Male scent-marking pheromone of <Emphasis Type="Italic">Bombus ardens ardens</Emphasis> (Hymenoptera; Apidae) attracts both conspecific queens and males

To explore the role of the volatiles emitted from male labial gland (LG) of the bumblebee Bombus ardens ardens, we investigated the responses of virgin queens and males to volatiles using a gas chromatography–electroantennographic detector (GC–EAD) system and Y-tube olfactometer. GC–EAD analysis revealed that citronellol, the main compound detected in the male LG, caused clear electrophysiological responses in the antennae of B. a. ardens virgin queens and males although two minor compounds elicited antennal responses when applied in a high concentration. Behavioral tests using a Y-tube olfactometer showed that queens and males were significantly attracted to both LG extracts and citronellol more than to the solvent alone. This is the first study to demonstrate that citronellol as a major compound of male scent-marking pheromone in B. a. ardens functions as a sex attractant for queens. The results also suggest that this compound has another function as a trail marker used by males.     

Seasonality and microhabitat selection in a forest-dwelling salamander

Many small terrestrial vertebrates exhibit limited spatial movement and are considerably exposed to changes in local environmental variables. Among such vertebrates, amphibians at present experience a dramatic decline due to their limited resilience to environmental change. Since the local survival and abundance of amphibians is intrinsically related to the availability of shelters, conservation plans need to take microhabitat requirements into account. In order to gain insight into the terrestrial ecology of the spectacled salamander Salamandrina perspicillata and to identify appropriate forest management strategies, we investigated the salamander’s seasonal variability in habitat use of trees as shelters in relation to tree features (size, buttresses, basal holes) and environmental variables in a beech forest in Italy. We used the occupancy approach to assess tree suitability on a non-conventional spatial scale. Our approach provides fine-grained parameters of microhabitat suitability and elucidates many aspects of the salamander’s terrestrial ecology. Occupancy changed with the annual life cycle and was higher in autumn than in spring, when females were found closer to the stream in the study area. Salamanders showed a seasonal pattern regarding the trees they occupied and a clear preference for trees with a larger diameter and more burrows. With respect to forest management, we suggest maintaining a suitable number of trees with a trunk diameter exceeding 30 cm. A practice of selective logging along the banks of streams could help maintain an adequate quantity of the appropriate microhabitat. Furthermore, in areas with a presence of salamanders, a good forest management plan requires leaving an adequate buffer zone around streams, which should be wider in autumn than in spring.     

Postnatal nutrition influences male attractiveness and promotes plasticity in male mating preferences

Poor early-life nutrition could reduce adult reproductive success by negatively affecting traits linked to sexual attractiveness such as song complexity. If so, this might favor strategic mate choice, allowing males with less complex songs to tailor their mating tactics to maximize the reproductive benefits. However, this possibility has been ignored in theoretical and empirical studies. By manipulating the micronutrient content of the diet (e.g., low or high) during the postnatal period of male zebra finches, we show for the first time (1) that males reared on a poor (low) micronutrient diet had less complex songs as adults; (2) that these males, in contrast to the high micronutrient diet group, were more selective in their mating strategies, discriminating against those females most likely to reduce their clutch size when paired with males having less complex songs; and (3) that by following different mating strategies, males reared on the contrasting diets obtained similar reproductive benefits. These results suggest that early-life dietary conditions can induce multiple and long-lasting effects on male and female reproductive traits. Moreover, the results seem to reflect a previously unreported case of adaptive plasticity in mate choice in response to a nutritionally mediated reduction in sexual attractiveness.     

U and Th in some brown coals of Serbia and Montenegro and their environmental impact

GOAL, SCOPE AND BACKGROUND: The objective of this paper is to determine and compare the concentrations of U and Th in soft to hard brown (lignite to sub-bituminous) coals of Serbia and Montenegro. It also presents comparison of the obtained data on U and Th concentrations with the published data on coals located in some other countries of the world. Almost the whole coal production of Serbia and Montenegro is used as feed coals for combustion in thermal power plants. METHODS: Channel samples from open pit and underground mines and core samples were collected for hard and soft brown coals. For the analysis the samples were decomposed using microwave technique. Obtained solutions containing U and Th were analyzed by inductively coupled plasma mass spectroscopy (ICP-MS) using NIST standards. RESULTS: Concentration of U from the investigated basins and the corresponding mine fields ranges within 0.60-70.10 mg/kg, 0.65-3.20 mg/kg, 0.95-6.59 mg/kg, 1.20-6.05 mg/kg, 0.80-6.66 mg/kg, 0.18-89.90 mg/kg, 0.19-4.14 mg/kg, and 0.28-3.52 mg/kg for the Kostolac, Kolubara, Krepoljin, Sjenica, Soko Banja, Bogovina East field, Senje-Resavica and Pljevlja basins, respectively. Concentration of Th ranges within 0.20-2.60 mg/kg, 0.84-6.57 mg/kg, 1.48-6.48 mg/kg, 0.12-2.71 mg/kg, 0.13-4.95 mg/kg, 0.14-3.48 mg/kg, 0.29-3.56 mg/kg, and 0.17-1.89 mg/kg for the Kostolac, Kolubara, Krepoljin, Sjenica, Soko Banja, Bogovina East field, Senje-Resavica and Pljevlja basins, respectively. DISCUSSION: Brown coal from Senje-Resavica, Kolubara, Kostolac and Pljevlja is characterized by low U concentration. Coals form the Krepoljin, Soko Banja and Sjenica basins have slightly higher U concentrations than the mentioned group. The highest concentration of U is characteristic for the coal from the Bogovina East field. Concentration of Th in coals from Serbia and Montenegro has proved to be low. Out of all investigated coal basins, only the coal from the Krepoljin and Kolubara basins has high concentration of Th. The hydrothermally altered rocks of the Timok dacite-andesite complex, representing the basement of the Bogovina basin, could be a potential source of U, especially at the bottom part of the Lower seam of the Bogovina East field. CONCLUSIONS: This study shows that brown coals in Serbia and Montenegro (soft to hard brown coals or lignite to sub-bituminous) contain low levels of U (5.30 mg/kg, average value and 2.10 mg/kg geometric mean value) and Th (1.80 mg/kg, average value and 1.12 mg/kg geometric mean value). There are some obvious differences in concentration of U and Th in coals from different basins in Serbia and Montenegro. The approximate value for U and Th release mainly from power plants was 644.33 t and 983.46 t, respectively within the period 1965-2000 for the studied mines in Serbia, and 23.76 t and 15.05 t for the Potrlica mine (Montenegro) within the period 1965-1997. RECOMMENDATIONS: The coals in Serbia and Montenegro show no identifiable unfavourable impact on the surrounding environment, due to low natural radioactive concentration of U and Th, but further investigations concerning human health should be performed. PERSPECTIVES: Preliminary research revealed that in some Serbian coals (and, particularly, parts of the coal seam) U and Th content are rather high. Such coals should be carefully studied, as well as U and Th concentrations in ash, fly ash, waste disposals, nearby soil and ground water. Further studies should include determination of the radioactivity of all these products, and estimation of possible health impact.     

Effect of herbicides on glutathione S-transferases in the earthworm, <Emphasis Type="Italic">Eisenia fetida</Emphasis>

AIM AND BACKGROUND: Earthworms have been studied as a readily available, easily maintainable and cheap test species for assessing chemical pollution, and may be an alternative to in vivo rodent bioassays. The current investigation aims to characterize detoxification enzymes in Eisenia fetida and stress response against two herbicides with different modes of action, namely, fenoxaprop and metolachlor. METHODS: Herbicides were applied to soil containing earthworms. Animals were then collected, sacrificed and shock-frozen. Extracted protein was analyzed for glutathione S-transferase (GST) activity using CDNB (1-chloro-2,4-dinitrobenzene), DCNB (1,2-dichloro-4-nitrobenzene), pNBC (p-nitrobenzylchloride), PNOBC (p-nitrobenz-o-ylchloride) and selected herbicides. GST isoenzymes were partially purified by affinity chromatography and molecular weights were estimated by SDS-PAGE. RESULTS: In E. fetida protein extracts, GST activity towards model compounds ranked as CDNB>DCNB>PNBOC>PNBC. Fluorodifen was not conjugated at all, but fenoxaprop and metolachlor were conjugated at low rates. Furthermore, the GST isoenzyme pattern changed during the incubation with herbicides, either due to stress or as a defense reaction. After incubation with monochlorobimane, a strong fluorescence of the intestinal tract and the intersegments was observed, indicating organ-specific GST induction. DISCUSSION: According to the author's knowledge, here, for the first time, evidence is presented that E. fetida GST are also capable of conjugating a wider range of xenobiotic substrates. Different forms of GST were observed and changes in GST isoforms due to the herbicide treatment were also noticed. GST conjugation rates varied between different herbicides used in this experiment. It might be assumed that herbicides may well be detoxified by earthworms, to a certain extent, but that they are also potent stress factors influencing the detoxification system of the animal. High doses or long exposure might lead to deleterious effects on earthworms and limit their survival rate. The use of the animals as bioindicators for herbicides and herbicide residues seems very promising, but is surely influenced by the lack of detoxification for some compounds. CONCLUSIONS: Conjugation of several xenobiotics with model substances and herbicides is proven in the earthworm E. fetida. However, E. fetida has only limited capabilities of detoxifying herbicidal compounds. Different isoforms of GST were involved and altered in their activity after treatment. RECOMMENDATIONS AND PERSPECTIVES: The accumulation of GS-conjugates and their determination via fluorescence microscopy is a quick and secure, additional marker for exposure that should be further developed to complement existing biotests. The described methods and endpoints might help to understand the complex reaction of earthworms towards herbicides and lead to an adapted test methodology.     

Humic substances

GOAL, SCOPE AND BACKGROUND: Freshwater bodies which chemistry is dominated by dissolved humic substances (HS) seem to be the major type on Earth, due to huge non-calcareous geological formations in the Northern Hemisphere and in the tropics. Based on the paradigm of the inertness of being organic, direct interactions of dissolved HS with freshwater organisms are mostly neglected. However, dissolved organic carbon, the majority of which being HS, are natural environmental chemicals and should therefore directly interact with organisms. Major results that widened our perspective on humic substance ecology come from experiments with the compost nematode, Caenorhabditis elegans, which behaved contradictorily to textbook knowledge and provoked an in-depth re-consideration of some paradigms. APPROACH: To overcome old paradigms on HS and their potential interactions with organisms, we reviewed recent international literature, as well as 'grey' literature. We also include results from own ongoing studies. RESULTS: This review focuses on direct interactions of dissolved HS with freshwater organisms and disregards indirect effects, such as under-water light quenching. Instead we show with some macrophyte and algal species that HS adversely interfere with photosynthesis and growth, whereby closely related algal species show different response patterns. In addition to this, HS suppress cyanobacteria more than eukaryotic algae. Quinones in the HS appear to be the effective structure. Furthermore, HS can modulate the offspring numbers in the nematode C. elegans and cause feminization of fish and amphibians--they possess hormone-like properties. The ecological consequences of this potential remain obscure at present. HS also have the potential to act as chemical attractants as shown with C. elegans and exert a mild chemical stress upon aquatic organisms in many ways: induction of molecular chaperons (stress proteins), induction and modulation of biotransformation and anti-oxidant enzymes. Furthermore, they produce an oxidative stress with lipidperoxidation as one clear symptom or even stress defense strategy. Stronger chemical stresses by HS may even lead to teratogenic effects as shown with fish embryos; all physiological responses to HS-mediated stress require energy, which were compensated on the expense of yolk as shown with zebra fish embryos. One Finnish field survey supports the view of a strong chemical stress, as the weight yield in fish species decreases with increasing HS content in the lakes. DISCUSSION: HS exert a variety of stress symptoms in aquatic and compost organisms. According to current paradigms of ecotoxicology, these symptoms have to be considered adverse, because their compensation consumes energy which is deducted from the main metabolism. However, the nematode C. elegans looks actively for such stressful environments, and this behavior is only understandable in the light of new paradigms of aging mechanisms, particularly the Green Theory of Aging. In this respect, we discuss the mild HS-mediated stress to aquatic and compost organisms. New empirical findings with HS themselves and HS building blocks appear to be consistent with this emerging paradigm and show that the individual lifespan may be expanded. At present the ecological consequences of these findings remain obscure. However, a multiple-stress resistance may be acquired which improves the individual fitness in a fluctuating environment. CONCLUSIONS: It appears that dissolved HS have to be considered abiotic ecological driving forces, somewhat less obvious than temperature, nutrients, or light. PERSPECTIVES: The understanding of the ecological control by dissolved humic substances is still fragmentary and needs to be studied in more details.     

典型铬渣简易掩埋场铬渣及土壤铬污染特征和处置分析

通过钻孔采样分析,研究了典型铬渣简易掩埋场地下铬渣及土壤铬中Cr6 、总Cr的分布特征和污染状况,结果表明,铬渣简易掩埋场铬污染程度严重,引起了周边和地下深部较大面积的土壤污染,深度达到了地下的基岩.铬含量在土壤层剖面中分布呈现规律性变化,即随土壤深度增加,Cr6 、总Cr含量逐渐下降,但绝大多数超过了危险废物毒性鉴别标准.从铬污染程度上看,总体上存在铬渣>土壤>人工填土.在此基础上,提出了铬渣及污染土壤的处置方式,为铬渣污染治理和资源化利用提供科学依据.     

Diffusion pollution from livestock and poultry rearing in the Yangtze Delta,China

BACKGROUND: The Yangtze Delta is one of the most developed regions in China and includes Shanghai, eight cities in Jiangsu province and eight cities in Zhejiang province. Meat consumption in this region has increased with economic growth, and most of the consumed meat is produced locally. The water quality of surface waters has deteriorated in recent years. An example was the huge blue-green algae bloom in Tai Lake in late May 2007, which affected millions of people's daily drinking water. However, animal husbandry is considered to be one of the main pollution sources. METHODS: Pollutants (NH3-N, total phosphorus (TP), and total nitrogen (TN)) excreted by livestock and poultry, and the resultant COD (chemical oxygen demand) and BOD (biochemical oxygen demand), were estimated using two different methods based on different data sets. RESULTS: The number of livestock and poultry has remained stable in the Yangtze Delta over the four years from 1999 to 2002, with the average number of pigs, cattle, sheep and poultry being 21.1 M, 0.4 M, 7.7 M and 597.6 M, respectively. Pollutants in livestock and poultry excreta estimated by Method I were: 0.12 Mt NH3-N, 0.11 Mt TP and 0.29 Mt TN, resulting in COD and BOD of 1.34 Mt and 1.30 Mt, respectively, while the estimations based on Method II were: 0.18 Mt NH3-N, 0.15 Mt TP and 0.40 Mt TN, resulting in COD and BOD of 1.95 Mt and 1.80 Mt, respectively. DISCUSSION: Pollutants excreted annually by livestock and poultry in the Yangtze Delta are estimated to be: 0.17 Mt NH3-N, 0.16 Mt TP and 0.42 Mt TN, giving rise to a COD of 1.86 Mt and a BOD of 1.72 Mt. Approximately 25% of this pollution was estimated to enter water bodies, which means that the annual pollutant load is 43,700 t NH3-N, 39,400 tTP, 104,600t TN with a COD of 465,000 tand a BOD of 430,100 t. Pollutants from animal husbandry were similar in magnitude to those from industrial wastewater. Pigs produced the most pollution, followed by poultry, cattle and sheep. The pollution load from animal husbandry in the Yangtze Delta is about twice the average level of the whole of China. CONCLUSIONS: Domestic wastewater was the main pollution source in the Yangtze Delta, followed by pollution from raising livestock and poultry and from industrial wastewater. The pollution load in Shanghai and Jiaxing were the greatest, followed by 7 cities of Jiangsu province (except Suzhou) and other cities of Zhejiang province and Suzhou. Pigs and poultry produced about 90% of the total pollutants from animal husbandry. RECOMMENDATIONS AND PERSPECTIVES: The local governments, especially in Shanghai and Jiaxing, should focus their attention on the pollution produced by livestock and poulrry. Controlling pollution from pigs and poultry will have the greatest impact in this region. Control of pollution will be facilitated by the development of large-scale livestock and poultry farming units and a shift away from small scale husbandry.     

Dioxins,chlorophenols and other chlorinated organic pollutants in colloidal and water fractions of groundwater from a contaminated sawmill site

BACKGROUND, AIM, AND SCOPE: The distribution of chlorinated organic contaminants in groundwater and the importance of colloids were studied in groundwater from a sawmill site contaminated by chlorophenol preservatives. MATERIALS AND METHODS: The groundwater was fractionated into three different size ranges: (1) >0.7 mum, (2) 0.4-0.7 mum and (3) 0.2-0.4 mum and the filtered water phase. The concentrations of chlorophenols (CP), chlorinated phenoxy phenols (PCPP), chlorinated diphenyl ethers (PCDE), chlorinated dibenzofurans (PCDF) and chlorinated dibenzo-p-dioxins (PCDD) were determined in each fraction. The colloids were characterised regarding the chemical composition using X-ray photoelectron spectroscopy (XPS). RESULTS: Chlorophenols were mostly found in the water fraction and PCDD/Fs were found almost exclusively in the particulate fractions. For example, the filtered water phase contained 2,100 mug l(-1) and 0.72 ng l(-1) for CPs and PCDD/Fs, respectively, and the particulate fractions contained 27 mug l(-1) and 32 ng l(-1) for CPs and PCDD/Fs, respectively. XPS evaluation of the particulate phases showed no correlation between the surface chemistry of the particle properties and the distribution of chlorinated compounds. DISCUSSION: The results suggest that groundwater transport of CPs, PCPPs, PCDEs and PCDD/Fs may occur from contaminated sawmill sites and that the colloid-facilitated transport, especially of PCDD/Fs, is substantial. The results correlated well with previous studies of compounds sorbed to dissolved organic carbon, which indicate that dissolved and colloidal organic carbon facilitated the transport of PCDEs, PCDFs and PCDDs particularly. CONCLUSIONS: Several classes of chlorinated compounds were readily detected in the groundwater samples. Due to the differences in their physicochemical properties, CPs, PCPPs, PCDEs and PCDD/Fs vary in their partitioning between colloidal fractions and the filtered groundwater. The proportion of the bound fraction increased with an increasing hydrophobicity of the chlorinated compounds. The groundwater transport of colloid-associated pollutants from the site may be significant. RECOMMENDATIONS AND PERSPECTIVES: The results imply that colloidal particles <0.7 mum are freely mobile in groundwater from this site. The groundwater transport of colloid-associated pollutants may be significant. However, the extent of the problem is not yet known and, thus, further research is needed to evaluate the impact of colloidal transport of hydrophobic organic contaminants. In Sweden alone, 400 to 500 sawmill sites are estimated to be contaminated with PCDD/Fs as a result of the former use of CP-based wood preservatives. The widespread use of CP mixtures for a variety of applications, including wood preservation, indicates that potential colloidal transport will be an issue of concern in many countries.     

Characterization of the toxic effects of cadmium and 3.5-dichlorophenol on nitrifying activity and mortality in biologically activated sludge systems—effect of low temperature

Background, aims, and scope  Sometimes, urban wastewaters convey a more or less significant part of toxic products from industries or the craft industry. Nitrifying activity can be affected by these substances, implying higher ammonia concentrations in the outlet effluent and contributing to toxicity for the aquatic environment. Moreover, the more stringently treated wastewater standards now require a reliable treatment for nitrogen. One of the key issues is the identification of the inhibition behavior of nitrifying bacteria facing a toxic substance. This new understanding could then finally be integrated into models in order to represent and to optimize wastewater treatment plants (WWTP) operation in cases involving ‘toxic scenarios’. Materials and methods  The toxic substances studied in this work, cadmium and 3.5-dichlorophenol (3.5-DCP), are representative of chemical substances commonly found in municipal sewage and industrial effluents and symbolize two different contaminant groups. The effects of Cd and 3.5-DCP on nitrification kinetics have been investigated using respirometry techniques. Results  IC50 values determination gives concentrations of 3.1 mg/L for 3.5-DCP and 45.8 mg/L for Cd at 21 ± 1°C. The variation to low temperature seems to have no real effect on IC50 for DCP, but induces a decrease of cadmium IC50 to 27.5 mg/L at 14°C. Finally, specific respirometric tests have been carried out in order to determine the potential effect of these toxic substances on the nitrifying decay rate b _a . No significant effect has been noticed for Cd, whereas the presence of 3.5-DCP (at IC50 concentration) induced a dramatic increase of b _a at 20°C. The same behavior has been confirmed by experiments performed in winter periods with a sludge temperature around 12°C. Discussion  The target substances have different modes of action on activity and mortality, notably due to the abilities of the contaminant to be precipitated, accumulated, or even to be progressively degraded. Studies realized at low temperature confirmed this assumption, and put in evidence the effect of temperature on toxic substances capable of being biosorbed. However, the change in the sludge sample characteristics can be pointed out as a problem in the investigation of the temperature effect on nitrification inhibition, as biosorption, bioaccumulation, and predation are directly linked to the sludge characteristics (VSS concentration, temperature) and the plant operating conditions (loading rates, sludge age, etc.). Conclusions  This work brings new understandings concerning the action mode of these specific contaminants on nitrifying bacteria and, in particular, on the role of temperature. The experiments lead to the determination of the IC50 values for both toxic substances on biological nitrification. The inhibition mechanisms of Cd and 3.5-DCP on nitrifying activity have been simply represented by a non-competitive inhibition model. Recommendations and perspectives  Other experiments carried out in a continuous lab-scale pilot plant should be done with a proper control of the operating conditions and of the sludge characteristics in order to better understand the mechanisms of nitrification inhibition for each contaminant. Finally, these first results show that toxic substances can have an effect on the growth rate but also on the decay rate, depending on the characteristics of the toxic substance and the sludge. This eventual double effect would imply different strategies of WWTP operation according to the behavior of the contaminant on the bacteria.