Table 9 Environmental impact and... | Emerald Publishing

Table 9

Environmental impact and associated concerns arising from the materials used in AM to build ARs

Main material used	Marine environmental impacts/concern	Reference
Polylactic acid (PLA)	PLA gradually disintegrates into microplastic in underwater conditions, inhibiting algae growth and reducing the survival of up to 40% of phytoplankton. While it has a minimal effect on molluscs, it can adversely affect fish behaviour through ingestion, resulting in negative impacts	Ali et al. (2023)
Cement Portland	Cement, composed of calcium carbonate, is conducive to the colonisation of benthic calcareous skeletons. However, a surface with high alkalinity (pH 12–13) might inhibit the settlement of species that are intolerant to such alkaline conditions	Natanzi et al. (2021)
Shell aggregate	Enhances the circular economy and reduce carbon dioxide emissions. The use of oyster shell waste increases surface porosity due to its material properties, thereby facilitating the initial biological attachment	Hou et al. (2016), Kong et al. (2022)
Fly ash	Its specific constituents like selenium in high concentrations has the potential to impact the early life stages of fish. Containing a range of metals and other elements, fly ash can become toxic to biological ecosystems at high concentrations	Greeley et al. (2012)
Terracotta clay and ceramics	Its composition featuring non-toxic oxides and a neutral pH, is ideal for marine environments applications, supporting biological productivity and ensuring no adverse effects	Kalam et al. (2018)

Main material used	Marine environmental impacts/concern	Reference
Polylactic acid (PLA)	PLA gradually disintegrates into microplastic in underwater conditions, inhibiting algae growth and reducing the survival of up to 40% of phytoplankton. While it has a minimal effect on molluscs, it can adversely affect fish behaviour through ingestion, resulting in negative impacts	Ali et al. (2023)
Cement Portland	Cement, composed of calcium carbonate, is conducive to the colonisation of benthic calcareous skeletons. However, a surface with high alkalinity (pH 12–13) might inhibit the settlement of species that are intolerant to such alkaline conditions	Natanzi et al. (2021)
Shell aggregate	Enhances the circular economy and reduce carbon dioxide emissions.The use of oyster shell waste increases surface porosity due to its material properties, thereby facilitating the initial biological attachment	Hou et al. (2016), Kong et al. (2022)
Fly ash	Its specific constituents like selenium in high concentrations has the potential to impact the early life stages of fish. Containing a range of metals and other elements, fly ash can become toxic to biological ecosystems at high concentrations	Greeley et al. (2012)
Terracotta clay and ceramics	Its composition featuring non-toxic oxides and a neutral pH, is ideal for marine environments applications, supporting biological productivity and ensuring no adverse effects	Kalam et al. (2018)

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