Microbial characteristics of marine sediments in bathing area along Pesaro-Gabicce coast (Italy): a preliminary study

AIMS: This paper evaluates the presence of human pathogen micro-organisms in marine sediments in a coastal area suitable for bathing. In addition, the grain size analysis was performed in order to correlate the characteristics of the sediments and the microbial content. METHODS AND RESULTS: The samples were collected in two small bays along the central Adriatic coast, where breakwaters had been built for the purpose of halting marine erosion. Faecal contamination indicators, Salmonella and Vibrio species, enteric viruses were investigated using standard techniques for isolation and identification. The grain size was determined using calibrated sieves and 'Sedigraph' device. In some samples, the faecal contamination indices overstepped legislative limits. Salmonella was never found. Vibrio and enteric viruses were isolated: the micro-organisms were preferentially abundant in fine sediments. CONCLUSIONs: Marine sediments can represent an important reservoir of allochthonous and marine micro-organisms and the microbial charge correlates with the characteristics of the sediments. SIGNIFICANCE AND IMPACT OF THE STUDY: This study indicates that it is important to analyse marine sediments before defining the quality of coastal areas.     

The use of antlers to monitor temporal variation in environmental lead levels: a case study from an industrialized area in Germany

In order to assess temporal changes in ambient lead levels, Pb concentrations were determined in roe deer (Capreolus capreolus) antlers (n=116) that had been collected in the industrialized area of Siegen (western Germany) in the period 1948–2000. Lead concentrations ranged between 0.3 and 166.3 mg/kg dry weight. An overall decline in antler Pb concentration occurred from the mid-1970s onward, and lead concentrations in the samples from the periods 1980–1989 and 1990–2000 were significantly lower than those in samples from previous periods. Our findings indicate a marked decline in lead exposure of the roe deer inhabiting the study area in the recent past. This decline is attributed to a decrease in atmospheric lead deposition, caused mainly by the phase-out of leaded gasoline, and, in addition, by a reduction of lead emissions from stationary sources. The results of the present study and of previous investigations demonstrate that analysis of antler samples obtained in an area over a certain period can be used to reconstruct temporal changes in environmental lead levels.     

Hierarchical bivariate time series models: a combined analysis of the effects of particulate matter on morbidity and mortality

In this paper we develop a hierarchical bivariate time series model to characterize the relationship between particulate matter less than 10 microns in aerodynamic diameter (PM10) and both mortality and hospital admissions for cardiovascular diseases. The model is applied to time series data on mortality and morbidity for 10 metropolitan areas in the United States from 1986 to 1993. We postulate that these time series should be related through a shared relationship with PM10. At the first stage of the hierarchy, we fit two seemingly unrelated Poisson regression models to produce city-specific estimates of the log relative rates of mortality and morbidity associated with exposure to PM10 within each location. The sample covariance matrix of the estimated log relative rates is obtained using a novel generalized estimating equation approach that takes into account the correlation between the mortality and morbidity time series. At the second stage, we combine information across locations to estimate overall log relative rates of mortality and morbidity and variation of the rates across cities. Using the combined information across the 10 locations we find that a 10 microg/m3 increase in average PM10 at the current day and previous day is associated with a 0.26% increase in mortality (95% posterior interval -0.37, 0.65), and a 0.71% increase in hospital admissions (95% posterior interval 0.35, 0.99). The log relative rates of mortality and morbidity have a similar degree of heterogeneity across cities: the posterior means of the between-city standard deviations of the mortality and morbidity air pollution effects are 0.42 (95% interval 0.05, 1.18), and 0.31 (95% interval 0.10, 0.89), respectively. The city-specific log relative rates of mortality and morbidity are estimated to have very low correlation, but the uncertainty in the correlation is very substantial (posterior mean = 0.20, 95% interval -0.89, 0.98). With the parameter estimates from the model, we can predict the hospitalization log relative rate for a new city for which hospitalization data are unavailable, using that city's estimated mortality relative rate. We illustrate this prediction using New York as an example.     

Diffuse atrazine pollution in German aquifers

Until its prohibition in Germany in 1991, atrazine was the mostfrequently applied herbicide in maize cultivation. Moreover, it was used in orchards andvineyards and as a total herbicide on non-cultivated grounds (railways, factory grounds).Later on, atrazine was substituted mainly by terbutylazine. Terbutylazine and terbutrynare the only s-triazines presently permitted in Germany. Nevertheless, atrazine and itsmetabolite desethylatrazine are by far the most abundant herbicides detected in near surfacegroundwater. This might be due to wash-outs from the pools of atrazine and its metabolitesfrom the soil into the groundwater or continuing illegal applications. Samples takenfrom maize fields in 1994 showed that 6.2% of 471 fields tested were treated with atrazinedespite the prohibition of its use. Nevertheless, the overall trend is in fact a slow decreasein atrazine concentrations where it is detected in groundwater and, simultaneously often aslight increase in desethylatrazine concentrations. But this is not the case forall sampling points, and increasing concentrations in several aquifers are observedas well. Factors governing the adsorption, degradation, persistence and the possible transferinto the aquifer and the current situation concerning atrazine occurrence in German aquiferswill be discussed.     

Spatial Distribution and Temporal Variance of Fish Communities in the Channelized and Regulated Vltava River (Central Europe)

Spatial distribution and temporal variations of fish communities in a channelized portion of the Vltava River (Central Europe) were investigated from May to October 1992. Fish abundance and species number were collected monthly during diel samples in the main channel and a large oxbow. To determine differences in fish communities we chose the low-flow period when maximal differences in physical environment between habitats are expected. Fish community patterns from the main channel and oxbow differed only in abundance of ecological groups; the main channel had higher abundance of rheophilic species, whereas eurytopic species were more abundant in the oxbow. However, our analysis revealed significant differences in temporal variations between habitats. Fish abundance usually varied unpredictably over day-night periods in the main channel, whereas in the oxbow we observed a pronounced peak in fish abundance from morning to mid-afternoon. Diel changes in fish abundance in the oxbow corresponded to occurrence of low dissolved oxygen during afternoon and night-time periods. The effect of oxygen depletion induced by strong organic pollution limited the oxbow suitability for fishes. Similar habitats are usually occupied by limnophilic and phytophilic species that were absent in our samples. Our results suggested that man-induced high variability of physical environment decreased variability in fish community.     

Physicochemical and morphological characterization of two small polluted streams in southwest Germany

As a supporting component of the VALIMARproject, physicochemical investigations wereconducted monthly from 1995 to 1999 at theKrähenbach/Aich stream system (two samplingsites) and at the Körsch stream (sixsampling sites). Several physicochemicalparameters were analysed continuously bydataloggers during the entire sampling period.Moreover, a selection of the most importantmorphological parameters of the stream wererecorded in 1998.The results of these physicochemicalinvestigations demonstrated that theKrähenbach/Aich system could becharacterized as a natural rhithral submontanecarbonate stream system that is welloxygenated. Low temporal variations in pH,conductivity and chloride occurred at allsampling sites in the Krähenbach whichcoincided with the geological conditions atthis test stream. Because of relatively lowconcentrations of organic and inorganiccompounds during the entire study period thesites AB and AC in the Krähenbach/Aichsystem were classified as slightly polluted.The morphological assessment of the streamindicated a moderately affected status atboth of these streams.Physicochemical and morphologicalinvestigations along the Körsch streamsystem (KA to KE including the tributary streamSulzbach) indicated a highly affected rhithralsubmontane carbonate system characterized byhigh water velocity, flow rate and dissolvedoxygen. The Körsch, however, differssignificantly with respect to watertemperature, conductivity, pH, BOD₅,nutrients, and chloride concentrations from theKrähenbach. As a result of differentanthropogenic inputs (e.g. several sewageplants, agriculture activities and waste waterdumping) the Körsch sites KA to KD wereclassified as critically to heavilypolluted. The morphological assessmentindicated a clearly affected to damagedstatus. The upstream site KE could becharacterized as slightly polluted and itsmorphological structure as moderatelyaffected.     

The effect of long-term mercury pollution on the soil microbial community

The effect of long-term exposure to mercury on the soil microbial community was investigated in soil from three different sites along a pollution gradient. The amount of total and bioavailable mercury was negatively correlated to the distance from the center of contamination. The size of the bacterial and protozoan populations was reduced in the most contaminated soil, whereas there was no significant difference in fungal biomass measured as chitinase activity. Based on the number of colony morphotypes, moreover, the culturable bacterial population was structurally less diverse and contained a higher proportion of resistant and fast-growing forms. The profiles of amplified 16S rDNA sequences obtained from community DNA by denaturating gradient gel electrophoresis (DGGE) also reflected the altered community structure and decreased diversity along the mercury gradient as expressed in terms of the number and abundance of bands. The functional potential of the microbial population measured as sole carbon source utilization by Ecoplates((R)) differed between the soils, but there was no change in the number of substrates utilized. The observed changes in the different soil microbial populations are probably a combination of both direct and indirect effects of the mercury contamination.     

厦门市海岸带水污染负荷估算及预测

综合采用灰色模型、曲线回归等预测方法,建立了基于厦门市海岸带特征的主要污染源水污染负荷估算及预测模型,并采用厦门市历年统计数据对模型加以验证.对厦门市近岸海域近10年的废水和主要污染物质排放量估算的结果表明:万元产值工业废水排放量呈逐年下降的趋势,而各污染物的排放总量却逐年缓慢增长;在点源污水排放总量预测中,约76%的氮、磷来自于生活污水;在非点源污染负荷中,农业非点源中的氮、磷负荷占较大比例,城市非点源污染负荷比例最小.2005年厦门海岸带各污染源产生的氮污染负荷大小比较结果为:生活污染源>农业非点源>工业污染源>旅游业污染源>城市非点源,磷污染负荷则为:农业非点源>生活污染源>工业污染源>旅游业污染源>城市非点源.     

植物的臭氧污染胁迫效应研究进展

近地面空气中的臭氧(O₃)属于二次污染物,是由氮氧化物(NO_x)和挥发性有机物(VOCs)等前体物在一定的环境条件下形成的。近年来,全球受O₃污染的区域增加,污染程度也日趋严重。O₃污染对植物的危害引起了国内外研究人员的广泛关注。众多研究发现,不同植物对O₃的敏感性不同,其大小主要取决于植物自身的特性及环境因素;O₃污染降低植物的净同化作用,减缓植物生长,改变同化物的分配,可对物种间的相互关系以及生态系统结构产生深远影响。该文在综述了国内外研究进展的基础上,提出我国在O₃污染研究领域应深入研究以下几个方面:1)选育具有对O₃污染抗性较强的植物尤其是作物品种;2)深入研究减轻O₃污染对植物危害的栽培管理措施;3)加强研究O₃污染对我国自然生态系统的影响;4)研究植被在治理O₃污染中的积极作用。