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Organisationseinheit der BAM
This study comprises the development of enzyme-linked immunosorbent assays (ELISAs) for the quantification of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in complex aqueous matrices without any sample clean-up procedures. Salinity and dissolved organic matter were selected as potential interfering agents in the analysis of E2 and EE2. The optimization was performed in order to (i) overcome matrix effects, and to (ii) increase sensitivity. The addition of a sample buffer containing bovine serum albumin (BSA) prior to the sample was found to decrease the influence of matrix effects. Moreover, adjustments of this buffer's pH together with the optimization of tracer (T) dilution and incubation time were undertaken in order to lower the quantification range. The optimized methods allowed the quantification of E2 and EE2 in the ranges 0.03200 µg L-1 and 0.0210 µg L-1, respectively. The assays were applied to real aqueous samples. It was possible to do a first approach to the levels of E2 in Portuguese surface and waste waters; however, it was not feasible to detect EE2 in the samples tested.
The transport and fate of hydrophobic organic contaminants in the environment involve complex phenomena that are influenced by many processes that include sorption by soil components. Sorption behavior of EE2 molecules onto different soil samples was studied and results correlated with the content and type of organic matter present. The highest Κ value, among all soils presented in this study, was obtained for soil fertilized with compost (1.22) which presented the highest organic carbon content. Also the sorption behavior depends greatly on the soil specific organic matter characteristics. A strong positive correlation was observed between aromatic and carboxylic units and ΚOC values. The results also suggested an association of the EE2 aromatic nuclei face to face with the surface and/or another EE2 molecule and also sorbentsorbate interactions due to hydrogen or covalent bonding, likely to occur due to the presence of phenolic function at C-3 and hydroxyl function at C-17 of the EE2 molecules that can react with carboxylic functional groups of soil organic matter. The stronger EE2 sorbs to soil organic matter lower is the leaching into drinking water resources and runoff to rivers and surface water, minimizing its residual toxicity.
The implementation of the Water Framework Directive (2000/60/EC) requires the establishment of monitoring programs. However, conventional procedures for sample preparation prior to chromatographic analysis are rather expensive and time consuming, being the development of cost-effective and easy tool a necessity. The aim of this work was to develop an enzyme-linked immunosorbent assay (ELISA) able to determine atrazine in water samples. Matrix effects evaluation showed that the increase of humic acid (HA) concentration leads to flattened calibration curves and to the loss of the sigmoidal shape. However, such interference was overcome, by the presence of an environmental sample buffer, incubated together with the samples. Recoveries from 88.5 to 119.2 % were obtained in the presence of HA concentrations up to 20 mg-1. An analytical range from 0.003 to 1 µgL-1 was obtained, and atrazine was detected in a sewage treatment plant with concentrations ranging from 14 to 52 ngL-1.
In Coastal Systems, pollutants as pharmaceutical drugs exert changes from the molecular to the organism level in marine bivalves. Besides pollutants, Coastal Systems are prone to changes in environmental Parameters, as the alteration of salinity values because of Climate Change. Together, these Stressors (pharmaceutical drugs and salinity changes) can exert different threats than each Stressor acting individually; for example, salinity can change the physical-chemical properties of the drugs and/or the sensitivity of the organisms to them. However, limited Information is available on this subject, with variable results, and for this reason, this study aimed to evaluate the impacts of salinity changes (15,25 and 35) on the effects of the antiepileptic carbamazepine (CBZ, 1 (ig/L) and the antihistamine cetirizine (CTZ, 0.6 pg/L), when acting individually and combined (CBZ + CTZ), in the edible clam Ruditapes philippinarum. After 28 days ofexposure, drugs concentrations, bioconcentration factors and biochemical parameters, related to clam's metabolic caparity and oxidative stress were evaluated. The results showed that dams under low salinity suffered more changes in metabolic, antioxidant and biotransformation activities, in comparison with the remaining salinities under study. However, limited impacts were observed when comparing drug effects at low salinity. Indeed, it seemed that CTZ and CBZ + CTZ, under high salinity (salinity 35) were the worst exposure conditions for the dams, since they caused higher leveis of cellular damage. It Stands out that salinity changes altered the impact of pharmaceutical drugs on marine bivalves.
In coastal systems, organisms are exposed to amultitude of stressors whose interactions and effects are poorly studied. Pharmaceutical drugs and Climate Change consequences, such as lowered pH, are examples of stressors affecting marine organisms, as bivalves. Although a vast literature is available for the effects of these stressors when acting individually, very limited information exists on the impacts that the combination of both can have on marine bivalves. For this reason, this study aimed to evaluate the impacts of a simulated ocean acidification scenario (control pH, 8.0; lowered pH, pH 7.6) on the effects of the antiepileptic carbamazepine (CBZ, 1 μg/L) and the antihistamine cetirizine (CTZ, 0.6 μg/L), when acting individually and combined (CBZ + CTZ), on the edible clam Ruditapes philippinarum. After 28 days of exposure, drug concentrations, bioconcentration factors and biochemical parameters related to the clams' metabolic capacity and oxidative stress were evaluated. The results showed that R. philippinarum clams responded differently to pharmaceutical drugs depending on the pH tested, influencing both bioconcentration and biological responses. In general, drug combined treatments showed fewer impacts than drugs acting alone, and acidification seemed to activate at a higher extension the elimination processes that were not activated under control pH. Also, lowered pH per se exerted negative impacts (e.g., cellular damage) on R. philippinarum and the combination with pharmaceutical drugs did not enhance the toxicity.
Sulfamethoxazol (SMX),a sulfonamide, is a widely used bacteriostatic antibiotic and therefore a promising marker for the entry of anthropogenic Pollution in the environment. SMX is frequently found in wastewater and surface water. This study presents the production of high affinity and selective polyclonal antibodies for SMX and the development and Evaluation of a direct competitive enzyme-linked immunosorbent assay(ELISA)for the quantification of SMX in environmental watersamples. The crystal structures of the cross-reacting compounds sulfamethizole, N4-acetyl-SMX andsuccinimidyl-SMX were determined by x-ray diffraction aiming to explain their high cross-reactivity. These crystal structures are described for the first time. The quantification range of the ELISA is 0.82–63 µg/L. To verify our results, the SMX concentration in 20 environmental samples,including wastewater and surfacewater,was determined by ELISA and tandem mass spectrometry(MS/MS).A good Agreement of the measured SMX concentrations was found with average recoveries of 97–113%for the results of ELISA compared to LC-MS/MS.
Carbamazepine (CBZ), an antiepileptic drug, is one of the most commonly detected pharmaceutical drugs in aquatic ecosystems, and is used as a marker of urban pollution. Since CBZ is designed to exert a biological effect, when it reaches aquatic environment high probability exist for toxic effects on non-target organisms. The present study evaluated the acute toxicity of environmentally relevant concentrations of CBZ (0.00, 0.03, 0.30, 3.00, 9.00 µg/L) in the edible clams Venerupis decussata (a native species) and Venerupis philippinarum (an invasive species) collected from the Ria de Aveiro. The effects on both species were assessed through the use of a battery of biomarkers mainly related with health status and oxidative stress. Furthermore, in this work an alternative and promising tool, the direct competitive immunoassay ELISA, for the direct CBZ quantification in clam's tissues, was applied.
The results of the present work showed that CBZ in clam's tissues increased with the exposure concentration and V. decussata gave slightly higher values than V. philippinarum. Although the clams accumulated lower levels of CBZ than the concentration of exposure, these concentrations were enough to impair the health status and induce oxidative stress. However, a different response to CBZ was observed in the two species. While in V. philippinarum the lipid peroxidation levels increased at the highest CBZ concentration (9.00 µg/L), in V. decussata a significant decrease was seen. Moreover, glutathionse S-transferase activity was stimulated in V. decussata and decreased in V. philippinarum. Nevertheless, an induction of glutathione reductase, superoxide dismutase and cytochrome P450 3A4 activities was found in both species as a result of the exposure. The results indicate that, probably, V. philippinarum have a less efficient antioxidant system than V. decussata, and are therefore less capable to neutralize oxidative stress and consequently more sensitive to CBZ. The risk quotient determined for the Ria de Aveiro was higher than 1 indicating that a ecotoxicological risk is suspected. Furthermore, bioaccumulation of CBZ in clams should be taken into consideration since this chemical might be transferred along the food chain and affect non-target organisms.
This study comprises the development of an enzyme-linked immunosorbent assay (ELISA) for the quantification of caffeine in complex aqueous matrices without any sample clean-up procedure. Salinity and dissolved organic matter were selected as potential interfering agents. The addition of a sample buffer containing bovine serum albumin (BSA) prior to the sample was found to decrease the influence of those interfering agents. The working range of the developed method was 0.1–100 µg L- 1. Quantification of caffeine was possible in 43 out of 51 real aqueous samples, at values between < LOD and 15 µg L- 1. Results correlate well with those obtained by LCMS/MS. To the best of our knowledge this is the first study dealing with the quantification of caffeine in Portugal's surface waters.
Estrogens, such as 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), are the major responsible for endocrine-disrupting effects observed in aquatic environments due to their high estrogenic potency, even at concentrations ranging from pg L-1 to ng L-1. Thus, it is essential to develop analytical methodologies suitable for monitoring their presence in water samples. Dispersive liquidliquid microextraction (DLLME) was used as a pre-concentration step prior to the quantification of E2 and EE2 by enzyme-linked immunosorbent assay (ELISA). First, an evaluation of the effect of DDLME on the E2 and EE2 ELISA calibration curves was performed. Since the extraction procedure itself had an influence on the ELISA optical density (OD), it became necessary to subject, not only the samples, but also all the standards to the DLLME process. Working ranges were determined, being between 1.2 and 8000 ng L-1, for E2, and between 0.22 and 1500 ng L-1, for EE2. The influence of organic matter, both in the extraction and quantification, was evaluated and it was observed that its presence in the solution did not affect considerably the calibration curve. Recovery rates were also determined, ranging from 77% to 106% for ultrapure water and from 104% to 115% for waste water samples, the most complex ones in what concerns matrix effects. Results obtained when applying the proposed method to real water samples can be considered quite satisfying. Moreover, the obtained working ranges encompass values generally reported in literature, confirming the practical use of the method for environmental samples.