Raspodela odabranih lekova i pesticida u sistemu voda-sediment

Abstract

Cilj ovog rada bio je ispitivanje načina adsorpcije i raspodele odabranih lekova i pesticida između vodene faze i sedimenta, kao i određivanje stepena adsorpcije i desorpcije na sedimentu reke Dunav. Rezultati adsorpcije leka karbamazepina i pesticida atrazina, karbendazima i karbofurana pokazuju najbolje slaganje sa Frojndlihovom izotermom, što ukazuje na reverzibilnu adsorpciju. Zbog visokog procenta desorpcije karbamazepina, atrazina i karbendazima, njihovo prisustvo u sistemu voda-sediment je očekivano, dok se karbofuran očekuje u manjoj koncentraciji u vodi, zbog nižeg procenta desorpcije. Lengmirov model opisuje monoslojnu adsorpciju pesticida dimetoata. Ovaj pesticid pokazuje i mali stepen desorpcije, što ukazuje na to da se može akumulirati u sedimentima u visokoj koncentraciji. Adsorpcija lekova trimetoprima, metoprolola i lorazepama se može opisati linearnim modelom. Ovi analiti pokazuju veliki afinitet adsorpcije i mogu se vezati za sediment u koncentracijama većim od ispitivanih. Za razliku od metoprolola i lorazepama, trimetoprim se u velikom procentu desorbuje sa sedimenta, pa se ovaj analit očekuje u vodi. Lekovi bromazepam, eritromicin i amlodipin su pokazali skoro potpunu adsorpciju na sedimentu i veoma mali stepen desorpcije, pa je njihova akumulacija u sedimentima očekivana.

The aim of this study was investigation of the adsorption and distribution of the selected pharmaceuticals and pesticides between water phase and sediment, as well as determination of the adsorption and desorption extent using sediment of the Danube River. Adsorption data of the drug carbamazepine and pesticides atrazine, carbendazim and carbofuran fit well to Freundlich isotherm, implying reversible adsorption. Due to high desorption extent of carbamazepine, atrazine and carbendazim, their presence in water-sediment system is expected, whereas lower desorption level of carbofuran indicates lower expected concentration of this pesticide in water. Langmuir model describes monolayer adsorption of pesticide dimethoate. This pesticide also shows low desorption extent, indicating its high accumulation in sediments. Adsorption data of pharmaceuticals trimethoprim, metoprolol and lorazepam fit fine to the linear model. These analytes show high adsorption affinity and can be adsorbed onto sediment at concentrations higher than tested. Unlike metoprolol and lorazepam, trimethoprim exhibits higher desorption level, so it is expected in water. Pharmaceuticals bromazepam, erythromycin and amlodipine displayed almost complete adsorption onto sediment and extremely low desorption rate, so their accumulation in sediments is expected.