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To investigate a suitable biological remediation approaches for anticipating oil spills in Cilacap sandy beach (Indonesia), some alternative strategies using biostimulation and a combination of biostimulation-bioaugmentation have been evaluated in inter tidal near shore Cilacap, Indonesia. The purpose of the study was to compare the efficacy of biostimulation using slow release fertilizer (SRF) only, combination of biostimulation-single strain bioaugmentation, and combination of biostimulation-consortium bioaugmentation, to enhance oil degradation. The experiment was conducted using sediment polluted 100,000 ppm Arabian Light Crude Oil in a mesocosm system for 90 days. The parameters measured were oil depletion, bacterial growth and changes in environmental conditions. The results showed that the affectivity on oil depletion of biostimulation-bioaugmentation combination was observed faster and higher than biostimulation only. At the 16 th day application, the biostimulation with the added consortium and single strain treatment, increased oil depletion percentage by 2.2 and 1.6 times that of the control, respectively. For a longer period of treatment, both of combination treatments showed similar efficacy in degrading oil contamination in sandy beach. It is proposed that combination of biostimulation-bioaugmentation with the consortium is relatively better alternative for combating oil-pollution for a short period.

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Dissolved and particulate heavy metals play a role in geochemical cycle as an agent in adsorption-desorption, deposition-resuspension, and dispersion mechanisms of heavy metals in water environment. The objectives of this research were to determine the distribution and behaviour of dissolved and particulate heavy metals Pb and Zn in different seasons (west and east seasons) at Jeneberang Estuary of Makassar. Concentrations of Pb and Zn were analysed using Atomic Adsorption Spectrophotometry based on APHA, AWWA, WEF (2005). The concentration of dissolved Pb in the riverine, estuarine, and marine waters were in the range (average) of <0.002 mg/L (below detectable limit), 0.013-0.144 mg/L (0.047 mg/L), 0.016-0.198 mg/L (0.079 mg/L); and the concen-tration of dissolved Zn were in the range (average) of <0.002 mg/L (below detectable limit), <0.002-0.014 mg/L (0.005 mg/L), <0.002-0.083 mg/L (0.017 mg/L). Meanwhile, the concentration of parti-culate Pb were in the range (average) of 1.807-2.569 mg kg-1 (2.215 mg kg-1), 0.521-1.272 mg kg-1 (0.911 mg kg-1), 0.465-2.182 mg kg-1 (1.033 mg kg-1), and the concentration of particulate Zn were in the range (average) of 19.151-90.942 mg kg-1 (51.710 mg kg-1), 16.999-63.059 mg kg-1 (31.694 mg   kg-1), 19.439-80.283 mg kg-1 (45.554 mg kg-1) in the riverine, estuarine and marine waters, respecti-vely. Behaviour of dissolved heavy metals Pb and Zn showed that the concentrations tended to increase (desorption) along the gradient of high salinity as a  result of the higher heavy metals input from coastal region than that riverine regimes.Keywords: distribution, behaviour, dissolved, particulate, heavy metal, Jeneberang Estuary

Bioremediation, involving biostimulation and/or bioaugmentation, is a promising method to overcome oil spills in Cilacap coastal waters. Cilacap coastal area has high risk on oil pollution. This study investigated the stimulatory effect of nitrogen concentration, bacterial density and the composition of bacterial culture in enhancing oil degradation in this area. The applications of 4 different concentrations of Slow Release Fertilizer (SRF) and 2 different densities of bacterial cells in the form of single (RCO/B/08_008) and mixed culture were employed in microcosm experiments for 28 days. The efficacy of combining bacterial culture and fertilizer application in various concentrations was also tested. Oil degradation, bacterial growth and environmental parameters were monitored periodically during the experiments. The results showed that oil degradation rate was more influenced by nutrient concentration (biostimulation) than bacterial number or culture composition (bioaugmentation) added. The efficacy of biostimulation in degrading oil was better than that of bioaugmentation. Biostimulation increased oil degradation up to 6.4 times higher than the control. The optimum of fertilizer concentration added was 7.5 mg N/g (C:N ratio of 1,000 : 75), which increased depletion rate both in biostimulation-only and the combination of biostimulation with bioaugmentation up to 6.4 and 7.5 times higher than the control, respectively. It is suggested that bioremediation of oil-contaminated sandy beach in Cilacap would be optimal by employing a combination of Slow Release Fertilizer at 8 concentration having C/N ratio = 1,000 : 75 and RCO/B/08_008 culture at density of 0.5 x 10 cells/mL (100% homology with Alcanivorax sp. TE-9).