On Characters Of PCP And HCB Pollution And Desorption In Dagu Drainage River, Tianjin

For the very first time, this paper analyses POPs contaminations of the sediment as well as suspended particulate matter (SPM) and water samples collected from 14 sites in Dagu Drainage River in Tianjin, one of the largest metropolises in China. Based on the microprocesses of dynamic desorption and adsorption-desorption equilibriums, distribution characters and differences of POPs in 3 phases of river are explored, and the souces of POPs are retrospected consequently. For the sake of the public health, a health risk-based assessment is developed.POPs concentration, TOC, DOC, granularity and pH value are all analyzed as the basal data..As the preparation for the coming investigation, a method for the simultaneous determination of pentachlorophenol (PCP) and hexachlorobenzene (HCB), the two main typical persist organic pollutants (POPs), in river sediments and water is established. Frozen-dried sediments analytes and river water samples are pre-treated by ultrasonic wave extraction and acetyl derivation, followed by Florisil solid-phase-extraction cleanup(Florisil SPE Cleanup),and then detected by gas chromatography–mass spectrometry (GC/MS). In alkaline water condition, PCP is acetylated followed by extraction from complicated liquid matrixes. Finally, PCP and HCB are completely separated on Florisil column in both river water and sediment samples. The results show that this method can meet all the requirements for determination of POPs.Taking HCB as an example, the partition-desorption character of POPs is observed. The factors effecting desorption of HCB in the sediment are discussed carefully in the experiment and the desorption kinetics model is established accordingly. HCB will have larger desorption quantity if the temperature, degree of disturbing increases and the granularity and TOC decreases. The desorption rule of hexachlorobenzene accords with one order kinetics equation.