Comparison of methods for the extraction and determination of polychlorinated biphenyls in shiphull antifoulings

A method is presented for the determination of PCBs in chlorinated rubber antifoulings. In ten different brands, no PCB concentrations above 0.5 mg kg^?1 were found.     

Verteilung und Abnahme von bodennahem Ozon in st?dtischen und l?ndlichen Regionen

Zusammenfassung  Eine Zusammenstellung der Ozon-Me?werte der Luftme?stationnetze in Hessen und NRW ergab für die Jahresmittelwerte von 1990–1998 im Durchschnitt eine schwache Abnahme der Ozonkonzentrationen. Dabei lagen die Jahresmittelwerte der Ozonkonzentrationen über Waldstationen doppelt so hoch wie über Stadtstationen. Die Ozonkonzentrationen verhalten sich im regionalen Vergleich umgekehrt proportional zur Verkehrsdichte. In der Zahl der überschreitungen der gesetzlich festgelegten Grenzwerte von ≥180 μg Ozon/m³ pro Jahr lagen die Waldstationen mit dem 2–3 fachen Wert über den Stadtstationen. Lediglich die j?hrlichen Maximalwerte der stündlich gemessenen Ozonwerte n?hern sich einander. Die hohen Ozonwerte über den Waldstationen stehen im Zusammenhang mit den niedrigen Konzentrationen von NOx. Nachts reduziert sich das Ozon über den Waldstationen durch Rückreaktion mit vergleichsweise geringen Konzentrationen von NO nur bis ca. 50%, w?hrend der Ozongehalt über Stadtstationen bis nahe Null absinkt. Dieser Vorgang über den Stadtstationen wird auch durch Photolyse des in hohen Konzentrationen vorliegenden NO₂ und die dadurch erfolgende erh?hte Bildung von Ozon w?hrend des Tages nicht wieder kompensiert. Für die hier dargestellten Ergebnisse gibt es prinzipiell keine Unterschiede zwischen den Ozonverh?ltnissen in Hessen und NRW.      

Mechanism and kinetic model for the decolorization of the azo dye Reactive Black 5 by hydrogen peroxide and UV radiation

A kinetic model for the decolorization of C.I. Reactive Black 5 by the combination of hydrogen peroxide and UV radiation was developed based on experimental results and known chemical and photochemical reactions. The observed kinetic reaction coefficient was determined and correlated as a function of hydrogen peroxide concentration and UV intensity. The validity of the rate expression was tested experimentally in a parameterization study. The decolorization rate follows pseudo-first order kinetics with respect to dye concentration. The rate increases linearly with UV intensity and nonlinearly with increasing hydrogen peroxide concentration, going from a linear relationship at low H(2)O(2) concentrations to a maximum as hydrogen peroxide concentration continues to increase. The decolorization rate expression derived from the proposed reaction mechanism was reconciled with that used for correlating the experimental data.     

Lowered birth weight among infants born to women with a high intake of fish contaminated with persistent organochlorine compounds

In Sweden fatty fish from the Baltic Sea (at the Swedish east coast) constitute the main exposure route for persistent organochlorine compounds (POC). The present study assessed reproductive outcomes among fishermen's sisters from the Swedish east coast, who were shown to had had a relatively high consumption of contaminated fish in early life. For relevant comparison, we used a similar cohort from the Swedish west coast, where the contamination of fish is considerable less. The east coast cohort women had an increased risk of having an infant with low birth weight (LBW; <2500 g) as compared with the west coast cohort women (odds ratio (OR) 1.6. 95% confidence interval 1.1-2.3). The results strengthen the hypothesized association between exposure to POC during childhood and adolescence and an increased risk for LBW.     

Shift in ectomycorrhizal community composition in Scots pine (Pinus sylvestris L.) seedling roots as a response to nickel deposition and removal of lichen cover

Scots pine seedlings were exposed to wet-deposited nickel (Ni) and removal of lichen cover in a dry heath Scots pine forest. Ni deposition affected the colonization of roots by indigenous ectomycorrhizal fungi in contrasting ways in intact and skimmed quadrats. Highest frequencies of tubercle morphotypes of ectomycorrhiza were found in quadrats exposed to 100 mg m⁻² year⁻¹ Ni in lichen covered treatment, while in skimmed quadrats these peaked after the treatment with 10 mg Ni m⁻² year⁻¹. Removal of the lichen layer increased the value of diversity index (H′) of ectomycorrhizal fungal community, probably due to the increase in the evenness of the morphotype distribution. Lichen removal seemed also to improve the condition of the short roots, as the frequencies of poor and senescent short roots were decreased by the removal.     

Determination of toxaphenes in fish and marine mammals

An analytical method for the determination of toxaphene in biological materials using gas chromatography with an electron capture detector (GC-ECD) has been established and validated for three single congeners (chlorinated bornanes (CHB) 26, 50 and 62). The analytical method was based on a method for determination of PCB, DDT and other chlorinated pesticides. To include toxaphene congeners an extra step, adsorption chromatography on silica columns, was introduced to separate the pesticides from PCB. The recovery of CHB-26, 50 and 62 were 97+/-11%, 94+/-10% and 99+/-12%, respectively. Samples from cod, ringed seal and polar bear from the Norwegian arctic environment have been analysed. The levels of CHB-26 and 50 found were 13-55 ng/g fat in cod, 1.3-7.7 ng/g fat in ringed seal and 0.4-119 ng/g fat in polar bear. The levels of CHB-62 were 2.0-13, 0.8-3.4, 0.2-11 ng/g fat in cod, ringed seal and polar bear, respectively.     

An improved automatic recording apparatus for determining the filtration rate of Mytilus edulis as a function of size and algal concentration

An automatic recording apparatus for measuring the filtration rate in suspension-feeding bivalves is described. The concentration of algae in the experimental medium is kept constant throughout each experiment by addition of Phaeodactylum tricornutum from a chemostat. Within the range of body size 5.7 to 283 mg (W=dry weight of tissues), the filtration rate (F=ml min^-1) at 15°C in Mytilus edulis L. follows the allometric equation F=0.85 W ^0.72. Within the concentrations 0.18 to 0.70 mg algal dry weight l^-1, the filtration rate in mussels of 132 mg dry flesh weight ranges from 33.1 to 41.0 ml min^-1. At 0.18 mg algal dry weight l^-1 the mussels filter continuously for 20 h, with a high constant rate that presumably represents the water transport capacity under optimal laboratory conditions.