The non-calorie sweetener sucralose - sucrose containing three chlorine atoms - is intensively sweet and has become a popular substitute for sugar. Its widespread use, exceptional stability in combination with high water solubility have thus resulted in contamination of recipient waters. Earlier studies on sucralose in aquatic organisms indicate low bioaccumulation potential and negligible acute/chronic toxicity, but the close structural resemblance with sucrose in combination with the importance of sugar in nature, warrants a more detailed ecotoxicological assessment. The aim of this investigation was therefore to study behavioural and physiological effects of sucralose in. Our results show that both physiological and locomotion behavior were affected by exposure to sucralose. In Daphnia magna, the behavioural response was manifested as altered swimming height and increased swimming speed, whereas in gammarids the time to reach food and shelter was prolonged. Regardless if these behavioural responses were initiated via traditional toxic mechanisms or stimulatory effects, they should be considered as a warning, since exposed organisms may diverge from normal behaviour, which ultimately can have ecological consequences.

A continuous supply of water with defined stable concentrations of hydrophobic chemicals is a requirement in a range of laboratory tests such as the OECD 305 protocol for determining the bioconcentration factor in fish. Satisfying this requirement continues to be a challenge, particularly for hydrophobic chemicals. Here we present a novel solution based on equilibrium passive dosing. It employs a commercially available unit consisting of ∼16 000 polydimethylsiloxane (PDMS) tubes connected to two manifolds. The chemicals are loaded into the unit by repeatedly perfusing it with a methanol solution of the substances that is progressively diluted with water. Thereafter the unit is perfused with water and the chemicals partition from the unit into the water. The system was tested with nine chemicals with log KOW ranging from 4.1 to 6.3. The aqueous concentrations generated were shown to be largely independent of the water flow rate, and the unit to unit reproducibility was within a factor of ∼2. In continuous flow experiments the aqueous concentrations of most of the study chemicals remained constant over 8 d. A model was assembled that allows prediction of the operating characteristics of the system from the log KOW or PDMS/water partition coefficient of the chemical. The system is a simple, safe, predictable and flexible tool that generates stable aqueous concentrations of hydrophobic chemicals.

n September/October 2009, six ground-based Fourier Transform Spectrometers (FTS) of the Total Carbon Column Observation Network (TCCON) in Europe were calibrated with aircraft in-situ measurements for the first time. The campaign was part of the Infrastructure for Measurement of the European Carbon Cycle (IMECC) project. During this campaign aircraft in-situ profiles of CO2, CH4, CO and H2O (from continuous measurements) as well as N2O, H2, and SF6 (from flasks) were taken close to the FTS sites. The aircraft data had a vertical coverage ranging from approximately 300 to 13 000 m, corresponding to ~80% of the total atmospheric column seen by the FTS. This study summarizes the calibration results for CH4. Using similar methods, the resulting calibration factor of 0.978 ± 0.002 (±1 σ) from the IMECC campaign agreed very well with the results that Wunch et al. (2010) had derived for TCCON instruments in North America, Australia, New Zealand, and Japan. By adding the data of the previous calibration of Wunch et al. (2010), the uncertainty of the calibration factor could be reduced by a factor of three. A careful analysis of the calibration method used by Wunch et al. (2010) revealed that the incomplete vertical coverage of the aircraft profiles can lead to a bias in the calibration factor. This bias can be compensated with a new iterative approach that we developed. Using this improved method, we derived a significantly lower calibration factor of 0.974 ± 0.002 (±1 σ). This corresponds to a correction of all TCCON CH4 measurements by roughly −7 ppb.

Inhalable airborne particles have inverse health effects. In railways, mechanical brakes, the wheel–rail contact, current collectors, ballast, sleepers, and masonry structures yield particulate matter. Field tests examined a Swedish track using a train instrumented with particle measurement devices, brake pad temperature sensors, and speed and brake sensors. The main objective of this field test was to study the characteristics of particles generated from disc brakes on a running train with an on-board measuring set-up. Two airborne particle sampling points were designated, one near a pad–rotor disc brake contact and a second under the frame, not near a mechanical brake or the wheel–rail contact; the numbers and size distributions of the particles detected were registered and evaluated under various conditions (e.g. activating/deactivating electrical brakes or negotiating curves). During braking, three speed/temperature-dependent particle peaks were identified in the fine region, representing particles 280, 350, and 600 nm in diameter. In the coarse region, a peak was discerned for particles 3–6 µm in diameter. Effects of brake pad temperature on particle size distribution were also investigated. Results indicate that the 280-nm peak increased with increasing temperature, and that electrical braking significantly reduced airborne particle numbers. Field emission scanning electron microscope images captured particles sizing down to 50 nm. The inductively coupled plasma mass spectrometry results indicated that Fe, Cu, Zn, Al, Ca, and Mg were the main elements constituting the particles.

The comparative accumulation of C4eC15 perfluorinated sulfonates (PFSAs) and carboxylates (PFCAs), and several precursors (e.g., perfluorooctane sulfonamide, N-methyl-FOSA, and fluorotelomer unsaturated acids and alcohols) was examined in tissues (liver, brain, muscle, and adipose), plasma/red blood cells (RBCs) and whole egg clutches (yolk and albumen) of female herring gulls collected in 2010 from Chantry Island, Lake Huron of the Laurentian Great Lakes. Highest mean PPFSA concentrations were in yolk, followed by adipose, liver, plasma, muscle, RBCs, and brain. Highest mean PPFCA concentrations were in yolk, followed by brain, plasma, liver, RBC, adipose and muscle. PFOS accounted for >88% of PPFSA in all samples; the liver, plasma/RBCs, muscle and adipose PFCA patterns were dominated by C8eC11 PFCAs, whereas C10eC15 PFCAs in brain and yolk. Among PFSAs and PFCAs there is tissue-specific accumulation, which could be due to a number of pharmacokinetic processes.

Med hjälp av samtidiga mätningarna av koncentrationerna av PAH och NOx på Hornsgatan och på taket på Mariapolikliniken på Södermalm i Stockholm, beräknades bidraget till halterna från vägtrafiken på Hornsgatan. De beräknade emissionsfaktorerna har jämförts med emissionsfaktorer för avgasemissioner från bensin och dieselfordon enligt mätningar i avgaslaboratorier. De uppmätta emissionerna är generellt lägre än de som uppskattas för avgaserna. Detta indikerar att däckslitaget inte är speciellt betydelsefullt för halterna, men de rapporterade avgasemissionerna kan vara för höga vilket gör att det inte går att helt utesluta att däckslitage också kan vara betydelsefullt. En källreceptormodell användes för att uppskatta bidragen till halterna på Södermalm från vedeldning, bensin- och dieselavgaser, däckslitage samt bakgrunden (intransporten) baserat på de uppmätta halterna på taket på Mariapolikliniken samt de olika profilerna för vedeldning, bensin och diesel som presenteras ovan (däcksbidraget antogs vara försumbart). De beräknade halterna stämmer mycket väl med de uppmätta halterna. För de flesta PAH:erna, med undantag för dibensopyrenerna, ger vedeldning störst bidrag med mellan ca: 40 % och 60 %. Därefter kommer dieselavgaser. För dibensopyrenerna är variationen stor mellan vilka källor som bidrar mest. För DB(a,l)P dominerar dieselavgaser. Om man summerar B(a)P och dibensopyrenerna dominerar vedledning på grund av att B(a)P ger störst bidrag och domineras av vedeldning. Men om dibensopyrenernas halter multipliceras med TEF-värden blir fördelningen av de relativa bidragen helt annorlunda; diesel, bakgrunden och vedeldningen ger 37 %, 32 %, respektive 24 %’s bidrag till summan av de viktade värdena för B(a)P och dibensopyrenerna. Den totala befolkningens i Storstockholm exponering för olika källor beräknades med hjälp av en spridningsmodell. Beräkningarna innefattar 1.4 miljoner invånare och tar hänsyn till den geografiska variationen i halterna och var personerna bor. Medelexponeringen för Storstockholms befolkning är 45 pg/m3 för B(a)P, vilket är betydligt lägre än det svenska miljömålet på 100 pg/m3 (0.1 ng/m3). För dibensopyrenerna är befolkningsexponeringen 0.73, 13, 3.4 och 0.93 pg/m3 för DB(a,l)P, DB(a,e)P, DB(a,i)P respektive DB(a,h)P. För dessa ämnen finns inga miljömål eller gränsvärden att jämföra med. Beräkningarna indikerar att intransporten ger det största bidraget. Av de lokala källorna står vedeldning och vägtrafik för de viktigaste bidragen. Cancerrisken ökar signifikant då hänsyn tas till dibensopyrenerna. Med enbart B(a)P blir medelexponeringen 45 pg/m3. För summan B(a)P och de fyra dibensopyrenerna blir exponeringshalten 173 pg/m3, motsvarande en ökad cancerrisk med nästan en faktor 4. Bidraget till exponeringen från olika källor är ungefär detsamma med enbart B(a)P jämfört med att man tar hänsyn till TEF-viktade bidrag från dibensopyrenerna. Detta innebär att de viktigaste lokala källorna som bör åtgärdas för att minska cancerrisken blir desamma med respektive utan hänsyn till bidraget från dibensopyrenerna.