Reducing PEC uncertainty in coastal zones: a case study on carbamazepine, oxcarbazepine and their metabolites.

Concentrations of the antiepileptic drugs carbamazepine (Cbz), oxcarbazepine (OxCz) and their main metabolites were predicted in a wastewater treatment plant (WTP) and in the vicinity of its submarine outfall located in a Mediterranean coastal zone. Refined predicted environmental concentrations (PECs) were calculated in effluents based on consumption data and human excretion rates. PECs were estimated in the sea using the hydrodynamic MARS 3D model integrating meteorological data, oceanic conditions (wind, tide, atmospheric pressure), freshwater and sewage inputs. Measured environmental concentrations (MECs) were compared to PECs to assess the estimation relevance. In the coastal zone, PEC and MEC were in the same magnitude range. Modeling of Cbz diffusion and advection just above the submarine outfall showed the influence of the thermocline during summer, with low diffusion of Cbz from the bottom to the surface. This work allowed understanding the dispersion of target compounds and deserved further development for a better acknowledgement of vulnerability at local scales.

Why, how, and how far should microbiological contamination in a coastal zone be mitigated? An application of the systems approach to the Thau lagoon (France).

This paper describes the building of an integrated simulation tool based on a systems approach, and its contribution to local political discussion of the mitigation of microbiological contamination of the water in a coastal area. Local management schemes view water quality as a high-priority environmental objective. In practice, how far this objective is achieved depends on trade-offs between the costs of improved water treatment facilities and the acceptable impacts of water contamination. An in-the-field experiment in collaboration with local managers was carried out in the Thau lagoon on the French Mediterranean coast during the SPICOSA (Science and Policy Integration for Coastal System Assessment) project, from 2007 through 2011. It consisted of building a modeling platform and an integrated assessment framework for simulating exploratory scenarios. The modeling platform combines a dynamic contamination model, which represents the sources of microbiological contamination, wastewater treatment facilities, and physical mechanisms of lagoon contamination, with a prospective economic model, which estimates the patterns of development of economic activities in the area through a holistic approach. Exploratory scenarios are used to assess the risk of water contamination and the efficiency of management measures, under various assumptions about the evolution of the system. The contamination simulations suggest that the work currently planned by local authorities will be inadequate for preventing increased water pollution, and that additional but fairly inexpensive management measures for maintaining the current level of water quality should be considered. The integrated assessment framework estimates the ecological and socio-economic impacts of the various pollution mitigation policies in the broader context of possible local development patterns. The results illustrate how the systems approach may aid in the design of an applicable water policy based on operational objectives and feasible technical options.