Flame retardants, surfactants and organotins in sediment and mysid shrimp of the Scheldt estuary (The Netherlands)

Sediment and mysids from the Scheldt estuary, one of the largest and most polluted estuaries in Western Europe, were analyzed for a number of contaminants that have been shown to possess endocrine-disrupting activity, i.e. organotins, polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), nonylphenol ethoxylates (NPE) and transformation products, nonylphenol (NP) and nonylphenol ether carboxylates (NPEC). In addition, in vitro estrogenic and androgenic potencies of water and sediment extracts were determined. Total organotin concentrations ranged from 84 to 348 ng/g dw in sediment and 1110 to 1370 ng/g dw in mysid. Total PBDE (excluding BDE-209) concentrations ranged from 14 to 22 ng/g dw in sediment and from 1765 to 2962 ng/g lipid in mysid. High concentrations of BDE-209 (240-1650 ng/g dw) were detected in sediment and mysid (269-600 ng/g lipid). Total HBCD concentrations in sediment and mysid were 14-71 ng/g dw and 562-727 ng/g lipid, respectively. Total NPE concentrations in sediment were 1422 ng/g dw, 1222 ng/g dw for NP and 80 ng/g dw for NPEC and ranged from 430 to 1119 ng/g dw for total NPE and from 206 to 435 ng/g dw for NP in mysid. Significant estrogenic potency, as analyzed using the yeast estrogen assay, was detected in sediment and water samples from the Scheldt estuary, but no androgenic activity was found. This study is the first to report high levels of endocrine disruptors in estuarine mysids.     

Pyrolysis of virgin and waste polypropylene and its mixtures with waste polyethylene and polystyrene

A comparison of waste and virgin polypropylene (PP) plastics under slow pyrolysis conditions is presented. Moreover, mixtures of waste PP with wastes of polyethylene (PE) and polystyrene (PS) were pyrolyzed under the same operating conditions. Not only the impact of waste on degradation products but also impacts of the variations in the mixing ratio were investigated. The thermogravimetric weight loss curves and their derivatives of virgin and waste PP showed differences due to the impurities which are dirt and food residues. The liquid yield distribution concerning the aliphatic, mono-aromatic and poly-aromatic compounds varies as the ratio of PP waste increases in the waste plastic mixtures. In addition to this, the alkene/alkane ratio of gas products shows variations depending on the mixing ratio of wastes.     

Long-Term Effects of Logging on African Primate Communities: a 28-Year Comparison From Kibale National Park, Uganda

Abstract: If logging is to be compatible with primate conservation, primate populations must be expected to recover from the disturbance and eventually return to their former densities. Surveys conducted over 28 years were used to quantify the long-term effects of both low- and high-intensity selective logging on the density of the five common primates in Kibale National Park, Uganda. The most dramatic exception to the expectation that primate populations will recover following logging was that group densities of Cercopithecus mitis and C. ascanius in the heavily logged area continued to decline decades after logging. Procolobus tephrosceles populations were recovering in the heavily logged areas, but the rate of increase appeared to be slow (0.005 groups/km² per year). Colobus guereza appeared to do well in some disturbed habitats and were found at higher group densities in the logged areas than in the unlogged area. There was no evidence of an increase in Lophocebus albigena group density in the heavily logged area since the time of logging, and there was a tendency for its population to be lower in heavily logged areas than in lightly logged areas. In contrast to the findings from the heavily logged area, none of the species were found at a lower group density in the lightly logged area than in the unlogged area, and group densities in this area were not changing at a statistically significant rate. The results of our study suggest that, in this region, low-intensity selective logging could be one component of conservation plans for primates; high-intensity logging, however, which is typical of most logging operations throughout Africa, is incompatible with primate conservation.     

Levels and trends of polybrominated diphenylethers and other brominated flame retardants in wildlife

In this paper, we review the available data for polybrominated diphenylethers (PBDEs) and other flame retardants in wildlife, with the exception of fishes from Europe and North America which are covered in more detail elsewhere. More data are available for PBDEs than for other compounds, and these show that some of these compounds have become widely distributed in the environment, being found in samples from Europe, Australia, Azerbaijan, North America and the Arctic. Most available data relate to birds and their eggs and marine mammals, but the results of two food web studies are also included. The detection of PBDEs in pelagic marine mammals which feed in deep offshore waters, including baleen whales, indicate that these compounds have found their way into deep-water, oceanic food webs as well as the coastal/shallow sea examples described in detail. In the North Sea study, the most marked increase in lipid-normalised concentrations of six BDE congeners occurred during transfer from predatory fish to marine mammals. In the St. Lawrence Estuary study, marked differences in the ratios observed between species suggested that some fish species may be able to metabolise BDE99.A number of time trend studies have also been conducted, notably in guillemot eggs from Sweden (1969-2000), beluga whales from the Canadian Arctic (1982-1997 and 1989-2001) and from the St. Lawrence Estuary (1988-1999), and ringed seals from the Canadian Arctic (1981-2000). In the temperate latitudes, from these and other studies (e.g. in dated sediment cores), PBDE concentrations began to rise earlier than in those from high latitudes, in line with data for production and use. These trends have now slowed in many cases. Declines could be expected in Europe for many congeners following the cessation of manufacture and use of the penta-mix formulation in the EU, though these are not yet apparent in environmental samples. In Arctic biota, however, the rapidly rising concentrations seen currently in Canada could be expected to continue for some time, reflecting continued production and use of the penta-mix formulation in North America (>95% of the world total) and the impact of long-range atmospheric transport.     

Flow and feeding by swimming scyphomedusae

The mechanical basis of prey capture by scyphomedusae has been largely ignored, despite the importance of these predators in a variety of planktonic ecosystems. Interactions between swimming, fluid motions, and prey capture were examined during 1991–1992 for a species from the three scyphozoan orders having planktonic medusae: Rhizostomeae, Stomolophus meleagris Agassiz, 1862; Coronatae, Linuche unguiculata (Schwartz, 1788); and Semaeostomeae, Cyanea capillata (Linnaeus, 1758). All three species used flow created during bell pulsation to capture prey, but the type of flow used for prey capture and the capture surface morphology were different for each species. The mechanics of capture by these species of diverse morphology and taxonomic affinity suggests that the use of bell pulsation-induced flow for prey entrainment and capture is widespread among the scyphomedusae.     

A nutrient-transfer model to explain the fate of phosphorus and sulphur in a Grazed Hill-Country pasture

A nutrient-transfer model was developed using a mass balance approach to explain the variations in the amounts of soil phosphorus (P) and sulphur (S) found across a range of slopes and aspects in four 10-ha farmlets located in summer-moist hill-country pastures in the southern North Island of New Zealand. The farmlets were continuously grazed by sheep for a period of 12 years, during which time they received a total of 115, 187, 387, 603 and 126, 201, 405, 630 kg ha⁻¹ of P and S, respectively, as single superphosphate (SSP). The model takes account of the effect of topography and local climate on stock behaviour, herbage accumulation and its nutrient content, pasture utilization and the uneven nutrient return through excreta.The developed P model was reliable. The predictions of the transfer model explained 95% of variation in soil P amounts (0–150 mm depth) between farmlets (n=4), 89% of variation between slope units (n=12) and 79% between slope-aspect units (n=36) across all farmlets. When S input parameters were substituted for P parameters, the model was unable to predict the measured soil S levels in any of the four farmlets. Unlike P, S is subject to losses by leaching from these soils. The differences between predicted and measured soil S amounts were used to estimate S leaching losses and pinpoint areas from where they occurred.The concept of modelling the fate of P in P and S fertilized systems and then using the calculated nutrient-transfer functions of the model to evaluate the fate of S provides invaluable information for developing strategies for improving the efficiency of S fertilizer use.     

Ecotoxicity of nickel to Eisenia fetida, Enchytraeus albidus and Folsomia candida

Despite growing concern about the potential adverse effects of elevated nickel concentrations in the environment, only a few toxicity data are available for terrestrial invertebrates. Therefore, chronic toxicity of nickel was assessed for Eisenia fetida, Enchytraeus albidus and Folsomia candida, the three invertebrates for which standard test protocols are available. The 21 d EC50 for the cocoon production of E. fetida was 362 (241-508) mg Ni/kg dry wt. For the reproduction of E. albidus, a 42 d EC50 of 275 (217-346) mg Ni/kg dry wt was observed. The 28 d EC50 for the reproduction of F. candida was 476 (347-671) mg Ni/kg dry wt. The obtained toxicity data were very similar to those of related species reported in literature. Although the presented data can be considered as a step forward in the assessment of the potential risks of nickel in terrestrial environments, further research is needed to evaluate the influence of soil parameters on the toxicity of nickel and to quantify the effect of ageing on bioavailability.     

Assessing the environmental fate of chemicals of emerging concern: a case study of the polybrominated diphenyl ethers

It is suggested that assessments of chemicals of emerging concern can be rationally structured around a multistage process in which fate and risk are evaluated with increasing accuracy as new data become available. An initial tentative and approximate assessment of fate and risk can identify key data gaps and justify and direct further investigations, which progressively improve the reliability of the assessment. This approach is demonstrated for a class of chemicals, the polybrominated diphenyl ethers (PBDEs), which is of increasing concern, but about which there is presently a lack of comprehensive data on properties, sources, fate and effects. Specifically, 20 PBDE congeners are investigated using the suggested approach and research needs are identified.