Showing papers in "Environmental Science and Pollution Research in 1994"

TOXIC EQUIVALENCY FACTORS FOR DIOXIN-LIKE PCBs

Abstract: Several PCDDs and PCDFs, as well as a few (dioxin-like) PCBs have been shown to exert a number of common toxic responses similar to those observed for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). These include dermal toxicity, immunotoxicity, reproductive deficits, teratogenicity, endocrine toxicity, and carcinogenicity/tumour promotion. There is strong evidence suggesting a common mechanism of action of 2,3,7,8-TCDD and related compounds, based on a binding of these compounds to a specific receptor (the Ahreceptor). Due to the fact that dioxin-like compounds normally exist in environmental and biological samples as complex mixtures of congeners, the concept of toxic equivalents (TE Qs) has been introduced to simplify risk assessment and regulatory control. In applying this concept, relative toxicities of dioxin-like compounds in relation to 2,3,7,8-TCDD (i.e. toxic equivalency factors, TEFs) are determined based on in vitro and in vivo studies. This approach is based on the evidence that there is a common, receptor-mediated mechanism of action for these compounds.

Mass spectral and GC data of drugs, poisons, pesticides, pollutants and their metabolites (Parts 1, 2, 3)

Abstract: These three volumes of gas chromatography (GC) and mass spectral (MS) data are an essential reference work for any professional working in the fields of clinical & forensic toxicology or analytical toxicology. The organization of the vast quantity of information facilitates the identification of unknowns by mass spectra, Kovats retention index, molecular weight, or even by compound class. The authors are to be congratulated for their attention to detail and their understanding of how to best use GC-MS data for the identification of drugs, poisons, and their metabolites. Whether a novice or experienced professional, those in the clinical & forensic toxicology or analytical toxicology fields will find these volumes essential additions to their library.

Haloacetic acids, phytotoxic secondary air pollutants.

Abstract: Haloacetic acids are atmospheric oxidation products of airborne C2-halocarbons which are important solvents and propellants. Levels of trichloroacetate (TCA) in conifer needles from mountain ranges in Germany (Black Forest, Erzgebirge) and from two sites in Finland are compared; TCA is present in conifer needles at concentrations up to 0.7 μmol/kg, MCA up to 0.2 μmol/kg. At the Finnish sites, TCA-concentrations and branch degeneration symptoms of Scots pine are correlated. Monochloroacetate (MCA) has been determined in needle samples from Southern Germany in concentrations exceeding its phytotoxicity threshold towards photoautotrophic organisms. Data on atmospheric chloroacetate levels in Germany are also given; ambient air levels of chloroacetic acids range from about 2 pmol/m3 (TCA) to 390 pmol/m3 (MCA). TCA and dichloroacetic acid (DCA) arise from atmospheric oxidation of airborne C2-chlorocarbons, while the source of MCA is not yet known; several tentative pathways are suggested.

Environmental hazard : Assessment of chemicals and products.

Abstract: Part II: Persistence and Degradability of Organic Chemicals The criteria “Persistence” and “Degradability” are defined and explained, starting from the “functional” definition of the environment. In this definition, theenvironment is the counterpart of thetechnosphere, which consists of all processes controlled by man. A substance is persistent if there are no sinks (degradation processes). It is shown that persistence is the central and most important criterium of environmental hazard assessment of organic chemicals. It follows that all substances released into the environment should be degradable, preferentially into small inorganic molecules (mineralization). As examples for persistent substances, the polychlorinated biphenyls (PCB), the chlorofluorohydrocarbons (CFC), bis (2-ethylhexyl) phthalate (DEHP), and 2,3,7,8-tetrachloro-dibenzo-dioxin (TCDD) are discussed. Finally, an attempt to quantify persistence is made.

Dietary and environmental estrogens and antiestrogens and their possible role in human disease.

Abstract: Recent reports have suggested that dietary and environmental estrogens such as organochlorine pollutants may play a role in the increased incidence of breast cancer in women and disorders of the male reproductive tract. For example, elevated levels of DDE and polychlorinated biphenyls (PCB) have been measured in women with breast cancer. However, it should also be noted that numerous environmental and dietary compounds have also been characterized as antiestrogenic and as inhibitors of mammary cancer cell growthin vitro and/orin vivo. Some of these compounds include 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds, polynuclear aromatic hydrocarbons (PAH), other naturally-occurring TCDD receptor agonists, retinoids, phorbol esters, terpenes, fatty acids, and polysaccharides. Thus, it is possible that dietary and environmental estrogens and antiestrogens may be contra-active, and these interactions must be considered in the overall risk assessment of the potential adverse human and environmental health impacts of these chemicals.

Uptake and metabolism of 2,4,6-trinitrotoluene in higher plants.

Abstract: The fate of the explosive 2,4,6-TNT in plants is of major interest. Therefore, a method was developed to analyse TNT and derivatives in plant tissue. The method was utilized to investigate the uptake and metabolism of TNT inMedicago sativa andAllium schoenoprasum grown in hydroponic cultures containing TNT levels of 0.1 to 10 mg/1. Detectable concentrations of nitrotoluenes were significantly higher inAllium schoenoprasum than inMedicago sativa. The uptake of TNT in plants was directly related to the initial TNT level. The principal nitroaromatic components in roots and shoots of both plant species were identified as 4-ADNT and 2-ADNT in equal amounts, with substantially less TNT.

Polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in urban air and deposition in the United Kingdom.

Abstract: 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 Σ2,3,7,8-substituted PCDD/F concentrations in air were 3.2, 4.0, 3.5 and 2.6 pg/m3 respectively for London, Cardiff, Manchester and Stevenage. Median Σ2,3,7,8-substituted PCDD/F deposition fluxes were 1.5 ng/m2/day in London, 1.4 ng/m2/day in Cardiff and Manchester and 0.79 ng/m2/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.

Toxicity testing of highly volatile chemicals with green algae : A new assay.

Abstract: A gas-tight system for toxicity testing of highly volatile chemicals with the green algaChlamydomonas reinhardtii was developed. The procedure permits maintenance of constant and defined concentrations of the tested compounds in the vessels. To ensure sufficient CO2-supply, new bipartite test vessels were used. These vessels allowed spatial separation of a HCO3-/CO 3 (2-) buffer used for CO2 supply and the alga culture to avoid growth inhibition due to ionic strength. Several volatile chlorinated hydrocarbons have been tested. Their EC10 values were several orders of magnitude lower than those obtained with open test systems.

Textiles as a source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in human skin and sewage sludge

Abstract: Polychlorinated dibenzo-p-dioxins and dibenzofurans were measured in low- to high-ppb concentrations in several pieces of new clothing from different manufacturers It was shown that these contaminants are transferred from textiles to human skin during wearing They were also present in shower water and were washed out of textiles during washing Extensive evidence was found indicating that contaminated textiles are a major source of chlorinated dioxins and furans in non-industrial sewage sludge, dry cleaning residues and house dust

A wind tunnel for measuring the gaseous losses of environmental chemicals from the soil/plant system under field-like conditions

Abstract: 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 of14C-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 or14CO2 as a mineralization product released into the air.

Observations on long-term air-soil exchange of organic contaminants.

Abstract: Evidence for long-term changes in the soil composition of selected organic compounds, brought about by exchanges with the atmosphere, is briefly reviewed. In the case of some compounds — such as benzo(a)pyrene and octachlorodibenzo-p-dioxin, soils may be significant long-term environmental sinks for atmospherically-derived material. In other cases — such as phenanthrene and some of the lighter PCBs, de-gassing or volatilisation from soil back to the air can occur under certain conditions. Hence the soil may act as a “short-term” sink, and a potential source to atmosphere. Indeed, for some ‘semi-volatile’ compounds used in large quantities in the past — such as PCBs, soil outgassing may actually be an extremely important source to contemporary air. Furthermore, soil outgassing from areas of former high use may provide an important driving mechanism for continued “global cycling” of a range of semi-volatile organochlorine compounds.

Sorption kinetics of chlorinated hydrophobic organic chemicals

Abstract: This is the second of a two-part series describing the sorption kinetics of hydrophobic organic chemicals. Part I “The Use of First-Order Kinetic Multi-Compartment Models” is published in issue 1 of this journal, pp. 21–28. Sorption kinetics of chlorinated benzenes from a natural lake sediment have been investigated in gas-purge desorption experiments. Biphasic desorption curves, with an initial “fast” part and a subsequent “slow” part, were found for all tested chlorobenzenes. From these results first-order sorption uptake and desorption rate constants were calculated with a two-sediment compartment model, which is presented in the first paper.

Simulation of pesticide runoff at Rosemaund Farm (UK) using the SoilFug model.

Abstract: A validation exercise of the SoilFug model using field runoff data from Rosemaund Farm (UK) is described. A comparison has been made of modelled and measured concentrations of several pesticides in surface water and soil during and after specific rain events following application. The field experiments were designed to obtain data on rainfall, outflows of water, pesticide application rates and concentrations in soil and water. The results were satisfactory for the undissociated pesticides (atrazine, carbofuran, dimethoate, isoproturon, lindane, simazine and trifluralin), whose concentrations in water were mostly predicted within an order of magnitude of measured data. The results for the dissociated pesticides (dichlorprop, MCPA, mecoprop) were less satisfactory, giving generally much higher predicted concentrations in water. The use of the SoilFug model is suggested for the calculation of predicted environmental concentrations (PECs) in water, since it generally produces acceptable results from a relatively small set of input data, most of which is generally available.

Joint Global Ocean Flux Study (JGOFS).

Abstract: tent of an agricultural soil over the last century. Environmental Science and Technology 23, 95 101 JONES, K. C.; GRIMMER, G.; JACOB, J.; JOHNSTON, A. E. (1989 b): Changes in the polynuclear aromatic hydrocarbon content of wheat grain and pasture grassland over the last century from one site in the UK. Science of the Total Environment 78, 117-130 JONES, K. C.; SANDERS, G.; WILD, S. R.; BURNETT, V.; JOHNSTON, A. E. (1992): Evidence for a decline of PCBs and PAHs in rural vegetation and air in the United Kingdom. Nature 356, 137140 KJELLER, L.-O.; JONES, K. C.; RAPPE, C.; JOHNSTON, A. E. (1991): Increases in the polychlorinated dibenzo-p-dioxin and -furan content of soils and vegetation since the 1840s. Environmental Science and Technology 25, 1619 1627 MACKAY, D. (1991): Multi-media Environmental Models: The Fugacity Approach. Lewis Pub. Co., Michigan, USA MACKAY, D.; SHIU, W. Y.;/VIA, K. C. (1991): Illustrated Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals. Vol. 1. Monoaromatic Hydrocarbons, Chlorobenzenes, and PCBs. Lewis Pub. Col., Michigan, USA M-ACKAu D.; SHIU, W. Y.;/viA, K. C. (1992): Illustrated Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals. Vol. 2. Lewis Pub. Co., Michigan, USA McLAcHL,~, M. S. (1993): Mass balance of polychlorinated biphenyls and other organochlorine compounds in a lactating cow. J. Agric. Food Chem. 41, 474 -480 McLACHLAN, M. S.; HUTZINGER, O. (1990): Accumulation of organochlorine compounds in agricultural foodchains. In: Organohalogen Compounds 1. Ecoinforma Press, Bayreuth MOZA, P.; WEISGERBER, I.; KLEIN, W. (1979): Studies with 2,4',5-trichlorobiphenyl-14C and 2,2',4,4',6-pentachlorobiphenyl14C in carrots, sugar beets, and soil. Journal of Agricultural Food Chemistry 27, 11201124 OEHME, M. (1991): Dispersion and transport paths of toxic persistent organochlorines to the Arctic levels and consequences. Science of the Total Environment 106, 43 53 OTTAR, B. (1981): The transfer of airborne pollutants to the Arctic region. Atmos. Environ. 15, 1439-1445 SANDERS, G.; JONES, K. C.; H~MILTON-TAvLOR, J.; DrY, R, H. (1993): Concentrations and deposition fluxes of polynuclear aromatic hydrocarbons and heavy metals in the dated sediments of a rural English lake. Environmental Toxicology and Chemistry 12, 1567-1581 SWACKHAMER, D. L.; EISENREICH, S. J. (1991): Processing of Organic Contaminants in Lakes. p. 33 86. In: Organic Contaminants in the Environment. (K. C. JONES, Ed.), Elsevier Applied Science Publishers WANG, M.-J.; JoNEs, K.C. (1994): The behaviour and fate of chlorobenzenes in spiked and sewage sludge amended soil. Environ. Sci. Technol. 28 (in press) W~IA, F.; MACKAY, D. (1993): Global fractionation and cold condensation of low volatility organochlorine compounds in polar regions. Ambio 22, i0 18 WILD, S.R.; JONES, K.C. (1992): Organic chemicals entering agricultural soils in sewage sludges: screening for their potential to transfer to crop plants and livestock. Science of the Total Environment 119, 85 -119 WILD, S. R.; JONES, K. C. (1994): Polynuclear aromatic hydrocarbons in the United Kingdom environment: a preliminary source inventory and budget. Environmental Pollution (in press) WILD, S. R.; WATERHOUSE, K. S.; McGRATH, S. P.; JONES, K. C. (1990): Organic contaminants in an agricultural soil with a known history of sewage sludge amendments: polynuclear aromatic hydrocarbons. Environmental Science and Technology 24, 1706-1711 WILD, S. R.; I-L~gRAD, S. J.; JONES, K. C. (1994): The influence of sewage sludge amendment to agricultural land on human exposure to polychlorinated dibenzo-p-dioxins and -furans. Environmental Pollution 83, 357-369

Deposition of semivolatile organic compounds to spruce needles : II. Experimental evaluation of the relative importance of different pathways.

Abstract: The accumulation of atmospheric HCB, Lindane, DDT, DDE and the PCB congeners 52, 101, 138, 153 and 180 in spruce needles (Picea abies) was investigated at outdoor locations and in greenhouses supplied with ambient air. The air supply of the greenhouses was modified to dinstinguish between gaseous and particle-associated deposition of the compounds. Accumulation of the compounds occurred in all spruce except those grown in the greenhouse where the gaseous concentration of the compounds was reduced. Spruce grown in the greenhouse supplied with particle-free ambient air behaved similarity to those grown outdoors. Protecting the spruce located outdoors from rain did not affect the accumulation. The results show that under spring and summer conditions at a typical central European rural environment dry gaseous deposition is the dominant pathway of these compounds to needles.

Deposition of semivolatile organic compounds to spruce needles

Abstract: The deposition of atmospheric tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, α-HCH, γ-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.

Ancient atmosphere- Validity of ice records

Abstract: The following article of Z. JAWOROWSKI addresses one of the key issues in global environmental research with potentially far-reaching implications on the future of our industrial development. As the consequences of global climate changes caused by increasing carbon dioxide levels may ultimately lead to legislative measures to curb fossil fuel consumption with almost unpredictable effects on our standard of living, the critical discussion of all facets leading to the postulate of global warming deserves utmost attention. Every single parameter relevant to this suggestion must be carefully scrutinized.

Bioconcentration of superlipophilic persistent chemicals : Octachlorodibenzo-p-dioxin (OCDD) in fish.

Abstract: According to present understanding, persistent superlipophilic chemicals — such as octachlorodibenzo-p-dioxin, octachlorodibenzofuran, Mirex etc — with log Kow > 6 and cross sections > 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 Kow 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 we recommend: (i) flow-through systems, kinetic method (OECD guideline No. 305 E) (ii) ambient concentrations < water solubility (iii) during the uptake and especially during the elimination phase no toxic effects of the test organisms should occur.

Surfactant solubilization of hydrophobic compounds in soil and water

Abstract: Reductions in the apparent soil-water partition coefficients (Kd*) 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, Kd* was reduced by 2–3 orders of magnitude, but even far below CMC at environmentally relevant surfactant concentrations significant reductions in Kd* were observed. The plot of the soil-water partition coefficient (Kd) divided by Kd* versus the concentration of SDS allowed for the calculation of monomer (Kmnoc) and micellar (Kmcoc) surfactant-water partition coefficients normalized to organic carbon for each PCB congener. Kmnoc values were comparable with published values for the partition of PCBs between natural dissolved organic matter and lake water. Kmcoc values were up to 30 times higher than Kmnoc 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.

Guide values for contaminated sites in Baden-Württemberg.

Abstract: The treatment of hazardous sites in Baden-Wurttemberg is based on three legal documents: the state waste disposal art (LAbfG, 1990), the assessment committee directive (KommissionsVO, 1990), and the guide values directive (UM & 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-Wurttemberg (UM & 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: The guideline is the only directive of its kind in the world that regulates both concentrations and fluxes of contaminants into groundwater.

Environmental risk assessment of existing chemicals.

Abstract: Most of the existing chemicals of high priority have been released into the environment for many years. Risk assessments for existing chemicals are now conducted within the framework of the German Existing Chemicals Program and by the EC Regulation on Existing Substances. The environmental assessment of a chemical involves: a) exposure assessment leading to the derivation of a predicted environmental concentration (PEC) of a chemical from releases due to its production, processing, use, and disposal. The calculation of a PEC takes into account the dispersion of a chemical into different environmental compartments, elimination and dilution processes, as well as degradation. Monitoring data are also considered. b) effects assessment. Data obtained from acute or long-term toxicity tests are used for extrapolation on environmental conditions. In order to calculate the concentration with expectedly no adverse effect on organisms (Predicted No Effect Concentration, PNEC) the effect values are divided by an assessment factor. This assessment factor depends on the quantity and quality of toxicity data available.

On-line speciation of arsenical compounds in fish and mussel extracts by HPLC-ICP-MS.

Abstract: The separation and determination of sub-μmol/l 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 μmol 1−1.

Determination of atrazine in rainfall and surface water by enzyme immunoassay.

Abstract: 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 μg/L with a middle of the test at 0.2 μg/L. 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 μg/L for rainwater and up to 15 μg/L for surface waters. The highest concentrations were found in agricultural areas, while in the investigated national parks up to 0.56 μg/L could be detected in rain water. 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 μg/m(2) · yr were observed in the national parks and 10-180 μg/m(2) · yr at the agricultural sites. Comparison of results obtained by enzyme immunoassay and GC/MS showed a good correlation of r = 0.95.

Immunoassay monitoring of polychlorinated biphenyls (PCBs) in the Great Lakes

Abstract: 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.

Sorption kinetics of chlorinated hydrophobie organic chemicals : Part I: The Use Of First-Order Kinetic Multi-Compartment Models.

Abstract: This is the first of a two-part series describing the Sorption kinetics of hydrophobic organic chemicals. This paper discusses the use of first-order kinetic compartment models in environmental studies, of subjects such as bioaccumulation and sorption. A comprehensive mathematical description and model calculations are presented. Differences between these models and the pharmacokinetic compartment models will be indicated, emphasis being given to the use of the former in sorption studies.

Pesticides and groundwater quality protection : Calibrating a simple model for ranking the contamination potential.

Abstract: A simple approach for ranking the leaching of pesticides from surface soil is presented and tentatively calibrated with field data from an agricultural area. The approach is based on the calculation of a leaching index indicating the proportion of active ingredient, with respect to the quantity applied, leaching from a soil model in a given time interval (one year). In the selected area, 85 wells tapping an unconfined aquifer were sampled for groundwater pesticide residue analysis, in order to explore the index region between leachers and nonleachers.

Fate of pulp mill effluent compounds in a finnish watercourse.

Abstract: Chloroorganic chemicals emitted from the pulp and paper mill at nekoski in central Finland were monitored for several years. Concentration time series are used for evaluating the environmental fate and the applicability and validity of an exposure models. Fitted elimination rates of 3,4,5-Tri-, 4,5,6-Tri-, Tetrachloroguaiacol and 2,4,6-Trichlorophenol are approx. 0.22 d-1, or rather the half-lives are approx. 3 days. The elimination is most likely by biodegradation and transport-controlled. For 2,3,6-trichloro-p-cymene, fate simulations indicate significant volatilization and sedimentation. Good agreement is achieved with a one-dimensional steady-state box model, except for concentrations in fish. For a reliable assessment of environmental damage, laboratory experiments, monitoring and simulations need to be in tune.