤中正构烷烃的污染特征及来源解析

为研究南宁市土壤中正构烷烃的赋存情况以及来源,于2021年6月在南宁市内采集了48个土壤样品,采用气相色谱质谱法(GC-MS)对表层土壤中正构烷烃的质量分数进行了测定。结果表明,正构烷烃碳链长度范围为C12—C35,∑24正构烷烃的质量分数为3.93~131.02μg/g,其中C31质量分数最高,C22以上的高碳正构烷烃具有明显的奇偶优势,体现了典型的高等植物来源的特点。碳优势指数等参数分析结果表明,土壤中的正构烷烃主要来自陆地高等植物且总体上木本植物>草本植物,少部分可能存在石油污染。主成分分析(PCA)结果表明,C29—C35具有同源性,主要受植物叶蜡影响(41.36%),C24和C25主要来自水生植物(27.88%),C16和C18可能是细菌和石油化合物排放共同影响的结果(21.49%)。根据主成分分析中样品的贡献权重得出,可能存在石油化合物输入的土壤63.6%来自耕地,27.3%来自林地,9.1%来自园地,研究区土壤中正构烷烃的主要人为排放源可能受到农业机械排放以及靠近道路周边受交通排放的影响。     

The Seasonal Variation of the Concentrations of Ozone, Sulfur Dioxide, and Nitrogen Oxides in Two Nigerian Cities

A combination of multivariate statistical methods including factor analysis, principal component analysis, principal component regression, and multiple linear regression (MLR) were employed to evaluate the influence of seasons on the concentrations of ozone, sulfur (IV) oxide, and oxides of nitrogen in ambient air of Nigerian cities of Lagos and Ilorin. The former city is located in the coastal area, and it is highly congested with a high intensity of marine, vehicular, and industrial activities, and the latter city is a medium size town, located in the central guinea savannah zone of Nigeria. Samples were collected using a high-volume sampler from near the ground at various sites of diverse human and industrial activities, during wet and dry seasons from 2003 to 2006. The PCA reveals three distinct groupings during the day for all data, which is a reflection of different factors contributing to the atmospheric chemistry of these cities. The predicted ozone concentration values by MLR agree fairly well with the measured data. The dependence of ozone on meteorological parameters including relative humidity, air temperature, and sun exposure and the precursor pollutants depends on weather and the anthropogenic activities. The results for the two cities indicate that reduction in the level of NO₂ is accompanied by an increase in the level of ozone, suggesting the interconversion between the two via photochemical activity.     

A critical appraisal of PAH indices as indicators of PAH source and composition in Elelenwo Creek,southern Nigeria

The survey of polycyclic aromatic hydrocarbons (PAHs) and their relation to potential pollution sources were investigated in suspended particulate matter (SPM), surface waters, and sediments from Elelenwo Creek, southern Nigeria. Total PAH concentrations varied from 2,021.35 to 3,926.84 μg/kg dry weights in SPM and from 4,238.00 to 5,490.84 μg/kg dry weights in sediments. Furthermore, concentration levels of PAHs varied from 720.46 to 857.65 μg/l in the surface waters, which indicates that the aquatic ecosystem is polluted by PAHs. The 2, 3-ring PAHs were not dominant in SPM (34.73%), surface water (40.09%), and sediments (22.43%). While anthracene was more abundant, of the 2, 3-ring PAHs in SPM, the most abundant in the surface waters and sediments were fluorene and acenaphthylene. Four origin indices or concentration ratios of PAH isomer pairs were used to evaluate the suitability of these compounds as tracers to distinguish between the contamination arising from different sources. A critical appraisal of the PAH indices, therefore, suggested that biomass combustion is the major PAH source in the environmental matrices. Relative PAH patterns in the environmental matrices were also evaluated using principal component analysis, and were found to correlate with the PAH patterns of the different potential contamination sources.     

A field survey—Staroe lake suffering from atmospheric deposition in the region north of the Arctic Circle

Background, aim, and scope  The Arctic holds large stores of minerals, and extracted materials are provided to the world’s economy; in this sense, the Arctic issue associated with mining is not local but global. In a part of the Arctic region (the Kola Peninsula, 66–70° N and 28–41° E), metal levels are generally elevated in the lake sediment. There is a question as to what results in elevated metal levels—a natural process (naturally abundant minerals) or an anthropogenic process (mining and metallurgy). In terms of solving this question, Staroe lake located on the Kola Peninsula was researched as a case study. Materials and methods  The following parameters were determined in relation with Staroe lake: (1) the current quality of the lake’s water—each 1,000-ml sample was collected at a surface point and a deep point (near the bottom layer), and the collected samples were directly analyzed after filtration; (2) atmospheric bulk deposition—bulk deposition was collected using a set of three rainwater samplers near the lake. In addition, bulk deposition was collected in a background site (250 km to the southwest of the smelter complex) as a reference; and (3) sediment profile (plus principal component analysis)—lake-bottom sediment was collected by an open-gravimetric column sampler equipped with an automatic diaphragm. After collection, the sample columns were cut at a 1-cm interval for analysis. Eigenvalues and variances by factor were calculated from the correlation coefficients. Results  The obtained data show that (1) naturally poor elements (Cu, Ni, Si, and SO₄ ²⁻) dominantly influence the lake’s water quality; (2) they are transported from the anthropogenic sources to the study lake through the atmospheric pathway; (3) mainly the contents of Cu, Ni, Sr, and Ca have influenced the sediment quality since the 1950s, corresponding to the industrial movement; and (4) Cu, Ni, and Sr originate from an anthropogenic source (smelter), and Ca originates from both natural and anthropogenic sources. Discussion  As compared with the Russian standard (San Pin 2.1.980–00), the contents of NO₃ ⁻ (50.3 ± 0.1 mg l⁻¹) and particulates (2.3 ± 0.2 mg l⁻¹) exceeded the standard levels (0.7 mg l⁻¹ NO₃ ⁻ and 45 mg l⁻¹ particulates); Staroe lake may be slightly contaminated. However, the contamination factor (comparison with the background data) implies that Staroe lake is considerably contaminated. There is a strong possibility that fine overburden detritus (<0.1 mm diameter) may be transported from an open pit to the study lake by natural forces such as wind. Although it is difficult to suppose that one factor dominantly affects the sediment quality, it follows from a factor analysis that factors 1 and 2 account for about 70% of the total variance: Factor 1 is the most dominant, and factor 2 is the second most dominant in the variability of sediment quality. It is considered that Cu, Sr, and Ni in factor 1 originate from anthropogenic sources because they are poor in sediment rocks. Conclusions  The field survey conducted in Staroe lake can give the following answers to the key objectives: (1) The present water quality is affected by Cu, Ni, Si, and SO₄ ²⁻ in light of the contamination factor, and these elements originate from anthropogenic sources (the smelter and the open pit) and are transported to the lake through the atmospheric pathway; (2) the sediment profile and statistic analysis show that the lake quality has been influenced by deposition of metals since the 1950s; and (3) Cu, Ni, Sr, and Ca have influenced the sediment quality in light of the most dominant factor—Cu, Ni, and Sr originate from an anthropogenic source, whereas Ca comes from both natural and anthropogenic sources. Recommendations and perspectives  The presented lake survey shows that the dispersion of human-related pollutants via the atmospheric pathway takes place in the Arctic region. If the current pollution continues without countermeasures, the high-latitude environment may lose its original characteristics; hence, this subject is important when considering how to implement a wide range of environmental protection measures in the Arctic.     

用锥面砧镦粗减小镦偏的分析

由于剪切坯料端面偏斜,拍扁时压成椭圆形,此文称此现象为镦偏。此文分析了用锥形砧镦粗减小镦偏的作用,建立了分步压缩的主应力法计算模型模拟减小镦偏过程,描述了锥砧的斜角、接触面摩擦系数、压下量等参量对减小镦偏的作用,给出了具有参考价值的计算结果。     

Effect of outside air ventilation rate on volatile organic compound concentrations in a call center

A study of the relationship between outside air ventilation rate and concentrations of volatile organic compounds (VOCs) generated indoors was conducted in a call center office building. The building, with two floors and a total floor area of 4600 m², is located in the San Francisco Bay Area, CA. Ventilation rates were manipulated with the building's four air handling units (AHUs). VOC and CO₂ concentrations in the AHU returns were measured on 7 days during a 13-week period. VOC emission factors were determined for individual zones on days when they were operating at near steady-state conditions. The emission factor data were subjected to principal component (PC) analysis to identify groups of co-varying compounds. Potential sources of the PC vectors were ascribed based on information from the literature. The per occupant CO₂ generation rates were 0.0068–0.0092 l s⁻¹. The per occupant isoprene generation rates of 0.2–0.3 mg h⁻¹ were consistent with the value predicted by mass balance from breath concentration and exhalation rate. The relationships between indoor minus outdoor VOC concentrations and ventilation rate were qualitatively examined for eight VOCs. Of these, acetaldehyde and hexanal, which likely were associated with material sources, and decamethylcyclopentasiloxane, associated with personal care products, exhibited general trends of higher concentrations at lower ventilation rates. For other compounds, a clear inverse relationship between VOC concentrations and ventilation was not observed. The net concentration of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate isomers, examples of low-volatility compounds, changed very little with ventilation likely due to sorption and re-emission effects. These results illustrate that the efficacy of ventilation for controlling VOC concentrations can vary considerably depending upon the operation of the building, the pollutant sources and the physical and chemical processes affecting the pollutants. Thus, source control measures, in addition to adequate ventilation, are required to limit concentrations of VOCs in office buildings.     

Heavy metals contamination of soils under oak ecosystems in the Sofia region

We studied the contamination of Cu, Zn, Pb, and Cd in soils under oak ecosystems of urban (U), suburban (SU), and rural (R) regions in Sofia, Bulgaria. The urban sampling sites are located in the large forest parks of Sofia under oak ecosystems, while the others are located between the centre of the town and the surrounding mountains and are also from oak ecosystems. The concentrations of Cu, Zn, Pb, and Cd in soils were measured for identifying the sources and degree of contamination, and calculating the concentration coefficients (Hc) and enrichment factors (EF). The result of applying principal component analysis (PCA), showed that Cd and Pb accounted for the anthropogenic pollution and could be inferred as its tracers, whereas Cu is located mainly in the parent material. The Zn concentration levels were controlled both by its original content in the parent material as well as by anthropogenic pollution. The results obtained for the city forest parks allow for their successful use for recreation purposes.     

环境污染纠纷行政调解中须注意的几个问题

指出了环境污染纠纷的行政调解不同于行政处罚,一般性地阐述了行政调解的原则。     

Dissecting the spatial scales of mercury accumulation in Ontario lake sediment

Total mercury concentration was analyzed in 171 lakes from pre-industrial (>30 cm depth; Hg_{pre-industrial}) and present-day sediments (0.5–1 cm; Hg_present-day). Numerous hot or cold spots of sediment mercury enrichment (Hg EF; Hg_{pre-industrial}/Hg_present-day) were evident as determined by local tests of autocorrelation, although in most cases, the maximum correlation among sites was not the nearest neighbor, indicating a strong influence of watershed characteristics. Hg EF was correlated with the area of open water (ha) (r = 0.91, p = 0.035), mine tailings (r = 0.94, p = 0.019), and organic deposits in surficial geology of the watershed (r = −0.91, p = 0.034). Through use of local rather than global regression coefficients, R² increased from 0.20 (p = 0.005) to 0.60 (p = 0.013). A broad spatial pattern (>500 km) observed only in Hg_{pre-industrial} was best explained by mean annual precipitation (shared variance = 3.5%), while finer spatial patterns only observed in Hg_present-day and Hg EF were best explained by pH (average shared variance = 10.8%).