Sulfur polymer solidification/stabilization of elemental mercury waste

Elemental mercury, contaminated with radionuclides, presents a waste disposal problem throughout the Department of Energy complex. In this paper we describe a new process to immobilize elemental mercury wastes, including those contaminated with radionuclides, in a form that is non-dispersible, will meet EPA leaching criteria, and has low mercury vapor pressure. In this stabilization and solidification process, elemental mercury is combined with an excess of powdered sulfur polymer cement (SPC) and sulfide additives in a mixing vessel and heated to approximately 40 degrees C for several hours, until all of the mercury is converted into mercuric sulfide (HgS). Additional SPC is then added and the temperature of the mixture raised to 135 degrees C, resulting in a molten liquid which is poured into a mold where it cools and solidifies. The final treated waste was characterized by powder X-ray diffraction and found to be a mixture of the hexagonal and orthorhombic forms of mercuric sulfide. The Toxicity Characteristic Leaching Procedure was used to assess mercury releases, which for the optimized process averaged 25.8 microg/l, with some samples being well below the new EPA Universal Treatment Standard of 25 microg/l. Longer term leach tests were also conducted, indicating that the leaching process was dominated by diffusion. Values for the effective diffusion coefficient averaged 7.6x10(-18) cm2/s. Concentrations of mercury vapor from treated waste in equilibrium static headspace tests averaged 0.6 mg/m3.     

Measuring reactive nitrogen emissions from point sources using visible spectroscopy from aircraft

Accurate measurements of nitrogen dioxide (NO2), a key trace gas in the formation and destruction of tropospheric ozone, are important in studies of urban pollution. Nitrogen dioxide column abundances were measured during the Texas Air Quality Study 2000 using visible absorption spectroscopy from an aircraft. The method allows for quantification of the integrated total number of nitrogen dioxide molecules in the polluted atmosphere and is hence a useful tool for measuring plumes of this key trace gas. Further, we show how such remote-sensing observations can be used to obtain information on the fluxes of nitrogen dioxide into the atmosphere with unique flexibility in terms of aircraft altitude, and the height and extent of mixing of the boundary layer. Observations of nitrogen dioxide plumes downwind of power plants were used to estimate the flux of nitrogen oxide emitted from several power plants in the Houston and Dallas metropolitan areas and in North Carolina. Measurements taken over the city of Houston were also employed to infer the total flux from the city as a whole.     

The accumulation of person-environment congruences and well-being

The impact of the additivity of three aspects of person-environment congruence — vocational, avocational and skill utilization — to well-being was assessed by four measures: occupational satisfaction, work satisfaction, somatic complaints and anxiety. Subjects were 74 female teachers. Findings showed: (a) the three congruence aspects were not interrelated; (b) all congruence aspects were correlated with all well-being measures in the expected direction; and (c) combinations of the three congruence aspects had an additive effect: the higher the number of congruence aspects the higher the well-being. The implications of congruence additivity to stress research and to vocational counselling was discussed.     

Atmospheric mercury at mediterranean coastal stations

Mercury in air has been measured at five coastal Mediterranean sites, involving measurements in Spain, France, Italy, Slovenia and Israel. Four two-weeks long measurements campaigns were performed at the five sites. The measurements were carried out during autumn 2003 and winter, spring and summer 2004. Total gaseous mercury/elemental gaseous mercury, particulate mercury and divalent gaseous mercury were measured in parallel at the five sites. The activities constituted a subtask of the EU funded MERCYMS research project, which also included Mediterranean Sea cruises where both mercury in air and water were measured. The result from an evaluation of all the coastal air data is presented. Mercury concentrations from the different sites are compared with similar data obtained in northern Europe and elsewhere. The result shows that the background concentration of mercury in Mediterranean coastal air is lower than earlier anticipated. Background concentrations of TGM, RGM and TPM corresponded to 1.75–1.80 ng m⁻³, 1–13 and 3–23 pg m⁻³, respectively. The measurements also showed that the mercury concentration occasionally can be very high in some areas due to local anthropogenic emissions. It is proposed that diurnal variation in RGM concentrations observed during situation with nocturnal inversion merely is an effect of meteorology rather than due to local photochemistry.     

Work-load,perceived control and psychological distress in Type A/B industrial workers

The effects of work-load (WL) and perceived control (PC) on the psychological well-being of Type A and Type B industrial workers were studied using Karasek's Job Demands-Control model (1979). Subjects were 3562 male workers from 21 factories in Israel. Compared to Type B, Type As showed higher stress symptoms (irritability, somatic complaints, anxiety) but also higher job satisfaction. Contrary to our hypotheses, Type As were not more stressed under conditions of low load or low PC. These findings run counter to intuitive deductions based on the ambitious, hard-driving characteristics and control needs attributed to Type As. However there is some indication that a combination of low load and low PC (passive jobs) can be stressful for Type As, as indicated by high irritability scores. In addition, Type As were adversely affected by high load while Type Bs were not. Moreover, Type Bs reported high job satisfaction. Tests of Karasek's model revealed significant main effect for WL and PC on all dependent variables, but no interaction effects. Finally, incorporating Type A/B into the model indicated that the hypothesized high strain jobs combining high load and low PC proved to be stressful for Type As only.