Effects of point-source PCB contamination on breeding performance and post-fledging survival in the dipper Cinclus cinclus

Despite widespread information on the incidence and biochemical effects of polychlorinated biphenyls (PCBs) in birds, field studies of effects on population processes are still scarce. This is particularly so in passerines. We therefore assessed breeding performance and post-fledging survival in dippers, Cinclus cinclus, breeding along the Afon Mule, a Welsh river where previous work indicated locally elevated PCB concentrations. We hypothesised that marked toxicological effects, including endocrine disruption, would be detectable as altered clutch-size, hatching success, nest success, brood-size, post-fledging survival or recruitment to the breeding population. Congener-specific analysis of PCBs in failed and deserted dipper eggs during 1990-93 revealed that geometric mean concentrations were four to 20 times higher along the Mule than elsewhere in Wales, UK. PCB signatures also varied highly significantly from other locations, with congeners 138, 153 and 180 dominant at the contaminated site, but 118 or 170 more frequent in eggs elsewhere. Subsequent analysis of surface runoff confirmed a small breaker's yard as a point source. Neither laying dates, clutch-sizes, brood-sizes, nest failure nor hatching failure along the contaminated Mule (n=46 breeding attempts and 218 eggs) differed significantly from dippers along adjacent reference rivers (n=82 breeding attempts and 315 eggs) or Welsh rivers as a whole (n=332 breeding attempts and 1534 eggs). Subsequent recaptures of breeding dippers ringed initially as nestlings were nearly identical between the Mule (7.7% of 182 nestlings), the reference set (7.5% of 323 nestlings) and all other Welsh rivers (7.3% of 2821 nestlings). These data illustrate the value of congener-specific analysis of bird's eggs in indicating local PCB sources. The data show also that PCBs can occur in dipper eggs at total concentrations of 0.49 (geometric mean)-1.29 (upper quartile) microg g(-1) wet mass without effects on breeding performance and survival. These values are below those at which biochemical or reproductive effects on other passerines have been detected, but above current concentrations in any other population of European dippers for which PCB data are available. Population effects by PCBs on European dippers are therefore unlikely. Survivors from locally contaminated sites like that in our study might allow field assessments of second-generation effects on breeding performance in wild birds that have developed under PCB exposure.     

A pond mesocosm study to determine direct and indirect effects of lindane on a natural zooplankton community

We assessed the threshold concentrations for toxic effects by lindane on a zooplankton community using mesocosms in a natural pond. Enclosures (1000 litres) were treated to give mean concentrations of 0, 2, 6, 12, 18, 24, and 50 microg litre(-1) over a test period of 39 days. Larvae of the phantom midge Chaoborus flavicans showed a high susceptibility to lindane and were virtually eliminated from enclosures with > or =12 microg litre(-1) 4 days after application. Populations of cyclopoid nauplii (Eucyclops serrulatus) were reduced at a lindane concentration of 2 microg litre(-1) and showed high mortality after 11 days exposure to > or =6 g litre(-1). No lindane-induced effects could be seen in the cladoceran species Daphnia longispina and Chydorus sphaericus. Rotifer species were probably not directly affected by lindane; however loss of the principal predator Chaoborus was accompanied by an increase in the numbers of Asplanchna priodonta. A simultaneous decrease in Keratella quadrata possibly reflected predation since its decline showed no dose-response relationship with lindane and it is among the major prey of Asplanchna. Such complex secondary effects, occurring through trophic interactions between a predator and two co-occurring prey, would not have been predicted from single-species toxicity tests. These, and effects on cyclopoid populations that occurred predominantly through the mortality of nauplii, demonstrate the value of toxicological studies on natural communities. We conclude that a combination of laboratory and field investigations, coupled with mono-species and community assessments, provide the best route for understanding the effects of toxicants such as lindane for regulatory purposes.     

Grit ingestion as a source of metal exposure in the spruce grouse, Dendragapus canadensis

The objective of this study was to determine if ingestion of grit was a source of metal exposure to the spruce grouse, Dendragapus canadensis. A secondary objective was to assess whether grit could provide a supplemental source of essential minerals to their diet. Ca, P, Mg, S, Zn, Cu, Ni, Co, Cr, Fe, Mn, Al, Pb and Cd of liver (adult, yearling, chicks), crop and gizzard contents (adults) were determined for grouse collected from a relatively pristine boreal forest region of north-central Ontario, Canada. With the exception of Cd liver, concentrations were independent of age [one-way analysis of variance (ANOVA); p>0.004). Zn liver concentrations tended to be greater in adults than yearlings and chicks (one-way ANOVA; p=0.02). Liver concentrations of Cd increased with age (r=0.99; p<0.001). The contribution of crop items to total gizzard elemental content was element specific; crop contents contributed 90-100% of Mn and Zn, 70% for P and Ca, 60% for Pb, 50% for S, and 0-25% for Cu, Mg, Ni, Al, Fe, Co, Cr and Cd to the total elemental concentration of gizzard contents (crop plus grit). Incorporation of grit by grouse could, therefore, constitute an important source of essential macro-(Ca, P, Mg, S) and trace elements (Cu, Fe) but not for Mn or Zn. However, in addition to providing nutrients to the bird, ingestion of grit results in exposure to toxic trace metals such as Cd which in turn is accumulating in the liver. Research directed at determining grit turnover time, and hence metal exposure rates, in bird species which ingest grit to aid in food digestion is required. The toxicological significance of Cd exposure to grit-ingesting birds needs attention.     

Topsoil (0-5 cm) composition in eight arctic catchments in northern Europe (Finland, Norway and Russia)

Frozen topsoil samples (0-5 cm) were collected during March/April 1994 in eight Arctic catchments in northern Europe (four in Russia, three in Finland, one in Norway), at different distances and in different wind directions from the emissions of the Russian mining, roasting and smelting industry on the Kola Peninsula. Between 14 and 25 sites were sampled in each of the eight catchments ranging in size from 12 to 35 km2. Results show that close to the smelters in Monchegorsk and Nikel, topsoil is clearly enriched in Ag, As, Bi, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, Se, Te and V. Cu and Ni median contents in topsoils collected close to Monchegorsk are about 600 times higher than in the Finnish catchments. The effect of open-cast mining and waste dumps of alkaline rocks from the nephelinite industry near Kirovsk can be seen in the elevated contents of Al, Ba, K, La, Mn, Na, Sr, Ti, Y and Zn in topsoil collected in a nearby catchment. For many elements, however, variations observed in single catchments are as great as the total regional variation. Several elements (e.g. Cd, Hg, Cu, Ni, Pb, S, Zn) show strong positive correlation between the organic content of the sample and the element content observed. Thus it is necessary to determine the organic content of the samples and correct the element levels when using depth-related soil samples (here, the 0-5 cm topsoil layer) for regional mapping.     

Principles and perspectives

BACKGROUND, AIM AND SCOPE: With respect to the enormous increase of chemical production in the last decades and the tens of thousands of individual chemicals on the market, the permanent improvement of chemical management is a permanent target to achieve the goals of sustainable consumption and production set by the WSSD in Johannesburg 2002. MAIN FEATURES: Several approaches exist to describe sustainability of chemistry. However, commonly agreed criteria are still missing. There is no doubt that products of modern chemistry help to achieve important goals of sustainability and that significant improvements have occurred regarding direct releases from production sites, but several facts demonstrate that chemistry is far from being sustainable. Still too many chemicals exhibit hazardous characteristics and pose a risk to health and environment. Too many resources are needed to produce chemicals and finished products. RESULTS AND CONCLUSION: Therefore, a strategy for sustainability of chemistry should be developed which comprises the following main elements: 1. Sustainable chemicals: sustainable chemical management includes a regulatory framework which makes no difference between new and existing chemicals, contains efficient information flow through the supply chain which allows users to handle chemicals safely and offers an authorisation procedure and/or an efficient restriction procedure for substances of high concern. This regulatory scheme should promote the development of inherently safe chemicals. 2. Sustainable chemical production: Sustainable chemical production needs the development and implementation of emerging alternative techniques like selective catalysis, biotechnology in order to release less CO2 and less toxic by-products, to save energy and to achieve higher yields. Information exchange on best available techniques (BAT) and best environmental practices (BEP) may help to promote changes towards more sustainability. 3. Sustainable products: An integrated product policy which provides a framework for sustainable products promotes the development of products with a long-term use phase, low resource demand in production and use, low emission of hazardous substances and properties suitable for reuse and recycling. This may be promoted by eco-labelling, chemical leasing concepts and extended information measures to enhance the demand of consumers and various actors in the supply chain for sustainable products. RECOMMENDATION AND PERSPECTIVE: Important tools for the promotion of sustainable chemistry are the abolition of barriers for innovation in legislation and within the chemical industry, more transparency for all users of chemical products, a new focus on sustainability in education and research, and a new way of thinking in terms of sustainability.     

Investigating missing sources of glyoxal over China using a regional air quality model (RAMS-CMAQ)

Currently, modeling studies tend to significantly underestimate observed space-based glyoxal(CHOCHO) vertical column densities(VCDs), implying the existence of missing sources of glyoxal. Several recent studies suggest that the emissions of aromatic compounds and molar yields of glyoxal in the chemical mechanisms may both be underestimated, which can affect the simulated glyoxal concentrations. In this study, the influences of these two factors on glyoxal amounts over China were investigated using the RAMS-CMAQ modeling system for January and July 2014. Four sensitivity simulations were performed, and the results were compared to satellite observations. These results demonstrated significant impacts on glyoxal concentrations from these two factors.In case 1, where the emissions of aromatic compounds were increased three-fold,improvements to glyoxal VCDs were seen in high anthropogenic emissions regions. In case 2, where molar yields of glyoxal from isoprene were increased five-fold, the resulted concentrations in July were 3–5-fold higher, achieving closer agreement between the modeled and measured glyoxal VCDs. The combined changes from both cases 1 and 2 were applied in case 3, and the model succeeded in further reducing the underestimations of glyoxal VCDs. However, the results over most of the regions with pronounced anthropogenic emissions were still underestimated. So the molar yields of glyoxal from anthropogenic precursors were considered in case 4. With these additional mole yield changes(a two-fold increase), the improved concentrations agreed better with the measurements in regions of the lower reaches of the Yangtze River and Yellow River in January but not in July.