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P de Voogt,
B Halling-Sørensen, B van Hattum,
P.T. Holland,
F Ingerslev,
A. Johnson,
M. Jurgens,
A Katayama,
W. Klein,
N. Kurihara,
J C Leblanc,
K.D. Racke,
J.T. Sanderson,
M Shemesh,
L S Shore,
E. Vaclavik,
M van den Berg,
P Verger
Pure and Applied Chemistry 12/2012; · 2.79 Impact Factor
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ABSTRACT: The dynamical behaviour of an aquatic ecosystem stressed by limiting nutrients and exposure to a conservative toxicant is investigated. The ecosystem downstream of a pollution source consists of: nutrients, biotic pelagic and benthic communities, and detritus pools in the water body and on the sediment. The long-term dynamic behaviour of this system is analysed using bifurcation theory. A reference state is defined and our aim is to quantify the effects of toxicological (toxic exposure), ecological (feeding, predation, competition) and environmental stressors (nutrient supply, dilution rate). To that end we calculate the ranges of stress levels where the long-term dynamics (equilibrium, oscillatory or chaotic behaviour) is qualitatively the same. In this way we obtain levels of toxicological loading where the abundances of all populations are the same as in the reference case, the no-effect region. We will also calculate toxic exposure levels that do not lead to a change in the composition of the ecosystem, and therefore its structure, with respect to the reference unexposed situation, but where population abundances and internal toxicant concentrations may have been changed quantitatively. The model predicts that due to indirect effects even low sublethal toxic exposure can lead to catastrophic changes in the ecosystem functioning and structure, and that the long-term sensitivities of oligotrophic and eutrophic systems to toxic stress are different.
Ecotoxicology and Environmental Safety 01/2011; 74(4):929-39. · 2.29 Impact Factor
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ABSTRACT: Trace elements (Fe, Mn, Al, Zn, Cr, Cu, Ni, Pb, Cd, Hg, and As) and stable isotope ratios (delta(13)C and delta(15)N) were analyzed in sediments, invertebrates, and fishes from a tropical coastal lagoon influenced by iron ore mining and processing activities to assess the differences in trace element accumulation patterns among species and to investigate relations with trophic levels of the organisms involved. Overall significant negative relations between trophic level (given by (15)N) and trace element concentrations in gastropods and crustaceans showed differences in internal controls of trace element accumulation among the species of different trophic positions, leading to trace element dilution. Generally, no significant relation between delta(15)N and trace element concentrations was observed among fish species, probably due to omnivory in a number of species as well as fast growth. Trace element accumulation was observed in the fish tissues, with higher levels of most trace elements found in liver compared with muscle and gill. Levels of Fe, Mn, Al, and Hg in invertebrates, and Fe and Cu in fish livers, were comparable with levels in organisms and tissues from other contaminated areas. Trace element levels in fish muscle were below the international safety baseline standards for human consumption.
Archives of Environmental Contamination and Toxicology 03/2010; 59(3):464-77. · 1.93 Impact Factor
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ABSTRACT: The status of the contamination of Dutch marine harbor sediments was reevaluated after a period in which emissions from point sources had been greatly reduced. Data on sediment chemistry from 1999 and 2000 were assessed against screening levels (SLs) selected from available sediment quality guidelines and representing a low probability of adverse biological effects. This yielded a ranking of the environmental hazard of 22 contaminants. Most of the sediments were silty material; every year 15 to 25 million m3 of such material is dredged from Dutch harbors. Some 34% of the volume exceeded one or more SLs. The contaminants of concern were tributyltin (TBT), mineral oil (petroleum hydrocarbons), polychlorinated biphenyls (PCBs), and mercury. The PCB and mercury contamination is the legacy of historic inputs; the TBT and mineral oil contamination is related to present-day shipping activity. Concentrations of trace metals, rare earth elements, organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were low and apparently of minor environmental concern. It is concluded that the risk assessment would be improved by laboratory testing of adverse biological effects.
Archives of Environmental Contamination and Toxicology 11/2003; 45(3):306-16. · 1.93 Impact Factor
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ABSTRACT: The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity, biomarker responses and benthic community changes shortly after dumping at the 'North' site had ceased and at the start of disposal at the new dumping site 'Northwest'. During the period of dumping, very few benthic invertebrates were found at the North site. Concentrations of cadmium, mercury, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and tributyltin (TBT) in the fine sediment fraction (<63 microm) from this site were 2-3 times higher than at the reference site. In four different bioassays with marine invertebrates the sediments showed no acute toxic effects. In tissue (pyloric caeca) of resident starfish Asterias rubens, residual levels of mercury, zinc, PCBs and dioxin-like activity were never more than twice those at the reference site. Four different biomarkers (DNA integrity, cytochrome P450 content, benzo[a]pyrene hydroxylase activity and acetylcholinesterase inhibition) were used on the starfish tissues, but no significant differences were found between North and the reference site. Minor pathological effects were observed in resident dab Limanda limanda. One year after dumping had ceased at the North site, a significant increase in the species richness and abundance of benthic invertebrates and a concomitant decrease in the fine sediment fraction of the seabed were observed. After 8.2 million m3 of moderately contaminated dredged material had been dumped at the new dumping site Northwest, the species richness and abundance of benthic invertebrates declined over an area extending about 1-2 km eastwards. This correlated with a shift in sediment texture from sand to silt. The contamination of the fine sediment fraction at the Northwest location doubled. It is concluded that marine benthic resources at and around the dumping sites have been adversely affected by physical disturbance (burial, smothering). However, no causal link could be established with sediment-associated contaminants from the dredged spoils.
Environmental Pollution 01/2003; 124(1):17-31. · 3.75 Impact Factor
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P de Voogt,
B. Halling-Sorensen, B van Hattum,
P.T. Holland,
F Ingerslev,
S. Johnson,
M. Jurgens,
A Katayama,
W. Klein,
N. Kurihara,
J C Leblanc,
K.D. Racke,
J.T. Sanderson,
M Shemesh,
L S Shore,
E. Vaclavik,
M van den Berg,
P Verger
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ABSTRACT: This main topic of the project and symposium includes the issue of releases of endocrine
active substances (EASs) and their monitoring in the environment, food, and feed in
order to provide the full set of criteria relevant for exposure assessment. Much less research
has been devoted to these areas as compared to investigations on the effects. Issues of special
importance regarding exposure to EASs, both from a research and risk management
point of view, predominantly result from the fact that high-potency natural products are released
as well as anthropogenic substances.
In order to provide reliable information for risk assessment and management, substantial
research, methodological improvements, and improvements in data interpretation are
needed regarding the following: releases and technologies for their mitigation; monitoring;
establishment of background levels; transport, partitioning, persistence, degradation, and metabolism
of EASs; dealing with “joint toxicity”; and providing reliable analytical methodology
conforming to the principles of quality assurance.
Phytohormones play a special role in this whole area since they may be used as food
amendments.
Pure and Applied Chemistry 01/2003; 75(11-12):1949-1953. · 2.79 Impact Factor
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ABSTRACT: A sensitive LC-electrospray MS-MS method using off-line solid-phase extraction for the determination of diuron and Irgarol 1051 has been developed, enabling determination of both compounds at sub-ppt levels. Diuron and Irgarol 1051 are used as alternatives for tributyltin in antifouling paints that prevent growth on boats, and an increase in their application is anticipated because of the upcoming ban on tributyltin in 2003. In 2000, a survey was carried out to assess contamination with diuron and Irgarol 1051 of a number of Dutch marinas and coastal waters. Depending on the time of year, both compounds were encountered at levels higher than the maximum permissible concentrations of 430 and 24 ng/l for diuron and Irgarol 1051, respectively. Outside marinas at reference locations, concentrations were much lower, depending on the geographical situation and the nature of the water exchange with the environment related to tidal cycles. A seasonal influence was observed with highest levels in summer, corresponding to the yachting season for both compounds. For diuron, use in agriculture could have contributed to the high concentration encountered in surface waters.
Journal of Chromatography 10/2002; 970(1-2):183-90. · 4.53 Impact Factor
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ABSTRACT: A hydrological model was constructed with the commercially available modelling environment ECoS for the calculation of mixing plots of dissolved pesticide concentrations in the Scheldt Estuary. The model was based on a one-dimensional advection-dispersion equation and dispersion coefficients were calculated from measured salinity profiles. The model could correctly predict the movement of water masses within the estuary. Nominal flushing times of the estuary were calculated with the fraction-of-freshwater method and ranged between 25 and 95 days, depending on the freshwater discharge. Model calculations demonstrated that the application-related time profiles of pesticide input may well induce curvature in the calculated estuarine mixing plot even if the pesticide behaves conservatively. Calculated mixing plots were compared with experimental data and good agreement was obtained between the measurements and the conservative mixing plot of atrazine. For metolachlor an additional direct emission had to be modelled to explain the differences between the experimental data and the conservative mixing plot. For dichlorvos and simazine. on the other hand, an estuarine loss constant had to be included in the model. Using a least-squares procedure the estuarine loss constants for dichlorvos and simazine were estimated at half-lives of five and 26 days, respectively. Because mixing plots were strongly influenced by the time profiles of pesticide input, standard procedures in which net fluxes are calculated from mixing plots, were not applicable. Therefore, net fluxes were calculated with a newly developed procedure in which the estuarine loss constants and the estuarine flushing time were combined. For the non-conservative compounds dichlorvos and simazine, the net fluxes to the North Sea were found to be 96 and 64%, respectively, lower than the gross fluxes transported by the River Scheldt.
Environmental Pollution 02/2002; 116(1):75-84. · 3.75 Impact Factor
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ABSTRACT: As part of the Fluxes of Agrochemicals into the Marine Environment (FAME) project, the gross fluxes of selected pesticides (i.e. the herbicides atrazine, simazine, alachlor and metolachlor, the atrazine degradation product desethylatrazine, the insecticide dichlorvos and the antifouling agent Irgarol 1051) transported by the river Scheldt and the Canal Ghent-Terneuzen were determined from March 1995 through February 1997. In general, the observed temporal trends were related to the application period of the pesticides, except for metolachlor for which elevated concentrations were observed in the winter of 1995-1996. Relatively large gross fluxes were found for desethylatrazine compared with its parent compound. A study on the estuarine behaviour of pesticides showed distinct differences between the compound classes. The mixing plots of the organophosphorus insecticides dichlorvos and diazinon revealed clear evidence of estuarine loss processes which agrees with their low DT50 values reported for water/sediment systems, their relatively high Henry's law constants and, for diazinon, its relatively high Koc value. The mixing plots of the acetanilides alachlor and metolachlor were strongly influenced by an additional direct emission into the estuary, which was evident from a maximum in dissolved concentration near a salinity of 10@1000. An apparent conservative behaviour was observed for the triazine compounds atrazine and Irgarol 1051. This was in contrast to simazine, which showed an apparent non-conservative behaviour. However, the time profiles of the riverine concentrations of simazine did not exclude that the observed curvature was solely caused by estuarine losses; therefore, additional modelling is required. In a follow-up study a suitable hydrological model of the Scheldt estuary was constructed; the results will be presented in a forthcoming paper (Steen, R.J.C.A., Evers, E.H.G., Van Hattum, B., Cofino, W.P. and Brinkman, U.A.Th. Net fluxes of pesticides from the Scheldt estuary into the North Sea: a model approach. Environmental Pollution, submitted.
Environmental Pollution 02/2001; 115(1):65-79. · 3.75 Impact Factor
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ABSTRACT: Off-line solid-phase extraction (SPE) combined with liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS-MS) was used to study the estuarine behaviour of the polar pesticides, atrazine, chloridazon, diuron and metolachlor, and their transformation products (TPs), hydroxyatrazine (HA), desisopropylatrazine (DIA), desethylatrazine (DEA), 3,4-dichlorophenylmethylurea (DPMU) and monuron. The compounds were identified by comparing their LC retention times and product-ion spectra with those of standard solutions. In all but one case the detection limits of the method were sufficient to determine the compounds of interest over the entire salinity range in the estuary. The concentrations of the dissolved pesticides ranged from 70 ng l-1 for chloridazon to 1350 ng l-1 for diuron. The levels of TPs were 3-8% of the levels of their parent pesticide. The mixing plots of polar pesticides and their TPs indicated that TPs, which are present in fresh river water, are conservatively transported to the sea and that no additional amounts of TPs are formed during their transport through the estuary. The one exception was HA, of which approximately 10% of the amount transported to the North Sea is formed in the lower part of the estuary by photochemical oxidation of atrazine. The latter was concluded from the ratios of each analyte over the sum total of the parent pesticide and all TPs along the salinity gradient, which proved to be a useful tool for identifying such estuarine transformations.
Journal of Environmental Monitoring 01/2001; 2(6):597-602. · 1.99 Impact Factor
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ABSTRACT: 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.
Archives of Environmental Contamination and Toxicology 12/1998; 35(4):654-65. · 1.93 Impact Factor
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ABSTRACT: In this study, the availability of physico-chemical and ecotoxicological information on 78 transformation products for 20 regularly used pesticides in the open literature is evaluated. Based on this information, it is attempted to predict the relative risk for the aquatic environment of each transformation product in comparison to its parent pesticide. It is concluded that for the 78 transformation products selected, the data set on physico-chemical and ecotoxicological behaviour is not very large. Measured log Kow values and other physico-chemical properties are known for only 30-40% of the selected transformation products. The overall reliability of the collected physico-chemical values is considered to be moderate to slight, while for the ecotoxicological data set, reliability is considered to be sufficient. In many cases, there is a need for more information especially on the persistency and no-observed-effect concentrations of the pesticide's transformation products. In general, over 50% of the transformation products of triazines, carbamates and phenoxypropionic acids pose, in theory, a similar to higher risk than their parent pesticide, while over 50% of the transformation products of synthetic pyrethroids, organophosporous pesticides and dithiocarbamates probably pose less risk. High risk was expected for products with high accumulation or persistency in sediment and/or high toxicity together with considerable bioaccumulation (potential) or relatively high concentrations or persistency in water. A generalization of the joint features that caused an increased risk for ecosystems could not be made for most pesticide classes. Exceptions are the synthetic pyrethroids, for which transformation products with a similar or even higher log Kow than the parent pesticide caused an increased potential risk, while for the carbamates the presence of the carbamate group in the transformation product was the joint characteristic of chemicals with predicted increased risk. For three transformation products, monitoring data based on concentrations measured in surface water in The Netherlands were compared with maximum permissible concentrations. This comparison indicated that two of these compounds pose a potential risk of adverse effects in the field situation in Dutch aquatic ecosystems. For all other transformation products, the potential risk in the field situation could not be established because of the absence of monitoring data.
Science of The Total Environment 11/1998; 222(3):167-83. · 3.29 Impact Factor
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ABSTRACT: 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 (ΣCB), for the sum of the toxic equivalent concentration (ΣTEQ) 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 ΣCB on lipid weight basis increased in the order
weasel < stoat < polecat < otter. On the basis of ΣTEQ, 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.
Archives of Environmental Contamination and Toxicology 10/1998; 35(4):654-665. · 1.93 Impact Factor
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ABSTRACT: In the serious decline of European otters (Lutra lutra) over the last decades, polychlorinated biphenyls (PCBs) are considered to be one of the major factors. As no experiments can be conducted with otters, an eco-epidemiological study was performed to derive no observed effect concentrations (NOECs) for PCBs in the otter. A strong negative correlation was found between hepatic vitamin A and polychlorinated biphenyl (PCB) concentrations expressed as TCDD-equivalents (TEQs), coinciding with a higher incidence of infectious diseases. The no-effect concentration for vitamin A reduction was 2 ng TEQ/g lipid, 10-fold reduction was already found in animals with 5 ng TEQ/g lipid. The TEQ-levels measured with a reporter gene assay based on chemical-activated luciferase expression (the CALUX assay) correlated well with the TEQ levels calculated based on non- and mono-ortho PCB concentrations. The TEQ levels in blood and liver correlated well when expressed on a lipid basis. In living captive otters blood plasma TEQ levels (either measured based on gas chromatography (GC) or CALUX measurement) were lower than in the feral otters, and positively correlated with plasma total and free thyroid hormone but not with plasma retinol levels. Hepatic vitamin A concentration was found to be a physiologically relevant effect parameter. The NOEC for hepatic vitamin A reduction was translated into TEQ levels in fish and sediment. The CALUX response in 50-500 μl blood plasma proved to be a sensitive non-destructive biomarker for quantification of internal TEQ levels.
Environmental Toxicology and Pharmacology 10/1998; 6(2):91-102. · 1.47 Impact Factor
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ABSTRACT: Trace metal levels in water, sediments and freshwater isopods from 28 different water systems in the Netherlands were measured during the period of 1986 to 1989. Distinct element-specific internal distribution patterns were present, with Cd and Cu stored mainly in the hepatopancreas (30-60% of total body burden) and Pb and Zn in the hindgut and exoskeleton with hemolymph. Mean whole-body concentrations of the non-essential elements Cd and Pb in individually analyzed isopods varied over three orders of magnitude between populations. The variability of Zn and Cn were within one order of magnitude difference. The variability of trace metal levels between populations exceeded within-population variability. Within-population variability was related to seasonal and biological factors such as body weight, sex, reproductive state, and species abundance. The highest concentrations were found in small juvenile animals compared to adults, females compared to males, and Proasellus meridianus compared to Asellus aquaticus. However, after correction for size effects using a power-curve regression model no significant differences remained between sex and species. Seasonal fluctuations accounted for 33-79% of the within population variability. Trace metal levels in isopods were predicted from concentrations in water and sediments in combination with aqueous Ca, Cl-, DOC, and sediment characteristics (Org-C, clay, CaCO3) using a multiple regression model. With this predictive model 42-63% of the variance could be explained. In situ determined partitioning coefficients (apparent BCF, biota-sediment BSAF, and sediment-water distribution coefficient Kd) varied between locations and covaried with factors related to trace metal bioavailability (aqueous Ca, Cl- and DOC, sediment Org-C, clay, and CaCO3). Especially for Cd and Cu field-derived BCF values were in agreement with previously reported experimental studies. It is concluded, that A. aquaticus may be a suitable candidate-organism for biomonitoring available trace metal levels in littoral freshwater systems. Finally, some practical recommendations are given for future field surveys with freshwater isopods with respect to sample size, allometric standardization, period of sampling and statistical design.
Archives of Environmental Contamination and Toxicology 11/1996; 31(3):303-18. · 1.93 Impact Factor
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ABSTRACT: An extensive study on the presence of nine organotin compounds (OTs) in a freshwater foodweb was made, using newly developed analytical procedures in order to obtain insight in accumulation and degradation processes. Tributyltin (TBT), Triphenyltin (TPT) and their degradation products were detected. Zebra mussels, eel, roach, bream, pike, perch, and pike perch and cormorant showed high OT body concentrations. At the lower trophic levels, phenyltin concentrations were higher in benthic species while butyltin concentrations were higher in pelagic species. This indicates that TBT is passed on primarily via the water, while TPT is passed on to a larger extent via the sediment. At the higher trophic levels, net bioaccumulation of TPT was greater than that of TBT, resulting in relatively higher TPT concentrations. High concentrations of biodegradation products of TBT, but not of TPT, were found in the livers of fish and birds, which indicates that TBT is more easily metabolized than TPT. A comparison with literature data of fish lethal body concentrations revealed that fish in the field may be endangered. With birds, the highest concentrations of OTs were present in liver and kidney and not in subcutaneous fat, which confirms that OTs accumulate via different mechanisms than traditional lipophilic compounds. As a whole the OT concentrations found in the foodweb may be considered to be quite alarming.
Archives of Environmental Contamination and Toxicology 11/1996; 31(3):319-28. · 1.93 Impact Factor
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ABSTRACT: Cadmium, lead, zinc and copper concentrations were determined in 15 species of freshwater macro-invertebrates collected from a littoral foodweb. Indications of a biomagnification process, in which predators had a higher concentration than their prey, were only found in the case of zinc. Organisms with copper as an essential component of their haemolymph, such as Crustacaea, Gastropoda and Bivalvia, contained higher concentrations of that metal than other species. Another important factor in the determination of trace metal concentrations, apart from physiological equipment, was body weight, resulting in higher concentrations in smaller, and lower concentrations in larger, organisms. This seemed to be the case within populations of single species, as well as in different species of deposit feeders. Furthermore, feeding habit, proximity to the sediment and physico-chemical factors appeared to be determining factors for trace metal concentrations in macro-invertebrates. The results of this study are related to ecotoxicological theories which explain the causes of pollutant residues in organisms. It is concluded that various explanations for the differences in pollutant residues, e.g. trophic level, feeding habit, body weight, association with the substrate, physiological equipment and abiotic factors, are valid.
Science of The Total Environment 12/1989; 87-88:477-94. · 3.29 Impact Factor
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ABSTRACT: Experiments were conducted to determine the kinetics and relative importance of aqueous and dietary uptake of cadmium by the freshwater isopod Asellus aquaticus (L.). Test animals were exposed during 30 days to aqueous Cd in a continuous flow system (exposure levels: 0.2 - 10 microg litre(-1)) and kept on a diet of previously contaminated Elodea sp. (range of Cd concentrations: 2-350 microg g(-1), dry weight). Preceding semi-static experiments on dosage-control of the dietary factor revealed a rapid uptake of Cd by Elodea, with relatively high concentration factors (CF), which ranged from 4.8 to 5.5 (dry weight log (CF) after 16 days). For Asellus uptake from water appeared to be the predominant route. Highly significant bioconcentration of cadmium from water was observed in the animals, even at exposure levels below 1.0 microg litre(-1). In the various treatments, direct uptake from water accounted for 50-98% of the body burdens after 30 days exposure. The experimental results were described with a first order one-compartment bioaccumulation model. Model parameter estimates (mean +/- standard error) were obtained for rate constant of uptake (560 +/- 110 day(-1)), rate constant of elimination (0.032 +/- 0.017 day(-1)) and assimilation efficiency of Cd uptake from food (1.1 +/- 0.7%). The (dry weight) bioconcentration factor (BCF) and bioaccumulation factor (BAF) for extrapolated steady state conditions were estimated at 18 000 (BCF) and 0.08 (BAF). Experiments conducted at two different pH levels (5.9 versus 7.6) revealed no significant effects of pH on the uptake of aqueous Cd by the isopods. The results are discussed in relation to their potential significance to the field situation.
Environmental Pollution 02/1989; 62(2-3):129-51. · 3.75 Impact Factor
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ABSTRACT: Experiments were conducted to determine the kinetics and relative importance of aqueous and dietary uptake of cadmium by the freshwater isopod Asellus aquaticus (L.). Test animals were exposed during 30 days to a queous Cd in a continuous flow system (exposure levels: 0·2 − 10 μg litre−1) and kept on a diet of previously contaminated Elodea sp. (range of Cd concentrations: 2–350 μg g−1, dry weight). Preceding semi-static experiments on dosage-control of the dietary factor revealed a rapid uptake of Cd by Elodea, with relatively high concentration factors (CF), which ranged from 4·8 to 5·5 (dry weight log (CF) after 16 days).For Asellus uptake from water appeared to be the predominant route. Highly significant bioconcentration of cadmium from water was observed in the animals, even at exposure levels below 1·0 μg litre−1. In the various treatments, direct uptake from water accounted for 50–98% of the body burdens after 30 days exposure.The experimental results were described with a first order one-compartment bioaccumulation model. Model parameter estimates (mean ± standarderror) were obtained for rate constant of uptake (560 ± 110 day−1), rate constant of elimination (0·032 ±0·017 day−) and assimilation efficiency of Cd uptake from food (1·1 ± 0·7%). The (dry weight) bioconcentration factor (BCF) and bioaccumulation factor (BAF) for extrapolated steady state conditions were estimated at 18 000 (BCF) and 0·08 (BAF). Experiments conducted at two different pH levels (5·9 versus 7·6) revealed no significant effects of pH on the uptake of aqueous Cd by the isopods. The results are discussed in relation to their potential significance to the field situation.
Environmental Pollution. 01/1989; 62:129-151.
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ABSTRACT: 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).
International Journal of Environmental Analytical Chemistry 02/1981; 10(2):121-33. · 1.16 Impact Factor
