 Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles Therefore, it is necessary to understand the distribution between the phases According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format The compilation contains 17 350 values of Henry's law constants for 4632 species, collected from 689 references It is also available at http://wwwhenrys-laworg 

/pdf/compilation-of-henry-s-law-constants-version-4-0-for-water-58il9q0ogv.pdf

Compilation of Henry's law constants (version 4.0) for water as solvent

Atmospheric mercury—An overview

Over the past decade it has become apparent that the atmosphere is a significant pathway for the transport of many natural and pollutant materials from the continents to the ocean. The atmospheric input of many of these species can have an impact (either positive or negative) on biological processes in the sea and on marine chemical cycling. For example, there is now evidence that the atmosphere may be an important transport path for such essential nutrients as iron and nitrogen in some regions. In this report we assess current data in this area, develop global scale estimates of the atmospheric fluxes of trace elements, mineral aerosol, nitrogen species, and synthetic organic compounds to the ocean; and compare the atmospheric input rates of these substances to their input via rivers. Trace elements considered were Pb, Cd, Zn, Cu, Ni, As, Hg, Sn, Al, Fe, Si, and P. Oxidized and reduced forms of nitrogen were considered, including nitrate and ammonium ions and the gaseous species NO, NO2, HNO3, and NH3. Synthetic organic compounds considered included polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), DDTs, chlordane, dieldrin, and hexachlorobenzenes (HCBs). Making this assessment was difficult because there are very few actual measurements of deposition rates of these substances to the ocean. However, there are considerably more data on the atmospheric concentrations of these species in aerosol and gaseous form. Mean concentration data for 10° × 10° ocean areas were determined from the available concentration data or from extrapolation of these data into other regions. These concentration distributions were then combined with appropriate exchange coefficients and precipitation fields to obtain the global wet and dry deposition fluxes. Careful consideration was given to atmospheric transport processes as well as to removal mechanisms and the physical and physicochemical properties of aerosols and gases. Only annual values were calculated. On a global scale atmospheric inputs are generally equal to or greater than riverine inputs, and for most species atmospheric input to the ocean is significantly greater in the northern hemisphere than in the southern hemisphere. For dissolved trace metals in seawater, global atmospheric input dominates riverine input for Pb, Cd, and Zn, and the two transport paths are roughly equal for Cu, Ni, As, and Fe. Fluxes and basin-wide deposition of trace metals are generally a factor of 5-10 higher in the North Atlantic and North Pacific regions than in the South Atlantic and South Pacific. Global input of oxidized and reduced nitrogen species are roughly equal to each other, although the major fraction of oxidized nitrogen enters the ocean in the northern hemisphere, primarily as a result of pollution sources. Reduced nitrogen species are much more uniformly distributed, suggesting that the ocean itself may be a significant source. The global atmospheric input of such synthetic organic species as HCH,PCBs, DDT, and HCB completely dominates their input via rivers.

The atmospheric input of trace species to the world ocean

Persistent organic pollutants (POPs): state of the science.

Control strategies for these contaminants will require a better understanding of how they move around the globe.

Peer reviewed: tracking the distribution of persistent organic pollutants.

Plant biomass plays a significant role in the global environmental partitioning phenomena and plants are good indicators of tropospheric contamination levels by chlorinated hydrocarbons. In the present research 300 samples of plants were collected in 265 areas distributed worldwide and analyzed for HCB (hexachlorobenzene), {alpha}-HCH (hexachlorocyclohexane), {gamma}-HCH, p,p{prime}-DDT,o,p{prime}-DDT, and p,p{prime}-DDE (degradation product of DDT). Global HCB distribution is strongly dependent on the temperature, the HCB being present mainly in samples from cold areas. The sum of DDTs show higher concentrations in samples from topical areas, while the sum of HCHs is higher in the plants from the Northern Hemisphere. These results are discussed, taking into account the role of physicochemical properties in determining the global distribution as well as the air age of the contamination.

Role of plant biomass in the global environmental partitioning of chlorinated hydrocarbons

Chlorinated hydrocarbons in lichen and moss samples from the Antarctic Peninsula

The concentration of 12 semivolatile organochlorine compounds-SOC-[hexachlorobenzene, [alpha]-hexachlorocyclohexane, [gamma]-hexachlorocyclohexane, 4,4[prime]-DDT, 4,4[prime]-DDE, and 7 polychlorinated biphenyl congeners PCB 28 (2,4,4[prime]-Cl[sub 3]B), PCB 52 (2,2[prime],5,5[prime]-Cl[sub 4]B), PCB 101 (2,2[prime],4,5,5[prime]-Cl[sub 5]B), PCB 118 (2,3[prime],4,4[prime],5-Cl[sub 5]B), PCB 138 (2,2[prime],3,4,4[prime],5-Cl[sub 6]B), PCB 153 (2,2[prime],4,4[prime],5,5[prime]-Cl[sub 6]B), PCB 180 (2,2[prime],3,4,4[prime],5,5[prime]-Cl[sub 7]B)]-has been measured in moss, lichen, and foliage samples collected near Ulm (south Germany). These values are compared with air measurements reported for the same region. The bioconcentration factors vegetation/air (BCF) obtained in this way are compared with those reported from both environmental and laboratory studies. Some of the latter are used to calculate mean concentrations of SOC in air which are in agreement with direct air measurements. 63 refs., 4 figs., 5 tabs.

Correlation between C-6/C-14 chlorinated hydrocarbons levels in the vegetation and in the boundary layer of the troposphere

Organochlorine pesticide and PCB residues in plant foliage: (Mangifera indica) from West Africa

The case study develops and applies a systematic approach to the precautionary pre-selection of xenobiotic organic chemicals with respect to large-scale environmental problems. It defines a kind of guardrail for chemical innovation that could be helpful in avoiding costly errors and it demonstrates how precaution acts as a kind of assurance against ignorance. The study starts from scenarios for unmanageable situations and identifies necessary conditions for their occurrence that then are related to a set of carefully defined proxy measures, such as characteristic isotropic spatial range. The proxy measures related to a particular scenario are combined in a screening filter. The threshold levels for the combined proxy measures are fixed through recourse to historical and present-day chemicals so as to filter out as many as possible of the now regulated environmental chemicals and to let pass the economically important compounds of no large-scale environmental concern. The totality of filters, with each filter corresponding to a scenario, provides the filter series to be used for precautionary screening. With respect to the classical environmental chemicals, precautionary screening completely reproduces the historical outcome of decades in a shortcut without jeopardizing compounds of top economic importance. E1. Precaution and Chemical Risk Assessment The appraisal of potential adverse effects of new and existing chemicals is one of the most tedious and costly burdens of innovation in the chemical industry. It requires considerable efforts without, however, as yet having brought about a fundamental reduction of chemical overall stress in man and the environment. In order to improve the situation, both industry and regulating agencies have called for an overhaul of the relevant procedures. The most recent efforts are the Swedish Committee’s report on New Guidelines on Chemicals Policy (Swedish Committee 2000) and the EU’s White Paper on Strategy for a Future Chemicals Policy (Commission of the European Communities 2001). In many of these documents, the precautionary principle has been cited as an instrument for a more adequate procedure. However, there is still no general agreement on how to put the precautionary principle into practice. Within PrecauPri the regulation of chemicals serves as a test case for the design of appropriate procedures in the application of precautionary reasoning in industrial innovation. In particular, the PrecauPri case study adds some specific types of precautionary pre-selection * See also appendices G 1-7. ** Corresponding author address: ETH Zurich, Postfach 150, 8093 Zurich, Switzerland; E-mail: muellerherold@umnw.ethz.ch; phone: +41-1-632-4403; fax: +41-1-633-1136.

Marco Morosini

Papers

Role of plant biomass in the global environmental partitioning of chlorinated hydrocarbons

Chlorinated hydrocarbons in lichen and moss samples from the Antarctic Peninsula

Correlation between C-6/C-14 chlorinated hydrocarbons levels in the vegetation and in the boundary layer of the troposphere

Organochlorine pesticide and PCB residues in plant foliage: (Mangifera indica) from West Africa

The Application of the Precautionary Principle in the European Union