| 1. |
- Brunström, Björn, et al.
(författare)
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EROD induction in cultured chick embryo liver : a sensitive bioassay for dioxin-like environmental pollutants
- 1995
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 14:5, s. 837-842
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Tidskriftsartikel (refereegranskat)abstract
- A technique for studying 7-ethoxyresorufin O-deethylase (EROD) induction in chick embryo liver in vitro was developed. Livers from 8-d-old embryos were cultured in rotating vials at 37 degrees C for 48 h in a medium to which DMSO-dissolved test compounds had been added. This bioassay proved to be highly sensitive to dioxin-like compounds, and its usefulness for assessing the toxic potency of such compounds in environmental samples was demonstrated. Concentration-response curves were determined for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4',5-penlachlorobiphenyl (PCB IUPAC no. 126), 3,3',4,4'-tetrachlorobiphenyl (PCB 77), 2,3,3',4,4'-pentachlorobiphenyl (PCB 105), and benzo[k]fluoranthene (BkF). TCDD induced EROD in a concentration-dependent manner, having an EC50 of 5.0 x 10(-12) M. The cultured embryo livers were extremely sensitive to TCDD, and about 30 fg of this compound per liver (2 x 10(-13) M) was enough to significantly induce EROD. The EC50 values obtained for PCBs 126, 77, 105, and BkF were 4,4 x 10(-11) M, 9.2 x 10(-9) M, 1.6 x 10(-8) M, and 6.2 x 10(-7) M, respectively. The maximal induction levels obtained for three different preparations of polychlorinated naphthalenes (PCNs) were less than those of the other compounds tested. When the technical PCN mixture Halowax 1014 was coadministered with TCDD, the induction was lower than that caused by TCDD alone. An organic extract of fly ash from a municipal waste combustion plant was very potent. Considering its contents of polychlorinated dibenzo-p-dioxins/furans, expressed as TCDD equivalents, the EC50 obtained was close to that for TCDD.
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| 2. |
- Engwall, Magnus, 1965-, et al.
(författare)
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Biological and chemical determination of contaminant levels in settling particulate matter and sediments : a Swedish river system before, during, and after dredging of PCB-contaminated lake sediments
- 1998
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Ingår i: Ambio. - 0044-7447 .- 1654-7209. ; 27:5, s. 403-410
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive bioassay, based on EROD induction in cultured chicken embryo livers, was used together with chemical analysis to determine levels of dioxin-like contaminants in particulate matter in Eman. Extracts of sediment and settling particulate matter (SPM) collected in the river system before, during, and after dredging of a PCB contaminated lake, Lake Jarnsjon, were separated into three fractions containing a) monoaromatic/aliphatic; b) diaromatic (e.g., PCBs and polychlorinated dibenzodioxins and dibenzofurans); and c) polyaromatic compounds (e.g., polycyclic aromatic hydrocarbons). The samples from Lake Jarnsjon contained the highest PCB concentrations and the diaromatic extracts from Lake Jarnsjon samples showed the highest activities of EROD-inducing diaromatic compounds. The dioxin-like activity of the diaromatic fraction in sediment collected after the dredging of Jarnsjon had only around 1% of the activity of the pre-dredging sediment, showing that the remediation was successful in terms of removal of the PCB-contaminated sediment from the lake. In SPM collected immediately downstream from Jarnsjon, levels of diaromatic dioxin-like compounds were elevated during the dredging, and decreased after that. The post-dredging concentrations were however higher than in SPM from lakes upstream of Jarnsjon, showing that elevated levels of dioxin-like diaromatic compounds were still present in the water System downstream of Jarnsjon a couple of years after the dredging.
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| 3. |
- Engwall, Magnus, 1965-, et al.
(författare)
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Dioxin-like compounds in HPLC-fractionated extracts of marine samples from the east and west coast of Sweden : bioassay- and instrumentally-derived TCDD equivalents
- 1997
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Ingår i: Marine Pollution Bulletin. - 0025-326X .- 1879-3363. ; 34:12, s. 1032-1040
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Tidskriftsartikel (refereegranskat)abstract
- Lipophilic extracts of sediment, settling particulate matter (SPM) and blue mussel (Mytilus edulis) samples, collected at coastal locations on the east and west coast of Sweden, were HPLC-separated into three fractions containing 1. monoaromatic/aliphatic, 2. diaromatic (e,g, polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins and polychlorinated dibenzofuraus (PCDDs/Fs)), and 3, polyaromatic compounds (e,g, polycyclic aromatic hydrocarbons (PAHs)), The fractions were tested for dioxin-like effects using a sensitive bioassay, based on EROD-induction in cultured chicken embryo livers, The concentrations of PCDDs/Fs, PCBs and 15 PAHs in the samples were also determined, The polyaromatic fractions of the sediment samples were more potent as EROD-inducers than the diaromatic fractions, Only a small part of the EROD-induction caused by the polyaromatic fractions could be explained by the analysed PAHs in the samples, indicating presence of non-quantified polyaromatic EROD-inducing compounds in the samples, A greater pollution by EROD-inducing diaromatic and polyaromatic compounds on the east coast site than on the west coast site was seen, The filtration activities and faeces production of the mussels on the east coast experimental site increased the sedimentation of PCDDs/Fs, PCBs and PAHs, The described bioassay proved very useful in the assessment of dioxin-like compounds in both abiotic and biotic samples from the marine environment,
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| 4. |
- Engwall, Magnus, 1965-, et al.
(författare)
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Levels of dioxin-like compounds in sewage sludge determined with a bioassay based on EROD induction in chicken embryo liver cultures
- 1999
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Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 38:10, s. 2327-2343
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Tidskriftsartikel (refereegranskat)abstract
- A bioassay for the detection of dioxin-like compounds was used to estimate levels in sewage sludge from Swedish sewage treatment plants (STPs). The sludge extracts were HPLC-separated into three fractions containing a) monoaromatic/aliphatic, b) diaromatic (e.g. polychlorinated biphenyls [PCBs], polychlorinated dibenzodioxins and polychlorinated dibenzofurans [PCDDs/Fs]), and c) polyaromatic compounds (e.g. polycyclic aromatic hydrocarbons [PAHs]). The bioassay, which is based on EROD (7-ethoxyresorufin O-deethylase) induction in cultured chicken embryo livers detected dioxin-like activity in all unfractionated extracts and in the di- and polyaromatic fractions of all sludge extracts, but not in the monoatomatic/aliphatic fractions. The levels ranged between 6 and 109 pg bio-TEQ/g sludge (d.w.). In sediment samples from rural lakes in Sweden, levels of about 5 pg bio-TEQ/g (d.w.) have been found. The polyaromatic fractions of the sludge samples were potent in the bioassay, probably due to various PAHs and other polyaromatics in the sludge. The levels of six PAHs that are screened for in the sludge at Swedish STPs accounted for only 3-10% of the observed EROD-induction by the polyaromatic fractions. Consequently, many other polyaromatic EROD-inducing compounds were present in the sludge. Inclusion of a biological test like the chicken embryo liver bioassay in the screening of sludge would improve the ability to detect the presence of bioactive dioxin-like compounds. A theoretical estimation of bio-TEQ concentrations in farm-soil following long-term application of sludge with bio-TEQ concentrations similar to those observed in this investigation indicated that the bio-TEQ levels in soil would increase very slowly over time. The chicken embryo liver bioassay proved useful in assessing levels of dioxin-like compounds in sewage sludge and it gives valuable complementary information to chemical analysis data.
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| 5. |
- Engwall, Magnus, 1965-, et al.
(författare)
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Toxic potencies of extracts of sediment and settling particulate matter collected in the recipient of a bleached pulp mill effluent before and after abandoning chlorine bleaching
- 1997
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 16:6, s. 1187-1194
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Tidskriftsartikel (refereegranskat)abstract
- Extracts of bottom sediment and settling particulate matter (SPM) samples collected in the recipient water body of a bleached pulp mill effluent were separated into three fractions: monoaromatic/aliphatic compounds, diaromatic compounds (e.g., polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans), and polyaromatic compounds assessment of dioxinlike potency were an in vitro assay, based on the induction of 7-ethoxyresorufin-O-deethylase (EROD) in chicken embryo livers, a test for EROD induction in ovo using chicken embryos, and an immunotoxicity test measuring inhibition of lymphoid cell development in cultured fetal mouse thymuses. The samples collected closest to the mill were the most potent. There was a time-dependent decrease in dioxinlike potency in the SPM samples collected near the mill, which coincided with the cessation of chlorine gas bleaching at the mill. The bioassays in general, and the in vitro chicken embryo liver bioassay in particular, proved useful in the assessment of dioxinlike compounds in the sediment and SPM samples. The polyaromatic fractions of the samples were generally more potent than the diaromatic fractions. Only a small part of the effects caused by the polyaromatic fractions could be explained by 15 analyzed PAHs, indicating the presence of unquantified polyaromatic compounds with dioxinlike effects. This investigation indicates that the cessation of chlorine bleaching in the pulp mill resulted in a reduced load of diaromatic dioxinlike compounds in the recipient water body.
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| 6. |
- Engwall, Magnus, 1965-, et al.
(författare)
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Toxic potencies of lipophilic extracts from sediments and settling particulate matter (SPM) collected in a PCB-contaminated river system
- 1996
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 15:2, s. 213-222
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Tidskriftsartikel (refereegranskat)abstract
- Sediments and settling particulate matter (SPM) were sampled in a polychlorinated biphenyl (PCB)-contaminated lake, Lake Jarnsjon, and in lakes located up-/and downstream from Lake Jarnsjon. The 7-ethoxyresorufin O-deethylase (EROD)-inducing potencies of lipophilic extracts from sediment and SPM were investigated in organ cultures of chicken embryo livers (denoted in vitro chicken embryo liver bioassay). The extract from sediments collected in Lake Jarnsjon had the greatest EROD-inducing potency of the extracts studied, and it also contained the highest concentrations of PCBs, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated dibenzodioxins/furans (PCDDs/Fs). The non-ortho-chlorinated PCBs in the extracts were probably major contributors to the EROD induction noted. The EROD-inducing potency of sediment extract from the lake downstream Lake Jarnsjon was higher than that of extract from the upstream lake. This indicates that EROD-inducing substances were transported from Lake Jarnsjon sediment to the lake downstream. The extracts from Lake Jarnsjon sediment and SPM were separated into three fractions containing aliphatic/monoaromatic, diaromatic, and polyaromatic compounds, respectively, which were tested in the in vitro chicken embryo Liver bioassay. In all extracts, the aliphatic/monoaromatic fractions were low in EROD-inducing potency, while the polyaromatic fractions from SPM were more potent than their corresponding diaromatic fractions, indicating that they contained high concentrations of aromatic hydrocarbon (Ah) receptor ligands. Only a small part of the EROD induction caused by the polyaromatic fractions could be attributed to the 15 analyzed PAHs in the samples. The EROD-inducing potencies of the diaromatic fractions correlated quite well with their concentrations of PCDDs/Fs and PCBs. The in vitro chicken embryo liver bioassay detected low concentrations of EROD inducers in the extracts and therefore proved useful for estimating the contents of Ah receptor ligands in environmental samples.
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