Waste disposal and the recommendations of the International Commission on Radiological Protection – Challenges for radioecology and environmental radiation protection

The 2007 Recommendations of the International Commission on Radiological Protection (ICRP) represent a change from a process-based to an exposure-based approach, where exposure situations are categorised as planned, emergency, and existing exposure situations. Although the new Recommendations contain further changes based on, inter alia, scientific developments since the publication of the 1990 Recommendations, they overall represent more continuity than change – a notable exception being the direct consideration of environmental protection. The implications of the new Recommendations for radioactive waste management are fairly marginal, as earlier recommendations in this area are still considered valid. This communication provides a brief overview of the current ICRP system for radiological protection as applied to radioactive waste management, as well as an outlook including the possibility of using the developing ICRP system for management of environmental effects as an ‘alternative way of reasoning’ when building the safety case for a specific waste disposal concept.     

Ecology,evolution, and management strategies of northern pike populations in the Baltic Sea

Baltic Sea populations of the northern pike (Esox lucius) have declined since the 1990s, and they face additional challenges due to ongoing climate change. Pike in the Baltic Sea spawn either in coastal bays or in freshwater streams and wetlands. Pike recruited in freshwater have been found to make up about 50 % of coastal pike stocks and to show natal homing, thus limiting gene flow among closely located spawning sites. Due to natal homing, sub-populations appear to be locally adapted to their freshwater recruitment environments. Management actions should therefore not involve mixing of individuals originating from different sub-populations. We offer two suggestions complying with this advice: (i) productivity of extant freshwater spawning populations can be boosted by modifying wetlands such that they promote spawning and recruitment; and (ii) new sub-populations that spawn in brackish water can potentially be created by transferring fry and imprinting them on seemingly suitable spawning environments.     

Sulfur recirculation for increased electricity production in Waste-to-Energy plants

Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop.The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO₃ concentrations, which may otherwise induce low temperature corrosion.In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60–90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion.     

Persistent organic pollutants (POP) in a benthic omnivore--a comparison between lake and stream crayfish populations

We investigated the accumulation of PCB and DDT in crayfish populations in 10 streams in southern Sweden. The results were compared with an earlier study on crayfish in lakes from the same area. We found that the concentration of pollutants in crayfish did not differ between the two types of systems. Variation in body burden was higher in stream living crayfish probably because of the higher influence from pollutants deposited in the catchment area and the more dynamic transport in streams. In streams, p,p'-DDE concentrations were positively correlated to trophic status (total phosphorous) while PCB did not show any correlation with the nutrient regime. Further, mean SigmaPCB and p,p'-DDE concentrations in crayfish did not correlate in streams. We suggest that the sources of the two pollutants differ for stream living crayfish. The results indicate that crayfish in streams are affected to a higher degree to pollutants in the catchment area and the precipitation regime. In lakes, internal processes govern uptake of pollutants in crayfish.     

An attempt to measure the flow of chlorinated hydrocarbons, such as PCBs, from water to air in the field

A field sampling device to study the transport of aromatic, persistent chlorinated hydrocarbons from water to air was constructed. It was tested in large, outdoor artificial ponds contaminated with polychlorinated biphenyls (PCBs). The PCB compounds volatilised to air at a rate of 0.9 to 9.6 ng m(-2) h(-1) depending on levels of PCBs in the water and water temperature.     

Low levels of persistent organic pollutants (POPs) in New Zealand eels reflect isolation from atmospheric sources

Polychlorinated biphenyls (PCBs) and organic pesticides (i.e., DDTs) were measured in long finned eels (Anguilla dieffenbachii) in 17 streams on the west coast of South Island, New Zealand. Very low levels of PCBs and low levels of ppDDE were found. The concentrations of PCBs and ppDDE were not correlated within sites indicating that different processes determined the levels of the two pollutants in New Zealand eels. The PCBs probably originate from atmospheric transport, ppDDE levels are determined by land use and are higher in agriculture areas. The low contamination level of these aquatic systems seems to be a function of a low input from both long and short-range transport as well as few local point sources. No correlation could be found between lipid content and persistent organic pollutants (POPs) concentration (as shown in previous studies) in the eels which could be explained by low and irregular intake of the pollutants.     

Non-steroidal anti-inflammatory drugs in Indian rivers

Pharmaceutical concentration data for Indian surface waters are currently scarce. Sewage often enters Indian rivers without prior treatment, and so previously reported environmental concentrations from regions with routinely implemented sewage treatment cannot simply be used to predict concentrations in Indian surface water. Improved knowledge of pharmaceutical concentrations in Indian waters would enable determination of potential risks posed to aquatic wildlife and human health in this region. The concentrations of five common non-steroidal anti-inflammatory drugs (NSAIDs; diclofenac, ketoprofen, naproxen, ibuprofen, and acetylsalicylic acid) were determined in surface waters from 27 locations of the Kaveri, Vellar, and Tamiraparani Rivers in southern India. The samples were extracted by solid-phase extraction and analyzed by GC-MS. The measured concentrations of four of the five drugs in this reconnaissance were relatively similar to those reported elsewhere (ND–200 ng/l); however, acetylsalicylic acid, the most readily degradable of the investigated drugs, was found at all sites and at considerably higher concentrations (up to 660 ng/l) than reported in European surface waters. This is the first report on the occurrence of NSAIDs in Indian rivers. The finding of elevated concentrations of acetylsalicylic acid is most likely a result of direct discharges of untreated sewage. Therefore, readily degradable pharmaceuticals may present larger concern in regions without consistent sewage treatment. Based on measured environmental concentrations, the risks of direct toxicity to aquatic wildlife and of humans consuming the water are discussed.     

Large variation in breast milk levels of organohalogenated compounds is dependent on mother's age, changes in body composition and exposures early in life

We identified factors that are important determinants of body burdens (breast milk levels) of polychlorinated biphenyls (PCBs), dioxins (polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)) and polybrominated diphenyl ethers (PBDEs). PCBs, PCDD/Fs and PBDEs were analysed in breast milk from up to 325 first-time mothers in Uppsala, Sweden, who delivered between 1996 and 2006. Hierarchical clustering was used as a method for identification of groups of compounds with common sources of exposure and similar toxicokinetics. Based on correlations between levels of single compounds/congeners in breast milk, distinctly separated clusters were formed, strongly dependent on structural similarities of the organohalogen molecules. In a multiple regression model, levels of PCBs (except PCB 28), PCDD/Fs and BDE-153 were positively associated with age of the mother and weight loss after delivery and inversely associated with pre-pregnancy BMI (body mass index) and weight gain during pregnancy. Higher levels of mono-ortho PCB TEQ, non-ortho PCB TEQ and BDE-153 in milk were found among women with high physical activity. Women who were breastfed during infancy and grew up on the Baltic coast of Sweden, with high availability of contaminated fish from the Baltic sea, had higher levels of PCBs and PCDD/Fs in breast milk indicating that exposure early in life from breast milk and contaminated fish may still affect body burdens at the time of pregnancy. The importance of current consumption of fatty Baltic fish as a source of exposure was supported by the positive association with breast milk levels of mono-ortho PCB TEQ, PCDF TEQ and BDE-153. The results show that, in contrast to the lower brominated PBDE congeners, the hexa-brominated BDE-153 resembles the chlorinated compounds with regards to determinants in breast milk. This suggests that some of the PBDEs may have toxicokinetic properties and that are similar to the PCBs and PCDD/Fs. Our results show that a few simple advices to women regarding weight changes in connection with pregnancy and consumption of contaminated fatty fish during the whole lifetime may lower the levels of dioxins in breast milk by up to 60%.     

Chondrodysplasia punctata (CDP) with features of the tibia-metacarpal type and maternal phenytoin treatment during pregnancy

We describe a 2-year-old boy with chondrodysplasia punctata (CDP). The boy was exposed to phenytoin, in combination with carbamazepine, during pregnancy. There has been previous evidence for a connection between phenytoin exposure during pregnancy and chondrodysplasia punctata. The boy had clinical and some radiological characteristic features of CDP, of the tibia-metacarpal type. We know of no other report on a child exposed to phenytoin during pregnancy who developed CDP of this type. Copyright © 2002 John Wiley & Sons, Ltd.     

Effects of enhanced UVB radiation on a marine benthic diatom mat

In order to study the ecophysiological response of a natural diatom-dominated microbial mat to an enhanced level of ultraviolet-B radiation (UVBR), intact sediment cores from a shallow microtidal bay on the Swedish west coast were incubated in an outdoor flow-through system and exposed to either no UVBR or to an artificially enhanced level of UVBR. The microbial mat was cohesive and dominated by the large (≈ 400 μm) motile diatom Gyrosigma balticum. Functional response to UVBR was assessed by measuring carbon fixation (¹⁴C) and allocation of photosynthetic products. Sediment oxygen microprofiles were measured as indicators of the balance between the photosynthetic and respiratory activity of the community. Structural variables included biomass and composition of microalgae, pigment composition (HPLC), content of UV-absorbing compounds, and composition of fatty acids. An enhanced level of UVBR resulted in significant functional changes in the microalgal community. Significantly decreased carbon fixation and lower net oxygen production (as calculated from oxygen microprofiles) suggest that primary productivity in the type of microbial mat studied is potentially sensitive to an enhanced level of UVBR. The pattern of carbon allocation hinted a change as to the photosynthetically active part of the community when exposed to UVBR, indicating a differential sensitivity among algal cells. Despite significant functional effects, pigment or algal composition were not significantly affected by enhanced UVBR. The concentration of UV-absorbing compounds was low and did not increase at UVBR exposure. Due to the short duration of the experiment (4 d), a change in algal biomass or composition was not to be expected. Moreover, the thickness of the sampled sediment layer, may have contributed to the lack of observed structural effects of enhanced UVBR. Visual observations suggested that UVBR affected the motility of G. balticum. This study, as well as other experiments with a similar diatom mat, suggest that vertical migration is a key mechanism to be further studied in relation to UVBR exposure of diatom-dominated microbial mats. Received: 7 September 1996 / Accepted: 8 October 1996