Photolysis of polycyclic aromatic hydrocarbons adsorbed on spruce [Picea abies (L) Karst] needles under sunlight irradiation

Photolysis of polycyclic aromatic hydrocarbons (PAHs) sorbed on surfaces of spruce [Picea abies (L.) Karst.] needles under sunlight irradiation was investigated. PAHs were produced by combustion of polyvinyl chloride (PVC), wood, high-density polyethylene (HDPE), and styrene in a stove. The factors of sunlight irradiation on the surfaces of spruce needles were taken into consideration when investigating the kinetic parameters. The photolysis of the 18 PAHs under study follows first-order kinetics. The photolysis half-lives range from 15 h for dibenzo(a,h)anthracene to 75 h for phenanthrene. Photolysis of some PAHs on surfaces of spruce needles may play an important role on the fate of PAHs in the environment.     

Fate of 14C-bisphenol A in soils

Bisphenol A (BPA; 2,2-(4,4(')-dihydroxydiphenyl)propane) is predominantly used as an intermediate in the production of polycarbonate plastics and epoxy resins. Traces of BPA released into the environment can reach the soil via application of sewage sludge from wastewater treatment systems that receive wastewaters containing BPA, or from leachate from uncontrolled landfills. The biodegradability of BPA has been previously investigated in several studies designed to simulate surface waters and biological wastewater treatment systems. However, there is little information available about the fate of BPA in soil. Therefore, laboratory soil degradation and batch adsorption studies were conducted with 14C-BPA and four soils according to international guidelines. The soils represented a broad range of physico-chemical properties. An important result of the degradation study was that, independent of the soil type, 14C-BPA was rapidly dissipated and not detectable in soil extracts following 3 days of incubation. Based on this result, a dissipation half-life of less than 3 days was estimated. The major route of dissipation of 14C-BPA in soil was the formation of bound residues that could not be recovered by exhaustive Soxhlet extraction. 14C-BPA was also shown to be transiently converted to up to five metabolites, but within 3 days, neither 14C-BPA nor 14C-metabolites were detectable in the soils. After 120 days incubation, significant amounts (up to 20% of the radioactivity applied) of the parent compound were recovered as 14CO(2). Soil adsorption experiments indicated that the distribution coefficients (K(oc)) were between 636 and 931, classifying BPA as having low mobility for all tested soils. From the results of this study, it was concluded that if BPA reaches the soil compartment, it is not expected to be stable, mobile, or bioavailable.     

Prediction of pesticide volatilization with PELMO 3.31

In the current EU risk assessment for pesticide registration, the European Community requires prediction of the concentration of each pesticide in air. A number of mathematical models are used to assess the fate of pesticides in groundwater, surface water and soil. PELMO 3.20 calculates the volatilization fluxes from bare soil and was improved in the new version PELMO 3.31 to include the effect of temperature and sorption in dry soil. The objective of this study was to evaluate the new version of PELMO 3.31 in predicting the pesticide volatilization under field conditions. Procymidone, malathion, and ethoprophos were the test compounds in two different seasons (autumn and winter). Comparing simulation results obtained with PELMO 3.31, after calibration, with the previous version PELMO 3.20 shows that the estimated volatilization results seems improved for malathion, similar or slightly overestimating in the warmer season for ethoprophos, and similar or slightly underestimating in the colder season for procymidone. The new release of PELMO allows a more accurate estimation of pesticides volatilization from soil as function of meteorological factors, especially for medium or low volatility pesticides. Some difficulties remain, such as the determination of the active air layer and the sorption increment with the soil drying.     

Generic scenario for the impact of cooling lubricants into the hydrosphere

According to directive 93/67/EEC of the European Commission, this paper deals with the generic exposition evaluation of the environmental concentration of cooling Lubricant chemicals from the metal working industry into the hydrosphere. After considering the relevant life-cycle steps and the selection of a representative point source for the 'reasonable worst case', the emission per day Elocal(water) is determined. It leads to the predicted environmental concentration (PEClocal(water)) for the local stage in the compartment water. In order to gain the PEClocal(water) for an example--a corrosion inhibitor as additive in a cooling lubricant--, the relevant emission paths and the corresponding representative point source are described for the reasonable worst case. For non-water-miscible cooling lubricants, none of the operations in the life cycle leads to a release into the compartment water. To evaluate the hazard potential for cooling lubricant chemicals, the complete risk assessment has to be done. Also, the assessment has to be done for all high production volume chemicals, new substances and existing hazard chemicals. This means that even industrial categories like chemicals used in the textile industry or biocides and others have to be evaluated.     

An apparatus for automatic counting and controlling density of pelagic food particles in cultures of marine organisms

A particle control system is described for automatic collection of samples, and determination and control of the density of particles in marine suspensions. Densities are determined electronically, allowing colourless microorganisms to be detected. Computer operated magnetic valves allow multiple cultures to be sampled, measured and fed, using compressed air and a vacuum pump. Conditions and variables, determined in the software, enable flexible adjustment to specific culture conditions. The system was applied in the cultivation of the copepod Acartia clausi Giesbrecht, using a 95 m orifice with a particle size range of 8 to 32 m. Some results are given of monitoring and controlling the density of heterotrophic flagellates as food in the copepod cultures at different conditions of temperature and autotrophic food.     

Climate change mitigation strategies in the forest sector: biophysical impacts and economic implications in British Columbia,Canada

Managing forests to increase carbon sequestration or reduce carbon emissions and using wood products and bioenergy to store carbon and substitute for other emission-intensive products and fossil fuel energy have been considered effective ways to tackle climate change in many countries and regions. The objective of this study is to examine the climate change mitigation potential of the forest sector by developing and assessing potential mitigation strategies and portfolios with various goals in British Columbia (BC), Canada. From a systems perspective, mitigation potentials of five individual strategies and their combinations were examined with regionally differentiated implementations of changes. We also calculated cost curves for the strategies and explored socio-economic impacts using an input-output model. Our results showed a wide range of mitigation potentials and that both the magnitude and the timing of mitigation varied across strategies. The greatest mitigation potential was achieved by improving the harvest utilization, shifting the commodity mix to longer-lived wood products, and using harvest residues for bioenergy. The highest cumulative mitigation of 421 MtCO₂e for BC was estimated when employing the strategy portfolio that maximized domestic mitigation during 2017–2050, and this would contribute 35% of BC’s greenhouse gas emission reduction target by 2050 at less than $100/tCO₂e and provide additional socio-economic benefits. This case study demonstrated the application of an integrated systems approach that tracks carbon stock changes and emissions in forest ecosystems, harvested wood products (HWPs), and the avoidance of emissions through the use of HWPs and is therefore applicable to other countries and regions.