Water quality of rivers depends often on the degree of urbanization and the population density in the catchment. This study shows results of a monitoring campaign of total concentration of polycyclic aromatic hydrocarbons (PAHs) and suspended particles in water samples in adjacent catchments in Southern Germany with similar geology and climate but different degrees of urbanization. Defined linear relationships between total concentrations of PAHs in water and the amount of suspended solids were obtained indicating predominance of particle-facilitated transport. The slopes of these regressions correspond to the average contamination of suspended particles (Csus) and thus comprise a very robust measure of sediment pollution in a river. For the first time, we can show that Csus is distinct in the different catchments and correlates to the degree of urbanization represented by the number of inhabitants per total flux of suspended particles.

Mass transfer processes of pollutants from non-aqueous phase liquids (NAPL) may control groundwater pollution at abandoned industrial sites. We studied release kinetics of polycyclic aromatic hydrocarbons (PAHs) from fresh and aged tar phases using a dialysis tubing technique. Time for equilibration ranged from several days to more than three years. For fresh tar materials the release seems to be limited by retarded pore diffusion, while for two of three aged tars diffusion limited release influenced by dissolved organic matter (DOM) was assumed. The equilibration process was driven by solubilization thermodynamics expressed by Raoult's law. Yet, solubility enhancement was observed potentially due to the presence of organic mobile sorbents. The results show that the release of PAHs from tar phases is generally rate limited and partitioning according to Raoult's law is the driving mechanism of the exchanges process.

The accumulation of 134Cs and 85Sr within different parts of spring oilseed rape and spring wheat plants was investigated, with a particular focus on transfer to seeds after artificial wet deposition at different growth stages during a two-year field trial. In general, the accumulation of radionuclides in plant parts increased when deposition was closer to harvest. The seed of spring oilseed rape had lower concentrations of 85Sr than spring wheat grain. The plants accumulated more 134Cs than 85Sr. We conclude that radionuclides can be transferred into human food chain at all growing stages, especially at the later stages. The variation in transfer factors during the investigation, and in comparison to previous results, implies the estimation of the risk for possible transfer of radionuclides to seeds in the event of future fallout during a growing season is still subject to considerable uncertainty.

High PBDE concentrations have been detected in the eggs of the sexually dimorphic Eurasian sparrowhawk (Accipiter nisus) but little is known about contamination levels in adult birds and how this may vary with age and sex. We characterised liver PBDE concentrations in 59 sparrowhawks that had died in central Britain between 1998 and 2009 and determined how concentrations varied with sex, age, body condition and breeding status. Five BDE congeners (99 > 153 > 47 > 100 > 154) predominated and ΣPBDE concentrations were 10–15 fold and 2–3 fold higher in starved than non-starved adult and juvenile sparrowhawks, respectively. This was likely due to a combination of remobilisation of residues from other tissues and liver wastage. Liver ΣPBDE concentrations did not vary with sex but were greater in adults than juveniles, suggestive of accumulation with age. Overall, liver ΣPBDE concentrations ranged from 43.4 to 68,040 ng/g lipid weight, amongst the highest concentrations reported in birds anywhere.

Sediments collected from an urban creek in China exhibited high acute toxicity to Hyalella azteca with 81.3% of sediments being toxic. A toxic unit (TU) estimation demonstrated that the pyrethroid, cypermethrin, was the major contributor to toxicity. The traditional TU approach, however, overestimated the toxicity. Reduced bioavailability of sediment-associated cypermethrin due to sequestration explained the overestimation. Additionally, antagonism among multiple contaminants and species susceptibility to various contaminants also contributed to the unexpectedly low toxicity to H. azteca. Bioavailable TUs derived from the bioavailability-based approaches, Tenax extraction and matrix-solid phase microextraction (matrix-SPME), showed better correlations with the noted toxicity compared to traditional TUs. As the first successful attempt to use matrix-SPME for estimating toxicity caused by emerging insecticides in field sediment, the present study found freely dissolved cypermethrin concentrations significantly improved the prediction of sediment toxicity to H. azteca compared to organic carbon normalized and Tenax extractable concentrations.

Dispersal of 137Cs from the nuclear submarine wrecks Komsomolets and K-159, which are resting on the seabed in the Norwegian and Barents Seas, respectively, is simulated using realistic rates and hypothetical scenarios. Furthermore, spatiotemporal 137Cs concentrations in Northeast Arctic cod and capelin are estimated based on survey data. The results indicate that neither continuous leakages nor pulse discharges will cause concentrations of 137Cs in cod muscle or whole body capelin exceeding the intervention level of 600 Bq/kg fw. Continuous leakages from Komsomolets and K-159 and pulse discharges from Komsomolets induced negligible activity concentrations in cod and capelin. A pulse discharge of 100% of the 137Cs-inventory of K-159 will, however, result in concentrations in muscle of cod of above 100 times the present levels in the eastern Barents Sea. Within three years after the release, 137Cs levels above 20 Bq/kg fw in cod are no longer occurring in the Barents Sea.

Tetracycline (TC), a common antibiotic, can behave as an efficient ligand with cations, but the effect of its interaction with heavy metal cations on the mobility of both species in soils has not been well evaluated. In this study, the complexation affinities of TC with Cd (II), Cu (II) and Pb (II) were examined using potentiometric titration and spectroscopic methods. The cosorption behavior of TC and metal ions onto three selected Chinese soils was evaluated using batch adsorption experiments. The presence of metal cations promoted TC adsorption through an ion bridging effect in the order Cu (II) > Pb (II) > Cd (II), which is in accordance with their complexation ability with TC. The addition of TC affects metal adsorption differently depending on the solution pH and metal type. Therefore, it is necessary to consider the complexation ability of TC and divalent metal cations when evaluating their mobility in soils.

A pot experiment was conducted to investigate the solubility and redox species of antimony (Sb) in a relocated shooting range soil and its uptake by Lolium perenne L. and Holcus lanatus L. under different water regimes. After 1-week waterlogging, the total Sb concentration in soil solution decreased from ∼110 μg L−1 to <20 μg L−1, and slowly increased over the following 4 weeks, with the dissolution of Fe and Mn (hydr)oxides. In this process, half of the Sb in soil solution was reduced to Sb(III), which greatly affected the plant uptake of Sb. Waterlogging increased shoot Sb concentrations of L. perenne by ∼10 fold but decreased uptake in H. lanatus by 80%. Results indicate that Sb might primarily be taken up as Sb(III) by L. perenne and as Sb(V) by H. lanatus. Temporary waterlogging of soil may increase the risk of trace elements entering the food chain.

We investigated the impacts of effluent discharge from small flow-through fish farms on stream water characteristics, the benthic invertebrate community, whole-system nitrate uptake, and ecosystem metabolism of three tropical headwater streams in southeastern Brazil. Effluents were moderately, i.e. up to 20-fold enriched in particulate organic matter (POM) and inorganic nutrients in comparison to stream water at reference sites. Due to high dilution with stream water, effluent discharge resulted in up to 2.0-fold increases in stream water POM and up to 1.8-fold increases in inorganic nutrients only. Moderate impacts on the benthic invertebrate community were detected at one stream only. There was no consistent pattern of effluent impact on whole-stream nitrate uptake. Ecosystem metabolism, however, was clearly affected by effluent discharge. Stream reaches impacted by effluents exhibited significantly increased community respiration and primary productivity, stressing the importance of ecologically sound best management practices for small fish farms in the tropics.

Many important environmental contaminants are hydrophobic organic contaminants (HOCs), which include PCBs, PAHs, PBDEs, DDT and other chlorinated insecticides, among others. Owing to their strong hydrophobicity, HOCs have their final destination in soil or sediment, where their ecotoxicological effects are closely regulated by sorption and thus bioavailability. The last two decades have seen a dramatic increase in research efforts in developing and applying partitioning based methods and biomimetic extractions for measuring HOC bioavailability. However, the many variations of both analytical methods and associated measurement endpoints are often a source of confusion for users. In this review, we distinguish the most commonly used analytical approaches based on their measurement objectives, and illustrate their practical operational steps, strengths and limitations using simple flowcharts. This review may serve as guidance for new users on the selection and use of established methods, and a reference for experienced investigators to identify potential topics for further research.