Evaluation of the Removal of Selected Phthalic Acid Esters (PAEs) in Municipal Wastewater Treatment Plants Supported by Constructed Wetlands

Phthalic acid esters (PAEs) have a negative impact on living organisms in the environment, therefore, are among the group of Endocrine Disrupting Compounds (ECDs). Unfortunately, conventional methods used in municipal wastewater treatment plants (MWWTPs) are not designed to eliminate PAEs. For this reason, the development of cheap and simple but very effective techniques for the removal of such residues from wastewater is crucial. The main aim of this study was the evaluation of the removal of six selected PAEs: diethyl phthalate (DEP), di-n-octyl phthalate (DOP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP) and dimethyl phthalate (DMP), in real MWWTPs supported by constructed wetlands (MWWTP–CW system). For the first time, the possibility of using three new plants for this purpose, Cyperus papyrus (papyrus), Lysimachia nemorum (yellow pimpernel) and Euonymus europaeus (European spindle), has been presented. For determining the target PAEs in wastewater samples, a method of SPE (Solid-Phase Extraction)–GC–MS(SIM) was developed and validated, and for plant materials, a method of UAE (Ultrasound-Assisted Extraction)–SPE–GC–MS(SIM) was proposed. The obtained data showed that the application of the MWWTP–CW system allows a significant increase in the removal of DEP, DBP, BBP and DEHP from the wastewater stream. Euonymus europaeus was the most effective among the tested plant species for the uptake of analytes (8938 ng × g−1 dry weight), thus, this plant was found to be optimal for supporting conventional MWWTPs.

Degradation of dibutyl phthalate by Paenarthrobacter sp. Shss isolated from Saravan landfill, Hyrcanian Forests, Iran

Phthalic acid esters are predominantly used as plasticizers and are industrially produced on the million ton scale per year. They exhibit endocrine-disrupting, carcinogenic, teratogenic, and mutagenic effects on wildlife and humans. For this reason, biodegradation, the major process of phthalic acid ester elimination from the environment, is of global importance. Here, we studied bacterial phthalic acid ester degradation at Saravan landfill in Hyrcanian Forests, Iran, an active disposal site with 800 tons of solid waste input per day. A di-n-butyl phthalate degrading enrichment culture was established from which Paenarthrobacter sp. strain Shss was isolated. This strain efficiently degraded 1 g L–1 di-n-butyl phthalate within 15 h with a doubling time of 5 h. In addition, dimethyl phthalate, diethyl phthalate, mono butyl phthalate, and phthalic acid where degraded to CO2, whereas diethyl hexyl phthalate did not serve as a substrate. During the biodegradation of di-n-butyl phthalate, mono-n-butyl phthalate was identified in culture supernatants by ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry. In vitro assays identified two cellular esterase activities that converted di-n-butyl phthalate to mono-n-butyl phthalate, and the latter to phthalic acid, respectively. Our findings identified Paenarthrobacter sp. Shss amongst the most efficient phthalic acid esters degrading bacteria known, that possibly plays an important role in di-n-butyl phthalate elimination at a highly phthalic acid esters contaminated landfill.

Fast and Reliable Determination of Phthalic Acid Esters in the Blood of Marine Turtles by Means of Solid Phase Extraction Coupled with Gas Chromatography-Ion Trap/Mass Spectrometry

The presence of phthalic acid esters (PAEs) in marine environments is an important issue. These chemicals are able to affect marine organisms, particularly marine turtles, and to act as endocrine disrupters. In this paper, for the first time, a simple and reproducible analytical method based on solid-phase extraction (SPE) coupled with gas chromatography—ion trap/mass spectrometry (GC-IT/MS) was developed for the extraction of phthalates from the blood of marine turtles. The extraction was obtained by using C18 phthalates-free as the stationary phase. In order to individuate the best working conditions for the extraction, the adsorption isotherms and breakthrough curves were studied. The overall analytical methodology was validated in terms of limit of detection (LOD, 0.08–0.6 ng mL−1), limit of quantification (LOQ, 0.4–0.8 ng mL−1), and correlation coefficients (>0.9933). By using this procedure, percentage recoveries ranging from 89 to 103% were achieved. The precision parameters (intra-day and inter-day) were studied, and the obtained values were smaller than 12.5%. These data confirm the goodness of the proposed analytical methodology, which is applied to real samples.