Micron-size tire tread particles leach organic compounds at higher rates than centimeter-size particles: Compound identification and profile comparison.

Tire tread particles (TTP) are environmentally prevalent microplastics and generate toxic aqueous leachate. We determined the total carbon and nitrogen leachate concentrations and chemical profiles from micron (∼32 µm) and centimeter (∼1 cm) TTP leachate over 12 days. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were used to measure the concentration of leached compounds. Nontargeted chemical analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) was used to compare the chemical profiles of leachates. After leaching for 12 days, DOC was 4.0 times higher in the micron TTP leachate than in the centimeter TTP leachate, and TDN was 2.6 times higher. The total GC×GC/TOF-MS chromatographic feature peak area was 2.9 times greater in the micron TTP leachate than the centimeter TTP leachate, and similarly, the total relative abundance of 54 tentatively identified compounds was 3.3 times greater. We identified frequently measured tire-related chemicals, such as 6PPD, N-cyclohexyl-N'-phenylurea (CPU), and hexa(methoxymethyl)melamine (HMMM), but nearly 50% of detected chemicals were not previously reported in tire literature or lacked toxicity information. Overall, the results demonstrate that smaller TTP have a greater potential to leach chemicals into aquatic systems, but a significant portion of these chemicals are not well-studied and require further risk assessment.

Effect of modified waste introduction methods over short-term and long-term use of onsite sanitation systems.

Insufficiently treated wastes contained within onsite sanitation systems (OSS) commonly used by disadvantaged and developing communities contribute to public and environmental health concerns, calling for practical alternative solutions. At the basic level, an improved understanding of the evolution of chemical and physical constituents under different waste introduction methods and for short-term and long-term operation is needed. While receiving non-dilute waste under mixed, unmixed, toilet paper exclusion, and urine diversion (UD) regimes, self-flushing OSS simulated using anaerobic digesters (ADs) were compared during three operational stages: (1) 0-1 month service for unsheltered encampments; (2) 1-3 month disaster relief scenario; and (3) ≥ 3 months representing refugee camps and long-term household use. Although stratification was found to promote suitable conditions for short-term use of self-flushing toilets, mixing increased beneficial biodegradation of organic constituents. Urine-containing ADs demonstrated a shift from sulfide to ammonia odor accompanied by high pH (> 8) after ~ 240 d. E. coli reduction following elevated nitrogen and dissolved solids levels pointed to decreased pathogen survival in ADs with urine. The benefits of bacterial disinfection, reduction of sulfurous odors, and heightened organics degradation in mixed, urine-containing ADs suggest this format as more desirable for prolonged use of self-flushing OSS over unmixed or urine-diverting formats.

Using submersible fluorescence sensors to track the removal of organic matter in decentralized wastewater treatment systems (DEWATS) in real time.

Decentralized wastewater treatment systems (DEWATS) using anaerobic treatment are increasingly being considered for wastewater treatment with options for non-potable water reuse at the community scale. One challenge for ensuring performance and reliability of DEWATS is the lack of suitable on-site sensors to monitor failure or contamination events. In this study, the aim was to use in situ fluorescence sensors to track the performance of a DEWATS, consisting of an anaerobic baffled reactor (ABR) coupled to anaerobic filter (AF) and constructed wetland (CW) treatment processes. A submersible in situ fluorometer equipped with tryptophan (TRP) and chromophoric dissolved organic matter (CDOM) sensors was deployed in each chamber of the ABR-AF-CW system, and results showed that TRP fluorescence was preferentially removed over CDOM fluorescence throughout the system. Significant relationships between TRP fluorescence and chemical oxygen demand (COD) also suggested that TRP fluorescence could be used as a surrogate for COD and soluble COD concentrations. Strong agreement between results obtained from the 1D in situ fluorometer and those obtained from a 3D benchtop fluorometer lends further support to the use of in situ fluorescence sensors to track DEWATS performance.

Liver transplantations in Bulgaria--initial experience.

The filed of liver transplantation (LT) continues to evolve and is highly effective therapy for many patients with acute and chronic liver failure resulting from a variety of causes. Improvement of perioperative care, surgical technique and immunosuppression in recent years has led to its transformation into a safe and routine procedure with steadily improving results. The aim of this paper is to present the initial experience of the transplant team at Military Medical Academy - Sofia, Bulgaria. For the period of April 2007 - August 2014 the team performed 38 liver transplants in 37 patients (one retransplantation). Patients were followed up prospectively and retrospectively. In 36 (95%) patients a graft from a cadaveric donor was used and in two cases--a right liver grafts from live donor. The mean MELD score of the transplanted patients was 17 (9-40). The preferred surgical technique was "piggyback" with preservation of inferior vena cava in 33 (86%) of the cases and classical technique in 3 (8%) patients. The overall complication rate was 48%. Early mortality rate was 13% (5 patients). The overall 1- and 5-year survival is 81% and 77% respectivelly. The setting of a new LT program is a complex process which requires the effort and effective colaboration of a wide range of speciacialists (hepatologists, surgeons, anesthesiologists, psychologists, therapists, coordinators, etc.) and institutions. The good results are function of a proper selection of the donors and the recipients. Living donation is an alternative in the shortage of cadaveric donors.

Dust inputs and bacteria influence dissolved organic matter in clear alpine lakes.

Remote lakes are usually unaffected by direct human influence, yet they receive inputs of atmospheric pollutants, dust, and other aerosols, both inorganic and organic. In remote, alpine lakes, these atmospheric inputs may influence the pool of dissolved organic matter, a critical constituent for the biogeochemical functioning of aquatic ecosystems. Here, to assess this influence, we evaluate factors related to aerosol deposition, climate, catchment properties, and microbial constituents in a global dataset of 86 alpine and polar lakes. We show significant latitudinal trends in dissolved organic matter quantity and quality, and uncover new evidence that this geographic pattern is influenced by dust deposition, flux of incident ultraviolet radiation, and bacterial processing. Our results suggest that changes in land use and climate that result in increasing dust flux, ultraviolet radiation, and air temperature may act to shift the optical quality of dissolved organic matter in clear, alpine lakes.

[Attempt for etiopathogenic treatment of acute superior mesenteric artery occlusion by combination of small bowel resection and percutaneous artery stenting].

Acute mesenteric ischemia secondary to arterial occlusion is a highly lethal condition, mandating early diagnosis and prompt therapy, to prevent, or at least to minimize, bowel infarction. Progress in understanding the pathophysiology of mesenteric ischaemia has led to novel methods of treatment, so that in some circumstances therapy may be purely medical. More often surgery is demanded and is frequently life saving. Percutaneous transcatheter procedures are increasingly employed in both diagnosis and treatment. Close collaboration between surgeons, radiologists, physicians and anesthesiologists is therefore necessary if clinical outcome is to be improved. This conclusion is drawn by the presented case report.

[Attempt for etiopathogenic treatment of acute superior mesenteric artery occlusion by combination of small bowel resection and percutaneous artery stenting].

Acute mesenteric ischemia secondary to arterial occlusion is a highly lethal condition, mandating early diagnosis and prompt therapy, to prevent, or at least to minimize, bowel infarction. Progress in understanding the pathophysiology of mesenteric ischaemia has led to novel methods of treatment, so that in some circumstances therapy may be purely medical. More often surgery is demanded and is frequently life saving. Percutaneous transcatheter procedures are increasingly employed in both diagnosis and treatment. Close collaboration between surgeons, radiologists, physicians and anesthesiologists is therefore necessary if clinical outcome is to be improved. This conclusion is drawn by the presented case report.

Water quality assessment and modeling of an effluent-dominated stream, the Notwane River, Botswana.

In an effort to assess current and future water quality of the only perennial river in southeastern Botswana, this study presents water quality monitoring and modeling results for the effluent-dependent Notwane River. The water quality along the Notwane River, pre- and post-implementation of secondary wastewater treatment, was compared and results demonstrated that water quality improved after the new wastewater treatment plant (WWTP) went online. However, stream standards for chemical oxygen demand, total dissolved phosphorous, and fecal coliform were exceeded in most locations and the critical dissolved oxygen (DO) reached concentrations of less than 4 mg L(-1). High dissolved P concentrations and intense macrophyte growth at the impounding ponds and at sites within 30 km of the effluent waste stream confluence suggest that eutrophication was a function of P release from the ponds. Results of DO modeling demonstrated that an unpolluted inflow at approximately 10 km downstream of the confluence was responsible for raising DO concentrations by 2.3 mg L(-1), while SOD was responsible for a decline in DO concentrations of 1.4 mg L(-1) at 6 km downstream of the confluence. Simulations also showed higher DO concentrations during winter months, when water temperatures were lower. Simulations, in which the distributed biochemical oxygen demand (BOD) loading from cattle excrement was decreased, produced nominal increases in DO concentrations. An increase in WWTP BOD loadings to projected 2020 values resulted in a 1.3 mg L(-1) decrease in the critical DO concentration. Furthermore, a decrease in treatment plant efficiency, from 94% to 70% BOD removal, produced critical DO concentrations and anoxia along much of the modeled reach. This has significant implications for Gaborone, especially if decreased WWTP efficiency occurs as a result of the expected future increase in pollutant loadings.