metal(loid)s, nanomaterials & the transfer/transformation in wetlands ... The presentation will provide a broad overview on metal and metalloid emerging ...
Wastewater, examples on new organic contaminants, upcoming metal(loid)s, nanomaterials & the transfer/transformation in wetlands Lars Duestera, Bjoern Meermanna, Anne-Lena Fabriciusa, Michael Schluesenera and Thomas A. Ternesa a
Federal Institute of Hydrology, Department G2 - Aquatic Chemistry, Am Mainzer Tor 1, 56068 Koblenz, Germany
KEYNOTE The presentation will provide a broad overview on metal and metalloid emerging pollutants1 which are used in “new” industrial applications as well as on organic compounds/particles that are under discussion to induce adverse environmental effects in close to nature and constructed wetlands. The release scenarios and factors that impact the environmental fate and transformation of potential pollutants will be addressed within the presentation (figure. 1).
Figure 1: The four central themes and connecting links of the presentation.
I. “NEW” METAL(LOID)S At a first glance and compared to the magnitude of man-made organic compounds that show a potential to cause adverse environmental effects, inorganic compounds seem to have a lower innovation potential in industrial application. This impression may change as soon as one begins to think about speciation, fractionation2 and the availability of metals or metalloids (metal(loid)s). Hence, for some metal(loid)s the occurrence of: 1. “new” metal(loid) organic species, 2. “new” fractions, e.g., nanoparticles, 3. or less commonly used metals in “new” industrial/medical applications, is connected with certain concerns. 1
Emerging pollutants: A substance currently not included in routine environmental monitoring programmes and which may be candidate for future legislation due to its adverse effects and / or persistency (http://www.normannetwork.net/index_php.php?module=public/others/glossary#e_pollute). 2 Chemical species: Chemical elements: specific form of an element defined as to isotopic composition, electronic or oxidation state, and/or complex or molecular structure. Fractionation: Process of classification of an analyte or a group of analytes from a certain sample according to physical (e.g., size, solubility) or chemical (e.g., bonding, reactivity) properties (Templeton, Ariese et al. 2000).
As a simple example for point 1, zinc pyrithione is one of the most common biocides used from personal care products to antifouling paints, but at the moment no analytical method is available to allow a precise detection in different environmental matrices. Hence, it is impossible to assess whether there is a risk toward wetlands, e.g., constructed wetlands in water purification, or not. Point 2 is detailed in the next paragraph. Examples for point 3 are the use of Gadolinium in MRTcontrast agents or the use of so far less used metals, nowadays, applied in new technical application like semiconductors (e.g., thallium), micro capacitators (e.g., niob) or in renewable energy applications (e.g., tellurium, germanium, neodymium, table 1). Table 1: Raw material emerging technologies (selected), modified after (EU Commission-Enterprise & Industry 2010). Element Application Antimony micro capacitors Cobalt Lithium-ion batteries, synthetic fuels Gallium Thin layer photovoltaics Germanium Fibre optic cable, IR optical technologies Indium Displays, thin layer photovoltaics Platinum Fuel cells, catalysts Palladium Catalysts, seawater desalination Niobium Micro capacitors, ferroalloys Neodymium Permanent magnets, laser technology Tantalum Micro capacitors, medical technology
For, e.g., technical critical elements, it becomes obvious that mining, the industrial production (waste water) and recycling may pose risks to wetlands via the discharge of waste waters. Especially low-tech recycling in emerging countries has to be considered in this context. II. ENGINEERED NANOMATERIALS Changing from mostly speciation based scientific questions to fractionation based, within the last years concerns on adverse environmental effects from unintentionally released engineered nanomaterials (ENMs) were expressed by scientists (e.g., Wijnhoven, Peijnenburg et al. 2009) and NGOs (etc-group 2010). An overview on nanomaterial definitions can be found at JRC, 2010. A very pragmatic and handy definition on nanomaterials is that these materials hold at least one dimension < 100 nm (e.g., a nano foil). This is sufficient to understand the following considerations: Focusing on nanotubes (two dimensions < 100 nm) as well as nanoparticles (three dimensions < 100 nm) and wetlands, waste waters from industries/household and, hence, effluents from wastewater treatment plants (WTTPs) as well as stormwater can be identified as potentially relevant sources of contamination (figure 2). As most common nanomaterials in industrial applications and consumer products Ag and the oxides of Ce, Fe, Si, Ti and Zn as well as carbon nano tubes (CNTs) were identified (Piccinno, Gottschalk et al. 2012). First results on Ag (Kaegi, Voegelin et al. 2013; Hou, Li et al. 2012), TiO2, SiO2 (Park, Kim et al. 2013) and ZnO (Hou, Xia et al. 2013) show separation efficiencies > 90% from the waste water to the sludge during water treatment. This can be taken as good news for wetlands, but variable process disturbances, like heavy rain events and the release via stormwater, were not sufficiently addressed by now and leave space for uncertainties. Beside challenges in environmental analytical chemistry and ongoing discussions on the transformation of ENMs in WTTPs and in surface water environments, the unknown input quantities from industries were recently identified as a general major drawback in environmental risk assessments on ENMs (Hendren, Mesnard et al. 2012; Piccinno, Gottschalk et al. 2012). With respect to the generally valid precautionary principle, first results on the fate and effects of ENM in wetlands are now available (e.g., (Jacob, Borchardt et al. 2013; Sharif, Westerhoff et al. 2013)).
Figure 2: Pathways and uncertainties in nanomaterial balances of WWTP. The picture shows the Emscher WWTP in Germany (taken from COST Action ENTER ES1205 (http://www.cost.eu/domains_actions/essem/Actions/ES1205)).
III. MICRO AND MACRO PLASTICS After and in parallel to a certain “nano–hype” in different scientific disciplines and also in environmental sciences, the public and the scientific community were put on alert, by environmental activists and by NGOs (e.g., http://plasticsoupfoundation.org/eng/beat-the-microbead/), for a further group of particles – primary and secondary plastic particles. First indicators and working areas was an increasing contamination of the oceans and shorelines with plastics. In this context, primary particles are present in the size they were produced by industries and secondary particles are products of weathering and fragmentation of bigger plastic pieces (figure 3). With the rising awareness on environmental adverse effects from plastics in the marine environment the amount of publications addressing this issue in marine (which started ~ in the late 1980s (Liebezeit and Dubaish 2012) ) and, newly, freshwater environments (Dubaish and Liebezeit 2013), wetlands (Cordeiro and Costa 2010) as well as on quantitative and qualitative analyses of plastics in the environment, is increasing (e.g., (Claessens, Van Cauwenberghe et al. 2013; Hidalgo-Ruz, Gutow et al. 2012; Imhof, Schmid et al. 2012)). As an example for a changing public perception and caused by public pressure in the commission decision on criteria and methodological standards on good environmental status of marine waters, in the descriptor 10, micro plastics are addressed (EU Commission 2010). In addition, at the beginning of 2013 Unilever agreed to phase out micro beads from personal care products (The Guardian, 2013).
Figure 3: Examples for primary particles (left: polystyrene micro beads, mean diameter 230 µm in vial) and secondary particles (right: plastic fragments (white spots) < 2 mm - 0.63 µm on a sieve in a freeze dried river sediment, collected down stream a recycling facility in Germany). Micro beads are used in a wide range of applications from lacquer to personal care products.
IV. EMERGING ORGANIC CONTAMINATANTS/MICROPOLLUTANTS In contrast to the first three topics the scientific working area on organic contaminants/micro pollutants and wetlands is dominated by questions on the removal efficiency posed by wetlands by using them as a fourth purification stage in WTTP. Questions on potential adverse effects are less often addressed. Depending on the intensity with which this topic is already addressed in the conference, prior this lecture, the presentation will focus on the degradation and transformation of organic analytes from personal care products and pharmaceuticals as well as on biocides in constructed wetlands. REFERENCES Claessens, M., L. Van Cauwenberghe, et al. (2013) "New techniques for the detection of microplastics in sediments and field collected organisms." Marine Pollution Bulletin 70(1-2): 227-33. Cordeiro, C. A. M. M. and T. M. Costa (2010) "Evaluation of solid residues removed from a mangrove swamp in the Sao Vicente Estuary, SP, Brazil." Marine Pollution Bulletin 60(10): 1762-1767. Dubaish, F. and G. Liebezeit (2013) "Suspended Microplastics and Black Carbon Particles in the Jade System, Southern North Sea." Water Air and Soil Pollution 224(2). etc-group (2010). The Big Downturn? Nanogeopolitics. (http://www.etcgroup.org/fr/node/5245). EU Commission Enterprise&Industry (2010). Critical raw materials for the EU EU Commission (2010) (http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:232:0014:0024:EN:PDF) Hendren, C. O., X. Mesnard, et al. (2012). "Estimating Production Data for Five Engineered Nanomaterials As a Basis for Exposure Assessment." Environmental Science & Technology 45(7): 2562-2569. Hidalgo-Ruz, V., L. Gutow, et al. (2012) "Microplastics in the Marine Environment: A Review of the Methods Used for Identification and Quantification." Environmental Science & Technology 46(6): 3060-3075. Hou, L. L., K. Y. Li, et al. (2012). "Removal of silver nanoparticles in simulated wastewater treatment processes and its impact on COD and NH4 reduction." Chemosphere 87(3): 248-252. Hou, L. L., J. Xia, et al. (2013). "Removal of ZnO nanoparticles in simulated wastewater treatment processes and its effects on COD and NH4+-N reduction." Water Science and Technology 67(2): 254-260. Imhof, H. K., J. Schmid, et al. (2012) "A novel, highly efficient method for the separation and quantification of plastic particles in sediments of aquatic environments." Limnology and Oceanography-Methods 10: 524-537. Jacob, D. L., J. D. Borchardt, et al. (2013). "Uptake and translocation of Ti from nanoparticles in crops and wetland plants." International Journal of Phytoremediation 15(2): 142-153. JRC. (2010) Considerations on a Definition of Nanomaterial for Regulatory Purposes (http://ec.europa.eu/dgs/jrc/downloads/jrc_reference_report_201007_nanomaterials.pdf).
Kaegi, R., A. Voegelin, et al. (2013). "Fate and Transformation of Silver Nanoparticles in Urban Wastewater Systems." Water Research 47(12): 3866–3877. Liebezeit, G. and F. Dubaish (2012). "Microplastics in Beaches of the East Frisian Islands Spiekeroog and Kachelotplate." Bulletin of Environmental Contamination and Toxicology 89(1): 213-217. Park, H. J., H. Y. Kim, et al. (2013). "Removal characteristics of engineered nanoparticles by activated sludge." Chemosphere 92(5): 524-528. Piccinno, F., F. Gottschalk, et al. (2012). "Industrial production quantities and uses of ten engineered nanomaterials in Europe and the world." Journal of Nanoparticle Research 14(9). Sharif, F., P. Westerhoff, et al. (2013). "Sorption of trace organics and engineered nanomaterials onto wetland plant material." Environmental Science: Processes & Impacts 15(1): 267-274. Templeton, D. M., F. Ariese, et al. (2000). "Guidelines for terms related to chemical speciation and fractionation of elements. Definitions, structural aspects, and methodological approaches (IUPAC Recommendations 2000)." Pure and Applied Chemistry 72(8): 1453-1470. The Guardian, 2013; http://www.theguardian.com/environment/2013/jan/09/unilever-plastic-microbeadsfacial-scrubs?CMP=twt_gu) Wijnhoven, S. W. P., W. Peijnenburg, et al. (2009). "Nano-silver - a review of available data and knowledge gaps in human and environmental risk assessment." Nanotoxicology 3(2): 109-U78.
