Bisphenol A induces yolk-sac oedema and other adverse effects in landlocked salmon (Salmo salar m. sebago) yolk-sac fry

Accumulation and toxicity of waterborne bisphenol A were studied in landlocked salmon (Salmo salar m. sebago) yolk-sac fry. In a short-term (96 h) exposure to five bisphenol A concentrations yolk-sac fry had higher accumulation rates and bioconcentration factors (BCF96) than earlier studies have shown for salmon eggs. Furthermore, the conditional uptake rate constant tended to decrease as exposure concentration increased. Fry were also exposed to bisphenol A for 42 days at three concentrations (10, 100 and 1000 microg/l), and changes in behaviour, morphology and histological structure were observed. After 6 days of exposure, the highest concentration (1000 microg/l) of bisphenol A caused fluid accumulation (oedema) in the yolk sac and haemorrhages in the front part of the yolk sac and in the head around the gill arches. Later on, the fry at 1000 microg/l showed phlegmatic behaviour and had darker skin coloration than the fry in the other treatments. At the two highest concentrations (100 and 1000 microg/l) histological changes were seen in liver cell nuclei, where strongly stained fragments were observed. In the control fry and the fry exposed to 10 microg/l the nucleolus was clearly visible and spherical in shape and no strongly stained fragments were present. This study shows that high concentrations of bisphenol A may have both morphological and histological effects on salmon yolk-sac fry.     

90Sr, 238U, 234U, 137Cs, 40K and 239/240Pu in Emmental type cheese produced in different regions of Western Europe

A method is presented for the determination of (90)Sr and uranium in Emmental type cheese collected in dairy plants from different European countries. Results display a significant correlation (r = 0.708 Student t-test = 6.02) between the (90)Sr content of the cheese and the altitude of grazing. The highest (90)Sr activity is 1.13 Bq kg(-1) of cheese and the lowest is 0.29 Bq kg(-1). Uranium activity is very low with a highest (238)U value of 27 mBq kg(-1). In addition, (234)U/(238)U ratio shows a large enrichment in (234)U for every location. Without any significant indication of the geographic origin of the cheese, this enrichment is believed to be due to the geological features of the pasture, soil and underground water. These results tend to prove that the contamination of milk by uranium originates principally from the water that the cows drink instead of the forage. This finding may have a great importance in models dealing with dairy food contamination by radionuclides following a nuclear accident. Also, the (90)Sr content and to a lesser extent the (234)U/(238)U ratio could be used to trace the authenticity of the origin of the cheese. (137)Cs activity is lower than the detection limit of 0.1 Bq kg(-1) in all the samples collected (n = 20). Based on natural (40)K activity in cheese (15-21 Bq kg(-1)), the decontamination factor for the alkaline cations from milk to cheese is about 20. Plutonium activity stays below the detection limit of 0.3 mBq kg(-1).     

Species richness and stand stability in conifer forests of the Sierra Nevada

Theoretical and empirical studies have long suggested that stability and complexity are intimately related, but evidence from long-lived systems at large scales is lacking. Stability can either be driven by complex species interactions, or it can be driven by the presence/absence and abundance of a species best able to perform a specific ecosystem function. We use 64 years of stand productivity measures in forest systems composed of four dominant conifer tree species to contrast the effect of species richness and abundance on three stability measures. To perform this contrast, we measured the annual growth increments of > 900 trees in mixed and pure forest stands to test three hypotheses: increased species richness will (1) decrease stand variance, (2) increase stand resistance to drought events, and (3) increase stand resilience to drought events. In each case, the alternate hypothesis was that species richness had no effect, but that species composition and abundance within a stand drove variance, resistance, and resilience. In pure stands, the four species demonstrated significant differences in productivity, and in their resistance and resilience to drought events. The two pine species were the most drought resistant and resilient, whereas mountain hemlock was the least resistant and resilient, and red fir was intermediate. For community measures we found a moderately significant (P = 0.08) increase in the community coefficient of variation and a significant (P = 0.03) increase in resilience with increased species richness, but no significant relationship between species richness and community resistance, though the variance in community resistance to drought decreased with species richness. Community resistance to drought was significantly (P = 0.001) correlated to the relative abundance of lodgepole pine, the most resistant species. We propose that resistance is driven by competition for a single limiting resource, with negative diversity effects. In contrast resilience measures the capacity of communities to partition resources in the absence of a single limiting resource, demonstrating positive diversity effects.     

Trophic transfer of pyrene metabolites and nonextractable fraction from Oligochaete (Lumbriculus variegatus) to juvenile brown trout (Salmo trutta)

Cell lines of Etroplus suratensis established in our laboratory were evaluated for their potential use as screening tools for the ecotoxicological assessment of tannery effluent. The cytotoxic effect of tannery effluent in three cell lines derived from eye, kidney and gill tissue of E. suratensis was assessed using multiple endpoints such as Neutral Red (NR) assay, Coomassie Blue (CB) protein assay and Alamar Blue (AB) assay. Acute toxicity tests on fish were conducted by exposing E. suratensis for 96 h to tannery effluent under static conditions. The toxic effect of tannery effluent on the survival of fish was found to be concentration and time dependent. The tannery effluent at the concentration of 15% caused 100% mortality at 96 h whereas the lower concentration (0.5%) caused 13.33% mortality. The cytotoxicity of tannery effluent was found to be similar in the three cell lines tested, independent of the toxic endpoints employed. EC₅₀ values, the effective concentration of tannery effluent resulting in 50% inhibition of cytotoxicity parameters after 48 h exposure to tannery effluent were calculated for eye, kidney and gill cell lines using NR uptake, AB and cell protein assays. Statistical analysis revealed good correlation with r² = 0.95-0.99 for all combinations between endpoints employed. Linear correlations between each in vitro EC₅₀ and the in vivo LC₅₀ data, were highly significant p < 0.001 with r² = 0.977, 0.968 and 0.906 for AB₅₀, NR₅₀, and CB₅₀, respectively.     

Fractionation and mobility of cadmium and zinc in urban vegetable gardens of Kano, Northern Nigeria

Metal fractionation provides information on mobility and stability of various metal species which can be used to evaluate the movement of such metals in soils. The effect of wastewater irrigation on the fractions, spatial distribution, and mobility of cadmium (Cd) and zinc (Zn) was investigated in five urban gardens in Kano, Nigeria. Concentration of total Zn in the surface soils (0–20 cm) ranged from 121 to 207 mg kg^− 1 while Cd concentration was 0.3–2.0 mg kg^− 1. Speciation of both heavy metals into seven operationally defined fractions indicated that the most reactive forms extracted with ammonium nitrate and ammonium acetate, also considered as the bioavailable fractions, accounted for 29–42% of total Cd and 22–54% of total Zn, respectively. The weakly bound fractions of Cd and Zn reached up to 50% of the total Cd and Zn concentrations in the soils. Such high proportions of labile Cd and Zn fractions are indicative of anthropogenic origins, arising from the application of wastewater for irrigation and municipal biosolids for soil fertility improvement. Thus, given the predominance of sandy soil textures, high concentrations of labile Cd and Zn in these garden soils represent a potential hazard for the redistribution and translocation of these metals into the food chain and aquifer.     

Field uptake rates of hydrophobic organic contaminants by semipermeable membrane devices: environmental monitoring considerations

The uptake rates of selected hydrophobic organic contaminants (HOCs) by semipermeable membrane devices (SPMDs)--a polyethylene layflat containing the lipid triolein--were investigated under natural conditions. SPMDs were exposed in three sampling sites (industrial, urban, and agricultural areas) in the Tajo River (Toledo, Spain) for 5, 11 and 20 d. The organochlorine compounds 4,4'-DDT, 4,4'-DDE, alpha-HCH, gamma-HCH, pentachlorobenzene, hexachlorobenzene, and polychlorinated biphenyls (PCBs), and the 16 priority pollutant polycyclic aromatic hydrocarbons (PAHs) were detected in the SPMDs deployed in the three sampling sites. A linear uptake rate was found for DDTs and for 4-Cl- and 5-Cl-substituted PCB congeners in all sampling sites. Concentrations of HCHs (80.3 ng g(-1) SPMD for alpha-HCH and 109 ng g(-1) SPMD for gamma-HCH after 20 d of exposure) increased according to a linear uptake rate in the SPMDs deployed in the sampling site located in the agricultural area. Likewise, a marked increase of total PAH concentration (up to 300 ng g(-1) SPMD after 20 d of exposure) was solely found in the sampling site situated near a thermoelectric power station. Examination of individual PAHs revealed that PAHs with log K(OW) between 4.2 and 5.7 displayed a linear uptake rate over the 20 d of exposure. Water concentrations (ng L(-1)) of HCB (0.80-2.48), lindane (1.30-11.5), 4,4'-DDT (0.61-2.02), 4,4'-DDE (6.89-11.6) and total PAHs (12.0-26.7) estimated by a linear uptake kinetic model were found to be high in comparison with other polluted aquatic systems, and similar to concentrations in other Spanish rivers. Our results suggest that SPMD kinetic uptake studies in the natural environment are recommended for identifying point-pollution sources, and that shorter times of SPMD exposure (approximately 1 week) are desirable to minimize one of the main problems of field SPMD deployment, i.e., the biofouling, which negatively affects the estimation of the dissolved HOC concentrations.     

聚合物改性粉煤灰制备多孔复合材料及其性能研究

制备了高掺量粉煤灰为基质的聚乙烯醇/纤维素复合多孔材料。该复合材料制备过程简单易行,不需高温高压。通过XRF、XRD、FT-IR、SEM以及压汞法对该粉煤灰复合材料进行了表征和结构分析,探索了原料混合比例、干燥温度对样品结构和性能的影响。研究发现:聚乙烯醇可以有效提高该复合材料的无侧限抗压强度,纤维素可有效改善材料的孔隙结构;材料的孔隙主要来自水分蒸发过程中的气泡聚合,在外部不加压的条件下制备样品,需控制干燥温度对样品内部孔隙结构的影响。当粉煤灰含量为80%,聚乙烯醇含量为10%,纤维素含量为10%时,复合材料具有较好的孔隙率、孔隙结构、抗压强度和吸水性及保水性。有一定强度的以粉煤灰为基质的亲水性材料也适合作为吸附材料或滤料,未来可以进一步通过改善材料内部结构,以及活化功能性官能团以提高材料的综合性能,为粉煤灰的综合利用拓展途径。     

Air sampling of fungal spores on filters. An investigation on passive sampling and viability

In this study, glycerol was tested as a collection substrate for passive bioaerosol sampling. Filters (mixed cellulose acetate and nitrate) were soaked in glycerol and exposed for an aerosol from three different fungal species: Penicillum commune, Aspergillus versicolor and Paecilomyces variotii. The passive sampling method was compared with a closed-face polycarbonate filter sampling method. Exposure was performed in an exposure chamber. The total number of spores was determined by microscopic techniques, and the cultivable number was determined by cultivation on Malt Extract Agar dishes. The glycerol soaked filter demonstrated a good correlation with the closed-face sampler with regard to the total count. Spores stored in a pumped filter cassette were not affected by storage for up to 7 days. On the other hand, the culturability of the spores was markedly decreased after 1 day when stored on glycerol soaked filters.     

Polychlorinated biphenyls in farmed and wild <Emphasis Type="Italic">Onchorhynchus kisutch</Emphasis> and <Emphasis Type="Italic">Onchorhynchus mykiss</Emphasis> from the Chilean Patagonia

Purpose  

This paper analyses the presence of polychlorinated biphenyls (PCBs) in escaped: farmed and wild salmons in southern Chile, analysing their concentrations and congener profiles in two species (Oncorhynchus kisutch and Oncorhynchus mykiss).     

Trace element concentrations from lichen transplants in Pretoria,South Africa

Purpose  

The purpose of this study was to assess the level and possible sources of trace elements in Tshwane metropolis using transplanted lichen thallus of Parmelia sulcata with a view to evaluating the ability of this lichen species to monitor air pollutants from a perceived polluted environment.