Anaerobic Biodegradation of Polyvinyl Alcohol Modified by Extracellular Polysaccharides

This work focused on anaerobic biodegradation of blends composed of glycerol-plasticized polyvinyl alcohol (PVA) and biopolymer (starch, gellan, xanthan) in an aqueous environment, after inoculation with digested activated sludge from a municipal wastewater treatment plant. Glycerol degradability is comparable to degradability of used modifying agents. Modifying agents added in the 20–40 wt% range proportionally increased biodegradation degree (D_t) calculated from balance of transformed carbon in the system. Biodegradation degree of polysaccharides and glycerol attained 95% and over. For PVA it was only 6.5% (in breakdown times up to 500 h). Content of polysaccharides favorably affects biodegradation degree of polyvinyl alcohol blends, but at the expense of reduced mechanical properties of resultant products.     

Terrestrial Biodiversity Analyses in Dalmatia (Croatia): A Complementary Approach Using Diversity and Rarity

Here we present the methodology used for terrestrial biodiversity analysis and site selection in Phase B of the UNDP/GEF COAST project. The analysis was focused on the problem of biodiversity evaluation in four Croatian counties stretching from sea level to the highest mountain in Croatia. Data on habitats, vascular flora, and fauna (mammals, birds, reptiles, amphibians, butterflies, ground beetles, and underground invertebrates) were collected and analyzed for each of the four counties. Emphasis was given to the richness of endangered species and the rarity of endemic species. Based on the spatial analyses of habitat, fauna, and flora data, four to six areas were selected from each county and ranked according to their biodiversity importance. Overlap between areas important for richness and those important for rarity was highest for data on flora (65.5%) and lowest for data on fauna (16.7%). When different data sets were compared, the lowest overlap was between flora and fauna (17.1%) and largest between fauna and habitats (23.9%). Simultaneous overlap among all three data sets was found in just 6.5% of the overall selected areas. These results suggest that less specific data, with respect to taxa threat status, could better serve as surrogate data in estimating overall biodiversity. In summary, this analysis has demonstrated that Dalmatia is a region with a high overall biodiversity that is important in a broader European context.     

Recent changes (1973–2014 versus 1903–1972) in the flow regime of the Lower Paraná River and current fluvial pollution warnings in its Delta Biosphere Reserve

Alterations in flow regimes of large rivers may originate or increase risks to ecosystems and humans. The Paraná River basin (South America) undergoes human pressures (e.g., heavy damming in the upper basin, deforestation, and mixed pollution) that may affect the water quantity and quality of its terminal Delta (Argentina). In this study, after applying univariate and multivariate change-point detection and trend analyses to the daily data series of flows incoming to the Delta (Paraná-Santa Fe section), flow characteristics were compared by Indicators of Hydrologic Alteration (IHA) and Environmental Flow Components (EFC). Some flood characteristics were also compared from hydrometric levels in the middle Delta (San Pedro station). Chemical and microbiological water variables in the main rivers of the “Paraná Delta” Biosphere Reserve were examined during two extreme hydrologic years (October 2008 to July 2010) to detect potential risk factors in association with hydrologic conditions. In the Lower Paraná River, a historical period (1903–1972) and two more altered periods (1973–1999 wet period and 2000–2014 dry period) were identified. Flow duration curves evidenced different changes in both altered periods, reflecting the joint effect of climatic variability and human influence. The most evident alterations in the flow regime were the lack of record of the extreme-low-flow component, the attenuation of monthly flow seasonality, and the increase in the number of reversals (dry period) and in the variability of maximum and minimum flow dates. These alterations are consistent with the monthly and daily flow regulation by upstream dams evidenced by available data from the current dry period. In the middle Delta, the marked monthly seasonality in flood days decreased only in the wet period. The proportion between the number of flood days exceeding the evacuation level and that of those exceeding the warning level doubled in the wet period but decreased only slightly in the dry period. In the Delta Reserve rivers, concentrations of Escherichia coli, cadmium, lead, iron, manganese, and ammonium exceeded guideline levels under a severe drought and a dispersal of cyanobacteria appeared under a high-flow pulse in La Niña year. The ammonium concentration exceeded the level for human drink with the overbanking flood stage in El Niño year. These occasional detections pose a potential risk to the aquatic life and, especially, to the inhabitants of the Reserve. Flow duration curves, IHA, and EFC are useful tools to evaluate trends or changes of ecological and social relevance in flow regime characteristics.     

(210)Po and (210)Pb activity concentrations in Mytilus galloprovincialis from Croatian Adriatic coast with the related dose assessment to the coastal population

Activity concentrations of ²¹⁰Po and ²¹⁰Pb in the species Mytilus galloprovincialis from Croatian Adriatic coast were determined. The samples were collected in thirteen sampling places which are also a part of Croatian Mediterranean mussel watch project. The results of ²¹⁰Po and ²¹⁰Pb activity concentrations were found to vary between (22.1 ± 2.5)-(207 ± 21) Bq kg⁻¹ fresh weight and (2.8 ± 1.4)-(9.3 ± 0.7) Bq kg⁻¹ fresh weight, respectively. ²¹⁰Po/²¹⁰Pb ratio ranged between 6.2 and 30.7. The highest measured activities were found in the enclosed basins of the Neretva channel, where the majority of Croatian mussel cultivation is taking place. The estimated consequent average total annual effective ingestion dose due to ²¹⁰Po and ²¹⁰Pb from mussel consumption in Croatian coastal region is 202 ± 99 μSv with 96% contribution of ²¹⁰Po to the total effective dose.     

Evaluation of bendiocarb cytotoxicity in mammalian and insect cell cultures

There is an increasing need for rapid and easily interpreted in vitro assays to screen for possible cytotoxicity of pesticides. The objective of this study was to investigate the effect of the carbamate insecticide bendiocarb on mammalian and insect cell cultures. The cytotoxicity of this insecticide was evaluated by cell proliferation and cellular damage was assessed by evaluation of the cytopathic effect and lactate dehydrogenase (LDH) leakage. Cells of insect origin (Sf21) were the most sensitive to bendiocarb with significant (P < 0.01) suppression of their proliferative activity ranging from 10(-1)-10(-5) M. However, significant suppression of proliferative activity was also recorded in rat liver cells (WBF344; 10(-1)-10(-3) M; P < 0.01-0.05) and rabbit kidney cells (RK13; 10(-1) M; P < 0.01). In contrast with the proliferation activity of cells, a cytopathic effect based on cellular damage and LDH leakage into the medium was observed only at the highest concentration (10(-1) M) in RK 13 and WBF344 cells, but not in the Sf21 insect cell line. Our results indicate that bendiocarb exposure caused a cell-type dependent decrease in cell proliferation; however, cell damage and LDH leakage into the medium were not present or were strongly limited, dependent on the cell phenotype. Cell proliferation was shown as a sensitive indicator for evaluation of the cytotoxic effect of bendiocarb in vitro; on the other hand, microscopic signs of cellular damage and LDH leakage were insufficient in vitro markers.     

Uranium uptake by hydroponically cultivated crop plants

Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC₅₀ value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC₅₀ = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM.Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation.     

Levels of ²¹⁰Po and ²¹⁰Pb in fish and molluscs in Slovenia and the related dose assessment to the population

²¹⁰Po and ²¹⁰Pb activity concentrations in fish from the Slovenian part of Adriatic Sea, in the vicinity of a former uranium mine at ?irovski vrh and from the Slovenian market were determined. In addition, ²¹⁰Po and ²¹⁰Pb activity concentrations in squid from the Slovenian market and in mussels from the Slovenian part of the Adriatic Sea were also determined. Fish, squid and mussel consumption in Slovenia was assessed from the data available from Eurostat and Food and Agriculture Organisation (FAO) and the data used for the corresponding dose calculation. Fish species with the highest activity concentrations were grilled to assess possible loss of ²¹⁰Po during the food preparation process. Samples were freeze dried and radiochemical separation of ²¹⁰Po and ²¹⁰Pb was performed. Measurements of ²¹⁰Po were performed by alpha spectrometry and ²¹⁰Pb by a low background gas-flow proportional counter. ²¹⁰Po activity concentrations in fish, squid and mussels were from 0.039 to 35.0 Bq kg⁻¹ fresh weight and ²¹⁰Pb activity concentrations were from 0.08 to 3.03 Bq kg⁻¹ fresh weight. Grilling of fish resulted in no significant loss of ²¹⁰Po at 90 °C. The assessed combined annual effective ingestion dose due to ²¹⁰Po and ²¹⁰Pb for fish, squid and mussels consumed in Slovenia is 47.6 μSv year⁻¹.     

The toxicity of composted sediments from Mediterranean ports evaluated by several bioassays

This work investigates the ecotoxicological evaluation of contaminated dredged sediments from French Mediterranean navy harbour (A), commercial port (B) and two composite specimens (C) and (D) coming from the mixture of A and B with other port sediments. The toxicity of elutriates from these sediments is estimated using embryo-toxicity test, Microtox® solid phase test, LuminoTox, phytotoxicity tests and genotoxicity test. Bioassay responses are not clearly correlated with chemical contamination in the whole sediment and vary as a function of tested organisms. The highest contaminated samples (A and C) are almost always more toxic than the less contaminated samples (B and D). Among composite sediments, the mixture effect with other sediments is not efficient to decrease toxicity in sample C, suggesting that other parameters influence toxicity level such as particle size or organic matter content. These parameters should be taken into consideration in order to improve the efficiency of the mixture process and produce composite sediments with low toxicity.     

Accumulation of organochlorine contaminants in loggerhead sea turtles, Caretta caretta, from the eastern Adriatic Sea

We analyzed 15 polychlorinated biphenyls (PCBs) and five organochlorine pesticides (OCPs) in fat tissue of 27 loggerhead sea turtles (Caretta caretta) from eastern Adriatic Sea with the curved carapace length ranging from 25.0 to 84.5 cm. The PCB profile was dominated by hexa- and hepta-chlorinated congeners, with PCB-153 (median: 114.9 ng g⁻¹ wet mass), PCB-138 (80.0 ng g⁻¹ w.m.), and PCB-180 (26.7 ng g⁻¹ w.m.) detected with the highest levels. Toxic mono-ortho congeners PCB-118, PCB-105 and PCB-180 with dioxin-like toxicity were found in >70% samples. 4,4′-DDE (81.0 ng g⁻¹ w.m.) prevailed the OCP signature, accounting for 80% of the total DDTs. A significant increasing trend in accumulation with size was found for PCB-52 (r_s = 0.512, p < 0.01) and PCB-114 (r_s = 0.421, p < 0.05). Comparison of our results with organochlorine contaminant (OC) pattern in some prey taxa suggest that contamination occurs primarily through the food web, with biomagnification factors of 0.14-6.99 which were positively correlated with the octanol-water partition coefficient (log K_ow; p < 0.05). This study, based upon a fairly large sample size collected mostly from incidentally captured animals over a short time period (June 2001-November 2002), present a temporal snapshot of OC contamination in wild, free-ranging loggerheads from Adriatic feeding grounds and provide a baseline for monitoring the regional OC trends in this endangered species.     

Ex situ bioremediation of a soil contaminated by mazut (heavy residual fuel oil)--a field experiment

Mazut (heavy residual fuel oil)-polluted soil was exposed to bioremediation in an ex situ field-scale (600 m(3)) study. Re-inoculation was performed periodically with biomasses of microbial consortia isolated from the mazut-contaminated soil. Biostimulation was conducted by adding nutritional elements (N, P and K). The biopile (depth 0.4m) was comprised of mechanically mixed polluted soil with softwood sawdust and crude river sand. Aeration was improved by systematic mixing. The biopile was protected from direct external influences by a polyethylene cover. Part (10 m(3)) of the material prepared for bioremediation was set aside uninoculated, and maintained as an untreated control pile (CP). Biostimulation and re-inoculation with zymogenous microorganisms increased the number of hydrocarbon degraders after 50 d by more than 20 times in the treated soil. During the 5 months, the total petroleum hydrocarbon (TPH) content of the contaminated soil was reduced to 6% of the initial value, from 5.2 to 0.3 g kg(-1) dry matter, while TPH reduced to only 90% of the initial value in the CP. After 150 d there were 96%, 97% and 83% reductions for the aliphatic, aromatic, and nitrogen-sulphur-oxygen and asphaltene fractions, respectively. The isoprenoids, pristane and phytane, were more than 55% biodegraded, which indicated that they are not suitable biomarkers for following bioremediation. According to the available data, this is the first field-scale study of the bioremediation of mazut and mazut sediment-polluted soil, and the efficiency achieved was far above that described in the literature to date for heavy fuel oil.