Interpretation of the greenhouse data from the ice cores are sometimes based on rejection of analytical results, and often on assumptions disregarding gas fractionation processes. At present, our understanding of these processes in ice sheets is rather poor. There is a need for experimental studies which would provide the essential physical and chemical parameters needed. Before such studies are carried out, conclusions on low pre-industrial atmospheric levels of greenhouse gases cannot be accepted when deduced from ice core data. High contamination of the inner parts of the ice cores with lead and other metals by the drilling procedure is compelling evidence that the cores do not fulfil the absolutely essential, closed system criterion. Thus, they are not suitable for reconstruction of the composition of pre-industrial and ancient atmosphere.

The separation and determination of sub-micromol per litre levels of six environmentally significant As compounds was accomplished by means of high performance liquid chromatography (HPLC) combined online with inductively coupled plasma mass spectrometry (ICP-MS). The species of interest (arsenite and arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine) were quantified in fish and mussel extracts after separation on a Dionex AS7 column equipped with an on-guard AG7 column using a bicarbonate buffer as the mobile phase in a gradient mode. The species thus eluted were directly forwarded to the ICP-MS detector. The detection power of the overall system allows each As form to be determined at concentrations as low a 0.0013 - 0.0027 micromol per litre.

The ocean plays a central role in the global carbon cycle being by far the largest active reservoir. Atmospheric CO2 level depends on the CO2 concentration in the ocean surface layer, which is relatively low compared to mean oceanic values due to biological and physical carbon pumps. Although the ocean may take up much of the carbon released by the increased burning of fossil fuels, this capacity is limited because of the chemical buffering and a mismatch in time scales (oceanic mixing is much slower than anthropogenic perturbations).

According to present understanding, persistent superlipophilic chemicals - such as octachlorodibenzo-p-dioxin, octachlorodibenzofuran, Mirex etc - with log K(OW) over 6 and cross sections over 9.5 A, bioconcentrate in aquatic organisms only little from ambient water. The most convincing argument against it is that in bioconcentration experiments with superlipophilic chemicals amounts applied exceeded water solubility by several orders of magnitude. This paper describes various methods for determining bioconcentration factors (BCF) of superlipophilic compounds. As exemplified with octachlorodibenzo-p-dioxin, BCF values evaluated by these methods match well with those calculated by QSARs for fish and mussels based on log K(OW) and water solubility. As expected, these BCF values exceed previous values by several orders of magnitude. For BCF evaluation of superlipophilic chemicals in aquatic organisms it is recommended: (i) flow-through systems, kinetic method (OECD guideline No. 305 E), (ii) ambient concentrations below water solubility, (iii) during the uptake and especially during the elimination phase no toxic effects of the test organisms should occur.

The treatment of hazardous sites in Baden-Wuerttemberg is based on three legal documents: the state waste disposal act (LAbfG, 1990), the assessment committee directive (Kommissions VO, 1990), and the guide values directive (UM and SM B-W, 1993). The guide values directive was commonly issued by the Ministry of Labor, Health and Social Affairs and the Ministry of the Environment of the state of Baden-Wuerttemberg (UM and SM B-W, 1993) and contains a three-level hierarchy of numerical criteria and rules which serve as both screening levels during the investigation and as remediation objectives. The decision for the appropriate level of remediation is based on feasibility and environmental balance considerations. The levels are ordered as follows: - 1. (Background-Values) On principle, all remediations have to be based first on background levels. In the case of lack of feasibility or negative environmental balance for level-1 objectives use-specific requirements are considered next. - 2. (Assessment-Values for Worst Case Exposure Conditions) The generic requirements underlying level 2 afford appropriate protection for humans regarding the most sensitive uses of the environment. At least four resources are considered on this level: Groundwater as such and its use, the health of humans on contaminated sites, and soil with respect to growth and quality of plants. Barriers against migration of the contaminants, the effect of dilution, and abandonment of certain uses, etc., are not taken into consideration on level 2. - 3. (Site-Specific Requirements) Lack of feasibility or a negative environmental balance of level-2 objectives lead to consideration of site-specific circumstances which may alleviate the requirements.

Volatilization from treated areas is a major source of pesticide residues in air, fog, and rain. This may lead to long-range transport of pesticide residues to remote areas. Up to now most information on pesticide volatilization has come from laboratory experiments under controlled conditions. A new system has been designed and developed to measure the volatile losses of (l4)C-labelled chemicals after application; the method compares with agricultural practice of treating soils or plants grown in lysimeters. Sensitive analytical methods guarantee a distinction between residues of unchanged pesticide, its metabolites or (14)CO2 as a mineralization product released into the air.

Reductions in the apparent soil-water partition coefficients (K(d)* ) for 28 polychlorinated biphenyls (PCBs) caused by the surfactant sodium dodecylsulphate (SDS) in the aqueous phase were studied. Above the critical micelle concentration (CMC) of the surfactant, K(d)* was reduced by 2-3 orders of magnitude, but even far below CMC at environmentally relevant surfacant concentrations significant reductions in Kd3 were observed. The plot of the soil-water partition coefficient (K(d)) divided by K(d)* versus the concentration of SDS allowed for the calculation of monomer (K(mn)(oc)) and micellar (K(mc)(oc)) surfactant-water parrition coefficients normalized to organic carbon for each PCB congener. K(mn)(oc) values were comparable with published values for the partition of PCBs between natural dissolved organic matter and lake water. K(mc)(oc) values were up to 30 times higher than K(mn)(oc) values and comparable with published octanol-water distribution coefficients. The findings of the present study underline the potential of surfactants at concentrations below their CMC to mobilize otherwise strongly bound hydrophobic compounds in soil-water systems.