杀虫单降解菌的筛选分离与降解特性研究

从农药厂废水排放沟污泥中分离到一株对杀虫单有较强降解能力的菌株LY－4,经鉴定为巨大芽孢杆菌（Bacillus megaterium)。其生长的最适pH为7,最适温度为30℃。该菌对杀虫单有很强的耐受性,在杀虫单浓度ρ＝5000mg/L时,仍能较好地生长并发挥降解作用。当杀虫单初始浓度高于一定值时,一定量的菌剂对杀虫单的降解率随底物浓度的提高而降低,而绝对去除量则随底物浓度的提高而提高。与不加菌的对照相比,加入LY－4后,可使杀虫单浓度在很短的时间内降到很低的水平。图5表1参6     

污染土壤添加有机物质对黑麦草吸收铜的影响

研究了泥炭和堆肥对铜污染土壤盆栽黑麦草吸收铜状况的影响。结果表明 ,黑麦草地上、地下部含铜量皆随土壤污染水平提高而增加 ,地下部的增幅远大于地上部 ;添加有机物质明显降低了黑麦草地上、地下部的含铜量 ,平均降幅近 3 0 %。泥炭降低黑麦草地上、地下部含铜量的作用随土壤污染水平的提高而逐渐变小 ,而堆肥的作用至重度污染水平仍较明显 ;在近 4 0 0mg/kg铜污染水平上 ,有机物质表现出最佳降低植株铜吸收量的效果。有机物质的控制作用与土壤pH有关 ,并在 3茬黑麦草的试验期间内得以维持     

Histopathological changes in zebrafish embryos exposed to DLPCBs extract from Zhanjiang coastal sediment

Dioxin-like polychlorinated biphenyls (DLPCBs) are ubiquitous persistent pollutants that cause adverse effects in many environmental organisms. DLPCBs in marine sediments can be absorbed by benthic organisms, bioaccumulate, and biomagnify through the food chain and threaten animal and human health. There are no reports of DLPCBs concentrations in the Zhanjiang Gulf seabed. This study was designed to investigate the concentration of DLPCBs in the Zhanjiang coastal sediment and histopathological changes in zebrafish (Diano rerio) embryos exposed to environmentally relevant concentrations of DLPCBs. Of the five sites selected, two sites TS and JSW contained DLPCBs at concentrations of 0.08 and 22.54 ng/g dry sediment, respectively. Two groups of zebrafish embryos were used. One group was exposed to 3.75, 7.5, 15, 30, and 60 mg/ml of DLPCBs extracted from the sediments sampled from the TS site and the second group to 4.375, 8.75, 17.5, 35, and 70 mg/ml of DLPCBs from JSW site from 0.75 h post-fertilization (hpf) to 96 hpf. The zebrafish exposed to 60 and 70 mg/ml of DLPCBs at 96 hpf displayed gross histopathological changes with cardiac lesions including pericardial edema being the most deleterious. Other changes observed were hydropic degeneration of gill filaments and hepatocytes, loss of intestinal folds, and uninflated swim bladder. It appears that only a few sites of the Zhanjiang gulf are contaminated with DLPCBs. This is the first report of histopathological changes in the gills, hepatocytes, intestines, heart, and the swim bladder in zebrafish embryos exposed to DLPCBs from a coastal sediment. Further studies with sampling at different stages of development are required to identify which organ/tissue is most sensitive to DLPCBs.     

Distribution,sources, and ecological risk assessment of SVOCs in surface sediments from Guan River Estuary,China

The contamination of semi-volatile organic compounds (SVOCs) in the surface sediments of the Guan River Estuary, China was fully investigated. Total concentrations of 56 species of SVOCs ranged from 132 to 274 ng/g with an average of 186 ng/g (dry weight). Polycyclic aromatic hydrocarbon (PAH) concentrations were positively correlated with clay content and negatively correlated with sediment grain size. Source identification indicated that PAHs originated mainly from pyrolytic sources. However, intense ship traffic in the estuary may provide sources of petrogenic PAHs. Organochlorine pesticides (OCPs) mainly originated from direct input of dichlorodiphenyltrichloroethanes (DDTs) during some industrial processes. The SVOC concentrations were also compared with International Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated that negative biological impacts may originate from high concentrations of FLO, p,p′-DDE, and total DDTs.     

Diurnal concentrations variations,size distributions for ambient air particles and metallic pollutants (Cr,Mn, Ni,Cd, Pb) during summer season at a traffic area

This study characterized and discussed particulate ambient air particulate concentrations and seasonal variations for PM₁₈, PM₁₀, PM_2.5, and PM₁ during June 2013–July 2013 at this traffic sampling site. In addition, this study also characterized the ambient air particulates size distributions by using MOUDI-100S4 sampler to collect 1-day the ambient suspended particles (PM₁₈, PM₁₀, PM_2.5, and PM₁) at this sampling site. In addition, the study also showed that the main pollutants contributions were from traffic and residual areas. As for the pollutants seasonal concentrations variations, the results indicated that the average particle concentrations orders were all displayed as daytime?>?nighttime for PM₁₈, PM₁₀, PM_2.5 and PM₁ at this characteristic sampling site. The results further indicated that the mean highest of metal concentrations in this study indicated that the average metal concentration were all displayed as Mn?>?Cr?>?Ni?>?Pb?>?Cd for PM₁₈, PM₁₀, PM_2.5 and PM₁ on daytime and nighttime at this characteristic sampling site.     

Assessment of trace element contamination in sediment cores from the Pearl River and estuary,South China: geochemical and multivariate analysis approaches

Twenty-four major and trace elements and the mineralogical composition of four sediment cores along the Pearl River and estuary were analyzed using ICP-AES, ICP-MS, and X-ray diffraction (XRD) to evaluate contamination levels. The dominant minerals were quartz, kaolinite, and illite, followed by montmorillonite and feldspars, while small amounts of halite and calcite were also observed in a few samples. Cluster analysis (CA) and principal component analysis (PCA) were performed to identify the element sources. The highest metal concentrations were found at Huangpu, primarily due to wastewater treatment plant discharge and/or the surreptitious dumping of sludge, and these data differed from those of other sources. Excluding the data from Huangpu, the PCA showed that most elements could be considered as lithogenic; few elements are the combination of lithogenic and anthropogenic sources. An antagonistic relationship between the anthropogenic source metals (K, Ba, Zn, Pb, Cd, Ag, Tl, and U) and marine source metals (Na, Mg, Ti, V, and Ca) was observed. The resulting normalized Al enrichment factor (EF) indicated very high or significant pollution of Cd, Ag, Cu, Zn, Mo, and Pb at Huangpu, which may cause serious environmental effects. Conflicting results between the PCA and EF can be attributed to the background values used, indicating that background values must be selected carefully.     

Characteristics and assessment of phthalate esters in urban dusts in Guangzhou city, China

Phthalate esters (PAEs) were examined in indoor and outdoor dust samples from the subtropical city of Guangzhou, China. The ∑(16)PAEs concentrations ranged from 121 to 3,223 μg g(-1) dust, with the median concentration of 840 μg g(-1) dust. Significantly higher concentrations of PAEs in dust samples were found in offices where electrical and electronic devices, carpet pads, and office furniture were widely used. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs in indoor and outdoor dust samples, and accounted for >96.8% and >93.1% of the ∑(16)PAEs concentrations, respectively. The median daily inhalation exposure of ∑(16)PAEs were 3.53 and 0.247 μg kg(-1) body weight day(-1), and at the 95(th) percentile were 7.62 and 0.530 μg kg(-1) body weight day(-1), up on the measured concentrations and estimated dust ingestion rates, respectively, for toddles and adults. The ubiquitous distribution of PAEs as noted in this study suggests the need for detailed assessment of PAEs concentrations using more sites and to further investigate the factors influencing PAEs exposure in China.     

Comparative assessments of VOC emission rates and associated health risks from wastewater treatment processes

With the growing concern regarding emission of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs), the relationship between the VOC emission rates and the associated public health risks has been rarely discussed. The objective of this study was to examine and compare the VOC emission rates and cancer and non-cancer risks by inhalation intake, using a municipal WWTP in China as an example, with respect to the effects of treatment technologies, VOC species, and seasonal variation. Given the treatment technology considered, the emission rates of VOCs in this study were estimated by means of mass balance or calculated on the molecular level. From the viewpoints of both emission rates and cancer and non-cancer risks, sedimentation was the treatment technology with the highest health risks to the workers. Slightly lower VOC emission rates and health risks than those for sedimentation were observed in anaerobic treatment. Although the aeration significantly enhanced the VOC emission rates in the aerobic treatment process, the associated health risks were limited due to the low VOC concentrations in the gas phase, which were likely attributed to the strong mixing and dilution with fresh air by aeration. Amongst the VOCs investigated, benzene was the VOC with both a relatively high emission rate and health risk, while trichloroethylene possessed a high emission rate but the lowest health risk. Without strong interfacial aeration and turbulence between the water and atmosphere, the effects of treatment technology and seasonal variation on the health risks might be connected to the VOC emission rates, while the effect of VOC species depended considerably on the respective cancer slope factors and reference concentrations; the employment of aeration provided a different conclusion in which the emission rates were enhanced without a significant increase in the related cancer risks. These findings can provide insight into future health risk management and reduction strategies for workers in WWTPs.     

Characteristic, composition, and sources of TSP investigated by HRTEM/EDS and ESEM/EDS

Total suspended particle (TSP) collected at the fifth floor of House Dust in Hunan University, China, was analyzed in terms of microscopic morphology and chemical composition. The fine particles (50?nm-2?μm) in the TSP were analyzed by a high-resolution transmission electron microscope equipped with an energy-dispersive X-ray analyzer (HRTEM/EDS). Results showed that the particles were in shapes of plate, irregular and agglomerate. Based on EDS results, these fine particulate matter was primarily composed of Fe-rich (35.82-61.29%), Ca-rich (30.18-36.77%) and Si-rich (18.95-32.28%) particles. Other elements mainly including Mg (0.47-4.97%), Al (0.45-14.57%), S (0.45-4.73%), K (1.13-2.13%) and Zn (0.67-3.85%) were also observed. The sources analysis indicated that the HRTEM particles mainly originated from coal combustion, traffic emission, vehicles exhaust emission and fugitive soil or cement particulate matter. The coarse particles (4-50?μm) were detected by environmental scanning electron microscopy coupled with energy-dispersive X-ray detector (ESEM/EDS). Based on a simple algorithm, ESEM particles were categorized into five groups: C-bearing (46.15%, 67% and 86.98%), Si + Ca-bearing (21.48?+?11.80%, 16.51?+?10.81% and 16.32?+?10.62%), Si + Al-bearing (20.06?+?12.40%, 20.16?+?11.22% and 15.31?+?11.25%), Si-bearing (34.40%, 26.92% and 27.15%) particles and aggregates, most of which exhibit obvious crystalline structure, and these ESEM particles mainly derived from vehicles exhaust emission, coal combustion, soil, and biomass burning, while the aggregates are indicative of atmospheric reaction progress. HRTEM/EDS and ESEM/EDS are mutual complementary in analyzing the characteristic and determining the sources of TSP.