本文選題：有機氯農藥　切入點：顫蚓　出處：《中國農業(yè)大學》2017年博士論文

【摘要】：大部分有機氯農藥屬于持久性污染物,具有疏水性、生物累積性、持久性和長距離遷移性等,雖然已被禁用幾十年,但在各種環(huán)境介質中仍有檢出,如食物網(wǎng)、沉積物、水和空氣等,此外,一些有機氯農藥具有手性特征,手性污染物的對映異構體在環(huán)境中可能表現(xiàn)出不同的環(huán)境行為,尤其是在生物體內這個大的手性環(huán)境下,對映異構體通常會表現(xiàn)出不同的毒性毒理、生物活性及富集代謝等行為,有時甚至表現(xiàn)出截然相反的生理效應。因此,研究有機氯農藥的環(huán)境行為及毒性效應,有助于全面理解其環(huán)境歸趨情況,并做出正確的風險評估。在此基礎上,我們選取顫蚓這種特殊的底棲生物進行研究,顫蚓對水質和底質兩方面污染反應都很敏感,可以綜合地反映出水體和沉積物的污染情況及污染物毒性。顫蚓作為食物鏈中重要的一環(huán),可以被許多魚類捕食,如錦鯉,錦鯉處于食物鏈中間位置,利于評估污染物的生物放大效應及環(huán)境風險�；谶@兩種研究生物,我們主要研究了 4種HCH異構體,DDT及其代謝物DDD和DDE,其中α-HCH和o,p,-DDT、o,p'-DDD為手性農藥。圍繞HCH異構體我們開展了以下研究,1.HCH異構體經(jīng)水暴露在顫蚓體內的選擇性行為及其毒性效應,研究發(fā)現(xiàn)顫蚓對HCH異構體有較強的富集及消除能力,但對α-HCH對映體無選擇性富集消除,且HCH異構體對顫蚓有一定的毒性效應,均可導致顫蚓體內MDA含量增加,引發(fā)氧化損傷從而對顫蚓健康造成不利影響。2.HCH異構體經(jīng)沉積物暴露在顫蚓體內的選擇性行為,研究發(fā)現(xiàn)在顫蚓體內,HCH異構體富集趨勢呈M型,這種富集趨勢可能與顫蚓尾部的自割和再生有關,顫蚓的存在可以加速沉積物中HCH異構體的耗散,對環(huán)境中HCH異構體的消除具有重要意義,同時,顫蚓可以選擇性的富集α-HCH對映體。3.顫蚓擾動作用對HCH異構體向沉積物中轉移和分布影響,研究發(fā)現(xiàn)顫蚓可以加速上層水中β-HCH向沉積物中轉移。4.HCH異構體經(jīng)水暴露在顫蚓-錦鯉食物鏈中的選擇性行為,研究發(fā)現(xiàn)顫蚓與錦鯉體內HCH異構體富集趨勢相似,但顫蚓富集HCH異構體的能力強于錦鯉,且HCH異構體經(jīng)食物鏈向上傳遞,產(chǎn)生生物放大效應;在錦鯉排泄物中發(fā)現(xiàn)較高濃度的HCH,這將對其它生物產(chǎn)生風險,致使HCH重新進入食物鏈;顫蚓和錦鯉體內HCH異構體的消除較快,半衰期小于2.5天;同時,顫蚓選擇性富集、消除α-HCH對映體,導致錦鯉中出現(xiàn)選擇性,這種選擇性可能會改變污染物對生物的毒性效應。圍繞DDT我們開展了以下研究,1.不同暴露途徑及生物效應對錦鯉富集DDT行為的影響,研究發(fā)現(xiàn)不同暴露途徑影響DDT及其代謝物(DDD和DDE)在錦鯉體內的富集代謝行為,同時,顫蚓和錦鯉可以選擇性的富集代謝o,p'-DDT和o,p'-DDD對映體。2.DDT經(jīng)食物鏈暴露在錦鯉體內組織分布及其毒性效應,研究發(fā)現(xiàn)DDT及其代謝物(DDD和DDE)在錦鯉體內不同組織中的濃度變化趨勢不同,且對錦鯉組織有一定的毒性效應,其中錦鯉的鰓和腎臟是主要的靶器官。
[Abstract]:Most of the organochlorine pesticides are persistent pollutants, with hydrophobic, bioaccumulation, persistence and long distance migration, although has been disabled for decades, but in various environmental media are still positive, such as food, water and air, sediment, in addition, some organochlorine pesticides with chiral characteristics the enantiomers of chiral pollutants may exhibit different environmental behavior in the environment, especially in the organism the chiral environment, enantiomers often exhibit different toxicological, biological activity and accumulation of metabolic behavior, sometimes even showing the opposite physiological effects. Therefore, environmental behavior and toxic effects of organochlorine pesticides, contribute to the comprehensive understanding of the environmental fate, and make proper risk assessment. Based on this, we selected t.tubifex this special research of benthos The tubifex on water and sediment pollution in two reactions are very sensitive and can reflect the situation of pollution and toxicity of pollutants in water and sediment. Tubifex as an important link in the food chain, can be a lot of fish predation, such as Koi, Koi in the middle of the food chain, for assessment of pollutants the amplification effect and environmental risk. These two kinds of biological research based on, we mainly study the 4 isoforms of HCH, DDT and its metabolites DDD and DDE, the alpha -HCH and O, P, -DDT, O, p'-DDD around the HCH isomers of chiral pesticides. We carried out the following studies, 1.HCH isomers by exposure to water selective behavior in tubifex and its toxic effects, study found that tubifex has the strong ability of accumulation and elimination of HCH isomers, but the alpha -HCH selectivity of enantiomerically enriched and eliminate HCH isomers on tubifex have toxic effects, which can lead to Increase the content of MDA in tubifex, causing oxidative damage to health caused by adverse effects on tubifex.2.HCH isomers by sediment exposure in selective behavior in tubifex tubifex, found in vivo, HCH isomer enrichment trend was M type, this trend may be related to autotomy and regeneration enrichment of tubifex tubifex tail. The presence of HCH can accelerate the dissipation of heterogeneous sediments in the body, is of great significance, for the elimination of HCH in heterogeneous environment. At the same time, tubifex can selectively enriched alpha -HCH enantiomer.3. Tubificid bioturbation effect on HCH isomers to the sediment transfer and distribution effect, study found that tubifex can accelerate the upper water P -HCH to the sediment transfer of.4.HCH isomers by water selective exposure behavior in the food chain - Koi in tubifex tubifex, found in HCH and Koi isomers enrichment trend is similar, but the tubifex enrichment of HCH isomers The ability to carp and HCH isomers through the food chain to transfer, to produce biological amplification; found that higher concentration of HCH in Koi excretions, which will produce a risk to other organisms, causing HCH to enter the food chain; tubifex and Koi in vivo HCH isomers eliminated more quickly, the half-life is less than 2.5 day; at the same time, selective enrichment of tubifex, elimination of alpha -HCH enantiomers, leading to selective appear Koi may change, the selective toxicity of pollutants on organisms around DDT. We carried out the following studies, effects of 1. different exposure pathways and biological effects on Koi enriched DDT behavior, the study found that different exposure pathways affected by DDT and its metabolites (DDD and DDE) and in vivo metabolic behavior, enrichment of carp and Koi, tubifex can metabolize o selective enrichment, p'-DDT and O, p'-DDD enantiomers.2.DDT through the food chain exposure in Koi tissues Distribution and toxicity, studies have found that DDT and its metabolites (DDD and DDE) of different concentration changes in different tissues in vivo and Koi, had certain toxic effects on koi carp tissues, the gills and kidneys are the main target organs.

【學位授予單位】：中國農業(yè)大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TQ450.261

【參考文獻】

相關期刊論文 前1條

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本文編號：1703087