Bull. Environ. Contam. Toxicol. (1995) 54:150-157 9 1995 Springer-Verlag New York Inc. Environmental Gontamination and Toxicology Lindane and Methylparathion Residue Degradation in Carnation Byproduct (Dianthus caryophyllus, L.) under Different Environmental Conditions J. J. Cer6n 1, A. Barba 2, M. A. Camara 2, C. Guti6rrez 1 1Dep. Patologia Animal, Facultad de Veterinaria, Universidad de Murcia, Murcia 30100, Spain 2Dep. Qu[mica Agr[cola, Geolog[a y Edafologia, Facultad de Ciencias, Universidad de Murcia, Murcia 30100, Spain Received: 1 February 1994/Accepted: 30 May 1994 Carnation plant (piantlms caryot~llus. L.) is an important ornamental cultivar in Southern Spain. A byproduct is obtained from this crop consisting mostly in leaves and stems that has a good nutritive value for animals. But pesticide contamination resulting from agriculture practices for pest control limits the safe use of this byproduct as animal feed (Cer6n, 1993). Although insecticide residues in food is causing great concern to international health authorities, most reports and research are related to products used for human consumption. A limited number of reports address residues and their degradation in vegetables destined for animal feed (Waldron and Goleman, 1969; Johnson et al., 1972; Shivankar and Ram, 1988). Lindane and methylparathion are pesticides heavily used in carnation and can produce toxic effects in animals due to the consumption of aldulterated carnation byproducts (Ceron, 1993). The purpose of this work is to study the degradation of lindane and methylparathion in carnation plant and in the carnation byproduct under different environmental conditions of storage prior to its usage as an animal feed. A knowledge of these events may provide a basis to avoid contamination of animal foods and to safely feed the carnation byproduct to animals. MATERIAL AND METHODS The carnation plants were grown at an experimental greenhouse in Los Urrutias (45 km south of Murcia, Spain), and were collected during the second year of growth. Commercial formulations of lindane (90% dust) and methylparathion (35% emulsifiable concentrate) were sprayed March 10, 1992 onto a plot measuring 10 m2 at the recommended field application rates of 0.270 kg/Ha (300 l/Ha) and 0.105 kg/Ha (300 l/Ha) respectively (Cer6n, 1993). A control plot was included for blank analysis. Correspondence to: J. J. Cer6n 150