Occurrence Of Acidic Drugs In Aquatic Environment Of Hefei City And The Oxidation Removal By Sodium Hypochlorite

With the increase of urban population, the usage of Pharmaceuticals and Personal Care Products as Pollutants (PPCPs) rises year by year. After taken by people, most of the pharmaceuticals can not been metabolize by human. Generally, only 20% to 90% of the drugs transformed to the environment as the parent drugs or primary metabolites. Recent years PPCPs have been found in the influent and effluent of wastewater treatment plants (WWTPs), surface water, groundwater, and even the drinking water all over the world. The environmental residual characteristics and chemical behaviors of the drugs have attracted more and more fouces of the researchers. This research established and developed the analytical methods for the acidic drugs in water sample and sludge sample; then investigated the occurrence of acidic drugs in aquatic environment of Hefei and evaluated the removal of acidic drugs by WWTPs. At last this research focused on the oxidation of carbamazepine by sodium hypochlorite. The main conclusions were obtained as follows:By development of the acid extraction and purification of water and sludge samples and optimization of derivatization conditions, this study finally development reliable methods for the determination for the acidic drugs in water and sludge samples. The methods are feasible and accurate. The results and the validation parameters are as follows:the best derivatization time and temperature is 40℃ and 1 hour. The recovery of C18 SPE for water samples ranges from 65.1% to 124.3%. Recovery of LSE+SPE method for sludges samples ranges from 56.3% to 126.3%. Reproducibility linearity and detection limit were also determined in the methods.Acidic drug levels in four WWTPs and main rivers in Hefei were investigated using GC/MS method. All target compounds can be detected in the WWTPs. The concerntrations of clofibrate, clofibric acid, ibuprofen, gemfibrozil, naproxen, triclosan in the influent of WWTPs were 333.58～436.43 ng/L,276.93～380.09 ng/L, 556.59～1283.99 ng/L,653.27～1171.69 ng/L,81.62～1343.86 ng/L and 204.48～1416.79 ng/L. The averageconcerntrations of clofibrate, clofibric acid, ibuprofen, gemfibrozil, naproxen, triclosan in the effluent of WWTPs were 444.23 ng/L,196.06 ng/L,50.57 ng/L,15.79 ng/L,30.47 ng/L, and 74.56 ng/L. The total amount of acidic drugs in the excess sludge was relative small (less than 5%) compared to the total amount in the effluent. However, the total quantity of sludge was also small, so the concentration of the target compounds in the sludge was much higher, and the environmental risk can not be ignored. Gemfibrozil is the highest among all the acidic drugs and ranges from 752.12 to 1429.09 ng/g. The concerntration of triclosan in the sludge rangs from 635.27 to 1334.46 ng/g. The concertration of clofibrate is the lowest and ranges from 14.04 to 51.24 ng/g. The concerntrations of clofibric acid, ibuprofen, and naproxen range from 100 to 200 ng/g.In the research of the occurrence of target compounds in the rivers of Hefei, the concerntrations range from under detect limits to 816.23 ng/L and most of the concertration less than 200 ng/L. When there is the abouchement of effluent from a WWTP, some of the drugs concerntration can rise. Although the rives have a certain removal ability of the drugs, the concertration of acidic drugs inflow to the Chaohu lake is still high. Further treatment of the effluent from WWTPs is still needed.The effect and mechanism of sodium hypochlorite oxidation on the degradation of carbamazepine in aqueous solution were studied by batch experiment. The results showed that carbamazepine could be degraded effectively by sodium hypochlorite and degradation of carbamazepine fitted well with pseudo-first-order kinetics model (R2>0.980). The degradation of carbamazepine was promoted with the decrease of pH. The results of gas chromatography-mass spectrometry (GC/MS) analysis showed that degradation products such as chlorobenzenes and a series of hydroxy compounds were formed during sodium hypochlorite oxidation of carbamazepine. The degradation pathways of carbamazepine were also discussed by the products identified. The result of TOC showed that the mineralization of carbamazepine was lower ultimately, the mineralization reached 8.33%.