Biological effect monitoring in dab (<Emphasis Type="Italic">Limanda limanda</Emphasis>) using gene transcript of CYP1A1 or EROD—a comparison

BACKGROUND, AIM, AND SCOPE: Gene expression analyses with real-time (RT)-polymerase chain reaction (PCR) gains importance in marine monitoring. This new technique has to be compared to the classical approaches like the well known biomarker ethoxyresorufin-O-deethylase (EROD) to test their suitability for monitoring programmes. The goal of the present study is to compare EROD activity and CYP1A1 mRNA expression in the important monitoring fish species dab (Limanda limanda) and to answer the question of whether these parameters reflect the polycyclic aromatic hydrocarbon (PAH) contamination of the fish. Further on, glyceraldehyd-3-phosphate dehydrogenase (GAPDH) was investigated as a potential housekeeping gene. MATERIALS AND METHODS: Female dab were caught in the summer of 2004 in the North Sea and in the Baltic. EROD activity was determined in liver samples by a kinetic fluorimetric assay according to a standard protocol. The gene expression of CYP1A (cytochrome P450 1A) and GAPDH were determined by means of RT-PCR. Results were compared to gonado somatic index and to the concentration of PAH metabolite 1OHPyr (1-hydroxypyrene) analysed in the bile fluids of the fish, respectively. RESULTS: Dab from all stations showed a considerable individual variation in the levels of both CYP1A mRNA and EROD. Highest mean values for CYP1A mRNA and EROD were detected in the northern part of the sampling area. In contrast, the PAH metabolite 1OHPyr was found at the highest concentration in fish caught near the German coast. CYP1A mRNA and EROD showed only a minor but significant correlation (r = 0.32, p < 0.05, n = 123). 1OHPyr in bile correlated significantly (p < 0.05) with the amount of GAPDH mRNA content in the liver. DISCUSSION: The significant but low correlation of CYP1A mRNA and EROD activity on an individual basis illustrates that these two parameters are apparently not closely linked. However, maximum EROD values correspond with maximum CYP1A mRNA concentrations when station means are regarded. Because EROD and CYP1A mRNA in dab follow different physiological principles, their application will lead to related but not identical monitoring results. This should be taken into account when future marine monitoring programmes are designed. The results also indicate that PAH are not the crucial factor for CYP1A and EROD levels in dab from the off-shore areas in the North Sea. This is remarkable because the PAH metabolism is known to be CYP1A-dependent and the widely used biomarker EROD has been recommended for monitoring PAH-related effects in fish from the North Sea. Due to a correlation between GAPDH and 1OHPyr, GAPDH was not suitable as housekeeping gene for dab. CONCLUSIONS: Neither the results from EROD nor from CYP1A1 mRNA measurements in dab reflected their exposure to PAH as measured by the PAH metabolite 1OHPyr. Thus, the question arises of whether EROD or CYP1A mRNA is a suitable biomarker at all to indicate PAH exposure in dab from the open North Sea. RECOMMENDATIONS AND PERSPECTIVES: For future biological effect monitoring, it is advisable to measure more and predominately independent parameters by RT-PCR and to incorporate more components of the detoxification system.     

The historical record of PCB and PCDD/F deposition at Greifensee, a lake of the Swiss plateau, between 1848 and 1999

Dated sediment cores provide an excellent way to investigate the historical input of persistent organic pollutants into the environment and to identify possible sources of pollution. The vertical distribution of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/F) and polychlorinated biphenyls (PCB) was investigated in a sediment core from Greifensee to elucidate the historical trends of PCDD/F and PCB inputs between 1848 and 1999. Concentrations of PCB and PCDD/F increased by more than one order of magnitude between 1930 and 1960. PCB and PCDD/F concentrations were 5700 ng/kg dry weight (dw) and 160 ng/kg dw, respectively, in sediments originating from the late 1930s and reached a maximum of 130,000 ng/kg dw and 2400 ng/kg dw, respectively, in the early 1960s. From 1960 on, concentrations decreased to the 1930s level by the mid 1980s. A remarkable shift in the PCDD/F pattern was observed after the early 1940s. Before 1940, the PCDD/F pattern was PCDF dominated (ratio of PCDD to PCDF=0.41+/-0.11), while the PCDD started to be the major species after the early 1940s (ratio of PCDD to PCDF=1.46+/-0.38). The temporal trends of PCB and PCDD/F correlate surprisingly well with each other. This might be due to the coincidence of two factors. The introduction of PCB on the market in the 1930s resulted in emissions due to the widespread use of these industrial chemicals. In the same time period, waste incineration became an increasingly popular way to get rid of garbage, boosting the PCDD/F emissions significantly. The rapid decline of PCDD/F and PCB concentrations in the sediment starting in the early 1960s reflects the result of better emission control techniques in thermal processes and the improvement of waste water treatment in the catchment of Greifensee.     

Daytime resolved analysis of polycyclic aromatic hydrocarbons in urban aerosol samples - impact of sources and meteorological conditions

Urban aerosol was collected in a summer and a winter campaign for 7 and 3 days, respectively. Low volume samples were taken with a time resolution of 160 min using a filter/sorption cartridge system extended by an ozone scrubber. Concentrations of mainly particle associated polycyclic aromatic hydrocarbons (PAH) and oxidised PAH (O-PAH) were determined by gas chromatography/high resolution mass spectrometry. The sampling site was located in the city centre of Augsburg, Germany, near major roads with high traffic volume. The daily concentrations and profiles were mainly governed by local emissions from traffic and domestic heating, as well as by the meteorological conditions. During the winter campaign, concentrations were more than 10 fold higher than during the summer campaign. Highest concentrations were found concurrent with low boundary layer heights and low wind speeds. Significant diurnal variation of the PAH profiles was observed. Enhanced influences of traffic related PAH on the PAH profiles were evident during daytime in summer, whereas emissions from hot water generation and domestic heating were obvious during the night time of both seasons. A general idea about the global meteorological situation was acquired using back trajectory calculations (NOAA ARL HYSPLIT4). Due to high local emissions in combination with low air exchange during the two sampling campaigns, effects of mesoscale transport were not clearly observable.     

Risk assessment of linear alkylbenzene sulphonates, LAS, in agricultural soil revisited: robust chronic toxicity tests for Folsomia candida (Collembola), Aporrectodea caliginosa (Oligochaeta) and Enchytraeus crypticus (Enchytraeidae)

To obtain robust data on the toxicity of LAS, tests with the collembolan Folsomia candida L., the oligochaetes Aporrectodea caliginosa Savigny (earthworm) and Enchytraeus crypticus Westheide and Graefe (enchytraeid) were performed in a sandy loam soil. Additionally limited tests with LAS spiked to sewage sludge, and subsequently mixed into soil, were performed. For the endpoint of interest, reproduction in soil, we found an EC10 of 205 mg LAS kg(-1) soil [8.6-401] [95% confidence limits] for F. candida and an EC10 of 46 mg LAS kg(-1) soil [13-80] for A. caliginosa after 28 days. E. crypticus was not affected by concentrations up to 120 mg LAS kg(-1) soil. When adding (low contaminated) non-spiked sludge to soil, high stimulation of reproduction was observed for E. crypticus and A. caliginosa but not for F. candida. We argue that this difference in stimulative response between the tested species is related to the difference in feeding behaviour. Sludge spiked with LAS did not significantly affect the reproduction of F. candida (fertility: number of juvenile offspring) and A. caliginosa (fecundity: number of cocoons) (dose equivalent to 181 g and 91 g LAS kg(-1) sludge, respectively). Significantly reduced reproduction was observed for E. crypticus (at 120 mg LAS kg(-1) soil+sludge corresponding to 72 g LAS kg(-1) sludge) compared to non-spiked sludge. The reproduction by E. crypticus was, however, comparable to the reproduction observed in the control soil without sludge. Compared to LAS directly spiked to soil, the reproductive output of organisms exposed to spiked sludge was either not significantly different (F. candida, E. crypticus) or significantly improved (A. caliginosa). More studies are needed in order to make firm conclusions on the potential effect of artificially contaminated sludge in soil systems.     

Source to sink tracking of selected human pharmaceuticals from two Oslo city hospitals and a wastewater treatment works

The occurrence of twenty pharmaceutical compounds was quantitatively determined in effluents from two major Oslo city hospitals, Rikshospitalet and Ullev?l, along with influent, sludge and final effluent from the city's VEAS wastewater treatment works (WTW). Composite hospital effluents were collected over a twelve week period and were showed to contain paracetamol, metoprolol, diclofenac, ibuprofen, 17beta-Estradiol, estriol, estrone, oxytetracycline, tetracycline, doxycycline, chlorotetracycline, demeclocycline, trimethoprim, ciprofloxacin, sulfamethoxazole, cyclophosphamide and ifosfamide. Three pharmaceuticals were not detected above the limit of detection; cefuroxime, 17alpha-ethinylestradiol and meclocycline. Composite influent, sludge and effluent samples were collected from VEAS WTW over a seven week period. The influent into VEAS WTW contained all of the same selected substances detected in the hospital effluents, except for oxytetracycline, chlorotetracycline, demeclocycline, cyclophosphamide and ifosfamide. The percentage of pharmaceuticals entering the works from the hospitals was <10% for all of the selected compounds. VEAS sludge samples contained a different profile of substances reflecting their physico-chemical properties. Hydrophobic antibiotics, such as oxytetracycline, tetracycline and ciprofloxacin, were detected in all of the collected sludge samples. Their absence in the collected influent samples suggests that they enter the works bound to effluent particles, with the dissolved fraction observed in the hospital effluents partitioning onto particulate matter within the sewerage network. The final effluent from VEAS WTW contained reduced concentrations of many pharmaceuticals, including paracetamol, ibuprofen and sulfamethoxazole. For other compounds, such as metoprolol, diclofenac and trimethoprim, there were often higher concentrations in the effluent than the influent. These effluent concentrations represent median inputs varying from low g day(-1) (e.g. paracetamol and ibuprofen) to nearly 200 g day(-1) (e.g. metoprolol and trimethoprim) into Oslofjord. A simple risk assessment showed that the antibiotic ciprofloxacin may at times pose an acute risk to the Oslofjord aquatic environment.     

Combined effect of copper and prolonged summer drought on soil microarthropods in the field

Soil microarthropods experience a large range of natural stressors in their natural environment, e.g. variations in temperature and soil moisture, but also anthropogenic stressors such as soil pollutants. In the present study the combined effect of drought stress and copper pollution on microarthropods was investigated in a field study. We hypothesised that microarthropods in copper polluted soil would be more susceptible to drought than animals in control soil. Surprisingly, the abundance of microarthropods in autumn was positively affected by summer drought and copper pollution did not influence the effect of drought in a negative way. The stimulation was mainly seen as an increase of Acari, but also groups of Collembola were positively affected. We suggest that the positive effect of the enforced summer drought could be due to a rapid recovery, which further is accelerated by an increase of food resources (microbes) which have not been utilized during the drought.     

Plasma concentration of organochlorine compounds is associated with age and not obesity

It has been suggested that obese individuals, because of an increased dilution space (body fat) for lipophilic organochlorines compounds, may have greater levels of toxic pollutants than lean sedentary individuals. It is important to further examine this possibility because of the potential contribution of organochlorine pesticides in the development of Parkinson's disease and other neurological diseases. The aim of this study was to further investigate the relationship between the magnitude of obesity and the plasma concentration of organochlorines for a wide range of BMI (with participants at steady state body weight). Fifty-three individuals were selected on the basis of their body mass index (BMI): lean controls (n=16; mean BMI 22.8+/-2.2 kg/m(2); mean age 38.8+/-9.4 years), obese individuals (n=19; mean BMI 33.4+/-3.0 kg/m(2); mean age 38.6+/-7.6 years) and morbidly obese individuals (n=18; mean BMI 49.3+/-6.5 kg/m(2); mean age 44.3+/-9.2 years). Blood samples were analyzed for organochlorine compounds. The relationship between the total plasma organochlorine concentration and BMI was tested using a multiple regression analysis. Age was included in the model. There was no relationship between the total plasma organochlorine concentration and BMI. Organochlorine concentrations, however, were correlated with age (BMI-adjusted R(2)=0.46; p<0.001). At steady state body weight, toxic pollutant concentrations are not associated to obesity but strongly correlate with age.     

Black Rats, Island Characteristics, and Colonial Nesting Birds in the Mediterranean: Consequences of an Ancient Introduction

Abstract: The devastation of island faunas by alien species has been instrumental in raising concerns about the global threat to biological diversity. Colonial nesting species, often restricted to islands, have been affected severely. Eradication of introduced species as a means to alleviate the problem is usually done with little or no understanding of the mechanisms governing interactions between introduced and native species. Such an understanding could help target management action. We analyzed how island area, rock substrate, bird species biology, and presence of an introduced species, the black rat (   Rattus rattus ), interact to explain the distribution and abundance of colonial nesting birds on a set of 72 islands from six archipelagos in the western Mediterranean. Rats were introduced to this region over 2000 years ago, and these communities have had time to reach an equilibrium. Using general linear models, we show that rats have affected species distributions more on the smaller islands and on islands with an acidic or neutral rock substrate; larger bird species are more resistant. On the smaller islands, where rat densities are highest, larger colonial birds are negatively affected. On larger islands, where rat densities are lower and fluctuate form year to year, larger colonial birds can maintain healthy populations despite the presence of rats. Although rats caused local extinction or reduction in bird abundance, the presence of islands varying in size and/or substrate allowed most archipelagos to retain their suite of colonial nesting bird species, despite a presumably reduced abundance for most species.     

Ecological effects of cultivation on the machair sand dune systems of the Outer Hebrides, Scotland

The machair sand dune systems of the Outer Hebrides of Scotland are a unique habitat, which is rare within both a global and European context. Unusually, the machair habitat also represents an agricultural resource that is very important to the Hebridean people, having been subject to both grazing and cultivation throughout the historical period. Following designation as an Environmentally Sensitive Area (ESA) in 1988, the machairs of South Uist have been studied with the aim of understanding the links between agricultural practice and their plant community and ecosystem dynamics. This research focused primarily on the effects of cultivation practices and their role in maintaining plant species richness and community and ecosystem stability. Within two carefully selected areas, the successional plant communities of machair at different stages of recovery following ploughing and cultivation of cereals and potato patches or ‘lazy beds’ were identified at both a macro- and micro-level. Investigations of the vegetation recovery processes on turves taken from newly ploughed land indicated that the initial stages of recolonization are characterized primarily by rapid vegetative reproduction and growth, although re-vegetation by seeds is also an important factor. The implications of these findings for the long-term management of machair plant communities are discussed and in particular the need to maintain old cultivation practices such as shallow ploughing. The need for more detailed research into both seed banks and seed rain and into processes of vegetative reproduction is stressed. Nomenclature: Clapham et al. (1981) and Stace (1991, 1997) for vascular plants; Hubbard (1984) for grasses; Pankhurst & Mullin (1991) for the regional flora; Dobson (1992) for lichens; Watson (1981) for mosses and liverworts.