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DCU Masters student, Martin Nolan, submits his MSc Thesis based on MONITOOL acquired knowledge

Martin Nolan (Dublin City University, DCU) presented in May his MSc Thesis under the Title "Evaluation of Diffusive Gradients in Thin Films for Trace Metal Monitoring of Coastal and Transitional Waterways", supervised by Dr. Blánaid White and Prof. Fiona Regan, based on works carried out during MONITOOL Project.

This work contains chapters rooted in different phases of MONITOOL Project, as monitoring methods, biofouling studies or voltammetry analysis of the samples. Specifically, the following chapters:

- A review of trace metal monitoring methods including biomonitoring and passive sampling methods and a summary of studies performed linking DGT performance to biomonitor organisms (Title: "Monitoring Trace Metals as Contaminants of Emerging Concern: Towards the Use of Passive Sampling Devices").

- The biofouling study, examining the extent of fouling at the studied sites, the speciation of the organisms, and some correlation studies with other water parameters, such as temperature and trace metals (Title: "Impact of Biofouling on Passive Sampling Devices and Examination of Fouling Environments of Atlantic and Mediterranean Waterways").

- Voltammetry chapter documenting the use of the ASV and cathodic CSV methods for the analysis of trace Ni, Cd and Pb (Title: "Stripping Voltammetry for Trace Analysis of Priority Metals in Coastal and Transitional Waters").

This is the first MSc Thesis that comes from MONITOOL. Martin Nolan has been involved in the project from its beginning, participating with DCU (project leader institution) in all the steps of the investigation.

Evaluation of the impact of biofouling on deployments of DGT

Deployments of Diffusive Gradients in Thin Film (DGT) devices in environmental waters can be made challenging due to the impact of biofouling. Biofouling is the attachment and growth of undesirable organisms on a surface and can impact the effectiveness of the DGT device. When microbial species such as bacteria and diatoms grow on the surface, they produce a sugar- and protein- rich substance known as extracellular polymeric substances (EPS). EPS spreads across a surface, forming a biofilm and allowing new organisms to attach more easily, including large organisms such as mussels, barnacles, and seaweed. A developed biofilm can affect DGT measurements by blocking the pores of the device, by binding metals, and introducing a new layer on top of the device, changing how metals move through the device.

There are a number of methods to help control the initial buildup of biofouling on a surface. Surfaces that will be exposed to environmental water for a long time, such as the hulls of ships or the casing of sensors, are often painted with biocidal paints, rich in copper or zinc. Alternatively, modified surface coatings can be used to prevent initial settlement or allow for easier removal of developed biofilms. Some sensors use chlorine jets or brushes to clean themselves allowing for longer deployments. However, these methods cannot be easily applied to DGT, as the results would be affected by metallic paints, chemically active surfaces, or changes to the boundary between the water and the device surface. For DGT, controlling the time the devices are deployed is currently the best solution to the biofouling challenge. Under the MONITOOL Project, DGT devices are deployed for 5 days, but evaluation of the impact of biofouling, and the organisms that cause it, is critical. Because MONITOOL covers such a large geographical region, it was expected that the biofouling would vary between hot and cold climates and during different seasons, both in the extent of fouling and the diversity of fouling organisms.

DGT devices were recovered for biofouling analysis from 31 sites during the cooler wet sampling period and the warmer dry sampling period. In addition, during the dry sampling period, Partners deployed panels designed by Dublin City University holding multiple surfaces to test biofouling for extended periods, including two types of membrane filters commonly used on DGT devices. Light microscopy was used to assess the percentage cover of the surfaces by fouling and Scanning Electron Microscopy (SEM) was used to identify the genera of diatoms and the types of other organisms causing fouling.

Many of the devices deployed for 5 days in MONITOOL experienced minimal impact by biofouling, with about half of the deployed devices having less than 1% surface coverage by fouling. This suggests our deployment period is generally suitable for use across various regions. The most heavily fouled device after 5 days was found during the dry season, with approximately 55% surface coverage. A DGT deployed at a nearby site was only about 9% covered, which demonstrates how unpredictable biofouling may be even at closely related sites. However, the longer deployment of the panels led to more than 99% coverage of the surface after 14 days at one site, pictured below.

Biofouling DCU

SEM imaging of the surface of a DGT membrane deployed for 14 days.

Across the 31 studied sites, there were 28 individual genera of diatoms identified on the standard DGT membrane composition (polyethersulphone). Some of these genera appeared at most sites studied, such as "Amphora", "Navicula" and "Cocconeis", which are among the most common marine diatoms. Some regions had diatoms which were unseen in other locations, and sometimes genera such as "Achnanthes" were almost exclusively present, as seen above. Work is continuing on the second surface type, the polycarbonate membranes, deployed alongside the polyethersulphone to better understand the diversity of fouling across the MONITOOL Project regions.

COVID-19 impact on MONITOOL project implementation

As everybody knows, the spread of the infection by the COVID-19 has been severely affected our lives and, in consequence, also to our planned activities on MONITOOL project.

All partner's institutions are closed and staff are working at home, except for very few people who carry out the critical authorized work.

In this sense, it's time to well organize all the pending MONITOOL works.

For example, a last experiment posed by IFREMER in order to determine metals on seawater samples taken from certain MONITOOL sites, in parallel with the DGT exposition and the filtered seawater analysis (ICP-MS and Voltammetry) under "stable" conditions, was planned for April 2020, as complementary field data to give consistency to DGT EQS determination. This task will be carried out now in the second half of 2020.

On the other hand, the MONITOOL Final Conference, which should have been held in Lisbon on May 2020, must be imperatively postponed. The new date is still pending, but it is most likely to take place in September this year. This event will be timed to coincide with the last Partner´s meeting.

Finally, this period of time will be used by partners to continue working on the processing of the data and publishing the main findings of the MONITOOL project in the more suitable science and technology journals. It is intended that, at least, four papers are ready to be published at project completion.

MONITOOL partnership wants to thank Interreg Atlantic Area program for the automatic extension on the project for 6 months due to the current COVID-19 pandemic situation.

Coronavirus

MONITOOL Partners take part in the annual ICES expert’s meetings

ICES ExpertsEvery year the International Council for the Exploration of the Sea (ICES) organises the meeting of experts from the North Sea and Atlantic regions to debate the most important and novel issues on the different fields of the Marine Environmental Sciences.

For several years, some members of MONITOOL project have attended the ICES working group of experts on marine chemistry and on marine sediments in relation to pollution. MONITOOL was presented for the first time to the ICES working group of marine sediments in March 2018. At that time, the meeting was organised in the Spanish Institute of Oceanography, in Murcia (Spain).

A year after, in March 2019, the progress achieved in the MONITOOL project was presented in the ICES expert´s working groups of marine sediments and marine chemistry that took place at the University of Evora (Portugal). On this occasion, the project´s promotional video was also shown.

This year´s meeting has been hosted by Miguel Caetano from IPMA (Instituto Português do Mar e da Atmosfera) between March 3 and 6 in Lisbon, where Maria J. Belzunce (AZTI-Tecnalia), has had the opportunity to present the project´s first results to the audience, followed by a discussion on the usefulness of the passive samplers for marine contamination evaluation, as well as on the necessity to develop assessment criteria for the passive sampling techniques.  

ICES meetings are attended by expert researchers from government agencies, universities and research institutes, being a key forum for the exchange of view and knowledge and networking.

Technical conference on passive samplers and MONITOOL project takes place in the Basque Country

Evento AZTI 3Under the framework of MONITOL project, the last 12th  March AZTI hosted a technical conference on passive samplers with the aim of presenting the MONITOOL project and the use of the most commonly used passive sampling techniques to evaluate the contamination of the environment.

Dr. Jean-Luis Gonzalez (IFREMER), Dr Iratxe Menchaca and Dr María Jesús Belzunce from AZTI explained to the attendees the main lines of the project and recent results, the advantages of passive sampling methods and how passive samplers have been used in MONITOOL campaigns as well as in other previous case studies. Dr Natalia Montero from the University of Cagliari presented a case study on the use of passive samplers to evaluate the impact of human activities in harbours.

Among other passive samplers, the Diffusive Gradient in Thin Films (DGT) were presented in depth to the participants as it is the passive sampling device used in MONITOOL. Among other issues, the advantages that they could have over other current methods to control heavy metal levels for coastal and transitional waters in the compliance of the Water Framework Directive were discussed.

The Conference took place in one of the headquarters of AZTI Foundation, located in Pasaia harbour, in the Basque Country.  It was attended, among others, by representatives of government agencies, universities, environmental consultants, research centres, students, port authorities and laboratories.