Surfactant solubilization of hydrophobic compounds in soil and water

The soil/water partition coefficient (K_d) of hexachlorobenzene (HCB) ranged from 220 1/kg to 1800 1/kg for eight soils having a wide range of physico-chemical properties. K_d normalised to soil organic carbon (K_oc) was found to be 28000 ± 4800 1/kg. Anionic surfactant dodecylsulphate (DS) present at concentrations above the critical micellar concentration (CMC) caused reductions in the apparent soil/water partition coefficient (K_d ^*) in the range of 3–26 times for most soils and up to 36–91 times for sandy soils. Below CMC, at environmentally relevant surfactant concentrations, K_d ^* was reduced by a factor of 1–13. For clay and calcareous soils significant adsorption/complexation/precipitation of DS occurred. At the lowest DS concentration this produced a two-fold increase in K_d ^*. At increasing DS concentrations this effect was shielded by the solubihzing effect from DS. Monomer (K_mn) and micellar (K_mc) surfactant/water partition coefficients for HCB were determined to be, 980 ± 190 1/kg and 21000 ± 1600 1/kg, respectively.     

Chemical and biological characterization of emissions from a cereal straw burning furnace

Emissions from a cereal straw through-burning furnace have been characterized by chemical analysis and the Ames $\text{Salmonella/microsome}$ assay. The emissions of polycyclic aromatic hydrocarbons (PAH) were considerable, from 24 to 64 mg per kilo dry fuel. Most of the mutagenic activity was found in the extracts of the particles, while the condensate fractions and the XAD-2 extracts showed much lower mutagenic responses.     

A comparative study on the biosorption characteristics of some yeasts for Remazol Blue reactive dye

Biosorption capacities and rates of different kinds of dried yeasts (Saccharomyces cerevisiae, Schizosaccharomyces pombe, Kluyveromyces marxianus, Candida sp., C. tropicalis, C. lipolytica, C. utilis, C. quilliermendii and C. membranaefaciens) for Remazol Blue reactive dye from aqueous solutions were compared under laboratory conditions as a function of initial pH and initial dye concentration. Optimum initial biosorption pH was determined as 2 for all the yeasts. All the yeast species showed comparable and very high dye sorption at 100 mg/l initial dye concentration. The equilibrium sorption capacity of the biomass increased with increasing initial dye concentration up to 400 mg/l for Candida sp. C. lipolytica and C. tropicalis; up to 300 mg/l for C. quilliermendii and C. utilis and up to 200 mg/l for S. cerevisiae, S. pombe, K. marxianus and C. membranaefaciens while the adsorption yield of dye showed the opposite trend for all the yeasts. Among the nine yeast species, C. lipolytica exhibited the highest dye uptake capacity (Q(0) = 250 mg/g). Both the Freundlich and Langmuir adsorption models were found suitable for describing the biosorption of the dye by all the Candida yeasts (except C. membranaefaciens). The results indicated that the dye uptake process followed the pseudo-second-order kinetics for each dye-yeast system.     

Environmental risk assessment of human pharmaceuticals in Denmark after normal therapeutic use

An environmental risk assessment is presented for the 25 most used pharmaceuticals in the primary health sector in Denmark. Predicted environmental concentrations (PECs) for the aquatic environment were calculated using conservative assumptions and all PECs exceeded 1 ng/l. Measured concentrations were in general within a factor of 2-5 of PECs and ranged from approximately 0.5 ng/l to 3 micrograms/l for nine of the pharmaceuticals reported in literature. The calculation of predicted no-effect concentration (PNEC) based on aquatic ecotoxicity data was possible for six of the pharmaceuticals. PEC/PNEC ratio exceeded one for ibuprofen, acetylsalicylic acid, and paracetamol. For estrogens the PEC/PNEC ratio approached one when non-standard test was used. The ratio was below one for estrogens (standard test), diazepam and digoxin. For the terrestrial compartment, toxicity data were not available, and no assessment was carried out. Comparisons of predicted concentrations of furosemide, ibuprofen, oxytetracycline and ciprofloxacin in sludge based on either preliminary experimental sludge-water partition coefficients (Kd), octanol-water coefficients (Kow) or acid-base constants (pKa) revealed large variations.     

A comparison of chemical MSW compositional data between China and Denmark

Chemical waste compositions are important for municipal solid waste management, as they determine the pollution potentials from different waste strategies. A representative dataset for chemical characteristics of individual waste fractions is frequently required to assess chemical waste composition, but it is usually reported in developed countries and not in developing countries. In this study, a dataset for Chinese waste was established through careful data screening and assessment, named as CN dataset. Meanwhile, a dataset for Danish waste (DK dataset) was also summarized based on previous studies. In order to quantitatively evaluate the reliabilities of CN and DK datasets, the chemical waste compositions in four Chinese cities were estimated by utilizing both of them, respectively. It is indicated that the usage of CN datasets led to significantly lower discrepancies from the actual values based on laboratory analysis in most cases. Within the datasets, the moisture contents of food waste, paper, textiles, and plastics, the carbon content of food waste, as well as the oxygen content of plastics would induce significant divergences, which should be paid special attention when gathering the information. In addition, the fractional waste compositions in China showed similar features with other developing countries but differ significantly with developed countries. Thus the above-mentioned conclusions could also be true in other developing countries.     

Lost benefits and carbon uptake by protection of Indian plantations

There is a range of problems in assessing how protection of a specific forest to Reduce Emissions from Deforestation and forest Degradation (REDD+) affect global emissions of greenhouse gases. This paper shows how knowledge and information about the biophysical characteristics of forests can be combined with theories of forest management and economic behaviour to derive the impacts on global emissions of REDD+. A modelling experiment from India, where 10% of the forest plantations in eight different regions are protected, shows that the biophysical characteristics of forests are decisive for the global impacts on emissions. In regions with slow-growing forests, agents in the non-protected forests are able to increase their output significantly to fill the demand from the protected forests. This opportunity is strictly limited in regions with fast-growing forests. Therefore, prices increase far more in regions with fast-growing forests than in slow-growing forests. Over time, the markets for Indian forestry products contribute to reduce the resulting price differences across regions. When the carbon uptake from protected forests approaches zero, the leakage of emissions to other Indian forests is between 20 and 40%. Only a small part of this is international leakage. Combining different models also helps to identify knowledge gaps, and to distinguish gaps that potentially may be filled with data and new knowledge, and gaps due to different angling of modelling biophysical processes and modelling of economic behaviour.     

Prevalence and concentrations of drugs in older suspected drugged drivers

Objective: Older drivers are somewhat more likely to be involved in car crashes than middle-aged drivers but less likely to be involved than younger drivers. This study aimed to assess the extent of drug use in older suspected drunk and drugged drivers, with respect to which drugs were detected and at which concentrations.

Methods: Blood samples from older suspected drunk and drugged drivers taken between February 1, 2012, and May 22, 2013, were identified from the database at the Norwegian Institute of Public Health and were retrospectively analyzed for a broad repertoire of drugs relevant for impairment. The prevalence of different drugs among the suspected drunk and drugged drivers was studied. Regarding drug concentrations, the findings in older drivers (>65 years) were compared to a reference group of apprehended drivers aged 20–40 years.

Results: Four hundred and ten older suspected drunk and drugged drivers were included. Any drug (including ethanol) was detected in 92% of blood samples, and ethanol was detected in 81%. Benzodiazepines were found in 15% of the older drivers and z-hypnotics (zopiclone or zolpidem) were detected in 13%. The most frequent single legal drugs found in blood samples taken from older impaired drivers were zopiclone (9.8%) and diazepam (9.3%). Regarding drug combinations, older drivers used a mean number of 1.4 drugs, and 20% of ethanol-positive cases showed at least one other drug. High drug concentrations of clonazepam and diazepam were more frequently seen in the younger group.

Conclusions: This study showed that drugs were detected in the vast majority of older drivers suspected for drunk or drugged driving. Ethanol was the most frequent drug detected, followed by zopiclone and diazepam. Older drivers combine drugs to a lesser degree than younger drivers, but their combination of ethanol and other drugs represents a considerable traffic risk. Lower concentrations of benzodiazepines are seen in older compared to younger drivers.