IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

1W_4F-P1

Date/Time: July 21 Poster

Volcanic health hazard: the acidification of seawater and trace metals accumulation
study in Blue Mussels (Mytilus galloprovincialis). Vulcano Island (Italy)
Fulvio Boatta1 , Walter D’Alessandro2 , Antonina L Gagliano1 , Sergio Calabrese1 , Marcello Liotta3 ,Marco Milazzo1 , Francesco Parello1
1DISTEM University of Palermo, Italy, 2 INGV Palermo, Italy, 3 DISTABIF University of Napoli, Italy
E-mail: fulvioboatta@gmail.com

Mussels are considered to be heavy metals bio-accumulators and, at least in coastal areas, represent a significant
part of the humans diet. Due to the fact that such animals could be breeding in active volcanic areas interested byacidification of seawater and increased mobility of heavy metals, the consumption of mussels could represent ahazard for human health.
Acidification of seawater is due to the presence of submarine vents releasing abundant volcanic CO2-rich fluids. In
aquatic system gaseus CO2 dissolves and, hydrates to form weak carbonic acid, which is the main driver of natural
weathering reactions. The result of the CO2 increase is seawater acidification.
Vulcano Island, the southernmost of Aeolian Islands, is located in the Southern Tyrrhenian Sea (Italy),
approximately 18 miles off the NE coast of Sicily. Four geochemical surveys of the Levante Bay were carriedout in April - September 2011 and May - June 2012. The main physico-chemical parameters (T, pH, Eh, electric
conductivity) were measured at more than 70 sites and more than 40 samples for chemical analyses were collected
at representative points. Major and trace elements dissolved in water, the chemical composition of dissolved gases(He, H2, O2, N2, CH4 and CO2) and the isotopic composition of total dissolved inorganic carbon were determinedin the laboratory.
The bubbling CO2 produces a strong decrease in pH from the normal seawater value of 8.2 down to 5.5. In thearea close to the main degassing vents, characterized by very low pH, macroorganisms are absent. Further northin the bay, about 300 m from the main vents the pH of seawater is only slightly lower than normal ocean waters(pH 8.2 - 7.8) resembling conditions in equilibrium with the high atmospheric CO2 concentrations expected in thenear future up to the end of the century. Therefore environments like these, naturally enriched in CO2, are goodlaboratories to study the consequences of ocean acidification on aquatic biota. Furthermore acidification is tightly
linked with the mobility and bio-availability of heavy metals in sea water.
A Blue Mussels transplant experiment was done along the pH gradient in order to estimate the accumulation
capability in relationship with acidification of seawater. At the end of the experiment the mussels showed anincrease of concentration for some elements such as (Fe, As, Mo, V and Pb) with respect to blanks.
The present study provides important information about the best environmental management of active volcanic
areas such as Vulcano Island.

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