Identification and quantification of marine siderophores using high-performance liquid chromatography with electrospray ionization mass spectrometry

Siderophores are low-molecular-weight organic compounds (500 - 1500 Da) produced by heterotrophic bacteria and highly selective for Fe(III). These complexation of iron by siderophores has the potential to affect both the solubility and bioavailability of iron (III) in seawater. We have determined the ferrioxamine siderophores in the seawater samples from high latitude North Atlantic Ocean The identification and quantification of this siderophore type chelate was done by using recently developed high-performance liquid chromatography-mass spectrometry methods. Five different siderophore type chelates were detected and the compounds comprised of two groups; ferrioxamines and amphibactins group. In the dissolved phase, three types of hydroxamate siderophore have been identified; Ferioxamine B (FOB), Ferrioxamine G (FOG) and ferrioxamine E (FOE). Concentration of dissolved FOB, FOG and FOE are extremely low between 0–135 x 10-18 M. Our present data indicated the presence of low concentrations of dissolved siderophores in the high latitude of the Atlantic Ocean and suggest that siderophore distributions are both spatially and temporally variable

Removal of Fe ion from polluted water by reusing spent coffee grounds

High concentration of iron (Fe) levels (above 1.0 mg/L) in water causes bad taste, staining and deposition in pipes and results in high turbidity in water supplies. Existing treatment technologies (which have been conventionally applied to remove Fe ions), are expensive and cause toxic sludge production. A set of experiments was carried out to evaluate the Fe uptake potential of spent coffee grounds by conducting batch tests in an aqueous solution through a biosorption process. Batch sorption studies were conducted based on pH, contact time, adsorbent dosage and adsorbent particle size. In addition, initial metal concentration was investigated. Flame atomic adsorption spectroscopy analysis revealed that the maximum adsorption recorded was 0.470 mg g-1 by using 0.30 g of 210-355 µm coffee with the maximum uptake percentage of Fe (92.9%) for 60 minutes at pH 4. Adsorption behavior of Fe ions on a surface of coffee grounds was well-interpreted by Langmuir model (R2 = 0.999). A kinetic study indicated that the Fe ions uptake was well-fitted by the pseudo second-order reaction model with good correlation (R2 = 0.993). The study offered an affirmative answer to the hypothesis of reusing eco-friendly and low-cost coffee grounds for removal of Fe ions from polluted waters

Optimization of extraction methods and detectors for heavy metal analysis in sediment

The optimization analysis, extractions of metals (Zinc, Cadmium, Lead, and Copper) content in Certified Reference Material, BCR ®-667 of estuarine sediment was carried out by different procedures of acid digestion such hydrochloric acid-nitric acid-hydrofluoric acid, nitric acid-perchloric acid, and sulphuric acid-hydrogen peroxide mixtures. These metals concentrations were determined by using Differential Pulse Stripping Voltammetry (DPSV) and Inductive Coupled Plasma-Mass Spectrometry (ICP-MS). The purpose was to determine these metals (Zn, Cd, Pb, Cu) concentration in sediment samples simultaneously in good precision and accuracy measurement. The results showed both have small standard deviation indicates good precision of metals determinations in both detectors. The accuracy for DPSV ranged from 18.85-154.38% and ICP-MS ranged from 75.28-90.13%. Zn, Cd, Pb, and Cu were simultaneously measured in BCR ®-667. When the optimized method was applied into real sediment samples, both determinations showed a good precision in analysis but ICP-MS was selected as the detector. It measured all the metals of interest (Zn, Cd, Pb, Cu) in the real sediment sample simultaneously

Distribution of dissolved aluminium (dAl) in seawater at Pulau Perhentian, Terengganu

The distribution of dissolved aluminum (dAl) was determined in seawater collected from Pulau Perhentian in November 2015 and April 2016, in order to identify a possible effect of the Northeast monsoon on dAl. Seawater sample profiles were collected at five different stations at 4-5 different depths. The concentration of dAl was determined directly by using cathodic stripping voltammetry on the hanging mercury drop electrode. This method was optimized in order to fit the determination of dAl concentration in seawater at this study area. During the measurements in November 2015, the concentration of dAl was found to be between 31.1 μg/L and 98.7 μg/L at that surface layer, and was found to be increasing with depth. On the other hand, the concentration ranged between 30.9 μg/L and 167.3 μg/L at surface layer and decreased with depth in April 2016. This indicates that the distribution of dAl throughout the water column was different between the two periods. It suggests that there was a possible source of Al from the surface sediment due to the high current turbulence during the Northeast monsoon season in this area, as mentioned by previous studies

Distribution of dissolved and particulate Fe in an estuarine system at Bagan Pasir, Perak

The distribution of dissolved iron (dFe) and particulate iron in the estuarine system was studied where in-situ water sampling stations were selected at Bagan Pasir, Perak. The concentration of dFe was 1.17±0.28 mg/L on average at the estuary, while in freshwater samples its concentration was 0.08±0.00 mg/L. This study found that the concentration of particulate Fe in freshwater system was higher than that in the estuary system. The Fe concentration was 0.95±0.03 mg/kg and 0.80±0.18 mg/kg at the freshwater and estuary systems, respectively. We have applied a distribution coefficient (KD) in order to quantify the partitioning of Fe between the particulate (>0.45 µm) and dissolved (<0.45 µm) phases. The KD value of Fe in the freshwater system was much higher compared to that in the estuary, where the KD value was 12.18 in freshwater and 0.48 -1.31 in the estuary. This indicated that Fe in this area has a strong affinity with the particulate phase in a freshwater system and this is probably due to the anthropogenic input. On the other hand, Fe may exist in colloidal or organic ligands which probably originate from surface sediment or a biological process in water columns at the estuarine area

Growth performance of blood cockle (Tegillarca granosa) within Kongkong Laut estuaries, Masai, Johor

A non-coastal cockle farming area such as an estuaries zone might become an alternative for continuous and sustainable cockle supply in the future. The main objective of this research is to determine the growth and mortality rate of Tegillarca granosa (T. granosa) within an estuary area. Three cockle plots were allocated along the estuary area of Kongkong Laut (P1, P2, P3) based on the geographical area, from upper to lower part of estuaries. Cockle monitoring activity was conducted from August to December 2015 for both in-situ water parameters and the cockles’ growth increments. This study shows that within a brackish estuarine environment, the highest cockle growth increment was recorded within the highest water salinity trend area (26.92 ± 4.79 ppt; P2), with a shell increment of 2.70 ± 0.52 mm per month, while the lowest cockle growth increment was recorded within the lowest water salinity trend area (17.65 ± 5.73 ppt; P1) with the shell increment of 2.05 ± 0.86 mm per month. One-way ANOVA shows that there was significant difference (p<0.05) in growth increments among all sites of cockle plots, with significant positive correlation between the salinity level and the cockle’s growth rate (p<0.05, r=0.65). This indicates that salinity level within a brackish environment plays an important role towards cockle’s growth rate. Additionally, high turbidity level for a prolonged period leads to lower cockle survival rates within an area. However, further studies need to be done to look for other environmental factors that may affect cockle growth rate within an estuarine environment

Study of dissolved nutrient condition at Pulau Perhentian, Terengganu

This study compares the distribution of dissolved nutrients (NO3− and PO43−) between two seasons (pre-monsoon and post-monsoon) in Pulau Perhentian, Terengganu. The concentration of dissolved PO43− was found to be 16 to 83 times higher during the post-monsoon period (April 2015) compared to the pre-monsoon period (October 2014). On the other hand, the concentration of dissolved NO3− was two (2) to three (3) times higher during the post-monsoon period (April 2015) compared to the pre-monsoon period (October 2014). These nutrients’ inputs were converted from P limitation condition during the pre-monsoon period to N limitation condition during the post-monsoon period at our study area. The results of this study suggest that the Northeast monsoon plays an important role in influencing the distribution of dissolved nutrients between seasons in Pulau Perhentian. It is thought that during the post-monsoon period, a considerable input of nutrients from bottom water is responsible for increasing dissolved nutrients in surface water, in particular PO43−

Optimization of dissolved Fe(III) determination in coastal water by using electrochemistry approach and 2, 3- Dihydroxynaphthalene as the binding ligand

An optimization procedure was developed in this study using Competitive Ligand Exchange-Adsorptive Cathodic Stripping Voltammetry (CLE-AdCSV) to determine the concentration of dissolved Fe(III) in coastal water collected at Pulau Redang, Terengganu. The method was optimized for the UV-irradiation period for dissolved organic digestion, while the pH of the samples prior to UV-irradiation was determined. Additionally, the types and concentrations of the artificial ligands, followed by the sample equilibration period for sample measurements, were confirmed and performed. A small standard deviation of 0.002 was obtained in this experiment, indicating that the data obtained were precise when the optimized method was applied. Those optimized method was applied to the samples at Station 3, and the data obtained were compared with the previous study. Our present data showed that the concentration of dissolved Fe(III) was low, approximately 6 - 82 times lower than previously reported data. As our study area was affected by the Northeast monsoon (NEM), the phenomenon of strong turbulence during the post-monsoon event could have caused the resuspension of bottom sediment to the upper layer of seawater. Hence, the total suspended solids (TSS) level could have increased in the water column, suggesting that Fe(III) was mainly attached to the particulate phase rather than during the dissolved phase

Physico-chemical assessment of water resources in Pulau Pangkor, Perak, Peninsular Malaysia

The main aim of this investigation was to assess the water resource in Pulau Pangkor in terms of physico-chemical characteristics. The river flow represents the physical characteristics while the chemical characteristics represent by selected water quality parameters namely temperature, pH, electrical conductivity, salinity, total dissolved solids, dissolved oxygen, turbidity, total suspended solids, biochemical oxygen demand, ammoniacal-nitrogen and chemical oxygen demand. The study was carried out during the scientific expedition from 15th -21st July 2017. Based on accessibility, ten sampling locations were selected for the purpose of water resource assessment. At each sampling station, the river water velocity, depth of water, river cross-sectional area were measured and later the data were used to estimate the river discharge. The river water quality status were assessed using Harkin’s Index. The results showed that the river water velocity ranges from 0.1 to 0.6 m/second with an estimated discharge ranges from 121 to 1244 m3/day. Based on Harkin’s Index, the water quality index ranges from 0.016 (Class I) to 0.216 (Class II) where eight sampling locations fall under Class I and the remainder fall under Class II. In conclusion the water bodies from all sampling locations are of high quality status