Estrogenic and dioxin-like compounds in sediment from Zierikzee harbour identified with CALUX assay-directed fractionation combined with one and two dimensional gas chromatography analyses

The identity of compounds responsible for estrogenic and dioxin-like activities in sediment from the harbour of the small town Zierikzee in Zeeland, The Netherlands, was investigated using a bioassay directed fractionation approach with the in vitro estrogen and dioxin responsive reporter gene assays ER- and DR-CALUX. For identification of compounds exhibiting activity in the bioassays, either one or two-dimensional GC in combination with quadrupole (MSD), ion trap (ITD) or time-of-flight mass spectrometric detection (ToF-MS) was used, depending on the biological and chemical characteristics and the complexity of the fractions. The natural estrogenic hormone 17-β-estradiol and its metabolite estrone were identified with GC–ITD as the main contributors to the estrogenic activity. After successive rounds of fractionation, the dioxin-like activity could be explained by the presence of various polycyclic aromatic hydrocarbons identified with GC–MSD and two-dimensional comprehensive GC × GC–ToF-MS. Some estrogenic activity of a relatively non-polar nature remained unidentified.     

Assessment of Coarse Sediment Mobility in the Black Canyon of the Gunnison River,Colorado

The Gunnison River in the Black Canyon of the Gunnison National Park (BCNP) near Montrose, Colorado is a mixed gravel and bedrock river with ephemeral side tributaries. Flow rates are controlled immediately upstream by a diversion tunnel and three reservoirs. The management of the hydraulic control structures has decreased low-frequency, high-stage flows, which are the dominant geomorphic force in bedrock channel systems. We developed a simple model to estimate the extent of sediment mobilization at a given flow in the BCNP and to evaluate changes in the extent and frequency of sediment mobilization for flow regimes before and after flow regulation in 1966. Our methodology provides a screening process for identifying and prioritizing areas in terms of sediment mobility criteria when more precise systematic field data are unavailable. The model uses the ratio between reach-averaged bed shear stress and critical shear stress to estimate when a particular grain size is mobilized for a given reach. We used aerial photography from 1992, digital elevation models, and field surveys to identify individual reaches and estimate reach-averaged hydraulic geometry. Pebble counts of talus and debris fan deposits were used to estimate regional colluvial grain-size distributions. Our results show that the frequency of flows mobilizing river bank sediment along a majority of the Gunnison River in the BCNP has significantly declined since 1966. The model results correspond well to those obtained from more detailed, site-specific field studies carried out by other investigators. Decreases in the frequency of significant sediment-mobilizing flows were more pronounced for regions within the BCNP where the channel gradient is lower. Implications of these results for management include increased risk of encroachment of vegetation on the active channel and long-term channel narrowing by colluvial deposits. It must be recognized that our methodology represents a screening of regional differences in sediment mobility. More precise estimates of hydraulic and sediment parameters would likely be required for dictating quantitative management objectives within the context of sediment mobility and sensitivity to changes in the flow regime.     

Characteristics and distribution of phosphorus in surface sediments of a shallow lake

Phosphorus ( P ) in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment. The mobility and bioavailability of P primarily depend on the contents of different P forms, which in turn depend on the sedimentary environment.Here, sediment samples from Baiyangdian (BYD) lake were collected and measured by the Standards, Measurements, and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) to characterize different P forms and their relationships with sediment physicochemical properties. The P content in the sediments varied in different areas and had haracteristics indicative of exogenous river input. Inorganic P (334–916 mg/kg) was the dominant form of P . The 31P NMR results demonstrated that orthophosphate monoesters (16–110 mg/kg), which may be a source of P when redox conditions change, was the dominant form of organic P (20–305 mg/kg). The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities, and the regions affected by exogenous river input had a higher content of P and a higher risk of P release. Principal component analysis indicated that P bound to Fe, Al, and Mn oxides and hydroxides (NaOH-P) and organic P were mainly derived from industrial and agricultural pollution, respectively. Redundancy analysis indicated that increases in pH lead to the release of NaOH-P. Organic matter plays an important role in the organic P biogeochemical cycle, as it acts as a sink and source of organic P .     

Spatial and temporal dynamics of microbial community composition and factors influencing the surface water and sediments of urban rivers

The temporal and spatial characteristics of urban river bacterial communities help us understand the feedback mechanism of bacteria to changes in the aquatic environment.The Fuhe River plays an important role in determining the water ecological environment of Baiyangdian Lake.16S rRNA gene sequencing was used to study the microbial distribution characteristics in the Fuhe River in different seasons.The results showed that some environmental factors of the surface water (ammonia nitrogen (NH_...     

Integrated biomonitoring assessment of the Lesina Lagoon (Southern Adriatic Coast, Italy): preliminary results

An integrated biomonitoring program for marine and coastal ecosystems quality assessment combines the chemical characterization of a site with the evaluation of the possible structure alterations of its living communities. This can be considered an useful tool for better identifying the summarized effects of all the components interacting with the biota. Such an integrated procedure was carried out for the assessment of the quality of the Lesina Lagoon (Southern Adriatic Coast, Italy). The water parameters levels showed a high primary production (2-6 μg l^-1); the sediment and pore water toxicity bioassays recorded a low or moderate diffused toxicity. Besides, the benthic meiofauna community structure was characterized by prevalent Nematoda taxa with a homogeneous spatial distribution. On these basis, the Lesina Lagoon seems to be characterized by a prevalent organic pollution mainly related to agricultural and zootechnical activities which, due to the lagoon's conformation, presents a homogeneous spatial distribution.     

Environmental concerns for marina planning in the Gulf of Suez

This paper presents a case study where numerical modelling was utilized for the first time to estimate shoreline changes during the planning of a private pleasure marina in the Gulf of Suez. The study was made to compliment an environmental impact assessment study (EIA) requested by the Egyptian Environmental Affairs Agency (EEAA). The paper presents data collected during two surveys and the results of the numerical model. The impact of the marina on the sediment budget was investigated using the GENESIS one-line program. One of the main reasons for the study was to confirm that the choice of the marina location ensured minimum erosion of the shoreline. In the model, the sediment transport calibration constants were determined using the results of two surveys. The choice of the formula is discussed in the paper. Two locations for the marina were tested against minimum erosion at the down drift side of the marina. This study was performed in close co-ordination with the EEAA and several solutions were suggested to minimize the expected accretion before the final location was approved.     

桃浦河底泥COD_(Cr)和NH_3-N的分布特征浅析

根据上海市桃浦河的河道形态和地貌特征,共设计和采集了15个柱样,在对其进行CODCr、NH3-N系统测定分析的基础上,得出以下结论:(1)桃浦河底泥已受到严重污染,CODCr、NH3-N的平均含量分别超过参照标准值(CODCr9699.6mg/kg,NH3-N78.79mg/kg)1.1～10倍和1～5_8倍,污染最严重的是真大路桥到沪嘉高速公路段;其次是环镇北路桥到陈太路存瑞桥段,云岭东路桥到中科化工厂桥段,杨柳青路桥到北石路桥段。(2)垂直分布呈现由下而上污染加重的趋势,表明现代污染日趋严重。(3)不同河段污染程度出现差异主要与其所处周围环境的排污有关。(4)基于桃浦河底泥污染程度的不同,在底泥疏浚时应予以区别对待。     

Chemical contamination and sediment toxicity along the coast of Corsica

Trace metals (Cd, Pb, Cu, Cr, Ni, Co, Zn, Hg, As, Mn, Al, Fe, and Li) and organic compounds (PCBs, PAHs, lindanes, and DDT and its degradation products) were measured in coastal sediment samples from 27 sites in lagoons and along coastal areas of Corsica. An oyster embryo bioassay evaluated the toxicity of sediments from sites in three coastal lagoons (Urbino, Diane, and Biguglia) and the west coast of Cape Corsica. Despite contamination levels generally lower than those in other Mediterranean coastal areas, contamination is found in specific sites in Corsica and includes natural arsenic contamination on the east coast, insecticide pollution (persistent lindane and DDT) in many areas, both cadmium and lead contamination around Sagone, general contamination of both main harbours (Bastia and Ajaccio) and their surrounding areas, and asbestos mining residues in western Cape Corsica. Monitoring development of Crassostrea gigas embryos showed toxic effects at sites near a factory on Cape Corsica, with up to 100% mortality of larvae, and lower levels of toxicity at Sagone (44% mortality) and in the three coastal lagoons (up to 28% mortality). Results of this regional study show the need for further monitoring to understand the environmental issues facing the Corsican coast.     

Impact of four-dimensional seismic and production activities on the mangrove systems of the Niger Delta, Nigeria

Reconnaissance survey and laboratory appraisal of the mangrove system in seven communities in the Niger Delta (Nigeria) endangered by seismic and production operations revealed several alterations of soil, sediment, and vegetation. Hydrocarbon content in the range of 0.3-1.1 mg/100 g was extracted within the proximities of spill sources and seismic lines. The prospect area covered by our investigation was characterized by a mixed mangrove forest dominated by Rhizophora racemosa. It was observed that the construction of the seismic lines was responsible for the vegetal disorientation recurrent in the area. The grass, Paspalum vaginatum, and the saltwater fern, Acrostichum aureum, were found at the fringe of most dredge spoils. The characteristic tidal inundation which increases mobility of the substrate, salinity fluctuation, and anoxia may also have contributed, at least in part, to the observed despoliation of some of these species found within the vicinities of the seismic lines and hydrocarbon percolation. Extensive revegetation program is recommended to ensure an effective restoration process of this ecologically fragile zone.     

Evaluation of dilute hydrochloric acid and acid ammonium oxalate as extractants for some heavy metals from Nile River sediments

The suitability of a 0.5 M HCl solution for extraction of Fe, Mn, Cd, Co, Cu, Pb, and Zn from Nile River sediments was evaluated by comparing its effectiveness with that of conventional acid ammonium oxalate (Tamm's solution) and aqua regia extraction solutions. The present study has shown that although the extraction data indicate that both 0.5 M HCl and acid ammonium oxalate solutions are able to extract heavy metals simultaneously from the adsorbed, organic, and precipitated phases of Nile sediments, the 0.5 M HCl solution is preferred. It provides a rapid, reliable, and inexpensive method of measuring environmentally mobile metal concentrations in the aquatic sediments. From an analytical chemistry point of view, the 0.5 M HCl extracts do not clog the atomizer of the spectrophotometer. Extraction with dilute HCl solution obviates the need to use chemicals, some of which are toxic or not available readily as a high-purity grade. A standard extraction method should be relatively simple, to conduct a routine analysis of large numbers of sediment samples, yet at the same time it should provide sufficient information for assessment of the environmental impact of particulate metals. Therefore, extraction with 0.5 M HCl solution is very suitable for heavy-metal pollution monitoring in the Nile River