Uptake and photoinduced degradation of phthalic acid esters (PAEs) in Ulva lactuca highlight its potential application in environmental bioremediation

Abstract

The bioaccumulation of phthalates was studied in fragments of Ulva lactuca exposed for a maximum of 31 days at different concentrations of a solution of six phthalic acid esters (PAEs). The algal matrix showed rapid uptake since the first sampling, which increased over the time of the experimental period, at the end of which seaweed’s bioaccumulation potential was also evaluated. After the uptake, the algal matrix was subjected to UV irradiation in order to verify the removal of the phthalates. PAEs with higher octanol–water partition coefficients (logKow) and molecular weights were preferentially uptaken by U. lactuca in all the exposure experiments. It was observed that both accumulation (biota-sediment accumulation factor (log10BSAF) ranging from 3.75 to 4.02) and photodegradation (higher than 70% removal for all phthalates in 8 h) are more efficient at lower concentration levels. These results suggest the potential use of the algal matrices for environmental bioremediation, in order to mitigate the impact of pollution from ubiquitous pollutants such as PAEs.

The Origin of Phthalates in Algae: Biosynthesis and Environmental Bioaccumulation

“…Although some macroalgae, such as Ulva sp., Sargassum sp., Gracialaria sp., or Pterocladia sp., have the remarkable capacity to adsorb lipophilic pollutants [13,30] and endocrine active substances [15], including phthalates [8,48], and can potentially be used for bioremediation approaches, studies have shown that micro-and macroalgae produce phthalates via biosynthetic pathways [33,34,44] probably through the shikimic acid pathway [3,49].…”

“…Algae's biosorption capacity is affected by physicochemical factors, in particular pH, temperature, the type and log K ow of PAEs, weight of algal biomass, and PAEs' concentration [8,48,53].…”

“…Once algal biomass has absorbed phthalates, these pollutants can be removed from the organic matrix using green techniques, such as photoinduced degradation [8]. This matrix can be reused for the same bioremediation application [48], as well as for other applications, such as fertilizers in agriculture.…”

“…The large amount of plastic pollution has led to the significant accumulation of these substances in aquatic environments. Once PAEs are released, they can be transferred through the food chain, causing detrimental effects to the health of exposed organisms and ultimately impacting the ecosystem's functioning [4,8]. In fact, phthalates are known to be endocrine-active substances (EAS) and can cause different liver, reproductive, metabolic, and developmental diseases [4].…”

“…Among these metabolites, phthalates are a cause for concern due to their frequent use in algal matrices for various purposes that involve direct exposure. At the same time, algal species can act as bioremediators in environmental bioremediation by accumulating or degrading a wide range of pollutants [8,[13][14][15].…”