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Monitoring of organic pollutants in coastal waters of the Gulf of Gdańsk, Southern Baltic
Marine Pollution Bulletin 49 (2004) 264–276 www.elsevier.com/locate/marpolbul
Monitoring of organic pollutants in coastal waters of the sk, Southern Baltic Gulf of Gdan Agata Kot-Wasik *, Jolanta Dez bska, Jacek Namiesnik Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology, 11/12 Narutowicz Str., PL 80-952 Gdansk-Wrzeszcz, Poland
Abstract This paper presents an overview of changes in organic pollution of coastal waters of the Gulf of Gda nsk (Baltic Sea). Toxic pollutants including volatile organic compounds (VOC), volatile organohalogen compounds (VOX), chlorophenols, phenoxyacids, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were determined in seawater from the Gulf of Gda nsk coastal waters in the period 1996–2001. In the case of the Gulf of Gda nsk, non-conservative behaviour of VOC was observed due to random temporal and spatial of inputs along the Vistula estuary and to the dilution of VOC-enriched river water with seawater. The concentrations of VOX in seawater decreased throughout the period and the concentrations of VOX were in the range of few ng dm3 up to 250 ng dm3 , similar to estuaries elsewhere. The average concentrations of chlorophenols and phenoxyacids were between 0.1 and 6.0 and 0.05 and 2.2 lg dm3 , respectively. However, remarkably high concentrations of 2,4-dichlorophenol (6 lg dm3 ) were obtained in samples collected from the Vistula River. Generally concentrations of PCBs did not exceed few ng dm3 with the exception of 1999, when all samples exhibited elevated concentrations of PCBs. In addition, higher concentrations of PCBs in the open sea compared to river waters suggested localised inputs. Due to the ability of most organic pollutants to bioaccumulate and biomagnify, especially the persistent organic pollutants, continued monitoring is of crucial importance for the health of marine life in the Gulf of Gda nsk. 2004 Elsevier Ltd. All rights reserved. Keywords: Gulf of Gda nsk (Baltic Sea); Organic pollutants; Monitoring; PAHs; PCBs; VOC; VOX
1. Introduction The Baltic Sea is a relatively young sea influenced by the Atlantic Ocean. Moreover, it is shallow and is mainly surrounded by land and is, therefore, more vulnerable to pollution than other marine areas because of restricted water exchange with the North Sea. The residence time of water in the central Baltic is estimated to be over 25 years. Numerous rivers drain into the sea from Central and Northern Europe, including 14 countries. The catchment area is more than 1.7 million km2 and it transports approximately 480 km3 freshwater annually to the east and north of the Baltic Sea (Szefer, 2002). Eighty-five million people live in the Baltic Sea catchment, most of which is characterised by highly developed industry and agriculture. In general, the
*
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Baltic Sea is regarded as a huge natural wastewater treatment plant which is expected to cope with many discharges of different origin and composition (HELCOM, 1996). For example, in the mid-1980s approximately 30,000 t a1 of chlorinated organic compounds were discharged into the Baltic from pulp mills. Since then the amount has decreased significantly due to technical improvements. The Gulf of Gda nsk, consisting of the Vistula Lagoon (an almost land-locked and anthropogenically stressed area), the semi-enclosed Bay of Puck and the mouth of the Vistula (Fig. 1), is a shallow water basin with a sandy bottom. It is separated from the Baltic Proper by the Hel Peninsula, which limits the exchange of water. Within the last 30 years significant changes in conditions of the Gulf of Gda nsk have been: increased eutrophication, increased concentrations of heavy metals in the sediments, oxygen deficiency, the presence of hydrogen sulphide in the benthos and changes in species patterns (Cederwall and Elmgren, 1990; Rydberg et al.,
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Fig. 1. Sampling sites along coastal zone of the Gulf of Gda nsk chosen for seasonal analyses.
1990; Smayda, 1997; HELCOM, 1993, 1996; ŁysiakPastuszak et al., 2000).The Gda nsk region is designated as one of the 27 ecologically endangered areas in Poland and one of 132 pollution ‘hot spots’ in the Baltic (Szefer, 2002). Within the last 20 years studies of the distribution and spatio-temporal variability of organic compounds in estuarine environments have increased. Apart from methane, VOC represent <0.5% of total dissolved organic carbon (DOC) in seawater. VOC may constitute up to 10% of DOC in relatively unpolluted waters (Wakeham et al., 1986), which may be due to anthropogenic and natural (e.g. phytoplankton) inputs. The VOC are mainly alkanes and aromatic hydrocarbons with boiling points between those of n-C6 and n-C18. Within Europe, VOCs have been determined in the Mediterranean Sea (Marchand et al., 1988) and in the estuarine salinity range from 30 to 35 (Dewulf and van Langenhove, 1997; Dewulf et al., 1998; Roose et al., 2001). Polycyclic aromatic hydrocarbons (PAHs) enter the aquatic environment via wet or dry atmospheric fallout, urban runoff, municipal and industrial effluents and oil spillage. The solubility of PAHs in water is low due to their hydrophobic nature (log Kow ¼ 3–8) and it decreases with increasing molecular weight. Recently, the frequency of occurrence and the concentrations of PAHs have been evaluated in aquatic systems (Manoli and Samara, 1999). PAH concentrations at offshore sites are usually low or undetectable, while higher concentrations are observed in many coastal and estuarine waters (Dachs et al., 1997; Witt, 1995). Few data are available for dissolved polychlorinated biphenyls (PCBs), which is due to their low solubility. Because of the multiplicity of parameters controlling PCBs geochemistry, together with analytical problems,
PCBs data are difficult to interpret. Some authors consider that algae may play an important role in the marine geochemistry of PCBs. According to recent data (Konat and Kowalewska, 2001) at present the main source of PCBs for the southern Baltic is not a direct consequence of human activity, but from floods and heavy rains washing these compounds from land to the sea.
2. Experimental 2.1. Sampling sites for seawater The following sampling sites along Polish coastal line, within the area of the coastal waters of the Gulf of Gda nsk, were chosen for the seasonal analyses: Hel (H), Władysławowo (W), Gdynia beach (G), GdyniaOrłowo cliff (O), Gda nsk-Brzezno jetty (B), Vistula mouth (U), Kiezmark (K). The sampling sites (Fig. 1) are situated (a) in the open sea, where most of recreation sites are set and (b) in the sea shore area of the Gulf of Gda nsk, where the industry and big cites with their infrastructure are located. The seawaters samples from a location 50 m from the sea shore were collected episodically and were analysed for the presence of different organic contaminants. The site descriptions are presented in Table 1. 2.2. Determination of seawater parameters pH: Determination of pH was done immediately after delivery of samples to laboratory. Measurement was made with a glass electrode EsAgP309W and microcomputer pH meter CX-315 Elmetron. The temperature
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Table 1 Description of sampling sites Sampling site
Abbreviation
Description
Hel
(H)
Władysławowo Tricity-Gdynia beach
(W) (G)
Tricity-Gdynia Orłowo cliff Tricity-Gda nsk Brzezno molo
(O) (B)
Vistula mouth Kiezmark
(U) (K)
Situated at the top end of the Hel Peninsula; one side adjacent to the open sea, the other is laying within the Gulf of Gda nsk, its port and beaches Situated in Hel Peninsula; fish industry, fish port and bathing places on the open sea Typical recreation area situated in the centre of the town; neighbourhood of shipyard and port, with commercial or tourist passenger vessels Typical recreation area surrounded by trees, beaches and sea Typical recreation area in the neighbourhood of park; further neighbourhood of shipyard; north port, petroleum refinery, phosphates fertilisers; close to the entrance of the biggest port in the Gulf of Gda nsk Vistula mouth, no direct point sources of pollution Situated 40 km upstream from Vistula mouth; river carrying waters from catchment area
of water samples during measurement was always between 18 and 21 C. The electrode was pre-calibrated with buffers (pH ¼ 7.00, 2.1; Merck reagent CertiPUR 1.99002). To confirm electrode stability, after set of measurements of seawater samples, the glass electrode was placed again in buffer solution (pH ¼ 7.00). Determination of toxicity of water: Toxicity measurements of water samples were performed using the ToxAlert 100 test, which is based on measurement of decreasing luminescence of Vibrio fischeri bacterium added to a water sample. Salinity of seawater: Salinity of seawater samples was not determined but values were obtained from a monitoring cruise by the Institute of Meteorology and Water Management, Maritime Branch in Gdynia, Poland (http://baltyk.imgw.gdynia.pl/cruises/reports/). 2.3. Analytical procedures for the determination of organic pollutants in seawater Determination of volatile organic compounds (VOC): VOC, such as benzene, toluene, ethylobenzene, xylenes, decane, dodecane, nonanal, decanal were analysed using methods described previously (Namiesnik et al., 1990; Wasik et al., 1998; Wardencki et al., 2000). Briefly, 10 ml of water samples collected in glass bottles were taken for analysis and 2 ll of 4-bromo-fluorobenzene was added as an internal standard. Analytes were isolated based on a purge and trap technique (PT), in which samples were purged with a stream of argon for 10 min. Analytes were
trapped in a micro-trap, from where they were desorbed at 250 C for 60 s and analysed using a gas chromatography–mass spectrometry (GC–MS) technique. Detailed conditions for the PT–GC–MS system used for the determination of VOC in seawater sample are presented in Table 2. The detection limit for each VOC was 0.1 ng dm3 . Determination of volatile organohalogen compounds (VOX): VOX compounds (CHCl3 , CHBrCl2 , C2 HCl3 , CHBr2 Cl, CHBr3 , C2 Cl4 , CCl4 ) were analysed based on direct aqueous injection and GC-ECD identification and quantification (Biziuk, 2001; Janicki et al., 2002; Polkowska et al., 2000a). The conditions for the analysis performed with the GC-ECD are shown in Table 3. The detection limit for this method was 10 ng dm3 for all species being determined with two exceptions: 50 ng dm3 for CHBr3 and 1 ng dm3 for CH3 Cl. Determination of phenols and phenoxyacids: Phenols, such as phenol, 2-chlorophenol, 2,4-dichlorophenol, 4-chloro-3-methylphenol, pentachlorophenol and phenoxyacids, such as 2,4-D, MCPA, dichlorprop, mecoprop, dinoseb were analysed according to the method described by Kot-Wasik et al. (2004). Briefly, water samples were collected in amber glass bottles and were acidified with orthophosphoric acid to pH < 2. The analytes were pre-concentrated using a solid phase extraction (SPE) method with EN 200 mg (Merck) columns. Before usage, each column was conditioned with acetonitrile (2 · 2.5 ml), methanol (2 · 2.5 ml), HPLC grade water (2 · 2.5 ml) and water acidified to pH ¼ 2 by
Table 2 Working parameters of PT–GC–MS system used for the determination of VOC Gas chromatograph
Trace GC, Termo Quest
Column
RTX-624 Restek Corporation, 60 m · 0.32 mm ID fused silica, Df ¼ 1.8 lm, 6% cyjanoprophylophenyl, 94% dimethylepolisiloksan Thermal desorber connected with microtrap; purging gas: argon: 20 m3 min1 ; desorption time: 10 min Sorbent: 80 g Tenax TA/30 mg Carbosieve III Helium: 100 kPa, 2 cm3 min1 35 C through 2 min, 5 C min1 up to 100 C, 10 C min1 up to 240 C through 20 min Mass spectrometer (scan: 10–450)
Injector Microtrap Carrier gas Temperature program Detector
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Table 3 Working parameters of GC-ECD system used for the determination of VOX Chromatograph type Column (length · internal diameter · thickness of stationary phase film) Injection system Carrier gas Temperature program Injection temperature Injected sample volume Detector
orthophosphoric acid (2 · 2.5 ml). Then 300 ml of the seawater sample was passed through the column. Afterwards, columns were washed with HPLC grade water and dried in a stream of nitrogen. Elution into glass vials was realised with acetonitrile (2 · 2.5 ml). Then 1 ml of acidified water was added and solvent was evaporated to 1 ml. Immediately before chromatographic analysis each extract was diluted with water acidified with phosphoric acid (1:1) and a sample volume of 100 ll was injected. The conditions of the chromatographic system used for the final determination, with HPLC-DAD, are presented in Table 4. The detection limits were different for each analyte and, together with recoveries, are included in the table. Determination of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs): PAHs and PCBs were analysed using a method published earlier (Wolska, 2002; Galer et al., 2000; Zygmunt and Namiesnik, 2002). Briefly, seawater samples were collected in amber glass bottles. An isolation and enrichment step was performed with SPE extraction on C18 cartridges by passing 0.5 dm3 of the water sample with internal standards added: deuterated naphthalene, deu-
GC 6180 VEGA Carlo Erba-Fisons 30 m · 0.32, DB: 1 · 5 lm, precolumn 2 m · 0.32 mm Direct injection on column (cold on-column) Hydrogen Isotherm 104 C Below 100 C 2 ll ECD, 350 C
terated benzo(a)anthracene and PCB 209. Cartridges were conditioned prior to use with dichloromethane (3 ml) and later with methanol (2 · 3 ml) and HPLC grade water (3 ml). The trapped compounds were extracted from dried cartridges with dichloromethane (8 ml). Extracts were evaporated to a volume of 0.3 ml with stream of nitrogen and analysed. Final determination was performed using GC–MS technique. All working parameters are shown in Table 5. The detection limits was 2 ng dm3 for each aromatic compound and 3 ng dm3 for each PCB’s congener.
3. Results and discussion 3.1. Temperature, pH, toxicity and salinity The pH of seawater from the coastal zone varied from 8 to 8.5 with the more alkaline values associated with samples from the Vistula River, probably because of the discharge of untreated wastewaters. The toxicity varied from 10 units for seawater samples collected from Hel and Władysławowo up to 65 for water sampled in
Table 4 Working parameters of HPLC-DAD system used for the final determination of chlorophenols and phenoxyacids Parameters
Details
Chromatograph Mobile phase
Merck Hitachi 7000 series A: H2 O + 0.1% v/v CH3 COOH B: ACN:MeOH (1:1, v/v) + 0.01% v/v CH3 COOH At time 0–75% A, then gradient in 15 min 43% A, then in 22 min 35% A and at 30 min 0% A kept for 10 min 0.7 ml min1 25 C 100 ll
Gradient Flow rate Temperature Injection volume Detection parameters Compound Phenol 2-Chlorophenol 2,4-Dichlorophenol 4-Chloro-3-methylphenol Pentachlorophenol 2,4-D MCPA Dichlorprop Mecoprop Dinoseb
Wavelengths of detection
Limit of detection (lg dm3 )
270 280 280 280 305 230 230 230 230 305
0.15 0.05 0.05 0.05 0.20 0.06 0.06 0.09 0.09 0.03
nm nm nm nm nm nm nm nm nm nm
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Table 5 Working parameters of GC–MS system used for the determination of PAHs and PCBs Chromatograph
TRACE GC Termo Quest
Injection system Injected sample volume Carrier gas Connector temperature Column Integration system Temperature program Detector
Cold on-column 2 ll Helium: 70 kPa 250 C Rtx: 5MS, 30 m, 0.25 mm, 0.25 lm Mass Lab 40–120 C (40 C min1 ); then from 280 C (5 C min1 ); 280 C through 12 min Mass spectrometer (SIM)
the Vistula River. Seawater samples from Gdynia and Gda nsk exhibit toxicity in between 25 and 32. The only exception was observed for Gdynia-Orłowo, where toxicity was relatively low (always between 1–5 units). Within sampling period the salinity of surface waters of Gdansk Bay varied from 7.3 to 8.4 but was lower in the vicinity of Vistula River 5.5–6.5. The salinity of the surface waters is strongly influenced by the inflow of the Vistula River with a hydrological (salinity) front being formed approximately 10 km seaward from mouth of Vistula River.
tion of VOX in the estuaries of the Scheldt, Thames, Loire and Rhine (Christof et al., 2002) is in the same range of few ng dm3 up to 250 ng dm3 . The highest concentrations were obtained for trichloromethane, which is one of the main by-products of water chlorination and intense shipping observed during sampling. However, certain marine algae also produce VOX. As the number of VOX halogen atoms increases adsorption to particles increases and for this reason it is important to analyse unfiltered water to obtain the total concentration of VOX.
3.2. Volatile organic compounds (VOC)
3.4. Phenoxyacids and chlorophenols
The observed VOC concentrations in the estuaries are highly variable but can nevertheless be classified into a general distribution pattern type, for which the mixing of river water with seawater is the main factor determining the concentration of VOC along the salinity gradient. Detailed data showing annual average fluctuations in VOC concentrations in the Gulf of Gda nsk and Vistula River are shown in Fig. 2. Fig. 2 indicates a dilution of VOC-enriched river water with seawater, which is opposite to that observed for the Daire and Thames, where increases along salinity gradient were observed, suggesting a marine source (Christof et al., 2002). For the Gulf of Gda nsk, a nonconservative behaviour of VOC was seen due to random temporal and spatial of inputs from various sources, such as power plants, harbour, ships, urban runoff and natural sources. Trends towards furthers studies of VOC as pollutants and as natural substances may be warranted since over the last decade there has been concern expressed by regulatory authorities and research institutions about the ecotoxicological effects of anthropogenic VOC within marine ecosystems.
Within the monitoring period no chlorophenols were detected in seawater samples obtained up to 2001. In autumn and spring of the last two years, chlorophenols and phenoxyacids were observed in waters at low lg dm3 concentrations. The average concentrations of the chlorophenols and phenoxyacids ranged between 0.1 and 6.0 and 0.05 and 2.2 lg dm3 , respectively. Typical seasonal changes in concentration of phenoxyacids and chlorophenols have been observed, as shown in Fig. 4. High concentrations of 2,4-dichlorophenol (6 lg dm3 ) were observed in samples collected from the Vistula River, which carry pollutants from the catchment area. This result compares to a relatively high content of chlorophenols and phenoxyacids found in samples collected from the pier in Gdansk, where recreation areas and beaches are located. Other authors (Veningerova et al., 1998; Rawn et al., 1999) detected very similar levels of chlorinated phenols and phenoxyacid herbicides. Phenoxyacids could possibly originate due to the leaching processes from surrounding agricultural area while chlorophenols might be present because they come from the degradation processes of phenoxyacid herbicides as well as industrial activity. Seasonal variations in their concentration confirm, that degradation is significant source of chlorophenols presence in seawater samples (Kot-Wasik et al., 2004). In general five times higher concentrations of phenoxyacids were detected in the spring period when these herbicides are applied in agriculture. Significantly higher concentrations of chlorophenols are also evident in spring compared with
3.3. Volatile organohalogen compounds (VOX) The results obtained for VOX are summarised and shown in Fig. 3, where a continuous decrease in VOX content in seawaters of the Gulf of Gda nsk is clearly demonstrated. Comparison of our results with data published elsewhere demonstrates that the concentra-
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Fig. 2. Annual average concentrations of VOC (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Gdynia, (d) Vistula.
autumn, which suggests that degradation processes are the sources of phenol derivates rather that human activity. According to Juhler et al. (2001) and Pozo et al. (2001) the main potential metabolites of phenoxyacids are chlorophenols. 3.5. Polycyclic aromatic hydrocarbons (PAHs) Concentrations for PAHs in waters collected along the coastal zone of the Gulf of Gda nsk are illustrated in Fig. 5. The aromatic hydrocarbons were divided into three groups: low molecular weight 128–178 g/mol (2–3 rings) (Fig. 5(1)) medium molecular weight 202–228 g/
mol (4 rings) (Fig. 5(2)) and high molecular weight 252– 278 g/mol (5–6 rings) (Fig. 5(3)). Generally, PAHs were determined the ng dm3 level and the determined compounds were naphthalene, phenanthrene, benzo(b)fluoranthene, anthracene. In case of low molecular weight PAHs their concentration varied from a few ng dm3 recorded in 1996 up to hundreds ng dm3 observed in 1998. Levels of moderate PAHs were also lower in 1996 with increasing tendency up to 1999 year. High molecular weight aromatic hydrocarbons were present at significantly lower concentrations with the exception of 1999, when values were always higher than either before or after. In case of
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Fig. 3. Annual average concentrations of VOX (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Gdynia, (d) Vistula.
the coastal waters of the Gulf of Gda nsk, the probable source is the neighbouring location of petroleum refinery and, possibly, car and ship transportation, which increases year by year, especially during summer period. Similar PAH concentrations were obtained by other authors, although it should be stressed that a direct comparison with literature data is difficult due to differences in the phase and the compounds considered in each study. The dissolved PAHs content in waters from
off-shore of Barcelona were 1800 pg dm3 . PAHs in the dissolved phase were found up to 30 and 50 ng dm3 in summer and winter, respectively, which is comparable with data obtained for the coastal waters of the Gulf of Gda nsk. 3.6. Polychlorinated biphenyls (PCBs) Content of PCBs in seawater samples in the area of the coastal zone of the Gulf of Gda nsk has been
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Fig. 4. Seasonal changes in the concentration (lg dm3 ) of chlorophenols (a and b) and phenoxyacids (c and d). Data for seawater samples collected in spring period are followed by data collected for autumn period.
estimated at low ppt level with some extraordinary exceptions. Detailed data are illustrated in Fig. 6. Within the previous 8 years of measurement of PCBs did not exceed few ng dm3 , with the exception of 1999, when all samples had extraordinarily high concentrations of PCBs. Higher concentrations of PCBs in open sea (Władysławowo) and in Gdynia and in Kiezmark suggest local pollution sources. Also, samples collected in Gdynia in 1997 and 1998 had PCBs at relatively
high concentrations in comparison with other times. In water, PCBs can exist either in the truly dissolved phase or adsorbed to suspended particles. Although the water solubility of PCBs is low, the total amount of PCBs in water can be elevated due to the presence of suspended particles with adsorbed PCBs. Since it is well known, that PCBs are poorly soluble in water and they have the tendency to accumulate in sediments and fatty tissues of fish, shellfish and seals. Even low
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Fig. 5. Annual average concentrations of PAHs (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Gdynia, (d) Vistula.
concentrations PCBs may cause in future damage in animals and, therefore, should be monitored continuously. According to data published by Renk (1993) relatively high concentrations of PCBs are observed in sediments collected from the Gda nsk Deep and in the Gulf of Gda nsk. Total content of PCBs in these sediments varies from hundred ng g1 up to hundreds of lg g1 , which clearly demonstrates sorption ability
of these compounds. Because of the fact that algae seems to have an significant role in the transport and distribution of PCBs, a high correlation of PCBs with chlorophyll a derivatives (products of zooplankton grazing) observed by other authors (Green and Knutzen, 2003) indicates that PCBs are ingested by zooplankton with phytoplankton and then exuded with fecal pellets. Eutrophication is a basic problem of the Baltic, hence probable that living and decomposed algae
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Fig. 5 (continued)
might have a decisive influence upon the geochemistry of PCBs. In the Baltic PCBs were determined first in animal tissues (fish, molluscs, birds) (HELCOM, 1996) and some of these values were alarmingly high (Falandysz et al., 1999). There are only few data available for PCB concentrations in water (HELCOM, 1996; Schlultz-Bull et al., 1995) and sediments of the Baltic Sea also have not been intensively studied (Parttila and Haahti, 1986; Van Bavel et al., 1996). Data for sediments of the Polish southern Baltic zone are scarce and indicate very low PCB concentrations.
4. Conclusions The results obtained during monitoring of the state of the Gulf of Gda nsk not show very high pollution levels in coastal waters by volatile and semi-volatile organic pollutants, such as VOC, VOX, chlorophenols, phenoxacids, PCBs and PAHs. The present state of the Gulf of Gda nsk––in case of the organic pollutants, specially those belonging to the persistent organic pollutant class––is certainly affected mostly by the human activity. Amounts of pollutants discharged via either rivers or atmosphere should be controlled and limited in the
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Fig. 5 (continued)
future in order to keep our seashore line in good condition. In view of the fact that degradation processes of the environment (also in the area of the Gulf of Gda nsk) are continuous and long-term development there is a necessity of a permanent control and improvement of the conditions of the environment. This is of vital importance for the future survival of the Baltic. The methods, which have been proposed and applied, were successfully used for the determination of organic compound in seawater samples and can be applied by any other analysts.
Acknowledgements The authors are grateful to Michael Maybeck (University in Paris, France) for valuable discussion in the preparation of this paper. M. Biziuk and B. Zukowska are kindly thanked for co-ordination of sampling and collection of data. A. Wasik prepared the map. The authors gratefully acknowledge all members of the Department of Analytical Chemistry (Gda nsk University of Technology) and Ph.D. Students are for GC and HPLC analyses of samples. This study was realised and
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Fig. 6. Annual average concentrations of PCBs (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Orłowo, (d) Kiezmark.
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petroleum hydrocarbons in rain water and snow by means of gas chromatography. Chemical Analysis 45, 537–550. Pozo, O., Pitarch, E., Sancho, J.V., Hernandez, F., 2001. Determination of the herbicide 4-chloro-2-methylphenoxyacetic acid and its main metabolite, 4-chloro-2-methylphenol in water and soil by liquid chromatography–electrospray tandem mass spectrometry. Journal of Chromatography A 923, 75–85. Rawn, D.F.K., Halldorson, T.H.J., Woychuk, R.N., Muir, D.C.G., 1999. Water Quality Research Journal of Canada 34 (2), 183–219. Renk, H., 1993. Primary production of Puck Bay, in: Korzeniewski, K. (Ed.), Puck Bay’s Foundation of Development of University Gdansk Gda nsk, pp. 338–365 (in Polish). Roose, P., Dewulf, J., Brinkman, U.A.Th., van Langenhove, H., 2001. Measurement of volatile organic compounds in sediments of the Scheldt Estuary and the southern North Sea. Water Research 35, 1478–1488. Rydberg, L., Edler, L., Floderus, S., Granelli, W., Elmgren, R., 1990. Interaction between supply of nutrients, primary production, sedimentation and oxygen consumption in SE Kattegat. Ambio 3, 134–141. Schlultz-Bull, D.E., Petrick, G., Kanna, N., Duinker, J.C., 1995. Distribution of individual chlorobiphenyls (PCB) in solution and suspension in the Baltic Sea. Marine Chemistry 48, 245–270. Smayda, T.J., 1997. What is a bloom? A commentary. Limnology & Oceanography 4, 1132–1136. Szefer, P., 2002. Metals, metalloids and radionuclides in the Baltic Sea ecosystem. In: Trace metals in the Environment. Elsevier, London. Van Bavel, B., Andersson, P., Wingfors, H., Ahgren, J., Bergqvist, P.A., Norrgren, L., Rappe, C., Tysklind, M., 1996. Multivariate modelling of PCB bioaccumulation in three-spined stickleback (Gasterosteus aculeatus). Environmental Toxicology and Chemistry 15, 947–954. Veningerova, M., Prachar, V., Kovacicova, J., Uhnak, J., 1998. Fresen. Environ. Bull. 7, 224–231. Wakeham, S.G., Canuel, E.A., Doering, P.H., 1986. Geochemistry of volatile organic compounds in seawater: mesocosm experiments with 14-carbon model compounds. Geochimica Cosmochimica Acta 50, 1163–1172. Wardencki, W., Staniszewska, M., Wolska, L., Janicki, W., Namiesnik, J., 2000. Evaluation of pollution degree of the Odra river basin with organic compounds after 97 summer flood. Part II. Determination of volatile and semivolatile compounds in post flood sediments of the Odra basin. Chemical Analysis 45, 291–296. Wasik, A., Rodriguez-Pereiro, I., Łobi nski, R., 1998. Interface for time-resolved introduction of gaseous analytes for atomic spectrometry by purge-and-trap multicapillary gas chromatography (PTMGC). Spectrochimica Acta Part B 53, 867–879. Witt, G., 1995. Polycyclic aromatic hydrocarbons in water and sediments of the Baltic Sea. Marine Pollution Bulletin 31, 237–248. Wolska, L., 2002. Miniaturised analytical procedure of determining polycyclic aromatic hydrocarbons and polychlorinated biphenyls in bottom sediments. Journal of Chromatography A 959, 173–180. Zygmunt, B., Namiesnik, J., 2002. Sampling selected solid materials. In: Pawliszyn, J. (Ed.), Sampling and Sample Preparation for Field and Laboratory. Fundamentals and New Directions in Sample Preparation. In: Barcel o, D. (Ed.), Comprehensive Analytical Chemistry, vol. 37. Elsevier, Amsterdam, pp. 61–86 (Chapter 3).
Monitoring of organic pollutants in coastal waters of the sk, Southern Baltic Gulf of Gdan Agata Kot-Wasik *, Jolanta Dez bska, Jacek Namiesnik Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology, 11/12 Narutowicz Str., PL 80-952 Gdansk-Wrzeszcz, Poland
Abstract This paper presents an overview of changes in organic pollution of coastal waters of the Gulf of Gda nsk (Baltic Sea). Toxic pollutants including volatile organic compounds (VOC), volatile organohalogen compounds (VOX), chlorophenols, phenoxyacids, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were determined in seawater from the Gulf of Gda nsk coastal waters in the period 1996–2001. In the case of the Gulf of Gda nsk, non-conservative behaviour of VOC was observed due to random temporal and spatial of inputs along the Vistula estuary and to the dilution of VOC-enriched river water with seawater. The concentrations of VOX in seawater decreased throughout the period and the concentrations of VOX were in the range of few ng dm3 up to 250 ng dm3 , similar to estuaries elsewhere. The average concentrations of chlorophenols and phenoxyacids were between 0.1 and 6.0 and 0.05 and 2.2 lg dm3 , respectively. However, remarkably high concentrations of 2,4-dichlorophenol (6 lg dm3 ) were obtained in samples collected from the Vistula River. Generally concentrations of PCBs did not exceed few ng dm3 with the exception of 1999, when all samples exhibited elevated concentrations of PCBs. In addition, higher concentrations of PCBs in the open sea compared to river waters suggested localised inputs. Due to the ability of most organic pollutants to bioaccumulate and biomagnify, especially the persistent organic pollutants, continued monitoring is of crucial importance for the health of marine life in the Gulf of Gda nsk. 2004 Elsevier Ltd. All rights reserved. Keywords: Gulf of Gda nsk (Baltic Sea); Organic pollutants; Monitoring; PAHs; PCBs; VOC; VOX
1. Introduction The Baltic Sea is a relatively young sea influenced by the Atlantic Ocean. Moreover, it is shallow and is mainly surrounded by land and is, therefore, more vulnerable to pollution than other marine areas because of restricted water exchange with the North Sea. The residence time of water in the central Baltic is estimated to be over 25 years. Numerous rivers drain into the sea from Central and Northern Europe, including 14 countries. The catchment area is more than 1.7 million km2 and it transports approximately 480 km3 freshwater annually to the east and north of the Baltic Sea (Szefer, 2002). Eighty-five million people live in the Baltic Sea catchment, most of which is characterised by highly developed industry and agriculture. In general, the
*
Corresponding author. Tel./fax: +48-58-3472694. E-mail address: [email protected] (A. Kot-Wasik).
0025-326X/$ - see front matter 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2004.02.014
Baltic Sea is regarded as a huge natural wastewater treatment plant which is expected to cope with many discharges of different origin and composition (HELCOM, 1996). For example, in the mid-1980s approximately 30,000 t a1 of chlorinated organic compounds were discharged into the Baltic from pulp mills. Since then the amount has decreased significantly due to technical improvements. The Gulf of Gda nsk, consisting of the Vistula Lagoon (an almost land-locked and anthropogenically stressed area), the semi-enclosed Bay of Puck and the mouth of the Vistula (Fig. 1), is a shallow water basin with a sandy bottom. It is separated from the Baltic Proper by the Hel Peninsula, which limits the exchange of water. Within the last 30 years significant changes in conditions of the Gulf of Gda nsk have been: increased eutrophication, increased concentrations of heavy metals in the sediments, oxygen deficiency, the presence of hydrogen sulphide in the benthos and changes in species patterns (Cederwall and Elmgren, 1990; Rydberg et al.,
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Fig. 1. Sampling sites along coastal zone of the Gulf of Gda nsk chosen for seasonal analyses.
1990; Smayda, 1997; HELCOM, 1993, 1996; ŁysiakPastuszak et al., 2000).The Gda nsk region is designated as one of the 27 ecologically endangered areas in Poland and one of 132 pollution ‘hot spots’ in the Baltic (Szefer, 2002). Within the last 20 years studies of the distribution and spatio-temporal variability of organic compounds in estuarine environments have increased. Apart from methane, VOC represent <0.5% of total dissolved organic carbon (DOC) in seawater. VOC may constitute up to 10% of DOC in relatively unpolluted waters (Wakeham et al., 1986), which may be due to anthropogenic and natural (e.g. phytoplankton) inputs. The VOC are mainly alkanes and aromatic hydrocarbons with boiling points between those of n-C6 and n-C18. Within Europe, VOCs have been determined in the Mediterranean Sea (Marchand et al., 1988) and in the estuarine salinity range from 30 to 35 (Dewulf and van Langenhove, 1997; Dewulf et al., 1998; Roose et al., 2001). Polycyclic aromatic hydrocarbons (PAHs) enter the aquatic environment via wet or dry atmospheric fallout, urban runoff, municipal and industrial effluents and oil spillage. The solubility of PAHs in water is low due to their hydrophobic nature (log Kow ¼ 3–8) and it decreases with increasing molecular weight. Recently, the frequency of occurrence and the concentrations of PAHs have been evaluated in aquatic systems (Manoli and Samara, 1999). PAH concentrations at offshore sites are usually low or undetectable, while higher concentrations are observed in many coastal and estuarine waters (Dachs et al., 1997; Witt, 1995). Few data are available for dissolved polychlorinated biphenyls (PCBs), which is due to their low solubility. Because of the multiplicity of parameters controlling PCBs geochemistry, together with analytical problems,
PCBs data are difficult to interpret. Some authors consider that algae may play an important role in the marine geochemistry of PCBs. According to recent data (Konat and Kowalewska, 2001) at present the main source of PCBs for the southern Baltic is not a direct consequence of human activity, but from floods and heavy rains washing these compounds from land to the sea.
2. Experimental 2.1. Sampling sites for seawater The following sampling sites along Polish coastal line, within the area of the coastal waters of the Gulf of Gda nsk, were chosen for the seasonal analyses: Hel (H), Władysławowo (W), Gdynia beach (G), GdyniaOrłowo cliff (O), Gda nsk-Brzezno jetty (B), Vistula mouth (U), Kiezmark (K). The sampling sites (Fig. 1) are situated (a) in the open sea, where most of recreation sites are set and (b) in the sea shore area of the Gulf of Gda nsk, where the industry and big cites with their infrastructure are located. The seawaters samples from a location 50 m from the sea shore were collected episodically and were analysed for the presence of different organic contaminants. The site descriptions are presented in Table 1. 2.2. Determination of seawater parameters pH: Determination of pH was done immediately after delivery of samples to laboratory. Measurement was made with a glass electrode EsAgP309W and microcomputer pH meter CX-315 Elmetron. The temperature
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Table 1 Description of sampling sites Sampling site
Abbreviation
Description
Hel
(H)
Władysławowo Tricity-Gdynia beach
(W) (G)
Tricity-Gdynia Orłowo cliff Tricity-Gda nsk Brzezno molo
(O) (B)
Vistula mouth Kiezmark
(U) (K)
Situated at the top end of the Hel Peninsula; one side adjacent to the open sea, the other is laying within the Gulf of Gda nsk, its port and beaches Situated in Hel Peninsula; fish industry, fish port and bathing places on the open sea Typical recreation area situated in the centre of the town; neighbourhood of shipyard and port, with commercial or tourist passenger vessels Typical recreation area surrounded by trees, beaches and sea Typical recreation area in the neighbourhood of park; further neighbourhood of shipyard; north port, petroleum refinery, phosphates fertilisers; close to the entrance of the biggest port in the Gulf of Gda nsk Vistula mouth, no direct point sources of pollution Situated 40 km upstream from Vistula mouth; river carrying waters from catchment area
of water samples during measurement was always between 18 and 21 C. The electrode was pre-calibrated with buffers (pH ¼ 7.00, 2.1; Merck reagent CertiPUR 1.99002). To confirm electrode stability, after set of measurements of seawater samples, the glass electrode was placed again in buffer solution (pH ¼ 7.00). Determination of toxicity of water: Toxicity measurements of water samples were performed using the ToxAlert 100 test, which is based on measurement of decreasing luminescence of Vibrio fischeri bacterium added to a water sample. Salinity of seawater: Salinity of seawater samples was not determined but values were obtained from a monitoring cruise by the Institute of Meteorology and Water Management, Maritime Branch in Gdynia, Poland (http://baltyk.imgw.gdynia.pl/cruises/reports/). 2.3. Analytical procedures for the determination of organic pollutants in seawater Determination of volatile organic compounds (VOC): VOC, such as benzene, toluene, ethylobenzene, xylenes, decane, dodecane, nonanal, decanal were analysed using methods described previously (Namiesnik et al., 1990; Wasik et al., 1998; Wardencki et al., 2000). Briefly, 10 ml of water samples collected in glass bottles were taken for analysis and 2 ll of 4-bromo-fluorobenzene was added as an internal standard. Analytes were isolated based on a purge and trap technique (PT), in which samples were purged with a stream of argon for 10 min. Analytes were
trapped in a micro-trap, from where they were desorbed at 250 C for 60 s and analysed using a gas chromatography–mass spectrometry (GC–MS) technique. Detailed conditions for the PT–GC–MS system used for the determination of VOC in seawater sample are presented in Table 2. The detection limit for each VOC was 0.1 ng dm3 . Determination of volatile organohalogen compounds (VOX): VOX compounds (CHCl3 , CHBrCl2 , C2 HCl3 , CHBr2 Cl, CHBr3 , C2 Cl4 , CCl4 ) were analysed based on direct aqueous injection and GC-ECD identification and quantification (Biziuk, 2001; Janicki et al., 2002; Polkowska et al., 2000a). The conditions for the analysis performed with the GC-ECD are shown in Table 3. The detection limit for this method was 10 ng dm3 for all species being determined with two exceptions: 50 ng dm3 for CHBr3 and 1 ng dm3 for CH3 Cl. Determination of phenols and phenoxyacids: Phenols, such as phenol, 2-chlorophenol, 2,4-dichlorophenol, 4-chloro-3-methylphenol, pentachlorophenol and phenoxyacids, such as 2,4-D, MCPA, dichlorprop, mecoprop, dinoseb were analysed according to the method described by Kot-Wasik et al. (2004). Briefly, water samples were collected in amber glass bottles and were acidified with orthophosphoric acid to pH < 2. The analytes were pre-concentrated using a solid phase extraction (SPE) method with EN 200 mg (Merck) columns. Before usage, each column was conditioned with acetonitrile (2 · 2.5 ml), methanol (2 · 2.5 ml), HPLC grade water (2 · 2.5 ml) and water acidified to pH ¼ 2 by
Table 2 Working parameters of PT–GC–MS system used for the determination of VOC Gas chromatograph
Trace GC, Termo Quest
Column
RTX-624 Restek Corporation, 60 m · 0.32 mm ID fused silica, Df ¼ 1.8 lm, 6% cyjanoprophylophenyl, 94% dimethylepolisiloksan Thermal desorber connected with microtrap; purging gas: argon: 20 m3 min1 ; desorption time: 10 min Sorbent: 80 g Tenax TA/30 mg Carbosieve III Helium: 100 kPa, 2 cm3 min1 35 C through 2 min, 5 C min1 up to 100 C, 10 C min1 up to 240 C through 20 min Mass spectrometer (scan: 10–450)
Injector Microtrap Carrier gas Temperature program Detector
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Table 3 Working parameters of GC-ECD system used for the determination of VOX Chromatograph type Column (length · internal diameter · thickness of stationary phase film) Injection system Carrier gas Temperature program Injection temperature Injected sample volume Detector
orthophosphoric acid (2 · 2.5 ml). Then 300 ml of the seawater sample was passed through the column. Afterwards, columns were washed with HPLC grade water and dried in a stream of nitrogen. Elution into glass vials was realised with acetonitrile (2 · 2.5 ml). Then 1 ml of acidified water was added and solvent was evaporated to 1 ml. Immediately before chromatographic analysis each extract was diluted with water acidified with phosphoric acid (1:1) and a sample volume of 100 ll was injected. The conditions of the chromatographic system used for the final determination, with HPLC-DAD, are presented in Table 4. The detection limits were different for each analyte and, together with recoveries, are included in the table. Determination of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs): PAHs and PCBs were analysed using a method published earlier (Wolska, 2002; Galer et al., 2000; Zygmunt and Namiesnik, 2002). Briefly, seawater samples were collected in amber glass bottles. An isolation and enrichment step was performed with SPE extraction on C18 cartridges by passing 0.5 dm3 of the water sample with internal standards added: deuterated naphthalene, deu-
GC 6180 VEGA Carlo Erba-Fisons 30 m · 0.32, DB: 1 · 5 lm, precolumn 2 m · 0.32 mm Direct injection on column (cold on-column) Hydrogen Isotherm 104 C Below 100 C 2 ll ECD, 350 C
terated benzo(a)anthracene and PCB 209. Cartridges were conditioned prior to use with dichloromethane (3 ml) and later with methanol (2 · 3 ml) and HPLC grade water (3 ml). The trapped compounds were extracted from dried cartridges with dichloromethane (8 ml). Extracts were evaporated to a volume of 0.3 ml with stream of nitrogen and analysed. Final determination was performed using GC–MS technique. All working parameters are shown in Table 5. The detection limits was 2 ng dm3 for each aromatic compound and 3 ng dm3 for each PCB’s congener.
3. Results and discussion 3.1. Temperature, pH, toxicity and salinity The pH of seawater from the coastal zone varied from 8 to 8.5 with the more alkaline values associated with samples from the Vistula River, probably because of the discharge of untreated wastewaters. The toxicity varied from 10 units for seawater samples collected from Hel and Władysławowo up to 65 for water sampled in
Table 4 Working parameters of HPLC-DAD system used for the final determination of chlorophenols and phenoxyacids Parameters
Details
Chromatograph Mobile phase
Merck Hitachi 7000 series A: H2 O + 0.1% v/v CH3 COOH B: ACN:MeOH (1:1, v/v) + 0.01% v/v CH3 COOH At time 0–75% A, then gradient in 15 min 43% A, then in 22 min 35% A and at 30 min 0% A kept for 10 min 0.7 ml min1 25 C 100 ll
Gradient Flow rate Temperature Injection volume Detection parameters Compound Phenol 2-Chlorophenol 2,4-Dichlorophenol 4-Chloro-3-methylphenol Pentachlorophenol 2,4-D MCPA Dichlorprop Mecoprop Dinoseb
Wavelengths of detection
Limit of detection (lg dm3 )
270 280 280 280 305 230 230 230 230 305
0.15 0.05 0.05 0.05 0.20 0.06 0.06 0.09 0.09 0.03
nm nm nm nm nm nm nm nm nm nm
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Table 5 Working parameters of GC–MS system used for the determination of PAHs and PCBs Chromatograph
TRACE GC Termo Quest
Injection system Injected sample volume Carrier gas Connector temperature Column Integration system Temperature program Detector
Cold on-column 2 ll Helium: 70 kPa 250 C Rtx: 5MS, 30 m, 0.25 mm, 0.25 lm Mass Lab 40–120 C (40 C min1 ); then from 280 C (5 C min1 ); 280 C through 12 min Mass spectrometer (SIM)
the Vistula River. Seawater samples from Gdynia and Gda nsk exhibit toxicity in between 25 and 32. The only exception was observed for Gdynia-Orłowo, where toxicity was relatively low (always between 1–5 units). Within sampling period the salinity of surface waters of Gdansk Bay varied from 7.3 to 8.4 but was lower in the vicinity of Vistula River 5.5–6.5. The salinity of the surface waters is strongly influenced by the inflow of the Vistula River with a hydrological (salinity) front being formed approximately 10 km seaward from mouth of Vistula River.
tion of VOX in the estuaries of the Scheldt, Thames, Loire and Rhine (Christof et al., 2002) is in the same range of few ng dm3 up to 250 ng dm3 . The highest concentrations were obtained for trichloromethane, which is one of the main by-products of water chlorination and intense shipping observed during sampling. However, certain marine algae also produce VOX. As the number of VOX halogen atoms increases adsorption to particles increases and for this reason it is important to analyse unfiltered water to obtain the total concentration of VOX.
3.2. Volatile organic compounds (VOC)
3.4. Phenoxyacids and chlorophenols
The observed VOC concentrations in the estuaries are highly variable but can nevertheless be classified into a general distribution pattern type, for which the mixing of river water with seawater is the main factor determining the concentration of VOC along the salinity gradient. Detailed data showing annual average fluctuations in VOC concentrations in the Gulf of Gda nsk and Vistula River are shown in Fig. 2. Fig. 2 indicates a dilution of VOC-enriched river water with seawater, which is opposite to that observed for the Daire and Thames, where increases along salinity gradient were observed, suggesting a marine source (Christof et al., 2002). For the Gulf of Gda nsk, a nonconservative behaviour of VOC was seen due to random temporal and spatial of inputs from various sources, such as power plants, harbour, ships, urban runoff and natural sources. Trends towards furthers studies of VOC as pollutants and as natural substances may be warranted since over the last decade there has been concern expressed by regulatory authorities and research institutions about the ecotoxicological effects of anthropogenic VOC within marine ecosystems.
Within the monitoring period no chlorophenols were detected in seawater samples obtained up to 2001. In autumn and spring of the last two years, chlorophenols and phenoxyacids were observed in waters at low lg dm3 concentrations. The average concentrations of the chlorophenols and phenoxyacids ranged between 0.1 and 6.0 and 0.05 and 2.2 lg dm3 , respectively. Typical seasonal changes in concentration of phenoxyacids and chlorophenols have been observed, as shown in Fig. 4. High concentrations of 2,4-dichlorophenol (6 lg dm3 ) were observed in samples collected from the Vistula River, which carry pollutants from the catchment area. This result compares to a relatively high content of chlorophenols and phenoxyacids found in samples collected from the pier in Gdansk, where recreation areas and beaches are located. Other authors (Veningerova et al., 1998; Rawn et al., 1999) detected very similar levels of chlorinated phenols and phenoxyacid herbicides. Phenoxyacids could possibly originate due to the leaching processes from surrounding agricultural area while chlorophenols might be present because they come from the degradation processes of phenoxyacid herbicides as well as industrial activity. Seasonal variations in their concentration confirm, that degradation is significant source of chlorophenols presence in seawater samples (Kot-Wasik et al., 2004). In general five times higher concentrations of phenoxyacids were detected in the spring period when these herbicides are applied in agriculture. Significantly higher concentrations of chlorophenols are also evident in spring compared with
3.3. Volatile organohalogen compounds (VOX) The results obtained for VOX are summarised and shown in Fig. 3, where a continuous decrease in VOX content in seawaters of the Gulf of Gda nsk is clearly demonstrated. Comparison of our results with data published elsewhere demonstrates that the concentra-
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Fig. 2. Annual average concentrations of VOC (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Gdynia, (d) Vistula.
autumn, which suggests that degradation processes are the sources of phenol derivates rather that human activity. According to Juhler et al. (2001) and Pozo et al. (2001) the main potential metabolites of phenoxyacids are chlorophenols. 3.5. Polycyclic aromatic hydrocarbons (PAHs) Concentrations for PAHs in waters collected along the coastal zone of the Gulf of Gda nsk are illustrated in Fig. 5. The aromatic hydrocarbons were divided into three groups: low molecular weight 128–178 g/mol (2–3 rings) (Fig. 5(1)) medium molecular weight 202–228 g/
mol (4 rings) (Fig. 5(2)) and high molecular weight 252– 278 g/mol (5–6 rings) (Fig. 5(3)). Generally, PAHs were determined the ng dm3 level and the determined compounds were naphthalene, phenanthrene, benzo(b)fluoranthene, anthracene. In case of low molecular weight PAHs their concentration varied from a few ng dm3 recorded in 1996 up to hundreds ng dm3 observed in 1998. Levels of moderate PAHs were also lower in 1996 with increasing tendency up to 1999 year. High molecular weight aromatic hydrocarbons were present at significantly lower concentrations with the exception of 1999, when values were always higher than either before or after. In case of
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Fig. 3. Annual average concentrations of VOX (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Gdynia, (d) Vistula.
the coastal waters of the Gulf of Gda nsk, the probable source is the neighbouring location of petroleum refinery and, possibly, car and ship transportation, which increases year by year, especially during summer period. Similar PAH concentrations were obtained by other authors, although it should be stressed that a direct comparison with literature data is difficult due to differences in the phase and the compounds considered in each study. The dissolved PAHs content in waters from
off-shore of Barcelona were 1800 pg dm3 . PAHs in the dissolved phase were found up to 30 and 50 ng dm3 in summer and winter, respectively, which is comparable with data obtained for the coastal waters of the Gulf of Gda nsk. 3.6. Polychlorinated biphenyls (PCBs) Content of PCBs in seawater samples in the area of the coastal zone of the Gulf of Gda nsk has been
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Fig. 4. Seasonal changes in the concentration (lg dm3 ) of chlorophenols (a and b) and phenoxyacids (c and d). Data for seawater samples collected in spring period are followed by data collected for autumn period.
estimated at low ppt level with some extraordinary exceptions. Detailed data are illustrated in Fig. 6. Within the previous 8 years of measurement of PCBs did not exceed few ng dm3 , with the exception of 1999, when all samples had extraordinarily high concentrations of PCBs. Higher concentrations of PCBs in open sea (Władysławowo) and in Gdynia and in Kiezmark suggest local pollution sources. Also, samples collected in Gdynia in 1997 and 1998 had PCBs at relatively
high concentrations in comparison with other times. In water, PCBs can exist either in the truly dissolved phase or adsorbed to suspended particles. Although the water solubility of PCBs is low, the total amount of PCBs in water can be elevated due to the presence of suspended particles with adsorbed PCBs. Since it is well known, that PCBs are poorly soluble in water and they have the tendency to accumulate in sediments and fatty tissues of fish, shellfish and seals. Even low
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Fig. 5. Annual average concentrations of PAHs (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Gdynia, (d) Vistula.
concentrations PCBs may cause in future damage in animals and, therefore, should be monitored continuously. According to data published by Renk (1993) relatively high concentrations of PCBs are observed in sediments collected from the Gda nsk Deep and in the Gulf of Gda nsk. Total content of PCBs in these sediments varies from hundred ng g1 up to hundreds of lg g1 , which clearly demonstrates sorption ability
of these compounds. Because of the fact that algae seems to have an significant role in the transport and distribution of PCBs, a high correlation of PCBs with chlorophyll a derivatives (products of zooplankton grazing) observed by other authors (Green and Knutzen, 2003) indicates that PCBs are ingested by zooplankton with phytoplankton and then exuded with fecal pellets. Eutrophication is a basic problem of the Baltic, hence probable that living and decomposed algae
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Fig. 5 (continued)
might have a decisive influence upon the geochemistry of PCBs. In the Baltic PCBs were determined first in animal tissues (fish, molluscs, birds) (HELCOM, 1996) and some of these values were alarmingly high (Falandysz et al., 1999). There are only few data available for PCB concentrations in water (HELCOM, 1996; Schlultz-Bull et al., 1995) and sediments of the Baltic Sea also have not been intensively studied (Parttila and Haahti, 1986; Van Bavel et al., 1996). Data for sediments of the Polish southern Baltic zone are scarce and indicate very low PCB concentrations.
4. Conclusions The results obtained during monitoring of the state of the Gulf of Gda nsk not show very high pollution levels in coastal waters by volatile and semi-volatile organic pollutants, such as VOC, VOX, chlorophenols, phenoxacids, PCBs and PAHs. The present state of the Gulf of Gda nsk––in case of the organic pollutants, specially those belonging to the persistent organic pollutant class––is certainly affected mostly by the human activity. Amounts of pollutants discharged via either rivers or atmosphere should be controlled and limited in the
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Fig. 5 (continued)
future in order to keep our seashore line in good condition. In view of the fact that degradation processes of the environment (also in the area of the Gulf of Gda nsk) are continuous and long-term development there is a necessity of a permanent control and improvement of the conditions of the environment. This is of vital importance for the future survival of the Baltic. The methods, which have been proposed and applied, were successfully used for the determination of organic compound in seawater samples and can be applied by any other analysts.
Acknowledgements The authors are grateful to Michael Maybeck (University in Paris, France) for valuable discussion in the preparation of this paper. M. Biziuk and B. Zukowska are kindly thanked for co-ordination of sampling and collection of data. A. Wasik prepared the map. The authors gratefully acknowledge all members of the Department of Analytical Chemistry (Gda nsk University of Technology) and Ph.D. Students are for GC and HPLC analyses of samples. This study was realised and
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Fig. 6. Annual average concentrations of PCBs (ng dm3 ) in the Gulf of Gda nsk and the Vistula River water in (a) Hel, (b) Władysławowo, (c) Orłowo, (d) Kiezmark.
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