Distribution and dynamics of larval populations of Anopheles messeae and A. atroparvus in the delta of the rivers Rhine and Meuse,The Netherlands

The distribution and ecology of mosquitoes of the Anopheles maculipennis complex were studied in the delta of the rivers Rhine and Meuse in the southwest of The Netherlands. The study area was previously malarious, with A. atroparvus being the only vector. 125 potential aquatic habitats of A. maculipennis were sampled, of which 47 (37.6%) contained larvae of this species complex. Larval densities varied from 7.4-325.93 larvae m-2. There was no correlation between chlorinity (@1000) of the water and presence and/or density of larvae. The presence of A. maculipennis was not associated with one particular aquatic floristic habitat, although larvae were often found together with floating algae (Enteromorpha spp.). Larvae were not found in areas experiencing tidal flooding. A newly developed PCR method was used for identification of the mosquito sibling species. Of 150 larvae examined, only 4 were identified as A. atroparvus. All other larvae examined were A. messeae. Adult mosquitoes were identified as A. messeae and 30 wild-caught mosquitoes had fed on domestic animals. Because most anophelines found in 1999 were A. messeae, it is concluded that the study area has undergone a dramatic ecological change since the previous anopheline investigations in 1935, causing the near extinction of A. atroparvus. This species was the only malaria vector in The Netherlands and therefore it is not expected that malaria can return to its former endemic status in the coastal areas of The Netherlands.     

Biomonitoring of heavy metals in the Western European Rivers Rhine and Meuse using the freshwater mussel Dreissena polymorpha

Since 1976, active and passive biological monitoring programs using the freshwater mussel Dreissena polymorpha have been carried out to study trends in the bioavailability of heavy metals in the rivers Rhine and Meuse. The Cd concentration in mussels exposed in the river Rhine has decreased from 74 mg kg(-1) in 1976 to 1.5 mg kg(-1) in 1988. In the river Meuse, however, the Cd concentration in Dreissena polymorpha has increased from 6 mg/kg (-1) to 22 mg kg(-1). Cu concentrations in mussels have not changed. Comparison of heavy metal concentrations in mussels from Lake Heerhugowaard, Lake Markermeer, Lake Maarsseveen and the river Dieze demonstrated that background concentrations for Cu, Zn, Cd and Pb in Dreissena polymorpha are about 12, 110, 1 and 0.5 mg kg(-1), respectively. Mussels from these four locations showed seasonal variation in heavy metal concentrations. This may be caused by both changes in the bioavailability of the metals and by the annual growth and reproductive cycle of the mussels. Therefore, one should take care that animals are collected at the same location and in the same section in long-term active biological monitoring programs.     

Dredging impact on an urbanized Florida bayou: effects on benthos and algal-periphyton.

Environmental effects of dredging events have been uncommonly reported for shallow, residential estuaries characteristic of the Gulf of Mexico region. The objective of this study was to determine the impact of hydraulic dredging on an urbanized estuary. Physicochemical quality, benthic community composition, whole sediment toxicity, periphytic algal community composition and trace metal tissue quality were determined prior to and after dredging. The effects on surface water pH, dissolved oxygen, and temperature were negligible but photosynthetically active radiation was decreased at several stations. Dredging significantly reduced benthic diversity and density (P < 0.05). However, the sediments were not acutely toxic to the epibenthic, Americamysis bahia (formerly Mysidopsis bahia); survival averaged 93% (post-dredging) and to 98% (pre-dredging). There were several post-dredging taxonomic structural changes in the diatom-dominated, periphyton community but differences in mean density and three diversity indices were not significant. Trace metal concentration in periphyton after dredging were reduced from an average of 4-65% and significantly for mercury, zinc and chromium in several areas. It was concluded that the environmental impact of small-scale dredging events in urbanized near-coastal areas, based on the selected parameters, are likely to be localized and of short-term environmental consequence. The choice of the target biota, response parameters and chemical analysis are important considerations in the environmental impact assessment of these periodic episodic events.     

上海河流氮负荷的年际变化及其水体富营养化的原因探讨

利用1990-2002年水质监测数据,分析了上海河流水体中氮负荷(总氮和氨氮)的年际变化特征：从整体上来看,上海河流水体氮负荷较大,氮污染严重:苏州河、黄浦江下游河段氮负荷明显高于上游河段,市区河流氮负荷明显高于郊区河流;从年际变化上看,苏州河、黄浦江、市区河流(除龙华港)水体历年氮含量有降低趋势,郊区河流水体历年氮含量有增长趋势。在此基础上,从六个方面讨论了造成上海河流水体富营养化的原因,以期为上海市河流综合整治的规划决策提供重要的科学依据。     

Occurrence and temporal variations of TMDD in the river Rhine,Germany

Background, aim, and scope

The chemical substance 2,4,7,9-tetramethyl-5-decyne-4,7-diol (TMDD) is a non-ionic surfactant used as an industrial defoaming agent and in various other applications. Its commercial name is Surynol 104® and the related ethoxylates are also available as Surfynol® 420, 440, 465 and 485 which are characterized by different grades of ethoxylation of TMDD at both hydroxyl functional groups. TMDD and its ethoxylates offer several advantages in waterborne industrial applications in coatings, inks, adhesives as well as in paper industries. TMDD and its ethoxylates can be expected to reach the aquatic environment due its widespread use and its physico-chemical properties. TMDD has previously been detected in several rivers of Germany with concentrations up to 2.5?µg/L. In the United States, TMDD was also detected in drinking water. However, detailed studies about its presence and distribution in the aquatic environment have not been carried out so far. The aim of the present study was the analysis of the spatial and temporal concentration variations of TMDD in the river Rhine at the Rheingütestation Worms (443.3 km). Moreover, the transported load in the Rhine was investigated during two entire days and 7 weeks between November 2007 and January 2008.

Materials and methods

The sampling was carried out at three different sampling points across the river. Sampling point MWL1 is located in the left part of the river, MWL2 in the middle part, and MWL4 in the right part. One more sampling site (MWL3) was run by the monitoring station until the end of 2006, but was put out of service due to financial constrains. The water at the left side of the river Rhine (MWL1) is influenced by sewage from a big chemical plant in Ludwigshafen and by the sewage water from this city. The water at the right side of the river Rhine (MWL4) is largely composed of the water inflow from river Neckar, discharging into Rhine 14.9 km upstream from the sampling point and of communal and industrial wastewater from the city Mannheim. The water from the middle of the river (MWL2) is largely composed of water from the upper Rhine. Water samples were collected in 1-L bottles by an automatic sampler. The water samples were concentrated by use of solid-phase extraction (SPE) using Bond Elut PPL cartridges and quantified by use of gas chromatography-mass spectrometry (GC-MS). The quantification was carried out with the internal standard method. Based on these results, concentration variations were determined for the day profiles and week profiles. The total number of analyzed samples was 219.

Results

The results of this study provide information on the temporal concentration variability of TMDD in river Rhine in a cross section at one particular sampling point (443.3 km). TMDD was detected in all analyzed water samples at high concentrations. The mean concentrations during the 2 days were 314 ng/L in MWL1, 246 ng/L in MWL2, and 286 ng/L in MWL4. The variation of concentrations was low in the day profiles. In the week profiles, a trend of increasing TMDD concentrations was detected particularly in January 2008, when TMDD concentrations reached values up to 1,330 ng/L in MWL1. The mean TMDD concentrations during the week profiles were 540 ng/L in MWL1, 484 ng/L in MWL2, and 576 ng/L in MWL4. The loads of TMDD were also determined and revealed to be comparable in all three sections of the river. The chemical plant located at the left side of the Rhine is not contributing additional TMDD to the river. The load of TMDD has been determined to be 62.8 kg/d on average during the entire period. By extrapolation of data obtained from seven week profiles the annual load was calculated to 23 t/a.

Discussion

The permanent high TMDD concentrations during the investigation period indicate an almost constant discharge of TMDD into the river. This observation argues for effluents of municipal wastewater treatment plants as the most likely source of TMDD in the river. Another possible source might be the degradation of ethoxylates of TMDD (Surfynol® series 400), in the WWTPs under formation of TMDD followed by discharge into the river. TMDD has to be considered as a high-production-volume (HPV) chemical based on the high concentrations found in this study. In the United States, TMDD is already in the list of HPV chemicals from the Environmental Protection Agency (EPA). However, the amount of TMDD production in Europe is unknown so far and also the biodegradation rates of TMDD in WWTPs have not been investigated.

Conclusions

TMDD was found in high concentrations during the entire sampling period in the Rhine river at the three sampling points. During the sampling period, TMDD concentrations remained constant in each part of the river. These results show that TMDD is uniformly distributed in the water collected at three sampling points located across the river. ‘Waves’ of exceptionally high concentrations of TMDD could not be detected during the sampling period. These results indicate that the effluents of WWTPs have to be considered as the most important sources of TMDD in river Rhine.

Recommendations and perspectives

Based also on the occurrence of TMDD in different surface waters of Germany with concentrations up to 2,500 ng/L and its presence in drinking water in the USA, more detailed investigations regarding its sources and distribution in the aquatic environment are required. Moreover, the knowledge with respect to its ecotoxicity and its biodegradation pathway is scarce and has to be gained in more detail. Further research is necessary to investigate the rate of elimination of TMDD in municipal and industrial wastewater treatment plants in order to clarify the degradation rate of TMDD and to determine to which extent effluents of WWTPs contribute to the input of TMDD into surface waters. Supplementary studies are needed to clarify whether the ethoxylates of TMDD (known as Surfynol 400® series) are hydrolyzed in the aquatic environment resulting in formation of TMDD similar to the well known cleavage of nonylphenol ethoxylates into nonylphenols. The stability of TMDD under anaerobic conditions in groundwater is also unknown and should be studied.

     

Analysis of the effects of rotational larviciding on aquatic fauna of two Guinean rivers: the case of permethrin.

Within the Onchocerciasis Control Programme about 50,000 km of west African rivers have been regularly sprayed with larvicides to control the vector of dermal filariasis caused by Onchocerca volvulus. Since the beginning of the programme invertebrates and fish data were collected to monitor adverse effects on non-target organisms. The regular series of biological and hydrological data collected in two Guinean rivers were analysed to evaluate the effects of rotational larviciding with particular attention to permethrin, as preliminary acute toxicology tests and semi-field experiments suggest it has stronger effects on non-target fauna in respect to other larvicides. Invertebrates and fish variations in biomass and species richness are seasonal and flow-related and the results presented here do not support any evidence of specific effects of permethrin application on the biological targets monitored. Larvicide applications influence community structures, putting pressure on some taxonomic groups, causing, for example, the rarefaction of some taxa. In spite of the above results, the scarcity of some invertebrate systematic units does not result in a significant reduction of total invertebrate density because of the corresponding increase in other systematic units. In nature the studied aquatic communities would rarely be in equilibrium because of frequent natural stresses, such as drought and spate events, the biological variations discussed are to be considered ecologically acceptable.     

Endocrine-disrupting chemicals in coastal lagoons of the Po River delta: sediment contamination,bioaccumulation and effects on Manila clams

The large estuary that the River Po forms at its confluence into the Adriatic Sea comprises a multitude of transitional environments, including coastal lagoons. This complex system receives the nutrients transported by the River Po but also its load of chemical contaminants, which may pose a substantial (eco)toxicological risk. Despite the high ecological and economic importance of these vulnerable environments, there is a substantial lack of information on this risk. In light of the recent amendments of the European Water Framework Directive (2013/39/EU), the present study investigated the sediment contamination of six coastal lagoons of the Po delta and its effects on Manila clams (Ruditapes philippinarum), exposed in situ for 3 months. Sediment contamination and clam bioaccumulation of a wide range of chemicals, i.e. trace metals (Cd, Cr, Ni, Hg, Pb, As), polybrominated diphenyl ethers (PBDEs), alkylphenols (APs), organochlorine compounds (PCBs, DDTs), polycyclic aromatic hydrocarbons (PAHs) and organotins (TPhT, TBT), suggested a southward increase related to the riverine transports. Where the River Po influence was more direct, the concentrations of contaminants were higher, with nonylphenol and BDE-209 exceeding sediment quality guidelines. Biometric indicators suggested the influence of contamination on organism health; an inverse relationship between PBDEs in sediments and clam condition index has been found, as well as different biota-sediment accumulation factors (BSAFs) in the lagoons.     

Distribution and sources of polyfluoroalkyl substances (PFAS) in the River Rhine watershed

The concentration profile of 40 polyfluoroalkyl substances (PFAS) in surface water along the River Rhine watershed from the Lake Constance to the North Sea was investigated. The aim of the study was to investigate the influence of point as well as diffuse sources, to estimate fluxes of PFAS into the North Sea and to identify replacement compounds of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). In addition, an interlaboratory comparison of the method performance was conducted. The PFAS pattern was dominated by perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) with concentrations up to 181 ng/L and 335 ng/L, respectively, which originated from industrial point sources. Fluxes of ΣPFAS were estimated to be ∼6 tonnes/year which is much higher than previous estimations. Both, the River Rhine and the River Scheldt, seem to act as important sources of PFAS into the North Sea.     

城市河流与湖库中痕量有机污染物的研究

通过采用ＧＤＸ－５０２富集,ＧＣ－ＭＳ分析,对城市河流、湖库中的痕量有机污染物进行分析,共检出５８种有机污染物,其中含有多种美国ＥＰＡ公布的重点污染物,从而为痕量有机污染物的研究建立了灵敏度高,分辨率好的测试方法。     

Analysis of volatile organic compounds, using the purge and trap injector coupled to a gas chromatograph/ion-trap mass spectrometer: review of the results in Dutch surface water of the Rhine, Meuse, Northern Delta Area and Westerscheldt, over the period 1992-1997

Volatile organic compounds are widely introduced into the Dutch aquatic environment. Liquid-liquid extraction and isolation by means of resins give poor recoveries for volatiles. In this study, a method has been developed to analyse these compounds with a purge and trap injection (PTI) coupled to a chromatograph/ion trap mass spectrometer. Volatile compounds are "purged" from the sample by carrier gas flow and transported through a condenser to a cooled trap. The bulk of liquid matrix is condensed in the condenser, while volatile compounds are left unaffected. The compounds of interest are trapped at a low temperature, by liquid nitrogen in the cooled trap of fused silica. Injection takes place by flash heating of the trap. The detection limits of the volatile compounds are in the range of 0.001-0.04 microgram l-1, in full spectrum mode. In this paper a review of the results in Dutch surface water of the Rhine, Meuse, Northern Delta Area and Westerscheldt, over the period 1992-1997, is presented. For calamities causing high levels of volatiles, the method is very useful. The compounds can be monitored over a certain period. In the Meuse, high levels of volatile organic compounds are observed. Diisopropyl ether at a maximum of 592 micrograms l-1.     

Stable isotope on the evaluation of water quality in the presence of WWTPs in rivers

Environmental Science and Pollution Research - We investigated the distribution of nitrogen compounds in Han River as well as two tributaries of Tancheon and Jungrangcheon. Particularly, we...     

Pesticide residues in rivers of a Brazilian Rain Forest Reserve: assessing potential concern for effects on aquatic life and human health

Pesticide residues in water, sediment, and fish samples from rivers of a Brazilian Rain Forest Reserve were measured in November 1998, March 1999, and January 2000. Concentrations of the individual pesticides were compared to ecotoxicological benchmarks based on acute toxicity tests, and to regulatory guidelines to determine the potential concern for effects on aquatic life and human health. Pesticides and metabolites were detected at all 7 sites surveyed. Residues of a total of 27 pesticides or metabolites were found in water and/or sediment samples and fish have accumulated some of the most persistent of these residues. Measured concentrations in water and sediment indicated concern for preservation of aquatic fauna. Several pesticides in water were above levels for drinking water recommended by Brazilian and/or European Union authorities, indicating also a concern for human health.     

Estimation of faecal pollution based on the amounts of urobilins in urban rivers

An attempt was made to establish a new indicator for faecal pollution in aquatic environments using a sensitive determination method for urobilins, which are only present in mammalian faeces and urine. Assessment of urobilin stability was followed by determination of the amount of urobilins in river water. When river water containing urobilins was shaken at room temperature, the number of total and faecal coliforms increased, while urobilins decreased only in small amounts, indicating that urobilin is relatively stable in river water and hence can serve as a useful indicator for the estimation of faecal pollution of river water. The amount of urobilins in the river waters increased steeply from the mid-point of a stream near a sewage treatment plant, while amounts in the upper stream were very low. The amount of urobilins in river water increased after rainfall. Findings suggested that urobilin, i.e. sewage, originated from the output of the sewage treatment plant and raw sewage.     

Historical marine ecology: examining the role of fisheries in changes in North Sea benthos

The organisms living on and in the sea floor, the benthos, represent an important ecological group. Although some (shellfish) have an economic value, most do not, and so little long-term data are available. We have identified three sources of historic benthic data for the North Sea, a regional sea that has been subjected to multiple human impacts for at least several hundred years. Each dataset has its limitations, but by their use together some issues emerge. Wider community shifts were observed in the shorter term and a number of extirpations at the scale of the North Sea were seen over longer time scales. The extirpated taxa share a number of characteristics consistent with an effect of fisheries such as fragile morphology. We must concentrate now on furthering our understanding of the ecological significance of shifts in dominance of particular functional units and protecting those habitats and species most vulnerable to fisheries-driven extirpation.     

Bioaccumulation of 51Cr, 63Ni and 14C in Baltic Sea benthos

The Baltic Sea is a species-poor, semi-enclosed, brackish sea, whose sediments contain a wide range of contaminants, including sediment-associated metals and radionuclides. In this study, we have examined and compared bioaccumulation kinetics and assimilation efficiencies of sediment-associated (51)Cr, (63)Ni and (14)C in three key benthic invertebrates (the deposit-feeding Monoporeia affinis, the facultative deposit-feeding Macoma baltica, and the omnivorous Halicryptus spinulosus). Our results demonstrate that (i) all radionuclides were accumulated, (ii) the different radionuclides were accumulated to various extents, (iii) small changes in organic carbon concentration can influence the accumulation, and (iv) the degree of accumulation differed only slightly between species. These processes, together with sediment resuspension and bioturbation, may remobilise trace metals from the sediment to the water and to higher trophic levels, and therefore should be taken into account in exposure models and ERAs.     

Laboratory shake flask batch tests can predict field biodegradation of aniline in the Rhine

The aim of this study was to compare degradation rates of aniline in laboratory shake flask simulation tests with field rates in the river Rhine. The combined events of a low flow situation in the Rhine and residual aniline concentrations in the effluent from the BASF treatment plant in Ludwigshafen temporarily higher than normal, made it possible to monitor aniline at trace concentrations in the river water downstream the wastewater outlet by means of a sensitive GC headspace analytical method. Aniline was analyzed along a downstream gradient and the dilution along the gradient was calculated from measurements of conductivity, sulfate and a non-readily biodegradable substance, 1,4-dioxane. Compensating dilution, field first-order degradation rate constants downstream the discharge of BASF were estimated at 1.8 day⁻¹ for two different dates with water temperatures of 21.9 and 14.7 °C, respectively. This field rate estimate was compared with results from 38 laboratory shake flask batch tests with Rhine water which averaged 1.5 day⁻¹ at 15 °C and 2.0 day⁻¹ at 20 °C. These results indicate that laboratory shake flask batch tests with low concentrations of test substance can be good predictors of degradation rates in natural water bodies––at least as ascertained here for short duration tests with readily degradable compounds among which aniline is a commonly used reference.     

Characteristics of mercury speciation in Minnesota rivers and streams

Patterns of mercury (Hg) speciation were examined in four Minnesota streams ranging from the main-stem Mississippi River to small tributaries in the basin. Filtered phase concentrations of methylmercury (MeHg), inorganic Hg (IHg), and dissolved organic carbon (DOC) were higher in all streams during a major summertime runoff event, and DOC was enriched with MeHg but not with IHg. Particulate-phase MeHg and IHg concentrations generally increased with total suspended solids (TSS) concentrations but the event data did not diverge greatly from the non-event data, suggesting that sources of suspended sediments in these streams did not vary significantly between event and non-event samplings. The dissolved fractions (filtered concentration/unfiltered concentration) of both MeHg and IHg increased with increasing DOC concentrations, but varied inversely with TSS concentrations. While MeHg typically constitutes only a minor portion of the total Hg (THg) in these streams, this contribution is not constant and can vary greatly over time in response to watershed inputs.     

Occurrence and determination of organic oxidants in rivers and wastewaters

Two iodometric methods for the concentration and analysis of water samples containing organic oxidants were applied to rivers and wastewaters in Illinois, Delaware, and Pennsylvania. Oxidant concentrations detected were as high as 2.5 § 10⁻⁵ M; the methods were capable of detecting as little as 10⁻⁸ M. Compounds possibly responsible for the observed oxidizing activity include N-chloro compounds, organic peroxides, or quinones.     

Biomarker responses as indication of contaminant effects in Oreochromis niloticus

The current study investigated oxidative stress parameters (enzymes activities, metallothionein content and lipid peroxidation) in freshwater fish, Oreochromis niloticus, tilapia exposure to Monjolinho River (in 4 months of year: January, April, July and November). One critical site in Monjolinho River (site B) was assessed in comparison to a reference site (site A). Water pH and oxygen concentration was lower than that recommended by CONAMA (Brazilian National Environmental Committee), resolution 357/2005 for protection of aquatic communities, and ammonium and the metals Cu, Zn, Mn and Fe (on all months) concentrations were higher than the maximum concentration recommended. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were significantly decreased in liver and muscle in tilapia from Monjolinho River, throughout the year, in relation to reference except in gills that SOD activity increased. Glutathione S-transferase (GST) activity was significantly increased in liver of the tilapia from Monjolinho River in all sites, in relation to reference except in gills that GST activity increased in July and decreased in November, suggesting that GST activity could be induced to neutralize the pollutants toxicity. On the other hand, GST activity was significantly decreased in white muscle indicating a toxic effect of pollutants, resulting in a decreased ability of tilapia to perform defense reactions associated to GSTs. The decrease of catalase (CAT) activity in gills of the O. niloticus together with the increase of SOD activity, could explain the increased lipid peroxidation (LPO) level in this organ. Metallothionein levels in liver and gills were significantly high in all sites. Results indicate that the exposure to metals caused severe damage to tissues; despite the consensually assumed antioxidant induction as a sign of exposure to contaminants the effects seem in part to be mediated by suppression of antioxidant system with SOD, CAT and GPx as potential candidates for tissues toxicity biomarkers of pollutants.     

中国北方城市内河水资源综合利用与调配方案研究——以胶州市城市内河为例

内河是城市的重要组成部分,而伴随着快速城镇化进程,城市内河原有的水文、生态节律都受到很大的扰动。针对胶州市水资源量相对有限、水环境质量较差的现状,以河道生态需水量理论为指导,以期通过实施科学的生态补水,逐步恢复城市内河的生态功能与城市景观功能。结果表明,胶州市城市内河以景观功能为主,经测算其生态需水量为36 486.9m3/d,而根据胶州市的相关发展规划,其污水处理厂中水回用能力为5万m3/d,可以满足生态补水工程的需求;根据生态补水工程实施后的污染物入河情况预测,实施生态补水后,胶州市城市内河水质基本达到《地表水环境质量标准》(GB 3838—2002)Ⅳ类标准,基本可消除水体黑臭等现象。