Characterizing shipboard bilgewater effluent before and after treatment

Operational discharges from oceangoing vessels, including discharges of bilgewater, release oil into marine ecosystems that can potentially damage marine life, terrestrial life, human health, and the environment. Bilgewater is a mix of oily fluids and other pollutants from a variety of sources onboard a vessel. If bilgewater cannot be retained onboard, it must be treated by an oily water separator before discharge for larger ocean-going vessels. We evaluated the effectiveness of bilgewater treatment systems by analyzing land-based type approval data, collecting and analyzing shipboard bilgewater effluent data, assessing bilgewater effluent concentrations compared to regulatory standards, evaluating the accuracy of shipboard oil content monitors relative to analytical results, and assessing additional pollution reduction benefits of treatment systems. Land-based type approval data were gathered for 20 treatment systems. Additionally, multiple samples of influent and effluent from operational bilgewater treatment systems onboard three vessels were collected and analyzed, and compared to the land-based type approval data. Based on type approval data, 15 treatment systems were performing below 5 ppm oil. Shipboard performance measurements verified land-based type approval data for the three systems that were sampled. However, oil content monitor readings were more variable than actual oil concentration measurements from effluent samples, resulting in false negatives and positives. The treatment systems sampled onboard for this study generally reduced the majority of other potentially harmful pollutants, which are not currently regulated, with the exception of some heavy metal analytes.     

Oxidation states of uranium in depleted uranium particles from Kuwait

The oxidation states of uranium in depleted uranium (DU) particles were determined by synchrotron radiation based mu-XANES, applied to individual particles isolated from selected samples collected at different sites in Kuwait. Based on scanning electron microscopy with X-ray microanalysis prior to mu-XANES, DU particles ranging from submicrons to several hundred micrometers were observed. The median particle size depended on sources and sampling sites; small-sized particles (median 13 microm) were identified in swipes taken from the inside of DU penetrators holes in tanks and in sandy soil collected below DU penetrators, while larger particles (median 44 microm) were associated with fire in a DU ammunition storage facility. Furthermore, the (236)U/(235)U ratios obtained from accelerator mass spectrometry demonstrated that uranium in the DU particles originated from reprocessed fuel (about 10(-2) in DU from the ammunition facility, about 10(-3) for DU in swipes). Compared to well-defined standards, all investigated DU particles were oxidized. Uranium particles collected from swipes were characterized as UO(2), U(3)O(8) or a mixture of these oxidized forms, similar to that observed in DU affected areas in Kosovo. Uranium particles formed during fire in the DU ammunition facility were, however, present as oxidation state +5 and +6, with XANES spectra similar to solid uranyl standards. Environmental or health impact assessments for areas affected by DU munitions should therefore take into account the presence of respiratory UO(2), U(3)O(8) and even UO(3) particles, their corresponding weathering rates and the subsequent mobilisation of U from oxidized DU particles.     

西安夏季大气亚微米颗粒物化学组成与来源的在线观测研究

西安作为汾渭平原地区最大的城市,大气颗粒物污染形势严峻.2017年夏季期间,在西安市浐灞生态园区运用气溶胶化学组分监测仪,对大气亚微米颗粒物中的非难挥发性组分(NR-PM1)进行了在线监测.观测期间NR-PM1的平均质量浓度为(30.1?±?15.4)μg???m?3.其中有机物含量最高,占NR-PM1总质量浓度的63％,其次为硫酸盐(18％)、铵盐(10％)和硝酸盐(9％).运用正交矩阵因子分析法共解析出两个主要因子,包括烃类有机组分(HOA)和含氧有机组分(OOA),分别占有机物总质量浓度的43％和55％.HOA主要由机动车排放贡献,而OOA主要由气态污染物的二次反应生成.气象因素对NR-PM1的浓度与化学组分的影响较为显著.高硝酸盐阶段发生在高湿、低温条件,可能是由氮氧化物的液相反应产生的.高硫酸盐阶段发生在低湿、高温条件,主要来自于大气光化学反应的贡献.该研究结果为西安及周边地区的空气污染治理决策提供重要的理论依据.     

Oxidation states of uranium in DU particles from Kosovo

The oxidation states of uranium contained in depleted uranium (DU) particles were determined by synchrotron radiation based micro-XANES, applied to individual particles in soil samples collected at Ceja Mountain, Kosovo. Based on scanning electron microscopy (SEM) with XRMA prior to micro-XANES, DU particles ranging from submicrons to about 30 microm (average size: 2 microm or less) were identified. Compared to well-defined standards, all investigated DU particles were oxidized. About 50% of the DU particles were characterized as UO2, the remaining DU particles present were U3O8 or a mixture of oxidized forms (ca. 2/3 UO2, 1/3 U3O8). Since the particle weathering rate is expected to be higher for U3O8 than for UO2, the presence of respiratory U3O8 and UO2 particles, their corresponding weathering rates and subsequent remobilisation of U from DU particles should be included in the environmental or health impact assessments.     

Depleted uranium particles in selected Kosovo samples

Selected soil samples, collected in Kosovo locations where DU ammunition was expended during the 1999 Balkan conflict, have been investigated by secondary ion mass spectrometry (SIMS), X-ray fluorescence imaging using a micro-beam (micro-XRF) and scanning electron microscopy equipped with an energy dispersive X-ray fluorescence detector (SEM-EDXRF), with the objective to test the suitability of these techniques to identify the presence of small DU particles and measure their size distribution and the 235U/238U isotopic ratio (SIMS). Although the results do not permit any legitimate extrapolation to all the sites hit by the DU rounds used during the conflict, they indicated that there can be "spots ' where hundreds of thousands of particles may be present in a few milligrams of DU contaminated soil. The particle size distribution showed that most of the DU particles were <5 microm in diameter and more than 50% of the particles had a diameter <1.5 microm. Knowledge on DU particles is needed as a basis for the assessment of the potential environmental and health impacts of military use of DU, since it provides information on possible re-suspension and inhalation.     

Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo

Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content (234U, 235U, 236U, 238U, 238Pu, (239 + 240)Pu). The analyses were conducted using gamma spectrometry (235U, 238U), alpha spectrometry (238Pu, (239 + 240)Pu), inductively coupled plasma-mass spectrometry (ICP-MS) (234U, 235U, 236U, 238U) and accelerator mass spectrometry (AMS) (236U)). The results indicated that whenever the U concentration exceeded the normal environmental values (approximately 2 to 3 mg/kg) the increase was due to DU contamination. 236U was also present in the released DU at a constant ratio of 236U (mg/kg)/238U (mg/kg) = 2.6 x 10(-5), indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured 238Pu/(239 + 240)Pu, could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU).     

Properties,use and health effects of depleted uranium (DU): a general overview

Depleted uranium (DU), a waste product of uranium enrichment, has several civilian and military applications. It was used as armor-piercing ammunition in international military conflicts and was claimed to contribute to health problems, known as the Gulf War Syndrome and recently as the Balkan Syndrome. This led to renewed efforts to assess the environmental consequences and the health impact of the use of DU. The radiological and chemical properties of DU can be compared to those of natural uranium, which is ubiquitously present in soil at a typical concentration of 3 mg/kg. Natural uranium has the same chemotoxicity, but its radiotoxicity is 60% higher. Due to the low specific radioactivity and the dominance of alpha-radiation no acute risk is attributed to external exposure to DU. The major risk is DU dust, generated when DU ammunition hits hard targets. Depending on aerosol speciation, inhalation may lead to a protracted exposure of the lung and other organs. After deposition on the ground, resuspension can take place if the DU containing particle size is sufficiently small. However, transfer to drinking water or locally produced food has little potential to lead to significant exposures to DU. Since poor solubility of uranium compounds and lack of information on speciation precludes the use of radioecological models for exposure assessment, biomonitoring has to be used for assessing exposed persons. Urine, feces, hair and nails record recent exposures to DU. With the exception of crews of military vehicles having been hit by DU penetrators, no body burdens above the range of values for natural uranium have been found. Therefore, observable health effects are not expected and residual cancer risk estimates have to be based on theoretical considerations. They appear to be very minor for all post-conflict situations, i.e. a fraction of those expected from natural radiation.