The impact of aluminium sacrificial anodes on the marine environment: A case study

Impact of Galvanic Anode Dissolution on Metal Trace Element Concentrations in Marine Waters

“…3). Total Al and Zn seawater concentrations reached values about 100 times and 10 times, respectively, higher than those measured in the RT or in harbor seawaters under cathodic protection by anodes (9 to 70 μg L -1 for Al and 25 to 45 μg L -1 for Zn, this study; Bird et al 1996;Gabelle et al 2012;Leleyter et al 2007). For comparison, total concentrations in open ocean are below 10 μg L -1 for Al and 0.5 μg L -1 for Zn (Alberti et al 2005;Brown et al 1989;Ohnemus and Lam 2015).…”

“…The chemical analysis on the settled tank sediments and its interstitial waters showed a huge enrichment in Al, Zn, and In at the end of the experiment compared to values measured in the reference sediment tank (Table 2). These values largely exceeded the measured concentrations in superficial marine sediments, even in those impacted by human activities: 10-33 mg g -1 for Al, 24-167 μg g -1 for Zn, and 2.9 10−3-5.7 ng g -1 for In (Boughriet et al 2007;Duan et al 2010;Gabelle et al 2012;Santos et al 2005;Tessier et al 2014). These results demonstrated that the cathodic protection by galvanic anodes could strongly impact metal concentrations in the solid fraction.…”

“…Consequently, at a real interface of harbor sediments, due to local hydrodynamics and sedimentation rate, the solid corrosion products formed during cathodic protection should induce only local (close to the anode) and temporary contamination after an erosion episode. Indeed, a previous study showed that anodic dissolution induced a significant metal enrichment of superficial sediments sampled only from undredged areas and were limited to the immediate vicinity (<20 m) of the Al anodes (Gabelle et al 2012).…”

“…Metals may be released as dissolved species or as particles of solid phase. Once released, these metals could diffuse and contaminate surrounding waters or may be accumulated in the suspended particle matter (SPM), sediments, and biota (Caplat et al 2010;Gabelle et al 2012;Leleyter et al 2007;Mao et al 2011;Mottin et al 2012;Rousseau et al 2009).…”

“…Consequently, metal inputs from anode dissolution could be significant in these environments, causing potential ecological damage (Jelmert et al 2000;Mao et al 2011). However, the fate of metals from anode dissolution in the marine environment is not well characterized and has been poorly studied (Bird et al 1996;Caplat et al 2010;Gabelle et al 2012;Leleyter et al 2007;Mao et al 2011;Mottin et al 2012;Rousseau et al 2009).…”