1. Department of Chemistry and Physics, College of Natural and Apllied Sciences, Sokoine University of Agriculture, P. O. Box 3038, Morogoro, Tanzania
2. Toxicology Laboratory, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark Universitetsparken 2, DK-2100 Copenhagen, Denmark
3. UNESCO National Commission of the United Republic of Tanzania, Magogoni Street, P. O. Box 20384, Dar es Salaam, Tanzania
4. Department of Veterinary Medicine and Public Health, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P. O. Box 3015, Morogoro, Tanzania