Depleted uranium residual radiological risk assessment for Kosovo sites

During the recent conflict in Yugoslavia, depleted uranium rounds were employed and were left in the battlefield. Health concern is related to the risk arising from contamination of areas in Kosovo with depleted uranium penetrators and dust. Although chemical toxicity is the most significant health risk related to uranium, radiation exposure has been allegedly related to cancers among veterans of the Balkan conflict. Uranium munitions are considered to be a source of radiological contamination of the environment. Based on measurements and estimates from the recent Balkan Task Force UNEP mission in Kosovo, we have estimated effective doses to resident populations using a well-established food-web mathematical model (RESRAD code). The UNEP mission did not find any evidence of widespread contamination in Kosovo. Rather than the actual measurements, we elected to use a desk assessment scenario (Reference Case) proposed by the UNEP group as the source term for computer simulations. Specific applications to two Kosovo sites (Planeja village and Vranovac hill) are described. Results of the simulations suggest that radiation doses from water-independent pathways are negligible (annual doses below 30 microSv). A small radiological risk is expected from contamination of the groundwater in conditions of effective leaching and low distribution coefficient of uranium metal. Under the assumptions of the Reference Case, significant radiological doses (>1 mSv/year) might be achieved after many years from the conflict through water-dependent pathways. Even in this worst-case scenario, DU radiological risk would be far overshadowed by its chemical toxicity.     

环境中的药物——LC-MS/MS分析地表水和地下水

成百上千的活性物质正被用于人药和兽药处方中.由于药物的广泛应用,它们的残留物可通过多种途径进入环境.虽然主要通过尿和粪便的排泄,但是药品生产中的排放也应被考虑.当抗生素用于水产业,就会产生更直接的影响.污水处理设备不能完全除去药物,因此药物会出现在地表和地下水样品中.近年来,人们对环境中药物的兴趣正在增加,需要建立一种快速、灵敏、有选择性的方法来分析水样.     

崇明东滩旱作农田土壤磷素流失及其影响因素

对采用不同施肥和地表管理方式的梨园和菜地磷素的流失进行监测,研究了崇明东滩旱作农田土壤磷素的流失负荷、流失途径及其变化规律和影响因素,并分析了不同施肥和地表管理方式对农田土壤磷素流失的影响.结果表明,旱作农田土壤磷素径流流失、渗漏流失和泥沙流失浓度均超过水体富营养化总磷浓度临界值;土壤磷素流失以泥沙流失为主,泥沙总磷流失负荷占总磷流失总负荷的70.7%～82.2%;磷素流失主要发生在6、8和10月,这3个月总磷流失负荷占全年总磷流失总负荷的71.6%～73.0%.对磷素流失影响因素的相关分析表明,旱作农田土壤磷素流失与降雨量、降雨侵蚀力、径流量、径流水中总磷浓度等因素相关显著.与常规对照方式相比较,保持表土植被、覆盖地膜和精确滴灌,可减少旱作农田径流和泥沙产生量,降低总磷流失浓度,梨园和菜地总磷流失负荷消减率分别可达20.6%和12.6%.     

Effect of cholinergic antagonists on the bradycardic response of limpets to copper

The effect of cholinergic antagonists on the bradycardia induced by waterborne copper in the Mediterranean limpet Patella caerulea was investigated by using non-invasive recording of cardiac activity of whole animals. Preliminary tests were conducted to check the role of cholinergic and serotoninergic systems in the control of heart rate of P. caerulea. Superfusing the whole limpets with carbachol (cholinergic agonist) at 5×10^–5 M produced a negative inotropic and chronotropic effect (bradycardia), while superfusion with 5-hydroxytryptamine produced a positive inotropic and chronotropic effect (tachycardia). Exposure of limpets to a solution of copper in artificial seawater (0.25 mg l^–1, 3 h) reduced their heart rate to about 80% the value recorded in copper-free water. This bradycardia was inhibited by injecting the limpets with atropine (cholinergic muscarinic antagonist) at 21 g g^–1 wet flesh weight and with benzoquinonium [cholinergic nicotinic antagonist blocking the K⁺ mediated acetylcholine (ACh) response] at 10 and 100 g g^–1 prior to copper exposure. In contrast, D-tubocurarine (cholinergic nicotinic antagonist blocking Na⁺ mediated ACh response) had no effect at 85 g g^–1. These results agree with the involvement of the cholinergic system in the bradycardic response of limpets to copper, and support the view that gastropod ACh receptors do not fit the vertebrate nicotinic–muscarinic classification.Communicated by R. Cattaneo-Vietti, Genova     

Tetrodotoxin prevents copper-induced bradycardia in gastropod limpets

Acute exposure to waterborne copper is followed by a reduction in heart rate in gastropod limpets. In order to understand the mechanism of this effect, exposure to copper (0.25 or 0.5 mg l(-1); for 3 and 6 h) was combined with an injection of tetrodotoxin (TTX, 20 microl, 0.5 or 1 microM), a natural toxin that inhibits the propagation and transmission of impulses in excitable tissues. Experiments were performed on the Mediterranean limpet Patella caerulea, using a non-invasive method for the recording of cardiac activity. TTX did not affect the bradycardic effect of the cholinergic agonist carbachol. However, this toxin significantly antagonized the bradycardia induced by 0.25 and 0.5mg l(-1) of copper exposure and prevented the acardia observed in some limpets exposed to 0.5mg l(-1) of copper for 6h. These results are consistent with the hypothesis that the inhibitory action of copper on limpet cardiac activity involves an extrinsic, cholinergic neuronal control.     

Accumulation history of radionuclides in the lichen Stereocaulon vesuvianum from Mt. Vesuvius (south Italy)

The fruticose lichen Stereocaulon vesuvianum, growing on the slopes of Mt. Vesuvius (south Italy), was used as a biomonitor of 134Cs, 137Cs, 103Ru and 106Ru derived from the April 26 1986 Chernobyl nuclear reactor accident. Samples were taken at five different quotes (370, 490, 580, 780 and 960 m a.s.l.) and four successive dates (October 1986, December 1986, October 1987 and May 1999). At the first sampling, the concentrations (as Bq kg(-1) dry weight) ranged between 460 and 1020 for 134Cs, 1330 and 2500 for 137Cs, 90 and 200 for 103Ru and 360 and 710 for 106Ru, values generally lower in respect to those measured in soil and higher plants. Of the total 137Cs measured only 14% was due to 1950s and 1960s nuclear weapons tests fallout. Highest average activities of all nuclides were observed at the quote of 960 m and significant correlation (0.7相似文献   

Cross-sectional biomonitoring study of pesticide exposures in Queensland,Australia, using pooled urine samples

A range of pesticides are available in Australia for use in agricultural and domestic settings to control pests, including organophosphate and pyrethroid insecticides, herbicides, and insect repellents, such as N,N-diethyl-meta-toluamide (DEET). The aim of this study was to provide a cost-effective preliminary assessment of background exposure to a range of pesticides among a convenience sample of Australian residents. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n = 24 pools of 100 specimens). Concentrations of urinary pesticide biomarkers were quantified using solid-phase extraction coupled with isotope dilution high-performance liquid chromatography–tandem mass spectrometry. Geometric mean biomarker concentrations ranged from <0.1 to 36.8 ng/mL for organophosphate insecticides, <0.1 to 5.5 ng/mL for pyrethroid insecticides, and <0.1 to 8.51 ng/mL for all other biomarkers with the exception of the DEET metabolite 3-diethylcarbamoyl benzoic acid (4.23 to 850 ng/mL). We observed no association between age and concentration for most biomarkers measured but noted a “U-shaped” trend for five organophosphate metabolites, with the highest concentrations observed in the youngest and oldest age strata, perhaps related to age-specific differences in behavior or physiology. The fact that concentrations of specific and non-specific metabolites of the organophosphate insecticide chlorpyrifos were higher than reported in USA and Canada may relate to differences in registered applications among countries. Additional biomonitoring programs of the general population and focusing on vulnerable populations would improve the exposure assessment and the monitoring of temporal exposure trends as usage patterns of pesticide products in Australia change over time.     

Linking mean pore velocity and dispersivity to pore velocity distribution by advection–dispersion and stream tube modeling

Environmental Fluid Mechanics - A large set of experimental solute tracer breakthrough data (corresponding to more than 350 individual tracer breakthrough curves) in eight granular filter...     

Viscoelastic Characterization and Degradation Stability Investigation of Poly(butylene-adipate-co-terephthalate) – Calcium-Phosphate Glass Composites

Journal of Polymers and the Environment - In this work new biodegradable composite materials based on poly(butylene-adipate-co-terephthalate) (PBAT) reinforced with water-soluble calcium-phosphate...