Distribution of polybrominated diphenyl ethers in breast milk,cord blood and placentas: a systematic review

Polybrominated diphenyl ethers (PBDEs) have been extensively used as flame retardants in consumer products. PBDEs rapidly bioaccumulate in the environment, food, wild animals and humans. In this review, we investigated the harmful effects of PBDEs on humans, especially in early life, and summarised the levels of PBDEs in human biological samples (breast milk, cord blood and placentas). In addition, we described the spatiotemporal distribution of PBDEs in this review. PBDE levels in breast milk, cord blood and placentas were generally higher in North America than in other regions, such as Asia, Europe, Oceania and Africa. However, high levels of PBDEs in human biological samples were detected at e-waste recycling sites in South China, East China and South Korea. This finding suggests that newborns living in e-waste regions are exposed to high levels of PBDEs during prenatal and postnatal periods. The time trends of PBDE concentration differed according to the region. Few studies have investigated PBDE levels in humans from 1967 to 2000, but they increased rapidly after 2000. PBDE concentration peaked at approximately 2006 globally. Compared with other PBDE congeners, BDE-47, BDE-153 and BDE-209 were the major components, but the detection rate of BDE-209 was lower than those of others. Future studies should focus on determining the BDE-209 concentration, which requires the implementation of different analytical approaches. Additionally, the levels of PBDEs in human samples and the environment should be monitored, especially in e-waste recycling regions.

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Graphical abstract The figures described the spatial distribution of the lowest (Fig. a1) and highest concentration of ∑PBDE (Fig. a2) in different countries by 2006 and described the spatial distribution of the lowest (Fig. b1) and highest concentration of ∑PBDE (Fig. b2) in different countries from 2007 to 2015. All the figures indicated that the levels of PBDEs in North America were substantially higher than those in many regions of Europe, Asia, Oceania, or Africa. Comparing Fig. a1–b1 or Fig. a2–b2, increasing trends were observed in some countries, especially in some regions in China, Korea and Canada.

     

Validation of temporal and spatial consistency of facility- and speed-specific vehicle-specific power distributions for emission estimation: A case study in Beijing,China

Vehicle-specific power (VSP) has been found to be highly correlated with vehicle emissions. It is used in many studies on emission modeling such as the MOVES (Motor Vehicle Emissions Simulator) model. The existing studies develop specific VSP distributions (or OpMode distribution in MOVES) for different road types and various average speeds to represent the vehicle operating modes on road. However, it is still not clear if the facility- and speed-specific VSP distributions are consistent temporally and spatially. For instance, is it necessary to update periodically the database of the VSP distributions in the emission model? Are the VSP distributions developed in the city central business district (CBD) area applicable to its suburb area? In this context, this study examined the temporal and spatial consistency of the facility- and speed-specific VSP distributions in Beijing. The VSP distributions in different years and in different areas are developed, based on real-world vehicle activity data. The root mean square error (RMSE) is employed to quantify the difference between the VSP distributions. The maximum differences of the VSP distributions between different years and between different areas are approximately 20% of that between different road types. The analysis of the carbon dioxide (CO₂) emission factor indicates that the temporal and spatial differences of the VSP distributions have no significant impact on vehicle emission estimation, with relative error of less than 3%.

Implications: The temporal and spatial differences have no significant impact on the development of the facility- and speed-specific VSP distributions for the vehicle emission estimation. The database of the specific VSP distributions in the VSP-based emission models can maintain in terms of time. Thus, it is unnecessary to update the database regularly, and it is reliable to use the history vehicle activity data to forecast the emissions in the future. In one city, the areas with less data can still develop accurate VSP distributions based on better data from other areas.     

高速公路路面沉积物的污染特性

对湖南省长潭西高速公路不同采样点的路面沉积物进行取样分析,并检测了样品的颗粒级配、COD、重金属(Cu、Zn、Pb和Cd)和有机质。结果表明,路面沉积物主要以粒径<0.15 mm的颗粒为主;较小颗粒物中的COD含量高于较大颗粒中的COD含量;粒径在0.15 mm以下的颗粒物所含重金属Cu、Zn、Pb和Cd的浓度普遍高于所选的土壤标准值,降雨一旦形成径流将会产生严重的污染危害;沉积物中的有机质含量对重金属的吸附有一定的影响,有机质含量越高,沉积物中重金属含量相对也高。     

无机陶瓷膜处理油田采出水

针对陶瓷膜在油田采出水处理过程中操作参数的选择及污染机理进行了研究。通过现场实验,分析了不同的操作参数对膜通量的影响,陶瓷膜对含油量及悬浮物的去除效果,膜阻力组成及膜污染清洗方法。实验结果表明,在确定出水水质达到低渗透油田注水水质A1级标准条件下,陶瓷膜过滤最佳操作条件为:跨膜压差0.16 MPa、温度50℃、膜面流速5.0 m/s。同时发现,NaOH和HNO3联合清洗有助于恢复膜通量。     

臭氧催化氧化工艺深度处理印染废水

采用正交实验对催化剂NiO/γ-A12O3的制备条件进行优化,并探讨臭氧催化氧化法对于印染废水的深度处理效能.结果表明,最优的催化剂制备条件为:浸渍液浓度为3％、浸渍时间为4h、灼烧温度为450℃、灼烧时间为3h.臭氧催化氧化反应15 min时,COD浓度由84.22 mg/L降低至50.00 mg/L以下;氨氮浓度由10.88 mg/L降低至5.01 mg/L;色度去除率达到69％,明显高于单纯臭氧氧化的反应效率.     

电渗透脱水污泥干燥特性曲线及干燥模型

通过电渗透脱水技术及自然风干技术两种预处理方式降低污泥含水率,当污泥初始含水率相近时,研究经两种方式处理后污泥的干燥特性曲线,并对电渗透脱水污泥干燥特性曲线的优势情况进行探讨。在40—120℃的低温条件下,研究电渗透脱水污泥（泥饼厚度为3．5mm）的干燥特性曲线并分析其干燥特性。通过所得电渗透脱水污泥的干燥特性曲线,引人薄层污泥干燥模型进行数值分析。结果表明,在实验条件下,电渗透脱水污泥的干燥速率要优于自然风干污泥的干燥速率。随着温度的升高,电渗透脱水污泥的干燥速率随之升高,干燥到所需含水率的时间则随之减少。Logarithmic模型比其他模型更适合描述薄层电渗透脱水污泥在低温条件下的干燥特性。     

Bioremediation of Cd and carbendazim co-contaminated soil by Cd-hyperaccumulator Sedum alfredii associated with carbendazim-degrading bacterial strains

The objective of this study was to develop a bioremediation strategy for cadmium (Cd) and carbendazim co-contaminated soil using a hyperaccumulator plant (Sedum alfredii) combined with carbendazim-degrading bacterial strains (Bacillus subtilis, Paracoccus sp., Flavobacterium and Pseudomonas sp.). A pot experiment was conducted under greenhouse conditions for 180 days with S. alfredii and/or carbendazim-degrading strains grown in soil artificially polluted with two levels of contaminants (low level, 1 mg kg^?1 Cd and 21 mg kg^?1 carbendazim; high level, 6 mg kg^?1 Cd and 117 mg kg^?1 carbendazim). Cd removal efficiencies were 32.3–35.1 % and 7.8–8.2 % for the low and high contaminant level, respectively. Inoculation with carbendazim-degrading bacterial strains significantly (P?<?0.05) increased Cd removal efficiencies at the low level. The carbendazim removal efficiencies increased by 32.1–42.5 % by the association of S. alfredii with carbendazim-degrading bacterial strains, as compared to control, regardless of contaminant level. Cultivation with S. alfredii and inoculation of carbendazim-degrading bacterial strains increased soil microbial biomass, dehydrogenase activities and microbial diversities by 46.2–121.3 %, 64.2–143.4 %, and 2.4–24.7 %, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed that S. alfredii stimulated the activities of Flavobacteria and Bradyrhizobiaceae. The association of S. alfredii with carbendazim-degrading bacterial strains enhanced the degradation of carbendazim by changing microbial activity and community structure in the soil. The results demonstrated that association of S. alfredii with carbendazim-degrading bacterial strains is promising for remediation of Cd and carbendazim co-contaminated soil.     

Rubber and pulp plantations represent a double threat to Hainan's natural tropical forests

Hainan, the largest tropical island in China, belongs to the Indo-Burma biodiversity hotspot and harbors large areas of tropical forests, particularly in the uplands. The Changhua watershed is the cradle of Hainan's main river and a center of endemism for plants and birds. The watershed contains great habitat diversity and is an important conservation area. We analyzed the impact of rubber and pulp plantations on the distribution and area of tropical forest in the watershed, using remote sensing analysis of Landsat images from 1988, 1995 and 2005. From 1988 to 1995, natural forest increased in area (979-1040?sq?km) but decreased rapidly (763?sq?km) over the next decade. Rubber plantations increased steadily through the study period while pulp plantations appeared after 1995 but occupied 152?sq?km by 2005. Rubber and pulp plantations displace different types of natural forest and do not replace one another. Because pulp is not as profitable as rubber and existing pulp processing capacity greatly exceeds local supply, considerable pressure exists on remaining upland forests. We recommend for future management that these plantation forests be reclassified as 'industrial', making a clear policy distinction between natural and industrial forestry. Additionally, the local government should work to enforce existing laws preventing forest conversion on marginal and protected areas.     

A human health risk assessment of rare earth elements in soil and vegetables from a mining area in Fujian Province,Southeast China

Contaminated food through dietary intake has become the main potential risk impacts on human health. This study investigated concentrations of rare earth elements (REEs) in soil, vegetables, human hair and blood, and assessed human health risk through vegetables consumption in the vicinity of a large-scale mining area located in Hetian Town of Changting County, Fujian Province, Southeast China. The results of the study included the following mean concentrations for total and bio-available REEs of 242.92 ± 68.98 (135.85–327.56) μg g⁻¹ and 118.59 ± 38.49 (57.89–158.96) μg g⁻¹ dry weight (dw) in agricultural soil, respectively, and total REEs of 3.58 ± 5.28 (0.07–64.42) μg g⁻¹ dw in vegetable samples. Concentrations of total REEs in blood and hair collected from the local residents ranged from 424.76 to 1274.80 μg L⁻¹ with an average of 689.74 ± 254.25 μg L⁻¹ and from 0.06 to 1.59 μg g⁻¹ with an average of 0.48 ± 0.59 μg g⁻¹ of the study, respectively. In addition, a significant correlation was observed between REEs in blood and corresponding soil samples (R² = 0.6556, p < 0.05), however there was no correlation between REEs in hair and corresponding soils (p > 0.05). Mean concentrations of REEs of 2.85 (0.59–10.24) μg L⁻¹ in well water from the local households was 53-fold than that in the drinking water of Fuzhou city (0.054 μg L⁻¹). The health risk assessment indicated that vegetable consumption would not result in exceeding the safe values of estimate daily intake (EDI) REEs (100−110 μg kg⁻¹ d⁻¹) for adults and children, but attention should be paid to monitoring human beings health in such rare earth mining areas due to long-term exposure to high dose REEs from food consumptions.     

Occurrence, possible sources, and temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans in water and sediment from the lower Yangtze River basin, Jiangsu and Shanghai areas of Eastern China

The concentrations, compositional profiles, and possible sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) in water column and surface sediment samples from the lower reaches of the Yangtze River were investigated, and the potential risks posed by these chemicals were evaluated. Concentrations of the 17 2,3,7,8-substituted PCDD/PCDF in the water and sediment samples ranged from 0.45 to 10.0 pg TEQ/L (mean 2.34 pg TEQ/L) and from 0.31 to 51 pg TEQ/g dw (mean 5.25 pg TEQ/g dw), respectively. Water and sediments from the Nanjing–Nantong sections of the Yangtze River were found to have elevated PCDD/PCDF levels, and the PCDD/PCDF TEQ concentrations in 13 sediment samples exceeded the probable effect levels (PEL), above which adverse biological effects are likely. Multivariate statistical analysis indicated that the principal PCDD/PCDF contamination source for the water and sediment was the production and use of pentachlorophenol (PCP) or sodium pentachlorophenate (PCP-Na). PCDD/PCDF concentrations were stable over time near the Yangtze River Estuary but had increased sharply in recent decades in the Nanjing–Nantong section, which will have been related to the growth in industrial activities and other anthropogenic PCDD/PCDF sources. Total organic carbon (TOC) and PCDD/PCDF concentrations correlated significantly (R?=?0.474, P?<?0.01), suggesting that TOC plays an important role in the transport and re-distribution of PCDD/PCDF in the Yangtze River basin.