3 research outputs found
Interpretasi Lingkungan Pengendapan Formasi Talang Akar Berdasarkan Data Cutting dan Wireline Log pada Lapangan X Cekungan Sumatera Selatan
A sedimentary environment is a part of earth\u27s surface which is physically, chemically and biologically distinct from adjacent terrains (Selley, 1988). The study of the depositional environment is one goal of many studiesconducted for academic purpose and economically purpose in oil and gas exploration. The study of the depositionalenvironment requires a fairly comprehensive analysis as to sequencestratigraphy facies analysis to obtain detailedinterpretations or conclusions. The purpose of this study is to analyze cutting and wireline logs to determinelithology, facies and sedimentation history of theTalang Akar formation field X in South Sumatra basin. The method used to analyze the formation of depositional environment of Talang Akar field X in SouthSumatra basin is the cutting description in order to know the composition of the constituent formations. While theanalysis conducted is cutting analysis to get lithofacies interpretation, second is well log analysis method to getsubsurface data such as physical rock properties then electrofacies analysis based on gamma ray log pattern andthird is stratigraphy sequence analysis method so sea level changed can be known. Stratigraphy sequenceinterpretation did base on facies and gamma ray log pattern changed. Pratama-1 well lithology consists of shale, siltstone, very fine sandstone until medium sandstone andlimestones. While the well lithology Pratama-2 is composed of shale, very fine until medium sandstone and siltstone.Facies found in wells Pratama-1 consists of distributary channel fill, prodelta, distal bar, distributary mouth bar,and marsh. Facies in wells Pratama-2 is a mud flat and mixed flat. In Pratama-1 wells are 2 sets sequence that bounded by 2 sequence boundary, with a stratigraphic unit LST, TST and HST with progradation andretrogradation stacking patterns. While the Pratama-2 wells contained one stratigraphic unit sequence that is onlyTST in progradation and agradation stacking patterns. Based on this analysis the Talang Akar formation field X inSouth Sumatra basin has a transitional depositional environment
Influence of Humic Acid on Titanium Dioxide Nanoparticle Toxicity to Developing Zebrafish
Titanium dioxide
nanoparticle (TiO<sub>2</sub>NP) suspension stability
can be altered by adsorption of dissolved organic matter (DOM). This
is expected to impact their environmental fate and bioavailability.
To date, the influence of DOM on the toxicity of TiO<sub>2</sub>NPs
to aquatic vertebrates has not been reported. We examined the impact
of Suwannee River humic acid (HA) on the toxicity of TiO<sub>2</sub>NPs to developing zebrafish (<i>Danio rerio</i>) in the
dark and under simulated sunlight illumination. Adsorption of HA increased
suspension stability and decreased TiO<sub>2</sub>NP exposure. TiO<sub>2</sub>NPs were more toxic in the presence of HA. In the absence
of simulated sunlight, a small but significant increase in lethality
was observed in fish exposed to TiO<sub>2</sub>NPs in the presence
of HA. Under simulated sunlight illumination, photocatalytic degradation
of HA reduced suspension stability. Despite the lower concentrations
of Ti associated with fish in the treatments containing HA, under
simulated sunlight illumination, median lethal concentrations were
lower and oxidative DNA damage was elevated relative to fish exposed
to TiO<sub>2</sub>NPs in the absence of HA. This study demonstrates
the importance of considering environmental factors (i.e., exposure
to sunlight, adsorption of DOM) when assessing the potential risks
posed by engineered nanomaterials in the environment
TiO<sub>2</sub> Nanoparticle Exposure and Illumination during Zebrafish Development: Mortality at Parts per Billion Concentrations
Photoactivation of
titanium dioxide nanoparticles (TiO<sub>2</sub>NPs) can produce reactive
oxygen species (ROS). Over time, this has
the potential to produce cumulative cellular damage. To test this,
we exposed zebrafish (<i>Danio rerio</i>) to two commercial
TiO<sub>2</sub>NP preparations at concentrations ranging from 0.01
to 10 000 ng/mL over a 23 day period spanning embryogenesis,
larval development, and juvenile metamorphosis. Fish were illuminated
with a lamp that mimics solar irradiation. TiO<sub>2</sub>NP exposure
produced significant mortality at 1 ng/mL. Toxicity included stunted
growth, delayed metamorphosis, malformations, organ pathology, and
DNA damage. TiO<sub>2</sub>NPs were found in the gills and gut and
elsewhere. The two preparations differed in nominal particle diameter
(12.1 ± 3.7 and 23.3 ± 9.8 nm) but produced aggregates in
the 1 μm range. Both were taken up in a dose-dependent manner.
Illuminated particles produced a time- and dose-dependent increase
in 8-hydroxy-2′-deoxyguanosine DNA adducts consistent with
cumulative ROS damage. Zebrafish take up TiO<sub>2</sub>NPs from the
aqueous environment even at low ng/mL concentrations, and these particles
when illuminated in the violet-near UV range produce cumulative toxicity