Voluntary corporate environmental initiatives and shareholder wealth

Researchers debate whether environmental investments reduce firm value or actually improve financial performance. We provide some compelling evidence on shareholder wealth effects of membership in voluntary environmental programs (VEPs). Companies announcing membership in EPA's Climate Leaders, a program targeting reductions in greenhouse gas emissions, experience significantly negative abnormal stock returns. The price decline is larger in firms with poor corporate governance structures, and for high market-to-book (i.e., high growth) firms. However, firms joining Ceres, a program involving more general environmental commitments, have insignificant announcement returns, as do portfolios of industry rivals. Overall, corporate commitments to reduce greenhouse gas emissions appear to conflict with firm value maximization. This has important implications for policies that rely on voluntary initiatives to address climate change. Further, we find that firms facing climate-related shareholder resolutions or firms with weak corporate governance standards – giving managers the discretion to make such voluntary environmentally responsible investment decisions – are more likely to join Climate Leaders; decisions that may result in lower firm value.     

Non-steady response of BOD biosensor for the determination of biochemical oxygen demand in wastewater

A biochemical oxygen demand (BOD) biosensor for effective and expeditious BOD(7) estimations was constructed and the non-steady phase of the output signal was extensively studied. The modelling approach introduced allows response curve reconstruction and a curve fitting procedure of good quality, resulting in parameters indicating the relationship between response and organic substrate concentration and stability properties of the BOD biosensor. Also, the immobilization matrixes of different thicknesses were characterized to determine their suitability for bio-sensing measurements in non-stationary conditions, as well as for the determination of the mechanical durability of the BOD biosensor in time. The non-steady response of the experimental output of the BOD biosensor was fitted according to the developed model that enables to determine the stability of the biosensor output and dependency on biodegradable organic substrate concentration. The calibration range of the studied BOD biosensor in OECD synthetic wastewater was 15-110 mg O(2) L(-1). Repeatability tests showed relative standard deviation (RSD) values of 2.8% and 5.8% for the parameter τ(d), characterizing the transient output of the amperometric oxygen sensor in time, and τ(s), describing the dependency of the transient response of the BOD biosensor on organic substrate concentration, respectively. BOD biosensor experiments for the evaluation of the biochemical oxygen demand of easily degradable and refractory municipal wastewater showed good concurrence with traditional BOD(7) analysis.     

Synergistic effects of metal nanoparticles and a phenolic uncoupler using microdroplet-based two-dimensional approach

A droplet-based microfluidic technique for testing multiple reagent concentrations is presented. We used this experimental approach to study combined effects of gold (AuNP) and silver nanoparticles (AgNP) with the phenolic uncoupler 2,4-dinitrophenol (DNP) with respect to the growth of Escherichia coli. In order to evaluate the toxicity of binary mixtures, we first encapsulated the E. coli cells and particle mixtures inside the microdroplets using PEEK (polyetherketone) modules. Two-dimensional concentration spaces with about 500 well separated droplets were addressed. We subsequently analyzed the cell growth, the viability and the autofluorescence intensity (metabolic activity) of the bacteria with a micro-flow-through fluorometer and photometer. Dose-dependent synergistic effects were found for the binary mixture of AgNPs and DNP, which indicated a stronger interaction in the mixture than it was expected from effect summation. For the binary mixture of DNP and AuNPs in non-toxic concentrations, we found only weak synergistic effects at low DNP concentrations. Furthermore, the non-toxic tested AuNPs causes effect summation in the binary mixture with the phenolic uncoupler. In general, we demonstrated the efficiency of a droplet-based microfluidic system for fast high-throughput screenings of binary and multiple mixtures. This work also confirmed the relevance of highly resolved droplet-based assays for the miniaturization of ecotoxicological aquatic test systems.     

A ventilation cooling shirt worn during office work in a hot climate: cool or not?

The aim of the study was to identify whether a ventilation cooling shirt was effective in reducing heat strain in a hot climate. Eight female volunteers were exposed to heat (38?°C, 45% relative humidity) for 2?h with simulated office work. In the first hour they were in normal summer clothes (total thermal insulation 0.8?clo); in the second hour a ventilation cooling shirt was worn on top. After the shirt was introduced for 1?h, the skin temperatures at the scapula and the chest were significantly reduced (p?<?0.05). The mean skin and core temperatures were not reduced. The subjects felt cooler and more comfortable by wearing the shirt, but the cooling effect was most conspicuous only during the initial 10?min. The cooling efficiency of the ventilation shirt was not very effective under the low physical activity in this hot climate.     

Air-sea gas exchange of HCHs and PCBs and enantiomers of alpha-HCH in the Kattegat Sea region

Concentrations and air-water gas exchange of polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs) were determined in nine paired air and water samples. The samples were collected monthly in the Kattegat Sea between December 1998 and November 1999. Average fugacity and flux values indicated that PCBs were oversaturated in the water, while HCHs were net deposited. Variations were large over the year, especially during spring and summer. Air parcel back trajectories suggested that air concentrations over the Kattegat Sea are largely dependent of air mass origin. Seasonal trends were detected for airborne HCHs and for PCBs in water. The air and water enantiomeric compositions of alpha-HCH indicated that a larger portion of alpha-HCH in air originated from the underlying water during summer than during winter.     

Spatial variations and correlations in the distribution of PCDDs, PCDFs and related compounds in sediments from the river Rhine — Western Europe

PCDDs, PCDFs and some related aromatic compounds were determined isomer specifically in sediments from the river Rhine and its tributaries, in order to study sources and environmental fate of these compounds. Additionally, waste water effluents from industries that unintentionally might coproduce PCDDs or PCDFs were analyzed. In all sediments and in some waste water effluents these compounds could be detected. Variations of the isomeric patterns of the PCDFs enabled a distinct industrial area, that was associated with PCB contamination to be identified. The contamination of sediments and organisms from the Dutch river Rhine delta with these compounds mainly could be attributed to the transboundary pollution of the river Rhine.     

Partition coefficients of organic chemicals derived from reversed phase thin layer chromatography: Evaluation of methods and application on phosphate esters,polychlorinated paraffins and some PCB-substitutes

The application of reversed phase high performance thin layer chromatography has been evaluated for determination of octanol-water partition coefficients (P_oct) of organic chemicals. Best correlations between log P_oct and R_M-values were obtained on a C₁₈-bonded stationary phase using acetone-water or acetonitrile-water mixtures as eluting solvent. The latter mixture is preferred in work with high pressure liquid chromatography. A number of aryl and alkyl/aryl phosphate esters, polychlorinated paraffins and chemicals suggested as PCB-substitutes were chromatographed and the corresponding log P_oct-values calculated. Values for the phosphate esters corresponded reasonably well with previously reported data while data for other, often more complex compound mixtures (eg PCB-substitutes), need further evaluation. The use of the chromatographic system for screening purposes in work on environmentally significant data of possible organic pollutants is discussed.     

True trisomy 15 mosaicism,detected by amniocentesis at 12 weeks of gestation and fetal echocardiography

A case of mosaicism of trisomy 15, with two-thirds of the cells trisomic, was detected at 12 weeks of gestation in amniotic fluid cell cultures obtained with the filtration technique. Ultrasound examination at 13 weeks showed a nodule protruding into the amniotic cavity which was speculated to be remnants of a co-twin, causing the trisomic cell line. At 20 weeks of gestation, a malformation scan (level III) was normal, but supplementary fetal echocardiography revealed a severe cardiac defect (mitral atresia and a ventricular septal defect). Fetal lymphocytes obtained by cordocentesis showed trisomy 15 mosaicism, but only in 5 per cent of the mitoses. After termination, the same percentage of trisomy 15 mosaicism was found in cells from skin and tendon as in the original early amniocentesis. No sign of earlier twinning was found in the placenta or membranes. We conclude that mosaicism in early amniotic fluid obtained by the filter technique in this case reflected the true karyotype accurately and that supplementary echocardiography added significantly to the interpretation of the clinical implications.     

Alpha-fetoprotein and acetylcholinesterase activity in first-and early second-trimester amniotic fluid

Normal ranges of amniotic fluid alpha-fetoprotein (AFP) and acetylcholinesterase activity (AChE) are described for gestational weeks 11–14 using rocket gel immunoelectrophoresis for AFP quantitation and a monoclonal antibody (4F19) enzyme antigen immunoassay for AChE activity measurement. The normal ranges were established by the examination of 281 amniotic fluid samples from 281 normal pregnancies. AFP was found to increase from a median level of 14.0 MIU/1 at 11 weeks to a maximum at 13 weeks (median=18.0 MIU/l) (P<0.05), thereafter falling (not significant). No AChE test result exceeded 4.8 nkat/l. In addition, AFP and AChE values for three cases of fetal malformation, identified by the biochemical analyses of amniotic fluid, are given. These cases included two fetuses with a neural tube defect and one fetus with an abdominal wall defect. Amniocentesis was performed at 10, 11, and 14 weeks, respectively. The AFP and AChE values were all high.