Dioxin and dioxin-like PCB exposure of non-breastfed Dutch infants

The exposure of humans to PCDD/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like PCBs (dl-PCBs, i.e. polychlorinated non-ortho and mono-ortho biphenyls) occurs predominantly via the intake of food. Young children have a relatively high intake of these substances, due to their high food consumption per kilogram body weight. As the exposure of non-breastfed infants to these compounds has not been assessed before in The Netherlands, we studied the dietary intake of 17 PCDD/Fs and 11 dioxin-like PCBs in 188 Dutch non-breastfed infants between 4 and 13 months. The food intake of the infants was assessed by a 2-d food record. From these data PCDD/F and dioxin-like PCB intake was calculated using PCDD/F and dioxin-like PCB concentrations of food products sampled in 1998/1999 in The Netherlands. The long-term PCDD/F and dioxin-like PCB exposure of the infants was calculated using the statistical exposure model (STEM). For infants of 5 months the chronic exposure to PCDD/F and dioxin-like PCB was 1.1pg WHO-TEQ (toxic equivalents) per kilogram body weight (bw) per day (95th percentile: 1.7pg WHO-TEQ/kg bwxd), which mainly originated from infant formula and vegetables and increased to 2.3pg WHO-TEQ/kg bwxd (95th percentile 3.7pg WHO-TEQ/kg bwxd) for infants just over 1 year old eating the same food as their parents. The percentage of formula-fed infants with an exposure exceeding the TDI of 2pg WHO-TEQ/kg bwxd was 5% at 5 months, 49% at 9 months and 64% at 12 months.     

Courting virtual rivals increase ejaculate size in sticklebacks (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>)

Sperm competition occurs when sperm of two or more males compete to fertilize a given set of eggs. Game-theory models of sperm competition predict that males, which face an increased risk of sperm competition, will invest more sperm in a mating. In the pair-spawning three-spined stickleback ( Gasterosteus aculeatus), males attempt to steal fertilizations (i.e. to sneak) when they are in the courting phase, but not when they are parental. The behaviour of neighbouring males may therefore indicate the risk of sperm competition. We visually confronted males before spawning with computer animations of the same virtual stickleback showing two different behaviours: either courting (high risk of sperm competition) or brood-caring (low risk of sperm competition). We show that males invest significantly more sperm (absolutely and relatively with respect to available sperm in the testes) after the courting stimulus. The relative investment ratio between the courting and the brood-caring treatment was on average 1.75. Three-spined sticklebacks thus seem to assess the risk of sperm competition by the behaviour of neighbours and to adjust their ejaculate accordingly. This result suggests that the evolutionary force of sperm competition has led to precise mechanisms of future risk assessment.     

Sequential female choice and the previous male effect in sticklebacks

Summary Female choice, identified as a major force in sexual selection theory, has recently been demonstrated in a number of species. These tests concentrated on simultaneous choice situations although females have to compare males sequentially in most territorial species, which is the more demanding task. Here it is shown that female three-spined sticklebacks, Gasterosteus aculeatus L., rate sequentially presented males according to their brightness. With increasing costs of sampling the females become less choosy. Furthermore, a male's attractiveness has a significant effect on the female's rating of the next male; a given male is rated higher when preceded by a duller male than by a brighter one and vice versa. Female sticklebacks use a stochastic decision rule in sequential mate choice that is attuned to the attractiveness of the present and previously encountered male. This demonstration of a previous male effect not only indicates an efficient mechanism for finding the best of a number of males but also extends the applicability of sexual selection theory.Offprint requests to: T.C.M. Bakker     

Precious Metals in Municipal Solid Waste Incineration Bottom Ash

Municipal solid waste incineration (MSWI) bottom ash contains economically significant levels of silver and gold. Bottom ashes from incinerators at Amsterdam and Ludwigshafen were sampled, processed, and analyzed to determine the composition, size, and mass distribution of the precious metals. In order to establish accurate statistics of the gold particles, a sample of heavy non-ferrous metals produced from 15 tons of wet processed Amsterdam ash was analyzed by a new technology called magnetic density separation (MDS). Amsterdam’s bottom ash contains approximately 10 ppm of silver and 0.4 ppm of gold, which was found in particulate form in all size fractions below 20 mm. The sample from Ludwigshafen was too small to give accurate values on the gold content, but the silver content was found to be identical to the value measured for the Amsterdam ash. Precious metal value in particles smaller than 2 mm seems to derive mainly from waste of electrical and electronic equipment (WEEE), whereas larger precious metal particles are from jewelry and constitute the major part of the economic value. Economical analysis shows that separation of precious metals from the ash may be viable with the presently high prices of non-ferrous metals. In order to recover the precious metals, bottom ash must first be classified into different size fractions. Then, the heavy non-ferrous (HNF) metals should be concentrated by physical separation (eddy current separation, density separation, etc.). Finally, MDS can separate gold from the other HNF metals (copper, zinc). Gold-enriched concentrates can be sold to the precious metal smelter and the copper-zinc fraction to a brass or copper smelter.     

Transboundary River Floods and Institutional Capacity1

Abstract: While transboundary flood events have become more frequent on a global scale the past two decades, they appear to be overlooked in the international river basin (IRB) cooperation and management arena. The present study therefore combined geopolitical measures with biophysical and socioeconomic variables in an attempt to identify the IRBs with adequate institutional capacity for management of transboundary floods. It also classified basins that would possibly benefit from enlarging the institutional capacity related to transboundary floods. Of the 279 known IRBs, only 78 were represented by a transboundary rivers institution. A mere eight of the 153 identified institutions had transboundary flooding listed as an issue in their mandate. Overall, 43 basins, where transboundary floods were frequent during the period 1985‐2005, had no institutional capacity for IRBs. The average death and displacement tolls were found to be lower in the 37 basins with institutional capacity, even though these basins experienced twice as much transboundary floods with significant higher magnitudes than those in basins without institutional capacity. Overall, the results suggested that institutional capacity plays a role in the reduction of flood‐related casualties and affected individuals. River basins such as the Juba‐Shibeli, Han, Kura‐Araks, Ma, Maritsa, Po, Coco/Segovia, Grijalva, Artibonite, Changuinola, Coatan Achute, and Orinoco experienced more than one transboundary river flood, but have not yet set up any institutions for such events, or signed any appropriate treaties focused on floods. These basins were therefore recommended to consider focusing attention on this apparent lack of institutional capacity when it comes to managing transboundary flood events.     

Functional variation of sperm morphology in sticklebacks

Some theoretical models of sperm competition make the assumption that in fish species with external fertilisation, sperm length relates positively to swimming speed at the expense of sperm longevity. Few studies have tested this assumption. We used the three-spined stickleback, Gasterosteus aculeatus L., to study functional sperm morphology. In this study, the relationship between males’ mean sperm length and fertilisation rate was investigated in vitro in a non-competitive situation. Fertilisation at different time points after sperm release was taken into account, and sperm morphology was quantified from scanning electron microscopy images. The time series of artificial fertilisations demonstrated that males which produced sperm with a longer tail fertilised faster, but their sperm had a shorter lifespan (or activity period). It was further suggested that males that produced sperm with a larger midpiece had greater fertilisation chances later on in the fertilisation process. Thus, in sticklebacks, there exists functional variation in sperm morphology, and sperm tail length is traded off against sperm longevity (or activity).     

Progress on including CCS projects in the CDM: Insights on increased awareness,market potential and baseline methodologies

The inclusion of CO₂ capture and storage (CCS) in the Kyoto Protocol's Clean Development Mechanism (CDM) is still subject to controversy and discussion. A myriad of barriers prevents CCS in the CDM. Apart from political barriers, economic, social and procedural barriers play a role. This paper discusses relevant new results on the human capacity, procedural feasibility and economic potential of CCS in the CDM. The conclusions of a capacity building effort in Africa show that awareness and knowledge are low but that capacity building efforts are well received. A reality check on methodologies for hypothetical CCS projects shows that most of the issues can be resolved, and the CDM institutional arrangements can accommodate CCS. A bottom-up estimate of the potential of natural gas processing CCS in the CDM, based on a previously proprietary database from the oil and gas industry, suggests that there is an annual potential of about 174 MtCO₂ in 2020 in that sector. Most of that potential can be realized at CER prices between $20 and $30/tCO₂ but there is no sign of flooding the CDM market with cheap credits from CCS projects. Despite these results and more open information, the CCS and CDM debate, progress in the negotiations on CCS in the CDM is slow and there is no clear view on a solution.