«New pollutants» in aquatic environment. Drugs, ultraviolet filters, artificial sugar substitute products (review)

Summary

The data on the concentrations of illegal drugs (cocaine and its metabolites, opioids, marihuana derivatives, amphetamine and ecstasy group compounds), ultraviolet filters found in sun protection creams (titanium dioxide, para-aminobenzoates, cinnamates, benzophenones, dibenzoylmethanes, camphor derivatives, benzimidazoles), and artificial sugar substitute products (sucralose, aspartame, saccharin, acesulfame) in waste, surface, ground and drinking water are presented. As a result of incomplete removal in the processes of physical, chemical and biological treatment at the traditional wastewater treatment facilities the given pollutants get into the natural aquatic environment where can be found in concentrations mainly of nanograms per liter of water. In foreign countries a marked increase of studies in the field of aquatic environment pollution with illegal drugs, UV filters and artificial sugar substitute products dates back to the beginning of the 2000-ies. Herewith the main attention is paid to improving the efficiency of degradation of these substances at the treatment facilities; to the transformation in aquatic environment resulted from the impact of the natural factors with possible formation of products more toxic than the original substances; to the potential role of these substances as precursors of water disinfection byproducts; to the mechanism of toxicological effect and related risks for aquatic organisms and human beings; to the development of analytical methods.

Key words

toxicological effect , drugs , ultraviolet filters , artificial sugar substitute products , aquatic environment , photodegradation

Pharmaceuticals in natural, drinking and wastewater
(review)

Summary

The presence of pharmaceuticals in the natural water environment is becoming a subject of focused attention. For the moment more than 180 pharmaceuticals (pain relievers and anti-inflammatory drugs, antibiotics, beta-blockers, contrast agents, Lipid-lowering agents, psychiatric medicines, hormones and antiseptics) and their metabolites that keep bioactivity have been registered in the water environment in many countries. Most often detected among them are diclofenac, carbamazepin, clofibric acid, ibuprofen, bizafibrate, sulfamethoxazole, trimethoprim, phenazone, ketoprofen, roxithromycin, triclozan, iopromide. The sources of pharmaceuticals ending up in municipal wastewater are residential sector, medical institutions, pharmaceutical factories, animal clinics and live stock breeding complexes. The concentration of separate pharmaceuticals can reach 40 µg/l. At the traditional wastewater treatment facilities pharmaceuticals can be removed in the process of biodegradation/biotransformation and activated sludge adsorption. However, the efficiency of removing many of them is typically low. The concentration of certain pharmaceuticals in surface waters can reach in average 10 µg/l, in underground waters – 1 µg/l. This results in bioaccumulation of most common medicines in the tissue of fish and other aquatic organisms. In the process of drinking water purification pharmaceuticals are removed in the processes of coagulation, filtration, activated carbon adsorption, chlorination and ozonation. Quite a number of medicines cannot be completely eliminated. As a result in many countries they are detected in drinking water in concentrations from several nanograms to 1 µg/l. For the moment there is a lack of reliable data on the toxicological effect of pharmaceuticals present in water environment; however this issue is extensively investigated.

Key words

potable water , wastewater , natural water , pharmaceuticals , toxicological effect , biodegradation , activated sludge adsorption

Microplastics – a new threat for the aquatic environment? (review)

Summary

Plastic debris components with a size from microns to meters are found in the pelagic and benthic zones of all the seas and oceans. Fine plastic fractions get to the municipal wastewater treatment facilities and water treatment plants with water and wastewater after pretreatment. By microplastics particles with a size less than 5 mm are implied. By origin they are classified as primary and secondary. Microplastic materials that are a part of industrial products are classified as primary; the secondary microplastics are formed as a result of bigger microplastics fragmentation. In municipal wastewater secondary microplastics prevail in the form of fibers; their concentration can reach 100 particles/l. Incomplete removal of microplastics at the treatment facilities is considered an accepted fact. Effluent discharge results in the rivers becoming the main source of these pollutants entering seas and oceans. The growth trend of sea water pollution with microplastics is considered absolute. Besides, the tendency of their reduction in size is noted. Microplastics are characterized by bioaccessibility for the wide range of marine biota. In animal organisms microplastics can cause physical damages or become sources of toxic impact as a result of monomers and different additives used in the production of plastics migrating from their structure. High sorption activity of microplastics in the sea water is also noted; it results in the concentration of resistant organic substances in them sixfold exceeding the concentration in sea water. High probability of bioaccumulation and trophic transfer of a whole number of toxic substances adsorbed by microplastics exists.

Key words

treatment facilities , toxicological effect , aquatic environment , primary and secondary microplastics , sorption activity