Simultaneous removal of a cationic and an anionic textile dye from water by a mixed sorbent of vermicompost and Persian charred dolomite.

The potential of a mixed sorbent consisting of vermicompost and Persian charred dolomite for simultaneous adsorption of Basic Violet 16 (BV16) and Reactive Red 195 (RR195) was investigated. First-order derivative spectrophotometry was used for simultaneous analysis of the two dyes. In single dye experiments, the maximum adsorption capacity of vermicompost for BV16 was found to be 16 mg g-1 and the adsorption capacity of charred dolomite for RR195 was 7.3 mg g-1. Anionic RR195 was not noticeably adsorbed by vermicompost (negative surface charge) and cationic BV16 not by charred dolomite (positive surface charge) but adsorbed by the oppositely charged adsorbents which indicates a selective electrostatic adsorption mechanism. In binary dye solution, BV16 adsorption onto charred dolomite was increased in the presence of RR195 (synergistic effect), yet RR195 adsorption on charred dolomite was not influenced by BV16. An antagonistic effect of RR195 was concluded for BV16 adsorption onto vermicompost. The adsorption equilibrium data for both adsorbents fitted more acceptable to the Langmuir isotherm model than to the Freundlich model in single and binary solutions, but other than the adsorption of BV16 on vermicompost in binary solution which followed the Freundlich model. More than 50% of the removal efficiencies determined for both dyes onto the mixed sorbents were >70% which highlights that the mixed sorbent investigated is highly efficacious for the simultaneous removal of cationic and anionic dyes from contaminated groundwater. Eight cycles reusing vermicompost with 1 N NaOH for regeneration demonstrates the practicability and economic advantage of this natural biosorbent.

Organophosphonates: A review on environmental relevance, biodegradability and removal in wastewater treatment plants.

The worldwide increasing consumption of the phosphonates 2-phosphonobutane-1,2,4-tricarboxylic acid [PBTC], 1-hydroxyethane 1,1-diphosphonic acid [HEDP], nitrilotris(methylene phosphonic acid) [NTMP], ethylenediamine tetra(methylene phosphonic acid) [EDTMP] and diethylenetriamine penta(methylene phosphonic acid) [DTPMP] over the past decades put phosphonates into focus of environmental scientists and agencies, as they are increasingly discussed in the context of various environmental problems. The hitherto difficult analysis of phosphonates contributed to the fact that very little is known about their concentrations and behavior in the environment. This work critically reviews the existing literature up to the year 2016 on the potential environmental relevance of phosphonates, their biotic and abiotic degradability, and their removal in wastewater treatment plants (WWTPs). Accordingly, despite their stability against biological degradation, phosphonates can be removed with relatively high efficiency (>80%) in WWTPs operated with chemical phosphate precipitation. In the literature, however, to our knowledge, there is no information as to whether an enhanced biological phosphorus removal alone is sufficient for such high removal rates and whether the achievable phosphonate concentrations in effluents are sufficiently low to prevent eutrophication. It is currently expected that phosphonates, although being complexing agents, do not remobilize heavy metals from sediments in a significant amount since the phosphonate concentrations required for this (>50µg/L) are considerably higher than the concentrations determined in surface waters. Various publications also point out that phosphonates are harmless to a variety of aquatic organisms. Moreover, degradation products thereof such as N-(phosphonomethyl)glycine and aminomethylphosphonic acid are regarded as being particularly critical. Despite their high stability against biological degradation, phosphonates contribute to eutrophication due to abiotic degradation (mainly photolysis). Furthermore, the literature reports on the fact that phosphonates in high concentrations interfere with phosphate precipitation in WWTPs. Thus, it is recommended to remove phosphonates, in particular from industrial wastewaters, before discharging them into water bodies or WWTPs.

Occurrence and fate of synthetic musk fragrances in a small German river.

The polycyclic musks tonalide(®) (acetyl hexamethyltetraline=1-(3,5,5,6,8,8-hexamethyl-6,7-dihydronaphthalen-2-yl)ethanone, AHTN), galaxolide(®) (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyrane, HHCB) and the degradation product HHCB-lactone were determined in water samples and brown trouts (Salmo trutta fario) of the river Ammer, a small catchment in the state of Baden-Württemberg, south-west Germany. The Ammer receives the effluent discharge of two municipal wastewater treatment plants (WWTPs) with 90,000 population equivalents. The wastewater contributes 14% of the total discharge of the river (average 1.0m(3)/s). Water samples were collected monthly at 12 sampling points from June 2010 to May 2011. Downstream the WWTPs the median concentrations of HHCB, AHTN and HHCB-lactone were 0.26 µg/L, 0.06 µg/L and 1.0 µg/L, respectively. The effluent of the WWTPs was identified as main source of the synthetic musks in the surface water. The ratio of HHCB-lactone/HHCB showed significant seasonal variations indicating the influence of the water temperature on the degradation of HHCB in the surface water. A total of 251 trout was caught in two campaigns in October 2010 at 12 sampling points. The median concentrations of HHCB and AHTN in the trouts downstream the WWTPs significantly increased to 10.8µg/g lipid weight (LW) and 3.7 µg/g LW, respectively.

Estrogenic activity of constituents of underarm deodorants determined by E-Screen assay.

The purpose of this study was to ascertain whether different kinds of underarm deodorants commercially available in Germany might contain substances with estrogenic potential which after use enter the aquatic environment via wastewater. Twenty five deodorants produced by ten different manufacturers in the form of sprays, roll-ons and sticks were investigated using an in vitro-test system (E-Screen assay) for the determination of estrogenic activity based on the human breast cancer cell line MCF-7. Seven out of ten spray deodorant samples showed a quantifiable estrogenic activity. In the case of the sticks and roll-ons it was only one out of six and one out of nine, respectively. The 17ß-estradiol equivalent concentrations (EEQs) of the samples ranged from 0.1 ng g(-1) to 9 ng g(-1) deodorant. Spray deodorant samples showed the highest activities in the E-Screen assay compared to the stick and roll-on deodorants. In order to identify substances possibly contributing to the observed biological activity the samples were additionally analyzed by GC/MS. The obtained results of this non-target screening led to the selection of 62 single substances present in the deodorants which for their part were analyzed by E-Screen assay. Eight of these single substances, all of them fragrances, showed estrogenic effects with estradiol equivalence factors (EEFs) similar to parabens, a group of 4-hydroxybenzoic acid esters commonly used as preservatives in personal care products, which are known to have a slight estrogenic effect. Thus, these fragrances are obviously responsible to a substantial degree for the observed estrogenic activity of the deodorants.

Effect-related monitoring: estrogen-like substances in groundwater.

BACKGROUND, AIM, AND SCOPE: Concentration monitoring as a basis for risk assessment is a valid approach only if there is an unambiguous relation between concentration and effect. In many cases, no such unambiguous relation exists, since various substances can exert the same effect with differing potencies. If some or all of these substances contributing to a biological effect are unknown, effect-related monitoring becomes indispensable. Endocrine-disrupting substances in water bodies, including the groundwater, are a prominent example of such a case. The aim of the investigations described here was to detect hormonally active substances in the groundwater downstream of obsolete landfills by using the E-screen assay and to possibly assign the biological effect to individual chemical compounds by means of instrumental analyses carried out in parallel. MATERIALS AND METHODS: Grab samples of the groundwater were collected downstream from abandoned landfills and prepared by liquid/liquid extraction. The total estrogenic activity in these samples was determined in vitro by applying the E-screen assay. The human breast cancer cells (MCF-7) used in the E-screen proliferate in response to the presence of estrogenically active compounds. Expressed in concentration units of the reference substance 17beta-estradiol (E2), the test system allows the quantification of estrogenicity with a limit of detection (LOD) in the range of 0.1 ng/L. Aliquots of the samples were screened using gas chromatography/mass spectrometry (GC/MS) in order to quantify known estrogenically active substances and to identify unknown compounds. Estrogen-positive samples were extracted at different pH values, split into acidic, neutral, and basic fractions and analyzed by GC/MS, searching for individual components that display estrogenic activity. RESULTS AND DISCUSSION: Estrogenic activity exceeding the LOD and the provisional benchmark of 0.5 ng E2/L was found at three out of seven abandoned waste disposal sites tested. The low concentrations of known xenoestrogens such as bisphenol-A, nonylphenols, or phthalic acid esters determined by GC/MS, however, were not sufficient to explain the detected activity. Neither natural nor synthetic hormones have caused the activity because these chemical structures are readily degradable and cannot persist in abandoned landfills for decades. The highest activity in the E-screen assay was found in the acidic fractions. Hydroxypolychlorinated biphenyls (PCBs), hydroxylated polycyclic aromatic hydrocarbons (PAHs) and hetero-PAHs, as well as alkylphenols could be identified as further compounds with possible hormonal activity. CONCLUSIONS: Estrogenically active substances may occur in the groundwater below obsolete landfills, especially those that contain PCBs or waste from gasworks. These substances are not part of analytical programs routinely applied to contaminated sites and may therefore escape detection and assessment. Analyses using the E-screen assay and GC/MS in parallel have shown that the total estrogenic activity found in groundwater samples is to be ascribed to a multitude of individual compounds, some of which cannot be quantified due to lack of standard substances or assessed due to lack of a standardized procedure for determination of their estrogenic potency. By comparison with provisional guide values for estradiol (0.5 ng/L) and ethynylestradiol (0.3 ng/L), the damaging potential of the total estrogenic activity in groundwater samples can in fact be assessed, but specific remediation measures are impossible unless the hormonal activity can be attributed to individual chemical substances. RECOMMENDATIONS AND OUTLOOK: On the one hand, further analyses of samples taken from possible pollution sources should be conducted in order to characterize the extent of groundwater pollution with xenoestrogens. On the other hand, the most potent individual compounds should be identified according to their estrogenic potency. To this end, bioassay-directed fractionation and structure elucidation should be carried out with concentrated samples.

Aerobic biodegradability of the calcium channel antagonist verapamil and identification of a microbial dead-end transformation product studied by LC-MS/MS.

In recent years pharmaceuticals and personal care products have been detected in increasing concentrations in hospital effluents, sewage treatment plants (STP) as well as in different environmental compartments such as surface water, groundwater and soil. Little is known about the elimination of these substances during sewage treatment or about the formation of potential metabolites in the environment caused by bacterial biotransformation. To assess the biodegradability of the popular cardiovascular drug verapamil and the possible formation of potential microbial degradation products, two tests from the OECD series were used in the present study: the widely used Closed Bottle test (OECD 301 D) and the modified Zahn-Wellens test (OECD 302 B). In the Closed Bottle test, a screening test that simulates the conditions of an environmental surface water compartment, no biological degradation was observed for verapamil at concentrations of 2.33mgl(-1). In the Zahn-Wellens test, a test for inherent biodegradability which allows evaluation of aerobic degradation at high bacterial density, only a partial biological degradation was found. Analysis of test samples by high performance liquid chromatography coupled to multiple stage mass spectrometry (HPLC-MSn) revealed 2-(3,4-dimethoxyphenyl)-2-isopropyl-5-(methylamino)pentane nitrile, already known as D617 (Knoll nomenclature), a metabolite of mammalian metabolism, which is the major degradation product and dead-end transformation product of aerobic degradation of verapamil.

Brominated-chlorinated diphenyl ethers formed by thermolysis of polybrominated diphenyl ethers at low temperatures.

Polybrominated diphenyl ethers (PBDEs) are a group of brominated flame retardants (BFRs) used mainly as additives in different kinds of plastic material. Various PBDEs are found in all environmental compartments as well as in tissue and blood serum of animals and humans due to their persistence and tendency to bioaccumulate. Emission of PBDEs into the environment can occur during recycling of PBDE-containing plastic material or during their uncontrolled or insufficient combustion as e.g. in accidental fires or landfill fires. Under these circumstances, PBDEs can also function as precursor molecules for the formation of polybrominated dibenzodioxins (PBDDs) and dibenzofurans (PBDFs). In this study, we qualitatively investigated the reaction of two PBDE congeners, 2,2',4,4'-tetrabromo diphenyl ether (BDE 47) and 2,2',4,4',5,5'-hexabromo diphenyl ether (BDE 153), as well as hexabromobenzene (HBB), a flame retardant used in the past, when exposed to temperatures between 250 degrees C and 500 degrees C. The formed reaction products were analysed by high resolution gas chromatography-low resolution mass spectrometry (HRGC-LRMS). Among others brominated-chlorinated diphenyl ethers were formed by chlorodebromination of the PBDEs. In addition, thermolysis of BDE 47 and BDE 153 in the presence of tetrachloromethane as model substance for an organic chlorine source was studied. Thermal treatment of HBB resulted in the formation of brominated-chlorinated benzenes.

On sensitivity, specificity, and the influence of various parameters on ethyl glucuronide levels in urine--results from the WHO/ISBRA study.

BACKGROUND: Ethyl glucuronide (EtG), a direct ethanol metabolite, seems to meet the need for a sensitive and specific marker for monitoring recent alcohol consumption in different settings. Our aim was to study sensitivity, specificity, and the influence of various parameters on EtG levels in urine. PATIENTS AND METHODS: Urine samples for a total of 453 patients (373 male, 80 female) were statistically analyzed. The mean age was 37.1 years (median 36, SD 12.59), body mass index was 24.7, total ethanol consumed last month was 1817.66 g (each median), and 80 patients reported cannabis use within the last 30 days. Determination of EtG was performed with a liquid chromatography-tandem mass spectrometry method with deuterium-labeled EtG as internal standard. RESULTS: For EtG in urine, a good correlation was found with other state markers and days of sobriety. In a regression analysis, age, gender, marijuana use, kidney disease, and total grams of ethanol consumed last month were the variables that significantly influenced EtG levels in contrast to race, smoking, body mass index, cirrhosis of liver, age began drinking regularly, packs of cigarettes smoked last month, and total body water. Furthermore, in a receiver operating characteristic curve analysis to distinguish between nondrinkers and individuals sober > 4 days versus individuals drinking in the recent 4 days, area under the curve was 0.834. At a cutoff of 0.145 mg/liter, sensitivity was 83.5% and specificity 68.3%. A receiver operating characteristic curve was calculated for lifetime alcohol abuse or dependence against those who had never been abusers or dependent. In this case, subjects were either never dependent or lifetime dependent, but those currently dependent were excluded. The resulting area under the curve was 0.694. At a cutoff of 0.145 mg/liter, sensitivity was 73.8% and specificity 60.3%. For those with a self-reported sobriety of less than 24 hr, the area under the curve was 0.899, sensitivity was 90.8%, and specificity was 76.5% at a cutoff of 0.435 mg/liter when we calculated nondrinkers and light drinkers against heavy drinkers and drinkers needing treatment. Cannabis-using patients showed significant differences with regard to almost all state markers when compared with nonconsuming subjects. CONCLUSIONS: Age, gender, marijuana use, kidney disease, and total grams of ethanol consumed last month should be taken into consideration when interpreting results of EtG in urine. Sensitivity and specificity seem promising. Cannabis use can be regarded as an indicator for other serious mental problems in alcohol-using subjects.

Interaction of xenin with the neurotensin receptor of guinea pig enteral smooth muscles.

Xenin, a 25 amino acid peptide, interacts with the neurotensin receptor subtype 1 of intestinal muscles of the guinea pig. Replacement of the C-terminal Lys-Arg peptide bond in xenin 6 by a reduced pseudo-peptide bond augmented binding affinity to isolated jejunal and colonic muscle membranes by factors of 7.7 and 21.0 respectively; the potency to contract the jejunum and to relax the colon was increased by factors of 3.2 and 1.3. The C-terminus Trp-Ile-Leu (WIL) of xenin, in contrast to the C-terminus Tyr-Ile-Leu (YIL) of neurotensin, bound competitively to the muscle membranes. WIL blocked the contractile action of xenin in the jejunum and was synergistic with the relaxing action in the colon. The Lys-Arg motif and Trp in the C-terminus of xenin are essential structures in the action of xenin on the enteral smooth muscle receptors.

Interaction of xenin with the neurotensin receptor of guinea pig enteral smooth muscles.

Xenin, a 25 aminoacid peptide, interacts with the neurotensin receptor subtype 1 of intestinal muscles of the guinea pig. Replacement of the C-terminal Lys -Arg peptide bond in xenin 6 by a reduced pseudo-peptide bond augmented binding affinity to isolated jejunal and colonic muscle membranes by factors of 7.7 and 21.0 respectively; the potency to contract the jejunum and to relax the colon was increased by factors of 3.2 and 1.3. The C-terminus Trp-Ile-Leu (WIL) of xenin, in contrast to the C-terminus Tyr-Ile-Leu (YIL) of neurotensin, bound competitively to the muscle membranes. WIL blocked the contractile action of xenin in the jejunum and was synergistic with the relaxing action in the colon. The Lys -Arg motif and Trp in the C-terminus of xenin are essential structures in the action of xenin on the enteral smooth muscle receptors.