The Role of Arbuscular Mycorrhizal Fungi (AMF) and Petrophilic Bacteria for Remediation of Petroleum Contaminated Soil

Abstract

Ragam kondisi hutan primer dan hutan bekas tebangan menunjukkan adanya perbedaaan struktur, komposisi jenis, nilai potensi, tingkat mortalitas, alih tumbuh (ingrowth) dan pertumbuhan tegakan. Perkembangan pemodelan dinamika hutan dalam berbagai studi kuantitatif sering mengalami hambatan heterogenitas dan kompleksitas terhadap hutan itu sendiri (keragaman karakteristik tegakan dan variasi kondisi) dan keterbatasan atau ketiadaan data yang bersifat jangka panjang. Penelitian ini mencakup dimensi kuantitatif tegakan yang meliputi dimensi statis (nilai kuantitatif pada suatu waktu), dimensi dinamis (nilai kuantitatif yang mendeskripsikan fungsi waktu) dan dimesnsi spasial (nilai kuantitatif sebaran tutupan hutan) pada variasi kondisi tegakan di areal hutan alam produksi berdasarkan runtun waktu. Tujuan penelitian ini adalah mendapatkan metode untuk mengukur tingkat keterpulihan hutan Dipterocarpacea campuran setelahpenebangan menuju bentuk hutan alam primer yang tumbuh di tempat itu. Penelitian dilaksanakan si stasiun penelitian hutan Labanan yang terletak di Kabupaten Berau Propinsi Kalimantan Timur pada bukan Oktober 2012- April 2013. Desain plot penelitian berupa plot permanen yang dibangun pada tahun 1990, dengan ukuran plot 200 m x 200 m (4 ha) yang terbagi dalam 4 subplot dengan ukuran 100 m x 100 m (1 ha). Masing-masing subplot dibuat sub-plot berukuran 20 m x 72 m sebanyak 25 buah dengan 7 variasi kondisi hutan alam dengan total luas 72 ha. Pengukuran dimensi tegakan dan validasi data dilaksanakan secara periodik setiap dua tahun. Risalah perlakuan berupa variasi teknik penebangan (penebangan ramah lingkungan dengan limit diameter 50 cm/RIL 50, RIL 60 dan penebangan konvensional) dan variasi teknik pembebasan (sistematis dan berbasis pohon binaan)

Activities of petroleum production such as drilling, production, and am.sportation of petroleum products have caused negative impacts, ie land and wa er pollution either directly or indirectly. Petroleum hydrocarbon compounds · ave toxic, carcinogenic, mutagenic characteristics, and have potential to ccumulate in the food chain and human fat tissue which can lead to eurotoxicity. The environmental stresses caused by the oil spill make the soil to ndergo physical, chemical, and biological changes. Oil seeping into the soil may ause oxygen supply stop, water supply required by plants was inhibited, impaired ·lant growth, and death of soil microorganisms. There are three methods that can e conducted as remediation of contaminated soil, which are physical, chemical, an biological approach. Physical and chemical methods are ways of handling petroleum contamination that take a relatively short time, but these methods are exgensive and can cause environmental damage. Biological handling is one of the alternatives in efforts to degrade the oil content in the environment. The biological way to restore the environment of contaminated environment using plants is known as phytoremediation. One of the successes of a plant species in the remediation of contaminated soil is due to the interaction among plants, soils and microbial rhizosphere. The mi(!:robial rhizosphere that interact in soil are arbuscular mycorrhizal fungi (A¥f) and petrophilic bacteria. AMF supplements their life cycle with host plants and obtain carbon supplies from the plants, while petrophilic bacteria use carbon from petroleum hydrocarbons as their food sources. Compost was usually added to i e soil to improve physical and chemical properties of the soil. The general objective of this study was to obtain a phytorcmediation technique as a remediation of soil contaminated with crude oil. Stages of research that have been accomplished were: (1) Site characterization at illegal oil exgloitation and development of indigenous microbes; (2) The effect of nutrients, compost, and local bacteria in bioremediation of petroleum contaminated soil; (3) Adaptation selection of plants for utilization in phytoremediation of soil contaminated by crude oil; and (4) Phytoremediation of soil contaminated by crucle oil using arbuscular mycorrhizal fungi and compost. The study of 'site characterization at illegal oil exploitation and development of indigenous microbes' (Chapter 3) was conducted in three stages: 1) Site characterization at illegal oil exploitation, 2) Total petroleum hydrocarbon (TRH) measurement, and 3) Enrichment and multiplying bacteria. The total petroluem hydrocarbon (TPH) value diversed in the location, frorr.. a TPH mimimum of 0.02% to maximum of 14.73%. There were 5 locations with TPH > o, such as collector site-I (6.03%), well-2 (8.23%), well-3 (1.33%), and g lector site-2 (2% and 14.73%). Besides exploring bacterial consortium, ching, and multipying indigenous bacteria, collecting of plants that survive ound oil wells were also carried out. There were IO plants collected and entified from 5 families, namely Poaceae (Axonopus compressus, Chrysopogon

aciculatus, Eragrostis nutans, and lmperata cylindrica), Cyperaceae (Fimbristylis acuminata, Pycreus polystachyos, and Pycreus polystachyos), Gleicheniaceae Dicranopteris linearis), Lycopodiaceae (Lycopodiella cernua), and Melastomaceae (Melastoma malabathricum). In the study 'the effects of nutrients, compost, and local bacteria on the lfloremediation of petroleum contaminated soils' (Chapter 4), three levels of total R - tr©leum hydrocarbons (TPH) have been carried out (TPH-5, TPH-8, and TPH­ m petroleum contaminated soil as well as biostimulation with the addition of n trients, compost, and bioaugmentation by microbes for 19 weeks. TPH adation depended on initial TPH, nutrition, and compost. The largest P. centage of TPH degradation was obtained from N3 treatment (nutrition and - H-11) of 52.1%. Bioaugmentation using local microbes did not affect TPH egr;adation. Therefore, bioaugmentation was not required if compost has been a-tled.

In the study of 'adaptation selection of plants for utilization in p oremediation of soil contaminated by crude oil' (Chapter 5), four plant species were used, Helianthus annuus, Paspalum conjugatum, Sorghum bicolor, and Tag tes erecta on three concentrations of oil-contaminated soil (TPH-0, TPH-3, and TPH-6) by evaluating the morphological and anatomical responses. The high;est growth percentage was achieved by P. conjugatum (100%). The better percentage of growth after P. con;ugatum was S. bicolor (80%), H. annuus (71%), and lastly T erecta (66%). Increased µetroleum resulted in decreasing plant heigtit, number of leaves, root length, root dry weight (OW), shoot OW, total plant OW, and stomata} density. Conversely, the higher the concentration of petr©leum, the higher the ratio of root and shoot. The decrease of TPH significantly occurred in all four types of plants for 9 weeks (79.3 - 91.1%). The high;est percentage TPH reduction was achieved by P. conjugatum of 91% in TPH-3 and 90% in TPH-6. It can be concluded that the four types of plants studied were effectively used as phytoremediators of petroleum contaminated soil. P. conjugatum and S. bicolor were recommended as phytoremediators for further research. The study of 'phytoremediation of soil contaminated by crude oil using mycorrhiza and compost' (Chapter 6) used two types of plants, namely P. conjl"gatum and S. bicolor. Three concentrations of oil-contaminated soil (TPH-0, TPH-3, and TPH-6), 2 levels of mycorrhiza (without and with mycorrhiza), and 2 levels of compost (without and with compost) were applied by evaluating the mo hological, physiological, anatomical responses, and expression of antioxidant enz){IlleS. Increased petroleum resulted in decreasing plant growth, but enhanced physiological responses and antioxidant enzymes. The apllication of growing media was postulated inhibiting positive roles of AMF in soil.