Jan Ahlers - Academia.edu (original) (raw)
Papers by Jan Ahlers
The criteria for classification and labelling of substances as "dangerous for the environmen... more The criteria for classification and labelling of substances as "dangerous for the environment" agreed upon within the European Union (EU) were applied to two sets of existing chemicals. One set (sample A) consisted of 41 randomly selected compounds listed in the European Inventory of Existing Chemical Substances (EINECS). The other set (sample B) comprised 115 substances listed in Annex I of Directive 67/548/EEC which were classified by the EU Working Group on Classification and Labelling of Existing Chemicals. The aquatic toxicity (fish mortality, Daphnia immobihsation, algal growth inhibition), ready biodegradability and n-octanol/water partition coefficient were measured for sample A by one and the same laboratory. For sample B, the available ecotoxicological data originated from many different sources and therefore was rather heterogeneous. In both samples, algal toxicity was the most sensitive effect parameter for most substances. Furthermore, it was found that, class...
Background An Integrated Testing and Assessment Strategy (ITS) for aquatic toxicity of 16 thioche... more Background An Integrated Testing and Assessment Strategy (ITS) for aquatic toxicity of 16 thiochemicals to be registered under REACH revealed 12 data gaps, which had to be filled by experimental data. These test results are now available and offer the unique opportunity to subject previous estimates obtained by read-across (analogue and category approaches) to an external validation. The case study thiochemicals are so-called difficult substances due to instability and poor water solubility, challenging established ITS. Results The new experimental data confirm the previous predictions of acute aquatic toxicity with the new test results indicating a 2-5 times lower toxicity than previously predicted. The previous predictions thus are conservative and closer to the experimental results than expected. The good agreement can be attributed to the fact that we had limited the extrapolations to narrow chemical groups with similar SH-group reactivities. The new experimental data further st...
Zeitschrift für Naturforschung C
The pesticide PCP was shown to inhibit the Hill reaction in broken chloroplasts (I50 = 15 μᴍ) and... more The pesticide PCP was shown to inhibit the Hill reaction in broken chloroplasts (I50 = 15 μᴍ) and to quench chlorophyll fluorescence. Both effects require preillumination. In contrast to the common “phenol-type” inhibitors, neither inhibition of Hill reaction nor chlorophyll fluorescence quench were affected by pretreatment of chloroplast with trypsin instead of preillumination. An inhibition site differing from the “phenol type” inhibitors is therefore assumed. The results presented indicate that the observed light requirement is due to electron transport through PS II. Measurements of intrinsic tryptophane fluorescence relate the PCP site of binding to a hydro- phobic environment.
Chemosphere
REACH requires information on hazardous properties of substances to be generated avoiding animal ... more REACH requires information on hazardous properties of substances to be generated avoiding animal testing where possible. It is the objective of the present case study with thiochemicals to extract as much information as possible from available experimental data with fish, daphnia and algae and to fill data gaps for analogues to be registered under REACH in 2018. Based on considerations of chemical similarity and common mode of action (MOA) the data gaps regarding the aquatic toxicity of the thiochemicals were largely closed by trend analysis ("category approach") and read-across within the same group, for example, thioglycolates or mercaptopropionates. Among 16 thiochemicals to be registered by 2018 there are only 2 substances with sufficient data. 36 data gaps for 14 thiochemicals were identified. Most of the required data (>60%) could be estimated by in silico methods. Only 14 tests (6 algae, 6 daphnia, 1 limit fish test and 1 acute fish test) were proposed. When the results of these tests are available it has to be discussed whether 2 further fish (limit) tests are required. For two substances (exposure-based) waiving was suggested. The relatively high toxicity of the thiochemicals is manifested in low predicted no-effect concentrations (PNECs). Only preliminary predicted environmental concentrations (PECs) could be derived for the thiochemicals for which a risk assessment has to be performed (production rate >10 t/y). The preliminary PEC/PNEC ratios indicate no risk for the aquatic compartment at the production site. PECs due to down-stream use must not exceed the estimated PNECs.
Environmental sciences Europe, 2016
This article gives a comprehensive overview on the strategy, the development and the progress of ... more This article gives a comprehensive overview on the strategy, the development and the progress of the German postgraduate degree program in ecotoxicology (SETAC GLB and GDCh). The program soon prompted positive results: more than 10 years now the courses had an average enrolment rate of 90 %, and employment-seeking graduates from the first courses mostly succeeded in quickly finding employment relevant to their training. With over 450 students enrolled to date, the degree program contributes significantly to the field of Environmental Chemistry and Ecotoxicology.
Umweltwissenschaften Und Schadstoff Forschung, 2004
Umweltwissenschaften Und Schadstoff Forschung, 2004
Umweltwissenschaften Und Schadstoff Forschung, Feb 1, 2009
Umweltwissenschaften Und Schadstoff Forschung, 2001
Umweltwissenschaften Und Schadstoff Forschung, 2000
Umweltwissenschaften und Schadstoff-Forschung, 1995
Umweltwissenschaften und Schadstoff-Forschung, 2006
Umweltwissenschaften und Schadstoff-Forschung, 2004
Einleitung Wenn man das Spektrum der Themen betrachtet, die in der 'UWSF-Umwelrwissenschaft und S... more Einleitung Wenn man das Spektrum der Themen betrachtet, die in der 'UWSF-Umwelrwissenschaft und Schadstoff-Forschung' oder auf einer Jahrestagung der SETAC in VortrSgen und Postern bebandelt werden, wird klar, dass die zukiinftige Entwicklung der Umweltchemie und Okotoxikologie in einem kurzen Editorial nicht umfassend dargestelh werden kann. Ich m6chte deshalb nur einige Gedanken bzw. Wiins.che aus meiner Sicht ~iuf~ern. Aus meiner Sicht bedeutet aus regulatorischer Sicht, von jemandem, dessen Aufgabe darin besteht, Aussagen zu treffen fiber das Risiko von Stoffen in der Umwelt. Die enge Verzahnung von Umweltchemie und Okotoxikologie lassen es als nicht praktikabel erscheinen, beide Richtungen unabh~ingig voneinander zu betrachten. Die kiinftigen Entwicklungen werden stark von den Wechselbeziehungen zwischen Umweltchemie und Okotoxikologie bestimmt werden. Ich werde deshalb in meinen Ausfi~hrungen beide Aspekte zusammen betrachten.
Umweltwissenschaften Und Schadstoff Forschung, 2005
Umweltwissenschaften und Schadstoff-Forschung, 1997
Umweltwissenschaften Und Schadstoff Forschung, 2003
Umweltwissenschaften Und Schadstoff Forschung, 2005
The criteria for classification and labelling of substances as "dangerous for the environmen... more The criteria for classification and labelling of substances as "dangerous for the environment" agreed upon within the European Union (EU) were applied to two sets of existing chemicals. One set (sample A) consisted of 41 randomly selected compounds listed in the European Inventory of Existing Chemical Substances (EINECS). The other set (sample B) comprised 115 substances listed in Annex I of Directive 67/548/EEC which were classified by the EU Working Group on Classification and Labelling of Existing Chemicals. The aquatic toxicity (fish mortality, Daphnia immobihsation, algal growth inhibition), ready biodegradability and n-octanol/water partition coefficient were measured for sample A by one and the same laboratory. For sample B, the available ecotoxicological data originated from many different sources and therefore was rather heterogeneous. In both samples, algal toxicity was the most sensitive effect parameter for most substances. Furthermore, it was found that, class...
Background An Integrated Testing and Assessment Strategy (ITS) for aquatic toxicity of 16 thioche... more Background An Integrated Testing and Assessment Strategy (ITS) for aquatic toxicity of 16 thiochemicals to be registered under REACH revealed 12 data gaps, which had to be filled by experimental data. These test results are now available and offer the unique opportunity to subject previous estimates obtained by read-across (analogue and category approaches) to an external validation. The case study thiochemicals are so-called difficult substances due to instability and poor water solubility, challenging established ITS. Results The new experimental data confirm the previous predictions of acute aquatic toxicity with the new test results indicating a 2-5 times lower toxicity than previously predicted. The previous predictions thus are conservative and closer to the experimental results than expected. The good agreement can be attributed to the fact that we had limited the extrapolations to narrow chemical groups with similar SH-group reactivities. The new experimental data further st...
Zeitschrift für Naturforschung C
The pesticide PCP was shown to inhibit the Hill reaction in broken chloroplasts (I50 = 15 μᴍ) and... more The pesticide PCP was shown to inhibit the Hill reaction in broken chloroplasts (I50 = 15 μᴍ) and to quench chlorophyll fluorescence. Both effects require preillumination. In contrast to the common “phenol-type” inhibitors, neither inhibition of Hill reaction nor chlorophyll fluorescence quench were affected by pretreatment of chloroplast with trypsin instead of preillumination. An inhibition site differing from the “phenol type” inhibitors is therefore assumed. The results presented indicate that the observed light requirement is due to electron transport through PS II. Measurements of intrinsic tryptophane fluorescence relate the PCP site of binding to a hydro- phobic environment.
Chemosphere
REACH requires information on hazardous properties of substances to be generated avoiding animal ... more REACH requires information on hazardous properties of substances to be generated avoiding animal testing where possible. It is the objective of the present case study with thiochemicals to extract as much information as possible from available experimental data with fish, daphnia and algae and to fill data gaps for analogues to be registered under REACH in 2018. Based on considerations of chemical similarity and common mode of action (MOA) the data gaps regarding the aquatic toxicity of the thiochemicals were largely closed by trend analysis ("category approach") and read-across within the same group, for example, thioglycolates or mercaptopropionates. Among 16 thiochemicals to be registered by 2018 there are only 2 substances with sufficient data. 36 data gaps for 14 thiochemicals were identified. Most of the required data (>60%) could be estimated by in silico methods. Only 14 tests (6 algae, 6 daphnia, 1 limit fish test and 1 acute fish test) were proposed. When the results of these tests are available it has to be discussed whether 2 further fish (limit) tests are required. For two substances (exposure-based) waiving was suggested. The relatively high toxicity of the thiochemicals is manifested in low predicted no-effect concentrations (PNECs). Only preliminary predicted environmental concentrations (PECs) could be derived for the thiochemicals for which a risk assessment has to be performed (production rate >10 t/y). The preliminary PEC/PNEC ratios indicate no risk for the aquatic compartment at the production site. PECs due to down-stream use must not exceed the estimated PNECs.
Environmental sciences Europe, 2016
This article gives a comprehensive overview on the strategy, the development and the progress of ... more This article gives a comprehensive overview on the strategy, the development and the progress of the German postgraduate degree program in ecotoxicology (SETAC GLB and GDCh). The program soon prompted positive results: more than 10 years now the courses had an average enrolment rate of 90 %, and employment-seeking graduates from the first courses mostly succeeded in quickly finding employment relevant to their training. With over 450 students enrolled to date, the degree program contributes significantly to the field of Environmental Chemistry and Ecotoxicology.
Umweltwissenschaften Und Schadstoff Forschung, 2004
Umweltwissenschaften Und Schadstoff Forschung, 2004
Umweltwissenschaften Und Schadstoff Forschung, Feb 1, 2009
Umweltwissenschaften Und Schadstoff Forschung, 2001
Umweltwissenschaften Und Schadstoff Forschung, 2000
Umweltwissenschaften und Schadstoff-Forschung, 1995
Umweltwissenschaften und Schadstoff-Forschung, 2006
Umweltwissenschaften und Schadstoff-Forschung, 2004
Einleitung Wenn man das Spektrum der Themen betrachtet, die in der 'UWSF-Umwelrwissenschaft und S... more Einleitung Wenn man das Spektrum der Themen betrachtet, die in der 'UWSF-Umwelrwissenschaft und Schadstoff-Forschung' oder auf einer Jahrestagung der SETAC in VortrSgen und Postern bebandelt werden, wird klar, dass die zukiinftige Entwicklung der Umweltchemie und Okotoxikologie in einem kurzen Editorial nicht umfassend dargestelh werden kann. Ich m6chte deshalb nur einige Gedanken bzw. Wiins.che aus meiner Sicht ~iuf~ern. Aus meiner Sicht bedeutet aus regulatorischer Sicht, von jemandem, dessen Aufgabe darin besteht, Aussagen zu treffen fiber das Risiko von Stoffen in der Umwelt. Die enge Verzahnung von Umweltchemie und Okotoxikologie lassen es als nicht praktikabel erscheinen, beide Richtungen unabh~ingig voneinander zu betrachten. Die kiinftigen Entwicklungen werden stark von den Wechselbeziehungen zwischen Umweltchemie und Okotoxikologie bestimmt werden. Ich werde deshalb in meinen Ausfi~hrungen beide Aspekte zusammen betrachten.
Umweltwissenschaften Und Schadstoff Forschung, 2005
Umweltwissenschaften und Schadstoff-Forschung, 1997
Umweltwissenschaften Und Schadstoff Forschung, 2003
Umweltwissenschaften Und Schadstoff Forschung, 2005