An assessment of the concentrations of PCDDs/Fs in contaminated bottom sediments and their sources and ecological risk

Purpose

The purpose of the study was to determine the levels of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F), two types of persistent organic pollutant (POP), in an urban retention reservoir located in an industrial zone within a coal-mining region. It also assesses the potential ecological risk of the PCDDs/Fs present in bottom sediments and the relationship between their content and the fraction of organic matter.

Materials and methods

The sediment samples were collected from Rybnik Reservoir, located in the centre of the Rybnik Coal Region, Silesia, one of Poland’s major industrial centres. Seventeen PCDD/F congeners in the surface of the sediments were analysed using high-resolution gas chromatography and high-resolution mass spectrometry (HRGC/HRMS).

Results and discussion

The toxic equivalency (TEQ) of the PCDDs/Fs in the sediments ranged from 1.65 to 32.68 pg TEQ g^?1. PCDDs constituted 59–78% of the total PCDDs/Fs, while the PCDFs accounted for 22–41%. The pattern of PCDD/F congeners in the sediments was dominated by OCDD. However, the second-most prevalent constituents were OCDF and ∑HpCDFs in the low TOC sediment (< 10 g TOC kg^?1), but HpCDD in the rich TOC samples (> 10 g TOC kg^?1). PCDD/F concentrations in the sediment samples were 2- to 38-fold higher than the sediment quality guidelines limit, indicating high ecological risk potential. Although a considerable proportion of PCDDs/Fs in the bottom sediments from the Rybnik Reservoir were derived from combustion processes, they were also obtained via transport, wastewater discharge, high-temperature processes and thermal electricity generation. The PCDD/F concentrations were significantly correlated with all fractions of organic matter; however, the strongest correlation coefficients were found between PCDDs/Fs and humic substances. Besides organic matter, the proportions of silt/clay fractions within sediments played an important role in the transport of PCDDs/Fs in bottom sediments.

Conclusions

The silt/clay fraction of the bottom sediments plays a dominant role in the movement of PCDDs/Fs, while the organic matter fraction affects their sorption. The results indicate that the environmental behaviour of PCDDs/Fs is affected by the quantity and quality of organic matter and the texture of sediments.

     

Thrombelastography in 26 healthy horses with and without activation by recombinant human tissue factor

Objectives – To develop a standardized technique for thrombelastography (TEG) analysis in healthy adult horses, with and without the ex vivo addition of tissue factor (TF) as an activator. To determine reference intervals for TEG parameters in the horse, and to determine if traditional coagulation tests correlate with TEG. Design – Prospective, observational. Setting – Veterinary teaching hospital. Animals – Twenty‐six healthy adult horses. Interventions – None. Measurements and Main Results – Thrombelastography with (TF‐TEG) and without (TEG) the addition of TF performed by 4 operators. Coagulation profiles (prothrombin time, activated partial thromboplastin time, platelet count, fibrinogen, antithrombin, and fibrinogen degradation products) were assessed in a subset of horses. Mean values (SD) for TEG parameters in healthy horses were: reaction time (R)=17.0 minutes (3.0 min), K time (K)=5.8 minutes (2.3 min), clotting rate (Ang)=42° (14°), maximum clot strength (maximum amplitude [MA])=60.3 mm (5.7 mm), CL30=97.0% (2.0%), LY30=0.8% (0.6%), CL60=92% (5.9%), LY60=3.2% (2.5%). Mean values (SD) for TF‐TEG parameters were: R‐TF=6.6 minutes (1.4 min), K‐TF=3.1 minutes (1.0 min), Ang‐TF=50.9° (9°), MA‐TF=62.3 mm (5.1 mm), CL30‐TF=97.8% (1.6%), LY30‐TF=0.6% (0.5%), CL60‐TF=90.8% (4.2%), and LY60‐TF=3.6% (1.9%). The addition of TF decreased R and K and increased Ang. TF‐TEG had a narrower SD for R, K, Ang, CL60 and LY60 compared with TEG. Interoperator differences were reduced by the addition of TF. Regression analysis indicated a positive relationship between MA and fibrinogen concentrations (P=0.02) and R‐TF time and prothrombin time (P=0.03). Conclusion – TF‐TEG using the described protocol may minimize variability in data obtained across institutions or users. However, due to the variability associated with different operators, it is recommended that each laboratory set up individual reference intervals with the personnel who will perform the assay, and that the assay protocols and data obtained are compared on a regular basis.     

Determination of growth-stage-specific crop coefficients (KC) of maize and sorghum

A ratio of crop evapotranspiration (ET_C) to reference evapotranspiration (ET_O) determines a crop coefficient (K_C) value, which is related to specific crop phenological development to improve transferability of the K_C values. Development of K_C can assist in predicting crop irrigation needs using meteorological data from weather stations. The objective of the research was conducted to determine growth-stage-specific K_C and crop water use for maize (Zea Mays) and sorghum (Sorghum bicolor) at Texas AgriLife Research field in Uvalde, TX, USA from 2002 to 2008. Seven lysimeters, weighing about 14 Mg, consisted of undisturbed 1.5 m × 2.0 m × 2.2 m deep soil monoliths. Six lysimeters were located in the center of a 1-ha field beneath a linear-move sprinkler system equipped with low energy precision application (LEPA). A seventh lysimeter was established to measure reference grass ET_O. Crop water requirements, K_C determination, and comparison to existing FAO K_C values were determined over a 3-year period for both maize and sorghum. Accumulated seasonal crop water use ranged between 441 and 641 mm for maize and between 491 and 533 mm for sorghum. The K_C values determined during the growing seasons varied from 0.2 to 1.2 for maize and 0.2 to 1.0 for sorghum. Some of the values corresponded and some did not correspond to those from FAO-56 and from the Texas High Plains and elsewhere in other states. We assume that the development of regionally based and growth-stage-specific K_C helps in irrigation management and provides precise water applications for this region.     

Air-pollution Effect and Paleotemperature Scale versus δ13C Records in Tree Rings and in a Peat Core (Southern Poland)

Water, Air, &; Soil Pollution - Carbon isotope analyses of peat profiles from the Karkonosze Mts. (SW Poland) and tree-ring cellulose from Wis?a river valley in the Kraków region (S...     

Application of the fast method to analyze the sensitivity-uncertainty of a lagrangian model of sulphur transport in Europe

A Fourier Amplitude Sensitivity Test (FAST) is applied to study uncertainty of the EMEP-W atmospheric model of long range transport of S in Europe. The FAST method requires frequency distribution of model parameters as input data and provides the following results: (i) mean value of the model output, (ii) variance of the model output which characterizes the parameter uncertainty of the model, and (iii) partial variances of the model output which are the measures of the model sensitivity to uncertainties in individual input parameters. A mathematical formulation of the FAST method and approximations used in its computer implementation is presented. The application requires an extension of the original method to evaluate the model output frequency distribution for different forms of prescribed frequency distributions for parameters. The computer program allows one to apply the FAST method for an arbitrary mathematical model with different options defined by the user. Some examples of uncertainty analysis of the EMEP model using real meteorological and emission data are described and compared with results obtained by the Monte-Carlo method.     

Growth performance and meat quality from broiler chickens reared with zeolite and halloysite in feed and straw pellet

The study's aim was to analyze the effects of different levels of halloysite (H) and zeolite (Z) in feed and pellets on the growth and meat quality in chickens; 500 Ross 308 broilers were assigned to five groups (1 g, control; 2–5 g, experimental). In Groups 2–5, different proportions of Z and H in feed (25:75 ratio; 0.5% to 2%) and pellet in kg/m² (2, 0.650H; 3, 0.325H and 0.325Z; 4, 0.650Z; 5, 0.160H and 0.490Z) were used. Body weight was higher than 1 in all experimental groups, and carcass weight was higher, except for Group 2. The feed consumption was lower in Groups 3 and 5 than in Group 4. The breast muscle weight was higher in Group 3 than in the control group. In Groups 2, 3, and 5, the water holding capacity in the breast muscles was better than in Group 4 and in the leg muscles in Groups 3 and 4 than in Groups 1 and 5. Most of the tested characteristics indicate a beneficial effect of aluminosilicates in feed and litter on the growth and quality of meat.