Comparative sediment quality assessment in different littoral ecosystems from Spain (Gulf of Cadiz) and Brazil (Santos and São Vicente estuarine system)

The goal of this work was to establish comparisons among environmental degradation in different areas from Southern Spain (Gulf of Cádiz) and Brazil (Santos and S?o Vicente estuary), by using principal component analyses (PCA) to integrate sediment toxicity (amphipods mortality) and chemical-physical data (Zn, Cd, Pb, Cu, Ni, Co, V, PCBs, PAHs concentrations, OC and fines contents). The results of PCA extraction of Spanish data showed that Bay of Cádiz, CA-1 did not present contamination or degradation; CA-2 exhibited contamination by PCBs, however it was not related to the amphipods mortality. Ría of Huelva was the most impacted site, showing contamination caused principally by hydrocarbons, in HV-1 and HV-2, but heavy metals were also important contaminants at HV-1, HV-2 and HV-3. Algeciras Bay was considered as not degraded in GR-3 and -4, but in GR-3' high contamination by PAHs was found. In the Brazilian area, the most degraded sediments were found in the stations situated at the inner parts of the estuary (SSV-2, SSV-3, and SSV-4), followed by SSV-6, which is close to the Submarine Sewage Outfall of Santos - SSOS. Sediments from SSV-1 and SSV-5 did not present chemical contamination, organic contamination or significant amphipod mortality. The results of this investigation showed that both countries present environmental degradation related to PAHs: in Spain, at Ría of Huelva and Gudarranque river's estuary areas; and in Brasil, in the internal portion of the Santos and S?o Vicente estuary. The same situation is found for heavy metals, since all of the identified metals are related to toxicity in the studied areas, with few exceptions (V for both Brazil and Spain, and Cd and Co for Brazilian areas). The contamination by PCBs is more serious for Santos and S?o Vicente estuary than for the investigated areas in Gulf of Cádiz, where such compound did not relate to the toxicity.     

Derivation of predicted no effect concentrations (PNEC) for marine environmental risk assessment: application of different approaches to the model contaminant Linear Alkylbenzene Sulphonates (LAS) in a site-specific environment

Four sediment-dwelling marine organisms were exposed to sediments spiked with increasing concentrations of Linear Alkylbenzene Sulphonate (LAS). The selected endpoint mortality was reported daily and acute LC(50) (96 h), as well as final LC(10) values were calculated for the derivation of environmentally safe predicted no effect concentrations (PNEC) for the sediment compartment. PNECs were estimated by both application of assessment factors (AF) and the equilibrium partitioning method (EPM) as proposed by the EU TGD. Finally, environmental risk assessment in a site-specific environment, the Sancti Petri Channel, South Iberian Peninsula, was carried out at three different sampling stations with known environmental LAS concentrations. PNECs obtained by the assessment factor approach with acute toxicity data were one to two orders of magnitude lower than those from the equilibrium partitioning method. On the other hand, when applying lower AFs to the estimated LC(10) values, the PNECs obtained by both approaches were more similar. Environmental risk assessment carried out with the estimated PNECs in a site specific environment with known sediment LAS concentrations revealed that PNECs obtained with acute toxicity data were over conservative whereas those obtained with AF=10 on LC(10) data and EPM produced more realistic results in accordance with field observations carried out in the study area.     

Enchytraeus albidus (Enchytraeidae): a test organism in a standardised avoidance test? Effects of different chemical substances

Enchytraeids (Enchytraeus albidus) directly improve the pore structure of the soil and are indirectly involved in regulating the degradation of organic matter. Due to their behavior they are able to avoid unfavorable environmental conditions. Avoidance tests allow a first assessment of toxicity of a contaminated or spiked soil within 48 h, by using the reaction of the enchytraeids as measurement endpoint. In this period, the organisms can choose between the control soil and the test soil. In the tests reported here, enchytraeids were exposed to LUFA 2.2 soil spiked with the following set of toxic substances: copper chloride, zinc chloride, cadmium chloride, phenmedipham, benomyl, carbendazim, dimethoate, atrazine, pentachlorophenol, chlorpyriphos, lindane, TBTO, Linear Alkylbenzene Sulfonates (LAS) and boric acid. Different chemical concentrations were tested. EC50s ranged from 8 mg/kg (Carbendazim) to >1000 mg/kg (e.g. LAS). While the tested heavy metals showed clear dose-response relationships, the effect pattern differed considerably in the tests with organic chemicals, e.g. no avoidance behaviour was observed in LAS, even at very high doses. Here we proposed to standardize the Enchytraeid avoidance test in a way similar to what is currently done for the earthworm and collembolan avoidance tests by the International Standardisation Organisation (ISO).     

Toxic effects of waterborne polychlorinated biphenyls and sex differences in an endangered goodeid fish (Girardinichthys viviparus)

Polychlorinated biphenyls (PCBs) elicit toxic effects in different species. PCBs undergo biotransformation by enzymes associated with the mixed functional oxidase system, such as cytochrome P450 (cyt P450), this biotransformation being sex-dependent. No other metabolic pathways are known, however, in connection with this process. Thus, the present study aims to evaluate the effects of waterborne PCBs at sublethal nominal concentrations (0.92 mg PCBs/L) on the black-fin goodeid Girardinichthys viviparus, an endangered fish native to the Valley of Mexico, as well as any sex differences related to PCB biotransformation. Eight-month-old adult fish born in the laboratory were exposed for 1, 2, 4, 8 and 16 days to half the LC(0) (calculated concentration at which no deaths occurred after 96 h) determined by an acute toxicity test. Specimens were sacrificed following exposure and the liver was used to evaluate different biomarkers: cyt P450 concentration and alcohol dehydrogenase (ADH) and ethoxyresorufin O-deethylase (EROD) activities. Results show sexual differentiation with regard to all biomarkers in both the control group and PCB-treated fish, with higher values found in males. The induction rate of cyt P450 remained constant throughout the study in males. In females, induction peaked on day 4, coinciding with maximum EROD activity, and fell significantly thereafter. EROD was lower in PCB-treated males than in the control group, but was greater in magnitude. ADH was significantly induced in both sexes from day 2 to day 16 of exposure. The highest response as compared to the control group occurred on day 8 in females. A correlation was found between ADH activity and exposure to PCBs. Three possible action mechanisms, operating either individually or concurrently, are proposed.     

Genotoxic and biochemical responses in caged eel (Anguilla anguilla L.) after short-term exposure to harbour waters

European eel (Anguilla anguilla L.) were caged and exposed in situ for 8 and 48 h to the Aveiro offward fishing harbour water (HW) and to clean seawater under laboratory conditions (Control). Eel liver biotransformation (Phase I) was measured as ethoxyresorufin-O-deethylase (EROD) activity, cytochrome P450 (P450) and glutathione S-transferase (GST) activity (Phase II). Genotoxic responses were determined as blood, liver and kidney DNA strand breaks as well as erythrocytic nuclear abnormalities (ENAs). HW failed to significant increase liver EROD, GST activities and ENA frequency. Nevertheless, P450 content was significantly increased after 8 and 48 h exposure. Genotoxicity measured as DNA integrity decrease was found in blood after 8 and 48 h exposure to HW, whereas in liver and kidney, it was observed after 48 h exposure to HW. Blood, kidney and liver genotoxicity may be due to the presence of polycyclic aromatic hydrocarbons (PAHs) which are genotoxic compounds and the main HW organic contaminants.     

Fly ash leachate induces oxidative stress in freshwater fish Channa punctata (Bloch)

Oxidative stress inducing potential of fly ash leachate (FAL) was studied in a freshwater fish, Channa punctata (Bloch). Fish were exposed to fly ash leachate for 24 h and lipid peroxidation (LPO) was studied as a marker of oxidative stress. Catalase (CAT), glutathione S-transferase (GST) activities and levels of reduced glutathione (GSH) were also estimated in the exposed fish. FAL (1 ml/l) induced LPO in all the organs and most prominent response was in the gill. It also caused induction of enzymes and glutathione. Liver showed highest level of induction of enzyme activities. The results of this study demonstrate that fly ash constituents have potential to induce oxidative stress in fish and gills are the most vulnerable organs. It is also suggested that in case of exposure to FAL, along with LPO antioxidant defense is also activated to counteract the reactive oxygen species (ROS) at least partly in the initial stages of exposure.     

Heavy metals in fish (Solea vulgaris, Anguilla anguilla and Liza aurata) from salt marshes on the southern Atlantic coast of Spain

Comparisons were made of metal concentrations in water and sediment with those in the muscle and livers of three species of fish caught in four seawater reservoirs (two in the Odiel estuary and two in the Bay of Cádiz). The concentrations of a large number of metals in the water, sediment and fish were higher in the Odiel reservoirs than in those in Cádiz. We found high metal-enrichment factors in the livers as compared to muscle (over 100 for Fe and Cu and around 5 for Zn, Ni, Cd and Pb). The three fish species showed differences in metal content. For example, eels accumulated more metals in muscle and grey mullet in the liver. The metal levels found in muscle in the three species were below the legal limits for human consumption, although Cu in the liver was above the limit in the three species taken from the Odiel reservoirs, and Zn levels in liver were over the maximum in eels from one of the Odiel marshes. Significant correlations (p<0.05) were obtained for the levels of numerous metals in water, sediment and fish.     

Fate, behavior and effects of surfactants and their degradation products in the environment

Surfactants are widely used in household and industrial products. After use, surfactants as well as their products are mainly discharged into sewage treatment plants and then dispersed into the environment through effluent discharge into surface waters and sludge disposal on lands. Surfactants have different behavior and fate in the environment. Nonionic and cationic surfactants had much higher sorption on soil and sediment than anionic surfactants such as LAS. Most surfactants can be degraded by microbes in the environment although some surfactants such as LAS and DTDMAC as well as alkylphenols may be persistent under anaerobic conditions. LAS were found to degrade in sludge amended soils with a half-lives of 7 to 33 days. Most surfactants are not acutely toxic to organisms at environmental concentrations and aquatic chronic toxicity of surfactants occurred at concentrations usually greater than 0.1 mg/L. However, alkylphenols have shown to be capable of inducing the production of vitellogenin in male fish at a concentration as low as 5 microg/L. More toxicity data are needed to assess the effects on terrestrial organisms such as plants.     

Essential and non-essential trace metals in scalp hair of men chronically exposed to volcanogenic metals in the Azores, Portugal

Volcanoes produce and release large amounts of toxicants, and the concentration of metals in hair can be used as a biomarker of exposure to trace metals. In order to investigate whether humans exposed to volcanic emissions demonstrate higher concentrations of essential and non-essential trace metals, scalp hair of men (3-89 years) living in two areas of the Azores, one exposed to volcanic emissions and the other not, was sampled, and their content in Cd, Cu, Pb, Rb, Se, and Zn was quantified by using High Resolution Inductively Coupled Plasma Mass Spectrometry. In average, men exposed to volcanic emissions presented higher concentrations of Cd (96.9 ppb), Cu (16.2 ppm), Pb (3417.6 ppb), Rb (216.3 ppb), and Zn (242.8 ppm), but not Se (469.6 ppb). Also, strong and significant correlations were found between Cd-Rb and Pb-Rb in the exposed men. In conclusion, humans living chronically exposed to volcanic emissions show high concentrations of essential and non-essential trace metals in scalp hair, and is suggested that this type of exposure may be as harmful as living close to industrial facilities.     

Naphthalene and beta-naphthoflavone effects on Anguilla anguilla L. hepatic metabolism and erythrocytic nuclear abnormalities

The effects of a polycyclic aromatic hydrocarbon (PAH) such as naphthalene (NAP)--an environmental contaminant--and beta-naphthoflavone (BNF)--a model substance (PAH-like compound)--were investigated in European eel (Anguilla anguilla L.) over 3-, 6-, and 9-day exposure (0.1-2.7 microM). Both xenobiotics revealed to be strong biotransformation (phase I) inducers. After 3-day exposure, liver ethoxyresorufin O-deethylase (EROD) activity was significantly increased by all NAP and BNF tested concentrations. At 6 and 9 days, liver EROD activity was significantly induced mainly by the highest NAP and BNF concentrations. Liver cytochrome P450 content was significantly induced after 3-day exposure to 0.9 and 2.7 microM BNF and 9-day exposure to 0.1, 0.3 and 0.9 microM NAP. Liver alanine transaminase (ALT) activity was measured as an indicator of hepatic health condition, revealing a significant decrease after 6-day exposure to 0.9 microM BNF. Genotoxicity measured as erythrocytic nuclear abnormalities (ENA) was detected in all BNF treated fish on day 6, whereas on day 9, ENA frequencies returned to control levels, significantly decreasing at 0.9 microM BNF exposure. Immature erythrocytes (IE) frequency demonstrated a decreasing tendency along the BNF experiment and concomitantly with the above ENA response. The present experimental results elect EROD activity in A. anguilla as a useful short- to medium-term biomarker of exposure to both PAH and PAH-like compounds. However, some problems can emerge in the presence of high xenobiotic concentrations. Concerning genotoxicity, it is hypothesized that ENA response depends on different factors such as the exhaustion of the detoxification process, the balance erythropoiesis/erythrocytic catabolism and the DNA repairing capacity.     

Disposition and metabolic profiling of [14C]-decabromodiphenyl ether in pregnant Wistar rats

Fully brominated diphenyl ether, decabromodiphenyl ether (DBDE), is one of the most widely used brominated flame retardants worldwide. Little data is available about the metabolic fate of DBDE in animal models and nothing at all about the extent of foetal exposure. In this work, pregnant Wistar rats were force-fed with 99.8% pure [14C]-DBDE over 96 h at a late stage of gestation (days 16 to 19). More than 19% of the administered dose was recovered in tissues and carcasses, demonstrating efficient absorption of DBDE despite its high molecular weight and low solubility. The highest concentrations of DBDE residues were found in endocrine glands (adrenals, ovaries) and in the liver, with lower values recorded for fat. In all tissue extracts, most of the radioactivity was associated with unchanged DBDE. The use of high-grade purity [14C]-DBDE allowed quantification of several metabolites present both in maternal tissues and in foetuses. These biotransformation products accounted for 9-27% of the extractable radioactivity in tissues and 14% of that in foetuses. Three nona-BDEs and one octa-BDE were identified by LC-APPI/MS. The unequivocal characterisation of a hydroxylated octa-BDE isolated from liver was confirmed by NMR. In rat, the main metabolic pathways of DBDE are debromination and oxidation. DBDE, and very likely most of its metabolites, are able to cross the placental barrier in rat. Metabolic profiles, obtained in vivo for the first time, demonstrated the presence of DBDE and major biotransformation products in endocrine glands as well as in foetuses. The biological activity of these metabolites still needs to be assessed in order to better understand the potential toxicity of DBDE.     

Colonized beads as inoculum for marine biodegradability assessment: Application to Linear Alkylbenzene Sulfonate

An innovative biodegradation test system was developed in order to fill the current gap for cost effective and environmentally relevant tools to assess marine biodegradability. Glass beads were colonized by a biofilm in an open flow-through system of seawater with continuous pre-exposure to Linear Alkylbenzene Sulfonate (LAS) (20 μg/L). Thereafter, such colonized beads were added as inoculum in different test systems. [¹⁴C]-LAS (5–100 μg/L) was added and primary and ultimate biodegradation were assessed. The bacterial density collected on the beads (10⁹ bact./mL beads) was ca. 3 orders of magnitude higher than the typical seawater content. The LAS mineralization lag phase duration decreased from 55 to < 1 days and the mineralization extent increased from 53 to 90% as the colonized beads volume increased from 10 to 275 mL. This is the first demonstration of marine bacteria's ability to mineralize LAS. On the opposite, less than 13% LAS was mineralized in seawater only. The colonized beads possibly enhanced the probability to encounter the full degraders' consortium in a low volume of seawater (100 mL).     

Distribution and dissipation pathways of nonylphenol polyethoxylates in the Yellow River: Site investigation and lab-scale studies

Spatial distribution of nonylphenol polyethoxylates (NPEOs) and nonylphenol (NP) was investigated in a field study in Lanzhou Reach of the Yellow River. NPEOs and their metabolites were found in the river, with the maximum dissolved concentrations of 6.38 nmol/L for NPEOs, 0.19 nmol/L for nonylphenol ethoxy acetic acids (NPECs) and 0.79 nmol/L for NP, respectively. The maximum concentrations in the sediment and suspended particle samples were 1.50 and 5.09 nmol/g for NPEOs and NP, respectively. The effects of particles, light and microorganism on the dissipation of NPEOs in the river water were investigated based on lab-scale experiments. When natural particles were removed, 72% and 22% degradation of NPEOs were achieved at 120 h in non-sterile and sterile conditions with light, respectively. Different concentrations of NPECs were also observed in these experiments. When suspended particle matters (SPMs) were present, about 38-50% of NPEOs were sorbed to the particulate phase in only 1 h. As a result, the degradation of NPEOs and production of NPECs were inhibited. However, the combined sorption and degradation in the presence of SPMs resulted in lower dissolved NPEO concentrations than those in the absence of SPMs. Biodegradation was the most important pathway for NPEOs degradation in the river water, while NPECs seemed to be produced through both biological and abiological pathways.     

Sources of hydrocarbons in sediments of the Mandovi estuary and the Marmugoa harbour, west coast of India

Surface sediments were collected from various locations of the Mandovi estuary and the Marmugoa harbour. Sediments were analysed for organic carbon (OC), total lipids, n-alkanes concentration and composition. Concentrations of OC, total lipids and n-alkanes varied spatially and ranged from 1 to 2.5%, 176 to 1413 microg/g dry weight (dw) sediments, and 0.8 to 3.2 microg/g dw sediments of the Mandovi estuary, respectively; and from 0.6 to 2.9%, 233 to 1448 microg/g dw sediments, and 1.6 to 10.7 microg/g dw sediments in the Marmugoa harbour, respectively. Long chain, odd carbon n-alkanes (C(23)-C(33)) in the Mandovi estuary, whereas short chain, even carbon n-alkanes (C(11)-C(21)) in the Marmugoa harbour sediments were more abundant. The total HC concentrations, n-alkane composition, CPI, UCM and other evaluation indices suggest the dominance of terrestrial hydrocarbons in the estuarine while petroleum derived hydrocarbons in the harbour sediments. This conclusion was further supported by the abundance of hopanes with C(29) to C(34) alpha, beta compounds and steranes with C(27), C(28) and C(29) compounds in the harbour sediments.     

Assessment of seasonal variability of biomarkers in three-spined stickleback (Gasterosteus aculeatus L.) from a low contaminated stream: implication for environmental biomonitoring

In this study, wild three-spined sticklebacks were sampled every six weeks, between April and October, in a low contaminated stream. For all fish, physiological indexes, such as condition factor, hepato-, gonado- and nephro-somatic index were calculated to determine fish condition and reproductive status. Moreover, a set of biomarkers including biotransformation enzymes, oxidative stress parameters, neurotoxicity and endocrine disruption markers was measured. The results allowed to determine biomarker variability due to fish gender or sampling season. For example, 7-ethoxyresorufin-O-deethylase activity, glutathione peroxidase as well as vitellogenin and spiggin exhibited strong gender differences. Conversely, lipoperoxidation and acethylcholinesterase activity were characterised by a lack of gender and seasonal variation, and can be considered as more robust parameters for a field application. The present work allowed to establish practical guideline for biomarker measurements in wild sticklebacks and to define a reference system which can be used to analyze variations in future monitoring studies.     

Natural and anthropogenic hydrocarbon inputs to sediments of Patos Lagoon Estuary, Brazil

The Patos Lagoon Estuary, southern Brazil, is an area of environmental interest not only because of tourism, but also because of the presence of the second major port of Brazil, with the related industrial and shipping activities. Thus, potential hydrocarbon pollution was examined in this study. Sediment samples were collected at 10 sites in the estuary, extracted, and analyzed by GC-FID and GC-MS for composition and concentration of the following organic geochemical markers: normal and isoprenoid alkanes, petroleum biomarkers, linear alkylbenzenes (LABs), and polycyclic aromatic hydrocarbons (PAHs). The total concentrations varied from 1.1 to 129.6 microg g(-1) for aliphatic hydrocarbons, from 17.8 to 4510.6 ng g(-1) for petroleum biomarkers, from 3.2 to 1601.9 ng g(-1) for LABs, and from 37.7 to 11,779.9 ng g(-1) for PAHs. Natural hydrocarbons were mainly derived from planktonic inputs due to a usual development of blooms in the estuary. Terrestrial plant wax compounds prevailed at sites located far from Rio Grande City and subject to stronger currents. Anthropogenic hydrocarbons are related to combustion/pyrolysis processes of fossil fuel, release of unburned oil products and domestic/industrial waste outfalls. Anthropogenic hydrocarbon inputs were more apparent at sites associated with industrial discharges (petroleum distributor and refinery), shipping activities (dry docking), and sewage outfalls (sewage). The overall concentrations of anthropogenic hydrocarbons revealed moderate to high hydrocarbon pollution in the study area.     

Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids,toxic isocyanic acid and carbon monoxide

In the north west Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October–November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r ≥ 0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62 ± 0.18 ppb), benzene (2.51 ± 0.28 ppb), toluene (3.72 ± 0.41 ppb), C8-aromatics (2.88 ± 0.30 ppb), C9-aromatics (1.55 ± 0.19 ppb) and CO (552 ± 113 ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97 ± 0.17 ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6 ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of benzene and ensure compliance with the NAAQS. Calculations of excessive lifetime cancer risk due to benzene amount to 25 and 10 per million inhabitants for children and adults, respectively, exceeding the USEPA threshold of 1 per million inhabitants. Annual exposure to isocyanic acid was close to 1 ppb, the concentration considered to be sufficient to enhance risks for cardiovascular diseases and cataracts. This study makes a case for urgent mitigation of post-harvest paddy residue fires as the unknown synergistic effect of multi-pollutant exposure due to emissions from this anthropogenic source may be posing grave health risks to the population of the N.W. IGP.     

Biotransformation, stress and genotoxic effects of 17beta-estradiol in juvenile sea bass (Dicentrarchus labrax L.)

The effects of 17beta-estradiol (E(2)) on fish became a matter of concern, since significant levels of this hormone were detected in the aquatic environment released mainly by domestic sewage treatment plants. In this perspective, the current study was focused on E(2) effects upon biotransformation, stress and genotoxic responses of juvenile Dicentrarchus labrax L. (sea bass). Fish were exposed to E(2) during 10 days in two different ways: water diluted (200 ng/L or 2,000 ng/L) and i.p. injected (0.5 mg/kg or 5 mg/kg). A battery of biological responses was evaluated: liver ethoxyresorufin-O-deethylase (EROD) and alanine transaminase (ALT) activities, liver somatic index (LSI), plasma cortisol, glucose and lactate concentrations, as well as erythrocytic nuclear abnormalities (ENA). All the exposure conditions induced endocrine disruption, measured as plasma cortisol decrease, and genotoxicity, measured as ENA increase. Thus, no differences were detected either between different exposure routes or tested concentrations. Concerning liver EROD and ALT activities, as well as plasma glucose and lactate concentrations no differences were found between treated and control groups. LSI was the only parameter to respond differently in the two exposure routes, as only E(2) water diluted induced a significant increase in this hepatic indicator.     

长江口口门区潮下带水域鱼类群落组成的季节变化

根据2006～2007年对长江口口门区潮下带鱼类的监测数据,分析了该水域鱼类群落组成的季节变化特征。结果表明：本次调查采获鱼类42种,隶属21科。生态类群以海洋鱼类种类最多（27种）,其次为河口定居种（10种）,而淡水鱼类、溯河产卵洄游鱼类和降海产卵洄游鱼类种类数很低。S1站点和S2站点类似,均以棘头梅童鱼（Collichthys lucidus）、刀鲚（Coilia ectenes）、龙头鱼（Harpodon nehereus）为优势种。两站点鱼类群落在空间上无显著差异,而时间上均有明显的季节变化,冬季和初春的样品聚为一组（Ⅰ组）,夏、秋季的样品聚为一组（Ⅱ组）。通过SIMPER分析可知,两组间的平均相异性较高,达7303,共有17种鱼类对组间的贡献超过90%,如日本鳗鲡（Anguilla japonica）、棘头梅童鱼、矛尾虾虎鱼（Chaeturichthys stigmatias）、刀鲚、焦氏舌鳎（Cynoglossus joyneri）、龙头鱼等。