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131.
Alexandre Ciliberti Samuel Martin Eric Ferrandez Sara Belluco Benoit Rannou Céline Dussart Philippe Berny Vivian de Buffrenil 《Environmental science and pollution research international》2013,20(5):3107-3114
Using varanids as indicators of pollution in African continental wetlands was previously proposed. The present study aimed at understanding experimentally how monitors absorb and accumulate pollutants and how they are affected. The relevance of non-destructive sampling was also evaluated. Savannah monitors (Varanus exanthematicus) were orally exposed during 6 months to a mixture of lead, 4,4′-dichlorodiphenyltrichloroethane (4,4′-DDT) and chlorpyrifos-ethyl (CPF) or to the vehicle only. Proportionally to their mass, exposed monitors received the same dose: 20 then 10 mg lead?kg?1, 2 then 0.5 mg CPF?kg?1 and 4 mg 4,4′-DDT?kg?1. Individuals surviving contamination were euthanized after 4 or 6 months of experiment. Tissues were analysed for lead by atomic absorption spectrophotometry and for DDT and CPF by gas chromatography. Exposed monitors absorbed all three pollutants but only lead (essentially in bone, tail tips and phalanxes) and 4,4′-DDT plus its main metabolites (essentially in fat and liver) accumulated. CPF killed ten individuals. Clear correlations occurred between the total quantity of lead or 4,4′-DDT administered and concentrations in tissues. Tail tips and skin samples are recommended non-destructive indicators for lead and organochlorine pesticides contamination, respectively. This work confirms that monitors can be used as relevant indicators of environmental pollution by lead and organochlorine pesticides. Although varanids withstand heavy lead and DDT contamination, our results suggest that CPF can be lethal at very low doses to the herpetofauna and emphasize the importance of considering all taxa in impact assessment studies, including reptiles. 相似文献
132.
Uzochukwu C. Ugochukwu Martin D. Jones Ian M. Head David A. C. Manning Claire I. Fialips 《Environmental science and pollution research international》2013,20(9):6445-6454
The compositional changes of saturates, aromatics, resins and asphaltenes (SARA) fractions in aqueous clay/oil microcosm experiments with a hydrocarbon-degrading microorganism community were analysed using Iatroscan. The clay mineral samples used in this study were organomontmorillonite, acid-activated montmorillonite and K, Ca, Zn and Cr montmorillonites produced by modifying the original montmorillonite sample. The evaluation and quantification of biodegradation and adsorption were carried out using a combination of the Iatroscan and gravimetric analysis. The SARA compositions in the presence of organomontmorillonite and acid-activated montmorillonite after incubation follow the same pattern in which the aromatic fraction is higher than the other fractions unlike in the presence of unmodified, K, Ca and Zn montmorillonites, where the saturates fraction is higher than the other fractions. Changes in SARA fractions due to biodegradation seemed to occur most in the presence of unmodified and calcium montmorillonites; hence, the removal of SARA fractions due to biodegradation was significant and enhanced in the presence of these two clay samples. However, biodegradation in the presence of organomontmorillonite and acid-activated and Cr montmorillonites was hindered. The study indicated that Cr montmorillonite adsorbed resins most, whereas Zn and K montmorillonites adsorbed aromatics most after incubation. 相似文献
133.
Despite the fact that virtual environments are increasingly deployed to study the relation between urban planning, physical and social disorder, and fear of crime, their ecological validity for this type of research has not been established. This study compares the effects of similar signs of public disorder (litter, warning signs, cameras, signs of vandalism and car burglary) in an urban neighborhood and in its virtual counterpart on the subjective perception of safety and livability of the neighborhood. Participants made a walking tour through either the real or the virtual neighborhood, which was either in an orderly (baseline) state or adorned with numerous signs of public disorder. During their tour they reported the signs of disorder they noticed and the degree to which each of these affected their emotional state and feelings of personal safety. After finishing their tour they appraised the perceived safety and livability of the environment. Both in the real and in the simulated urban neighborhood, signs of disorder evoked associations with social disorder. In all conditions, neglected greenery was spontaneously reported as a sign of disorder. Disorder did not inspire concern for personal safety in reality and in the virtual environment with a realistic soundscape. However, in the absence of sound disorder compromised perceived personal safety in the virtual environment. Signs of disorder were associated with negative emotions more frequently in the virtual environment than in its real-world counterpart, particularly in the absence of sound. Also, signs of disorder degraded the perceived livability of the virtual, but not of the real neighborhood. Hence, it appears that people focus more on details in a virtual environment than in reality. We conclude that both a correction for this focusing effect and realistic soundscapes are required to make virtual environments an appropriate medium for both etiological (e.g. the effects of signs of disorder on fear of crime) and intervention (e.g. CPTED) research. 相似文献
134.
Concentrations of 86 congeners of polychlorinated biphenyls (PCBs) were determined for 25 adult female and 25 adult male burbot (Lota lota) from Lake Erie. Significant differences in mean proportions of total PCB concentration between males and females ages 14–17 were found for 26 congeners. Males generally had higher mean proportions of hexachloro congeners, whereas females had higher mean proportions of more highly chlorinated congeners. In contrast, only four congeners exhibited differences between males and females ages 6–13 in mean proportions of total PCB. Therefore, the sexual difference in PCB congener distribution widened for older burbot. Males ages 14–17 also had higher proportions of certain hexachloro congeners than the other three demographic groups (males ages 6–13, females ages 6–13, and females ages 14–17) we examined. The reverse was true for more highly chlorinated congeners. The results supported a previous hypothesis that older male burbot spent a substantial amount of time feeding in the vicinity of mouths of rivers with sediment contaminated with PCBs. However, additional studies are needed to clarify and corroborate this apparent “hot spot” effect, such as seasonal movements, spatial distributions, and diet of burbot; and PCB congener distributions of various species of prey fishes captured at various locations throughout the eastern basin of Lake Erie and at different locations in the contaminated rivers. 相似文献
135.
Two drinking water production plants located in North Italy, collecting water from the River Po (Plants 1 and 2) were chosen for this study. Water samples were collected before and after the disinfection process and at two points along the piping system. Water samples were concentrated by the solid-phase extraction system and injected intraperitoneally into specimens of Cyprinus carpio. The concentration of water samples was 3 l/equiv. In order to assess the effects of the water samples on carp liver, total glutathione and glutathione-dependent enzymes, such as glutathione S-transferase, glutathione peroxidase, glutathione reductase and glyoxalase I, were measured following this treatment for 6 days at two experimental times (3 and 6 days). Both water plant-treated carp showed a general increase of the enzymatic activities of glutathione S-transferase, and glutathione reductase which might be employed as potential biomarkers of oxidative stress induced by disinfected river water. Plant 1-treated carp showed higher glyoxalase I and glutathione levels and lower glutathione peroxidase activity. A depleted level of total glutathione and of glyoxalase I for specimens of water plant 2 (for both experimental times), without correlation with the distances in the pipeline, suggests that river plant water can also lead to potentially adverse effects on selected biochemical parameters in C. carpio. 相似文献
136.
The behaviour and fate of macronutrients and pollutants in sewage sludge applied to the land are affected by the chemical composition of the sludge organic matter, which in turn is influenced by both sewage source and by sewage treatment processes. In this study, (13)C nuclear magnetic resonance (NMR) spectroscopy was used to characterise the organic matter of sludges collected at three different points along the treatment stream of a municipal sewage works with a domestic catchment. Sludge at the first point, an undigested liquid (UL) sludge, had a substantially different composition to the anaerobically digested (AD) and dewatered sludge cake (DC) materials, which were similar to each other. In particular, the UL sludge contained more alkyl C than the AD or DC sludges. All three sludges were found to contain mobile alkyl C that is poorly observed using the cross polarisation (CP) technique, necessitating the use of the less sensitive, but more quantitatively reliable direct polarisation (DP) technique to obtain accurate distributions of C types. 相似文献
137.
Many diets employed in aquaculture are enriched with selenium to improve the diet quality and its conservation. The aim of the study was to investigate the effects of a diet enriched in selenium (1.21 mg kg(-1)) on the antioxidant response of Procambarus clarkii (Girard, 1852). Crayfish fed a diet with lower selenium content (0.30 mg kg(-1)) were the control. Selenium accumulation, enzymatic activities, and total glutathione were evaluated in hepatopancreas of adults of both sexes fed with both diets for 50 days at two experimental times (T(30), T(50) days). Treated females exhibited the highest selenium bioaccumulation during both experimental times, while treated males displayed the highest selenium concentration after 30 days, compared to control crayfish. A sex-related difference was found for the response of the analyzed enzymes in the selenium diet-treated specimens. In fact, superoxide dismutase, glutathione peroxidase and glyoxalase I activities in males were more sensitive compared with females, showing depleted activities in both experimental times. Catalase activity was induced in females (T(50)), while glutathione S-transferase activity was the highest in treated females and the lowest in treated males, compared with own controls. Only glutathione reductase activity and glutathione content showed the same trend in both sexes, which were both lowered in treated specimens, when compared with control crayfish. This result might be due to the effect of selenium toxicity on this freshwater species. Males and females of P. clarkii showed a different susceptibility to the prooxidant effects in a Se-enriched diet. 相似文献
138.
A slack heap in Saxony serves as an example for the model procedure of evaluation heterogeneous waste sites via sampling as well as statistical and geostatistical data analysis. This paper demonstrates the usefulness of the known regulations for sampling and of the tried and proven geostatistical methods developed for assessing homogeneous wastes and the concornitantly contaminated soil. Emphasized here are the contents of iron and sulfur. Considered in addition are the concentrations of arsenic and the heat loss. To establish a conclusion, the variograms of the original data are used to evaluate the waste site in different directions and at determined depths. With the aid of a spot interpolation, further data can be calculated for additional sites which have not been sampled and can be used consequently for displaying the spatial variability. Finally, the statistical data analysis is applied using the standard methods of random sampling as an alternative to the geostatistical modeling. In this manner, the consequences for the sampling strategy can be demonstrated. 相似文献
139.
A stow net (90 m2 opening) was used, at regular intervals between July 1989 and June 1993, to collect fish over ca. 4 h on both the flood and
ebb tides at five sites distributed at regularly spaced distances throughout the Elbe Estuary. Overall, 53.4% of the species
were marine, and some of these were abundant, e.g.Clupea harengus, Pleuronectes flesus, Pomatoschistus minutus, Merlangius merlangus and Sprattus sprattus. However, in terms of number of individuals, such species contributed only 9.1%, compared with 90.0% by anadromous species,
which was predominantly due to exceptionally high catches of Osmerus eperlanus. The ichthyofaunal compositions on the flood and ebb tides were similar, even downstream where salinities change markedly
during each tidal cycle. Although this is probably due in part to groups of fish being swept first upstream on the flood tide
and then back downstream on the ebb tide, several species clearly tended to occupy particular regions of the estuary. Each
year the species composition changed sequentially from the most downstream site (max. salinity=ca. 31.4‰) to the most upstream
site (max. salinity=ca. 1.5‰), mainly as a result of a sequential decline in the number and abundance of marine species and
a progressive increase in the contributions of both anadromous and freshwater species. However, the marine species diagnostic
of differences in the compositions among regions varied between years. Thus, for example, the diagnostic species for the downstream
sites were C. harengus and M. merlangus in 1990/1991 and S. sprattus in 1992/1993, reflecting differences in the recruitment strengths of these marine species in the two years. The ichthyofaunal
composition exhibited pronounced annual cyclical changes in each region and thus occurred irrespective of whether or not the
salinity in a region underwent pronounced changes during the year. This cyclicity was attributable to intra-annual variations
in the times of recruitment of certain marine species, particularly in the downstream region, and to seasonal migrations of
diadromous species into each region, as well as to the movements of freshwater species into the upstream region in winter
and early spring.
Received: 18 November 1999 / Accepted: 25 October 2000 相似文献
140.
M. Thiel 《Marine Biology》1998,132(2):209-221
The suspension-feeding amphipod Dyopedos monacanthus (Metzger, 1875) is a common epibenthic amphipod that lives on self-constructed “mud whips” (built from filamentous algae,
detritus and sediment particles) in estuaries of the northern North Atlantic Ocean. The population biology of D. monacanthus at a shallow subtidal site in the Damariscotta River Estuary (Maine, USA) was examined between July 1995 and July 1997. The
resident population at the study site was dominated by adult females during most months of the year. High percentages of subadults
were found in late summer/early fall. Often, between 10 and 20% of the adult females were paired with males, and the percentage
of ovigerous females varied between 40 and 100%, indicating continuous reproduction. The percentage of parental females varied
between 40 and 80% during most months, but dropped to levels below 20% during summer/early fall. The average size of amphipods
on their own mud whips was ∼4 mm during the summer/early fall, after which it increased continuously to >7.0 mm in March or
April, and then dropped again. In March and April, the average number of eggs and juveniles female−1 was ∼100 eggs and 55 juveniles, while during the summer/early fall the average number of eggs female−1 was <20 and that of juveniles female−1 was <10. Many juveniles grew to large sizes (>1.4 mm) on their mothers' whips in winter/early spring but not in the summer/fall.
The average number of amphipods at the study site was low in late summer/early fall (<50 individuals m−2), increased steadily during the winter, and reached peak densities of >3000 individuals m−2 in April 1996 (>1600 individuals m−2 in May 1997), after which densities decreased again. The decrease of the D.␣monacanthus population at the study site coincided with a strong increase of amphipods found pelagic in the water column. This behavioural
shift occurred when temperatures increased and benthic predators became more abundant and active on shallow soft-bottoms,
suggesting that D. monacanthus at the study site is strongly affected by predation. The effects are direct (by predation on amphipods) and indirect (by
reducing duration of extended parental care and enhancing pelagic movements). Both extended parental care and pelagic movements
are important behavioural traits of D.␣monacanthus (and other marine amphipods), and significantly affect its population dynamics.
Received: 18 January 1998 / Accepted: 27 May 1998 相似文献