Phthalate esters in baltic lagoons: Spatial distribution, ecological risks, and novel insights into their fate using...

Area of Science:

• Environmental Chemistry
• Environmental Microbiology
• Ecotoxicology

Background:

• Phthalate esters (PAEs) are prevalent organic pollutants with significant environmental concerns due to their widespread use and potential adverse effects.
• Lagoon ecosystems, characterized by semi-enclosed nature and high organic loads, are particularly susceptible to PAE pollution.
• Understanding PAE distribution and fate is crucial for assessing ecological risks in vulnerable coastal environments.

Purpose of the Study:

• To investigate the distribution of seven common PAEs in the water column and sediments of three European lagoons in the southern Baltic Sea.
• To identify the most concerning PAE congeners and assess their potential ecological risks to aquatic organisms.
• To reveal the microbial communities involved in PAE degradation and elucidate transformation pathways in these estuarine ecosystems.

Main Methods:

• Water and sediment sampling from Curonian, Vistula, and Szczecin lagoons.
• Quantification of seven common PAEs using analytical chemistry techniques.
• Shotgun transcriptomic analysis of microbial communities in field samples.

Main Results:

• Total PAE concentrations in water ranged from 0.03 to 1.45 μg L⁻¹, and in sediment from 0.008 to 1.06 μg g⁻¹, comparable to other European coastal areas.
• Di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DOP), and dimethyl phthalate (DMP) were identified as the most prevalent and concerning PAEs, posing a moderate risk.
• Active microbial communities, primarily Gram-negative bacteria in sediments, were found to degrade PAEs, with phthalic acid degradation not being a rate-limiting step.

Conclusions:

• PAE distribution patterns exhibit similarities in sediments but variations in the water column across the studied lagoons.
• Specific PAE congeners (DEHP, DOP, DMP) present a moderate ecological risk to aquatic life in these Baltic lagoons.
• This study provides the first evidence of active PAE degradation by microbial communities in Baltic lagoons, highlighting the role of sediment-associated Gram-negative bacteria.