Osmoregulation of the Prawn, Palaemon elegans Exposed to some Heavy Metals

重金屬對岩蝦Palaemon elegans的滲透調節之研究

陳弘成(Hon-Cheng Chen) ； Jone D. Slinn

《臺灣水產學會刊》 7卷1期 (1980/09) Pp. 1-13

https://doi.org/10.29822/JFST.198009.0001

摘要

1．本研究乃將廣鹽性岩蝦Palaemon elegans在15℃下置於不同鹽度溶液中，探討在汞、銅、鎘與鋅的作用下，其血淋巴達到穩定滲透濃度所需的時間。當岩蝦直接由20%海水，或由20%海水放入100%(34‰ s)海水中，其血淋巴馴化之時間受重金屬影嚮並不大。但在銅3ppm之溶液中者則例外，卽由20%海水放入100%海水中，其馴化時間會由正常24小時延長為約48小時。
2．雖然20%海水對此蝦來說並不造成特殊的滲透調節之壓迫，但此低濃度之海水會增加金屬對岩蝦之毒性。尤其當銅和鎘為高濃度時。
3．岩蝦在100%海水中，其血液之滲透濃度隨金屬濃度之增加而增加。但在20%及60%海水中，其濃度反而隨金屬濃度的增高而遞減。此卽表示滲透調節之能力已受損害或滲透調節之功能已受抑制。此種現象以銅溶液中者要比在鎘溶液中者更為明顯，而以在另二種重金屬溶液中者為最小。因此滲透調節的受損可被認為是由於鰓部組織受到銅、鋅及鎘等金屬所破壞的結果。但岩蝦暴露於汞溶液時其鰓部並無破壞現象。
4．當某金屬濃度使在100%海水中的岩蝦之血液滲透濃度高於1.7℃時，則此金屬濃度卽可使岩蝦慢性致死。但死亡原因並不一定是由於滲透調節的能力之受阻所引起。
5．由於在60%及100%海水中，岩蝦若剛脫殼時，其血液滲透濃度要比未脫殼者為高，但在20%的海水中，二者無顯著差異。因此重金屬對於剛脫殼岩蝦的血液滲透濃度之影響並不十分明顯。

並列摘要

1. The effects of mercury, copper, cadmium and zinc on the time to achieve a steady osmoconcentration in the haemolymph of the euryhaline prawn, Palaemon elegans were examined in different salinities at 15℃. When the prawns were directly transferred from 100% seawater (34‰ salinity) to 20% seawater and vice versa, the acclimation time was not greatly affected by the presence of heavy metals with the possible exception of 3 ppm Cu (where the time was prolonged from a normal 24 hours to about 48 hours following transfer 20% to 100% seawater).
2. Although 20% seawater did not appear to be particularly stressful to the prawns it increased the toxicity of metals, especially the higher concentrations of copper and cadmium.
3. In 100% seawater, the blood osmoconcentration increased with an increase in metal concentration, while in 20% and 60% seawaters, it decreased with increasing metal concentration, an indication of the impairment of osmoregulatory ability. This effect was more pronounced in copper than in cadmium, with zinc and mercury having the least effect. It is suggested that the impairment of osmoregulation in the prawns by copper, cadmium and zinc resulted from damage to the gill tissues, but this did not appear to be the case with prawns exposed to mecury.
4. A metal concentration which causes a rise to over 1.70℃ in the blood osmoconcentration of prawns kept in 100% seawater may he considered as a level eventually proving lethal during long term exposure, although death may not necessarily he due to impaired osmoregulatory ability.
5. The blood osmoconcentration of newly-moulted prawns in 60% and 100% seawater is higher than that of non-moulted prawns, while there is no significant difference, between the two stages in 20% seawater. However, the data are insufficient to decide whether heavy metals have any significant effect on the blood osmoconcentration of newly-moulted prawns.