Does galvanic cathodic protection by aluminum anodes impact marine organisms?

Abstract

Background Cathodic protection by sacrificial anodes composed of aluminum-zinc-indium alloys is often applied to protect offshore support structures of wind turbines from corrosion. Given the considerable growth of renewable energies and thus offshore wind farms in Germany over the last decade, increasing levels of aluminum, indium and zinc are released to the marine environment. Although these metals are ecotoxicologically well-studied, data regarding their impact on marine organisms, especially sediment-dwelling species, as well as possible ecotoxicological effects of galvanic anodes are scarce. To investigate possible ecotoxicological effects to the marine environment, the diatom Phaedactylum tricornutum, the bacterium Aliivibrio fischeri and the amphipod Corophium volutator were exposed to dissolved galvanic anodes and solutions of aluminum and zinc, respectively, in standardized laboratory tests using natural seawater. In addition to acute toxicological effects, the uptake of these elements by C. volutator was investigated. Results The investigated anode material caused no acute toxicity to the tested bacteria and only weak but significant effects on algal growth. In case of the amphipods, the single elements Al and Zn showed significant effects only at the highest tested concentrations. Moreover, an accumulation of Al and In was observed in the crustacea species. Conclusions Overall, the findings of this study indicated no direct environmental impact on the tested marine organisms by the use of galvanic anodes for cathodic protection. However, the accumulation of metals in, e.g., crustaceans might enhance their trophic transfer within the marine food web.

Mass Cultivation of Microalgae: I. Experiences with Vertical Column Airlift Photobioreactors, Diatoms and CO2 Sequestration

“…The fact that production related poorly to total light may also be partly due to the fact that large and small cells acted differently with respect to light utilization (Table 6). Another hypothesis that will be tested is if zinc or aluminum anode materials in the reactor may have had deleterious effects on the cultivated diatoms [116]. This is an important issue to consider if underwater lights shall be applied since (nearly) all materials submerged in seawater are prone to corrosion.…”

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Study on Corrosion Resistance and Hydrogen Permeation Behavior in Inter-Critically Reheated Coarse-Grained Heat-Affected Zone of X80 Pipeline Steel

“…In addition, the fraction, size and distribution of M/A constituents can affect the electrical resistance, and then further affect the corrosion resistance [16]. Nowadays, the cathodic protection, which can suppress anodic reactions, is widely used for marine metals in engineering [17]. However, the cathodic reactions are enhanced on the steel surface, resulting in the adsorbing, absorbing and diffusion of hydrogen atoms [18].…”