重庆市住宅楼环境电磁辐射的初步测量与分析

初步探测重庆市住宅楼环境电磁辐射的现状及其影响因素,为建立人居环境电磁场特征数据库提供依据。按照国家标准的要求和方法,在重庆市选择4个典型居住小区,分别测量各小区住宅楼不同楼层电梯门口或楼梯间以及各住宅楼楼顶的电磁辐射水平,结果表明,本次横断面调查中,在1MHz～40GHz频段,各栋楼的综合场强为17.13～17.18V/m,已接近GB 8702-88《电磁辐射防护规定》的公众照射导出限值,各楼层间差异无统计学意义(P>0.05)。在5～1000Hz频段,各栋楼楼内综合场强分布差异无统计学意义(P>0.05),而临近高压线的住宅楼楼顶综合场强明显高于其他小区楼顶以及同一栋楼其他楼层的综合场强(P<0.05),并且该楼各楼层的磁场强度明显高于其他住宅楼(P<0.05)。所测住宅楼的环境电磁辐射水平未超出国家相应标准限制,不同楼层电磁辐射水平与极低频辐射源的分布有关。     

220 kV高压输电线电磁辐射水平及防护距离预测

依据<500 kV超高压送变电工程电磁辐射环境影响评价技术规范>(HJ/T 24-1998)中的预测模式对监测点周围地面1.5 m处工频电场进行了验证性监测,表明实际测定结果与理论计算结果基本吻合.通过对220 kV双回同相、双回逆相和单回线路下地面1.5 m、4.5 m、和7.5 m处工频电场变化趋势分析,预测了220 kV高压输电线产生的电磁辐射水平,以及不同房屋结构的防护距离.提出了220 kV高压输电线电磁辐射的防护措施.     

The measurement procedure in the SEMONT monitoring system

The measurement procedure of the open area in situ electric field strength is presented, acquiring the real field data for testing of the Serbian electromagnetic field monitoring network (SEMONT) and its Internet portal. The SEMONT monitoring system introduces an advanced approach of wireless sensor network utilization for the continuous supervision of overall and cumulative level of electromagnetic field over the observed area. The aim of the SEMONT system is to become a useful tool for the national and municipal agencies for the environmental protection, regarding the electromagnetic pollution monitoring and the exposure assessment of the general population. Considering the public concern on the potentially harmful effects of the long-term exposure to electromagnetic radiation, as well as the public transparency principle that is incorporated into the Serbian law on non-ionizing radiation protection, the SEMONT monitoring system is designed for the long-term continuous monitoring, presenting real-time measurement results, and corresponding exposure assessment over the public Internet network.     

北京市某高层建筑高空电磁辐射环境影响分析

选取北京市某代表性高层居民楼顶平台作为高空电磁辐射环境水平监测点进行综合场强和选频监测,评价总体电磁辐射环境水平,并分析监测区域电磁辐射能量的来源。结果表明：该高空监测区域的电磁辐射环境总体水平低于国家规定的公众照射导出限值,但高于地面水平。监测区域主要受30 km 外的中波台影响,其次是9 km 外的中央电视塔。影响最大的是639 kHz频率的中波信号,占100 kHz～300 MHz总场强的95％以上,其次是1．28 MHz频率的中波信号。提出,开展敏感建筑物规划建设时,应考虑中波的传播特性和对环境的影响。     

中波台电磁辐射叠加影响估算及与实测对比分析

以某中波电台为例,对多个不同频率的中波发射台同时运行时复合场强进行理论估算,对电磁辐射叠加影响进行分析,并将理论估算值与该台电磁辐射环境现状监测数据进行比对,得出距离发射塔近,复合场强理论估算值高于实测值,距离较远理论估算值与实测值较接近等结论。     

The spatial statistics formalism applied to mapping electromagnetic radiation in urban areas

Determining the electromagnetic radiation levels in urban areas is a complicated task. Various approaches have been taken, including numerical simulations using different models of propagation, sampling campaigns to measure field values with which to validate theoretical models, and the formalism of spatial statistics. In the work, we present here that this latter technique was used to construct maps of electric field and its associated uncertainty from experimental data. For this purpose, a field meter and a broadband probe sensitive in the 100-kHz–3-GHz frequency range were used to take 1,020 measurements around buildings and along the perimeter of the area. The distance between sampling points was 5 m. The results were stored in a geographic information system to facilitate data handling and analysis, in particular, the application of the formalism of spatial statistical to the analysis of the distribution of the field levels over the study area. The spatial structure was analyzed using the variographic technique, with the field levels at non-sampled points being interpolated by kriging. The results indicated that, in the urban area analyzed in the present work, the linear density of sampling points could be reduced to a distance which coincides with the length of the blocks of buildings without the statistical parameters varying significantly and with the field level maps being reproduced qualitatively and quantitatively.     

变电站电磁环境监测布点建模仿真研究

针对变电站电磁环境自动监测站布点方案普遍存在的效率不高、科学性不足等问题,以某500 kV变电站电磁环境自动监测站选址为例,通过建模仿真得到该变电站工频电场和工频磁场的空间分布,并实测验证了仿真结果的准确性。通过统计该变电站工频电场和工频磁场的空间分布特征,提出了基于变电站空间场强分布特征的自动监测站布点方案,建议优先在场强中位数分界线附近区域布点,以更好地反映变电站电磁环境。研究结果可指导变电站电磁环境自动监测站选址,提高变电站电磁环境监测布点的科学性,提升监测效率。     

GSM移动通信基站电磁辐射污染状况研究

介绍了GSM移动通信基站系统,指出,在进行GSM移动通信基站环境影响分析时,要注意采样点位的设置和测量要求.现场监测结果表明,GSM移动通信基站对环境电磁辐射水平有一定的影响,特别是对50 m内建筑物影响显著,但绝大多数基站基本符合国家有关电磁辐射环境影响标准的要求,在设备正常运行情况下,不会对周围环境造成电磁辐射污染.     

不同布置方式220 kV变电所对周围环境的电磁辐射分布

通过对不同布置方式220 kV电压等级变电所在运行中对周围环境产生的工频电场、磁感应强度和无线电干扰的监测分析,了解了不同布置方式220 kV电压等级变电所对周围环境电磁辐射的分布规律.指出在建设220 kV电压等级变电所的同时,只要做好建筑屏蔽和电缆入地等工作,就可以降低对周围环境的电磁辐射影响.     

Patchy Distribution Fields: Sampling Distance Unit of an Interleaved Survey and Reconstruction Adequacy

A mathematical model was used to examine the effects of choosing various units of sampling distance of an interleaved (two-pass) acoustic survey on the adequacy of reconstructing patchy distribution fields. The model simulates fish or plankton patches (or gaps) of different shapes and spatial orientations, and an interleaved survey by parallel or zigzag transects, along which a unit of sampling distance is set. The efficiency of a survey is determined by the adequacy of a reconstructed field to that originally generated, which is evaluated by calculating their correlations (r). Regarding immovable fields, the experiments conducted indicate that a patchy field can be reconstructed properly (r ² > 0.70) if the distance between transects D < (1.5–2.0)R and the unit of sampling distance d < (1.5– 2.0)R _p. As, for regular surveys d < (1.0–1.5)R _p, it may be concluded that interleaved surveys are more efficient than regular ones because of the factor studied. In regard to movable fields, a comparison of the results of interleaved surveys with those of regular surveys directly indicates that the former may ensure a more adequate field reconstruction than the latter do. This fact confirms the previous conclusion that an interleaved survey is expedient in cases where there is no preference regarding the position of a vessel for further work.     

环境电磁辐射测量比对

为考核辐射环境监测质量,浙江省辐射环境监测站组织了2010年全省辐射环境监测网络环境电磁辐射测量比对。采用稳健Z比分数法评价测量数据的一致性。结果表明,射频综合场强测量比对中,9台仪器测量结果满意,1台仪器测量结果离群。工频电磁场测量比对中,有9台仪器测量结果满意,2台仪器测量结果离群。88%的测量值为满意结果,12%为离群结果,测量比对有效地发现了测量仪器存在的问题,保证监测工作结果的准确性。     

Spatial Relationships Between Water Quality and Pesticide Application Rates in Agricultural Watersheds

Pesticide applications to agricultural lands in California, USA, are reported to a central data base, while data on water and sediment quality are collected by a number of monitoring programs. Data from both sources are geo-referenced, allowing spatial analysis of relationships between pesticide application rates and the chemical and biological condition of water bodies. This study collected data from 12 watersheds, selected to represent a range of pesticide usage. Water quality parameters were measured during six surveys of stream sites receiving runoff from the selected watershed areas. This study had three objectives: to evaluate the usefulness of pesticide application data in selecting regional monitoring sites, to provide information for generating and testing hypotheses about pesticide fate and effects, and to determine whether in-stream nitrate concentration was a useful surrogate indicator for regional monitoring of toxic substances. Significant correlations were observed between pesticide application rates and in-stream pesticide concentrations (p < 0.05) and toxicity (p < 0.10). In-stream nitrate concentrations were not significantly correlated with either the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.30). Neither total watershed area nor the area in which pesticide usage was reported correlated significantly with the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.14). In-stream pesticide concentrations and effects were more closely related to the intensity of pesticide use than to the area under cultivation.     

南通市移动通信基站电磁辐射时空分布特征

为了解南通市移动通信基站电磁辐射时空分布特征,随机实测504座典型基站,着重从水平和垂直方向50 m范围内开展监测,并选取典型基站开展24 h连续监测。结果表明,南通市移动通信基站电磁辐射水平满足《电磁环境控制限值》(GB 8702—2014)中公众曝露控制限值要求;基站电磁辐射水平分布随距离增大呈现先增加后逐渐减小的趋势,地面最大投射点的距离基本为20~30 m;垂直方向最大监测值出现在与天线高度相近的楼层;24 h基站电场强度随时间呈明显变化,与话务量和数据流量分别进行相关性分析,相关系数为0.968 3和0.709 8,说明目前话务量仍是电磁辐射强度的重要影响因素。     

Bioavailability of copper,cadmium, zinc,and lead in tropical savanna soils assessed by diffusive gradient in thin films (DGT) and ion exchange resin membranes

The technique of diffusion gradient in thin films (DGT) for assessing bioavailable metals has not been tested under field conditions. We assessed the relationships of DGT- and cation exchange resin-membrane-measured concentrations of Cd, Cu, Pb, and Zn with plant uptake of the metals under greenhouse and field conditions. In the greenhouse, the effective concentrations of Cu, Pb, and Zn by DGT correlated significantly with uptake by sorghum (Sorghum bicolor), but cation exchange resin-membrane-measured concentrations of Cd, Pb, and Zn did not correlate with sorghum uptake. In the field, the DGT-measured concentrations of Cd, Pb, and Zn were not linearly related to uptake Cd, Pb, and Zn by lettuce (Lactuca sativa) except for Cu uptake (r = 0.87, p < 0.05). Similarly, it was only the resin-membrane-extractable Pb that correlated with Pb uptake by lettuce (r = 0.77; p < 0.05). However, fitting non-linear regression models improved the plant metal uptake predictions by DGT-measured bioavailable Cd, Cu, Pb, and Zn under field conditions. In conclusion, the DGT technique was fairly predictive of bioavailability in the greenhouse, but not in the field.     

北京城区道路电磁环境监测及与人口热力关联分析

用电设备和无线通信服务的增长导致城市电磁环境水平逐渐升高,对人体健康和电子系统正常工作构成潜在威胁。于2021年对北京城区约407 km道路上的28 578个采样点进行电磁环境监测,89%的采样点电磁环境水平在3 V/m以内,但存在少量电磁环境水平高于12 V/m的采样点。结合进一步频谱分析发现,地理坐标为116.48°E、39.91°N附近路段电磁环境水平超出了《电磁环境控制限值》(GB 8702—2014)要求。此外,利用关联分析经典算法Apriori对电磁环境和人口热力的关联规则进行提取,结果表明,电磁环境水平较高的区域往往具有极高等级的人口热力,从而为电磁环境风险的快速判别提供参考。建议重点加强对人口热力极高区域的电磁环境监测,同时持续关注城市电磁环境变化趋势,以实现对电磁环境风险的及早预警和处理。     

Assessment of the exposure of two fish species to metals pollution in the Ogun river catchments, Ketu, Lagos, Nigeria

The concentrations of metals (Ca, Cd, Fe, Mn, Pb and Zn) were determined by flame atomic absorption spectrophotometry in water, sediments and fish samples in the Ogun river catchments, Ketu, Lagos, which is an important bird nesting, fishing and drinking water source. The results show that the southern tip bothering the Lagos lagoon is where the highest metal concentrations are found in the fish species (Tilapia sp. and Chrysichthys sp.), whereas the Agboyi creek segment near the lagoon with higher surrounding human population density recorded higher levels of metals in sediments and water samples. The two fish species accumulated different amounts of metals. However, the differences were not statistically different at p < 0.05. There is a significant correlation (p < 0.05) for Cd concentration in water. The concentrations of Pb in sampling points 3 and 4 as well as Cd, Mn and Fe in all six sampling points exceeds the World Health Organization (WHO) limits for drinking water. Levels of metals obtained for sediments are within the range reported for Nigeria’s river sediments. Based on this study, the human risks for heavy metals in the harvested fish species from the Ogun river catchments, Ketu, are low for now as the concentrations were below the recommended Food and Agriculture Organization (FAO) maximum limits for Pb (0.5 mg/Kg), Cd (0.5 mg/Kg), and Zn (30 mg/Kg) in fish.     

Rangeland and pasture monitoring: an approach to interpretation of high-resolution imagery focused on observer calibration for repeatability

Collection of standardized assessment and monitoring data is critically important for supporting policy and management at local to continental scales. Remote sensing techniques, including image interpretation, have shown promise for collecting plant community composition and ground cover data efficiently. More work needs to be done, however, evaluating whether these techniques are sufficiently feasible, cost-effective, and repeatable to be applied in large programs. The goal of this study was to design and test an image-interpretation approach for collecting plant community composition and ground cover data appropriate for local and continental-scale assessment and monitoring of grassland, shrubland, savanna, and pasture ecosystems. We developed a geographic information system image-interpretation tool that uses points classified by experts to calibrate observers, including point-by-point training and quantitative quality control limits. To test this approach, field data and high-resolution imagery (∼3 cm ground sampling distance) were collected concurrently at 54 plots located around the USA. Seven observers with little prior experience used the system to classify 300 points in each plot into ten cover types (grass, shrub, soil, etc.). Good agreement among observers was achieved, with little detectable bias and low variability among observers (coefficient of variation in most plots <0.5). There was a predictable relationship between field and image-interpreter data (R ² > 0.9), suggesting regression-based adjustments can be used to relate image and field data. This approach could extend the utility of expensive-to-collect field data by allowing it to serve as a validation data source for data collected via image interpretation.     

广州市GSM移动电话基站发射电磁波对环境污染影响分析

依据国标《环境电磁波卫生标准》(GB91 75 -88) ,从理论上讨论了 GSM移动通信基站电磁辐射对环境的影响 ;并利用若干基站的实际测试数据 ,说明在一般情况下 ,对于基站周围的民居或其它楼宇里居住或工作的人群 ,移动通信基站的电磁辐射强度远低于国家标准 ,也远低于美国的标准     

城市移动通信基站电磁辐射环境调查与评价——以连云港为例

对连云港移动通信基站电磁辐射环境进行现状调查与评价,将3个时段内移动基站电磁辐射监测数据进行统计分析和分区评价。结果表明,监测数据均能符合相应的环境标准,县域电磁环境辐射水平整体略低于城市区域,基站周边整体受电磁辐射影响程度随高度上升呈增加趋势,10 m～15 m高度处的综合场强平均峰值最高。     

Organophosphate pesticide environmental exposure: analysis of salivary cholinesterase and carboxilesterase activities in preschool children and their mothers

A pilot study was conducted to evaluate the usefulness of salivary cholinesterase and carboxylesterase as biomarkers of exposure to environmental organophosphate pesticides. Ninety samples were obtained from women and 62 samples from their preschool-aged children who live near an agricultural area of the Upper Valley of the Negro River (Patagonia, Argentina) where pesticides are applied 6 months a year. Each participant donated two samples under similar conditions: one in the pre-exposure period and another during the pulverization period. Demographic information, potential confounders, and risk behaviors were registered. Active or passive smoking had no effect on these enzyme activities in either group. During the pulverization period, cholinesterase activity was not detectable in 76% of the children's samples and 23% of the mothers' samples. Comparing samples collected during the pulverization period with respect to the pre-pulverization period, the average mother and child cholinesterase activity decreased by 65.7% (p < 0.001) and 85.8% (p < 0.001), respectively. Also, mother and child carboxylesterase activity decreased by 27.5% (p < 0.001) and 41.9% (p < 0.01), respectively. Child carboxylesterase activity in the pulverization period was associated to the habit of eating dust outdoors (p < 0.01). The most frequent inhibition levels observed for cholinesterase and carboxylesterase activity were between 70–100% and 0–29%, respectively, in both groups studied. This shows that at the same level of exposure, cholinesterase was more sensitive to inhibition than carboxylesterase. Therefore, carboxylesterase might more properly reflect the degree of environmental organophosphate exposure and may have potential as a novel tool for biomonitoring.