| Owing to their toxicity (such as highly mutagenic and carcinogenic features) and widespread distributions in the global environment,persistent organic pollutants (POPs) have attracted the attention of environmental chemists,toxicologists and regulatory agencies for almost three decades.lt is the concerned of global environmental problems.Eight provinces and cities (Guizhou,Guangxi, Chongqing,Yunnan,Hunan,Hubei,Sichuan,Guangdong) are karst areas in the south of China. Subterranean river is one of the most important karst phenomena in these areas.lt is also a unique form of groundwater storage.With the special terrain or physiognomy,Karst area has much ecological vulnerability and easiness to be contaminated.But few reports for POPs in karst area is documented at home and abroad.This article takes the karst subterranean rivers as study site in typical karst area,fix on ubiquitous organic chlorinated pesticides (OCPs) as aim compound and explore its source,change rule,migration characteristics and its influencing factors in subterranean rivers.So as to expose the distribution and the characteristics, in order to improve the environment of POPs in karst subterranean river system.Therefore enhance the comprehensions on environmental behaviors and adscription of POPs.It is not only provided theoretical basis and the reference for polluted rivers in southwest karst area but also is an indication of the scientific outlook on development, which promotes the harmonious development of man and nature.The first section of the thesis studied and analyzed the hydrochemistry type and characteristics of two karst subterranean rivers.There are different ion concentrations between the two rivers,but its main cations are Ca2+ and Mg2+,main anion is HCO3-,other ions content are very small,so the hydrochemistry type of two rivers are HCO3-Ca and HCO3-CaMg.Ca2+,Mg2+and HCO3-in the water are mainly related with the geological background in the study areas,while SO42-and Cl-ions are mainly related with the local human activities.The second section of the thesis studied the distribution and source of OCPs in the karst subterranean river system.Through the analysis of samples in different seasons of karst subterranean rivers,it is found that OCPs concentration distribution is affected by many factors and it has obvious seasonal characteristics.Through the analysis of the cave drip water,it is found that OCPs concentration distribution maybe have a certain relationship with the distance of the drip to caves' entrance and the different environments where the drip drops.Through the OCPs analysis of algae of the Jila underground river,it is found that algae has different organochlorine pesticides compared with underground rivers and their sediments.The main components of organochlorine pesticides are DMDT and mirex, but no HCHs and DDTs.Studies on the OCPs of the sediment column of karst underground river have shown that OCPs enrichs obviously on the surface of the sediment.Through the determination of 14C age of sedimentary column of underground river,we can calculate the underground river sediment deposition rate is about0.7mm/year.The third section of the thesis studied on the factors of the distribution and source of OCPs in the sediments.The suspended particles and surface sediment scanning electron microscopy and energy spectrum showing that elements in suspended particles and surface sediment both contain elements are simiiar.Si and O elements are the main components,Al, Fe, Ca elements also accounted for certain proportion, in addition the K and Ti are for small amounts.There may be mineral feldspar,quartz and chlorite in suspended matter.The concentration of OCPs in the suspension particle is higher than that in the corresponding sediments.Moreover,the content of organic matter is an important factor to OCPs concentration distribution of the superficial deposit.Through the comparison and analysis on concentration of OCPs in the karst subterranean rivers water, surface sediment,algae of inlet and outlet and sedimentary column,discussing the migration features.Suspended particulate, sediment and aquatic organisms and temperature, precipitation, etc, are important influencing factors of OCPs migration of karst subterranean river system.
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