Brominated flame retardants and related chlorinated persistent organic pollutants in fish from river Elbe and its main tributary Vltava

Brominated flame retardants (BFRs) are widely used industrial chemicals, residues of which can be nowadays found in all environmental compartments. The widespread presence of BFRs in various environmental compartments and food chain is a consequence of both their broad application area and physico-chemical properties, such as resistance to degradation and high lipophilicity. Alike in the case of other halogenated persistent organic pollutants (POPs), fish can be used as a bioindicator of aquatic environment pollution. In presented study, conducted in the year 2005, altogether 80 samples representing the most abundant fresh water fish species, viz. chub (Leuciscus cephalus), bream (Abramis brama), and perch (Perca fluviatilis) collected in 11 sampling sites located at Elbe and Vltava (Moldau) rivers were examined for levels of major BFRs. Without any exception, BFRs were detected in all fish samples. BDE 47 was the dominating congener in all fish species. This fact was not surprising, since it used to be the main component in various kinds of technical mixtures. With regard to relatively high levels of BDE 47 in fish tissue, as compared to other BFRs, and considering strong correlation with the total PBDEs content, simplified laboratory examination and, consequently, increased samples throughput can be obtained when only this congener is monitored. The potential of comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS), to provide more comprehensive information on the bioaccumulating chemicals occurring in fish samples, has been demonstrated in this study.     

Polymer selection for passive sampling: a comparison of critical properties

Next to the bi-phasic semipermeable membrane devices (SPMDs), single-phase passive samplers are becoming more popular for the sampling of hydrophobic contaminants. We therefore evaluated some critical properties of 13 polymers: low-density polyethylene (LDPE), polyoxymethylene (POM), silicone rubbers (SRs), including polydimethylsiloxane, and ethylene/octene co-polymer (EXACT). Polymer comparison included four critical properties: release of oligomers, swelling in solvents (dichloromethane, hexane, ethyl acetate, acetone and methanol), contaminant diffusion coefficients and partition coefficients for naphthalene, fluoranthene, benzo[a]pyrene and dibenz[a,h]anthracene. Amounts of extracted oligomers ranged from 2% to 4% for SRs and LDPE, to about 1% for EXACT. No oligomer release was observed for POM. Diffusion coefficients were higher in all SRs compared with LDPE and EXACT. No measurable diffusion was observed in POM after 24h of exposure. Differences in polymer-water partition coefficients spanned two orders of magnitude, with the lowest values observed for POM and the highest values observed for LDPE and EXACT. For the ten tested SRs, this range was less than 0.4 log units. Transport resistances estimated on the basis of diffusion coefficients and partition coefficients were generally lower for SRs than for LDPE and EXACT.     

Using historical ecology to reassess the conservation status of coniferous forests in Central Europe

Forests cover approximately one‐third of Central Europe. Oak (Quercus) and European beech (Fagus sylvatica) are considered the natural dominants at low and middle elevations, respectively. Many coniferous forests (especially of Picea abies) occur primarily at midelevations, but these are thought to have resulted from forestry plantations planted over the past 200 years. Nature conservation and forestry policy seek to promote broadleaved trees over conifers. However, there are discrepancies between conservation guidelines (included in Natura 2000) and historical and palaeoecological data with regard to the distribution of conifers. Our aim was to bring new evidence to the debate on the conservation of conifers versus broadleaved trees at midelevations in Central Europe. We created a vegetation and land‐cover model based on pollen data for a highland area of 11,300 km² in the Czech Republic and assessed tree species composition in the forests before the onset of modern forestry based on 18th‐century archival sources. Conifers dominated the study region throughout the entire Holocene (approximately 40–60% of the area). Broadleaved trees were present in a much smaller area than envisaged by current ideas of natural vegetation. Rather than casting doubt on the principles of Central European nature conservation in general, our results highlight the necessity of detailed regional investigations and the importance of historical data in challenging established notions on the natural distribution of tree species.     

Composition and effects of inhalable size fractions of atmospheric aerosols in the polluted atmosphere: Part I. PAHs,PCBs and OCPs and the matrix chemical composition

Atmospheric particulate matter (PM) abundance, mass size distribution (MSD) and chemical composition are parameters relevant for human health effects. The MSD and phase state of semivolatile organic pollutants were determined at various polluted sites in addition to the PM composition and MSD. The distribution pattern of pollutants varied from side to side in correspondence to main particle sources and PM composition. Levels of particle-associated polycyclic aromatic hydrocarbons (PAHs) were 1–30 ng m^?3 (corresponding to 15–35 % of the total, i.e., gas and particulate phase concentrations), of polychlorinated biphenyls (PCBs) were 2–11 pg m^?3 (4–26 % of the total) and of DDT compounds were 2–12 pg m^?3 (4–23 % of the total). The PM associated amounts of other organochlorine pesticides were too low for quantification. The organics were preferentially found associated with particles <0.45 μm of aerodynamic equivalent diameter. The mass fractions associated with sub-micrometer particles (PM_0.95) were 73–90 %, 34–71 % and 36–81 % for PAHs, PCBs and DDT compounds, respectively. The finest particles fraction had the highest aerosol surface concentration (6.3–29.7)_×10^?6 cm^?1 (44–70 % of the surface concentration of all size fractions). The data set was used to test gas-particle partitioning models for semivolatile organics for the first time in terms of the organics' MSD and size-dependent PM composition. The results of this study prove that at the various sites particles with diverse size, matrix composition, amount of contaminants and toxicological effects occur. Legislative regulation based on gravimetric determination of PM mass can clearly be insufficient for assessment.     

In situ cadmium reclamation by freshwater bivalve Lamellidens marginalis from an industrial pollutant-fed river canal

The biofilter potential of the freshwater bivalve, Lamellidens marginalis was examined in cage experiments conducted in a river canal (Ichhapore, 24-Parganas, West Bengal, India) receiving industrial effluents from steel and metal factories as well as from an ordinance factory. Cadmium is one of the major contaminants in this river canal. Lamellidens collected from pollution free natural ponds, were sorted into three size groups (large: 59+/-3.2 g, 10+/-2.3 cm; medium: 30+/-2 g, 6+/-1.7 cm and small: 13+/-1.5 g, 4+/-1.2 cm) were held in cages at three different sites along a cadmium concentration gradient. Concentrations of cadmium were measured from water, sediment and different tissues of Lamellidens at weekly intervals using atomic absorption spectrophotometric methods. Cadmium uptake by Lamellidens in all media were highly concentration dependent in both summer and winter months. For all three size groups, cadmium uptake was maximum in the gills at the beginning of experiment, and liver at the later phase. Cadmium uptake was maximum in the small bivalves and minimum in the large bivalves groups. Cadmium uptake was 11-67% higher during summer than during the monsoon season for all tissues and size groups. Estimation of concentration factor revealed that tissues were saturated with cadmium during the 13-14th week after Lamellidens introduction during summer, but remained unsaturated during the monsoon season. It is concluded that Lamellidens might be considered as an efficient biofilter for reclamation of aquatic environment having sub-lethal concentrations of cadmium.     

Influence of benomyl and prometryn on the soil microbial activities and community structures in pasture grasslands of Slovakia

The effects of pesticides (a herbicide and a fungicide) on the microbial community structure and their activity were analyzed in soil from four alpine pasture grasslands in Slovakia. Specifically, the effects of the herbicide, Gesagard (prometryn active ingredient), and fungicide, Fundazol 50 WP (benomyl active ingredient), on the microbial respiration activity (CO₂ production), the numbers of selective microbial physiological groups (CFU.g^?1) and the structure (relative abundance) of soil microbial communities [(phospholipid fatty acid (PLFA)] were analyzed under controlled laboratory conditions. All treatments including the treatments with pesticides increased (statistically significantly) the production of CO₂ in all fields during 21 days of incubation and posed a statistically insignificant negative influence on the numbers of the observed physiological groups of microorganisms. The significantly negative influence was evaluated only in the numbers of two physiological groups; spores of bacteria utilizing organic nitrogen and bacteria, and their spores utilizing inorganic nitrogen. A shift in the microbial composition was evident when the PLFA patterns of samples from different sites and treatments were compared by the Principal Component Analysis (PCA). According to the second component PCA 2 (15.95 %) the locations were grouped into two clusters. The first one involved the Donovaly and Dubakovo sites and the second one contained the Velka Fatra and Mala Fatra locations. The PLFA composition of the soils showed important changes after the treatment with pesticides according to PCA 1 (66.06 %). Other treatments had not had a significant effect on the soil microbial community with the exception of the population of fungi. The lower relative abundance (significant effect) of Gram-positive bacteria, actinomycetes and general group of bacteria were determined in samples treated by the herbicide Gesagard. The application of fungicide Fundazol decreased (statistically significantly) the relative abundance of actinomycetes and general group of bacteria and paradoxically increased the population of fungi.     

Influence of H2SO4 and ferric iron on Cd bioleaching from spent Ni–Cd batteries

The paper is concerned with biohydrometallurgical methods of cadmium recovery from spent Ni–Cd batteries. Cd leaching efficiency from electrode material in different media (H₂SO₄ and Fe₂(SO₄)₃ solutions), at different Fe(III) concentrations and using the bacteria Acidithiobacillus ferrooxidans were investigated. The main aim of this study was to understand which from the bioleaching products (sulphuric acid or ferric sulphate) play a main role in the bioleaching process of Cd recovery. The influence of Fe ions on Cd leachability was confirmed. The best leaching efficiency of Cd (100%) was reached by bioleaching and also by leaching in Fe₂(SO₄)₃ solution. The results of X-ray diffraction confirmed that no cadmium was present in solid residuum obtained after the Cd bioleaching as well as Cd leaching using solely ferric iron. The use of H₂SO₄ solution resulted in the lowest efficiency of Cd leachability, the presence of hydroxides in electrode materials caused neutralization of the leaching solution and inhibition of Cd leaching.     

Impact of market constraints on the development of small-scale biogas technology in Sub-Saharan Africa: a systematic review

The sustainable production and use of small-scale biogas energy are required to ensure clean household energy access in developing countries, including the Sub-Saharan Africa (SSA) region. This is influenced by market risks, which can be identified as political, economic, social, technical, legal, and environmental (PESTLE). This study examines peer-reviewed and grey literature for the period from 2000 to 2020 to identify the PESTLE constraints and assess their impact on the sustainable development of the technology in the SSA region. The production of biogas with small-scale plants is commonly done by rural and peri-urban households. Results show that economic constraints are the most dominant and reducing at a slow pace. This is followed by political constraints, which have received much attention in the last two decades. Despite the policy improvements, broader national bioenergy policies and interventions are still to make significant gains, especially in the Central African region. In order of significance, the Southern, East, and West Africa regions have made greater progress in reducing the constraints. To achieve the sustainable development of the technology, there is a need to further address the PESTLE constraints at national and regional levels. This study partly deduces that the unsustainable production, use, and inadequate regulation of the small-scale biogas sector are delaying its transition in the SSA region.