Distribution of polycyclic aromatic hydrocarbons in the sea water column

The most intensive traffic in the world is going in the Baltic Sea. Consequences of intensive navigation are illegal or accidental oil spills. Following a spill, the soluble fraction of polycyclic aromatic hydrocarbons (PAH) is rapidly released into the water column. These remain dissolved in seawater over an extended period of time, even should the insoluble fraction be removed. Therefore, it is necessary to know how fast and what polycyclic aromatic hydrocarbons start releasing from the film of spilled oil. During an experiment, it was aimed to determine maximal concentrations of that. PAH were analysed in the dissolved and suspended phases in the water column. The study was undertaken under controlled conditions so as to minimize the variability of environmental factors such as temperature and hydrodynamics. After two weeks of the experiment, the following low-molecular weight hydrocarbons were detected: naphthalene (Naph), phenanthrene (Phe) and anthracene (Antr). No high-molecular weight hydrocarbons were detected within the total time of the experiment (8 weeks). The distributions of PAHs were measured in the dissolved and suspended phases, where total concentration of PAHs ranged from 19.01 ng L-1 to 194.70 ng L-1 in the dissolved phase and from 5.14 to 63.92 ng L–1 in the suspended phase. The release of PAHs from the film started immediately after the spill reaching 194.70 ng L-1 in the dissolved phase and 63.92 ng L-1 in the suspended phase near the bottom of water column after 1 – 2 hours. In the dissolved phase, 2 – 3 ring PAHs dominated (60 – 80 %), whereas the highest amount of 4 – 6 ring PAHs (55 – 90 %) was found in the suspended phase.

Leaching Rate of Polychlorinated Biphenyls (PCBs) from Marine Paint Chips

Polychlorinated biphenyls (PCBs) were added to certain marine vessel bottom paints as a plasticizer to improve the adhesion and durability of the paint. The most common PCB formulation used to amend such paints was Aroclor 1254. Fugitive Aroclor-containing paint chips generated from vessel maintenance and repair operations represent a potential source of PCB contamination to sediments. Limited published studies indicate that Aroclor-containing paint is largely inert and exhibits low PCB leaching into water; however, the rate and degree of leaching of PCBs from paint chips have not been directly studied. This laboratory-based study evaluated the rate and extent of leaching of PCBs from paint chips into freshwater. The results of this investigation demonstrate that the rate of PCB dissolution from paint chips decreased rapidly and exponentially over time. Based on this study, it is estimated that the rate of leaching of PCBs from paint chips would cease after approximately 3 years of exposure to water. When all leachable PCBs were exhausted, it is estimated that less than 1% of the mass of PCBs in the paint chips was amenable to dissolution. The results of this experiment suggest that Aroclor-containing paint chips found in sediments are likely short-term sources of dissolved-phase PCB to pore or surface waters and that the majority of the PCBs in paint chips remain in the paint matrix and unavailable for partitioning into water. Graphic Abstract

Faktor Risiko Penyakit Dekompresi Pada Nelayan Penyelam Di Pulau Barrang Lompo

Decompression sickness is a disorder or disease caused by the release and increase of gas bubbles from the dissolved phase in blood or tissue due to the pressure drop that is often experienced by diving fishermen. Symptoms include dizziness, joint pain, paralysis, and even death. This study aimed to determine the risk factors of decompression disease in divers in Barrang Lompo Island. This study used a Case-Control Study design. The study population was all divers with 15-64 years of age, either suffering or not suffering decompression sickness. The research subjects were 47 cases and 94 controls obtained by accidental sampling. The results showed that the depth of diving (OR = 2.641; Cl 95% = 1.285-5.428), frequency of diving (OR = 4.067; Cl 95% = 1.939-8.531), and length of diving (OR = 3.872; Cl 95% = 1.657-9.052) were the risk factors of the decompression disease incidence on divers in Barrang Lompo Island. It is suggested to divers and all members who participate in the search to prepare a dive plan according to procedures related to depth, frequency, and duration of dives to reduce the incidence of decompression sickness.

The 79°N Glacier cavity modulates subglacial iron export to the NE Greenland Shelf

Approximately half of the freshwater discharged from the Greenland and Antarctic Ice Sheets enters the ocean subsurface as a result of basal ice melt, or runoff draining via the grounding line of a deep ice shelf or marine-terminating glacier. Around Antarctica and parts of northern Greenland, this freshwater then experiences prolonged residence times in large cavities beneath floating ice tongues. Due to the inaccessibility of these cavities, it is unclear how they moderate the freshwater associated supply of nutrients such as iron (Fe) to the ocean. Here, we show that subglacial dissolved Fe export from Nioghalvfjerdsbrae (the ‘79°N Glacier’) is decoupled from particulate inputs including freshwater Fe supply, likely due to the prolonged ~162-day residence time of Atlantic water beneath Greenland’s largest floating ice-tongue. Our findings indicate that the overturning rate and particle-dissolved phase exchanges in ice cavities exert a dominant control on subglacial nutrient supply to shelf regions.

Explaining the physiological cationic distribution in erythrocytes: The murburn perspective

Living cells are characterized by the interesting disparity in the distribution of monovalent and divalent cations, as per the order: K+ > Na+ > Mg2+ >> Ca2+. Classical biologists attribute this to energy-expended and affinity-driven processes mediated by membrane-embedded proteins. Independent physicists had proposed ionic adsorption at various interfaces and/or differences in hydration shell characteristics of the ions as the reasons for the same Herein, human erythrocytes are considered as a simple ‘living cell’ model. Energy metabolism-based outcomes (murburn equilibriums) and the dissolved-phase proteins’ innate ability to bind/adsorb ions selectively are suggested as the integral rationale for the observed phenomenon.

Estimation of Polycyclic Aromatic Hydrocarbons Pollution in Mediterranean Sea from Volturno River, Southern Italy: Distribution, Risk Assessment and Loads

This study reports the data on the contamination caused by polycyclic aromatic hydrocarbons (PAHs) drained from the Volturno River. The seasonal and spatial distribution of PAHs in water and sediment samples was assessed. The 16 PAHs were determined in the water dissolved phase (DP), suspended particulate matter (SPM), and sediments. A multidimensional statistical approach was used to identify three pollution composite indicators. Contaminant discharges of PAHs into the sea were calculated in about 3158.2 kg/year. Total concentrations of PAHs varied in ranges 434.8 to 872.1 ng g−1 and 256.7 to 1686.3 ng L−1 in sediment samples and in water (DP + SPM), respectively. The statistical results indicated that the PAHs mainly had a pyrolytic source. Considering the sediment quality guidelines (SQGs), the water environmental quality standards (USEPA EQS), and risk quotient (RQ), the Volturno River would be considered as an area in which the environmental integrity is possibly at risk.

Quantification of Microplastics in North-Western Mediterranean Harbors: Seasonality and Biofilm-related Metallic Contaminants

The Mediterranean Sea is one of the most impacted basin in terms of microplastics pollution. Land-based activities are the major sources of plastic litter to the ocean, with harbors probably representing significant hotspots. In the framework of the SPlasH! project (Stop alle Plastiche in H2O, Interreg Marittimo project), microplastics were sampled in three north-western Mediterranean harbors during summer and winter. In this study, the areal concentrations of microplastics ranged from 5,576 to 379,965 items.km-2. A decreasing gradient was observed from the inner to the outer zones of the studied harbors, pointing out these enclosed systems as hotspots regarding microplastic pollution. During the summer, because of an enhancement of port activities, the areal concentrations of microplastics were higher than in winter. The investigation microplastics size classes distribution in the surface waters revealed that microplastic within a size range between 300 µm and 500 µm were depleted. During this study, we assessed trace metal partitioning (Pb, Fe, Cu, V, Cd and As) between the dissolved phase and biofilm, thus highlighting concentrations within the biofilm two and six orders higher than those in the dissolved phase. This result strongly suggest trace metal bioaccumulation within the biofilm. When trace metal concentrations are normalized over the corresponding surface of microplastics and microplastics, higher values were obtained for microplastics evidencing their enhanced capacities to bioaccumulate contaminants with respect to macroplastics.

Effect of Low-Temperature Conditioning of Excess Dairy Sewage Sludge with the Use of Solidified Carbon Dioxide on the Efficiency of Methane Fermentation

This study aimed to determine the effect of the low-temperature conditioning of excess dairy sewage sludge using solidified carbon dioxide on the efficiency of methane fermentation. An increase in the solidified carbon dioxide to excess dairy sewage sludge volumetric ratio above 0.3 had no significant effect on chemical oxygen demand concentration in the dissolved phase. The highest chemical oxygen demand values, ranging from 490.6 ± 12.9 to 510.5 ± 28.5 mg·dm−3, were determined at solidified carbon dioxide to excess dairy sewage sludge ratio ranging from 0.3 to 0.5. The low-temperature conditioning caused ammonia nitrogen concentration to increase from 155.2 ± 10.2 to 185.9 ± 11.1 mg·dm−3 and orthophosphates concentration to increase from 198.5 ± 23.1 to 300.6 ± 35.9 mg·dm−3 in the dissolved phase. The highest unitary amount of biogas, reaching 630.2 ± 45.5 cm3·g o.d.m.−1, was produced in the variant with the solidified carbon dioxide to excess dairy sewage sludge volumetric ratio of 0.3. Methane content of the biogas produced was at 68.7 ± 1.5%. Increased solidified carbon dioxide dose did not lead to any significant changes in biogas and methane production. The efficiency of biogas production from unconditioned excess dairy sewage sludge was lower by 43.0 ± 3.2%. The analysis demonstrated that the low-temperature conditioning is an energetic viable technology aiding the methane fermentation process.