natgillin/translations-raw huggingface dataset:
Undersøgelser har vist, at sådanne resultater fås, når det aktiverede slam, der bruges i testen, nitrificerer i betydelig grad, og testkemikaliet har større virkning på iltningen af ammonium end på den generelle heterotrofe iltning.
The system is distributed or homogenous and the biomass can be viewed as a continuum without consideration of individual cells.
Disse falske resultater kan derfor afhjælpes ved yderligere testning med en specifik nitrifikationshæmmer.
The variance distribution of the type of response for a such system relate solely to experimental factors (described typically by the log-normal or normal distributions of error).
Ved at måle iltoptagelseshastigheden med og uden en sådan hæmmer, f.eks. N-allylthiourinstof (ATU), kan de enkelte samlede iltoptagelseshastigheder ved henholdsvis heterotrof iltning og nitrifikation beregnes (4)(7)(8).
This is by contrast to typical bioassay responses with quantal data for which the tolerance (typically binomially distributed) of individual organisms are often assumed to be the dominant variance component.
Et testkemikalies hæmmende virkninger på de to processer kan således bestemmes, og EC50-værdierne for både iltning af organisk kulstof (heterotrof) og ammoniumiltning (nitrifikation) kan beregnes på sædvanlig vis.
Control responses are here zero or background level.
Det skal bemærkes, at N-allylthiourinstofs hæmmende virkning i sjældne tilfælde kan ophæves helt eller delvist som følge af kompleksdannelse med testkemikalier eller tilsat substrat, f.eks. Cu++-ioner (6).
In the uncomplicated situation, the normalised or relative response, r, decreases monotonically from 1 (zero inhibition) to 0 (100 per cent inhibition).
Cu++-ioner er af afgørende betydning for Nitrosomonas, men er toksiske i højere koncentrationer.
Note, that all responses have an error associated and that apparent negative inhibitions can be calculated as a result of random error only.
Der er opstået et presserende behov for nitrifikation i den aerobe behandling af spildevand i europæiske lande som et nødvendigt trin i fjernelsen af kvælstofforbindelser fra spildevand ved denitrifikation til gasformige produkter;
Regression analysis
EU har nu fastsat nedre grænser for koncentrationen af kvælstof i behandlet spildevand, der udledes til modtagende vand [2].
Models
Metoden til vurdering af virkningen på iltning af organisk kulstof er tilstrækkelig til de fleste formål.
A regression analysis aims at quantitatively describing the concentration response curve in the form of a mathematical regression function Y = f (C) or more frequently F(Z) where Z = log C. Used inversely C = f– 1 (Y) allows the calculation of, ECx figures, including the EC50, EC10 and EC20, and their 95 % confidence limits.
I visse tilfælde er det dog nødvendigt med en undersøgelse af virkningen på nitrifikation alene, eller på både nitrifikation og iltning af organisk kulstof hver for sig, for at kunne fortolke resultaterne og forstå virkningerne.
Several simple mathematical functional forms have proved to successfully describe concentration — response relationships obtained in algal growth inhibition tests.
TESTMETODENS PRINCIP
Functions include for instance the logistic equation, the nonsymmetrical Weibul equation and the log normal distribution function, which are all sigmoid curves asymptotically approaching zero for C → 0 and one for C → infinity.
Respirationshastigheden for prøver af aktiveret slam tilført syntetisk spildevand måles i en indkapslet celle, der indeholder en iltelektrode, efter en kontakttid på tre timer.
The use of continuous threshold function models (e.g. the Kooijman model “for inhibition of population growth” Kooijman et al.
Længere kontakttider kan være hensigtsmæssige for at opnå et realistisk eksponeringsscenarie.
1996) is a recently proposed or alternative to asymptotic models.
Hvis testkemikaliet er hurtigt nedbrydeligt, f.eks. abiotisk ved hydrolyse, eller er flygtigt, og koncentrationen ikke kan opretholdes i tilstrækkelig grad, kan der desuden anvendes en kortere eksponeringsperiode, f.eks. 30 minutter.
This model assumes no effects at concentrations below a certain threshold EC0+ that is estimated by extrapolation of the response concentration relationship to intercept the concentration axis using a simple continuous function that is not differentiable in the starting point.
Følsomheden af hvert parti aktiveret slam bør kontrolleres med et passende referencekemikalie på eksponeringsdagen.
Note that the analysis can be a simple minimisation of sums of residual squares (assuming constant variance) or weighted squares if variance heterogeneity is compensated.
Testen bruges typisk til at bestemme testkemikaliets ECx (f.eks. EC50) og/eller koncentrationen uden observeret effekt (NOEC).
Procedure
Hæmningen af iltoptagelsen i mikroorganismer, der ilter organisk kulstof, kan udtrykkes særskilt fra iltoptagelsen i mikroorganismer, der ilter ammonium, ved måling af iltoptagelseshastigheden med og uden N-allylthiourinstof, som er en specifik inhibitor af de nitrificerende bakteriers iltning af ammonium til nitrit i første fase.
The procedure can be outlined as follows:
I dette tilfælde beregnes hæmningen i procent af iltoptagelseshastigheden ved sammenligning af iltoptagelseshastigheden med et testkemikalie med den gennemsnitlige iltoptagelseshastighed for de tilsvarende kontroller, der ikke indeholder noget testkemikalie, både med og uden den specifikke inhibitor, N-allylthiourinstof.
Select an appropriate functional equation, Y = f(C), and fit it to the data by non-linear regression.
Iltoptagelse som følge af abiotiske processer kan påvises ved at bestemme hastigheden i blandinger af testkemikalie, syntetisk spildevandssubstrat og vand, idet aktiveret slam udelades.
Use preferably the measurements from each individual flask rather than means of replicates, in order to extract as much information from the data as possible.
OPLYSNINGER OM TESTKEMIKALIET
If the variance is high, on the other hand, practical experience suggests that means of replicates may provide a more robust mathematical estimation less influenced by systematic errors in the data, than with each individual data point retained.
Testkemikaliets identifikation (fortrinsvis CAS-nummer), navn (IUPAC), renhed, vandopløselighed, damptryk, flygtighed og adsorptionsegenskaber skal være kendt, for at resultaterne kan fortolkes korrekt.
Plot the fitted curve and the measured data and examine whether the curve fit is appropriate.
Normalt kan flygtige kemikalier ikke testes korrekt, medmindre der træffes særlige forholdsregler (se punkt 21).
Analysis of residuals may be a particular helpful tool for this purpose.
TESTMETODENS ANVENDELIGHED
If the chosen functional relationship to fit the concentration response does not describe well the whole curve or some essential part of it, such as the response at low concentrations, choose another curve fit option — e.g., a non-symmetrical curve like the Weibul function instead of a symmetrical one.
Testmetoden kan anvendes på vandopløselige, tungt opløselige og flygtige kemikalier.
Negative inhibitions may be a problem with for instance the log — normal distribution function likewise demanding an alternative regression function.
Der er dog ikke altid muligt at opnå EC50-værdier med kemikalier med begrænset opløselighed, og der kan kun opnås gyldige resultater med flygtige kemikalier, hvis størstedelen (> 80 %) af testkemikaliet er til stede i reaktionsblandingen ved udløbet af eksponeringsperioden/-perioderne.
It is not recommended to assign a zero or small positive value to such negative values because this distorts the error distribution.
Yderligere analytiske støttedata skal forelægges for at præcisere ECx-koncentrationen, når der er usikkerhed om testkemikaliets stabilitet eller flygtighed.
It may be appropriate to make separate curve fits on parts of the curve such as the low inhibition part to estimate EClowx figures.
REFERENCEKEMIKALIER
Calculate from the fitted equation (by “inverse estimation”, C = f– 1(Y)), characteristic point estimates ECx's, and report as a minimum the EC50 and one or two EClow x estimates.
Referencekemikalier skal testes periodisk, for at sikre at testmetoden og -betingelserne er pålidelige, og for at kontrollere følsomheden af hvert parti aktiveret slam, der er brugt som mikrobielt inokulum på eksponeringsdagen.
Experience from practical testing has shown that the precision of the algal test normally allows a reasonably accurate estimation at the 10 % inhibition level if data points are sufficient — unless stimulation occurs at low concentrations as a confounding factor.
Kemikaliet 3,5-dichlorphenol (3,5-DCP) anbefales som hæmmende referencekemikalie, da det vides at hæmme respiration og bruges i mange typer hæmnings-/toksicitetstest (4).
The precision of an EC20 estimate is often considerably better than that of an EC10, because the EC20 is usually positioned on the approximately linear part of the central concentration response curve.
N-methylanilin kan bruges som specifik nitrifikationshæmmer (4).
So while the EC10 is normally obtainable with a sufficient accuracy it is recommended to report always also the EC20.
VALIDITETSKRITERIER OG REPRODUCERBARHED
Weighting factors
Iltoptagelseshastigheden for blindkontrollerne (uden testkemikalie eller referencekemikalie) må ikke være under 20 mg ilt pr. gram aktiveret slam (tørvægt af opslæmmet faststof) pr. time.
The experimental variance generally is not constant and typically includes a proportional component, and a weighted regression is therefore advantageously carried out routinely.
Hvis hastigheden er lavere, skal testen gentages med vasket aktiveret slam eller med slam fra en anden kilde.
Weighting factors for a such analysis are normally assumed inversely proportional to the variance:
Variationskoefficienten for iltoptagelseshastigheden i kontrolreplikater må ikke overstige 30 % ved den endelige tests afslutning.
Many regression programs allow the option of weighted regression analysis with weighting factors listed in a table.
I den internationale ringtest, der blev tilrettelagt af ISO (4) i 2004, og hvor der blev anvendt aktiveret slam fremstillet af husholdningsspildevand, viste EC50 for 3,5-DCP sig at ligge i intervallet 2 mg/l til 25 mg/l for samlet respiration, 5 mg/l til 40 mg/l for heterotrof respiration og 0,1 mg/l til 10 mg/l for respiration ved nitrifikation.
Conveniently weighting factors should be normalised by multiplying them by n/Σ wi (n is the number of datapoints) so their sum be one.
Hvis EC50 for 3,5-DCP ikke ligger i det forventede område, skal testen gentages med aktiveret slam fra en anden kilde.
Normalising responses
for kobber-(II)-sulfatpentahydrat bør ligge i området 53-155 mg/l for den samlede respiration (9).
Normalising by the mean control response gives some principle problems and gives rise to a rather complicated variance structure.
Testbeholdere og -apparatur
Dividing the responses by the mean control response for obtaining the percentage of inhibition, one introduces an additional error caused by the error on the control mean.
Der skal anvendes sædvanligt laboratorieudstyr og følgende udstyr:
Unless this error is negligibly small, weighting factors in the regression and confidence limits must be corrected for the covariance with the control (Draper and Smith, 1981).
Testbeholdere — f.eks. 1000 ml bægerglas, som skal indeholde 500 ml reaktionsblanding (se 5 i figur 1)
Note that high precision on the estimated mean control response is important in order to minimise the overall variance for the relative response.
alternativt kan der bruges en BOD-kolbe med en passende muffeadapter til forsegling af iltelektroden på kolbens hals (se figur 2 i tillæg 3).
This variance is as follows:
For at forhindre tab af væske, der fortrænges, når iltelektroden indsættes, tilrådes det først at indsætte en tragt eller et glasrør gennem muffen eller bruge beholdere med tragtformet åbning.
(Subscript i refers to concentration level i and subscript 0 to the controls)
I begge tilfælde bør der anvendes en magnetomrører eller en anden omrøringsmetode, f.eks. en selvomrørende sonde
Yi = Relative response = ri/r0 = 1 – I = f(Ci)
Magnetomrørere og stangmagneter, som er overtrukket med inert materiale, til brug i målekammeret og/eller testbeholderne
with a variance Var(Yi) = Var (ri/r0) ≅ (∂ Yi/∂ ri) · Var(ri) + ((∂ Yi/∂ r0)2 · Var(r0)
Beluftningsapparatur:
and since (∂ Yi/∂ ri) = 1/r0 and (∂ Y I/∂ r0) = ri/r02
Komprimeret luft ledes om nødvendigt gennem et passende filter for at fjerne støv og olie og gennem vaskeflasker, der indeholder vand, for at fugte luften.
with normally distributed data and mi and m0 replicates:
Beholderens indhold bør beluftes med pasteurpipetter eller beluftningsapparater, der ikke adsorberer kemikalier.
Var(ri) = σ2/mi
En orbitalryster, der kører med orbitale hastigheder på mellem 150 og 250 omdr./min., med kolber med en kapacitet på f.eks. 2000 ml kan bruges til at dække slammets iltforbrug og løse problemer med kemikalier, der frembringer stærk skumning, er flygtige og derfor går tabt eller er vanskeligt dispergerbare, når de beluftes ved luftgennembobling.
the total variance of the relative response Yi thus becomes
Der kan også anvendes validerede instrumenter, der giver mulighed for samtidig beluftning og måling af iltforbrugshastigheden i blandingerne
An alternative procedure is not to normalise the data and fit the absolute responses including the control response data but introducing the control response value as an additional parameter to be fitted by non linear regression.
pH-meter
With a usual 2 parameter regression equation, this method necessitates the fitting of 3 parameters, and therefore demands more data points than non-linear regression on data that are normalised using a pre-set control response.
Centrifuge, almindelig bordcentrifuge til slam med en kapacitet på 10000 m/s2.
Inverse confidence intervals
Reagenser
The calculation of non-linear regression confidence intervals by inverse estimation is rather complex and not an available standard option in ordinary statistical computer program packages.
Der bør anvendes reagenser af analysekvalitet i hele testen.
Approximate confidence limits may be obtained with standard non-linear regression programs with re-parameterisation (Bruce and Versteeg, 1992), which involves rewriting the mathematical equation with the desired point estimates, e.g. the EC10 and the EC50 as the parameters to be estimated.
Vand
(Let the function be I = f (α, β, Concentration) and utilise the definition relationships f (α, β, EC10) = 0,1 and f (α, β, EC50 ) = 0,5 to substitute f (α, β, concentration ) with an equivalent function g( EC10, EC50, concentration).
Der bør kun bruges destilleret eller deioniseret vand, som indeholder under 1 mg/l opløst organisk kulstof, medmindre ledningsvand uden chlor er specificeret.
A more direct calculation (Andersen et al, 1998) is performed by retaining the original equation and using a Taylor expansion around the means of ri and r0.
Syntetisk spildevand
Recently “boot strap methods” have become popular.
Substratet skal fremstilles således, at det indeholder følgende bestanddele i de angivne mængder:
Such methods use the measured data and a random number generator directed frequent re-sampling to estimate an empirical variance distribution.
pepton
REFERENCES
kødekstrakt (eller et sammenligneligt planteekstrakt)
Chapter C.11 is replaced by the following:
urinstof
ACTIVATED SLUDGE, RESPIRATION INHIBITION TEST (CARBON AND AMMONIUM OXIDATION)
natriumchlorid (NaCl)
This test method is equivalent to OECD test guideline (TG) 209 (2010).
calciumchloriddihydrat (CaCl2, 2H2O)
This test method describes a method to determine the effects of a chemical on micro-organisms from activated sludge (largely bacteria) by measuring their respiration rate (carbon and/or ammonium oxidation) under defined conditions in the presence of different concentrations of the test chemical.
magnesiumsulfatheptahydrat (MgSO4, 7H2O)
The test method is based on the ETAD (Ecological and Toxicological Association of the Dyestuffs Manufacturing industry) test (1) ( 2), on the previous OECD TG 209 (3) and on the revised ISO Standard 8192 (4).
dikaliummonohydrogenphosphat (K2HPO4)
The purpose of the test is to provide a rapid screening method to assess the effects of chemicals on the microorganisms of the activated sludge of the biological (aerobic) stage of waste-water treatment plants.
destilleret eller deioniseret vand til 1 liter
The results of the test may also serve as an indicator of suitable non-inhibitory concentrations of test chemicals to be used in biodegradability tests (for example Chapters C.4 A-F, C.9, C.10, C12 and C.29 of this Annex, OECD TG302C).
Denne opløsnings pH skal være 7,5 ± 0,5.
In this case, the test can be performed as a screening test, similar to a range-finding or limit test (see paragraph 39), considering the overall respiration only.
Hvis det fremstillede substrat ikke anvendes straks, skal det opbevares i mørke ved 0 til 4 °C, dog ikke længere end en uge og under forhold, som ikke ændrer sammensætningen.
However, this information should be taken with care for ready biodegradability tests (Chapter C.4 A-F and C.29 of this Annex) for which the inoculum concentration is significantly lower than the one used in this test method.
Det skal bemærkes, at dette syntetiske spildevand er 100 gange så koncentreret som det, der er beskrevet i OECD Technical Report »Proposed method for the determination of the biodegradability of surfactants used in synthetic detergents«, 11. juni 1976, med tilsætning af dikaliumhydrogenphosphat.
Indeed, an absence of inhibition in this respiration test does not automatically result in non-inhibitory conditions in the ready biodegradability test of Chapters C.4 A-F or C.29 of this Annex.
Alternativt kan substratets komponenter steriliseres særskilt forud for opbevaringen, eller der kan tilsættes pepton og kødekstrakt, kort tid før testen udføres.
Overall, the respiration inhibition test seems to have been applied successfully since it was first published, but on some occasions spurious results were reported, e.g. (2) (4) (5).
Substratet skal blandes grundigt inden brug, og pH skal om nødvendigt justeres til pH 7,5 ± 0,5.
Concentration related respiration curves are sometimes bi-phasic, dose-response plots have been distorted and EC50 values have been unexpectedly low (5).
Testkemikalie
Investigations showed that such results are obtained when the activated sludge used in the test nitrifies significantly and the test chemical has a greater effect on the oxidation of ammonium than on general heterotrophic oxidation.
Der skal fremstilles en stamopløsning til de let vandopløselige teststoffer, dog kun op til den maksimale vandopløselighed (udfældning accepteres ikke).
Therefore, these spurious results may be overcome by performing additional testing using a specific inhibitor of nitrification.
Stoffer med ringe vandopløselighed, blandinger med komponenter med forskellig vandopløselighed og adsorptive stoffer skal afvejes direkte i testbeholderne.
By measuring the oxygen uptake rates in the presence and absence of such an inhibitor, e.g. N-allylthiourea (ATU), the separate total, heterotrophic and nitrification oxygen uptake rates can be calculated (4) (7) (8).
I disse tilfælde kan brug af stamopløsninger være et alternativ, hvis opløste koncentrationer af testkemikalierne bestemmes analytisk i testbeholderne (inden tilsætning af aktiveret slam).
Thus, the inhibitory effects of a test chemical on the two processes may be determined and the EC50 values for both organic carbon oxidation (heterotrophic) and ammonium oxidation (nitrification) may be calculated in the usual way.
Hvis der fremstilles Water Accommodated Fractions (WAF — den andel af stoffet, der opløses i vandet), er det desuden afgørende at foretage en analytisk bestemmelse af de opløste koncentrationer af testkemikalierne i testbeholderne.
It should be noted that in some rare cases, the inhibitory effect of N-allylthiourea may be partially or completely nullified as a result of complexation with test chemicals or medium supplements, e.g. Cu++ ions (6).
Det bør undgås at bruge organiske opløsningsmidler og dispergeringsmidler/emulgatorer for at forbedre opløseligheden.
Cu++ ions are essential for Nitrosomonas, but are toxic in higher concentration.
Sonikering af stamopløsninger og suspensioner inden omrøring, f.eks. natten over, er mulig, når der foreligger tilstrækkelige oplysninger om testkemikaliets stabilitet under sådanne betingelser.
The need for nitrification in the aerobic treatment of wastewaters, as a necessary step in the process of removing nitrogen compounds from wastewaters by denitrification to gaseous products, has become urgent particularly in European countries;
Testkemikaliet kan have skadelig indvirkning på pH i testsystemet.
the EU has now set lower limits for the concentration of nitrogen in treated effluents discharged to receiving waters [2].
De testkemikaliebehandlede blandingers pH skal bestemmes inden forsøgsopsætningen i et indledende forsøg, for at konstatere om det er nødvendigt at justere pH inden den endelige test og igen på dagen for den endelige test.
For most purposes, the method to assess the effect on organic carbon oxidation processes alone is adequate.
Opløsninger/suspensioner af testkemikalie i vand bør om nødvendigt neutraliseres inden tilsætning af inokulum.
However, in some cases an examination of the effect on nitrification alone, or on both nitrification and organic carbon oxidation separately, are needed for the interpretation of the results and understanding the effects.
Eftersom neutralisering kan ændre kemikaliets kemiske egenskaber, kan der dog, afhængigt af undersøgelsens formål, foretages yderligere test for at vurdere testkemikaliets virkning på slammet uden pH-justering.
PRINCIPLE OF THE TEST METHOD
Flygtige kemikaliers toksiske virkning, navnlig i test, hvor systemet gennembobles, kan give forskellige effektniveauer, der forekommer som følge af tab af stof i eksponeringsperioden.
The respiration rates of samples of activated sludge fed with synthetic sewage are measured in an enclosed cell containing an oxygen electrode after a contact time of 3 hours.
Der bør udvises forsigtighed med sådanne stoffer ved at foretage stofspecifikke analyser af kontrolblandinger, som indeholder stoffet, og ændre beluftningssystemet.
Under consideration of the realistic exposure scenario, longer contact times could be appropriate.
Referencekemikalie
If the test chemical is rapidly degraded e.g. abiotically via hydrolysis, or is volatile and the concentration cannot be adequately maintained, additionally a shorter exposure period e.g. 30 minutes can be used.
Hvis 3,5-dichlorphenol bruges som referencekemikalie, skal der fremstilles en opløsning af 1,00 g 3,5-dichlorphenol i 1000 ml vand (15).
The sensitivity of each batch of activated sludge should be checked with a suitable reference chemical on the day of exposure.
Varmt vand og/eller sonikering bør bruges til at fremskynde opløsningen og bringe opløsningen op til volumen, når den er afkølet til stuetemperatur.
The test is typically used to determine the ECx (e.g. EC50) of the test chemical and/or the no-observed effect concentration (NOEC).
Det skal dog sikres, at referencekemikaliet ikke har ændret sig strukturmæssigt.
The inhibition of oxygen uptake by micro-organisms oxidising organic carbon may be separately expressed from that by micro-organisms oxidising ammonium by measurement of the rates of uptake of oxygen in the absence and presence of N-allylthiourea, a specific inhibitor of the oxidation of ammonium to nitrite by the first-stage nitrifying bacteria.
Opløsningens pH skal kontrolleres og om nødvendigt justeres med NaOH eller H2SO4 til pH 7-8.
In this case the percentage inhibition of the rate of oxygen uptake is calculated by comparison of the rate of oxygen uptake in the presence of a test chemical with the mean oxygen uptake rate of the corresponding controls containing no test chemical, both in the presence and absence of the specific inhibitor, N-allylthiourea.