Campaign For A Living Venice

Analyses conducted by the University of Padua and Ca’ Foscari on mollusks reveal that there are poisons in quantities 120 times higher than in the rest of the lagoon on the bottom of the canal that will be excavated to allow cruise ship to enter. And any excavation method will release them into the waters around the city

By Ugo Dinello

08 November 2023

Pb, Cvm, Pcdd and PCb. They sound like the names of political parties but are much more lethal: they are the chemical names of lead (Pb), dioxins (Pcdd), vinyl chloride monomer (CVM) and polychrome biphenyls (Pcbs). In practice, they are the fingerprints left at the crime scene that tell the story of Veneto’s industrial development.

The Poisoned Footprints

The footprints are clearly visible in an area in the center of the drainage basin of the Venetian lagoon, that is, that area between the waterways that originally ended up in the Serenissima lagoon before the Republic diverted them.

In this area of 2621 square kilometers which extends across the provinces of Padua, Vicenza, Treviso and Venice, 3,112 sites have been identified as being potentially polluted with residues from the most impactful industrial concentration in the Northeast: Porto Marghera. And it is precisely in front of the chemical plants, in the calm lagoon waters, that the footprints give way to the scene of the crime.

Conceived and planned in 1917 to respond to an emergency (the First World War), immediately after the end of the conflict Porto Marghera emerged as a chemical center of the Po Valley agricultural economy, developing thanks to the nitrogen cycle and the fertilizers derived from it.

Then it literally increased tenfold in the 1950s with the advent of the chemical industry for heavy metals linked to power plants, fuels and resins.

This was a period in which, even in the land registries, the canals of Marghera were defined as “drains” that were used as landfills by industries. Even waterways that flowed into the lagoon such as the Naviglio Brenta served this purpose: the enormous Mira Lanza had two “intakes” to pump water from the Naviglio Brenta for use in cleaning the industrial sludge tanks, and then reintroduced the residual wastewater into the same canal. All industrial waste therefore ended up in the lagoon and the sea.

From 1950 onwards, chlorine chemistry developed. Polychlorinated dibenzodioxins, vinyl chloride monomer (CVM) and polychlorinated biphenyls (PCBs) were suddenly added to the lead and acids and petroleum derivatives that were already being discharged into the drains of Porto Marghera; i.e. highly carcinogenic chemical compounds that remain in the environment with great persistence, so much so that they are defined as “eternal pollutants”.

When the first national water protection laws appeared at the end of the 1960s, the big business of soil and groundwater pollution began, with the feverish search for quarries and places to dig to bury the sludge drums with toxic waste.

However, the pollution in the lagoon did not stop here. The constant need for spaces to be industrialized and for excavating canals led to the creation of reclaimed areas in the lagoon: actual islands made of the mud from the excavations of the Canale dei Petroli (between Alberoni and Porto Marghera), which took place between 1962 and 1968, and from the industrial excavations of Porto Marghera itself. These islands then released part of their poisons into the water.

In fact, one thing that has come to be understood over time is that the excavation of canals is the worst thing that can be done in the lagoon if it is not managed correctly.

The 2023 Sludge Protocol

The quantity of pollutants released by excavation of the lagoon bed, in the form of heavy metals and polychlorinated biphenyls, is in fact capable of significantly modifying the quality of living organisms.

But to understand the impact of these activities it was necessary to arrive at a measurement: to investigate the possible effects of complex mixtures of chemical contaminants present in lagoon sediments on animal species residing in the lagoons and coastal areas.

This subject, which combined the chemical characterization of the sediments with the evaluation of the ecotoxicological effects on animal species, is of extreme interest in the lagoon from Venice, in particular following the recent approval of the so-called “new sludge protocol” (Decree 22 May 2023 n.86).

In fact, soon it will be necessary to excavate 1,280,000 cubic meters of sediment to bring the “grandi navi” back to Venice. In order to get the cruise ships back into the lagoon and increase the number of tourists in the historic center, it will be necessary to bring them in from the Alberoni, pass through the Petroli canal and then take them to Marittima station via the old Vittorio Emanuele III canal.

The Channel to be Doubled

For this reason, the canal, which is currently 7.5 meters deep and 50 meters wide, will be dug to reach 9 meters deep (officially, but it is feared that it will reach 11) and 80 meters wide (officially) but here too there are fears that at least 100 meters of width is needed for the maneuvering of large ships (whose length is almost 300 meters).

What will be found in the Vittorio Emanuele mud? Nobody knows this, even if in the “Tender for the design and execution of the works for the dredging of the access channel to the maritime station” published by the structure of the Special Commissioner for cruise ships, Fulvio Lino di Blasio, who is also president of the Port Authority, it is expected that depending on the level of pollution, the excavated sludge will be redistributed in the lagoon or deposited on the sludge transfer island in front of Fusina (Isola delle Tresse) that the Port wants to use. The dredging must be completed by 2026 because the ships are planned to return to Marittima station in Venice by 2027. So, time is very tight.

The Effects on Living Beings. The Study

So, what will the effects of the poisons that we risk redistributing in the lagoon with the excavation of polluting sludge be on living beings?

The first answer comes from a study published by the Department of Comparative Biomedicine and Nutrition and the Department of Biology of the University of Padua, in collaboration with Ca’ Foscari University of Venice, in the journal “BMC Biology”.

This study cataloged the effects of exposure to sediments sampled in different sites on the bottom of the Vittorio Emanuele III canal (the canal that connects Marghera to the city of Venice) on the Philippine clam, the Ruditapes philippinarum, i.e. the clam that arrived in the lagoon from east and which has taken the place of the original “caparossolo”, i.e. venerupis decussata, which is increasingly disappearing.

Thanks to this study, which is part of the CORILA Venezia 2021 project financed by the MIT – Public Works Authority of the Triveneto, it was possible to define the molecular mechanisms underlying the toxicity of contaminated sediments.

“Caparossola” were taken in normal areas of the lagoon (control specimens) and compared to the specimens found on the bottom of the Vittorio Emanuele canal.

“Organisms exposed to sediments, whose concentrations of pollutants such as PCBs had values up to 120 times higher than in control areas, underwent a significant alteration in the expression of genes involved in the response to complex chemical mixtures characteristic of urban and industrial areas – explains Prof Tomaso Patarnello, senior author of the research – In particular, the alteration concerned the expression of the genes that are part of the mTORC1 metabolic pathway, central in the coordination of the cellular response to chemical stress.”

But that is not all. “The immune response is also significantly increased – explains Patarnello – following the modification of the composition of the clam’s microbiome with the significant increase in microorganisms potentially pathogenic for the animal.”

“Overall, the results obtained highlight how the correct management of dredged sediments is essential for the conservation of this species and, more generally, how investigations conducted at a molecular level can also contribute to understanding the complexity of the potential adverse effects on organisms of the lagoon of Venice due to exposure to contaminated sediments,” says prof. Massimo Milan, a corresponding author.

According to the University of Padua, the research highlights how the correct management of dredged sediments is essential not only to avoid the spread of poisons in the lagoon but also for the conservation of the species that live there.

The Scheduled Excavation and its Effects

But at the moment no one is able to prevent the excavation of the canal from releasing a considerable amount of pollutants around the lagoon, in part because the same “Dredging Notice” published by Commissioner Di Blasio expressly talks about redistribution of sludge in the lagoon or transfer to an island, but always keeping it in the lagoon.

A person who knows the subject very well is Stefano Raccanelli, a renowned environmental chemist, whose research triggered the investigation into the Ilva of Taranto and who acted as a consultant during the Porto Marghera petrochemical trial.

Raccanelli has been addressing this topic for some time: his 1987 doctoral thesis in chemistry was research entitled “The resuspension of sediments as a cause of PCB pollution in the Venice Lagoon”.

He also has remarkable experience with regards to the study of organisms faced with pollution: during the Petrochemical trial in 1998 his studies demonstrated that lagoon gastropods such as garusoli were so polluted that they actually changed sex.

“The hypothesis that highly polluted sediments, if excavated with traditional methods, will form a resuspension that will flow around the lagoon, spreading pollutants, is an effect that has a very high probability of occurring. I would say that based on all known studies it’s something obvious,” explains Racccanelli.

It would be even worse if this sludge is “redistributed” in the lagoon itself, causing its poisons to pollute other living organisms.

Practical Solutions

Is there a practical solution? “Yes, they exist, and we can even choose between two. The first is not to dig the canals with the systems known and used so far in the lagoon. In fact, to this day the seabed is excavated with a bucket that removes and lifts the mud, dispersing it.”

In this case, explains Raccanelli, the dispersion of all the poisons accumulated on the seabed will be automatic.

“The other system – he continues – is to use a water pump that sucks up the sludge and centrifuges it, separating the water from the centrifuged product. This solution would have less impact than the excavation always used until now, but it has never been used in these areas. We can therefore imagine, after the excavation of the Canale dei Petroli, the quantity of poisons that would be dispersed in the lagoon.”

It goes without saying that if the centrifuged sludge were then “redistributed” in the lagoon, in whatever form, the effects would be deleterious and the redistribution in the waters would be automatic. There are also many reservations about depositing the sludge on an island within the lagoon boundary, which by definition is subject to tides and water infiltration.

The centrifuged product must therefore be taken out of the lagoon area to an appropriately equipped landfill which, however, given the enormity of the number of cubic meters to be excavated, does not exist.

Therefore, the excavation of Vittorio Emanuele III will Inevitably see the highly polluted mud, with a concentration of poisons 120 times higher than normal, redistributed in the lagoon or taken to a lagoon island.

However, Raccanelli notes that even in this case there is still a second solution: “It is not to dig the canal, preventing another enormous quantity of poisons from dispersing into the waters of Venice”.

This is something that the Serenissima also did in the past, carefully avoiding digging too many canals near the Murano glass factories, which used already known poisons such as arsenic and lead.

However, this solution would clash with the will of the current administrative class, which has never made a secret of its desire to bring cruise ships back to the historic center.

However, Raccanelli offers another important reason to consider not intervening on the canal: “We must, in fact, also remember that if the Vittorio Emanuele Canal is excavated it will cause another enormous damage, because it will form a gigantic vortex a few meters from Venice which will attract high waters in the event that MoSE is overpassed”.

-Source: La Nuova di Venezia e Mestre