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281.
282.
Zhang R Wu F Liu C Fu P Li W Wang L Liao H Guo J 《Environmental pollution (Barking, Essex : 1987)》2008,152(2):366-372
In this study, the characteristics of organic phosphorus (Po) fractions in sediments of six lakes from the middle and lower reaches of Yangtze River region and Southwestern China Plateau, China were investigated using a soil Po fractionation scheme, and the relationships between Po, inorganic phosphorus (Pi) and pollution status were also discussed. The results show that the rank order of Po fractions was: residual Po>HCl-Po>fulvic acid-P>humic acid-P>NaHCO3-Po, with their average relative proportion 8.7:4.6:3.2:2.1:1.0. Po fractions, especially nonlabile Po, were significantly correlated with organic matter, Po and NaOH-Pi. Different distribution patterns of P fractions were observed in those two different regions. Po fractions in the heavily polluted sediments were higher than those in moderately and no polluted sediments, it is suggested that Po should be paid more attention in the lake eutrophication investigation. 相似文献
283.
284.
Atmospheric deposition of nutrients within agricultural watersheds has received scant attention and is poorly understood compared to nutrient transport in surface and subsurface water flow pathways. Thus, we determined the deposition of phosphorus (P), nitrogen (N), and sediment in a mixed land use watershed in south-central Pennsylvania (39.5 ha; 50% corn–wheat–soybean rotation, 20% pasture, and 30% woodland), in comparison with stream loads at several locations along its reach between 2004 and 2006. There was a significant difference in deposition rates among land uses (P < 0.05) with more P and N deposited on cropland (1.93 kg P and 10.71 kg N ha−1 yr−1) than pasture (1.10 kg P and 8.06 kg N ha−1 yr−1) and woodland (0.36 and 2.33 kg N ha−1 yr−1). Although not significant, sediment showed the same trends among land uses. A significant relationship was found between P in deposition and P in soil <10-m away from the samplers suggesting much of the deposited sample was derived from local soil. Samplers adjacent to the stream channel showed deposition rates (1.64 kg P and 8.83 kg N ha−1 yr−1) similar to those on cropland. However, accounting for the surface area of the stream, direct deposition of P, N, and sediment probably accounted for <3% of P and <1% of N and sediment load in stream flow from the watershed (1.41 kg P, 27.09 kg N, and 1343 kg sediment ha−1 yr−1 at the outlet). This suggests that strategies to mitigate nutrient and sediment loss in this mixed-land use watershed should focus on runoff pathways. 相似文献
285.
为了解祊河河流沉积物重金属情况,以祊河橡胶坝至沂蒙路大桥段为主研究对象,对河段内8个断面沉积物的3个指标(Cu、Zn、Cd)进行监测调查,参照国内有关标准,建立了适合该区域的沉积物污染评价标准,主要运用潜在生态危害指数法和内梅罗法标准指数法对检测结果进行生态风险和污染程度评价。结果表明:祊河橡胶坝至沂蒙路大桥段沉积物重金属生态危害指数高达3418.5,内梅罗污染指数为6.95,为重度污染,说明祊河沉积物重金属污染非常严重。 相似文献
286.
The associated industrial and urban developments are located to a large extent along the Laizhou Bay, Bohai Sea coastal and
raw sewage is often discharged into near shore waters with little treatment. To find out chemical characteristics and pollution
source of the petroleum related contaminations in sediments near the major drainage outfalls located in the coastal, in this
study, 10 surface sediment samples were collected during June. Sediment samples were extracted by organic solvents, separated
by silica gel column chromatography and the concentrations and the profiles of n-alkane, biomarker and PAH in sediments were analyzed by gas chromatography-mass selective detector (GC-MSD). The use of several
molecular markers and related indexes derived for n-alkane and PAHs has been proposed for assessing the relative contributions to the environment of hydrocarbon sources. As
a result, n-alkanes reflect that the sea area of paper mill (Station ZZ08) is dominated by vascular plant. DY petroleum oil field and
outer shore of the paper mill (Station ZZ02) have some degrees of petroleum related hydrocarbon contamination. Whereas the
contamination of the sea area of TH River may be ascribed to different sources such as territorial non-point pollution source,
domestic sewages, and stormwater runoff. Judged by their PAH ratios, the sediments near the paper mill (Station ZZ02) and
the outer station of the oil field (Staion TH2) were pyrolytic. The estuary of Tiao River including the inner Station THX,
TH10 and TH05 are petrogenic. The marine sediment near DY drainage outfall may have a mixture source of PAH both pyrolytic
and petrogenic. 相似文献
287.
陈秋兰 《环境监测管理与技术》2019,31(3):49-52
沉积物样品用乙腈-柠檬酸缓冲溶液提取后经HLB-SPE柱净化,采用LC-MS/MS法在MRM模式下测定17种磺胺类和4种四环素类抗生素,通过优化测定条件,使方法在0. 500μg/kg~100μg/kg范围内线性良好。方法检出限为0. 15μg/kg~1. 2μg/kg,2个质量比水平的加标回收率为44. 1%~125%,试验5次结果的RSD 16. 0%。将该方法用于测定厦门近岸海域沉积物中抗生素,共有6种磺胺类和4种四环素类抗生素检出,测定值为0. 3μg/kg~26. 2μg/kg。 相似文献
288.
Lakes are an important component of terrestrial carbon cycling. As the trend of eutrophication in many lakes continues, the mechanisms of organic carbon(OC) burial remain unclear. This paper aims to understand the distribution of OC and the effect of trophic level changes on OC burial in Chaohu Lake, a shallow eutrophic lake located in the lower reaches of the Yangtze River, SE China. Two hundred and one surface sediment samples(0–20 cm) and 53 subsurface samples(150–200 cm) from the lake were collected.The OC accumulation rates(OCARs) are relatively low, with an average of 10.01 g/m2/year in the surface sediments. The spatial distribution of the OCARs is similar to that of allochthonous OC. The difference in total phosphate(TP) content between the surface and subsurface sediments(ΔTP) is significantly correlated with the autochthonous OC,suggesting that TP loading is a critical limiting nutrient for the lake's primary productivity.It is concluded that allochthonous OC is the dominant source of total OC in surface sediments compared to autochthonous OC. The primary productivity of Lake Chaohu increased due to increasing nutrient loading. However, the autochthonous OC contributed11% of the total OC in the surface sediments. This could be ascribed to strong mineralization in the water column or surface sediments. 相似文献
289.
Mohammed Rasheed Christian Wild Carin Jantzen Mohammed Badran 《Chemistry and Ecology》2013,29(1):13-20
In situ and laboratory incubation experiments in a fringing reef in the Gulf of Aqaba were performed to study degradation rates of particulate organic matter in reef sediments. Coral mucus, clam eggs, and zooxanthellae were used as model particulate organic compounds for these experiments. Aerobic and anaerobic mineralization rates were calculated by dissolved inorganic carbon (DIC) and O2 fluxes from the sediments under different particulate organic matter additions. Fast enhancement (approximately twofold) of O2 and DIC fluxes were found with the addition of coral mucus and clam eggs compared with control incubations without addition. Most of the degradation is believed to have occurred anaerobically rather than aerobically (DIC:O2 ratios were 4.3–28.1). Higher degradation rates of coral mucus and clam eggs were estimated in carbonate sediment than in silicate sediment (1.2–1.6-fold), which was attributed to the different physical and chemical properties of both sediments. Our study shows the significance of the reef sediment as a suitable site for microbial degradation of particulate organic material excreted from different reef community organisms. This may increase the regeneration of nutrients in the reef environment necessary to sustain high biological productivity. 相似文献
290.
Polycyclic aromatic hydrocarbons (PAHs) concentrations were determined in sediments and three types of wetland plants collected from the intertidal flats in the Chongming wetland. The concentration of total PAHs in sediments ranged from 38.7 to 136.2 ng g−1. Surface sediment concentrations were higher in regions with plant cover than in bare regions. Rhizome-layer sediments (56.8-102.4 ng g−1) contained less PAHs than surface sediments (0-5 cm). Concentrations of PAHs in plant tissues ranged from 51.9 to 181.2 ng g−1, with highest concentrations in the leaves of Scirpus. Most of the PAHs in the leaves and other plant tissues were low molecular weight compounds (LMW, 2-4 rings), and a similar distribution pattern of PAHs in different types of plants was also observed. Source analysis indicated that plants and sediments both came from pyrogenic sources, but plants had additional petroleum contamination. The low ratio of benzo[a]anthracene over chrysene suggests that the wetland PAHs came mainly from long-distance atmospheric transportation. Significant bioaccumulation of PAHs from the sediments into plants was not observed for high molecular weight PAHs (HMW, 5-6 rings) in Chongming wetland. The small RCFs (root concentration factor from sediments) for HMW PAHs and large RCFs for LMW PAHs suggested that roots accumulated LMW PAHs selectively from sediments in Chongming wetland. 相似文献