Dissolved oxygen and its response to eutrophication in a tropical black water river

The Siak is a typical, nutrient-poor, well-mixed, black water river in central Sumatra, Indonesia, which owes its brown color to dissolved organic matter (DOM) leached from surrounding, heavily disturbed peat soils. We measured dissolved organic carbon (DOC) and oxygen concentrations along the river, carried out a 36-h experiment in the province capital Pekanbaru and quantified organic matter and nutrient inputs from urban wastewater channels into the Siak. In order to consider the complex dynamic of oxygen in rivers, a box-diffusion model was used to interpret the measured data. The results suggest that the decomposition of soil derived DOM was the main factor influencing the oxygen concentration in the Siak which varied between ～100 and 140 μmol l^?1. Additional DOM input caused by wastewater discharges appeared to reduce the oxygen concentrations by ～20 μmol l^?1 during the peak-time in household water use in the early morning and in the early evening. Associated enhanced nutrient inputs appear to reduce the impact of the anthropogenic DOM by favoring the photosynthetic production of oxygen in the morning. A reduction of 20 μmol l^?1, which although perhaps not of great significance in Pekanbaru, has strong implications for wastewater management in the fast developing areas downstream Pekanbaru where oxygen concentrations rarely exceed 20 μmol l^?1.     

PCDD/Fs, dioxin-like PCBs and marker PCBs in eggs of peregrine falcons from Germany

Thirty one egg samples of peregrine falcons were collected in different regions of Germany (South-West, North and East) and analysed for PCDD/Fs, PCBs and marker PCBs. Altogether, 37 PCB congeners were determined, allowing a more detailed discussion of different aspects of the relative importance of these individual congeners. For comparison with dioxin data from other studies, differences between toxic equivalency factors (TEF) have to be taken into consideration. The results of this study are discussed on the basis of WHO-TEFs for birds published in 1998. All samples showed high levels of PCDD/Fs (median of all samples: 368 pg WHO-PCDD/F-TEQ/g fat; range 137-1453) and even higher levels of PCBs (median 967 pg WHO-PCB-TEQ/g fat; range 243-7482). The upper range of these levels reach concentrations found at the beginning of the Belgian dioxin crisis when a significant reduction in hens' egg hatchability was observed. The relative contribution of PCBs to the total TEQ is on average 71% (range 55-92%) with a tendency to higher values in South-West Germany compared to different sites in East Germany or one site in northern Germany. Within a region, a wide range of contamination can be found. Even in the same cities (Stuttgart and Ludwigshafen), results derived from eggs collected in the same year (2003) varied by factors 5-10. These findings show the high degree of variation occurring even within the same kind of biological matrix. Therefore, to allow for comparison of regions or time trends, a considerable number of samples has to be analysed.     

Adaptation of a speciation sampling cartridge for measuring ammonia flux from cattle feedlots using relaxed eddy accumulation

Improved measurements of ammonia losses from cattle feedlots are needed to quantify the national NH₃ emissions inventory and evaluate management techniques for reducing emissions. Speciation cartridges composed of glass honeycomb denuders and filter packs were adapted to measure gaseous NH₃ and aerosol NH₄⁺ fluxes using relaxed eddy accumulation (REA). Laboratory testing showed that a cartridge equipped with four honeycomb denuders had a total capture capacity of 1800 μg of NH₃. In the field, a pair of cartridges was deployed adjacent to a sonic anemometer and an open-path gas analyzer on a mobile tower. High-speed valves were attached to the inlets of the cartridges and controlled by a datalogger so that up- and down-moving eddies were independently sampled based on direction of the vertical wind speed and a user-defined deadband. Air flowed continuously through the cartridges even when not sampling by means of a recirculating air handling system. Eddy covariance measurement of CO₂ and H₂O, as measured by the sonic and open-path gas analyzer, were used to determine the relaxation factor needed to compute REA-based fluxes. The REA system was field tested at the Beef Research Unit at Kansas State University in the summer and fall of 2007. Daytime NH₃ emissions ranged between 68 and 127 μg m^?2 s^?1; fluxes tended to follow a diurnal pattern correlated with latent heat flux. Daily fluxes of NH₃ were between 2.5 and 4.7 g m^?2 d^?1 and on average represented 38% of fed nitrogen. Aerosol NH₄⁺ fluxes were negligible compared with NH₃ emissions. An REA system designed around the high-capacity speciation cartridges can be used to measure NH₃ fluxes from cattle feedlots and other strong sources. The system could be adapted to measure fluxes of other gases and aerosols.     

Shifting elasmobranch community assemblage at Cocos Island—an isolated marine protected area

Fishing pressure has increased the extinction risk of many elasmobranch (shark and ray) species. Although many countries have established no‐take marine reserves, a paucity of monitoring data means it is still unclear if reserves are effectively protecting these species. We examined data collected by a small group of divers over the past 21 years at one of the world's oldest marine protected areas (MPAs), Cocos Island National Park, Costa Rica. We used mixed effects models to determine trends in relative abundance, or probability of occurrence, of 12 monitored elasmobranch species while accounting for variation among observers and from abiotic factors. Eight of 12 species declined significantly over the past 2 decades. We documented decreases in relative abundance for 6 species, including the iconic scalloped hammerhead shark (Sphyrna lewini) (?45%), whitetip reef shark (Triaenodon obesus) (?77%), mobula ray (Mobula spp.) (?78%), and manta ray (Manta birostris) (?89%), and decreases in the probability of occurrence for 2 other species. Several of these species have small home ranges and should be better protected by an MPA, which underscores the notion that declines of marine megafauna will continue unabated in MPAs unless there is adequate enforcement effort to control fishing. In addition, probability of occurrence at Cocos Island of tiger (Galeocerdo cuvier), Galapagos (Carcharhinus galapagensis), blacktip (Carcharhinus limbatus), and whale (Rhincodon typus) sharks increased significantly. The effectiveness of MPAs cannot be evaluated by examining single species because population responses can vary depending on life history traits and vulnerability to fishing pressure.     

Turner syndrome-omphalocele association: Incidence,karyotype, phenotype and fetal outcome

Objective

Omphalocele is known to be associated with genetic anomalies like trisomy 13, 18 and Beckwith–Wiedemann syndrome, but not with Turner syndrome (TS). Our aim was to assess the incidence of omphalocele in fetuses with TS, the phenotype of this association with other anomalies, their karyotype, and the fetal outcomes.

Method

Retrospective multicenter study of fetuses with confirmed diagnosis of TS. Data were extracted from a detailed questionnaire sent to specialists in prenatal ultrasound.

Results

680 fetuses with TS were included in this analysis. Incidence of small omphalocele in fetuses diagnosed ≥12 weeks was 3.1%. Including fetuses diagnosed before 12 weeks, it was 5.1%. 97.1% (34/35) of the affected fetuses had one or more associated anomalies including increased nuchal translucency (≥3 mm) and/or cystic hygroma (94.3%), hydrops/skin edema (71.1%), and cardiac anomalies (40%). The karyotype was 45,X in all fetuses. Fetal outcomes were poor with only 1 fetus born alive.

Conclusion

TS with 45,X karyotype but not with X chromosome variants is associated with small omphalocele. Most of these fetuses have associated anomalies and a poor prognosis. Our data suggest an association of TS with omphalocele, which is evident from the first trimester.     

A novel methodology to estimate the evolution of construction waste in construction sites

This paper focuses on the accumulation of construction waste generated throughout the erection of new residential buildings. A special methodology was developed in order to provide a model that will predict the flow of construction waste. The amount of waste and its constituents, produced on 10 relatively large construction sites (7000-32,000 m² of built area) was monitored periodically for a limited time. A model that predicts the accumulation of construction waste was developed based on these field observations. According to the model, waste accumulates in an exponential manner, i.e. smaller amounts are generated during the early stages of construction and increasing amounts are generated towards the end of the project. The total amount of waste from these sites was estimated at 0.2 m³ per 1 m² floor area. A good correlation was found between the model predictions and actual data from the field survey.