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A Baun

Publications and source records attributed to A Baun.

8 recordsLinked to original sources
PubMed2006

A methodology for ranking and hazard identification of xenobiotic organic compounds in urban stormwater.

The paper presents a novel methodology (RICH, Ranking and Identification of Chemical Hazards) for ranking and identification of xenobiotic organic compounds of environmental concern in stormwater discharged to surface water. The RICH method is illustrated as a funnel fitted with different filters that sort out problematic and hazardous compounds based on inherent physico-chemical and biological properties. The outcomes of the RICH procedure are separate lists for both water phase and solid phase associated compounds. These lists comprise: a justified list of compounds which can be disregarded in hazard/risk assessments, a justified list of stormwater priority pollutants which must be included in hazard/risk assessments, and a list of compounds which may be present in discharged stormwater, but cannot be evaluated due to lack of data. The procedure was applied to 233 xenobiotic organic chemicals (XOCs) of relevance for stormwater. Of these 233 compounds, 121 compounds were found to be priority pollutants with regard to solids phases (i.e. suspended solids, soil, or sediments) when stormwater is discharged to surface water and 56 compounds were found to be priority pollutants with regard to the water phase. For 11% of the potential stormwater priority pollutants the screening procedure could not be carried out due to lack of data on basic physico-chemical properties and/or data on bioaccumulation, resistance to biodegradation, and ecotoxicity. The tiered approach applied in the RICH procedure and the focus on the phases relevant for monitoring or risk assessment in the aquatic environment refines the list of "compounds of concern" when compared to the outcome of existing classification schemes. In this paper the RICH procedure is focused on effects in the aquatic environment exemplified with xenobiotic organic compounds (XOCs) found in urban stormwater, but it may be transferred to other environmental compartments and problems. Thus, the RICH procedure can be used as a stand-alone tool for selection of potential priority pollutants or it can be integrated in larger priority setting frameworks.

Biodegradation, Environmental↗
PubMed2006

Transfer of hydrophobic contaminants in urban runoff particles to benthic organisms estimated by an in vitro bioaccessibility test.

An in vitro bioaccessibility test was applied for assessing the transfer of polycyclic aromatic hydrocarbons (PAHs) present in road dust, into benthic organisms living in a receiving water body. The road dust is supposed to be urban runoff particles under wet weather conditions. Sodium dodecyl sulfate (SDS) solution was used as a hypothetical gut fluid. Pyrene, fluoranthene and phenanthrene were the main PAH species in the SDS extractable fraction of road dust, as well as the whole extract. Benzo(ghi)perylene showed relatively low concentrations in the SDS extract in spite of a high concentration in the original dust. The PAH composition in benthic organisms (polychaetes) did not correspond with that of the surrounding sediment and the PAHs detected were also detected in high concentrations in the SDS extract of road dust. When testing the toxicity of the extracted contaminants by a standardised algal toxicity test, SDS extracts of a detention pond sediment showed higher toxicity than the pore water of the corresponding sediment. Sediment suspension showed a comparative toxicity with 0.1% SDS extract. From the results, the in vitro bioaccessibility test seems more suitable to evaluate the exposed contaminants than the traditional organic solvent extraction method and the SDS extracted fraction is applicable to toxicity tests reflecting the digestive process.

Animals↗
PubMed2005

Chemical hazard identification and assessment tool for evaluation of stormwater priority pollutants.

Assessment of chemical hazards is a critical issue, which have to be dealt with when evaluating different strategies for sustainable handling of stormwater. In the present study, a methodology for identifying the most critical and representative chemical pollutants was developed. A list of selected stormwater priority pollutants (SSPP-list) is the out-put from the procedure. Two different strategies for handling of stormwater were considered; discharge into a surface water recipient and infiltration. However, the same methodology can be used for other types of wastewater and other strategies for handling and treatment. A literature survey revealed that at least 656 xenobiotic organic compounds (XOCs) could be present in stormwater. In the next step, 233 XOCs were evaluated with respect to the potential for being hazardous towards either aquatic living organisms or humans, or causing technical or aesthetical problems. 121 XOCs were found have at least one of these negative effects, while 26 XOCs could not be assessed due to the lack of data. The hazard assessment showed that 40 XOCs had a PEC/PNEC ratio above one., e.g. they should be considered as priority pollutants. The final step is the expert judgement, which resulted in a final SSPP-list containing 16 selected priority pollutants.

Rain↗
PubMed2005

A novel method for evaluating bioavailability of polycyclic aromatic hydrocarbons in sediments of an urban stream.

Hydrophobic organic pollutants in urban wet weather discharges can accumulate in the sediments of receiving waters and may have adverse effects on the ecological system, especially on benthic organisms. Here, a novel method is developed for evaluating the bioavailability of such hydrophobic organic pollutants by considering the digestive guts in deposit-feeding polychaetes. We compared the amount of polycyclic aromatic hydrocarbons (PAHs) extracted by an organic solvent and by sodium dodecyl sulfate (SDS) solution (as a hypothetical digestive gut fluid of polychaetes) and interpreted the ratio of the two values as bioavailability. The sediment extracts were applied to bacterial acute toxicity tests and algal growth inhibition tests. Sediment samples were collected from an urban stream system receiving wet weather discharges. The bioavailability of the total amount of 12 PAHs in the sediments was in the range 14-38% based on the results from the GC/MS determination of the two different extracts. Lower molecular PAHs showed higher bioavailability compared to the higher molecular ones. The sediment extracts were shown to be toxic towards both algae and bacteria. The SDS extracts showed similar or higher toxicity in the two biotests compared to the organic solvent extracts in spite of their lower PAHs content.

Aliivibrio fischeri↗
PubMed2004

Xenobiotic organic compounds in leachates from ten Danish MSW landfills--chemical analysis and toxicity tests.

A monitoring program comprising chemical analysis and biological toxicity testing of leachate samples from 10 Danish landfills (six engineered and four uncontrolled) revealed the presence of 55 different xenobiotic organic compounds (XOCs) and 10 degradation products of XOCs. The compounds belong to the following groups: BTEX, C3-benzenes, bicyclo compounds, napthalenes, chlorinated aliphatics, phenols (chloro-, methyl-, dimethyl, nonyl-), pesticides, and phthalates. Concentrations of single XOCs ranged from <0.1 to 2220 microg/L. A pesticide screening including 101 different compounds resulted in detection of 18 pesticides and three degradation products. The findings of degradation products of toluene, phenols, phthalates, pesticides, and nonylphenol ethoxylates show that degradation occurred inside the landfills. In biotests with bacteria and algae it was found that the non-volatile organic compounds were toxic as the samples only needed to be pre-concentrated from 1.3 to 9.4 times to give 50% inhibition of the test organisms. One of the ten samples proved to be genotoxic in the umuC test after 141 times pre-concentration. A major part of the organic chemicals causing toxicity remains unknown and it is recommended to combine chemical analyses and biotests in future monitoring programs.

Bacteria↗
PubMed2002

[Bilateral bone anchored hearing aid management of children with external ear dysplasia and/or ear canal atresia].

BACKGROUND AND OBJECTIVE: The literature gives hardly any information about the benefits for children of using a bilateral bone-anchored hearing aid (BAHA) as opposed to a bilateral conventional bone conducting hearing aid. PATIENTS AND METHODS: Within a period of 12 years, three children were selected for treatment with bilateral BAHA. At the time of surgery, the children were aged between 8 and 10 years. Two of the children suffered from Franceschetti syndrome and one child from Goldenhar's syndrome. The clinical course of these three patients is presented. RESULTS: In all cases, treatment with BAHA was beneficial according to subjective and objective criteria despite localized inflammatory complications in two of the three cases. CONCLUSIONS: The bilateral use of BAHA should be considered more frequently as an alternative to conventional bone conducting hearing aids even for children.

Audiometry, Pure-Tone↗
PubMed1999

Correcting for toxic inhibition in quantification of genotoxic response in the umuC test.

An improved procedure for quantification of results from the umuC tests for genotoxicity is presented. The calculation method better separates toxic growth inhibition (cytotoxicity) from genotoxic effects than currently used methods and therefore, greatly extends the applicability of genotoxicity tests on environmental samples. The basic principle is to normalize the genotoxic response compensating for both decreasing biomass and growth rate reduction that results from cytotoxicity. The improved method and the currently used method was compared for umuC tests on the pure compounds: methylmethanesulfonate (MMS), N-methyl-N'-nitro-N-nitroguanidine (MNNG), sodium azide (NaN3), and 4-nitroquinoline-1-oxide (4-NQO). For compounds with no or low cytotoxicity, the two calculation methods gave practically identical results, while for highly cytotoxic compounds, the traditional method overestimated genotoxicity. umuC tests were also carried out on leachate polluted groundwater sampled downgradient of a landfill (Grindsted, Denmark). All polluted samples showed high cytotoxicity concomitant with high genotoxicity when the results were quantified in the traditional way. The new method showed that these results were in fact false positive, as the apparent genotoxicity was a result of cytotoxicity. Based on the mathematical analysis leading to the improved procedure for correction for cytotoxicity, it is suggested to alter the present test design of the umuC test in order to obtain well-defined exposure concentrations as well as mathematical consistency in the quantification of genotoxicity.

4-Nitroquinoline-1-oxide↗