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1.
Atmospheric wet deposition of PAHs to the sea-surface microlayer   总被引：1，自引：1，他引：0  
Sea-surface microlayer (SML) and subsurface seawater samples (SSW) collected from Singapore's coastal environment were analyzed for 14 polycyclic aromatic hydrocarbons (PAHs) in the dissolved (DP) and suspended particulate phase (SPM). Samples were collected prior to and after rainfall events to ascertain the contribution of wet atmospheric deposition of PAH enrichment to the SML. The concentration ranges of summation operatorPAHs in the SML before rain and after wet deposition were 2.6-46.2 ngL(-1) and 4.3-278.0 ngL(-1), respectively, for the DP and 3.8-31.4 ngL(-1) and 12.8-1280 ngL(-1), respectively, for the SPM. Load factors (i.e. concentration after wet deposition relative to before wet deposition) of the atmospheric wet deposition for DP and SPM ranged from 1.4 to 42.9 and 1.2 to 337, respectively. This study provides the first data on PAH concentration, enrichment (i.e. concentration of PAHs in SML relative to subsurface water) and load factors in the SML before and after wet deposition to the ocean surface.  相似文献   

2.
Polycyclic aromatic hydrocarbons (PAHs) were measured in the coastal sea surface microlayer (SML), the sub-surface waters (SSW) and the overlying atmosphere in order to investigate the influence of the SML on contaminant enrichment and air-sea exchange. Samples were collected at two contrasting locations of the NW Mediterranean, one urban influenced (off Barcelona, Spain) and another comparatively clean (off Banyuls-sur-Mer, France). Statistical data analysis confirmed the accumulation of PAHs in the SML with respect to the SSW (20.3+/-9.1 vs. 13.1+/-10.0 ng L(-1) in the dissolved phase; 709+/-207 vs. 158+/-111 ng g(-1) in the particulate phase). This accumulation was higher at the contaminated location (Barcelona station) compared with the more pristine one, with PAH enrichments 1.5 and 4.5 times higher for the dissolved and particulate phases, respectively, indicating that the enrichment of PAHs in the SML is dominated by particle transport processes.  相似文献   

3.
Aliphatic (AHs) and polycyclic aromatic hydrocarbons (PAHs) were analyzed in dissolved and particulate material from surface microlayer (SML) and subsurface water (SSW) sampled at nearshore observation stations, sewage effluents and harbour sites from Marseilles coastal area (Northwestern Mediterranean) in 2009 and 2010. Dissolved and particulate AH concentrations ranged 0.05–0.41 and 0.04–4.3 μg l−1 in the SSW, peaking up to 38 and 1366 μg l−1 in the SML, respectively. Dissolved and particulate PAHs ranged 1.9–98 and 1.9–21 ng l−1 in the SSW, amounting up 217 and 1597 ng l−1 in the SML, respectively. In harbours, hydrocarbons were concentrated in the SML, with enrichment factors reaching 1138 for particulate AHs. Besides episodic dominance of biogenic and pyrogenic inputs, a moderate anthropisation from petrogenic sources dominated suggesting the impact of shipping traffic and surface runoffs on this urbanised area. Rainfalls increased hydrocarbon concentrations by a factor 1.9–11.5 in the dissolved phase.  相似文献   

4.
The polycyclic aromatic hydrocarbons (PAHs) pollution in the Sarno River and its environmental impact on the Gulf of Naples (Tyrrhenian Sea, Central Mediterranean Sea) were estimated. The 16 PAHs identified by the USEPA as priority pollutants and perylene were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediments. Total PAHs concentrations ranged from 23.1 to 2670.4 ng L(-1) in water (sum of DP and SPM) and from 5.3 to 678.6 ng g(-1) in sediment samples. Source analysis revealed that PAHs mainly came from combustion process. Contaminant discharges of PAHs into the sea were calculated in about 8530 gd(-1) showing that this river should account as one of the main contribution sources of PAHs to the Tyrrhenian Sea.  相似文献   

5.
Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) are two classes of micropollutants intensively monitored and regulated due to their toxicity, persistency and wide diffusion. Their concentrations have been investigated in sea-microlayer (SML) and sub-surface water (SSW) samples collected at two sites of the Venice Lagoon, a fragile ecosystem highly influenced by industrial and anthropogenic emissions. The total sigmaPCB concentration varies from 0.45 ng/l to 2.1 ng/l in SSW while a clear enrichment is observed in the SML, where it ranges from 1.2 ng/l to 10.5 ng/l. The total sigmaPAH concentration shows marked differences between the two stations and varies from 12.4 ng/l to 266.8 ng/l in SSW; in SML it is more uniform and ranges from 19.6 ng/l to 178.9 ng/l. The enrichment factors are not larger than 1 for both pollutants in the 'dissolved' phase, while they are most significant for the 'particulate' phase (sigmaPCB: 5-9; sigmaPAH: 4-14).  相似文献   

6.
Determinations of dissolved reactive and total dissolved mercury, particulate and sedimentary mercury, dissolved organic carbon (DOC), particulate organic carbon (POC) and suspended particulate matter (SPM) have been made in the estuary of river Douro, in northern Portugal. The estuary was stratified by salinity along most of its length, it had low concentrations of SPM, typically <20 mg dm(-3), and concentrations of DOC in the range <1.0-1.8 mg dm(-3). The surface waters had a maximum dissolved concentration of reactive mercury of about 10 ng dm(-3), whereas for the more saline bottom waters it was about 65 ng dm(-3). The surface waters had maximum concentrations of total suspended particulate mercury of approximately 7 microg g(-1) and the bottom waters were always <1 microg g(-1). Concentrations of mercury in sediments was low and in the range from 0.06 to 0.18 microg g(-1). The transport of mercury in surface waters was mainly associated with organic-rich particulate matter, while in bottom waters the dissolved phase transport of mercury is more important. Lower particulate organic matter, formation of chlorocomplexes in more saline waters and eventually the presence of colloids appear to explain the difference of mercury partitioning in Douro estuarine waters.  相似文献   

7.
《Marine pollution bulletin》2014,78(1-2):110-117
Sea microlayer (SML) and subsurface water (SSW) samples were collected around Xiamen Island to study the enrichment and partitioning of polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations ranged from 93.43 to 411.05 ng L−1 in the SML and 49.29–279.42 ng L−1 in the SSW. Compared with the results of previous studies before pollution control measurements, PAHs levels decreased significantly. The enrichment factors (EFs) of dissolved and particulate PAHs varied from 0.68 to 2.71 and 0.43–3.56. EFs showed the consistent enrichment trends with sites and exhibited different enrichment characteristics between 2 and 3 ring PAHs and 4 ring PAHs. Furthermore, the much higher concentrations of BaP (strong carcinogenicity) were accompanied by higher EFs in the SML samples from the Western Xiamen Harbour, which together indicated the risk of impacts to the fish eggs that usually float on the SML water after exposure to oil spills and combustion, contributed directly by the port and shipping activities.  相似文献   

8.
Historical trends of organic pollutants in sediment cores from Hong Kong   总被引：1，自引：0，他引：1  
Recent studies have indicated the occurrence of a wide range of trace organic contaminants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Hong Kong environment. These contaminants are potentially harmful to ecological systems, particularly in coastal areas. In this study, two sediment cores (4m) were collected from southern waters of Hong Kong in 2004 to study the historical trends, distribution patterns, and potential sources of trace organic contaminants. DDTs (p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD and p,p'-DDE), hexachlorohexanes (HCHs) (alpha and gamma), hexachlorobenzene (HCB), and PCBs were detected in the samples, whereas other target compounds were all below detection limits. Many OCPs have not been produced or used for many years due to toxicological or environmental concerns and PCB use is prohibited in Hong Kong. However, some compounds were still detectable in recent years, and were found to be widely distributed in the environment, likely because of pollutant inputs from the highly industrialized Pearl River Delta region. These results provide important information on current and historical contamination in Hong Kong, and help to reconstruct the pollution history of these trace organic pollutants in Hong Kong coastal waters.  相似文献   

9.
The impact of seasonal fluctuations in forcing factors such as atmospheric concentration, temperature, and biological productivity on the concentration of polychlorinated biphenyls (PCBs) in the surface water of the southern part of the Baltic Sea was investigated. Water samples were collected on eight cruises over 2 years. A clear seasonal variability in dissolved PCB concentrations was observed with higher levels in summer than in winter and spring. This was attributed to changes in atmospheric concentrations and water temperature, based on measurements showing the PCB levels in the atmosphere and surface water to be close to a partitioning equilibrium. Concentrations in the suspended particulate material (SPM) fraction were also variable, and when the quotient of the organic carbon normalised concentration in SPM and the dissolved concentration was calculated (i.e., the bioaccumulation factor (BAF)), a seasonal pattern was observed which was consistent with kinetic limitations on partitioning into particles caused by plankton growth. However, seasonal variability in the partitioning properties of the SPM may also contribute to this variability.  相似文献   

10.
Water from the Susquehanna River was collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCB) congeners to estimate seasonal and annual riverine loads to the Chesapeake Bay. Temporal variations in the chemical loads resulted from the large changes in the water flow rates and in the particle-associated contaminant concentrations. Concentrations of PCBs and PAHs in river particles (ng/g) were twice as great as those in the northern Chesapeake Bay, indicating that the Susquehanna River is an important source of these contaminants to the bay. The river carries a majority of its hydrophobic organic contaminants (HOCs) in the particulate phase. During periods of high flow, large amounts of suspended particles in the river result in elevated HOC levels and increased loadings of these contaminants to the bay. From 1997 to 1998, 60% of the total annual HOC loading occurred in the early spring coincident with high river flows. The total PCB and PAH annual loadings from the Susquehanna River to the Chesapeake Bay were 76 and 3160 kg/year, respectively and 75% of the loaded organic contaminants were in the particulate phase. Principal component analysis of PAH and PCB congener patterns in the particles reveals that the river suspended particles were dominated by autochthonous production in the summer and by resuspended sediment and watershed erosion during the winter and early spring.  相似文献   

11.
Distribution and Fate of Organochlorine Pollutants in the Pearl River Estuary   总被引：42，自引：0，他引：42  
Samples of surface sediment and suspended particulate matter (SPM) were collected from the Pearl River estuary, China, and the distribution and concentration of hexachlorocyclohexanes (HCHs), DDTs and polychlorinated biphenyls (PCBs) were extensively studied. The concentration ranges of HCHs, DDTs and PCBs in the sediments were 0.28–1.23 ng g−1, 1.36–8.99 ng g−1 and 0.18–1.82 ng g−1, respectively. The concentrations of HCHs, DDTs and PCBs in the SPM varied both with the sampling locations and the season of collection. Higher concentrations were recorded in the SPM as compared with sediments. The distribution pattern of such organochlorine compounds (OCs), in the Pearl River estuary, showed that sources were some major river mouths and input from Shenzhen Bay. The concentrations of OCs were, however, low as compared with other estuaries and seas. The environmental fate of the OCs during estuarine mixing was determined, in part, by physicochemical and biochemical properties. The absorption and sedimentation of SPM were also considered important factors. Marine sediments may, therefore, be regarded as an important reservoir of hydrophobic and persistent OCs.  相似文献   

12.
Sea-surface microlayer (SML) and seawater samples collected from Singapore's coastal marine environment were analyzed for selected chlorinated pesticides and polychlorinated biphenyls (PCBs). The SML is a potential site of enrichment of persistent organic pollutants (POPs) compared to the underlying water column. The concentration ranges of SigmaHCH, SigmaDDT and SigmaPCB in subsurface (1 m depth) seawater were 0.4-27.2 ng/l (mean 4.0 ng/l), 0.01-0.6 ng/l (mean 0.1 ng/l) and 0.05-1.8 ng/l (mean 0.5 ng/l) respectively. In the SML, the concentration ranges of SigmaHCH, SigmaDDT and SigmaPCB were 0.6-64.6 ng/l (mean 9.9 ng/l), 0.01-0.7 ng/l (mean 0.2 ng/l) and 0.07-12.4 ng/l (mean 1.3 ng/l) respectively. High spatial and temporal distribution was observed for all POPs measured. However, overall levels measured in the SML were lower than levels reported in the literature for SML samples from temperate coastal regions-possibly due to loss of semi-volatile compounds in the tropical climate of Singapore. Atmospheric wet deposition during the monsoon season may be an important source of POPs to the SML. This study provides the first scientific data on POP concentrations and enrichment factors in the SML for Southeast Asia.  相似文献   

13.
The composition and amount of colloidal and suspended participate matter transported during a small flood event in Magela Creek in tropical northern Australia was investigated. The flood studied constituted approximately 3 % of the total annual flow, most (90%) of which occurred between mid-January and mid-February of the study year. Three fractions were separated from water samples using a sequential method involving a continuous flow centrifuge to separate suspended particulate matter (SPM; nominally > 1 μm) followed by hollow fibre filtration, first using a 0.1 μm filter to separate course colloidal matter (CCM; nominal size 1–0.1 μm) and then a 0–015 μm filter to separate fine colloidal matter (FCM; nominal size 0.1–0.015 μm). The SPM was predominantly inorganic (organic matter 21 %), whereas the colloidal fractions were dominantly organic matter (CCM 60%; FCM 83%). Analysis of individual particles using electron microprobe and automated image analysis indicated that the mineral fractions in both the SPM and CCM were dominated by iron-enriched aluminosilicates (including kaolinite) (72–82%) and quartz (9–10%), indicative of a highly weathered and extensively laterized catchment. Surprisingly there was very little difference in the composition of the SPM or CCM fractions during the flood event studied, which may indicate either that sediment availability was restricted following the major run-off events in January and February, or that all the sediment sources within the catchment are geochemically similar. Approximately the same amounts of particulate (20 tonne), colloidal (21 tonne) and dissolved material (17 tonne) were transported during the 25 hour period of the main flood peak; over 90% of the colloidal matter was 0.1–1.0 μm in size. These data suggest that previous estimates of the amounts of particulate (and colloidal) matter transported by Magela Creek, which were based on suspended solids measurements, may have underestimated the particulate matter load by as much as 50%. It is possible that the relatively high proportion of colloidal matter is unique to Magela Creek because coagulation and aggregation of colloidal matter to particulate matter is slow due to the very low concentations of calcium and magnesium in these waters. However, if the result is more widespread, there are important implications for the global estimates of fluvially transported particulate and dissolved materials as many of the previous studies may have underestimated the particulate load and overestimated the dissolved load.  相似文献   

14.
Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in surface and core sediment samples collected from Manzala Lake, the largest of the Egyptian coastal lakes. Total concentrations of OCPs and ∑7 PCBs (ICES) in sediments ranged from 0.63 to 31.31 ng/g and 0.26 to 31.27 ng/g, respectively. Geographical distribution indicates that levels of contaminants were significantly higher in areas which are mainly influenced by municipal discharge, indicating significant sources of these compounds in urbanised areas. The composition of DDT and its metabolites suggest old input of DDT. The levels of contaminants in Manzala Lake were similar or lower than those observed in comparable areas worldwide. The profiles of ∑OCPs and ∑PCBs in a core from a site heavily impacted by sewage discharge have highest concentrations in the surface core section indicating recent inputs. Assessment of ecotoxicological risk indicated that sediments in two sites were likely to pose potential biological adverse impact.  相似文献   

15.
Ocean Dynamics - Suspended particulate matters (SPM) in coastal waters were investigated with an approach combining suspended particulate matter concentrations (SPMCs) measured by an optical...  相似文献   

16.
A total of 1008 samples were collected from the eight major riverine runoff outlets in the Pearl River Delta (PRD) during 2005-2006 to estimate the fluxes of total organic carbon (TOC) to the coastal ocean off South China. The average dissolved organic carbon (DOC) concentration was 1.67 mg/L with a range of 1.38-2.13 mg/L. Concentrations of particulate organic carbon (POC) ranged from 2.66-4.12% of total suspended particulate matter (SPM). The fluxes of TOC and SPM from the PRD via the eight outlets were 9.2 x 10(5) and 2.5 x 10(7)tons/yr, respectively. Temporal variations in POC and DOC were observed at all outlets due to the large variability in runoff levels because of the seasonality of rainfall, and the riverine discharge amount was an important factor controlling TOC flux. The net contribution of organic carbon from the PRD to the coastal ocean represented approximately 0.1-0.2% of total organic carbon transported by rivers worldwide.  相似文献   

17.
The sea surface microlayer (SML) may play an important role on the transport and fate of persistent organic pollutants in the marine environment. In order to evaluate the appropriateness of a number of sampling devices for the analysis of 14 parent polycyclic aromatic hydrocarbons (3-5 aromatic rings), marine SML waters were sampled using a glass plate, a rotating drum/roller, a metal screen and a surface slick sampler. The underlying waters were also sampled for the determination of the corresponding enrichment factors (EF = [C](microlayer)/[C](underlying water)). The EFs were phase dependent, ranging from 1 to 3 for the dissolved phase and between 4 and 7 for the particulate phase. In order to better assess the performance of the different sampling methods, in terms of phase partitioning, the truly dissolved and colloidal phases were also estimated. Generally, no significant differences were found for the enrichment factors provided by the different methods, due to the observed large variability in concentrations that can be attributed to small-scale coastal processes. However, the metal screen is recommended as the most efficient sampling method for the study of PAHs taking into account the amount of water collected versus time.  相似文献   

18.
Seawater samples (including surface water and bottom water) were collected from the Western Taiwan Strait (WTS) during June 24-25, 2009; polycyclic aromatic hydrocarbons (PAHs) in dissolved phase and particulate phase were analyzed, respectively. The results showed that the total concentrations of PAHs in the dissolved phase and particulate phase were ranged from 12.3 to 58.0 ng L(-1), and 10.3-45.5 ng L(-1), which showed a low-middle contamination level in the China Seas. The spatial variability of PAHs may be related to the complicated currents of WTS, especially the Min-Zhe coastal current. PAHs diagnostic ratios suggested that PAHs mainly originated from the inputs of pyrolytic (combustion) sources, which might be contributed to land-based atmospheric deposition. The particle-water partition coefficients of individual PAH showed that partitions were not correlated with suspended particulate matter content, dissolved organic carbon or salinity, similar to the Yangtze coastal area.  相似文献   

19.
234Th:238U disequilibria have been used extensively as tracers of particle dynamics in marine environments. 234Th (t1/2=24.1 days) can be used as “proxy” for particle reactive pollutants, due to their similar rapid rate of scavenging onto particles and subsequent removal from the water column, to the sediments. Radioactive disequilibrium can be exploited to determine the rates and time-scales of processes occurring over days to months; in this instance the residence times of dissolved and particulate species with the benthic nepheloid layer (BNL).Three sampling cruises were undertaken in Thermaikos Gulf (NW Aegean Sea) during contrasting periods, to examine the impact of natural and anthropogenic activity on sediment resuspension. September and October 2001 represented background and trawling periods, respectively; January 2002 represented a mixed period, of trawling and storms.Dissolved 234Th is scavenged actively at the BNL, in the presence of suspended particulate material (SPM), with a mean residence time of 16 days. There is a weak inverse correlation between dissolved 234Th residence time and SPM concentration in the BNL, with the shortest residence times occurring during October 2001. No relationship was observed between particulate 234Th activities and SPM concentrations, indicating that particles are rapidly removed from the system, either by sinking or advection. The mean particulate 234Th residence time is 5 days.  相似文献   

20.
Persistent organic pollutants in remote freshwater ecosystems   总被引：3，自引：0，他引：3  
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