ORCID Profile
0000-0001-8811-7163
Current Organisations
University of Newcastle Australia
,
University of Colombo
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Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.JHAZMAT.2022.129667
Abstract: Perfluorohexanesulfonic acid (PFHxS) is one of the persistent organic pollutants that has been recommended to be listed in Annex A of the Stockholm Convention. It has gained increasing attention in recent years due to its toxic effects. The guideline values of PFHxS are commonly associated with PFOS in various countries and regulatory agencies. In this study, multispecies bioassays were conducted to determine the ecological toxic effects of PFHxS, including plants, soil invertebrates, and soil microorganisms, which indicated the EC10/NOEC values ranged from 2.9 to 250 mg/kg. Where possible, logistic models were used to calculate the EC30 values for various endpoints. The species sensitivity distributions were employed to estimate the ecological investigation levels for PFHxS contamination in soils using toxicity results from literature and this study. The calculation using EC10/NOEC values from both literature and this study indicated a most conservative HC5 as 1.0 mg/kg (hazardous concentration for 5 % of the species being impacted). However, utilisation of EC30 values derived from this study resulted in a much higher HC5 for PFHxS in contaminated soils (13.0 mg/kg) which is at the higher end of the existing guideline values for PFOS for protecting ecological systems. The results obtained in this study can be useful in risk assessment processes to minimize any uncertainty using combined values with PFOS.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 11-2023
Publisher: Elsevier BV
Date: 2023
Publisher: Wiley
Date: 02-05-2018
DOI: 10.1111/ANDR.12499
Abstract: Parabens are used as antimicrobial preservative agent in many commercial products including cosmetics and pharmaceuticals. Weak oestrogenic and antiandrogenic activities have been attributed to parabens in in vitro and in vivo studies. In this study, human spermatozoa were exposed to different concentrations of an equimolar paraben mixture containing methyl, ethyl, propyl and butylparaben as well as to methylparaben alone at a concentration that is typical of commercially available vaginal lubricants. The induction of oxidative stress and DNA damage was then assessed at different time points. Our results demonstrate that the paraben mixture was capable of stimulating the generation of mitochondrial and cytosolic reactive oxygen species (ROS), inhibiting sperm motility and viability in a dose-dependent manner. The ability of in idual parabens to activate ROS generation and induce oxidative DNA damage was related to alkyl chain length. At the concentration used clinically, methylparaben inhibited sperm motility after both 2 and 5 h exposure (p < 0.05) and affected cell viability (p < 0.01) while augmenting ROS production and oxidative DNA damage. However, DNA fragmentation was not evident following methylparaben exposure. Based on these results, we conclude that, at the concentrations used in commercially available formulations, parabens may impair sperm motility, enhance the generation of mitochondrial ROS and stimulate the formation of oxidative DNA adducts. Taken together, these data underline the potential cytotoxic and genotoxic impact of such compounds in a clinical setting.
Publisher: Frontiers Media SA
Date: 23-12-2020
Abstract: Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are persistent organic contaminants of concern to human and environmental health. Several literature reviews and laboratory column experiments have been conducted to determine the transport parameters and to describe the fate of PFAS as they migrate in subsurface environments. However, there are very few case studies focusing on contaminated sites with high-resolution field data. Such studies are crucial for the validation of transport simulation models that have been developed from experimental studies, prior to their broader applications. The key purpose of this research was to evaluate lithological separations of PFAS fractions as they are transported in the vadose zone of a historically (1979) contaminated site where Aqueous Film Forming Foam (AFFF) formulations (3M Lightwater™ and Ansulite™) have been used for fire training exercises. Surface and subsurface soils, and groundwater s les were collected across the site and a total of 29 PFAS compounds were selected as target analytes. The results indicated a distinct profile of PFAS concentration with depth at most of the test bores, exhibiting separation of PFAS as transported in vadose zone soils. Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonic acid (PFOS), and Perfluorohexane sulfonic acid (PFHxS) were the predominant compounds detected in the site s les and they have been found in near-surface soils (& m) with concentrations declining with depth. The concentration of the 6:2 fluorotelomer sulfonate showed little change with depth in most of the test bore wells. The percentage concentration of each compound relative to the sum of PFAS, and the ratio of PFHxS/PFOS with depth, suggested transformation processes. Despite the relatively high solubility of PFAS, and that the application of AFFF has been ceased for some years at the site, there were still significant concentrations of PFAS adsorbed to the vadose zone soils that acted as ongoing sources of contamination to groundwater.
Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 05-2023
No related grants have been discovered for Chamila Samarasinghe.