Photodegradation of chlordane in soil and water matrix using induced UV and solar light

• Main Author: Sioson, Alexander C., Jr.
• Format: text
• Language: English
• Published: Animo Repository 2005
• Subjects: Photodegradation; Chlordan; Soils—Pesticide content; Ultraviolet radiation; Environmental Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/6901
• Institution: De La Salle University

The photodegradation of chlordane in soil and water matrix using induced ultraviolet (UV) radiation and solar light was evaluated in this study. A batch photolytic reactor equipped with a low-pressure mercury lamp (17 watt) sterilight ultraviolet (UV) lamp with a supplied wavelength of 254 nm was used in the photodegradation experiments. The pesticide’s initial concentration in water was varied using three different concentrations (0.80 mg/L, 2.60 mg/L, 8.0 mg/L) and soil samples were prepared at three different dosages (0.20 mg/kg, 2.0 mg/kg, 4.0 mg/kg). At preferred time intervals, samples were withdrawn from the reactor. The pH and temperature of the samples were continuously monitored. The photoproducts resulting from samples with different exposure times were extracted using solid-phase extraction (SPE) and the degradation of its components was verified using gas chromatography equipped with an electron capture detector (GC-ECD) set-up. Solar experiments were conducted during the month of April and May (140 33.971’N, 1200 59.515’E); peak summer period of the year in the Philippines with a mean sunlight intensity of 85187.5 lux. Results of the photodegradation experiments using the batch photolytic reactor showed an average of 91.65% degradation of the chlordane pesticide dissolved in water after eight (8) hours of exposure to UV light. High degradation efficiencies were achieved at higher chlordane initial concentrations. For solar photodegradation experiments, an average of 71.59% degradation was achieved. Photodegradation in soil showed an average of 62.54% degradation of the compound. As such, percentage degradation increases as the initial concentration of the pollutant increases. Further, solar photodegradation experiments in soil samples showed an approximate 56.35% degradation of the compound throughout the duration of the experiment. Chloride-ion analysis using high-performance liquid chromatography (HPLC) equipment was conducted at chlordane aqueous solution. Experiments were performed with artificial irradiation using the photoreactor to assure stable conditions of light intensity in the reactor. At higher chlordane concentrations, higher chloride ion concentrations in the solution were achieved. As such, more chloride ions detached themselves from the parent compound every two (2) hours of sampling time and soon vi reached an almost steady state concentration at a maximum exposure time of eight (8) hours. Experimental results of the study would be valuable in understanding the fate and behavior of chlordane pesticides in the environment, as well as in deciding remedial measures on contaminated sites and for treatment and disposal of chlordane - containing products.