Distributions and sources of polycyclic aromatic hydrocarbons in surface sediments from the Cross River estuary,S.E. Niger Delta,Nigeria

Polycyclic aromatic hydrocarbon (PAH) analyses of surface sediments from the Cross River estuary by gas chromatography–mass spectrometry indicated natural diagenetically derived PAHs in the upper estuary, with minor and variable amounts of petrogenic and combustion-derived PAHs from human activities (lower estuary). The occurrence of significant amounts of perylene (average 23% of all PAHs) with the diagenetic natural PAHs in the middle estuary bordered by mangrove forests supports its origin from terrestrial organic matter. The natural PAHs represent the highest percentage (average 76%) of the total PAHs in this tropical environment. The traditional geochemical parameters, including the petrogenic PAHs, confirmed trace petroleum contamination in the estuary. Specific PAH ratios such as Fl/Py and Fl/(Fl+Py) also support this source contribution.     

A comparison of emission calculations using different modeled indicators with 1-year online measurements

The overall measurement of farm level greenhouse gas (GHG) emissions in dairy production is not feasible, from either an engineering or administrative point of view. Instead, computational model systems are used to generate emission inventories, demanding a validation by measurement data. This paper tests the GHG calculation of the dairy farm-level optimization model DAIRYDYN, including methane (CH₄) from enteric fermentation and managed manure. The model involves four emission calculation procedures (indicators), differing in the aggregation level of relevant input variables. The corresponding emission factors used by the indicators range from default per cow (activity level) emissions up to emission factors based on feed intake, manure amount, and milk production intensity. For validation of the CH₄ accounting of the model, 1-year CH₄ measurements of an experimental free-stall dairy farm in Germany are compared to model simulation results. An advantage of this interdisciplinary study is given by the correspondence of the model parameterization and simulation horizon with the experimental farm’s characteristics and measurement period. The results clarify that modeled emission inventories (2,898, 4,637, 4,247, and 3,600 kg CO₂-eq. cow^?1 year^?1) lead to more or less good approximations of online measurements (average 3,845 kg CO₂-eq. cow^?1 year^?1 (±275 owing to manure management)) depending on the indicator utilized. The more farm-specific characteristics are used by the GHG indicator; the lower is the bias of the modeled emissions. Results underline that an accurate emission calculation procedure should capture differences in energy intake, owing to milk production intensity as well as manure storage time. Despite the differences between indicator estimates, the deviation of modeled GHGs using detailed indicators in DAIRYDYN from on-farm measurements is relatively low (between ?6.4 % and 10.5 %), compared with findings from the literature.     

Growth of Lygeum spartum in acid mine tailings: response of plants developed from seedlings, rhizomes and at field conditions

Lygeum spartum is a native species in semiarid Mediterranean areas that grows spontaneously on acid mine tailings. We aimed to study the suitability of this plant for phytostabilization. L. spartum was grown from both seeds and rhizomes in acid mine tailings with various fertilizer and lime treatments. Untreated soils had a solution pH of 2.9 with high concentrations of dissolved salts (Electrical Conductivity 25 dS m(-1)) and Zn (3100 mg L(-1)). Plants grown on untreated soil had high shoot metal concentrations (>4000 mg kg(-1)Zn). Liming increased the solution pH to 5.5 and reduced the dissolved salts by more than 75%, resulting in lower shoot metal accumulation. Plants grown from rhizomes accumulated less metal than those grown from seeds. Plants collected in the field had metal concentrations an order of magnitude less than plants raised in the growth chamber. These differences may be due to the higher moisture content and homogeneous nature of the soils used in the pot experiment.     

Translocation trisomy 21 in CVS not found in embryoblast: Three different cell lines in CVS,amnion- and placental culture

Chorionic villus samples from a healthy pregnant female were obtained for first-trimester prenatal diagnosis. A translocation trisomy 21 was diagnosed. A consecutive amniocentesis revealed a normal male karyotype. At term a healthy boy was born. Cytogenetic analysis from cord blood showed a regular karyotype of 46,XY, whereas in term placenta a pathological karyotype of 47,XY,+mar was found.     

Triazines in the aquatic systems of the Eastern Chinese Rivers Liao-He and Yangtse

The results of a one-year monitoring program on the two Eastern Chinese River systems, i.e. the Liao-He and the Yangtse, with special emphasis on the presence of triazine herbicides are presented. Sediment, suspended solids and water samples from both rivers were analyzed. Additionally, recovery experiments on the SPE-in-field-enrichment procedure and the extraction methods were performed. The samples were measured by gas chromatography coupled with mass spectrometry, electron capture detection and a newly developed mu-plasma atomic emission detector. A typical result of a one-year monitoring was obtained in case of the Liao-He: During winter, at low water period, low triazine values were found. A similar situation was found in early spring. Highest concentrations of atrazine up to 1600 ng/l were found in late spring in the water samples. Maximum concentrations of atrazine, simazine, propazine, simetryn and prometryn were observed in this season as a result of the actual use of triazines. Finally, after the high water period in autumn the triazine concentrations decreased. Additionally, atrazine adsorbed on sediment (up to 2.8 ng/g) and suspended solids was determined (up to 8 ng/l) during late spring sampling. Therefore, the logarithm of the organic carbon based sorption coefficient of atrazine could be calculated. Low levels of atrazine were measured in the water of Yangtse (up to 18.3 ng/l). The concentrations from all sampling points and sampling stations of a particular sampling date were similar, which indicates a homogeneous distribution of this herbicide. Due to the high discharge rate of up to 79,000 m3/s in case of the Yangtse a considerable mass transport of up to 57.5 kg per day atrazine may take place, even at concentrations below the European drinking water limit of 100 ng/l.     

The Biological System of the Elements (BSE)--a brief introduction into historical and applied aspects with special reference on "ecotoxicological identity cards" for different element species (e.g. As and Sn)

There are different methods to estimate and predict effects of chemical elements and corresponding speciation forms in biochemistry and toxicology, including statements on essentiality and antagonisms. Two approaches are given here: (1) "identity cards" describing biologically fundamental aspects of element chemistry and (2) qualitative discussions which assume the existence of (indirect ways into) chemical autocatalysis to be essential for maintaining life and permitting reproduction. The latter method, developed by the present authors, draws upon Stoichiometric Network Analysis, a safe procedure for complexity reduction in feedback networks) and provides estimates of concentration regimes for different elements suitable for survival and reproduction. The biochemical hierarchy level considered here is that of (metallo-)proteins. Thermodynamic toxicity aspects are given in correlations with DMSO solvent affinities and thiocyanate bonding modes. Effects of antagonists and of ion substitution within metalloenzymes or of metabolic simplification can be dealt with, likewise increased sensitivities within symbiotic relationships and within carcinomas are explained which are relevant for environmental monitoring and tumour therapy, respectively.