Occurrence and temporal variations of TMDD in the river Rhine, Germany

Background, aim, and scope: The chemical substance 2,4,7,9-tetramethyl-5-decyne-4,7-diol (TMDD) is a non-ionic surfactant used as an industrial defoaming agent and in various other applications. Its commercial name is Surynol 104® and the related ethoxylates are also available as Surfynol® 420, 440, 465 and 485 which are characterized by different grades of ethoxylation of TMDD at both hydroxyl functional groups. TMDD and its ethoxylates offer several advantages in waterborne industrial applications in coatings, inks, adhesives as well as in paper industries. TMDD and its ethoxylates can be expected to reach the aquatic environment due its widespread use and its physico-chemical properties. TMDD has previously been detected in several rivers of Germany with concentrations up to 2.5 µg/L. In the United States, TMDD was also detected in drinking water. However, detailed studies about its presence and distribution in the aquatic environment have not been carried out so far. The aim of the present study was the analysis of the spatial and temporal concentration variations of TMDD in the river Rhine at the Rheingütestation Worms (443.3 km). Moreover, the transported load in the Rhine was investigated during two entire days and 7 weeks between November 2007 and January 2008. Materials and methods: The sampling was carried out at three different sampling points across the river. Sampling point MWL1 is located in the left part of the river, MWL2 in the middle part, and MWL4 in the right part. One more sampling site (MWL3) was run by the monitoring station until the end of 2006, but was put out of service due to financial constrains. The water at the left side of the river Rhine (MWL1) is influenced by sewage from a big chemical plant in Ludwigshafen and by the sewage water from this city. The water at the right side of the river Rhine (MWL4) is largely composed of the water inflow from river Neckar, discharging into Rhine 14.9 km upstream from the sampling point and of communal and industrial wastewater from the city Mannheim. The water from the middle of the river (MWL2) is largely composed of water from the upper Rhine. Water samples were collected in 1-L bottles by an automatic sampler. The water samples were concentrated by use of solid-phase extraction (SPE) using Bond Elut PPL cartridges and quantified by use of gas chromatography-mass spectrometry (GC-MS). The quantification was carried out with the internal standard method. Based on these results, concentration variations were determined for the day profiles and week profiles. The total number of analyzed samples was 219. Results: The results of this study provide information on the temporal concentration variability of TMDD in river Rhine in a cross section at one particular sampling point (443.3 km). TMDD was detected in all analyzed water samples at high concentrations. The mean concentrations during the 2 days were 314 ng/L in MWL1, 246 ng/L in MWL2, and 286 ng/L in MWL4. The variation of concentrations was low in the day profiles. In the week profiles, a trend of increasing TMDD concentrations was detected particularly in January 2008, when TMDD concentrations reached values up to 1,330 ng/L in MWL1. The mean TMDD concentrations during the week profiles were 540 ng/L in MWL1, 484 ng/L in MWL2, and 576 ng/L in MWL4. The loads of TMDD were also determined and revealed to be comparable in all three sections of the river. The chemical plant located at the left side of the Rhine is not contributing additional TMDD to the river. The load of TMDD has been determined to be 62.8 kg/d on average during the entire period. By extrapolation of data obtained from seven week profiles the annual load was calculated to 23 t/a. Discussion: The permanent high TMDD concentrations during the investigation period indicate an almost constant discharge of TMDD into the river. This observation argues for effluents of municipal wastewater treatment plants as the most likely source of TMDD in the river. Another possible source might be the degradation of ethoxylates of TMDD (Surfynol® series 400), in the WWTPs under formation of TMDD followed by discharge into the river. TMDD has to be considered as a high-production-volume (HPV) chemical based on the high concentrations found in this study. In the United States, TMDD is already in the list of HPV chemicals from the Environmental Protection Agency (EPA). However, the amount of TMDD production in Europe is unknown so far and also the biodegradation rates of TMDD in WWTPs have not been investigated. Conclusions: TMDD was found in high concentrations during the entire sampling period in the Rhine river at the three sampling points. During the sampling period, TMDD concentrations remained constant in each part of the river. These results show that TMDD is uniformly distributed in the water collected at three sampling points located across the river. ‘Waves’ of exceptionally high concentrations of TMDD could not be detected during the sampling period. These results indicate that the effluents of WWTPs have to be considered as the most important sources of TMDD in river Rhine. Recommendations and perspectives: Based also on the occurrence of TMDD in different surface waters of Germany with concentrations up to 2,500 ng/L and its presence in drinking water in the USA, more detailed investigations regarding its sources and distribution in the aquatic environment are required. Moreover, the knowledge with respect to its ecotoxicity and its biodegradation pathway is scarce and has to be gained in more detail. Further research is necessary to investigate the rate of elimination of TMDD in municipal and industrial wastewater treatment plants in order to clarify the degradation rate of TMDD and to determine to which extent effluents of WWTPs contribute to the input of TMDD into surface waters. Supplementary studies are needed to clarify whether the ethoxylates of TMDD (known as Surfynol 400® series) are hydrolyzed in the aquatic environment resulting in formation of TMDD similar to the well known cleavage of nonylphenol ethoxylates into nonylphenols. The stability of TMDD under anaerobic conditions in groundwater is also unknown and should be studied

Effect-Directed Analysis of Municipal Landfill Soil Reveals Novel Developmental Toxicants in the Zebrafish Danio rerio

Effect-directed analysis (EDA) is an approach used to identify (unknown) contaminants in complex samples which cause toxicity, using a combination of biology and chemistry. The goal of this work was to apply EDA to identify developmental toxicants in soil samples collected from a former municipal landfill site. Soil samples were extracted, fractionated, and tested for developmental effects with an embryotoxicity assay in the zebrafish Danio rerio. Gas chromatograph mass selective detection (GC-MSD) chemical screening was used to reveal candidate developmental toxicants in fractions showing effects. In a parallel study, liquid chromatography-hybrid linear ion trap Orbitrap mass spectrometry was also applied to one polar subfraction (Hoogenboom et al. J. Chromatogr. A2009, 1216, 510-519). EDA resulted in the identification of a number of previously unknown developmental toxicants, which were confirmed to be present in soil by GC-MS. These included 11H-benzo[b]fluorene, 9-methylacridine, 4-azapyrene, and 2-phenylquinoline, as well as one known developmental toxicant (retene). This work revealed the presence of novel contaminants in the environment that may affect vertebrate development, which are not subject to monitoring or regulation under current soil quality assessment guidelines. © 2011 American Chemical Society

Copper, zinc, mercury and arsenic content in Micropogonias furnieri and Mugil platanus of the Montevideo coastal zone, Río de la Plata

Abstract Metals (Cu, Zn, Hg) and metalloid (As) concentrations were measured in Micropogonias furnieri and Mugil platanus caught in three areas along the Montevideo coastal zone during winter 2010, spring 2010 and 2011. Compared to previous studies conducted in the zone, both species showed higher (for Cu), similar (for Zn) or lower (for Hg) concentrations. The highest Hg values were found in the M. furnieri of Montevideo bay. There was no spatial variation in Cu, Zn, and As concentrations in muscle, likely due to the high mobility of both species. However, the Cu content in the liver of M. furnieri was higher in fish from the West zone. Cu, Zn and As found in the liver of M. platanus were much higher than in that of M. furnieri. A functional relationship between muscle levels of Zn and Hg and fish length of M. furnieri indicates bioaccumulation of these metals. According to the results, M. furnieri may be used as a temporal bioindicator for Hg, but not as a spatial bioindicator. Mercury levels were below the maximum safety level based on international standard values for human consumption

BIGSET. Teilprojekt 4: Das Erhaltungspotential der primaeren Klima- und Umweltsignale in der Tiefsee Abschlussbericht

Regional and seasonal variations of upper ocean productivity can be discerned as variations in fluxes of particulate organic carbon (C_o_r_g) to the deep sea. The coupling between C_o_r_g-fluxes and benthic processes could therefore result in regional and seasonal variations of the carbon cycle in the deep sea. Settling particles carry also signals of upper ocean biogeochemical processes such as the stable isotopic composition of nitrogen (#delta#"1"5N) and organic carbon (#delta#"1"3C) to the deep sea. They are used to decipher paleoceanographic processes although the modification of the #delta#"1"5N- and #delta#"1"3C-values during sedimentation is unknown. For the determination of C_o_r_g-fluxes and for the research on early diagenesis of organic carbon and its influence on the modification of the stable isotopic composition, settling particles, sediments and pore waters were sampled during two cruises each in the Arabian Sea and in the NE-Atlantic. For the collection of settling particles moorings with a sediment trap at approximately 500 m above the sea floor were deployed for 2-24 days. Particle fluxes and C_o_r_g-fluxes show regional and seasonal variations which are in agreement with regional and seasonal variations of surface productivity. (orig.)Regionale und saisonale Schwankungen der Oberflaechenproduktivitaet im Ozean koennen als Variationen der Flussrate organischen Kohlenstoffs (C_o_r_g) in die Tiefsee verfolgt werden. Die Kopplung zwischen C_o_r_g-Flussrate und benthischen Prozessen kann daher zu regionalen und saisonalen Schwankungen des Kohlenstoffkreislaufes in der Tiefsee fuehren. Absinkende Partikel tragen auch Signale von biogeochemischen Ozeanoberflaechenprozessen, wie die Isotopenzusammensetzung des Stickstoffs (#delta#"1"5N) und des organischen Kohlenstoffs (#delta#"1"3C), in die Tiefsee. Sie werden dazu genutzt palaeoozeanographische Prozesse zu entschluesseln, obwohl noch Unklarheit ueber die Modifikation der #delta#"1"5N- und #delta#"1"3C-Werte bei der Sedimentation besteht. Fuer die Bestimmung der C_o_r_g-Flussrate und fuer die Untersuchung der Fruehdiagnose organischen Kohlenstoffs und ihre Auswirkung auf die Modifikation stabiler Isotopenzusammensetzungen wurden auf jeweils zwei Forschungsfahrten im Arabischen Meer und im NO-Atlantik Sinkstoff-, Sediment- und Porenwasserproben gesammelt. Die Beprobung der Sinkstoffe erfolgte mit Hilfe von Sinkstoffallen, die fuer 2-24 Tage in etwa 500 m ueber Grund verankert waren. Fuer den Partikelfluss und damit auch fuer den C_o_r_g-Eintrag in die bodennahe Grenzschicht wurden regionale und saisonale Unterschiede gefunden, die mit den bekannten regionalen und saisonalen Variationen der Oberflaechenproduktivitaet uebereinstimmen. Diese regionalen und saisonalen Schwankungen der C_o_r_g-Eintragsraten stimmen in etwa mit den Variationen der mikrobiellen Biomasse und Aktivitaet im Sediment ueberein. (orig.)Available from TIB Hannover: F01B59 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman