Pahs In Estonia

ENVIRONMENTAL POLLUTION

Environmental Pollution 105 (1999) 67±74

Polycyclic aromatic hydrocarbons in Estonian soil: contamination and pro®les M. Trapido* Department of Environmental Chemistry and Technology, Institute of Chemistry at Tallinn Technical University; 15, Akadeemia tee, 12618, Tallinn, Estonia Received 27 April 1998; accepted 12 November 1998

Abstract The distribution and accumulation of polycyclic aromatic hydrocarbons (PAH) in soil as well as PAH pro®les have been investigated in areas with di€erent anthropogenic pollution such as the city of Tallinn, the towns of PaÈrnu and Kohtla-JaÈrve and some rural areas. PAH were identi®ed in 147 soil samples (0±10 cm upper layer) collected in September 1996. The typical  PAH level in Estonian rural soil is about 100 mg/kg dry weight. PAH concentrations in Tallinn, PaÈrnu and Kohtla-JaÈrve soil were quite high (the mean  PAH concentrations were 2240, 7665 and 12 390 mg/kg dry weight, respectively). The dominant PAH in soil samples were pyrene, triphenylene and ¯uoranthene. 3±4 ring PAH and 5±6 ring PAH ratio altered from 5:1 to 1.7:1. # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Polycyclic aromatic hydrocarbons (PAH); Contamination; Pro®les; Soil; Estonia

1. Introduction Polycyclic aromatic hydrocarbons (PAH) released into the environment arise mainly from anthropogenic sources. They are mainly formed as by-products of incomplete combustion of organic materials. PAH have been identi®ed in many emission sources, such as vehicle exhausts, power plants, chemical-, coke- and oil-shale industries, urban sewage. Primary natural sources of PAH are forest ®res and volcanic activity (Suess, 1976; Shabad and Ilnitskii, 1979). United States Environmental Protection Agency (US EPA) has identi®ed 16 PAHs as `priority pollutants'. PAH are important environmentally because many individual PAH are genotoxic (White et al., 1998) and may cause mutations and certain types of cancer. PAH compounds convert into carcinogens through metabolic activation in the organism. In many circumstances the environmental occurrence of PAH has been associated with adverse e€ects on public health (Yang et al., 1991). PAH are quite resistant to degradation. The range of half-lives for PAH in soil estimated by di€erent researchers is quite large. They vary, dependent on the * Tel.: +372-2536-269; e-mail: [email protected].

compound, from 2 month to 2 years (Mackay et al., 1992) and from 8 to 28 years (Wild et al., 1990). When the release of PAH into the environment exceeds their degradation capacity, a signi®cant accumulation of PAH is observed. The existence of permanent pollution sources results in the accumulation of PAH in soil, plants and water bodies. Soil contamination originates mainly from PAH emissions to the atmosphere, which reach the soil via precipitation. Gaseous and particle-bound PAH can be transported over long distances before deposition (Wania and Mackay, 1996). PAH are accumulated mainly in the humus layer of soil. The further pathways of PAH dissipation in contaminated soil may be volatilisation, irreversible sorption, leaching, accumulation by plants, and biodegradation (Reilley et al., 1996). PAH with three and more rings tend to be strongly adsorbed to the soil. Strong sorption coupled with very low water solubility and very low vapour pressures make leaching and volatilisation insigni®cant pathway of PAH dissipation (Park et al., 1990). Also plants hardly take up any PAH from soil (Shabad and Ilnitskii, 1979; Sims and Overcash, 1983). Soil bacteria are the primary degraders of PAH in soil (Shabad and Ilnitskii, 1979, Gibson and Subramanian, 1984; Boldrin et al., 1993).

0269-7491/99/$Ðsee front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0269 -7 491(98)00207 -3

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PAH concentration in soil correlates signi®cantly with the corresponding levels in air (Vogt et al., 1987), house dust (Chuang et al., 1995), urban street dust (Takada et al., 1990) and plants (Wang and Meresz, 1982), therefore, PAH determination in soil may provide important information on the environmental pollution state. Characteristic ratio of PAH and PAH pro®les can be used in qualitative and quantitative source estimation (Vogt et al., 1987; Yang et al., 1991). The concentrations and distribution of PAH in Estonia have been studied mainly in water, bottom sediments, ®sh, etc. (Veldre et al., 1979, 1987; Yegorov et al., 1989; Trapido and Palm, 1991; Trapido et al., 1992). No studies have been carried out to assess the accumulation and distribution of PAH in soil. The main aims of the present study were to assess soil contamination by PAH in Estonia, to relate PAH compound pro®les to di€erent types of anthropogenic input and to determine the regional background PAH levels in soil. 2. Material and methods 2.1. Sampling The concentrations of PAH in soil and PAH pro®les were determined in Tallinn, PaÈrnu, Kohtla-JaÈrve, and in the rural areas: Harjumaa, PaÈrnumaa, and Ida-Virumaa.

The data from the rural areas were used for the estimation of the PAH soil background concentrations in Estonia. The sampling areas are shown in Fig. 1 and characterised in Table 1. A total of 133 soil samples (68 rural and 65 urban areas) were collected and analysed. Soil samples (0±10 cm upper layer) were collected in September 1996 according to Aamot et al. (1987, 1996). The samples were collected at least 25 m away from roads in the urban areas and at least 150 m from the roadside in the rural ones. Samples were not collected from known contaminated sites as the territory of power stations and industrial enterprises, etc. 2.2. Analysis The samples were dried at room temperature for 2 days, then at 50 C for 2±3 hours, sieved through a 2-mm mesh to remove large particles and organic debris, and stored at 5 C prior to analysis. Twenty grams of dry sample were soaked in 75 ml of hexane (analytical grade, puri®ed additionally with activated carbon) overnight. The ultrasonic extraction procedure twice during 5 minutes followed (sonicator UZDA-A, Nauchpribor, USSR, operated at 22‹1.65 kHz; power input was 80 W). The second extraction was conducted with 50 ml of hexane. The recovery of PAH from soil obtained using ultrasonic extraction was comparable to recovery obtained with

Fig. 1. Location of sampling sites for the present study.

M. Trapido / Environmental Pollution 105 (1999) 67±74

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Table 1 The sampling sites and the description of the area Site no.

Sampling area (number of samples)

Description of area and presupposed PAH sources

1 2 3 4

Tallinn (34) Tallinn, centre (7) PaÈrnu (16) Kohtla-JaÈrve (15)

5 6 7 8

Maardu (16) Harjumaa (37) PaÈrnumaa (38) Ida-Virumaa (7)

The capital of Estonia, 420 500a inhabitants, heavy trac, industry and heating Extremely heavy trac, domestic heating Health resort, 51 800a inhabitants, trac, domestic heating Industrial area, 53 500a inhabitants, oil-shale thermal treatment industry (KIVITER), chemical industry, power station, trac Rural, 20 000a inhabitants, harbour, phosphorite mining (until 1990), trac Rural, 77 974a inhabitants Rural, 34 800a inhabitants Rural, 22 100a inhabitants, oil-shale mining

a

According to Statistical Yearbook of Estonia, 1997.

Soxhlet extraction (Golden and Sawicki, 1975; Trapido, 1995). Combined hexane extracts were evaporated carefully to the volume of about 1 ml and then fractionated by the thin-layer chromatography with aluminium oxide (TLC grade, Reanal, Hungary). The mobile phase was hexane±benzene 4:1 (by volume). PAH fraction was eluted using twice 5 ml of acetone (extra pure grade, Reachim, Russia). Acetone was evaporated dry at room temperature and the residue was dissolved in 0.22.0 ml of acetone (dependent to PAH concentration). Measurement of PAH concentration was carried out with high performance liquid chromatography (HPLC; model 1311, Minsk, Byelorussia). The eluting solvent was a mixture of acetonitrile-water (both HPLC grade) 93:7 (by volume) with ¯ow rate 8 ml minÿ1. Fluorescence detection with initiation wavelength 254 and 298 nm, the range of registration 330±600 nm was used. Chromatographic column (0.5300 mm) was ®lled with Silosorb C18 (Chemapol, Czechoslovakia). The coecient of variation for HPLC method was 1.5%. PAH standards were obtained from Aldrich Chemical Company. Twelve PAH have been quanti®ed in the samples: phenanthrene (Ph), anthracene (A), ¯uoranthene (Fl), pyrene (P), triphenylene (TPh), benzo(a)anthracene (BaA), chrysene (Chr), benzo(e)pyrene+benzo(b)¯uoranthene (BeP), benzo(k)¯uoranthene (BkFl), benzo(a)pyrene (BaP), and benzo(ghi)perylene (BghiPer).  PAH refers to the sum of these 12 compounds. The procedure described earlier has been checked for recovery eciencies by analyzing soil samples spiked with PAH standards. Recovery of PAH was in 86±98% range. Replicate analyses gave an error of ‹10%. 3. Results and discussion 3.1. PAH concentrations The mean and standard deviations of PAH concentrations in soil in di€erent sampling areas are listed in Table 2. The  PAH values ranged over 4 orders of

magnitude from 11.2 to 153 000 mg/kg. Signi®cant differences (at least one order of magnitude) were observed in  PAH concentrations between rural and urban areas (see Fig. 2). PAH concentrations in soil in Tallinn also varied to a great extent at di€erent sampling points. The  PAH concentration for Tallinn ranged from 35.5 to maximum 26 300 mg/kg. PAH concentrations were signi®cantly higher in the central part of the city probably due to intense trac (average value 9015‹6363 mg/kg dry weight) than in the other parts of the city (compare data from Table 2). The investigation of snow cover PAH pollution also indicated enhanced PAH level in the centre of Tallinn compared to the remote sites of the city (Trapido et al., 1992). PAH concentration in soil decreases with increasing distance from the centre of the city. The decrease of  PAH in north-east direction is presented in Fig. 3 as a typical example. It declines to the remote level (200 mg/kg or less) by the outskirts of the city (8±10 km from the centre). Transport became the predominant source of environmental pollution in the city of Tallinn during recent 5±6 years contributing up to 90% of air pollution of the city (Statistical Yearbook of Estonia, 1997). The amount of cars has doubled during this period, that is a unique rate all over the world. As the transport system is overloaded, frequent (in some locations close to permanent) trac jams appear in the centre of the city. At the same time air pollution load from stationary sources declined three times due to economical situation (more than 50% falling-o€ of production). Therefore, trac could be one of the main reasons for enhanced PAH concentrations in soil in the centre of the city. The average PAH concentrations in soil were quite high in two other cities Ð PaÈrnu and Kohtla-JaÈrve. For the latter it has been expected, as Kohtla-JaÈrve is an industrial town (oil-shale thermal treatment, etc.) and probably the most polluted town in Estonia. High concentrations of PAH in PaÈrnu (average value 7665 ‹4306 mg/kg dry weight) were unexpected as PaÈrnu is a health resort with minor industrial emissions into the

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Table 2 The mean concentrations and standard deviations of PAH in soil, mg/kg dry weight PAH

Ph A Fl P TPh BaA Chr BeP BkFl BaP BghiPer  PAH (3±4 ring)  PAH (>5 ring)  PAH Number of samples

Sampling area (site no.) Tallinn (No. 1)

Tallinn, centre (No. 2)

PaÈrnu (No. 3)

Kohtla-JaÈrve (No. 4)

Maardu (No. 5)

Harjumaa (No. 6)

PaÈrnumaa (No 7)

Ida-Virumaa (No 8)

160‹67 15‹4 481‹159 227‹138 662‹459 131‹81 148‹84 76‹69 43‹40 106‹60 110‹101 1890‹980 351‹150 2200‹1396 34

680‹628 69‹53 2150‹1250 762‹550 2860‹1900 536‹382 600‹420 289‹161 162‹125 398‹182 359‹246 7755‹5910 1260‹533 9015‹6363 7

292‹230 49‹24 1090‹810 795‹490 2540‹1710 443‹332 507‹420 380‹255 198‹79 1113‹313 233‹196 5720‹3440 1945‹922 7665‹4306 16

161‹116 23‹13 769‹563 2850‹2278 2675‹1607 516‹426 876‹730 904‹820 402‹363 1224‹1090 1996‹1865 7870‹5680 4517‹4140 12390‹9810 15

18‹8 1.0‹0.8 22‹16 68‹34 60‹40 10‹6 14‹10 8.5‹7.3 4.4‹3.8 6.8‹5.1 25‹23 188‹103 45‹35 233‹185 16

21‹13 0.8‹0.6 23‹19 51‹44 52‹29 12‹4.6 15‹9 12‹5.9 5.6‹3.3 15‹9 20‹18 175‹88 57.5‹29 232‹153 37

48‹17 2.9‹1.2 72‹46 142‹98 167‹144 22‹15 34‹20 25‹16 12‹6 27‹14 27‹18 488‹390 96‹90 584‹379 8

61‹45 2.9‹2.1 44‹24 211‹177 218‹156 47‹26 67‹41 31‹17 4.5‹2.5 31‹23 51‹30 652‹485 118‹80 770‹595 7

PAH, polycyclic aromatic hydrocarbons; phenanthrene, Ph; anthracene, A; ¯uoranthene, Fl; pyrene, P; triphenylene, TPh; benzo(a)anthracene, BaA; chrysene, Chr; benzo(e)pyrene+benzo(b)¯uoranthene, BeP; benzo(k)¯uoranthene, BkFl; benzo(a)pyrene, BaP; and benzo(ghi)perylene, BghiPer.

Fig. 2. Polycyclic aromatic hydrocarbons (PAH) in soil in di€erent sampling areas. Numbers of sampling areas correspond to those in Table 1.

atmosphere. The individual domestic heating (mainly based on wood, coal and peat) is widely used in PaÈrnu. Trac is also quite intensive in the central part of the town making its contribution to soil PAH concentrations. These two important sources of PAH are likely to be responsible for high PAH concentration in soil in PaÈrnu. PAH concentrations also showed, in general, the tendency to decrease in direction from the centre of PaÈrnu to the outskirts. The study of soil pollution in the town of KohtlaJaÈrve indicated very high soil PAH pollution level. An average  PAH concentration in soil in Kohtla-JaÈrve (12 390‹9810 mg/kg dry weight) was higher than the corresponding data from other sampling areas. The in¯uence of the industrial enterprises on the soil PAH pollution was quite clear. The average  PAH in soil

Fig. 3.  PAH in soil at various distances from the centre of the city of Tallinn (north-east direction).  PAH, sum of the compounds; phenanthrene, Ph; anthracene, A; ¯uoranthene, Fl; pyrene, P; triphenylene, TPh; benzo(a)anthracene, BaA; chrysene, Chr; benzo(e)pyrene+benzo(b)¯uoranthene, BeP; benzo(k)¯uoranthene, BkFl; benzo(a) pyrene, BaP; and benzo(ghi)perylene, BghiPer.

near the industrial area was twice that in the residential one.  PAH in 27% of soil samples in Kohtla-JaÈrve exceeded 4000 mg/kgÐthe intervention value for soil sanitation set by the Dutch government (Van Brummelen et al., 1996). These results are quite reasonable and expected, as oil-shale thermal treatment industry situated in Kohtla-JaÈrve is known as an important PAH pollution source (Shabad and Ilnitskii, 1979; Veldre et al., 1979). Moreover, the highly industrialised north-east is estimated as one of the most polluted areas in Estonia. The average PAH concentrations in PaÈrnu, KohtlaJaÈrve and also at the central part of Tallinn were higher

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than those reported for the areas contaminated by aluminium plant (Vogt et al., 1987), by blast furnace plant (Van Brummelen et al., 1996) and in soil samples collected 0.5 m from the roadway (Yang et al., 1991). In 23.4% of soils sampled in the urban areas (see Fig. 4)  PAH exceeded 4000 mg/kg. The data in Table 2 indicates that the average PAH concentration in the cities was at least one order of magnitude higher than in rural areas. PAH concentrations in three rural areas (PaÈrnumaa, Harjumaa and Ida-Virumaa) varied from 11.2 to 2240 mg/kg. The lowest value was determined in Harjumaa and the highest in Ida-Virumaa. The latter demonstrates that PAH pollution level is enhanced not only in the town of Kohtla-JaÈrve, but also in the surrounding rural area of Ida-Virumaa. The data for soil PAH from Maardu were treated separately from the data from the rest Harjumaa, as there are some di€erences in the human activities in Maardu and the rest of Harjumaa (see Table 1), and therefore some di€erences in soil PAH could be expected. The analysis of the data showed that there were no di€erences in concentrations or in the

71

PAH pattern. The mean  PAH concentrations were higher in PaÈrnumaa and Ida-Virumaa than in Harjumaa. Typical soil  PAH concentration derived from samples from rural areas is estimated at about 100 mg/ kg dry weight. This concentration is typical in the areas where no anthropogenic pollution sources occur. In this study 40.3% of soils sampled in the rural areas have  PAH concentration less than 100 mg/kg (see Fig. 4). As it has been suggested (Shabad and Ilnitskii, 1979; Edwards, 1983) that the typical endogenous  PAH in soil, resulting from plant synthesis and natural ®res, is in the range of 1±10 mg/kg. It can be concluded that typical Estonian soils from rural areas are contaminated with PAH above the natural level. This may be due to long-range atmospheric transport of PAH from source regions to these remote sites. Taking into account that the climate conditions in Estonia are unfavourable for PAH degradation in soil during substantial part of the year due to low bacterial activity, it can be assumed that typical soil PAH level is di€erent when compared with soils in other climates. Therefore, the typical soil PAH typical level in Estonia can only be compared with the data from other northern countries.  PAH from Estonian rural areas is signi®cantly lower than in south Norway, similar to rural areas in Wales and twice that in central Norway (Jones et al., 1989; Aamot et al., 1996). The typical  PAH levels in Estonia were higher than the target value set by Dutch government for unpolluted soil (20±50 mg/kg dry weight; Van Brummelen et al., 1996). This target value was reached in less than 10% of all samples from Estonian rural areas. 3.2. PAH pro®les

Fig. 4. The distribution of (PAH concentrations in the rural and urban areas. phenanthrene, Ph; anthracene, A; ¯uoranthene, Fl; pyrene, P; triphenylene, TPh; benzo(a)anthracene, BaA; chrysene, Chr; benzo(e)pyrene+benzo(b)¯uoranthene, BeP; benzo(k)¯uoranthene, BkFl; benzo(a)pyrene, BaP; and benzo(ghi)perylene, BghiPer.

Fig. 5 presents bar diagrams of PAH as normalised average concentrations in soil for eight sampling areas. The main relative proportions appear to be quite constant. Nevertheless, the bar diagrams indicate that the samples from di€erent sampling sites still have di€erent patterns. The three dominant PAH found in soil are pyrene, triphenylene and ¯uoranthene in all areas under study. They formed 8±30, 18±35 and 5±25% of the  PAH, respectively. 3±4 ring PAH dominate in all samples. The ratio of the 3±4 ring PAH to that of 5±6 ring PAH ratio varied from 5:1 (in Tallinn and PaÈrnumaa) to 1.7:1 (in Kohtla-JaÈrve and Ida-Virumaa). PAH pro®les in all rural areas are quite similar. The bar diagrams (Fig. 5) show that the samples from the rural areas have a di€erent PAH pro®le from the soil samples collected in towns. There are certain di€erences in PAH pro®les in soil samples from di€erent towns. In general, PAH pro®les in Tallinn and PaÈrnu are quite similar. Still, soil samples from PaÈrnu contain relatively high concentrations of benzo(a)pyrene. Soil from Tallinn

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M. Trapido / Environmental Pollution 105 (1999) 67±74

Fig. 5. Bar diagram of normalised average polycyclic aromatic hydrocarbons (PAH) concentrations in soil in di€erent sampling areas. Normalisation has been done by dividing the average concentration for each PAH by the concentration pyrene (P) in each separate sampling site. PAH: 1, phenanthrene; 2, anthracene; 3, ¯uoranthene; 4, pyrene; 5, triphenylene; 6, benzo(a)anthracene; 7, chrysene; 8, benzo(e)pyrene+benzo(b)¯uoranthene; 9, benzo(k)¯uoranthene; 10, benzo(a)pyrene; 11, benzo(ghi) perylene.

has enhanced amount of phenanthrene. PAH pro®le in Kohtla-JaÈrve is di€erent from that in Tallinn and PaÈrnu, and similar to soil PAH pro®le in rural areas.

The important characteristic feature of PAH pro®le in Kohtla-JaÈrve is relatively high concentration of benzo (ghi)perylene.

M. Trapido / Environmental Pollution 105 (1999) 67±74

The PAH pro®les have a great importance from the point of view of potential health e€ects. The samples from Kohtla-JaÈrve contain relatively high concentrations of heavy PAHÐbenzo(ghi)perylene and benzo(a) pyrene. Benzo(a)pyrene forms 7±18% of  PAH in soil samples from PaÈrnu, whilst at the other areas it varies from 2.9 to 6.5% of the total PAH content. In both, PaÈrnu and Kohtla-JaÈrve, the soil samples are polluted with relatively high amount of heavy PAH that are known to be carcinogenic (have sucient evidence of carcinogenicity in experimental animals) according to the estimation of the International Agency for Research on Cancer (1983). 4. Conclusions The investigation on the PAH accumulation in soil showed that Estonian soils are polluted by PAH above the natural level. PAH concentrations in soil varied from 11.2 to 153 000 mg/kg dry weight. In the cities, soil PAH concentrations were quite high. The most PAH contaminated soil was in Kohtla-JaÈrve. The average PAH concentration in the cities was at least one order of magnitude higher than in the rural areas. The typical  PAH concentration in Estonia may be estimated as 100 mg/kg dry weight, that is higher than the corresponding data from some northern countries. The three dominant PAH in soil in all sampling areas were found to be pyrene, triphenylene and ¯uoranthene. Still, the PAH pattern varied in di€erent sampling areas. Acknowledgements The investigation was supported by Estonian Science Foundation (Grant 2701). The author is deeply grateful to Mr Heikki Junninen for technical assistance and to Dr Lidiya Bityukova for her valuable suggestions and kind help in sampling. Suggestions by two anonymous referees are gratefully acknowledged.

References Aamot, E., Krane, J., Steinnes, E., 1987. Determination of trace amounts of polycyclic aromatic hydrocarbons in soil. Fresenius Zeitschruft fuÈr Analytische Chemie 328, 569±571. Aamot, E., Steinnes, E., Schmid, R., 1996. Polycyclic aromatic hydrocarbons in Norwegian forest soil: impact of long range atmospheric transport. Environmental Pollution 92, 275±280. Boldrin, B., Tiehm, A., Fritzsche, C., 1993. Degradation of phenanthrene, ¯uorene, ¯uoranthene, and pyrene by Mycobacterium sp. Applied Environmental Microbiology 59, 1927±1930. Chuang, J.C., Callahan, P.J., Menton, R.G., Gordon, C.M., 1995. Monitoring methods for polycyclic aromatic hydrocarbons and their distribution in house dust and track-in soil. Environmental Science and Technology 29, 494±500.

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Edwards, N.T.J., 1983. Polycyclic aromatic hydrocarbons (PAHs) in the terrestrial environmentÐa review. Journal of Environmental Quality 12, 427±441. Gibson, D.T., Subramanian, V., 1984. Microbial degradation of aromatic hydrocarbons. In: Gibson, D.T. (Ed.), Microbial Degradation of Organic Compounds. Marcel Dekker, New York, pp. 181±252. Golden, C., Sawicki, E., 1975. Ultrasonic extraction of total particulate aromatic hydrocarbons from airborne particulates at room temperature. International Journal of Environmental Analytical Chemistry 4, 9±23. Jones, K.C., Stratford, J.A., Waterhouse, K.S., Vogt, N.B., 1989. Organic contaminants in Welsh soils: polycyclic aromatic hydrocarbons. Environmental Science and Technology 23, 540±550. International Agency for Research on Cancer, 1983. Polynuclear Aromatic Compounds. Part I, Chemical, Environmental and Experimental Data. World Health Organization, Lyon, France. Mackay, D., Shui, W.Y., Ma, K.C., 1992. Illustated Handbook of Physical-Chemical Properties and Environmental Fate of Organic Chemicals. Lewis, Boca Raton, FL. Park, K.S., Sims, R.S., Dupont, R.R., Doucette, W.J., Mathews, J.E., 1990. Fate of polycyclic aromatic hydrocarbon compounds in two soil types: in¯uence of volatilisation, abiotic loss and biological activity. Environmental Toxicology and Chemistry 9, 187±195. Reilley, K.A., Banks, M.K., Schwab, A.P., 1996. Dissipation of polycyclic aromatic hydrocarbons in the rhizosphere. Journal of Environmental Quality 25, 212±219. Shabad, L.M., Ilnitskii, A.P., 1979. Carcinogens in the Human Environment. SzabvanykidoÂ, Budapest. Sims, R.S., Overcash, M.R., 1983. Fate of polynuclear compounds (PNAs) in soilÐplant system. Residue Review 88, 1±68. Statistical Yearbook of Estonia, 1997. Tallinn, pp. 52±77. Suess, M.J., 1976. The environmental load and cycle of polycyclic aromatic hydrocarbons. Science of the Total Environment 6, 239± 250. Takada, H., Onda, T., Ogura, N., 1990. Determination of polycyclic aromatic hydrocarbons in urban street dust and their source material by capillary gas chromatography. Environmental Science and Technology 24, 1179±1186. Trapido, M., 1995. Microcolumn high-performance liquid chromatography for analysis of environmental pollutants: polyaromatic hydrocarbons; phenols. Tartu University. Publications on Chemistry. Extended Abstracts of the Symposium Environmental Analyze 23, 177±180. Trapido, M., Palm, T., 1991. A study of the content and convertibility of polycyclic aromatic hydrocarbons (PAH) and sulfur in lichen Hypogymnia physodes and its substrate. Proceedings of the Estonian Academy of Sciences and Biology 1, 7276. Trapido, M., Rajur, K., Yegorov, D., 1992. Investigation of microcomponents in the snow cover in Tallinn. Proceedings of the Estonian Academy of Sciences and Ecology 2, 174±180. Van Brummelen, T.C., Verweij, R.A., Wedzinga, S.A., Van Gestel, C.A.M., 1996. Enrichment of polycyclic aromatic hydrocarbons in forest soil near a blast furnace plant. Chemosphere 32, 293±314. Veldre, I.A., Itra, A.R., Paalme, L.P., 1979. Levels of benzo(a)pyrene in oil shale industry wastes, some water bodies of water in the Estonian S.S.R. and in water organisms. Environmental Health Perspectives 30, 211±216. Veldre, I.A., Itra, A.R., Wettig, K., 1987. Pro®le polyzyklischer aromatischer Kohlenwassersto€e in GewaÈssern der Estnischen SSR. Arch. Geschwulstforsch 57, 373±378. Vogt, N.B., Brakstad, F., Thrane, K., Nordenson, S., Krane, J., Aamot, E., Kolset, K., Esbensen, K., Steinnes, E., 1987. Polycyclic aromatic hydrocarbons in soil and air: statistical analysis and classi®cation by the SIMCA method. Environmental Science and Technology 21, 35±44. Wang, D.T., Meresz, O., 1982. Occurrence and potential uptake of polynuclear aromatic hydrocarbons of highway trac origin by

74

M. Trapido / Environmental Pollution 105 (1999) 67±74

proximal grown food crops. In: Cooke, M., Dennis, A.J. (Eds.), Polynuclear Aromatic Hydrocarbons: Physical and Biological Chemistry. Batelle Press, Columbus, N.-Y., pp. 885±896. Wania, F., Mackay, D., 1996. Tracking the distribution of persistent organic pollutants. Environmental Science and Technology 30, 390A±396A. White, P.A., Rasmussen, J.B., Blaise, C., 1998. Genotoxic substances in the St. Lawrence system I: industrial genotoxins sorbed to particulate matter in the St. Lawrence, St. Maurice and Saguenay Rivers, Canada. Environ. Toxicological Chemistry 17, 286±303. 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: polycyclic aromatic hydrocarbons. Environmental Science and Technology 24, 1706±1711. Yang, S.Y.N., Connell, D.W., Hawker, D.W., Kayal, S.I., 1991. Polycyclic aromatic hydrocarbons in air, soil and vegetation in the vicinity of an urban roadway. Science of the Total Environment 102, 229±240. Yegorov, D., Trapido, M., Rajur, K., Tultchinsky, V., Zotov, A., 1989. In¯uence of the oil shale power industry of northeastern Estonia on Lake Peipsi. Proceedings of the Estonian Academy of Sciences and Biology 38, 131±136.