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P de Voogt

Publications and source records attributed to P de Voogt.

15 recordsLinked to original sources
PubMed2001

Aerobic biodegradation studies of nonylphenol ethoxylates in river water using liquid chromatography-electrospray tandem mass spectrometry.

The aerobic biodegradation of nonylphenol ethoxylates (A9PEO) was kinetically investigated in a laboratory-scale bioreactor filled with riverwater, spiked at a concentration of 10 mg L(-1) nonionic surfactants. Analyses of the samples applying liquid chromatography-electrospray mass spectrometry (LC-ES-MS) after solid-phase enrichment revealed a relatively fast primary degradation of A9PEO with >99% degradation observed after 4 days. Contrary to the generally proposed degradation pathway of EO chain shortening, it could be shown that the initiating step of the degradation is omega-carboxylation of the individual ethoxylate chains: metabolites with long carboxylated EO chains are identified (A9PEC). Further degradation proceeds gradually into short-chain carboxylated EO with the most abundant species being AgPE2C. The oxidation of the nonyl chain proceeds concomitantly with this degradation, leading to metabolites having both a carboxylated ethoxylate and an alkyl chain of varying lengths (CAPEC). The identity of the CAPEC metabolites was confirmed by the fragmentation pattern obtained with LC-ES-MS/MS. Both A9PEC and CAPEC metabolites are still present in the bioreactor after 31 days. In the aerobic degradation pathway, A9PEO2 is formed only to a minor extent and is even further degraded in several days. The endocrine disruptor nonylphenol was not found as a metabolite in this study.

Bacteria, Aerobic↗
PubMed2001

Comparative metabolism of phenanthridine by carp (Cyprinus carpio) and midge larvae (Chironomus riparius).

Abiotic transformation of azaarenes in the environment has been analysed extensively, but metabolism is less well described. To further elucidate preliminary observations of interspecific differences in azaarene metabolism by aquatic organisms, phenanthridine biotransformation by midge larvae and carp was studied. In both experiments, 6(5H)-phenanthridinone (phenanthridone) was found as an important metabolite. The fish were clearly capable of metabolising phenanthridine, but in the midge experiment the metabolite was principally formed by bacteria growing on the food and not by the midges. Phenanthridone itself was further degraded to non-observed compounds in both experiments, due to bacteria and midges acting together in the midge experiment, and by carp in the fish experiment. Internal concentrations of phenanthridine and phenanthridone were non-detectable in the midge larvae, but concentrations of both compounds in carp organs suggested a major role of bile and liver. Since phenanthridone did not account for all phenanthridine loss, it was suggested that, apart from phenanthridone degradation, other metabolic pathways may play a role. This study clearly demonstrates the importance of interspecies differences in metabolism, which should not be neglected in risk assessment.

Animals↗
PubMed2001

Phototoxicity of azaarene isomers to the marine flagellate Dunaliella tertiolecta.

Many studies have shown that narcosis or baseline toxicity of polycyclic aromatic hydrocarbons (PAHs) is strongly related to their lipophilicity. For azaarenes, such relationships have also been demonstrated, but for some compounds, deviations from these relationships have been observed, even for closely related compounds such as isomers. In the present study, the toxicity of four azaarene isomer pairs to the marine flagellate Dunaliella tertiolecta was determined. For quinoline, isoquinoline, acridine, phenanthridine, benz[a]acridine, and benz[c]acridine, the 72-h median effective concentrations for growth were 571, 464, 2.10, 14.7, 0.50, and 0.11 microM, respectively. For the five-ringed isomers dibenz[a,i]acridine and dibenz[c,h]acridine, no effects were observed at the highest concentration tested (0.1 and 0.005 microM, respectively). Growth inhibition by the two-, three-, and four-ringed isomer pairs to D. tertiolecta was well described by molecular volume and log Kow, indicating a narcotic mode of action. However, the toxicity of acridine and benz[c]acridine was much higher than that of their respective isomers, phenanthridine and benz[a]acridine, suggesting an additional specific mode of action. Based on the differences in energies between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, acridine and benz[c]acridine are susceptible to ultraviolet (UV) radiation, in contrast to the other tested compounds. Because UV was present, it is therefore argued that the toxicity of both compounds was photoenhanced. Photoenhanced toxicity may increase the environmental hazard of azaarenes, indicating the importance of enlarging the present monitoring of PAHs with phototoxic N-heterocyclic PAHs and incorporating this mode of action in water-quality criteria.

Animals↗
PubMed2000

Inter-laboratory comparison of liquid chromatographic techniques and enzyme-linked immunosorbent assay for the determination of surfactants in wastewaters.

Seven laboratories participated in an inter-laboratory comparison exercise within the framework of the PRISTINE, SANDRINE and INEXsPORT European Union Projects. Solid-phase extraction (SPE) methodologies were used for the extraction of target analytes from wastewaters. The analytical strategies were based on liquid chromatography (LC) coupled to mass spectrometric (MS) or to fluorescent (FL) detection in all cases with the exception of one laboratory using a test-tube enzyme-linked immunosorbent assay kit. Samples were spiked with the surfactants nonylphenolpolyglycol ether, coconut diethanolamide, linear alkylbenzene sulfonate, nonylphenolpolyglycol ether sulfate, alkylpolyglycol ether and secondary alkane sulfonate. After enrichment on previously conditioned SPE cartridges, the SPE cartridges were distributed among the participating laboratories without the information about the amount of spiked surfactants. In addition, SPE cartridges loaded with a real-world environmental sample containing a tannery wastewater were also analyzed. The results of the programme showed that SPE followed by LC-MS techniques are reliable for the surfactants determination at submicrogram to microgram per liter levels in wastewaters. Inter-laboratory precision values were calculated as the reproducibility relative standard deviation (RSD(R)) which was determined from the reproducibility standard deviation (sR) and the average concentration at a particular concentration level. When data from all laboratories were pooled, the RSD(R) values ranged from 5.1 to 28.3% for the determination of target analytes. The most accurate result corresponded to that given for linear alkylbenzene sulfonates. Taking into account that different methodologies were used (including non-chromatographic techniques) and the complexity of the samples analyzed, it can be considered that acceptable reproducibility values were obtained in this inter-laboratory study.

Chromatography, Liquid↗
PubMed1999

Optimization of a matrix solid-phase dispersion method with sequential clean-up for the determination of alkylphenol ethoxylates in biological tissues.

A modified Matrix Solid-Phase Dispersion (MSPD) method with sequential clean-up has been developed to isolate and purify alkylphenol ethoxylates (APEs) and alkylphenols in biological tissues. Elution profile, sequential clean-up adsorbent and experimental set up were optimized. Octadecylsilica was used as the solid-phase for matrix dispersion. Methanol was found to be the optimal eluting solvent for APEs. Aluminium oxide was quite efficient for removing the coeluting interferences. Quantitative analysis was done by reversed-phase HPLC with fluorescence detection. The optimized procedure was applied to analyze both fish and mussel samples. Average recoveries for all spiked tissue samples were greater than 90%. Typical limits of detection amount to tens of ppbs on a wet weight basis.

Aluminum Oxide↗
PubMed1999

Formation and identification of azaarene transformation products from aquatic invertebrate and algal metabolism.

The metabolism of two azaarenes, viz. acridine and phenanthridine, by aquatic organisms was studied in short-term and chronic laboratory tests. The identity of metabolites observed in the test waters was investigated with different analytical methods, including HPLC, GC and hyphenated LC- or GC-MS. The Zebra mussel (Dreissena polymorpha), one green alga species (Selenastrum capricornutum) and periphyton or bacteria transformed acridine into 9[10H]-acridinone. Phenanthridine was transformed into 5[6H]-phenanthridinone by midge (Chironomus riparius) larvae. The findings indicate that closely related isomers may undergo species-specific biotransformation. It was concluded that keto-metabolites are major products in the aquatic fate of benzoquinolines, which may be overlooked in the risk assessment of parent compounds. This study illustrates the typical problems with, as well as the potency of, chromatographic methods in the elucidation of metabolic routes of organic contaminants.

Acridines↗
PubMed1998

Studies of bioaccumulation and biotransformation of PCBs in mustelids based on concentration and congener patterns in predators and preys.

Bioaccumulation of non-, mono-, and di-ortho-substituted chlorobiphenyls (CBs) was investigated in four species of mustelids (weasel, stoat, polecat, and otter) and their preys, from a restricted area in the northern part of The Netherlands. Diets of these mustelids ranged from terrestrial (weasel, stoat, and polecat) to aquatic (otter). Diet-specific biomagnification factors (BMFs), CB in diet relative to CB in mustelids, were calculated for the sum of 28 congeners (SigmaCB), for the sum of the toxic equivalent concentration (SigmaTEQ) and on an individual congener basis. Biotransformation was studied in relation to structural CB properties (vicinal H-atom substitution). In addition, the methylsulphonyl CB-metabolites were determined. The concentration of SigmaCB on lipid weight basis increased in the order weasel < stoat < polecat < otter. On the basis of SigmaTEQ, the order changed to weasel < polecat < stoat < otter. Most of the differences in BMFs between the CBs could be explained by the vicinal H-atom structure-activity rules. For all mustelids, the lowest BMFs were found for congeners with vicinal H-atoms in the meta, para position. Indications were found that all mustelid species can metabolize these congeners. For some of the CBs, their methylsulphonyl-CB metabolites were determined and found to be present in concentrations up to 350-fold higher than those of the parent compounds. In addition, the non-ortho CBs 126 and 169 are selectively retained in the liver of weasel, stoat, and otter. These CBs had the highest BMFs of all congeners. However, rather surprisingly, in polecat the highest BMFs were found for di-ortho-substituted CBs. This animal was able to metabolize all congeners with vicinal H-atoms in the ortho and meta position (non- and mono-ortho CBs). The information concerning the differences in bioaccumulation of CBs for closely related mustelid species increased the understanding of reported differences in PCB toxicity between mink and ferrets, and suggest that weasel, stoat, and otter are at least as sensitive to CBs as are mink, while polecats are less sensitive. As otter is exposed to much higher concentrations of CBs trough their diet than weasel and stoat, the toxic threat of CBs will be the greatest for this animal.

Animals↗
PubMed1996

Ecological hazard assessment of dioxins: hazards to organisms at different levels of aquatic food webs (fish-eating birds and mammals, fish and invertebrates).

An ecological hazard assessment was performed for 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin in the aquatic environment, taking into account four different classes of species which differ with respect to their positions in aquatic food webs: invertebrates, fish, birds preying on aquatic organisms, and mammals preying on aquatic organisms. The most sensitive toxicological endpoints for each class were selected from the literature. These endpoints were extrapolated to no effect concentrations (NECs) in water with a two-level food chain model as indicator for secondary poisoning. From the results it is concluded that fish-eating birds and mammals experience larger hazards from dioxins and related compounds than fish. The limited data available appear to indicate that invertebrates are rather insensitive to dioxins. The study indicates that assessment of secondary poisoning affects environmental quality criteria setting and risk assessment.

Animals↗
PubMed1996

Determination of bioconcentration factors of eight tetrachlorobenzyltoluenes in the zebra mussel Dreissena polymorpha.

Accurate duplicate bioconcentration factors were determined for tetrachlorobenzyltoluenes (TCBTs). This is the first study that quantifies bioconcentration factors for single TCBT isomers. A continuous flow uptake experiment was performed during 21 days with the zebra mussel (Dreissena polymorpha) as a test organism. Bioconcentration factors (BCFs) and rate constants were derived by an iterative integration method. With this method BCFs and rate constants can be derived from experimental data of a bio-concentration test, even if the concentration in the water is not constant and steady state has not been reached. Mean log BCF values of TCBTs ranged from 4.43 +/- 0.05 to 5.19 +/- 0.15 liter.kg-1 on a wet weight basis. The experimental log BCF values were compared with log BCF values of TCBTs, calculated according to linear and polynomial relationships between log BCF and log Kow.

Animals↗
PubMed1991

Retention of neutral and basic heteroaromatic hydrocarbons in RPLC systems and its use in predictive studies. I. Concentration of the organic modifier.

The retention of polynuclear heteroaromatic hydrocarbons in reversed-phase liquid chromatographic systems was studied using methanol-water or acetonitrile-water as the mobile phase. The relation between the concentration of the modifier and the capacity factor was investigated, and capacity factors in pure water were obtained by means of extrapolation of this relation and were used in quantitative chromatographic retention-activity relationships. It was shown that the general equation for the relationship between the n-octanol/water partition coefficient (log Kow) and retention of apolar compounds in octadecyl-silica/methanol-water systems, first presented by Tomlinson and Hafkenscheid, is valid for neutral heteroaromatic hydrocarbons. For basic heteroaromatic compounds, this relationship is not valid. Both log Kow and the logarithm of the bioconcentration factor in the guppy (Poecilia reticulata) of neutral heteroaromatic hydrocarbons can be predicted satisfactorily from capacity factors extrapolated to pure water.

Chromatography, High Pressure Liquid↗
PubMed1988

Prediction of environmental fate and effects of heteroatomic polycyclic aromatics by QSARs: the position of n-octanol/water partition coefficients.

The HPLC and TLC retention, n-octanol/water partition coefficients (log Kow), bioconcentration factors, and acute toxicity data of 29 heteroatomic polycyclic aromatic hydrocarbons and 7 parent polycyclic aromatics were determined experimentally. For the same set of compounds, molecular weights, fragmental log Kow values, and molecular connectivities were calculated. Quantitation of the mathematical relationships between the variables was used to validate the predictive potential of various parameters. The importance of log Kow in predictive studies is highlighted. It is concluded that the internal concentration of a pollutant in the organism should be used as a parameter in future QSAR work.

1-Octanol↗
PubMed1984

Cadmium/zinc relationships in kidney cortex and metallothionein of horse and red deer: histopathological observations on horse kidneys.

Cadmium and zinc were determined in kidney cortex of 63 horses and 51 red deer (Cervus elaphus). Cadmium and zinc were also determined in protein fractions obtained by Sephadex chromatography of kidney cortex from 10 horses and 4 red deer. Histopathological parameters in kidney cortex of horses were compared to cadmium content. The metal contents (on wet weight basis) in kidney cortex of the horses were 0.31 +/- 0.22 mmole Cd/kg (range 0.03-1.21) and 0.63 +/- 0.17 mmole Zn/kg (range 0.36-1.23). The Zn content increased with the Cd content, the Zn increase being less at higher concentrations. No significant increase of the Cd content with age of the horses (range 2-19 years) was found. The metal contents in kidney cortex of the red deer were 0.030 +/- 0.031 mmole Cd/kg (range 0.002-0.13) and 0.51 +/- 0.37 mmole Zn/kg (range 0.30-2.82). Here the Zn content did not increase significantly with Cd content, and in this case a positive linear relation of Cd content with age of the deer (range 0-11 years) was observed. The molar Zn/Cd ratio in the metallothionein fractions of horse kidney cortex was less variable at higher Cd contents. All Cd and the increase of Zn above an average basal level of 0.36 mmole Zn/kg was recovered in the metallothionein fractions. No gross histopathological changes could be observed in kidney cortex of the horses. Nevertheless a slight increase of the thickness of the basement membrane of Bowman's Capsule and also of the diameter of Bowman's Capsule in relation to Cd content up to 0.3 mmole/kg could be observed.

Animals↗
PubMed1981

An analytical procedure for the determination of cadmium in human placentae.

Cadmium was determined in human placental tissue by flameless atomic absorption spectrometry (AAS). Several sampling, homogenizing and decomposition procedures were tested with regard to their suitability for flameless AAS. Main criteria involved recovery, representativity contamination, accuracy and precision. Analysis of biological reference materials yielded results in agreement with reported certified values or grand means. A sampling strategy was developed based on expected placental distribution patterns of the metal. The sampling method used appeared to be satisfactorily representative of the organ as a whole. During 1978 and 1979 placentae were collected from mothers living in the Amsterdam area in the Netherlands. Mean placental cadmium levels of smokers (66 +/- 33 ng/g dry weight) appeared to be slightly elevated compared to those of non-smokers (51 +/- 20 ng/g).

Cadmium↗