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This chapter provides information available on transport and on transformation and degradation of pesticides in soil, and possibilities of prediction. Pesticides may be absorbed by soil organic matter as well as by inorganic soil fractions, and the relation between adsorption at sites depends on soil properties as well as chemical structure of the pesticide. Adsorption by inorganic and organic matter is not by just one mechanism of pesticide-soil interaction. Physical, physicochemical, and chemical processes are involved. Adsorption coefficients and constants related to soil organic carbon have been shown to be correlated with simpler physicochemical parameters. Mobility of pesticides in soil is related to adsorption, on the one hand, and the mass flux of dissolved fractions, on the other hand. Binding of pesticides to natural soil constituents is of paramount importance for their ecotoxicological evaluation. Volatilization of pesticides from soil is the transfer of the pesticides as a gas through the soil-air interface under environmental conditions.

14C-isoproturon residues were incorporated in wheat plants by growing seedlings for 18 days in quartz sand with nutrient solution which was treated with ring-labeled 14C-isoproturon, resulting in 14C-concentration equivalent to 15.4 nmol isoproturon per g dry shoot mass. The residues were characterized by extraction and HPLC-analysis, and were shown to consist of unchanged isoproturon, soluble metabolites (monodemethyl-isoproturon, didemethyl-isoproturon, 1-OH-isoproturon, 2-OH-isoproturon, 2-OH-monodemethyl-isoproturon, 2-OH-didemethyl-isoproturon, isopropenyl-isoproturon and unidentified metabolites), as well as nonextractable residues. Dried plant samples containing these residues were mixed with soil samples originating from different farming systems, and mineralization to 14CO2 was determined in a closed aerated laboratory system. In addition, the microbial biomass and bioactivity of soils were estimated by determination of substrate-induced heat output, basal heat output, metabolic heat quotient, total adenylate content and adenylate energy charge. Significant positive correlations between 14CO2 production or adenylate content and microbial biomass were observed in three soils; 14CO2 production and total microbial biomass were highest in soil samples from organic farming. Soil samples from a former hops plantation contaminated with copper from previous fungicide applications did not fit this correlation, but exhibited a higher mineralization capacity per unit of microbial biomass. Our results indicate that general soil microbial parameters in many cases are insufficient to describe the influence of biotic factors on the fate of pesticides in soil.

The ability of the white rot fungus Phanerochaete chrysosporium to degrade isoproturon was tested in solid substrate fermentation (SSF) cultures using straw as substrate/carrier material. The role of the lignin degrading enzymes, lignin peroxidase (LiP) and manganese peroxidase (MnP), in the degradation of the herbicide was also studied. Isoproturon concentration and LiP and MnP activities were followed in sterile straw cultures of the fungus. In vitro degradation tests with pure LiP and MnP were performed. P. chrysosporium in straw cultures was able to degrade 91% of the herbicide isoproturon in 14 days of incubation. A sharp decrease of isoproturon coincided with the largest MnP activity. Although LiP activity was also present, its role in SSF is unclear. The in vitro tests showed a strong isoproturon oxidation by LiP and a slower oxidation by MnP in the presence of Tween 80 probably by a lipid peroxidation process. Two N-demethylated metabolites were identified in pure enzyme tests and in SSF cultures. Several unidentified isoproturon derivatives, most likely hydroxylated, were also formed in both systems. The different pattern of derivatives detected in pure LiP and MnP tests showed a completely different metabolism by these two enzymes.

The genetic modified Pseudomonas fluorescens Br 12, resistant to kanamycin and rifampycin, was used to follow the co-transport of the organochlorine acaricide dicofol through a nonsterilized soil column. P. fluorescens was found to bioaccumulate dicofol with the highest bioconcentration factor of 279 within 30 min. Separate soil column experiments where applied P. fluorescens or [14C]dicofol were submitted to heavy rain simulation did not reveal any correlation between the distribution patterns of P. fluorescens and [14C]dicofol in the leachate fractions (r=0.3). Similar experiments with P. fluorescens that previously had bioaccumulated [14C]dicofol demonstrated a high correlation of these bacteria and radioactivity in the leachate fractions (r=0.8). The total recovery of radioactivity in the leachate, when [14C]dicofol was previously bioaccumulated in bacteria, was more than two times higher (4.5%) than the total recovery of radioactivity in the leachate when [14C]dicofol was directly applied in the soil (2%). This indicates cotransport by Pseudomonas. Fractionation and analysis of soil columns indicated that most of the bioaccumulated dicofol was rapidly released and adsorbed in soil, while bacteria moved down by leaching.

The biomineralization of [14C]glyphosate, both in the free state and as 14C-residues associated with soybean cell-wall material, was studied in soil samples from four different agricultural farming systems. After 26 days, [14C]carbon dioxide production from free glyphosate accounted for 34–51% of the applied radiocarbon, and 45–55% was recovered from plant-associated residues. For three soils, the cumulative [14C]carbon dioxide production from free glyphosate was positively correlated with soil microbial biomass, determined by substrate-induced heat output measurement and by total adenylate content. The fourth soil, originating from a former hop plantation, and containing high concentrations of copper from long-term fungicide applications, did not fit this correlation but showed a significantly higher [14C]carbon dioxide production per unit of microbial biomass. Although the cumulative [14C]carbon dioxide production from plant-associated 14C-residues after 26 days was as high as from the free compound, it was not correlated with the soil microbial biomass. This indicates that the biodegradation of plant-associated herbicide residues, in contrast to that of the free compound, involves different degradation processes. These encompass either additional steps to degrade the plant matrix, presumably performed by different soil organisms, or fewer degradation steps since the plant-associated herbicide residues are likely to consist mainly of easily degradable metabolites. Moreover, the bioavailability of plant-associated pesticide residues seems to be dominated by the type and strength of their fixation in the plant matrix. ©1997 SCI

Pentachlorophenol (PCP)-14C was applied to two soils (50 and 200 mg/kg dry weight) and incubated for 20 weeks at room temperature. Total and extractable 14C-residues decreased continuously, whereas soil-bound residues increased. ATP-content, substrate-induced soil respiration and substrate-induced heat output did not recover during decline and binding of PCP; in the soils dosed with 200 mg/kg, ATP-content reached nearly zero. After removal of the extractable 14C-residues by exhaustive extraction, significant effects of the remaining soil-bound residues (6–30 mg/kg) on the microflora of fresh soils were observed only by ATP-content.

The acute toxicity (48-hr LC50) of lindane (gamma-HCH) to 16 fish species, belonging to eight families, ranges from 22 to 900 micrograms/liter (mean: 150 micrograms/liter). A significant positive linear relationship between the lipid content (% on a wet weight basis) of the fishes and their toxicity to gamma-HCH was found. If the toxicity is referred to 1% lipid, 48-hr LC50 values range between 13.2 and 32 micrograms/liter, and thus the coefficient of variation of the mean is reduced from 139 to 22%. It is concluded that the lipids of aquatic organisms serve as a protective reservoir against the toxic effects of lindane and other lipophilic, relatively persistent organic chemicals, because they are bioconcentrated mainly in the body lipids. Therefore, in organisms with high lipid content, only a relatively small fraction of the hydrophobic chemical can reach target organs (nerves, liver, etc.) and/or receptors. For comparing toxicity data of organic chemicals to aquatic organisms, the total lipid content of the organisms must be considered. The results of this investigation are important in comparative environmental toxicology for risk assessment of freshwater and marine organisms.

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.

The most convincing argument against the hypothesis that persistent superlipophilic chemicals with log KOW >6, such as OCDD are bioconcentrated - if at all - to a low extent is that in all these bioconcentration experiments, except of 2,3,7,8-TCDD, exposure concentrations have been applied which exceeded water solubility by several orders of magnitude. In this paper, a indirect method for the estimation of bioconcentration factor (BCF) of OCDD is presented: The BCF value on a lipid basis (BCFL) of 8.5∗107 in fish was obtained from an extrapolation fo a linear log/log relationship for kinetically measured BCFL data in fish and the OCDD concentration in the water up to water solubility of this chemical.

Prediction of the bioconcentration of organic chemicals from water by aquatic organisms has important applications in the management of hazardous chemicals. This study gives a compilation of bioconcentration factors on a wet weight basis (BCFw) of 52 organic chemicals by Daphnia magna from aqueous solution. The bioconcentration factors for the chemicals in Daphnia were successfully correlated with their n-octanol/water partition coefficients (log Kow) using a linear regression analysis. In addition to the ordinary least-square regression technique, the geometric mean regression technique is also used because this takes into account deviations in Kow values. Both results show that the Kow value of a chemical is a good predictor of the BCF in Daphnia. The BCF-Kow relationships between Daphnia, algae (Chlorella), and mussels (Mytilus edulis) are compared with each other.

Trotz Volatilitat und Bioabbau sind Ruckstande von Pflanzenschutzmitteln und anderen organischen Fremdstoffen uber Jahre im Boden nachzuweisen. Der Ruckgang der Fremdstoffruckstande im Boden erfolgt zunachst in einerschnellen Phase, die in etwa einer Kinetik erster Ordnung entspricht, gefolgt von einerviel langsameren Ruckgangsphase. Bei manchen Stoffen kommt bei einer gewissen Restkonzentration der Abbau fast zum Stillstand. Derartige Kurvenverlaufe treffen nicht nur auf die Ruckstande derunveranderten Ausgangssubstanzen, sondern auch auf dieGesamtruckstande zu, die extrahierbareUmwandlungsprodukte undgebundene Ruckstande enthalten. Der Anteil von extrahierbaren Umwandlungsprodukten und gebundenen Ruckstanden am Gesamtruckstand nimmt mit der Zeit zu. Fur das Phenylharnstoffherbizid Buturon wurde auch einequalitative Anderung der Umwandlungsprodukte mit der Zeit beobachtet. Dasselbe gilt fur die imSickerwasser ausgewaschenen Umwandlungsprodukte. Die Bindungsmechanismen, durch die nichtextrahierbare Ruckstande entstehen konnen, werden diskutiert. Eine Vorhersage des Langzeitverhaltens organischer Chemikalienruckstande im Boden ist derzeit noch nicht moglich.

[ phenyl - 14 C]Monolinuron was applied (2.5 and 1.9 kg/ha) to the soil surface of an outdoor lysimeter in two successive years; then, potatoes were grown. Total recovery of 14 C in soil, plants, and leached water was about 55% (of 14 C applied) after the first growing period and about 43% after the second growing period. Radioactivity in soil contained 77.1% (based on total 14 C recovered in soil) bound residues, 15% monolinuron, and the following conversion products: N -(4-hydroxyphenyl)- N′ -methoxy- N′ -methylurea, N -(4-chlorophenyl)- N′ -methylurea, N -(4-chlorophenyl)methylcarbamate, N -(4-chlorophenyl)- N -methyl-methylcarbamate, and 4-chloroformanilide. The leachate contained 0.8% (based on total 14 C recovered in leachate) N -(4-hydroxyphenyl)- N′ -methoxy- N′ -methylurea. Potato plants contained 0.106 mg/kg radioactive residues in peeled tubers after one growing period and 15.94 mg/kg in the tops; after two growing periods, peeled tubers contained 0.091 mg/kg and tops contained 18.87 mg/kg radioactive residues. These residues consisted of bound 14 C (57.9% of total 14 C recovered in plants), N -(4-hydroxyphenyl)- N′ -methoxy- N′ -methylurea, N -(4-chlorophenyl)- N′ -methylurea, N -(4-chlorophenyl)methylcarbamate, N -(4-chlorophenyl)- N -methyl-methylcarbamate, and 4,4′-dichloroazobenzene.

Bioaccumulation of chemicals by aquatic organisms, especially fish, mussels and Daphnia, is an important criterion in risk assessment. Bioconcentration from water must be considered in context with toxicity, biotic and abiotic degradation and other physical-chemical factors in order to protect the freshwater and marine environments with their organisms. Furthermore, it is necessary to prevent human exposure from contaminated aquatic food, such as fish, mussels, and oysters. This review outlines the factors such as toxic effects, bioavailability, chemical concentration in the water, pH of the water, and lipid content of the organisms, which are known to affect the bioconcentration of chemicals in aquatic organisms. Quantitative structure-activity relationships (QSARs) for predicting the bioconcentration potential of chemicals in algae, Daphnia, mussels, and fish are presented. Specific classes of organic chemicals, such as endocrine-disrupting chemicals (EDCs), super-hydrophobic persistent organic pollutants (POPs) (2,3,7,8-tetrachlorodibenzo-p-dioxin, octachlorodibenzo-p-dioxin, Mirex, and Toxaphene), tetrachlorobenzyltoluenes (TCBTs), polybrominated benzenes (PBBz), polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), polychlorinated diphenylethers (PCDEs), nitro musk compounds (NMCs), polycyclic musk fragrances (PMFs), and sun screen agents (SSAs) are critically reviewed and discussed. Furthermore, predictions for some metabolites, especially hydroxylated aromatics, of these chemical classes which may have endocrine-disrupting effects are made. The selected bioconcentration factors on a wet weight basis (BCFw) and on a lipid basis (BCFL) in aquatic organisms, such as algae (Chlorella sp.), water fleas (Daphnia sp.), mussels (Mytilus edulis), oysters (Crassostrea virginica), and different fish species, of these chemicals are presented in tables. Furthermore, the chemical structure, physico-chemical properties, such as selected log KOW values, and other data are compiled. In the cases where no bioconcentration factors (BCFs) were published the BCF values of chemicals in fish and mussels were predicted from QSARs using the n-octanol/water partition coefficient (KOW) as the basic parameter. A new classification scheme for organic chemicals by their hydrophobicity (log KOW) and by their worst-case bioconcentration factors on a lipid basis (BCFL) is also presented.

Polychlorinated bomanes, the main components of Toxaphene, are bioconcentrated in aquatic organisms to a high extent. However, up to this time no bioconcentration tests with individual chlorinated bomanes in aquatic organisms have been performed. Therefore, the bioconcentration factors (BCFs) of seven selected persistent chlorinated bornane congeners which are regularly found in aquatic organisms, were predicted from their n-octanol/water partition coefficients (log K ow . Furthermore, these BCF values were compared with the measured bioaccumulation factors (BAFs) in zooplankton and different fish species from the aquatic environment.

The amount of non-extractable residues (NER) of organic xenobiotics in the soil can considerably exceed the amount of extractable residues which are accessible to normal residue analysis. The NER therefore present a burden to the soil, the toxicological and ecotoxicological potential of which is largely unknown. For the characterization of bound residues and their binding type, special solubilization methods such as supercritical fluid extraction are applied and experiments with radiolabeled model polymers are performed. Mineralization experiments with [(14)C] labeled xenobiotics in natural soil show that a total degradation is still also possible in the environment when in a bound form. Ecotoxicological effects of non-extractable residues may be recorded when their concentration is high, when the parent compound exhibits a high ecotoxicity and the applied detection method is sufficiently sensitive.

The mode of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] adsorption to humic substances is still uncertain, mainly because of the large heterogeneity of humus and its poor molecular characterization. In this study, four humic fractions were isolated from a peat and a volcanic soil by three different extraction mechanisms: charge repulsion (NaOH extraction), ligand exchange (pyrophosphate extraction, Na 4 P 2 O 7 ), and hydrogen-bonding disruption (extractions by aqueous mixture of acetone and dymethyl sulphoxide, DMSO). These four humic fractions showed consistent differences in molecular structure between the two soils. Humic fractions extracted by acetone had the largest content of aliphatic C, whereas those obtained by the pyrophosphate solution were richest in aromatic C. Sorption isotherms of 14 C-labeled atrazine conducted on the four humic fractions showed that, for both soils, the order of adsorption was acetone > NaOH > DMSO > Na 4 P 2 O 7 , whereas the order for desorption was the reverse. The relation between results of atrazine interaction and the molecular structure of humic matter indicates that the aliphatic C content of soil organic matter may be one of the parameters controlling atrazine adsorption to soils. Hydrophobic interactions and conformational flexibility in the aliphatic portions of humic matter controlled the adsorption of atrazine in the interior of humic self-associated aggregates and the degree of desorption found both in water and methanol. Conversely, the conformational rigidity conferred to humic fractions by a large content of aromatic moieties appeared conducive only to surface adsorption and thus to easier herbicide desorption.

The bioconcentration factors of 14C-labeled chlorinated benzenes in plants from soil were quantified in short-term laboratory experiments and correlated to Kow. The correlation was negative for barley and positive for cress. In order to interpret these opposite results, the log/log correlation between partition coefficients and Kow of the chemicals was established also for each step of the uptake, via both roots and leaves. For the first step of root uptake--the partition of the chemicals from soil solids into soil water--the correlation with Kow was negative, whereas it was positive for the second step, the partition roots/soil water, of both plant species. Similarly, the correlation between the first step of foliar uptake--the partition of the chemical from soil into air--and Kow was negative, and that between the second step--the partition between aerial plant parts and air--and Kow was positive for both plant species. The slopes of the regression lines differed between plant species. It may be concluded that Kow can be used as a parameter to predict the uptake of chemicals from soil by plants only if the same class of chemicals and the same plant species is considered.

This paper provides an explanation for a 40-fold difference in the acute toxicity (LC50) of gamma-hexachlorocyclohexane (gamma-HCH, Lindane) in 14 different fish species, based on well recognized principles of toxicokinetics and toxicodynamics in combination with a compilation of data from the literature and some original data. The 48-h median lethal concentration (48-h LC50) of gamma-HCH in 14 fish species, belonging to 6 families, range from 22 to 900 micrograms/l. A significant positive linear relationship was found between lipid content (% of wet weight) and the 48-h LC50 of gamma-HCH in these fish species, revealing that the toxicity of gamma-HCH in various fish species is decreasing with increasing total lipid content. If median lethal concentrations are normalized for 1% lipid content, then the range of 48-h LC50s is reduced to between 18 and 32 micrograms/l. It is concluded that lipids of aquatic organisms can serve (among other functions) as a protective storage site against the toxic effects of gamma-HCH and, possibly, of other lipophilic, persistent organic chemicals which are bioconcentrated in body lipids. Therefore, in organisms with higher lipid content, a smaller fraction of a lipophilic chemical will reach target organs (liver, lung, central and peripheral nerves, etc.) to cause adverse effects. Results suggest that this correlation can be used to extrapolate the acute toxicity (48-h LC50) of gamma-HCH to other fish species if their lipid content is known. Furthermore, the data generated by extrapolation of this correlation could be useful in the environmental risk assessment of freshwater and marine organisms.

Lipophilic chemicals such as chlorinated hydrocarbon insecticides and other persistent chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are fat soluble chemicals and are readily bioconcentrated in animal fat depots. The modifying role of the body fat content in the toxicity of chlorinated cyclodiene insecticides to insects and in the toxicity of TCDD to different mammals was investigated. The single oral acute 30-day LD50 data of TCDD in different mammals are presented and correlated with their total body fat content. A two linear regression equation with log/log values was obtained. It is concluded that the storage of TCDD and other related lipophilic and persistent chemicals in lipids of organisms is, in a sense, a detoxication mechanism by which the compounds are removed from sites of action and/or receptors. Therefore, terrestrial organisms such as insects and mammals with higher total body fat content can accumulate and tolerate higher chlorinated hydrocarbon insecticide and TCDD doses than organisms with lower fat content. The different sensitivity of mammals of various species, strains, body weight, sex, age, etc. to acute toxicity of TCDD and related lipophilic persistent chemicals can mainly be explained by differences in total body fat content.

The bioconcentration factors (BCFs) of pentachlorophenol (PCP) in different tissues, organs and body fluids of humans were calculated by two methods: 1) from daily intake of PCP and its measured concentrations in different tissues and, 2) from measured half-life and measured PCP concentrations in the human body at steady state using a linear one compartment pharmacokinetic model. The BCFs (based on wet weight) in liver, brain, blood, spleen and adipose tissue of humans as calculated by method 1 were 5.7, 3.3, 1.4, 1.4, and 1.0, respectively. The figures obtained by method 2 were in good agreement to those obtained by method 1.

Under the influence of 2,5, or 10 μg/g atrazine, the degradation of 10 μg/g of the detergent n-dodecylbenzenesulfonate- 14 C to 14 CO 2 in an Alfisol soil is inhibited for about 12 days, then stimulated. The overall influence of atrazine after 38 days is a slight inhibition of 14 CO 2 -formation.

[14C]Aldrin was applied to soils (about 3kg/ha) in outdoor boxes at various locations (Germany, England, and United States), and crops were cultivated (maize, wheat, sugar beets, and potatoes). In the following year, crop rotation experiments were carried out in the same soils without retreatment; in addition, wheat was grown in soils retreated with [14C]aldrin (3.5 kg/ha). After the harvest of both years, the distribution of aldrin and major metabolites (dieldrin; photodieldrin; hydrophilic metabolites including dihydrochlordene dicarboxylic acid; an unidentified nonpolar compound X; and unextractable metabolites) was determined in plants, soils, and leaching water. Two further conversion products, photoaldrin and aldrin-trans-diol, occurred in trace amounts only in a few samples. Metabolic pathways for aldrin under outdoor conditions are presented. The distribution of radioactive residues in soils and plants as well as their quantitative chemical composition are discussed, and comparisons are made between the different experimental sites, the crops, the first and second year, and retreated and nonretreated samples. The quantitative results are compared to those of field trials.

A quantitative relationship was found to exist between the lipophilicity (n-octanol/water partition coefficient) of pentachlorophenol, dieldrin, hexachlorobenzene, 2,3,7,8-tetrachlorodibenzo-p-dioxin, Σ DDT, polychlorinated biphenyls, α-, β-, γ- and δ -hexachlorocyclohexane and their bioconcentration factor (BCF) in human adipose tissue. The equations were used to predict the bioconcentration factors of some chlorinated aromatic chemicals.

The formation of 14CO2 from 13 14C-labelled organic chemicals in aerobic and anaerobic suspended soil was determined. After 5 days at 35°C, 14CO2 was between 70.1% (urea, anaerobic) and < 0.1% (2,6-dichlorobenzonitrile and hexachlorobenzene, aerobic and anaerobic) of the 14C initially applied.

The persistence of pentachlorophenol-14C and of HgCl2 in soil, their damage to the microorganisms and the reversibility of the damage depend on soil type and on the concentrations of chemicals. In soils of lower organic matter content, residue losses of both chemicals are higher, the damage to soil microflora is also higher, and the reversibility of the damage is lower than in soil with high organic matter content.

The effective concentrations of 15 chemicals, inhibiting the cell growth of the alga Scenedesmus subspicatus by 10 % and 50 % during 96 hours, have been investigated in a static test under controlled laboratory conditions.

Outdoor experiments with [14C]hexachlorobenzene, [14C]pentachlorobenzene, [14C]1,2,4-trichlorobenzene, and [14C]benzene in soil-crop systems indicate that the formation rate of bound residues in soil and plants, expressed as bound residues in percentage of total residue in the sample, decreases with increasing number of chlorine in the molecule and, thus, with increasing chemical stability. The time course of formation and fate of bound residues in soil and plants is characterized by a very slow decrease of residue levels in soil, indicating that biodegradation of bound residues hardly exceeds their reformation from the parent compound during one vegetation period, and by a decrease of residue levels in plants. The portion of bound residues as compared to the total residue increases with time, indicating that bound residues are more persistent than the parent compounds and their soluble metabolites; benzene is an exception. Cress plants, in general, contain less bound residues than do barley plants. Again, benzene is an exception. In deeper soil layers, soil-bound residues occur also. The ratio between bound and extractable residues does not differ to a larger extent between the soil layers.

Pentachlorophenol, depending on the applied concentration, reduces the activity of some microorganisms, as measured by the iron reduction test. The test is more sensitive, if the procedures reported in literature are modified, including the use of glucose as a source of energy instead of yeast extract.

A ion-paired reverse-phase high-pressure liquid chromatographic method using fluorescence detection for the determination of adenine nucleotides in soil has been developed. Dimethylsulfoxide (DMSO) was added to soil to stop biological activity; then, phosphate buffer (pH 11.7) was added for a further dispersion. An aliquot of soil suspension was mixed with an equal volume of nucleotide releasing agent (NRB) and then sonified. The adenylates separated from the mixture by passing through a membrane filter were reacted with chloroacetaldehyde to form their corresponding 1.N 6 -etheno-derivatives. These derivatives were eluted on an ODS (C-18) column with 0.05 M ammonium acetate, 1.0 mM EDTA and 0.2 mM tetrabutylammonium hydrogen sulfate (pH 6.3) mixed with methanol (water phase/methanol 9:1 v/v) as a mobile phase. The minimum detection limits of this analytical method were 0.2, 0.1 and 0.05 μg·g −1 dry soil for ATP, ADP and AMP in soil, respectively. The recoveries of soil samples fortified with 1.0, 2.0 and 5.0 μg·g −1 dry soil of the adenine nucleotides were > 80%.

A simple method for the extraction and determination of adenosine 5′-triphosphate (ATP) in soil is described. ATP was extracted by stirring with dimethyl sulphoxide (DMSO), followed by adding 0.01 M trisodium phosphate (Na 3 PO 4 ) buffer solution for a further dispersion. The ATP content was quantitatively measured by luciferin-luciferase system employing a standard addition technique. The method was most efficient in comparison with 7 other extraction procedures. The recoveries of ATP in spiked soil were found to be approximately 100 %. ATP contents in 16 selected soils were in ranges of 0.76±0.05 – 7.79±0.83 μ g/g (dry weight). A significant correlation between ATP amounts and biomasses in these soils was also observed.

Donnees experimentales sur le bilan massique, la mobilite dans le sol, la degradation et la conversion dans le sol, l'absorption par les plantes cultivees, pour diverses conditions de laboratoire et en exterieur. Les produits de conversion sont isoles et identifies par combinaison de la chromatographie en phase gazeuse et de la spectrometrie de masse

Six methods described for the determination of total microbial activity were tested in two soils for their suitability to detect potential effects of three pesticides. Total microbial activity is represented by measuring the heat output and the ATP-amount. Methods involving the arginine ammonification, the hydrolysis of fluorescein diacetate and the Fe (III)-reduction show an enhanced sensitivity for special microbial groups.

The extraction of ATP from soils with the TCA- and NRB ®-methods shows qualitative and quantitative differences. A combination of both methods results in a higher yield of extracted ATP and in a solution of low optical quenching.

A list of environmental chemicals detectable in adipose tissue and/or milk of non-occupationally exposed humans is presented. Besides their physiochemical properties (n-octanol/water partition coefficient and water solubility), their acceptable daily intake (ADI) values, production figures, fate in the environment, concentrations in human adipose tissue, and data from total diet studies from market basket investigations are given. Average bioconcentration factors (BCF) of polychlorinated biphenyls (PCBs), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), DDT, hexachlorobenzene (HCB), dieldrin, hexachlorocyclohexane isomers (alpha-HCH, beta-HCH, gamma-HCH, delta-HCH), pentachlorophenol (PCP), and 3,5-di-tert-butyl-4-hydroxytoluene (BHT) in human adipose tissue are calculated. The bioconcentration factors (wet wt basis) of these compounds are between 3 and 47 times higher in humans than in rats. The environmental chemicals are divided into three groups in respect to their bioconcentration factors in human adipose tissue: group I, high BCF (greater than 100); group II, medium BCF (10-100); and group III, low BCF (less than 10). The bioconcentration factors are useful for hazard assessment of chemicals to humans.

Residues of hexachlorobenzene-14C were found in all parts of wheat plants grown from treated seeds or in contaminated soil. Besides the parent compound and bound residues in plants and soil, very small amounts of soluble acidic metabolites were present in plants, which were characterized and determined quantitatively.

The vapour pressures of nine organic chemicals adsorbed on silicagel were determined by a method which can be standardized. They were compared with those of the non-absorbed, free compounds (range 6 × 10 −3 – 7 × 10 4 Pa).