Drosophilin A methyl ether (DAME) and other chlorinated dimethoxybenzenes in fungi and forest litter from Sweden

Fungi and substrates undergoing fungal decomposition were collected from forests in northern and southern Sweden and analyzed for chlorinated dimethoxybenzenes (DMBs). Specimens were fungi fruiting bodies, rotting wood, forest litter and underlying humus. Targeted compounds were DAME (1,2,4,5-tetrachloro-3,6-DMB) and related fungal secondary metabolites. A screening procedure was developed which involved soaking the specimens in ethyl acetate followed by analysis by capillary gas chromatography – mass spectrometry with mass selective detection (GC-MSD). DAME was the most frequently found (62% of 47 specimens) and often the most abundant target compound, with range and mean ± SD concentrations of < 0.0017 –

• A screening method was developed for chlorinated fungal metabolites.• Drosophilin A methyl ether (DAME) was identified in in fungi and forest litter.• Five fungal species were suggested to produce DAME de novo.• Other chlorinated dimethoxybenzenes were found in some specimens.Fungi and substrates undergoing fungal decomposition were collected from forests in northern and southern Sweden and analyzed for chlorinated dimethoxybenzenes (DMBs).Specimens were fungi fruiting bodies, rotting wood, forest litter and underlying humus.Targeted compounds were DAME (1,2,4,5-tetrachloro-3,6-DMB) and related fungal secondary metabolites.A screening procedure was developed which involved soaking the specimens in ethyl acetate followed by analysis by capillary gas chromatographymass spectrometry with mass selective detection (GC-MSD).DAME was the most frequently found (62% of 47 specimens) and often the most abundant target compound, with range and mean ± SD concentrations of <0.0017-3.81 and 0.21 ± 0.63 mg kg − 1 ww.Based on log-log correlations of partition coefficients of hydrophobic compounds between fungal biomass/water (K D ) and octanol/water (K OW ), five species of fungi are suggested to produce DAME de novo versus bioaccumulation from forest runoff water.Full-scan mass spectra of some high-concentration specimens indicated the presence of a Cl 2 DMB and a Cl 3 DMB, which could not be identified further due to lack of standards, and drosophilin A (DA = 2,3,5,6-tetrachloro-4-methoxyphenol), the precursor to DAME.Tetrachloroveratrole

Introduction
Chlorine in soils is present as the anion (chloride) and covalently bound to organic matter.The organic fraction ranges from 34 to 100% in soils from diverse locations (Svensson et al., 2021).The reported range of total chlorine in forest soils of Sweden is 16-458 mg kg − 1 dry weight, of which two-thirds or more is organically bound; the balance between organic and inorganic chlorine is maintained by rates of chlorination and dechlorination (Svensson et al., 2021(Svensson et al., , 2022)).Chlorination of organic matter takes place most actively in the rhizosphere and is carried out by diverse organisms, including bacteria, fungi and vascular plants, as well as by abiotic processes (Clarke et al., 2006;Montelius et al., 2019;Öberg and Bastviken, 2012;Svensson et al., 2022).
Terrestrial fungi are prolific producers of halogenated secondary metabolites and about 80% of these contain chlorine (Cochereau et al., 2022).The chlorinated compounds in forest soils are diverse, with molecular masses ranging from simple chloromethanes (Wever and Barnett, 2017) to complex compounds such as chlorinated antibiotics and dioxins (Clarke et al., 2006;Winterton, 2000).Basidiomycetes produce chlorinated metabolites during decomposition of forest litter and are also effective at degrading some anthropogenic pollutants.In addition to chloromethanes, basidiomycetes produce chlorinated amino acids, anisyls, benzaldehydes, hydroquinones, anthroquinones, orsinols, sesquiterpenes and others (de Jong and Field, 1997).Some of the lower molecular mass compounds, as well as many nonhalogenated metabolites, have been termed "fungal volatiles" (Dickschat, 2017).
We reported DAME in air and precipitation at stations in Sweden and Finland (Bidleman et al., 2023a) and in rivers and estuaries of the northern Baltic Sea (Bidleman et al., 2023b).In these papers, we also described preliminary observations of DAME in terrestrial fungi from Sweden and suggested their likely role in supplying DAME to the atmosphere, rivers and estuaries.DAME is also widespread in air and surface water across Canada (Zhan et al., 2023) and in the North and South Atlantic Oceans (Schreitmüller and Ballschmiter, 1995).DA was found in wild boar (Sus scrofa) from Germany, presumably from their foraging for mushrooms (Hiebl et al., 2011).
The objectives of this study were to develop a screening method for DAME and similar halomethoxybenzenes (HMBs) in fungi and ground litter and survey these compounds in specimens from Swedish forests.Here we describe analytical methodology for HMBs, report DAME and other chlorinated HMBs in fungi and forest litter, propose a way to distinguish de novo production versus bioconcentration from runoff water and discuss environmental implications.

Sample collection
Sample collection was done during October-November 2021 from forests in Västerbotten and Gävleborg counties in Sweden.The locations are shown on a map in Bidleman et al. (2023b).Specimens collected in brown paper bags were fungal fruiting bodies (sporocarps) and rotting wood, forest litter (conifer needles and deciduous leaves) and underlying humus which were infested with fungal mycelia.Two feather mosses were also included.The paper bags allowed the specimens to "breathe" and prevented moisture buildup.The specimens were refrigerated for several weeks, then transferred to plastic bags and frozen.Identification of fungi and mosses was done at the species level.Descriptions are provided in Table 1.

Extraction and analysis
Different techniques were used to achieve a uniform consistency of samples.Small soft fruiting bodies were extracted whole.Large hard ones were cut into useable pieces with a knife or saw.Portions of fruiting bodies, mosses, rotted wood and forest litter were homogenized with an electric coffee mill.Specimens with a spongy or corky texture were partially frozen, then homogenized.Dry weight (dw) was determined for most samples by oven-drying portions overnight at 70 • C. Table 1 gives the percent dw, which varied greatly from 6 to 7% for two fruiting bodies that were decomposing and in a liquifying state (18F, 24F) to over 80%.Samples of 0.5-3 g wet weight (ww) were transferred to glass culture tubes with polytetrafluorethylene-lined caps.Ethyl acetate (10 mL) was added, the samples were vortexed for 30 s then refrigerated for 3-7 days, agitating periodically.Ethyl acetate is a common solvent for extracting secondary metabolites from fungal mycelia cultures (Riquelme et al., 2020;Silk et al., 2001;Teunissen et al., 1997).

Quality control
Quantification was judged successful when the ratio of quantifying/ qualifying ions was within 20% of values for standards.Several samples showed no peaks for target compounds which were above baseline noise.In these cases, the baseline noise was integrated over the limits of peak elution times and results were expressed as instrumental detection limits (IDL).Averaged over several samples and replicate determinations, this procedure gave limits of detection LOD = mean IDL + 3xSD.LODs were 0.0017 (n = 22), 0.0013 (n = 74), 0.0027 (n = 9) and 0.0022 (n = 42) mg kg − 1 for DAME, TeCV, Cl 2 DMB and Cl 3 DMB, respectively.For statistical evaluations, 1/2 of the LOD was substituted in cases of nondetection (Hites, 2019).In some cases, specimens plus ethyl acetate were spiked with 260 ng 13 C 6 -pentachloroanisole to check recoveries during the extraction process.The mean recovery was 109 ± 4% (n = 16).We did not adjust for recovery.Replicates (n = 2-4) of 29 specimens were analyzed, of which 23 had detectable DAME levels.For these 23, the difference among replicates was 3-41%, with mean ± standard deviation of 14 ± 11%.No difference in DAME concentrations was found for 3-or 7-day extraction times, the 7/3-day ratio averaged 0.99 ± 0.23 (n = 16).

Compound identification
DAME was identified by a retention time which matched that of a standard within 0.02 min and by agreement within 20% between sample and standard ratios of monitored ions within chlorine clusters (259/261, 274/276).Extracts of some higher-concentration specimens were transferred to isooctane, cleaned by shaking for 30 s with 95% sulfuric acid, and full-scan spectra were acquired by GC-MSD (Fig. 1).Spectra of the suspected DAME peak in specimens 9L,16F, 17F and 32F matched the DAME spectrum in the National Institute of Standards and Technology (NIST) library with >90% probability, while the match for specimen 44B was 80%.Drosophilin A (DA), the precursor to DAME (de Jong and Field, 1997), was tentatively identified in 16F and 17F, with a spectrum that matched DA in the NIST library with >90%; however, we    did not have a DA standard for confirmation.Chloroveratroles (CVs) have ortho-positioning of the two methoxy groups.A Cl 3 DMB was tentatively identified by ratios of monitored ions in specimens 9F, 9L,12F,13F,14F,16F,17F,18F, 32F, 44B, 44H, 45B and 46L.Spectral matches with NIST library spectra for 3,4,5-TriCV or its isomer 3,4,6-TriCV in cleaned extracts were 60-90% for 16F, 17F and 32F, and comparisons to our suspected Cl 3 DMB in 16F and 17F are shown in Fig. 1.However, the retention time of the Cl 3 DMB was about 0.1 min later than that of a 3,4,5-TriCV standard, suggesting that our Cl 3 DMB was not this isomer.We did not have a standard of 3,4,6-TriCV, but reported retention times of the two TriCVs on a nonpolar SE-30 column differ by over 2 min, with 3,4,6-TriCV eluting first (Korhonen et al., 1984).Thus, neither 3,4,5-TriCV or 3,4,6-TriCV are likely for our Cl 3 DMB.We have no information about other possible Cl 3 DMBs with different chlorine or methoxy positioning, and prefer the non-specific designation "Cl 3 DMB", since neither TriCV has been reported in fungi.The Cl 3 DMB in our specimens was quantified versus a 3,4,5-TriCV standard.
A Cl 2 DMB was tentatively identified in fewer specimens (9L,12F,14F,16F, 17F, 18F, 32F and 44B) by ratios among monitored ions.Mass spectral matches with chloroneb (1,4-dichloro-2,5-DMB) in the NIST library were 56-72% for 16F, 17F and 32F, and are shown in Fig. 1 for 16F and 17F.However, the purported Cl 2 DMB is not chloroneb because of its much shorter retention time in our specimens (13.0 min versus 16.7 min for a chloroneb standard).A large retention time range, from 12 to 18 min on a nonpolar SE-30 column, has been reported for dichloroveratroles (DiCVs) by Korhonen et al. (1984), but we have no information about DiCVs with other positioning of methoxy groups.The Cl 2 DMB in our specimens was quantified versus chloroneb.
Specimens 16F and 17F were examined by GC-High Resolution Accurate Mass (HRAM) using an Agilent 7250 GC/Q-TOF system (Agilent Technologies, Santa Clara, CA) with the quadrupole in Total Transmission Ion (TTI) mode, and the above J&W DB-5ms Ultra Inert column, operating at a mass resolution of 25,000 FWHM with a TOF accuracy of 2 ppm or better.Exact masses derived from these runs (16F, 17F, respectively) were DAME [M + ] 273.9127,273.9128 (NIST 273.9122 9905,205.9905 (NIST 205.9901 for chloroneb, 1.9 ppm deviation).

Concentrations and distribution of DAME and other compounds
DAME was the most frequently found and often the most abundant chlorinated DMB, above the LOD of 0.0017 mg kg − 1 ww in 29 of 47 specimens of various types (Table 2).
DAME has not previously been reported in mosses, so this finding may appear surprising.However, boreal forest mosses such as Hylocomium splendens and Pleurozium schreberi, are associated with a highly diverse fungal community with taxa of a broad range of life strategies (pathogenic, endophytic, saprotrophic and ectomycorrhizal) (Davey et al., 2017;Kauserud et al., 2008).This may suggest that the occurrence of DAME in the moss samples was from associated fungal mycelia (unidentified) rather than the mosses themselves.
The mean ± SD, median and geometric mean for the set of 47 samples of all types were 0.21 ± 0.63, 0.0038 and 0.0082 mg kg − 1 ww, when nondetectables were replaced by the LOD/2 = 0.00085 mg kg − 1 ww (Section 2.3).The distribution of DAME concentrations is shown in Fig. 3.
T.F.Bidleman et al. tetrachloroveratrole (TeCV = 1,2,3,4-tetrachloro-5,6-dimethoxybenzene).The means ± SD for Cl 3 DMB and Cl 2 DMB in positive samples were 0.058 ± 0.10 mg kg − 1 ww (n = 14) and 0.12 ± 0.19 mg kg − 1 ww (n = 9).Correlations were significant for log Cl 3 DMB with log DAME (r 2 = 0.44, p = 0.0071) and log Cl 2 DMB with log Cl 3 DMB (r 2 = 0.58, p = 0.017) (Fig. 4A and B), while correlation of log Cl 2 DMB with DAME was not significant (r 2 = 0.06, p > 0.05, Fig. 4C).TeCV was infrequently found, in 16F (Thelephora terrestris) at 0.042 mg kg − 1 ww, in moss 44B (Pleurozium schreberi) at 0.11 mg kg − 1 ww, in 38 M (wood infested with Stereum subtomentosum) at 0.033 mg kg − 1 ww and in litter/humus samples at 0.0033-0.016mg kg − 1 ww (n = 3).DAME and TeCV were routinely found in air and precipitation sampled on the Swedish west coast and in Subarctic Finland (Bidleman et al., 2023a(Bidleman et al., , 2023b)).Mean concentrations of DAME and TeCV in air from 2018 to 2019 were 34 ± 23 and 12 ± 7.2 pg m − 3 on the west coast; 41 ± 43 and 2.1 ± 1.5 pg m − 3 in Finland.Concentrations of DAME and TeCV in precipitation in 2018-2019 were 37 ± 30 and 22 ± 18 pg L − 1 on the west coast; 72 ± 57 and 6.4 ± 3.5 pg L − 1 in Finland.Garvie et al. (2015) hypothesized that biomass burning might release DAME to the atmosphere, but no significant correlations were found for airborne DAME or TeCV with combustion markers such as polycyclic aromatic hydrocarbons (PAHs) and benzo[a]pyrene (BaP) in Sweden or Finland (Bidleman et al., 2023a).Also, DAME and TeCV were not correlated with retene (a marker of biomass burning) in Canada (Zhan et al., 2023).However, the Garvie et al. (2015) hypothesis is not necessarily refuted because biomass burning may not be the dominant source of PAHs in the   The source of DAME in air is suspected to be from the terrestrial environment (Bidleman et al., 2023a(Bidleman et al., , 2023b)).TeCV in air might also be of terrestrial origin, but there is only weak evidence in this study of production by fungi fruiting bodies.TeCV was found in forest litter and humus (Table 1), suggesting production in the rhizosphere.Another possible source of TeCV is bacterial O-methylation of the chloroguaiacols produced in bleached Kraft mill effluent (Brownlee et al., 1993;Neilson et al., 1984).TeCV in the atmosphere might be deposited by precipitation (Bidleman et al., 2023a) or scavenged in the forest canopy by sorption to foliage (the "forest filter effect", McLachlan and Horstmann, 1998;Su et al., 2007) and subsequently deposited.TeCV and lower chlorinated veratroles were widespread in air and surface water across Canada (Zhan et al., 2023), and strong correlations between DAME and TeCV in air were found in both Canada (Zhan et al., 2023) and Finland (Bidleman et al., 2023a).However, no evidence of elevated TeCV in the vicinity of pulp and paper production facilities was found in the Zhan et al. (2023) study.These observations suggest natural rather than anthropogenic sources of TeCV.

Production versus bioconcentration
The DAME in forest specimens may be derived from de novo production and by bioconcentration of DAME from waters of various sources: precipitation, canopy throughfall and water flowing through forest ground cover.DAME and DA are also metabolites of the wood preservative pentachlorophenol (Varela et al., 2015;Xiao and Kondo, 2020), although this is not expected to be a contributor in the areas where our specimens were collected.Concentrations of DAME in precipitation collected at Råö on the Swedish west coast (57.39 N, 11.91E) and at Pallas, Finland (68.00 N, 24.23 E) in 2018-2019 averaged 37 and 72 pg L − 1 respectively (Bidleman et al., 2023a), while higher levels were found in rivers of Västerbotten County, averaging 307 pg L − 1 in 2017-2022, presumably due to the contribution from terrestrial runoff (Bidleman et al., 2023b).
To assess whether levels of DAME in the various specimens were likely from de novo production or bioconcentration, we sought a relationship between the fungi/water distribution coefficient (K D , L kg − 1 = fungi (mg kg − 1 )/water (mg L − 1 ) and the octanol-water (K OW ) distribution coefficient of hydrophobic organic compounds.Eleven such studies are summarized in Tables 3 and 4, and Fig. 5, in which fungal biomass was equilibrated with aqueous solutions of polycyclic aromatic hydrocarbons (PAHs), pesticides, chlorobenzene or a polychlorinated biphenyl.We did not include reports for ionizable phenolic compounds (e.g., phenol, chlorophenols) because even though DAME is derived from a chlorinated methoxyphenol (DA), it is a neutral compound.The K D in each case was taken from reported literature values or calculated from the reported Freundlich sorption parameters, and for all compounds in Table 4 followed the relationship with r 2 = 0.664 (Fig. 5): (1) Fig. 3. Distribution of DAME concentrations in 47 specimens of various types (Table 2).K OW is not known for DAME, but log K OW for TeCV (an isomer of DAME) is 4.86 at 25 • C (Lun et al., 1995).Assuming this log K OW also applies to DAME, the predicted value of log K D /L kg − 1 is 4.39 with a 95% confidence interval of 3.47-5.32(Fig. 5).The central value and (95% prediction range) for K D = 2.45 x10 4 (2.95 x 10 3 -2.09x 10 5 ) L kg − 1 .The average concentration (C W ) of DAME in Västerbotten rivers in 2017-2022 was 307 pg L − 1 (3.07 x 10 − 7 mg L − 1 ), which we assume came from terrestrial runoff (Bidleman et al., 2023b).This assumption is open to question, because water in rivers comes not only from surface runoff but also groundwater flow (Laudon and Sponseller, 2017).However, we have no information on DAME in groundwater.The predicted lower and upper concentrations of DAME in fungi in equilibrium with the above water concentration are K D *C W = 2.95 x 10 3 L kg − 1 x 3.07 x 10 − 7 mg L − 1 = 0.0009 mg kg − 1, and 2.09 x 10 5 L kg − 1 x 3.07 x 10 − 7 mg L − 1 = 0.064 mg kg − 1 .
The upper end of this 95% prediction range, viz.0.064 mg kg − 1 , appears to be a reasonable dividing point in this study to judge de novo production versus bioconcentration.According to this criterion, a few basidiomycetes in Table 2 may be DAME producers, viz.Micromphale perforans (9F), Stereum hirsutum (12F), Thelephora terrestris (16F), Stereum subtomentosum (38 M) and Hydnellum mirabile (17F).However, the only reliable way to confirm this would be to culture these species in the laboratory and test them for DAME synthesis.Teunissen et al. (1997) screened 92 basidiomycetes strains in laboratory cultures and found only five that produced DAME.

The role of chlorine availability
Species reported to produce DAME are Agaricus bisporus, Agaricus arvensis, Bjerkandera adusta, Hypholoma fasciculare, Mycena megaspore, Peniophora pseudeopini, Phellinus fastuosus, Phellinus robineae, Phellinus yucatensis (de Jong and Field, 1997;Teunissen et al., 1997), Phellinus badius (Garvie et al., 2015) and Phylloporia boldo (Riquelme et al., 2020).It is curious that the above Phellinus species produce DAME in high concentrations, ranging from 70 to 24000 mg kg − 1 (de Jong and Field, 1997;Garvie et al., 2015;Teunissen et al., 1997), whereas the species examined by us (5F, 28F, 35F) contained DAME levels that were barely above detection or not detectable.In the case of Phellinus badius, the DAME was coincident with very high concentrations of chlorine, 22, 000-28,000 mg kg − 1 in fresh basidiocarps and 4800 mg kg − 1 in decaying mesquite heartwood (Garvie et al., 2015).Chlorine in wood and bark of four summer-harvested tree species in Finland was much lower, ranging from 30 to 330 mg kg − 1 , while the chlorine content of different parts of the same tree (wood, bark, shoots, foliage) ranged up to 1090 mg kg − 1 (Werkelin et al., 2005(Werkelin et al., , 2011)).Of the five basidiomycetes found to produce DAME by Teunissen et al. (1997), production in culture media by four species ranged from 138 to 1380 mg L− 1 while the range for Phellinus fastusosus was 1100-11,000 mg L − 1 .The culture media used by Teunissen et al. (1997) contained 58 mg L − 1 NaCl, within the chloride range of Swedish soils (Svensson et al., 2011(Svensson et al., , 2021)).Riquelme et al. (2020) observed an increase in production of DAME, DA and chloroneb by Phylloporia boldo upon addition of KCl to culture medium.It may be that production of DAME and other chlorinated fungal metabolites is chlorine-limited in our study areas.Such availability could be influenced by the atmospheric deposition of chlorine and its biogeochemical cycle in specific microenvironments (Svensson et al., 2021), factors that should be considered in future investigations.

Limitations of the study
The ability to identify HMBs is hampered by lack of analytical standards.Standards for DAME and some of the chloroveratroles are available commercially, but HMBs with other positioning of methoxy groups are not, and workers in previous studies often synthesized their own.Assessment of production versus bioconcentration (Section 3.2) is uncertain due to limited knowledge concerning sorption of HMBs by fungi.Studies reported in Tables 3 and 4 were done with other compounds and were conducted with fungi that received harsh pretreatment before use.Experiments of biosorption of HMBs by fungi under realistic field exposure conditions are needed.Although our survey included more fungi for HMBs than in most other studies, those in Tables 1 and 2 represent only about 1% of the fungi species that have been identified in Sweden (approximately 2700, https://svamparisverige.se/start/a   bout/).The possible influence of chlorine availability should be considered in future investigations (Section 3.3).

Environmental significance
DAME is globally distributed in the atmosphere (Bidleman et al., 2023a(Bidleman et al., , 2023b;;Schreitmüller and Ballschmiter, 1995;Zhan et al., 2023) and enters northern Baltic estuaries by terrestrial runoff (Bidleman et al., 2023b).Atmospheric deposition of airborne DAME may also contribute to coastal and offshore waters (Bidleman et al., 2023b;Zhan et al., 2023).This study provides evidence of forest fungi and litter as sources of DAME and possibly other chlorinated DMBs in streams, and it is likely that input comes from fungi in non-forested regimes as well.Bioaccumulation by fish has been shown for DAME (Fernando et al., 2018;Renaguli et al., 2020), TriCV and TeCV (Neilson et al., 1984).Predictions from structure-activity relationships suggest some toxic properties for DAME (Zhan et al., 2023).Threshold toxic concentrations to zebra fish (Brachydanio rerio) embryos and larvae have been determined for TriCV, TeCV, pentachloroanisole and a trichlorotrimethoxybenzene (Neilson et al., 1984).

Conclusions
This study supports our hypothesis of fungi as a source of DAME in terrestrial runoff and indicates that other chlorinated secondary metabolites are present as well.Five fungal species may be heretofor unidentified producers of DAME and its precursor DA was found in two of them.The simple procedure presented here of soak-extraction followed by GC-MSD is suitable for screening DAME and related compounds in fungi and forest litter.We suggest fruitful extensions of this work on several fronts: laboratory experiments to verify production by candidate species, field studies to extend the survey and examine spatial and temporal variability, biosorption experiments by fungi and forest litter to determine partitioning with runoff water.Considering the global spread of DAME, it would be good to have a better understanding of its sources and pathways, as a terrestrial marker and availability for bioaccumulation.

Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Fig. 1A .
Fig. 1A.Top: Chromatograms of specimens 16F and 17F, showing DAME, drosophilin A (DA), and structurally unidentified compounds Cl 2 DMB and Cl 3 DMB.The middle two panels show mass spectra of the Cl 2 DMB peak and the spectral match with the NIST library for chloroneb, while the bottom two panels show mass spectra of the Cl 3 DMB peak and the spectral match with the NIST library for 3,4,6-TriCV or 3,4,5-TriCV.However, Cl 2 DMB and Cl 3 DMB are not likely to be these NIST compounds, but may be isomeric with them, for reasons explained in the text.

Fig. 1b .
Fig. 1b.Top: Chromatograms of specimens 16F and 17F, showing DAME, drosophilin A (DA), and structurally unidentified compounds Cl 2 DMB and Cl 3 DMB.The middle two panels show mass spectra of the DAME peak and the spectral match with the NIST library for DAME, while the bottom two panels show mass spectra of the DA peak and the spectral match with the NIST library for DA.

Fig. 5 .
Fig. 5. Relationship between the fungi/water (K D , L kg − 1 ) and octanol-water (K OW ) distribution coefficients for the compounds in Table2, with mean and predicted 95% confidence intervals shown by the curved dotted and solid lines, respectively.Log K D = 1.0974*logK OW -0.9405, r 2 = 0.664.The mean log K D = 4.39 at the assumed DAME K OW = 4.86 with a predicted 95% confidence interval of 3.47-5.32(orange arrow).

Table 2
Chlorodimethoxybenzenes in specimens from Swedish forests.a

Table 3
Studies of sorption to fungal biomass.

Table 4
Distribution coefficients between fungi a and water, K D , L kg -1 and octanol-water, K OW .