MariaBox: first prototype of a novel instrument to observe natural and chemical pollutants in seawater

The MariaBox project, funded by the European Commission (Contract 614088), is developing an autonomous, analytical device, based on novel biosensors, for monitoring chemical and biological pollutants in sea water. The device, currently at first prototype level, is suitable for installation in free floating devices, buoys or ships. The main, high-level user requirements for the system are for the device to be of highsensitivity, portable and capable of repeating measurements over a long time, allowing long-term deployment at sea. The first phase of the project, "user requirements collection", was dedicated to understanding the current needs of water monitoring through institutions in different areas of Europe, at different location types. The locations in which the research was focused are also the ones in which the field validation of MariaBox will take place: a sea water lagoon in Spain with different characteristics of water salinity and natural environment, currently exploited for shellfish farming; a natural site in Ireland (Galway bay); the Skagerrak, a sea arm between Norway, Denmark and Sweden; and a harbour area close to industrial facilities in Cyprus. The analytes of interest for the monitoring institutions are coherent to the list of pollutants to be monitored by the European Commission. A first trade-off between end-user requirements and engineering feasibility, available time and final system cost had to be made. On one hand, the MariaBox device is intended to be portable and its size must be such as to allow permanent positioning inside sea buoys. Several modules are required to achieve the aim of monitoring, in an autonomous and unattended way, all selected target analytes for a period of several months. Energy expenditure is a relevant constraint. Nevertheless, being a device deployed at sea, energy scavenging is a real option to guarantee the system autonomy or, at least, to keep the system operating at a minimum level, that is, to maintain the biosensors and the biochemical reactants in a controlled and safe environment. This controlled environment is managed by the analytical core unit of MariaBox, that acts as a cooler or heater depending on the external temperatures (from 10 degrees C up to + 50 degrees C). The system design has been confronted with all of these challenging requirements. The device is intended to provide not only scientific data but also early warnings in relation to both algal blooming and production of toxins, as well as to chemical, man-made pollutants (heavy metals, camphechlor, naphthalene, PFOS). This means that considering the European thresholds for pollutants is not enough. The MariaBox detection capacity has to be under the legal threshold, so as to enable early warnings and the possibility to prevent the pollution with adequate countermeasures. The first MariaBox prototype has been recently produced and is currently being tested and validated in the lab. Within 2017, the device will be replicated and 4 replicas will be installed in the 4 selected pilot locations.