DISTRIBUTION OF PERSISTENT ORGANIC POLLUTANTS IN SOILS IRRIGATED WITH TREATED WASTEWATER IN BRAUNSCHWEIG, GERMANY

MUHAMMAD HIZBUL WATHON, Drs. Bambang Purwono, M.Sc, Ph.D

2014 | Tesis | S2 Ilmu Kimia

Penelitian ini dilakukan untuk menggambarkan distribusi polutan organik persisten pada tanah yang telah diirigasi oleh air limbah dari Braunschweig, Jerman selama lebih dari 50 tahun. Tanah yang tidak pernah diirigasi dengan air limbah digunakan sebagai pembanding. Tanah yang diirigasi berasal dari area yang berbeda: (1) dari lahan pertanian Volkse South dan (2) dari lahan irigasi milik WWTP. Fraksi tanah < 2 mm yang telah dikeringkan dengan udara, diekstraksi menggunakan Soxhlet, dibersihkan melalui kromatografi kolom dan dianalisis menggunakan GC/MS (SIM) untuk mendapatkan informasi mengenai distribusi vertikal polutan dan tingkat kontaminasinya. Sample telah dikarakterisasi untuk pH, massa kering (105 °C), distribusi ukuran butir (menggunakan saringan dan silinder Atterberg), dan kandungan TOC. Sample dikelompokkan sebagai tanah berpasir dan sebagian tanah pasir berlempung. pH tanah berkisar antara 3,2 hingga 6,8. Kandungan TOC pada tanah berkisar antara < LOQ hingga 36,1%. Konsentrasi ∑ 16 PAHs dan ∑ 7 PCBs di semua horizon sampel tanah yang tidak pernah diirigasi berkisar antara 12,7 hingga 1.375 dan 1,10 to 25,7 µg/kg dw, berurutan. Untuk lahan pertanian, konsentrasi ∑ 16 PAHs dan ∑ 7 PCBs berkisar antara 14,3 hingga 456 dan 1,00 to 18,5 µg/kg dw. Konsentrasi ∑ 16 PAHs dan ∑ 7 PCBs berkisar antara 12,0 hingga 4.700 dan 1,00 to 208 µg/kg dw pada tanah di lahan irigasi milik WWTP. Secara umum, rerata konsentrasi PAH dan PCB semua inti tanah (0-100 cm) meningkat dengan urutan sebagai berikut tanah yang tidak pernah diirigasi < tanah di lahan pertanian < tanah dari lahan irigasi milik WWTP. Konsentrasi ∑ 16 PAHs and the ∑ 7 PCBs memiliki kecenderungan untuk berkurang dengan bertambahnya kedalaman tanah. Tidak ditemukan bukti yang jelas bahwa konsentrasi PAH dan PCB di lahan pertanian dipengaruhi oleh aplikasi air limbah dalam jangka waktu yang lama dan terus-menerus. Untuk lahan irigasi milik WWTP, konsentrasi yang tinggi pada tanah secara jelas berhubungan dengan praktik irigasi.

This study was performed in order to investigate the distribution of persistent organic pollutants in soils, which were irrigated with treated wastewater from Braunschweig, Germany since more than 50 years. A reference soil from conifer forest where wastewater has never been applied was also analysed as a comparison. The irrigated soil was from two different areas: (1) from an agricultural soil South of the village Volkse, and (2) from irrigation fields of WWTP. In order to get information about the vertical distribution of the pollutants and their contamination levels, 10 cm horizons of soil cores of 100 cm from reference soil, sprinkling irrigated agricultural soil of Volkse South, and soils from irrigation fields of the WWTP (S34, S36a, 61, and 71), which were sieved < 2 mm and air dried, were Soxhlet extracted, cleaned up with column chromatography and finally analysed for 16 US EPA of PAHs and 7 ICES of PCBs by GC/MS (SIM). Furthermore, the samples were characterised by pH, dry mass (at 105 °C), grain size distribution (by sieving and with Atterberg cylinder), and TOC content. The samples were characterised as sandy soils and partly loamy sand soils. The pH of soil samples ranged from 3.2 to 6.8. The total organic carbon (TOC) contents in soil samples ranged from < LOQ to 36.1%. The concentration of the ∑ 16 PAHs and the ∑ 7 PCBs in all horizons of the reference soil ranged from 12.7 to 1,375 and from 1.10 to 25.7 µg/kg dw, respectively. In case of agricultural soil, the concentration of the ∑ 16 PAHs and the ∑ 7 PCBs ranged from 14.3 to 456 and from 1.00 to 18.5 µg/kg dw. Furthermore, the concentration of the ∑ 16 PAHs and the ∑ 7 PCBs ranged from 12.0 to 4,700 and from 1.00 to 208 µg/kg dw in soil from irrigation fields of WWTP. In general, the mean PAH and PCB concentrations of the whole soil cores (0-100 cm) increased in the order reference soil < agricultural soil < soils from the irrigation fields of WWTP. Concentration of the ∑ 16 PAHs and the ∑ 7 PCBs had the tendency to decrease with the depth. There is no clear evidence that the PAH and PCB concentrations in the agricultural soil are influenced by the long-term and continuous application of treated wastewater. However, in case of the irrigation fields of WWTP, the obviously higher concentrations in the soils seem to be related to the irrigation practice.

Kata Kunci : polutan organic persisten, tanah, air limbah, GC/MS