Glucocorticoids in Freshwaters: Degradation by Solar Light and Environmental Toxicity of the Photoproducts

Abstract

The photodegradation process of seven glucocorticoids (GCs), cortisone (CORT), hydrocortisone (HCORT), betamethasone (BETA), dexamethasone (DEXA), prednisone (PRED), prednisolone (PREDLO) and triamcinolone (TRIAM) was studied in tap and river water at a concentration close to the environmental ones. All drugs underwent sunlight degradation according to a pseudo-first-order decay. The kinetic constants ranged from 0.00082 min−1 for CORT to 0.024 min−1 for PRED and PREDLO. The photo-generated products were identified by high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The main steps of the degradation pathways were the oxidative cleavage of the chain 17 for CORT, HCORT and the rearrangement of the cyclohexadiene moiety for the other GCs. The acute and chronic toxicity of GCs and of their photoproducts was assessed by the V. fischeri and P.subcapitata inhibition assays. The bioassays revealed no significant differences in toxicity between the parent compounds and their photoproducts, but the two organisms showed different responses. All samples produced a moderate acute toxic effect on V. fisheri and no one in the chronic tests. On the contrary, evident hormesis or eutrophic effect was produced on the algae, especially for long-term contact.

Induced selectivity in the photochemistry of estrone derivatives in sustainable and micellar environment: preparative and mechanistic studies

“…The past decades have witnessed a rapid development of the photochemistry of steroids which is a challenging topic that produces continuous reports in both academic and industrial area. Indeed, recently reports on the photodegradation of some steroidal hormones in aquatic environments performing the irradiation under direct or photosensitized procedures have been studied [1][2][3][4][5]. For example, the photodegradation of 17β-estradiol (E2), an endocrine-disrupting hormone was investigated in wastewater effluents at different pH values under simulated solar irradiation employing effluent organic matters (EfOM) as triplet photosensitizers [1].…”

“…Furthermore, the photoinduced degradation of an estrogen derivative, such as 17α-ethinylestradiol (EE2) has been studied in detail in terms of kinetic and mechanistic viewpoints using aquatic humic acid and fulvic acid solutions simulating natural water matrixes [4]. The photodegradation by solar light of glucocorticoids in freshwater have been reported and it was found that the photoproducts are environmental toxic compounds as was assessed by V. fischeri and P. subcapitata inhibition assays [5]. The effect of solar UV light on anti-inflammatory corticosteroids dexamethasone, prednisone and prednisolone in water and in micellar solutions under different atmospheric conditions has been studied in terms of kinetic, mechanistic and toxicological aspects [6].…”

TiO2-Photocatalyzed Water Depollution, a Strong, yet Selective Depollution Method: New Evidence from the Solar Light Induced Degradation of Glucocorticoids in Freshwaters

“…Due to the above, new strategies to abate GCs and those emerging contaminants of the aquatic environment that affect endogenous steroid actions have to be taken into account. In a recent paper [23], we studied the possibility of addressing this issue through direct photolysis in natural water. However, GCs photoreactivity under environmental conditions was found to be almost negligible due to their rigid cyclopetaperhydropenathrene structure and their limited light absorption in such highly diluted solutions, also when a more absorbing moiety, such as cross-conjugated chromophore in ring A, was present in the structure (see Scheme 1, X = H, F, Y = OH, O).…”

Contaminants of emerging concern and aquatic organisms: the need to consider hormetic responses in effect evaluations

“…A further survey of the literature for the purpose of this study revealed ample evidence suggestive of hormesis for numerous aquatic organisms and various pollutants and emerging contaminants in dozens of publications, of which only a few selected examples are cited here (older examples can also be traced in the therein references). These examples include a plethora of species, such as of algae (microphytes) [38][39][40][41][42][43][44][45][46][47][48][49] , aquatic flowering plants [50] , organism-attached biofilms [51] , crustaceans [52][53][54][55][56][57] , cyanobacteria [49,[58][59][60][61] , fishes [62][63][64][65][66][67][68][69] , macrophytes [70][71][72][73][74][75] , marine polychaete [76] , mollusks (e.g., clams and mussels) [77,78] , periphyton [79] , phytoplankton [80] , sea anemones [81,82] , and snails [83] . Responses suggestive of hormesis were found for molecular (molecules...…”

“…Responses suggestive of hormesis were found for molecular (molecules involved in oxidative stress), cellular (e.g., growth and density), and whole-organism (e.g., growth and body mass) endpoints, as well as endpoints suggesting potential sub-NOAEL effects on organismic interactions, such as via altered feeding activity [83] . Such responses were induced by chemicals such as antibiotics/antifungals [38,39,42,45,50,51,67,70,71,75] , steroid hormones [41,83] , and other human drugs [63,69] , bisphenol A and its substitutes [66] , chemical leached from disposed light sticks [55] , electroplating processemitted particulate matter [40] , effluents from textile-dyeing wastewater treatment plants [46] , fullerene crystals (nC 60 ) [57] , metals and ionic liquids [62,77,81,82] , micro/nanoplastics and their leachates [43,44,47,53,60,64,80,84] , engineered nanomaterials [58,59,61,65] , pesticides [48,49,52,56,[72][73][74]79,84] , phthalic acid esters ...…”