ASSESSMENT OF THE PHYSICOCHEMICAL PROPERTIES OF PHYTOLACCA-DODECANDRA(ENDOD-S) AND NICLOSAMIDE UNDER LABORATORY AND FIELD CONDITIONS

The fate of Phytolacca dodecandra (Endod-S) and Niclosamide in aquatic systems was investigated both under laboratory and field conditions. Endod-S was observed more soluble in water (12,937.7 mg/l @ 30 degrees C) than Niclosamide (19.4 mg/l @ 30 degrees C). The octanol/water par tition coefficients (K-ow) of Endod-S and Niclosamide were 0.165 and 5 .880x10(4) respectively. Adsorption isotherm studies indicated that th e Freundlich parameters (K, n) for Endod-S were 1.60x10(-6) and 0.43 r espectively for powdered activated carbon (PAC), and 3.69x10(-12) and 0.24 respectively for silt loam soil. Similar parameters for Niclosami de were 0.02 and 4.93 respectively for PAC, and 9.85x10(-5) and 2.81 r espectively for the same soil. The adsorption coefficient (K-oc) for E ndod-S and Niclosamide was 1.60x10(-6) and 0.02 respectively for PAC, and 1.62x10(-10) and 4.34x10(-3) respectively for silt loam soil. Hydr olysis of both molluscicides occurred in distilled water buffered at p H above 7. No photolysis of Endod-S and Niclosamide was observed in wa ter after exposure to longwave UV light for 4 hr. Similarly, neither c hemical volatilized from water following 5 hr of sample aeration. Unde r field conditions, Endod-S persisted in ponds for 4 to 5 days, and Ni closamide for over 14 days. The half-lives of Endod-S and Niclosamide were 1.51 and 3.40 days respectively.