UNIVERSITY OF PADUA DEPARTMENT OF INDUSTRIAL ENGINEERING Master Thesis in Environmental Engineering DEVELOPMENT OF AN ECOSYSTEM MODEL OF THE LOWER PO RIVER FOR USE IN RISK ASSESSMENT OF XENOBIOTICS Main supervisor: Student: Prof. Luca Palmeri * Laura Grechi Co-supervisors: Dr. Alberto Barausse * Dr. Antonio Franco # Dr. Alberto Pivato + *Environmental Systems Analysis Lab – LASA, Department of Industrial Engineering, University of Padua, Italy. # Safety and Environmental Assurance Centre - SEAC, Unilever, Bedfordshire, UK. +Environmental Engineering Group, Department of Industrial Engineering, University of Padua, Italy. Academic Year 2013-2014 "Essentially, all models are wrong, but some are useful" George E. P. Box Abstract Risk assessment methodology at the base of EU environmental directives (Water Framework Directive 2000/60/EC and REACH - Registration, Evaluation and Authorisation of CHemicals directive (EC) No 1907/2006) consists in the calculation of the Risk Quotient (RQ), that is the ratio between Predictive Environmental Concentration (PEC), calculated with fugacity and/or transport models, and Predictive Non Effect Concentration (PNEC) calculated on the basis of standardized eco- toxicological laboratory test, extrapolating individual effects to effects on the ecosystem by using assessment factors that can have a value between 5 to 1000 depending on the ecotoxicological knowledge. This approach is the one most favoured at present but, in spite of being developed in great detail by the European Commission, it is somewhat simplistic and further development to take better account of ecosystem complexity is to be expected [II]. The weakness of this index lies in the fact that PNEC refers to direct effects on a specific organism studied in laboratory and, even if it is a conservatory approach, information about indirect effects of a chemical along the trophic web are neglected. According to these considerations, in this thesis work, a modelling approach to the aquatic risk assessment is considered, trying to mathematically simulate with AQUATOX (US-EPA) software the fate and effects of particular chemicals (Triclosan and LAS - Linear Alkylbenzene Sulfonate) contained in home and personal care products released in the aquatic environment of the largest Italian river, the Po river, with particular focus on the food web simulation. A control ecosystem (with no chemicals) is developed and calibrated with observed data. The ecosystem control model is then used to test changes in organisms biomasses due to different input concentrations of the two chemicals LAS and Triclosan. Problems encountered in the thesis work regard mainly the lack of observed data on Po river biota. To improve the model, a better quantitative knowledge of organisms biomass variation in time and of organisms diet is needed. The results validate the thesis idea that chemical effects on organisms cannot be attributed only to individual toxicity effects (expressed with LC50 and EC50 toxicity parameters) but also to biota interactions with the entire ecosystem (indirect effects). The ecotoxicological model of the Po river developed in this thesis can be considered as a draft useful for future development in order to reach the broader objective to built an ecotoxicological modelling of the Po river based on accurate observed data with the potential to became a tool for the achievement of protection aims and requirements of the chemical and environmental directives of the EU. 1 2 Index Abstract --------------------------------------------------------------------------------------------------- 1 Acknowledgements ------------------------------------------------------------------------------------ 7 1 Introduction --------------------------------------------------------------------------------------- 9 1.1 Overview ------------------------------------------------------------------------------------- 9 1.2 Background -------------------------------------------------------------------------------- 11 1.2.1 State of the art on risk assessment methodologies in Europe ---------- 11 1.2.2 Case studies background --------------------------------------------------------- 13 1.3 Objectives ---------------------------------------------------------------------------------- 13 1.3.1 Thesis objectives and work procedure ---------------------------------------- 13 1.3.2 Broader modelling study objectives ------------------------------------------- 14 2 Materials and methods ----------------------------------------------------------------------- 15 2.1 Modelling tool: AQUATOX program ------------------------------------------------- 15 2.1.1 Model conceptualization and data needed ---------------------------------- 15 2.1.2 Temporal resolution and numerical stability -------------------------------- 17 2.1.3 Calibration strategy ---------------------------------------------------------------- 18 2.1.4 Sensitivity analysis ----------------------------------------------------------------- 21 2.1.5 Validation strategy ----------------------------------------------------------------- 21 2.2 Study area ---------------------------------------------------------------------------------- 22 2.3 River segment morphology ------------------------------------------------------------ 25 2.3.1 Segment length --------------------------------------------------------------------- 25 2.3.2 Segment width ---------------------------------------------------------------------- 26 2.3.3 Surface area ------------------------------------------------------------------------- 26 2.3.4 Channel slope ----------------------------------------------------------------------- 27 2.3.5 Altitude ------------------------------------------------------------------------------- 27 2.3.6 Channel roughness ---------------------------------------------------------------- 27 2.3.7 Bottom surface composition ---------------------------------------------------- 27 2.4 River segment hydrology --------------------------------------------------------------- 30 2.4.1 Flow rate ----------------------------------------------------------------------------- 30 2.4.2 Water depth and bathymetric approximations ----------------------------- 31 2.4.3 Water volume ----------------------------------------------------------------------- 33 3 2.5 Study area climate ------------------------------------------------------------------------ 34 2.5.1 Latitude ------------------------------------------------------------------------------- 34 2.5.2 Wind loadings ------------------------------------------------------------------------ 34 2.5.3 Light loadings ------------------------------------------------------------------------ 35 2.6 Water physico-chemical properties -------------------------------------------------- 36 2.6.1 Water temperature ---------------------------------------------------------------- 36 2.6.2 Water pH ------------------------------------------------------------------------------ 36 2.6.3 Dissolved oxygen -------------------------------------------------------------------- 37 2.6.4 Carbon dioxide ---------------------------------------------------------------------- 38 2.6.5 Nitrogen ------------------------------------------------------------------------------- 38 2.6.6 Phosphorous ------------------------------------------------------------------------- 39 2.6.7 Detritus -------------------------------------------------------------------------------- 40 2.6.8 Inorganic solids ---------------------------------------------------------------------- 42 2.7 Biota ------------------------------------------------------------------------------------------ 43 2.7.1 Plants ---------------------------------------------------------------------------------- 46 2.7.2 Zooplankton -------------------------------------------------------------------------- 54 2.7.3 Macroinvertebrates ---------------------------------------------------------------- 59 2.7.4 Fishes ---------------------------------------------------------------------------------- 66 2.7.5 Food web ----------------------------------------------------------------------------- 77 2.8 Organic chemicals properties ---------------------------------------------------------- 92 2.8.1 LAS -------------------------------------------------------------------------------------- 93 2.8.1.1 Physico-chemical properties -------------------------------------------------- 94 2.8.1.2 Degradation properties -------------------------------------------------------- 95 2.8.1.3 Bioconcentration ---------------------------------------------------------------- 97 2.8.1.4 Ecotoxicological data --------------------------------------------------------- 101 2.8.1.5 Loads and concentration ----------------------------------------------------- 105 2.8.2 Triclosan----------------------------------------------------------------------------- 109 2.8.2.1 Physico-chemical properties ------------------------------------------------ 110 2.8.2.2 Degradation properties ------------------------------------------------------ 111 2.8.2.3 Bioconcentration -------------------------------------------------------------- 112 2.8.2.4 Ecotoxicological data --------------------------------------------------------- 113 2.8.2.5 Loads and concentration ----------------------------------------------------- 115 2.9 Initial conditions, input loadings and chemical scenarios -------------------- 117 4 2.10 Ecological risk assessment indicators ----------------------------------------------118 3 Results -------------------------------------------------------------------------------------------123