Entry and toxicity of organic pesticides and copper in vineyard streams: Erosion rills jeopardise the efficiency of riparian buffer strips

The present study was performed to characterise in-stream pesticide exposure within the Palatinate vineyard region in south-west Germany, evaluate the influence of buffer strip widths and identify mitigation measures for the relevant entry pathways. In-stream water and sediment samples that were taken at nine sampling sites of different buffer widths following intense rainfall, and edge-of-field runoff that were sampled in erosion rills were analysed regarding 28 active ingredients of pesticides including copper. In-stream samples contained a mix of 8 ± 4 pesticide compounds, resulting in total pesticide concentrations of 1.4-8.9 μg l⁻¹ for water and 16-670 μg kg⁻¹ dw for sediment. Following an exceptional rainfall event with a previous 34-day drought period, pesticide concentrations reached 7.0-83.4 μg l⁻¹. Fungicides were the most important pesticides found and were significantly correlated with the pesticide application frequency and rate. The calculated toxicity values per sample (TU_max) indicated that both organic pesticides and copper concentrations likely cause ecotoxicological effects in the field. The buffer strip width was of little importance for pesticide in-stream concentrations because pesticide entry occurred mainly via the field path network and erosion rills. Pesticide in-stream concentrations were significantly and positively correlated with the concentrations detected in erosion rills (R² = 0.56). As possible risk mitigation measures, we suggest the implementation of grassed field paths and vegetated ditches or wetlands.     

Temporal variance of disturbance did not affect diversity and structure of a marine fouling community in north-eastern New Zealand

Natural heterogeneity in ecological parameters, like population abundance, is more widely recognized and investigated than variability in the processes that control these parameters. Experimental ecologists have focused mainly on the mean intensity of predictor variables and have largely ignored the potential to manipulate variances in processes, which can be considered explicitly in experimental designs to explore variation in causal mechanisms. In the present study, the effect of the temporal variance of disturbance on the diversity of marine assemblages was tested in a field experiment replicated at two sites on the northeast coast of New Zealand. Fouling communities grown on artificial settlement substrata experienced disturbance regimes that differed in their inherent levels of temporal variability and timing of disturbance events, while disturbance intensity was identical across all levels. Additionally, undisturbed assemblages were used as controls. After 150 days of experimental duration, the assemblages were then compared with regard to their species richness, abundance and structure. The disturbance effectively reduced the average total cover of the assemblages, but no consistent effect of variability in the disturbance regime on the assemblages was detected. The results of this study were corroborated by the outcomes from simultaneous replicate experiments carried out in each of eight different biogeographical regions around the world.     

Monitoring of waste deposit derived groundwater contamination with organic tracers

Specific anthropogenic substances derived from seepage and leakage water from a waste deposit landfill were analysed in groundwater and drainage effluents using gas chromatography-mass spectrometry (GC/MS). Here, we demonstrate the application of an organic marker approach to study lateral and vertical distribution of contamination as well as the long-term emission behaviour. Source-specific and environmentally-stable pesticides, plasticisers and pharmaceuticals, such as N,N-diethyl toluamide, N-butyl benzene sulfonamide, clofibric acid, mecoprop and bisphenol A, were quantitatively analysed. A distinct lateral expansion was detected. Although temporal variations were high, no significant trend was observed.     

Compositional Limitations in Poly–3–Hydroxyalkanoates Produced by Pseudomonas oleovorans

It is well known that Pseudomonas oleovorans can utilize sodium octanoate for both cell growth and the synthesis of polyhydroxyalkanoates (PHAs), but it can utilize sodium butyrate only for limited cell growth and not for the polyester formation when this substrate is the sole carbon source. Therefore, these two substrates were evaluated as cofeeds for the possible incorporation of 3-hydroxybutyryl groups in the resulting PHA. When sodium butyrate and sodium octanoate were fed to P. oleovorans as cosubstrates in various proportions, the resultant cell density and polymer content were proportional to the amount of sodium octanoate in the feed. The PHA extracted from cells grown in all combinations of these cosubstrates had similar unit compositions of approximately 8 mole % 3-hydroxyhexanoate, 91 mole % 3-hydroxyoctanoate and 1 mole % 3-hydroxydecanoate. 3-Hydroxybutyrate units were not detected in any of the PHAs isolated, indicating that these units could not be incorporated in the copolymer synthesized by P. oleovorans either because the cell did not synthesize that monomer or, if it did, the PHA synthase could not copolymerize it with the longer chain monomers.     

Synthesis, Characterization, and Hydrolytic Degradation of Copolymers of 2-Methylene-1,3-dioxepane with Ethylene and with Styrene

2-Methylene-1,3-dioxepane (MDP) was copolymerized with ethylene (E) at a pressure of approximately 1000 psi and a temperature of approximately 70°C with AIBN as the free radical initiator. The copolymers obtained, poly(MDP-co-E), were characterized by elemental analysis, IR, ¹H-NMR and ¹³C-NMR spectroscopy, DSC, and GPC. The copolymers contained 2–15 mol% ester units. MDP was also copolymerized with styrene (S) at 120°C with di-t-butyl peroxide as the initiator to prepare the copolymer, poly(MDP-co-S). The number-average molecular weights of both types of copolymers were in the range of 6000 to 11,000, and the weight-average molecular weights were in the range of 9000 to 17,000. The melting temperatures of poly(MDP-co-E) decreased with increasing ester unit content in the copolymer. For the MDP-S copolymers, the glass transition temperatures decreased with increasing ester unit content. Both poly(MDP-co-E) and poly(MDP-co-S) were degraded by methanolysis, and their molecular weights decreased by the expected amounts based on the ester unit content.     

Levels and pattern of volatile organic nitrates and halocarbons in the air at Neumayer Station (70 degrees S), Antarctic

Levels and patterns of C1-C4/C9 organic nitrates were measured for the first time in Antarctica. The sampling was done by adsorptive enrichment on Tenax TA followed by thermodesorption cold-trap high resolution capillary gas chromatography with electron capture detection. 2-70 1 air on-column have been analyzed this way. C1-C9 alkyl mononitrates, C2-C4 alkyl dinitrates, C2-C4 hydroxy alkyl nitrates, and halocarbons could be identified in air samples collected near the German Neumayer Research Station, Antarctica, in February 1999. Volatile biogenic and anthropogenic halocarbons were used to assess the origin of the air parcels analyzed. The average concentration measured for sigmaC2-C6 alkyl nitrates was in the range of 9.2 +/- 1.8 ppt(v), while the sum of the mixing ratios of six C2-C4 hydroxy alkyl nitrates was in the range of 1.1 +/- 0.2 ppt(v). Moreover, C2-C4 alkyl dinitrates were found at levels near the detection limit of 0.1-0.5 ppt(v). The concentrations of organic nitrates found in Antarctic air represent ultimate baseline levels due to chemical and physical loss processes during long-range transport in the air. The South Atlantic and the Antarctic Ocean as a general secondary source for organic nitrates in terms of an air/sea exchange equilibrium has to be evaluated yet, but it seems logical. Our results confirm the common assumption that there are no biogenic marine sources of C2-C9 organonitrates. We have found a level of > 80 ppt(v) for methyl nitrate. This level if it can be confirmed in a systematic survey requires a strong biogenic source of methyl nitrate in the Antarctic Ocean.     

(M)VOC and composting facilities. Part 2: (M)VOC dispersal in the environment

BACKGROUND, AIMS AND SCOPE: Composting facilities are known to release odorous volatiles due to biodegradation of municipal waste and plant residues. Although odour perception and its grading is influenced by experience, attitude and adaptation, these emissions have created a lack of acceptance for residents in the vicinity of composting facilities. Enclosure of compost pile halls, ventilation systems and biofilters are often insufficient to minimise the burden of compost-derived compounds in the air. Moreover, economic considerations forced smaller communities to establish less sophisticated facilities with open storage areas and other relevant sources for wind-borne dispersal of bioaerosols. Aim of the present study was to characterise the immission and dispersal of microbial volatiles (MVOC) and, besides, to find coincidences between MVOC and compost odour. METHODS: In the course of this study, the surroundings of two composting facilities, differing in their type of process engineering, were investigated for emission of volatiles in the environment. Both microbially and plant-derived substances were assessed, several of which have low odour thresholds. Air samples were taken in distances ranging from 50 to 800 m in a downwind direction from each facility. RESULTS AND DISCUSSION: Compost-derived and microbial volatile organic compounds (MVOC) were found at distances of up to 800 m from the composting facilities. Terpenes like alpha-pinene, camphene and camphor were the dominant compounds and coincided with typical compost odour, whereas several typical MVOC were not found at greater distances. The terpenes in combination with certain MVOC may play an important role in the perception of compost odour. Exposure concentrations were not of toxicological relevance, but sensory irritation and psychohygienic effects due to an annoyance potential of such compounds should not be dismissed. RECOMMENDATIONS AND OUTLOOK: Although terpenes are generally associated with pleasant odour characteristics, they seemed to contribute to malodours in a mixture with other VOC, in this context of volatile waste from compost facilities. Malodorous emissions from biowaste have to be considered as sources of health complaints and the investigation of mixtures of compost-derived volatiles is still inevitable. Exposure levels have to be discussed taking VOC mixtures into account. Within composting facilities, technical devices have to be improved to minimise dispersal of volatiles to prevent residents from immissions eventually causing health complaints.