Determination of toxicity of binary mixtures of pharmaceuticals and pesticides

Intenzivan gospodarski rast praćen porastom svjetske populacije, rezultirao je povećanjem onečišćenja voda. S ciljem očuvanja relativno ograničenih vodenih resursa, dolazi do povećanog interesa za praćenje tvari čija prisutnost u vodama predstavlja opasnost po vodeni okoliš. Među ostalim, javila se i potreba za praćenjem farmaceutika i pesticida čiji je štetni utjecaj na okoliš očekivan, a njihova kontinuirana intenzivna upotreba dovodi do povećane koncentracije u vodama. Vodeni mediji najčešće kokteli raznih onečišćivala čije zajedničko djelovanje može rezultirati antagonističkim ili sinergističkim odstupanjem s obzirom na čisti aditivnim efekt. Neovisno o tome, procjena rizika i dalje se uglavnom provodi na temelju rezultata ispitivanja toksičnosti zasebnih onečišćivala. Za potrebe istraživanja, odabrano je šest farmaceutika: azitromicin, eritomicin, karbamazepin, oksitetraciklin, deksametazon i diklofenak te četiri pesticida: alaklor, izoproturon, diuron i klorfenvinfos te je analizirana njihova zasebna toksičnost, ali i toksičnost njihovih binarnih smjesa. Toksičnost je određena prema bakterijama Vibrio fischeri, a za opis toksičnosti binarnih smjesa primijenjena su dva matematička modela: aditivni model (engl. Concentration Adition model) i model neovisnog djelovanja (engl. Independent Action model).Intensive economic growth, followed by global population growth, has resulted with increased water pollution. In order to preserve relatively limited water resources, countries all over the world have started with monitoring of potentially dangerous substances in aquatic environment. This especially relates pharmaceuticals and pesticides whose concentration in the environment is increasing due to their continuous use.. Water pollutants are mostly mixtures comprised of different pollutants whose combined impact might result with antagonistic or synergistic deviation from pure additive toxic action. Nevertheless, the risk assessment is still mainly based on results of single pollutant toxicity. Six pharmaceuticals: azithromycin, erythromycin, carbamazepine, oxytetracycline, dexamethasone, and diclofenac, and four pesticides: alachlor, isoproturon, diuron, and chlorfenvinphos were selected for this research. Their individual toxicities were determined, as well as toxicities of their binary mixtures. Toxicity was measured toward Vibrio fischeri bacteria. Two mathematical models were applied to assess mixture effect: Concentration Addition model and Independent Action model