The deposition of atmospheric tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, alpha-HCH, gamma-HCH, DDT, DDE and the PCB congeners 52, 101, 138, 153 and 180 to spruce needles (Picea abies) was estimated for a period of 9 months. Accumulation in spruce as a result of dry gaseous deposition, particle bound deposition and wet deposition was calculated on the basis of the corresponding deposition rates and the compounds' concentrations in the different atmospheric compartments. The comparison of the calculated values with the concentrations of the compounds measured in 9-month-old spruce needles showed that for many compounds each deposition pathway could explain a large part of the concentrations found in the needles.

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.

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.

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been monitored in air and deposition at four UK urban sites (London, Cardiff, Manchester and Stevenage) since the beginning of 1991; data from the first 2 years are presented here. Median Sigma 2,3,7,8-substituted PCDD/F concentrations in air were 3.2, 4.0, 3.5 and 2.6 pg/cubic metre respectively for London, Cardiff, Manchester and Stevenage. Median Sigma 2,3,7,8-substituted PCDD/F deposition fluxes were 1.5 ng/m** (2)/day in London, 1.4 ng/m** (2)/day in Cardiff and Manchester and 0.79 ng/m** (2)/day in Stevenage. Seasonal variations in the PCDD/F concentrations were observed at all sites for both air and deposition, with concentrations/fluxes generally elevated during the winter.

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.

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.

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.

This comprehensive, interdisciplinary reference explains the basic physical, hydrological, chemical, and biochemical processes and mechanisms governing contaminants in the subsurface vadose zone - an often overlooked problem that is of major worldwide societal concern. Additionally, this important resource provides helpful case studies representing state-of-the-art techniques and contains never-before-published research findings on, and recommendations for solving, groundwater contamination. | Covering a wide spectrum of groundwater contamination sources and their chemical, transport, and release characteristics, Groundwater Contamination and Control considers the preventive as well as corrective approaches in combatting the threat of irreversible groundwater pollution ... explores the challenges faced in remediating and rehabilitating polluted soils and aquifers ... analyzes the legislative aspects that arise when monitoring landfills, spills, and industrial sites ... reviews the U.S. Environmental Protection Agency's Groundwater Disinfection Rule ... describes the in situ process of on-site remediation ... discusses the political and legal issues involved in cases where aquifers are shared between people or countries ... previews future trends in on-site analysis and monitoring methods ... and much more. | Illustrated with nearly 450 figures, tables, and equations and containing more than 1700 literature citations to facilitate further in-depth study, Groundwater Contamination and Control is essential reading for pollution control, environmental, chemical, industrial, sanitary, and civil engineers; chemists; hydrologists; ecologists; agronomists; environmental scientists; waste management consultants; environmental regulators and government policymakers; and upper-level undergraduate and graduate students in these disciplines.