外因性內分泌干擾物質可氯丹及靈丹對多齒新米蝦之毒性研究

Abstract

為了瞭解內分泌干擾物質chlordane (可氯丹)及lindane (靈丹)的影響，本論文選擇遍部東亞及夏威夷島溪流中的多齒新米蝦(Neocaridina denticulata；後稱 米蝦)來進行慢性毒及生殖毒等相關研究。實驗主要將米蝦曝露於亞致死濃度之chlordane (1及10ng/L)及lindane (0.1及1μg/L)下進行。慢性毒性研究中，觀察曝露chlordane及lindane後，米蝦血淋巴之血液生化質、成長速率、脫殼時間、耗氧量(QO2)、排氨量(ENH4+)、氧氮比(O：N ratio)及組織病變等變化情形。慢性毒實驗結果顯示chlordane及lindane均會抑制成長及改變脫殼時間，並使曝露初期各試驗組的耗氧量上升，實驗後期的第14至28天，各試驗組的耗氧量則會逐漸回復正常值。試驗初期，組織切片中觀察到鰓及肝胰臟等病變，到了試驗末期，米蝦對chlordane及lindane的毒性有些許恢復的跡象。由慢性毒性試驗的結果可知，米蝦於曝露初期受到亞致死濃度之chlordane (1及10ng/L)及lindane (0.1及1μg/L)的毒性影響，但是其毒性影響14天至28天後有減弱，甚至於恢復的現象。生殖毒性研究結果中發現，chlordane及lindnae會造成米蝦體內17β-estradiol上升、testosterone下降及引發vitellogenin合成，同時也造成雌蝦孵化率下降及雄蝦生殖特徵改變。由此結果可以很明確的判斷兩種有機氯殺蟲劑極有可能以類雌性素的內分泌干擾物質影響米蝦體內荷爾蒙變化。由本論文的結果瞭解，低濃度的chlordane及lindane對米蝦造成相當大的影響，而其影響除了慢性毒害外還有類雌性素的內分泌干擾物質的毒害。經由本論文之研究可以推知，在降低chlordane及lindane對環境污染及減少環境衝擊等相關議題提供更確實及完整的資訊。

The purpose of this study was to investigate the chronic and reproductive toxicity of chlordane and lindane as well as their endocrine disruption effect on Green Neon Shrimp (Neocaridina denticulata), a common habitant in freshwater system of eastern Asia and Hawaii. In this study, the very low experimental concentrations 1 and 10 ng/L of chlordane and 0.1 and 1 μg/L of lindane were used, and biochemical composition change in hemolymph, growth rate, duration of molt cycle, oxygen consumption (QO2), ammonia-N excretion (ENH4+), the O:N ratio and histopathology were examined. Results indicated that the hypoglycemia hemolymph, retarded growth rates, and the altered duration of molt cycle had also been marked shown. In all treatments, we also found that QO2 was increased in the first few days, then it gradually returned to normal during the latter part of the experiment from days 14 to 28. Tissue damage, such as gill and hepatopancreas alterations, induced by chlordane and lindane were also observed. But, it gradually recovered to normal from days 14 to 28. It is shown that response of lower concentrations of both chlordane and lindane toxic to N. denticulata, can be self tolerated, recovered and adapted. In reproductive toxicity the reproductive alterations, morphological changes and reproductive hormone levels were clearly observed. According to our findings, an increase in 17β-estradiol, a reduction in testosterone, on induction of a vitellogenin-like protein, reduction in percentage of hatch, and morphological alternations of the masculine appendage were significtly noticed in both chlordane- and lindane-treated shrimp. Further, an endocrine disruption effect, such as estrogen-like hormone, on N. denticulata was demonstrated. The findings of demonstrate in this study could help to increase of obtain the more presages of contributive information for low concentration of chlordane and lindane.