Photodegradation is the chemical conversion of large, toxic, and complex molecules into non-toxic, simpler, and lower molecular weight species due to light exposure. Heterogeneous photocatalysis has sufficient potential to degrade toxic organic pollutants present in wastewater. As industries discharge their effluents containing organic pollutants into natural water bodies, which penetrate into the subsurface through connected pores it is necessary to study this process in natural or tap water. Tap water (TW) is mainly obtained from underground wells having inorganic salts in a minute quantity with a conductivity of 500 μS/cm. TW contains inorganic anions, which affect the photocatalytic activity and photocatalysis process. The aim of this review is to evaluate the effect of TW on the photo-degradation of organic pollutants such as dyes, pharmaceutical products, pesticides, etc., with the support of the literature. The TW had a diverse effect on the photodegradation of organic pollutants; either it may enhance or decrease the rate of pollutants’ photodegradation.

The Messinian Salinity Crisis (MSC; 5.97–5.33 Ma) is an enigmatic episode of paleoceanographic change, when kilometer‐thick evaporite units were deposited in the Mediterranean basin. Here we use geochemical (biomarker and isotope) data to reconstruct sea surface temperature, salinity, and productivity‐preservation changes in the Mediterranean basin just before the MSC. The proxy data indicate that the Mediterranean Sea was significantly saltier and colder between 6.415 and 6.151 Ma, than between 6.151 and 5.971 Ma. Salinity decrease at 6.151 Ma seems to be a relatively fast event just preceding the inception of a warming phase that lasted almost uninterrupted until the MSC onset. The water exchange with the Paratethys could have caused, along with the African rivers, an increased freshwater supply, resulting in normal marine Mediterranean waters between 6.151 and 5.971 Ma, despite the severe restriction of marine connections with the Atlantic at that time. Sea surface temperature changes determined a sharp drop in productivity and/or preservation of organic matter, marked by deposition of calcareous marls. Productivity and preservation were relatively high and constant until 6.01 Ma. Afterward, increased influx of terrestrial organic matter and probably enhanced water column stratification prevailed. Around 5.971 Ma, modifications in aquatic versus terrestrially derived biomarkers indicate changes in organic matter influx at the MSC onset.

This integrated study (field observations, micropalaeontology, magnetostratigraphy, geochemistry, borehole data and seismic profiles) of the Messinian–Zanclean deposits on Zakynthos Island (Ionian Sea) focuses on the sedimentary succession recording the pre‐evaporitic phase of the Messinian salinity crisis (MSC) through the re‐establishment of the marine conditions in a transitional area between the eastern and the western Mediterranean. Two intervals are distinguished through the palaeoenvironmental reconstruction of the pre‐evaporitic Messinian in Kalamaki: (a) 6.45–6.122 Ma and (b) 6.122–5.97 Ma. Both the planktonic foraminifer and the fish assemblages indicate a cooling phase punctuated by hypersalinity episodes at around 6.05 Ma. Two evaporite units are recognized and associated with the tectonic evolution of the Kalamaki–Argassi area. The Primary Lower Gypsum (PLG) unit was deposited during the firstMSCstage (5.971–5.60 Ma) in late‐Messinian marginal basins within the pre‐Apulian foreland basin and in the wedge‐top (<300 m) developed over the Ionian zone. During the secondMSCstage (5.60–5.55 Ma), thePLGevaporites were deeply eroded in the forebulge–backbulge and the wedge‐top areas, and supplied the foreland basin's depocentre with gypsum turbidites assigned to the Resedimented Lower Gypsum (RLG) unit. In this study, we propose a simple model for the Neogene–Pliocene continental foreland‐directed migration of the Hellenide thrusting, which explains the palaeogeography of the Zakynthos basin. The diapiric movements of the Ionian Triassic evaporites regulated the configuration and the overall subsidence of the foreland basin and, therefore, theMSCexpression in this area.

Massive salt accumulations, or salt giants, have formed in highly restricted marine basins throughout geological history, but their impact on biodiversity has been only patchily studied. The salt giant in the Mediterranean Sea formed as a result of the restriction of its gateway to the Atlantic during the Messinian Salinity Crisis (MSC) 5.97 to 5.33 million years ago. Here, we quantify the biodiversity changes associated with the MSC based on a compilation of the Mediterranean fossil record. We conclude that 86 endemic species of the 2006 pre-MSC marine species survived the crisis, and that the present eastward-decreasing richness gradient in the Mediterranean was established after the MSC.