Ultracentrifugation as a direct method to concentrate viruses in environmental waters: virus-like particle enumeration as a new approach to determine the efficiency of recovery

Some health important enteric viruses are considered to be emerging waterborne pathogens and so the improvement of detection of these viruses in the aquatic environment is one of the most important steps in dealing with these pathogens. Since these viruses may be present in low numbers in water, it is necessary to concentrate water samples before viral detection. Although there are several methods to concentrate viruses in environmental waters, all present some drawbacks and consequently the method should be chosen that, despite its limitations, is adequate to achieve the aim of each study. As the effectiveness of the concentration methods is evaluated by determining the efficiency of viral recovery after concentration, it is important to use a simple and effective approach to evaluate their recovery efficiency. In this work ultracentrifugation, usually used as a secondary step for virus concentration, was evaluated as the main method to concentrate directly viruses in environmental water samples, using the microscopic enumeration of virus-like particles (VLP) as a new approach to estimate the efficiency of recovery. As the flocculation method is currently employed to concentrate viruses in environmental waters, it was also used in this study to assess the efficiency of the ultracentrifugation as the main viral concentration method in environmental waters. The results of this study indicate that ultracentrifugation is an adequate approach to concentrate viruses directly from environmental waters (recovery percentages between 66 and 72% in wastewaters and between 66 and 76% in recreational waters) and that the determination of VLP by epifluorescence microscopy is a simple, fast and cheap alternative approach to determine the recovery efficiency of the viral concentration methods.     

Visualisation of natural aquatic colloids and particles -- a comparison of conventional high vacuum and environmental scanning electron microscopy

The applicability of environmental scanning electron microscopy (ESEM; imaging of hydrated samples) and conventional high vacuum scanning electron microscopy (SEM; imaging of dried samples at high vacuum) for the observation of natural aquatic colloids and particles was explored and compared. Specific attention was given to the advantages and limitations of these two techniques when used to assess the sizes and morphologies of complex and heterogeneous environmental systems. The observation of specimens using SEM involved drying and coating, whereas ESEM permitted their examination in hydrated form without prior sample preparation or conductive coating. The two techniques provided significantly different micrographs of the same sample. SEM provided sharper images, lower resolution limits (10 nm or lower), but more densely packed particles, suggesting aggregation, and different morphological features than ESEM, suggesting artefacts due to drying. ESEM produced less easily visualised materials, more complex interpretation, slightly higher resolution limits (30-50 nm), but these limitations were more than compensated for by the fact that ESEM samples retained, at least to some extent, their morphological integrity. The results in this paper show that SEM and ESEM should be regarded as complementary techniques for the study of aquatic colloids and particles and that ESEM should be more widely applied to aquatic environmental systems than hitherto.     

Morphology,microstructure and chemical composition of single inhalable particles in Shanghai,China

The morphology, microstructure, and chemical composition of a variety of particles emitted from coal-fired power plants, steel plants, and vehicle exhausts, which are possible sources of particulate matter (PM) in the atmosphere, were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and compared with particle samples collected from urban atmosphere to identify the best footprint or the suitable indicator relating the existence of studied particles and their possible emitters by the morphology, microstructure, and chemical composition of the particles. The investigation indicated that the particles from these three sources are different in morphology, microstructure, and chemical composition. Sphere aggregates were generally the most abundant components, with silicon and aluminum as major elements. The urban air particulate contained particles similar to those observed in the power plant, steel plant, and vehicle exhaust samples suggesting that all three sources are contributing to the pollution in the city.     

Study of changes in bacterial and viral abundance in formaldehyde-fixed water samples by epifluorescence microscopy

Accurate measurement of bacterial and viral abundance in coastal marine environments is important to understand the dynamics of microbial communities in these ecosystems. In this study, the effect of formaldehyde preservation on the abundance of bacteria and viruses in water samples from Cochin Backwater was determined by SYBR Green I staining and epifluorescence microscopy. The counts were determined for 45 days in samples fixed with 1?C6% formaldehyde. The results suggest rapid decline in counts of bacteria and viruses in samples preserved in formaldehyde, and the decline increased with increase in the final concentration of formaldehyde in the sample. The initial bacterial and viral counts in the sampling site were 5.2 × 10⁶/ml and 3.9 × 10⁷/ml, respectively. The bacterial count dropped by 5.1%, 53.3%, 55.7%, and 85% after 1, 7, 15, and 45 days, respectively, in sample fixed with 1% formaldehyde. The decline in viral counts was higher, being 32.4%, 47.9%, 68.1%, and 93% after 1, 7, 15, and 45 days, respectively. Storage of fixed samples at ??20°C did not halt the decline in microbial counts, suggesting that, irrespective of storage temperature, formaldehyde-fixed samples lead to underestimation of microbial counts.     

A multivariate examination of ‘artificial mussels’ in conjunction with spot water tests in freshwater ecosystems

Metal pollution in aquatic systems is considered a serious environmental issue globally due to their ability to accumulate in aquatic environments. Wetlands are vulnerable to this pollution as they are known to trap toxins, removing them from the water. Artificial mussel technology, originally developed for marine environments, was applied to this freshwater system and spot water samples were collected. The Nyl River floodplain (Ramsar classified) is one of the largest and most ecologically significant wetlands in South Africa. The aims of this study were to determine metal contamination along the Nyl River system by means of artificial mussels (AM) and water ICP-MS analysis and to determine whether the use of AMs in conjunction with spot water testing could give more insight into the pollution in freshwater wetlands. The concentrations of Al, Cd, Cr, Co, Cu, Fe, Mn, Ni, Pb and Zn were determined at seven sites. It was determined that the levels accumulated by the AMs differed in spatial and temporal trends when compared to spot water samples. It was determined that there were high levels of some metals found in the spot water tests that were not corroborated by the AMs results, which could indicate isolated pollution events. The use of AMs in conjunction with spot water testing was determined to be beneficial in gaining deeper insight into water metal conditions in dynamic freshwater systems.     

Stormwater toxicity in Chollas Creek and San Diego Bay,California

Stormwater discharges from Chollas Creek, a tributary of San Diego Bay, have been shown to be toxic to aquatic life. The primary objective of this study was to provide the linkage between in-channel measurements and potential impairments in the receiving waters of San Diego Bay. This study addressed this objective within the context of four questions: (1) How much area in San Diego Bay is affected by the discharge plume from Chollas Creek during wet-weather conditions?; (2) How much of the wet-weather discharge plume is toxic to marine aquatic life?; (3) How toxic is this area within the wet-weather discharge plume?; and (4) What are the constituent(s) responsible for the observed toxicity in the wet-weather plume? The stormwater plume emanating from Chollas Creek was dynamic, covering areas up to 2.25 km2. Approximately half of the plume was estimated to be toxic to marine life, based upon the results of purple sea urchin (Strongylocentroutus purpuratus) fertilization tests. The area nearest the creek mouth was the most toxic (NOEC = 3 to 12% plume sample), and the toxicity decreased with distance from the creek mouth. The toxicity of plume samples was directly proportional to the magnitude of plume mixing and dilution until, once outside the plume margin, no toxicity was observed. Trace metals, most likely zinc, were responsible for the observed plume toxicity based upon toxicity identification evaluations (TIEs). Zinc was also the constituent identified from in-channel samples of Chollas Creek stormwater using TIEs on the storms sampled in this study, and in storms sampled during the previous storm season.     

Heavy metals in the fishery products of low Lazio and the use of metallothionein as a biomarker of contamination

This study aims to investigate the use of metallothionein as a biomarker and its environmental impact on aquatic systems. According to the species’ characteristics, the interactions of toxic elements with living organisms in marine water can lead to biomagnifications in the trophic chain or bioconcentration of what is in the water. In many aquatic organisms, the presence of metallothionein proteins was studied. The chemical analysis of these bioindicators establishes, therefore, a sensitive method for the measurement of bioavailability which, over the years, allows for the quantification of the current pollution agents in the environment. Two study areas were selected along the Latium coasts. They are differentiated by their economic activities and their kind and level of environmental impact (mainly on marine pollution). These areas were selected in order to differentiate the maximum degree of both economic development and environmental quality. In particular, the presence of pollutants in the sea due to land activities was evaluated to compare the quality of the fishing products obtained from locations subject to various environmental impacts. The heavy metal concentrations were evaluated in water samples taken from different 30 sections of the fishes in order to understand the metabolism and origin of these contaminants. The primary metals studied were: mercury (Hg), zinc (Zn), nickel (Ni), lead (Pb), cadmium (Cd), and copper (Cu). All data produced were analyzed via multivariate analyses in order to provide a final and reliable indicator.     

厦门水库水体颗粒物分布特征及其与环境因子的关系研究

研究了厦门湖边水库、石兜-坂头水库水体颗粒物的分布特征及其与环境因子之间的关系。结果表明:(1)水体颗粒物平均含量以坂头库区最高,石兜库区次之,湖边水库最低,平均含量分别为31.9、27.7和23.1mg/L;在空间分布上,不同水库或库区、不同采样站位间,由于水体颗粒物的来源成因不同,其分布规律呈现出明显的差异。(2)从水体颗粒物与环境因子的关联度分析,湖边水库及石兜-坂头水库两个库区的水体颗粒物与总氮和总磷都有较大关联性。(3)利用Pearson积矩相关系数(两尾)进行检验,湖边水库及石兜-坂头水库两个库区的水体颗粒物均与总氮呈显著或极显著相关,与透明度呈显著负相关,与叶绿素a均呈负相关,与其它因子的相关规律性不明显。(4)水体颗粒物与环境因子的逐步回归分析表明,在不同的水库或库区,对水体颗粒物有显著影响的环境因子各不相同,湖边水库是高锰酸盐指数和总氮,石兜库区是高锰酸盐指数、总氮和总磷,坂头库区是pH、溶解氧和总磷。     

Characterisation of individual aerosol particles on moss surfaces: implications for source apportionment

The size, morphology and chemical composition of 8405 particles on moss surfaces (Hylocomium splendens) was investigated by scanning electron microscopy and energy-dispersive X-ray microanalysis. Two moss samples from three locations in Southern Norway (Alg?rd, Birkeland, Neslandsvatn) and two sampling years (1977 and 2005) each were selected leading to a total of 12 samples investigated. At all three locations, particle deposition decreased substantially with time. The major particle groups encountered include silicates, iron-rich silicates, metal oxides/hydroxides, iron oxides/hydroxides, carbonates, carbon-rich particles, silicate fly ashes, iron-rich silicate fly ashes, and iron oxide fly ashes. Between 1977 and 2005, the relative number abundance of the three fly ash groups decreased substantially from approximately 30-60% to 10-18% for the small particles (equivalent projected area diameter <1 microm), and from 10-35% to 2-9% for large particles with diameters ≥1 microm. This decrease of fly ash particles with time was overlooked in previous papers on atmospheric input of pollutants into ecosystems in Southern Norway. In general, the presence of fly ash particles is ignored in most source apportionment studies based on bulk chemical analysis. Consequently, the geogenic component (crustal component) derived from principal component analysis is overestimated systematically, as it has a similar chemical composition as the fly ash particles. The high abundance of fly ashes demonstrates the need to complement source apportionment based on bulk chemistry by scanning electron microscopy in order to avoid misclassification of this important anthropogenic aerosol component.     

Comparison of wood-dust aerosol size-distributions collected by air samplers

A method has been described previously for determining particle size distributions in the inhalable size range collected by personal samplers for wood dust. In this method, the particles collected by a sampler are removed, suspended, and re-deposited on a mixed cellulose-ester filter, and examined by optical microscopy to determine particle aerodynamic diameters. This method is particularly appropriate to wood-dust particles which are generally large and close to rectangular prisms in shape. The method was used to investigate the differences in total mass found previously in studies of side-by-side sample collection with different sampler types. Over 200 wood-dust samples were collected in three different wood-products industries, using the traditional 37 mm closed-face polystyrene/acrylonitrile cassette (CFC), the Institute of Occupational Medicine (IOM) inhalable sampler, and the Button sampler developed by the University of Cincinnati. Total mass concentration results from the samplers were found to be in approximately the same ratio as those from traditional long-term gravimetric samples, but about an order of magnitude higher. Investigation of the size distributions revealed several differences between the samplers. The wood dust particulate mass appears to be concentrated in the range 10-70 aerodynamic equivalent diameter (AED), but with a substantial mass contribution from particles larger than 100 microm AED in a significant number of samples. These ultra-large particles were found in 65% of the IOM samples, 42% of the CFC samples and 32% of the Button samples. Where present, particles of this size range dominated the total mass collected, contributing an average 53% (range 10-95%). However, significant differences were still found after removal of the ultra-large particles. In general, the IOM and CFC samplers appeared to operate in accordance with previous laboratory studies, such that they both collected similar quantities of particles at the smaller diameters, up to about 30-40 [micro sign]m AED, after which the CFC collection efficiency was reduced dramatically compared to the IOM. The Button sampler collected significantly less than the IOM at particle sizes between 10.1 and 50 microm AED. The collection efficiency of the Button sampler was significantly different from that of the CFC for particle sizes between 10.1 and 40 microm AED, and the total mass concentration given by the Button sampler was significantly less than that given by the CFC, even in the absence of ultra-large particles. The results are consistent with some relevant laboratory studies.     

Multiparametric approach for an exemplary study of laser printer emissions

The aim of this work was the study, by a multiparametric approach, of emissions from a laser printer in an experimental box-chamber, with particular attention to nanoparticles release. The experimental design included number concentration measurements by Fast Mobility Particle Sizer (FMPS) and chemical characterizations (elements) of size segregated samples collected by Nanomoudi cascade impactor. Volatile Organic Compounds (VOCs) were also sampled by charcoal sorbent tubes by personal sampling pumps. Monitoring of ozone, total volatile organic compounds concentrations and of temperature and humidity values inside the experimental box during the printing processes were also performed by automatic analyzers. The performed monitoring allowed to evidence different ways for particles emissions by laser printers, in particular showing that nanoparticles, characterised by high concentrations of Ba, Zn, B, K, Sr and Na, are set free at the beginning of the printing process. This emission seems to be directly ascribable to the use of toner powder, as all these elements are present in it. The emission of larger particles (ca. 100-320 nm) was observed in subsequent phases of the print process, probably due to the condensation of vapours released during the progressive heating of the fuser roller. This contribution was proved by both the FMPS measurements and the cascade impactor results. Also, a low emission of particles in higher size ranges was evidenced, mainly due to paper related particles. A very high concentration of VOCs was detected inside the chamber and the chemical speciation shows that the major contribution is associated to toner components, even if some species are released from other printer components. Although the formation of secondary species by reaction of VOCs with ozone cannot be excluded, these species were present inside the chamber at concentrations lower than the detection limit.     

Acidification in Arabian Gulf--insights from pH and temperature measurements

The detrimental effects of increasing atmospheric levels of carbon dioxide (CO(2)) and other greenhouse gases since the industrial revolution has led to a concerted international effort to control their release and abate the environmental and human health impacts. CO(2) is removed from the atmosphere by photosynthesis of plants in the terrestrial environment and by aquatic sequestration. In the Middle East and other arid countries, terrestrial removal is minimal. The most likely removal pathway for CO(2) in arid regions around the world is by aquatic sequestration. In the Middle East the major sink is the Arabian Gulf which leads to acidification of the marine environment. Biweekly pH concentration measurements in surface waters of the northern Arabian Gulf over a four year period in this study suggest that the Arabian Gulf waters are becoming increasingly acidic with time. Supporting evidence for increased CO(2) sequestration comes from increased marine primary productivity over the past decade. Biological effects, such as coral bleaching, observed during this period suggest that urgent action is required to reverse the trend and protect marine life. The data highlight the fact that this semi-enclosed sea is undergoing a rapid degradation which may affect the oceanic chemistry and biogeochemical cycle much earlier than predicted for most oceanic waters.     

Classification of particles from the farm environment by automated sizing, counting and chemical characterisation with scanning electron microscopy-energy dispersive spectroscopy

About 60,000 particles in 288 aerosol samples collected during farm work have been characterised with automated particle analysis using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Based on EDS-analysis of materials with known composition (potato flour, alpha-quartz, K-feldspar and beta-wollastonite), criteria were developed for classification of particles as: (1) organic, (2) silicon-rich (silica), and (3) other inorganic particles. The reproducibility of the relative mass proportions in dust samples collected during farm work was 0.078 when approximately 200 particles were characterised per sample. Field samples from the farm environment showed clear differences in composition. Generally, inorganic particles dominated the particle mass. The proportion of the organic particle mass was highest for tending of swine and poultry, 55 and 38% respectively. Silica particles amounted to 10 to 20% of the total mass during handling crops, e.g. grain, straw, hay, potatoes, and onions. It seems likely that the results can be used in etiologic studies, but further validation would be needed for quantitative purposes.     

The distribution of triclosan and methyl-triclosan in marine sediments of Barker Inlet, South Australia

In this work, we investigated the transport and burial of triclosan and its methylated derivative, in surface sediments near the mouth of Barker Inlet in South Australia. The most likely source of this commonly used bactericide to the area is a wastewater outfall discharging at the confluence of the inlet with marine waters. Triclosan was detected in all samples, at concentrations (5-27 μg kg(-1)) comparable to values found in other surface sediments under the influence of marine wastewater outfalls. Its dispersal was closely associated with fine and organic-rich fractions of the sediments. Methyl-triclosan was detected in approximately half of the samples at concentrations <11 μg kg(-1). The occurrence of this compound was linked to both wastewater discharges and biological methylation of the parent compound. Wastewater-borne methyl-triclosan had a smaller spatial footprint than triclosan and was mostly deposited in close proximity to the outfall. In situ methylation of triclosan likely occurs at deeper depositional sites, whereas the absence of methyl-triclosan from shallower sediments was potentially explained by photodegradation of the parent compound. Based on partition equilibrium, a concentration of triclosan in the order of 1 μg L(-1) was estimated in sediment porewaters, a value lower than the threshold reported for harmful effects to occur in the couple of species of marine phytoplankton investigated to date. Methyl-triclosan presents a greater potential for bioaccumulation than triclosan, but the implications of its occurrence to aquatic ecosystem health are difficult to predict given the lack of ecotoxicological data in the current literature.     

Occurrence and removal of titanium at full scale wastewater treatment plants: implications for TiO2 nanomaterials

Titanium dioxide nanoparticles increasingly will be used in commercial products and have a high likelihood of entering municipal sewage that flows to centralized wastewater treatment plants (WWTPs). Treated water (effluent) from WWTPs flows into rivers and lakes where nanoparticles may pose an ecological risk. To provide exposure data for risk assessment, titanium concentrations in raw sewage and treated effluent were determined for 10 representative WWTPs that use a range of unit processes. Raw sewage titanium concentrations ranged from 181 to 1233 μg L(-1) (median of 26 samples was 321 μg L(-1)). The WWTPs removed more than 96% of the influent titanium, and all WWTPs had effluent titanium concentrations of less than 25 μg L(-1). To characterize the morphology and presence of titanium oxide nanoparticles in the effluent, colloidal materials were isolated via rota-evaporation, dialysis and lyophilization. High resolution transmission electron microscopy and energy dispersive X-ray analysis indicated the presence of spherical titanium oxide nanoparticles (crystalline and amorphous) on the order of 4 to 30 nm in diameter in WWTP effluents. This research provides clear evidence that some nanoscale particles will pass through WWTPs and enter aquatic systems and offers a methodological framework for collecting and analyzing titanium-based nanomaterials in complex wastewater matrices.     

Detection of benzotriazole UV stabilizers in the blubber of marine mammals by gas chromatography-high resolution mass spectrometry (GC-HRMS)

Benzotriazole UV stabilizers (BUVSs), such as UV-328 and UV-327, were identified in the blubbers of finless porpoises (Neophocaena phocaenoides) collected from the Ariake Sea, western Japan, by gas chromatography-high resolution mass spectrometry (GC-HRMS). The mean concentrations and standard deviations of UV-328 and UV-327 in five blubber samples were 38 ± 28 ng g(-1) (lipid wt) and 19 ± 19 ng g(-1), respectively. The bioconcentration factor (BCF) of UV-327 between water and finless porpoises was estimated to be 33?300, which is approximately one order of magnitude higher than that found for small fish inhabiting the same regions. The BCF of UV-327 in finless porpoises was similar to that of persistent organochlorine pesticide, hexachlorocyclohexane (HCH: 37?000) in marine mammals from the western North Pacific Ocean. These results suggest that BUVSs appear to be persistent and bioaccumulative in the aquatic food chain. Further investigations on temporal trends, and regional and global monitoring of BUVSs are needed to understand their environmental profiles and potential risks to wildlife and human.     

1,1,1-Trichloroethane Marine Risk Assessment with Special Reference to the Osparcom Region: North Sea

This risk assessment on 1,1,1-trichloroethane was carried out specifically for the marine environment, accordingly to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). 1,1,1-trichloroethane is being phased out of most uses because of its ozone depletion potential (ODP) under the Montreal Protocol. Production for emissive uses has already been phased out end 1995 in Europe and 1996 in the United States, Japan and other industrial countries. The risk assessment study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programmes in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the Predicted Environmental Concentration (PEC) and the Predicted No-Effect Concentration (PNEC) for the marine aquatic environment. In total 14 studies for fish, 7 studies for invertebrates and 9 studies for algae have been evaluated. Both acute and chronic studies have been taken into account and the appropriate assessment factors have been used to calculate a PNEC value of 21 microg/l based on long term exposure. The PEC was derived from monitoring data. The PEC was set at 0.206 microg/l (worst case) and 0.024 microg/l (typical case) for coastal waters and estuaries and 0.6 microg/l (worst case) and <0.1 microg/l (typical case) for river waters. The calculated PEC/PNEC ratios, which do not take into account any dilution factor within the sea, correspond to a safety margin of 35 to 1000 between the aquatic effect and the exposure concentration. 1,1,1-trichloroethane is not a 'toxic, persistent and liable to bioaccumulate' substance according to the criteria as mentioned by the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). It can be concluded that the present use of 1,1,1-trichloroethane does not present a risk to the marine aquatic environment.     

2008年北京市PM_(10)的粒度分布分形维数变化特征

2007年11月-2008年10月间在北京市市中心和西北城区采集了不同季节的PM10样品,并借助扫描电子显微镜和图像分析软件对其进行粒度分布分形维数分析。结果表明,颗粒物中细颗粒物越多,粒度越细,则颗粒物粒度分布分形维数值越大。2008年西北城区的PM10的粒径分布分形维数较大,市中心的较小。市中心的粒度分布分形维数在1.95～2.59之间,各个季节的分形维数呈现冬季春季夏季秋季,西北城区的粒度分布分形维数在2.58～2.72,各个季节的分形维数呈现秋季夏季冬季春季,说明在市中区冬季PM10粒度较细,而在西北城区秋季的颗粒物偏细。与2005年同季相比,2008年的总体颗粒物和烟尘集合体的粒径分布分形维数较大,矿物颗粒的粒度分布分形维数较小,并且总分布的季节变化一致。2008奥运期间的PM10粒度分布分形维数在2.28～3.39之间变化,标志着颗粒物总体变细的趋势。     

High throughput analysis of solid-bound endocrine disruptors by LDTD-APCI-MS/MS

The development of a high-throughput method for the analysis of 14 endocrine-disrupting substances in environmental solid matrices has been investigated. Selected compounds were: hormones (estrogens and progestogens), parabens and triclocarban. The ultrafast method (15 s per sample) is based on the laser diode thermal desorption-atmospheric pressure chemical ionization (LDTD-APCI) coupled to tandem mass spectrometry (MS/MS). This novel approach was tested and validated in three different solid matrices (municipal sludge cakes, aquatic sediments and agricultural soils) and its performance was evaluated by estimation of extraction recovery, linearity, precision, and detection limits. In contrast to other methods based on LC-MS/MS, a cleanup step is not necessary or minimal for the municipal sludge cake matrix. Extraction recoveries ranged from 80 to 109% for all compounds in all matrix types except for estriol which was 60-75%. The intra- and inter-day precisions, as indicated by % RSD, were ≤ 14% and ≤ 16%, respectively. The method detection limits ranged from 0.7 to 4.0 ng g?1 in sediments and soil matrices and 2.8 to 16.8 ng g?1 for municipal sludge cake samples. The results for real environmental samples collected in different areas of Quebec (Canada) are illustrated.     

Polybrominated diphenyl ethers (PBDEs) in the riverine and marine sediments of the Laizhou Bay area, North China

62 riverine and marine sediments were collected from the Laizhou Bay area, where the largest manufacturing base of brominated flame retardants (BFRs) in Asia is located. Eight polybrominated diphenyl ethers (PBDEs) were analyzed to investigate the impact of rapidly-developed bromine industries on the regional aquatic system. PBDE concentrations varied largely in riverine sediments. Σ(7)PBDEs (including BDE 28, 47, 99, 100, 153, 154 and 183) and BDE 209 ranged from 0.01 to 53 ng g(-1) dw and from 0.74 to 285 ng g(-1) dw with a mean value of 4.5 ng g(-1) dw and 54 ng g(-1) dw, respectively, indicating a strong influence of direct pollution discharges from local factories. In marine sediments, Σ(7)PBDEs and BDE 209 ranged from not detected (nd) to 0.66 ng g(-1) dw and from 0.66 to 12 ng g(-1) dw with a mean value of 0.32 ng g(-1) dw and 5.1 ng g(-1) dw, respectively. PBDE concentrations were mostly <10 ng g(-1) dw for Σ(7)PBDEs and <50 ng g(-1) dw for BDE 209, which are at a relatively low level for monitored riverine and coastal sediments around the world. Even at the most contaminated sites in Laizhou Bay area, PBDE concentrations were not among the highest concentrations reported in the literature. Congener compositions were dominated by BDE 209 (57.2-99.9% of the sum of BDE congeners), with minor contributions from penta- and octa-BDE products. Tri- to octa-BDE congeners were well correlated among each other (r > 0.75) and thus sources from similar mixing of penta- and octa-BDE products were suggested in this area. Compared with riverine sediments, a much better correlation between PBDE concentrations with TOC was observed in marine environment. The congener pattern changed and their correlation coefficients among each other were remarkably reduced. Contributions of BDE 28, 47 and 99 to Σ(7)PBDEs were generally the same in almost all the marine sites, while it was distinctively higher for BDE 153. These are probably attributable to several reasons, such as contributions by atmospheric deposition and/or redistribution between particles of various sizes during and/or after fluvial transportation combined with the difference of physiochemical properties of BDE congeners.