Studies of inactivation, retardation and accumulation of viruses in porous media by a combination of dye labeled and native bacteriophage probes

Penetration of viruses through soils is governed by the processes of transport, reversible adsorption, accumulation and inactivation. Until now, it was difficult to decouple the latter two processes and accurately predict viral fate. The present work describes a novel method-tracer studies with a mixture of native and fluorescent-dyed bacteriophages-that facilitates parallel quantification of the two processes. When the native phages are experiencing both accumulation and inactivation, the labeled ones are inactivated already and therefore can only be accumulated. Thus the effect of inactivation is applicable to native bacteriophages only and depletion of phage concentration due to inactivation can be elucidated from a total phage balance. The novel approach is exemplified by batch and column studies of the effects of temperature, pH, and saturation, on inactivation of MS2 bacteriophage. A three-parameter model accounting for inactivation, reversible adsorption (i.e., retardation), and accumulation is implemented.     

A flow-through passive dosing system for continuously supplying aqueous solutions of hydrophobic chemicals to bioconcentration and aquatic toxicity tests

A continuous supply of water with defined stable concentrations of hydrophobic chemicals is a requirement in a range of laboratory tests such as the OECD 305 protocol for determining the bioconcentration factor in fish. Satisfying this requirement continues to be a challenge, particularly for hydrophobic chemicals. Here we present a novel solution based on equilibrium passive dosing. It employs a commercially available unit consisting of ∼16 000 polydimethylsiloxane (PDMS) tubes connected to two manifolds. The chemicals are loaded into the unit by repeatedly perfusing it with a methanol solution of the substances that is progressively diluted with water. Thereafter the unit is perfused with water and the chemicals partition from the unit into the water. The system was tested with nine chemicals with log K_OW ranging from 4.1 to 6.3. The aqueous concentrations generated were shown to be largely independent of the water flow rate, and the unit to unit reproducibility was within a factor of ∼2. In continuous flow experiments the aqueous concentrations of most of the study chemicals remained constant over 8 d. A model was assembled that allows prediction of the operating characteristics of the system from the log K_OW or PDMS/water partition coefficient of the chemical. The system is a simple, safe, predictable and flexible tool that generates stable aqueous concentrations of hydrophobic chemicals.     

Wind selectivity of migratory flight departures in birds

Optimal migration theory predicts that birds minimizing the overall time of migration should adjust stopover duration with respect to the rate of fuel accumulation. Recent theoretical developments also take into account the wind situation and predict that there is a time window (a set of days) during which birds should depart when assisted by winds but will not do so if there are head winds. There is also a final day when birds will depart irrespective of wind conditions. Hence, the wind model of optimal migration theory predicts that birds should be sensitive to winds and that there should be a correlation between departures and winds blowing towards the intended migration direction. We tested this assumption by tracking the departures of radio-tagged passerines during autumn migration in southern Sweden. Our birds were moderately to very fat when released and therefore energetically ready for departure. There was a significant correlation between direction of departure and wind direction. We also found that during days when birds departed there was a significantly larger tail wind component than during days when birds were present but did not depart. Our results show that passerines do take the current wind situation into account when departing on migratory flights. We also briefly discuss possible clues that birds use when estimating wind direction and strength. The inclusion of wind is an important amendment to optimal migration theory of birds and should be explored further. Received: 1 March 1999 / Received in revised form: 4 October 1999 / Accepted: 16 October 1999     

Farmers’ markets – linking food consumption and the ecology of food production?

Urban and industrialised societies usually involve little connection between consumers and the resource base upon which the production of goods depends. Changing this situation could potentially enhance social and ecological sustainability. This study explored ecological aspects of the educational role of local food supply, with the aim of identifying signs of enhanced consumer understanding or awareness of the ecology of food production resulting from producer–consumer interaction. A series of qualitative interviews were carried out with customers at a farmers’ market in Stockholm. The results showed that the interviewees were mainly concerned with quality, price and taste, and not production conditions. In addition, a number of interviewees experienced a sense of trust when shopping at the market. We found few examples of contributions to ecological knowledge among customers at the market, but there were some examples of learning opportunities. The local food supplied by the market reminded customers of the seasonality of production. Stallholders also provided information on how to store, prepare and cook vegetables, which may encourage a change in diet that is preferable from an environmental standpoint.     

Organophosphate and phthalate esters in indoor air: a comparison between multi-storey buildings with high and low prevalence of sick building symptoms

An extensive study has been conducted on the prevalence of organophosphorous flame retardants/plasticizers and phthalate ester plasticizers in indoor air. The targeted substances were measured in 45 multi-storey apartment buildings in Stockholm, Sweden. The apartment buildings were classified as high or low risk with regard to the reporting of sick building symptoms (SBS) within the project Healthy Sustainable Houses in Stockholm (3H). Air samples were taken from two to four apartments per building (in total 169 apartments) to facilitate comparison within and between buildings. Association with building characteristics has been examined as well as association with specific sources by combining chemical analysis and exploratory uni- and multivariate data analysis. The study contributes to the overall perspective of levels of organophosphate and phthalate ester in indoor air enabling comparison with other studies. The results indicated little or no difference in the concentrations of the target substances between the two risk classifications of the buildings. The differences between the apartments sampled within (intra) buildings were greater than the differences between (inter) buildings. The concentrations measured in air ranged up to 1200 ng m(-3) for organophosphate esters and up to 11?000 ng m(-3) for phthalate esters. Results in terms of sources were discerned e.g. PVC flooring is a major source of benzylbutyl phthalate in indoor air.     

Environmental exposure to POPs and heavy metals in urban children from Dhaka, Bangladesh

Persistent organic pollutants (POPs) and heavy metals are well known environmental pollutants. Even though numerous studies have been carried out to assess human exposures to these compounds, there is still a lack of data on humans from developing countries, especially in underprivileged children. The objective of this study was to assess the exposure to POPs and heavy metals in children from Dhaka, Bangladesh. One specific aim was to investigate whether children working at, or living close to, open waste disposal sites (WDSs) were more heavily exposed than other urban children. In 2008, blood and serum were collected from 73 children aged 7-16 from five neighbourhoods. Some of the children lived and worked at WDSs (N = 31), others lived next to a WDS (N = 17), whereas some children lived far from such sites (N = 25). Blood levels of lead (B-Pb), cadmium (B-Cd), and selenium (B-Se) were determined by ICP-MS for all subjects. The metal levels were high, with B-Pb overall mean 120 μg L(-1) (range 40-220), B-Cd 0.74 μg L(-1) (0.22-4.1), and B-Se 120 μg L(-1) (81-170). There were no marked differences between children from the different neighbourhoods, or between WDS workers and other children. PCB levels were low and with no contrast between neighbourhoods, for CB-153 the overall mean was 7.0 ng g(-1) fat (2.8-51). In contrast, high levels of DDTs were observed in all children, for 4,4'-DDE 1300 ng g(-1) fat (420-4600), and for 4,4'-DDT 326 ng g(-1) fat (44-1400), indicating ongoing exposure. PBDE levels were low, and BDE-209 was quantitated mainly in children working at or living close to WDSs. In conclusion, the high levels of DDTs, lead and cadmium observed in children from Dhaka are of concern. Many children were exposed at levels where health effects have been observed, or at levels without safety margins.     

The Swedish Environmental Classification and Information System for Pharmaceuticals — An empirical investigation of the motivations,intentions and expectations underlying its development and implementation

In 2005 the Swedish Association of the Pharmaceutical Industry (LIF) initiated a national environmental classification and information system for pharmaceuticals. This investigation reports the results from a survey, conducted among the persons involved in the start-up process. The aim of this study is to generate knowledge contributing to the clarification of the motivations, expectations, and intentions underlying the development and implementation of the system. The decision to implement a classification and information system for pharmaceuticals was the result of a combination of several driving forces, mainly political pressure and a possibility to increase the industries' goodwill, while at the same time keeping the process under the industries' control. The expected possible effects of the system, other than increased goodwill, are according to this survey assumed to be low. The system offers little guidance for end-users in the substitution of one pharmaceutical for another. One possible reason for this could be that LIF needs to observe the interests of all its members' and should not affect competition. The affiliation of the involved actors correlates to how these actors view and value the system, but this has not hampered the collaborative process to develop and implement it.     

Bimodal orientation and the occurrence of temporary reverse bird migration during autumn in south Scandinavia

Extensive ringing data from a coastal site (Falsterbo Bird Observatory) in southwesternmost Sweden were used to investigate the occurrence of reverse autumn migration among 20 passerine bird species of widely different migration categories. The data demonstrate that reverse migration is a widespread and regular phenomenon among nocturnal as well as diurnal migrants and among irruptive migrants, temperate zone migrants, and long-distance migrants destined for tropical winter quarters. The reoriented movements were directed approximately opposite to the normal migration direction, i.e. between NNW and ENE from the coast and towards inland. Median distances of reverse movements varied between 9 and 65 km. Some individuals of irruptive and partial migrants settled to winter in the reverse direction. Bird species with relatively small fat reserves at capture were more likely to perform reverse migratory movements than species with larger fat deposits. In two species birds performing forward migration were significantly heavier within 10 days after capture than individuals performing reverse movements. The reoriented movements probably are of adaptive significance for birds confronted with the sea and pre-disposed to refuelling during migration. A bimodal orientation mechanism will bring the birds from an area with high competition for food and high predation risk to more suitable resting and feeding grounds before resuming migration in the forward direction and crossing the barrier. Received: 11 July 1995/Accepted after revision: 19 November 1995     

Distribution,fate and persistence of organochlorine compounds formed during production of bleached pulp

The processes governing distribution of a xenobiotic compound discharged initially into the environment are discussed, and attention is drawn to (a) binding to organic matter in the sediment phase which affects both persistence and toxicity to biota and (b) the role of atmospheric transport for compounds of low water solubility and high vapour pressure. Important limitations in the use of sum parameters such as EOCI are pointed out. The important distinction between biodegradation and biotransformation is pointed out, and significant experimental determinants noted. Pathways for the aerobic metabolism of chlorophenolic compounds are discussed, and attention is drawn to the role of O‐methylation as an environmentally significant alternative to biodegradation. Evidence for the biodegradation of chlorinated aliphatic acids and hydrocarbons under both aerobic and anaerobic conditions is presented. Anaerobic metabolism of chlorophenolic compounds is discussed with respect to (a) de‐O‐methylation of chloroguaiacols, (b) dechlorination of chlorocatechols and (c) reduction of chlorovanillins. It is emphasized that current evidence provides a complex metabolic picture, and that only partial dechlorination may occur. Brief attention is given to the important issue of the persistence of chlorolignin, and attention drawn to technical issues which render this problem difficult of access by traditional procedures. Biohalogenation—particularly by fungi—is noted, though its quantitative contribution cannot be estimated at the moment. A number of important unresolved issues are underscored: (a) the problem of determining rates of microbial reactions which may be translated to environmental situations, (b) the cardinal role not only of the number of chlorine atoms in an aromatic compound but also the substitution pattern and (c) limitations in current understanding of the role of anaerobic bacteria in bringing about biodegradation and biotransformation.     

12th EuCheMS International Conference on Chemistry and the Environment

Environmental Science and Pollution Research -