Die invloed van kopersulfaat op die ioon- en waterbalans van Bulinus [Bulinus] Tropicus [Krauss]

Abstract

A quantitive study of the influence of coppersulphate on the ion and water balance of Bulinus (Bulinus) tropicus (Krauss) has been undertaken. Laboratory reared snails and snails collected in the field have been used in this study. It has been established that a concentration range of 0,2; 1,0 and 4,0 ppm Cuso4 inflicted mortality of 4%; 49% and 92% respectively. The addition of Cuso4 ~o the external water-medium resulted in the inhibition of the sodium, chloride, calcium and water influx rates. The analysis of the blood and soft tissues (body mass minus the shell of copper treated animals showed a drop in the sodium and chloride content. In these snails the blood calcium concetration remained constant although the calcium concentration of the soft tissues decreased. Potassium analysis has shown that the blood concentration is reduced while the concentration of the soft tissues remained constant during the six hour exposure period. It has been shown that the efflux rate of sodium, chloride and calcium increased while the water efflux rate de= creased. It has been established that the blood pH value showed a drop from 7, 6 to 7,1 after addition of Cuso 4 to the water-medium. Free zing-point measurement of the blood has been made and it is found that the ∆t value decrease from -0,260 to -o,220 °C. After evaluation of the physiological data on the influence of Cuso4 on the ion and water balance of B. tropicus, the conclusion can be made that the cu2+ inhibits the active transport of sodium, chloride and calcium. The changes in the blood pH, epithelial potential and freezing point depression are the results of a malfunctional transport system as compared with the control snails used.