[Effect of surfactant on the evaporation of p-chloronitrobenzene and naphthalene in the turbulent process].

Effect of surfactant on the evaporation of p-chloronitrobenzene and naphthalene in the turbulent process was studied in order to understand the effect of surfactant on the evaporation of complex contaminants in dynamic water system. Sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTMAB) and polyethylene glycol sorbitan monolaurate (Tween 20) were used in the experiment. The results showed that the evaporation of p-chloronitrobenzene and naphthalene from surfactant solution in set turbulence intensity followed the first kinetic equation and all the correlation coefficients were above 0.99. The evaporative loss velocity of component was increased in dynamic water,while it decreased in surfactant solution, comparing with static pure water. The combined impact of these two factors was mainly presented promoting. When the turbulence intensity was above 39 r/min and 65 r/min respectively and the concentrations of surfactants were set from 150 mg/L to 2000 mg/L, the corresponding evaporative loss velocity of naphthalene and p-chloronitrobenzene both increased clearly. The evaporative loss velocity of p-chloronitrobenzene and naphthalene in the same turbulence intensity were decreased because of the straining ability of surfactant with the rule: CTMAB > Tween 20 > SDS. The impact of both surfactant and turbulence on naphthalene (with higher H) was more distinct than p-chloronitrobenzene (with lower H).

[Apoptosis of grass carp (Ctenopharngodon idellus) lymphocytes induced by the combination of microcystins and disinfection by-products in drinking water].

Aiming at the combined pollution of low dose microcystins (MCs) and disinfection byproducts (DBPs) in drinking water, the individual and combined cytotoxic effects of two MCs (MCLR and MCRR) and two DBP compounds (CHClBr1 and CHCl2Br) on the apoptosis of isolated grass carp (Ctenopharngodon idellus) lymphocytes were examined by using in vitro bioassays. The results showed that after 2 hours exposure to the four pollutants within the range of test concentrations, the apoptosis of isolated lymphocyte occurred, and there existed significant dose-effect relationship. The combined cytotoxic effects of 1 nmol x L(-1) MCLR or MCRR and 1-100 nmol x L(-1) CHClr2 or CHCl2Br were all of additive, and the apoptosis percent was highly correlated with the exposure dose. It was suggested that the apoptosis percent of grass carp lymphocytes could be used as an effective indicator to evaluate the cytotoxicity caused by the combined pollution of MCs and DBPs.