THE DYNAMICS OF DELTAMETHRIN IN SOILS FROM YOGYAKARTA SPECIAL TERRITORY

Syukria Kurniawati, Prof. Dr. Narsito

2011 | Tesis | S2 Ilmu Kimia

Deltametrin merupakan bahan aktif insektisida piretroid sintetik yang saat ini semakin banyak digunakan untuk mengontrol hama pengganggu tanaman. Penggunaan deltametrin secara intensif pada lahan pertanian akan menyebabkan adanya akumulasi dan munculnya residu pada tanaman dan lahan pertanian. Meningkatnya residu deltametrin dalam jangka waktu lama akan menggangu kesetimbangan ekosistem dan menimbulkan permasalahan di lingkungan. Oleh sebab itu, perlu dilakukan penelitian tentang dinamika deltametrin di lingkungan tanah untuk mengevaluasi tingkat keamanan dan keefektifan penggunaan deltametrin pada lahan pertanian. Telah dilakukan penelitian untuk mengetahui dinamika insektisida deltametrin dalam tanah yang diperoleh dari tiga lokasi di Daerah Istimewa Yogyakarta (DIY): Pakem, Wonolelo dan Glagah. Dinamika yang dipelajari meliputi sorpsi, retensi dan mobilitas serta disipasi. Batch experiments digunakan pada studi sorpsi sedangkan kolom tanah digunakan untuk mempelajari retensi dan mobilitas deltametrin dalam tanah. Penentuan DT50 dilakukan dengan menempatkan 500 mg tanah yang telah diberi deltametrin pada media berlapis alumunium foil. Tanah kemudian dijemur selama 30 hari. Sampel tanah diambil pada 0, 1, 2, 3, 5, 7, 10, 20 dan 30 hari setelah aplikasi. Hasil penelitian menunjukkan bahwa isoterm sorpsi deltametrin mengikuti model adsorpsi Freundlich (r 2 =0,999). Semakin tinggi kandungan organik tanah, kekuatan sorpsi deltametrin semakin besar. Pada studi kolom tanah (kedalaman 30 cm), jarak pelindian relatif pendek pada ketiga jenis tanah. Deltametrin terdeteksi di kedalaman 5-10 cm pada 2, 5 dan 10 hari setelah aplikasi pada kolom tanah. Laju disipasi deltametrin ketiga tanah pada kondisi gelap dipengaruhi oleh aktivitas mikroba sedangkan di bawah sinar matahari, beberapa faktor mempengaruhi disipasi diantaranya aktivitas mikroba, penguapan dan fotodegradasi.

Deltamethrin is a synthetic pyrethroid and one of the most widely used insecticide for crop protection. Intensive use of deltamethrin on the agricultural land will cause potential accumulation and appearance of residues in crops and soil environment. Increasing deltamethrin residues in the long term will disrupt the ecosystem balance and cause environmental problems. Therefore, the dynamics and behavior of deltamethrin in soil environments should be investigated to evaluate the level of safety and effectiveness of insecticide deltamethrin in agricultural activities. Laboratory trials were conducted to investigate the dynamics of the insecticide in soils obtained from three different areas in Yogyakarta Special Territory: Pakem, Wonolelo and Glagah, including the sorption, the retention, the mobility, and the dissipation. Batch experiments were carried out in the sorption study whereas soil column were used to study the retention and mobility of deltamethrin in soils. DT50 determinations were carried out by placing 500 mg soils which were deltamethrin has been applied on media covered with alumunium foil. The soils were sun exposed for 30 days. Soil samples for deltamethrin analysis were collected after 0, 1, 2, 3, 5, 7, 10, 20 and 30 days of application. Sorption isotherm of deltamethrin follows the Freundlich adsorption model (r 2 =0.999).The stronger deltamethrin sorption were observed for soils with higher content of organic matter. In soil column studies (30 cm soil depth), cumulative leaching was generally low, and deltamethrin were detected at 5-10 cm depth in soils within 2, 5 and 10 days. Microbial activitiy appeared to dominate the dissipation process in the dark conditions whereas under the sunexposure conditions, several factors affect the dissipation including microbial activity, volatilization and photolysis.

Kata Kunci : deltametrin, dinamika, tanah