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).

Although polychlorinated biphenyls (PCBs) are no longer manufactured, they are still entering the environment. In some compartments of the environment, PCB concentrations are a serious concern. This is especially true in compartments which accumulate PCBs, and in food items consumed by humans and wildlife. Also, there are situations in which management decisions require rapid, sensitive, accurate measurements, which can be made in real time under field conditions. Methods to use an enzyme-linked immunosorbent assay (ELISA) for PCBs were developed and applied to sediments and fish muscle homogenates collected from the Great Lakes. The extraction methods developed can be applied in the field with non-hazardous solvents, in the absence of sophisticated laboratory equipment. The method detection limit for PCBs in dimethyl sulfoxide (DMSO) extracts of sediment was 0.9 mg/kg. For PCBs in isopropanol extracts of fish tissue, the method detection limit was 0.6 mg/kg. The resolution of the ELISA was 0.83 mg/kg at 1.1 mg/kg and 1.6 mg/kg at 1.7 mg/kg, for sediment and fish tissue, respectively.

Rainwater and surface water from four sites in Germany (Bavaria and Lower Saxony) were analyzed for atrazine by enzyme immunoassay from June 1990 until October 1992. The limit of quantification of the immunoassay was 0.02 microgram per litre with a middle of the test at 0.2 microgram per litre. About 60% of the samples contained measurable amounts of atrazine. Seasonal trends were observed, with the highest concentration in the summer months of up to 4 microgram per litre for rainwater and up to 15 microgram per litre for surface waters. The highest concentrations were found in agricultural areas, while in the investigated national parks up to 0.56 microgram per litre could be detected in rain warer. This points to long-range atmospheric transport from agricultural areas to pristine national parks. Samples from forest stands usually showed higher atrazine concentrations than samples from open fields. Deposition rates of 10 - 50 microgram per m** (2) per year were observed in the national parks and 10 - 180 microgram per m** (2) per year at the agricultural sites. Comparison of results obtained by enzyme immunoassay and GC/MS showed a good correlation of r = 0.95.

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.

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.