Heavy metal content of combustible municipal solid waste in Denmark.

Data on the heavy metal composition of outlets from Danish incinerators was used to estimate the concentration of Zn, Cu, Pb, Cr, Ni, Cd, As and Hg in combustible waste (wet as received) at 14 Danish incinerators, representing about 80% of the waste incinerated in Denmark. Zn (1020 mg kg(-1)), Cu (620 mg kg(-1)) and Pb (370 mg kg(-1)) showed the highest concentration, whereas Hg (0.6 mg kg(-1)) showed the lowest concentration. The variation among the incinerators was in most cases within a factor of two to three, except for Cr that in two cases showed unexplained high concentrations. The fact that the data represent many incinerators and, in several cases, observations from a period of 4 to 5 years provides a good statistical basis for evaluating the content of heavy metals in combustible Danish waste. Such data may be used for identifying incinerators receiving waste with high concentrations of heavy metals suggesting the introduction of source control, or, if repeated in time, the data must also be used for monitoring the impacts of national regulation controlling heavy metals. It is recommended that future investigations consider the use of sample digestion methods that ensure complete digestion in order to use the data for determining the total heavy metal content of waste.     

Long-term increase in climatic dryness in the East-Mediterranean as evidenced for the island of Samos

The Eastern Mediterranean region is among the regions which were predicted to become drier under IPCC climate scenarios. Here, we document a gradual reduction of rainfall and tree growth and the loss of rural springs during the last decades of the twentieth century. Years with severe drought are associated with very low tree growth (dendrochronology) and dry falling of springs as evidenced by interviews with local stakeholders. The paper discusses the consequences of accelerating drought on natural vegetation and agriculture and points at the interaction with fire dynamics and economy, both likely to enhance the drought effect.     

The formation of dithionate during the iron(III)-catalysed autoxidation of sulfur(IV)-oxides

The iron(III)-catalyzed autoxidation of sulfur(IV)-oxides results in the formation of two different oxidation products of sulfur(IV): dithionate, S₂O₆²⁻, and sulfate, SO₄²⁻. The yield of these reaction products depends on the experimental conditions. Under the studied conditions ([Fe(III)] : [SIV)] = 1:10, pH = 2–4) dithionate is the minor reaction product. The formation of dithionate is influenced by the initial pH but not by the initial O₂ concentration. The presence of CO²⁺, Mn²⁺, and Ni²⁺ have no influence on the yield of dithionate, whereas in the presence of Cr³⁺ less and, in the presence of Cu²⁺, no dithionate is formed.     

Copy number analysis of meiotic and postzygotic mitotic aneuploidies in trophectoderm cells biopsied at the blastocyst stage and arrested embryos

Preimplantation genetic testing for aneuploidy (PGT-A) by copy number analysis is now widely used to select euploid embryos for transfer. Whole or partial chromosome aneuploidy can arise in meiosis, predominantly female meiosis, or in the postzygotic, mitotic divisions during cleavage and blastocyst formation, resulting in chromosome mosaicism. Meiotic aneuploidies are almost always lethal, however, the clinical significance of mitotic aneuploidies detected by PGT-A is not fully understood and healthy live births have been reported following transfer of mosaic embryos. Here, we used single nucleotide polymorphism genotyping of both polar bodies and embryo samples to identify meiotic aneuploidies and compared copy number changes for meiotic and presumed mitotic aneuploidies in trophectoderm cells biopsied at the blastocyst stage and arrested embryos. PGT-A detected corresponding full copy number changes (≥70%) for 36/37 (97%) maternal meiotic aneuploidies. The number of presumed mitotic copy number changes detected exceeded those of meiotic origin. Although mainly in the mosaic range, some of these mitotic aneuploidies had copy number changes ≥70% and would have been identified as full aneuploidies. Interestingly, many arrested embryos had multiple mitotic aneuploidies across a broad range of copy number changes, which may have arisen through tripolar spindle and other mitotic abnormalities.     

Prenatal diagnosis of multiple acyl-CoA dehydrogenase deficiency: association with elevated α-fetoprotein and cystic renal changes

We report the occurrence of multiple acyl-CoA dehydrogenase deficiency (MADD) in two consecutive pregnancies in a young, Caucasian, non-consanguineous couple. In the first pregnancy, the maternal serum α-fetoprotein was elevated. A sonogram showed growth delay, cystic renal disease, and oligohydramnios; the parents decided to terminate the pregnancy. Postmortem examination confirmed the cystic renal disease and showed hepatic steatosis, raising the suspicion of a metabolic disorder. The diagnosis of MADD was made by immunoblot studies on cultured fibroblasts. In the subsequent pregnancy, a sonogram at 15 weeks' gestation showed an early growth delay but normal kidneys. The maternal serum and amniotic fluid concentrations of α-fetoprotein were elevated, and the amniotic fluid acylcarnitine profile was consistent with MADD. In vitro metabolic studies on cultured amniocytes confirmed the diagnosis. A follow-up sonogram showed cystic renal changes. These cases provide additional information regarding the evolution of renal changes in affected fetuses and show a relationship with elevated α-fetoprotein, which may be useful in counseling the couple at risk. MADD should be considered in the differential diagnosis of elevated α-fetoprotein and cystic renal disease. Early growth delay may be an additional feature. Copyright © 2001 John Wiley & Sons, Ltd.     

Mineralization of particulate organic matter derived from coral-reef organisms in reef sediments of the Gulf of Aqaba

In situ and laboratory incubation experiments in a fringing reef in the Gulf of Aqaba were performed to study degradation rates of particulate organic matter in reef sediments. Coral mucus, clam eggs, and zooxanthellae were used as model particulate organic compounds for these experiments. Aerobic and anaerobic mineralization rates were calculated by dissolved inorganic carbon (DIC) and O₂ fluxes from the sediments under different particulate organic matter additions. Fast enhancement (approximately twofold) of O₂ and DIC fluxes were found with the addition of coral mucus and clam eggs compared with control incubations without addition. Most of the degradation is believed to have occurred anaerobically rather than aerobically (DIC:O₂ ratios were 4.3-28.1). Higher degradation rates of coral mucus and clam eggs were estimated in carbonate sediment than in silicate sediment (1.2-1.6-fold), which was attributed to the different physical and chemical properties of both sediments. Our study shows the significance of the reef sediment as a suitable site for microbial degradation of particulate organic material excreted from different reef community organisms. This may increase the regeneration of nutrients in the reef environment necessary to sustain high biological productivity.     

Geospatial variability of krill and top predators within an Antarctic submarine canyon system

The spatial distribution patterns of krill, seabirds (penguin, petrel and albatross), fur seals and baleen whales were mapped in nearshore waters (<50 km from land) to investigate their habitat selection within two adjacent submarine canyons near Livingston Island, Antarctica. Three shipboard surveys were conducted (February 2005–2007), and an echosounder was used to measure the distribution and abundance of krill while simultaneously conducting visual surveys to map seabird and marine mammals. Using a multispecies approach, we test the hypothesis that spatial organization of krill and top predators co-vary according to fine-scale changes in bathymetry in the nearshore marine environment. GAMs are used to examine the effect of sea depth, slope and distance to isobaths on the spatial distribution and abundance of krill and predators. Spatial distribution patterns of krill and predators relate to fine-scale (1–10 km) changes in bathymetry and exhibit cross-shelf gradients in abundance. Krill were concentrated along the shelf-break and abundant within both submarine canyons. Predators exhibited different preferences for locations within the submarine canyon system that relates to their foraging behavior. Penguins concentrated closer to shore and within the head of the east submarine canyon immediately adjacent to a breeding colony. Whales were also concentrated over the head of the east canyon (overlapping with penguins), whereas albatrosses and fur seals were concentrated in the west canyon. Fur seals also showed preference for steep slopes and were concentrated along the shelf-break. Petrels exhibited peaks in abundance throughout both submarine canyons. Owing to their orientation, size and proximity to the coastline, submarine canyons provide important habitat heterogeneity for krill and a variety of predators. This study highlights the multispecies approach for studying spatial ecology of top predators and krill and has implications for marine spatial management of the Scotia Sea.