Serum concentrations of indicator PCB congeners in the Czech adult population

In 2006, levels of seven indicator polychlorinated biphenyl congeners (PCB28, 52, 101, 118, 138, 153, and 180) in blood serum of 202 blood donors residing for more than 2 years in five urban areas included in the Czech Human Biomonitoring project were measured by GC/MS/MS method. PCB congeners 138, 153 and 180 accounted for about 97% of the sum of the indicator congeners analyzed. Overall, the median and 95th percentile of the most abundant congener PCB 153 were 438 ng/g lipid and 1079 ng/g lipid, respectively. The highest median levels were found in Uherské Hradiste (669 ng/g lipid) and Ostrava (672 ng/g lipid in males compared to 341 ng/g lipid in females). Serum PCB concentrations were significantly associated with age, gender, place of residence and smoking habit, but not with body mass index and education. The results suggest the importance of PCB body burden in the Czech general population and the existence of hot spots.     

Salt marsh vegetation change in response to tidal restriction

Vegetation change in response to restriction of the normal tidal prism of six Connecticut salt marshes is documented. Tidal flow at the study sites was restricted with tide gates and associated causeways and dikes for purposes of flood protection, mosquito control, and/or salt hay farming. One study site has been under a regime of reduced tidal flow since colonial times, while the duration of restriction at the other sites ranges from less than ten years to several decades. The data indicate that with tidal restriction there is a substantial reduction in soil water salinity, lowering of the water table level, as well as a relative drop in the marsh surface elevation. These factors are considered to favor the establishment and spread ofPhragmites australis (common reed grass) and other less salt-tolerant species, with an attendant loss ofSpartina-dominated marsh. Based on detailed vegetation mapping of the study sites, a generalized scheme is presented to describe the sequence of vegetation change from typicalSpartina- toPhragmites-dominated marshes. The restoration of thesePhragmites systems is feasible following the reintroduction of tidal flow. At several sites dominated byPhragmites, tidal flow was reintroduced after two decades of continuous restriction, resulting in a marked reduction inPhragmites height and the reestablishment of typical salt marsh vegetation along creekbanks. It is suggested that large-scale restoration efforts be initiated in order that these degraded systems once again assume their roles within the salt marsh-estuarine ecosystem.     

Case report: a prenatal case of Jarcho–Levin syndrome diagnosed during the first trimester of pregnancy

The Jarcho–Levin syndrome is a specific form of spondylocostal/spondylothoracic dysostosis. There have been various classifications of this syndrome. We present the case of a severe prenatal Jarcho–Levin syndrome, diagnosed by ultrasound examination during the first trimester of pregnancy in a family with no previous medical history of an affected child. X-ray exploration, high-resolution spiral computed tomography and autopsy confirmed the diagnosis. Copyright © 2003 John Wiley & Sons, Ltd.     

Levels of PCDDs, PCDFs, and PCBs in the blood of the non-occupationally exposed residents living in the vicinity of a chemical plant in the Czech Republic

In 2003, concentrations of altogether 17 PCDD/Fs congeners and 12 non-ortho and mono-ortho dioxin-like PCBs were measured in the blood of 60 randomly selected adults who lived in three settlements surrounding a chemical plant that had been producing chlorinated herbicides (mainly HCHs, HCB, pentachlorophenole, 2,4,5-T) in the 1960's; subjects consuming home-produced animal foods were chosen. Twenty blood donors with similar characteristics from the locality with about 80 km distance were used as control subjects. The factors that influenced the dioxin levels were investigated on the basis of a questionnaire. The aim of our study was to find out whether the residents living in the surroundings of the chemical plant are at a greater exposure risk than the controls. To calculate TEQ values, WHO-TEFs were used. The concentrations of four PCDD and six PCDF congeners were below the LOD in more than 50% of samples. Significantly higher WHO-TEQ levels (p<0.05) were found for PCDDs, PCDFs, or PCBs in all three followed up groups compared with controls. The geometric means of the total TEQ values for PCDD/F/PCBs were 43.8, 50.2, and 40.0 pg/g fat compared to 23.2 pg/g fat in the control. The percentages of TEQ due to the measured congeners in exposed groups were 9-10.3% for PCDDs, 20.5-26.9% for PCDFs, 19.2-23.1% for coplanar and 43.6-47.2% for mono-ortho PCBs. In control, the percentage of TEQ was 11.6, 26.7, 24.1, and 37.5%. PCBs, predominantly PCB156, followed by PCB126 contributed 60 to 70% of the total TEQ value. Positive correlation of the PCDD/PCDF/PCB blood levels with age and with consumption of locally produced eggs was found.     

Modelling the Competitive Sorption Process of Multiple Solutes During their Transport in Porous Media

A general mathematical model to solve the advection–dispersion transport equation for multiple solutes was developed, where the dual porosity mobile–immobile mass transfer, the two-site non-equilibrium model and first-order transformation reactions were included. The two-site model was expressed with an equilibrium sorption term and a kinetic term. One of three kinetic models could be used: the non-linear, the bilinear and the pore diffusion model. The traditional Freundlich or Langmuir isotherms were employed to simulate no-interaction between the solutes, but with the extended Freundlich or extended Langmuir isotherms, a competitive sorption could be simulated. The transport equation was solved with the Moving Concentration Slope method. The mathematical model was tested and further simplified by using real data from soil column experiments, with 1,2-cis-dichloroethene and trichloroethene as model contaminants and silica gel and real soil samples as porous medium.     

Characteristics of Muscular Load in Computer Data Entry Workers Assessed by EMG and Postural Angles

The goal of this study was to characterize the muscular load in computer data entry workers. Electromyography (EMG) parameters of trapezius muscle and postural angles of head, arm, and back were chosen as indicators of musculoskeletal load. The examination was done according to the methods and protocol of international MEPS studies (the “Musculoskeletal, Visual, and Psychosocial Load in VDT [Video Display Terminal] Operators in Optimized Environment” international program). The musculoskeletal load during routine VDT data entry work performed by a group of 36 women was assessed on the basis of 1-hr physiometer recordings. Results show that the musculoskeletal load associated with data entry is relatively high compared to other VDT operators’ tasks described in the literature. An analysis of the measured parameters shows that most of the time women worked with a muscular load higher than optimal. It is postulated that the main reason for the heavy musculoskeletal load was improper posture compelled by unergonomic spatial configuration of work stands.     

Toxicity of ozonated animal manure to the house fly, Musca domestica

Swine manure slurries were ozonated at a dosage of 1 g/L and tested for their toxicity to the house fly (Musca domestica). The observed toxicity of ozonated swine manure was consistent and independent of origin of the swine manure. A dose (dilution) response curve was performed. A 50% dilution in the ozonated swine manure slurry resulted in 90% reduction in toxicity. Neither the synthetic nor ozonated synthetic swine manure, both of which contained higher concentrations of formaldehyde and three other unidentified carbonyl compounds than the ozonated swine manure, were toxic to the flies. Ozonated swine manure slurry was centrifuged and passed through a 0.45-microm filter. The liquid phase was as toxic as the unfiltered slurry; as such, the toxicant appears to be present in liquid phase. Neither ammonia, hydrogen sulfide, formaldehyde, nor other simple aldehydes appeared to be the toxic agent. The toxic agent appears to be a polar chemical compound and is concentrated in the urine. Several possible compounds have been identified. The toxicity of untreated and ozonated manure slurries from different livestock was compared. Six animal manure slurries (beef and dairy cattle, horse, poultry, sheep, and swine) were ozonated (dosage of 1 g/L) and tested for toxicity to the house fly. Ozonated dairy cattle manure slurry showed 78% mortality after 72 h, whereas ozonated swine manure slurry achieved a 100% mortality rate in 48 h. Neither the unozonated dairy nor swine manure slurries, nor any of the other raw or ozonated manure slurries, were toxic to the flies.