Phytoplankton and water quality characterization: experiences from the Swedish large lakes Mälaren, Hjälmaren, Vättern and Vänern

Phytoplankton and environmental variables have been monitored in the large Swedish lakes M?laren, Hj?lmaren, V?ttern and V?nern since the 1960s. Measures to reduce phosphorus input and industrial waste products were taken during the 1970s. The phosphorus loading was then reduced by 90-95% resulting in a halving of the phosphorus concentrations in the most affected basins. The phytoplankton community reacted rapidly with decreased biomasses of cyanobacteria in summer as well as decreased biomasses of spring diatoms and cryptophycean flagellates. Other reactions were a contracted period of water-bloom, an increased taxon richness, an increased evenness in the biomass over the growth season, and a change in the species size structure within the phytoplankton community. Furthermore, the species richness in the large lakes is compared in relation to lake characteristics. A presentation of the occurrence of toxic cyanobacteria in the lakes is also given. Maximum-minimum values of 13-0.1 micrograms microcystin L-1 are established in connection with water-blooms in Hj?lmaren and M?laren. The use of phytoplankton as a monitoring variable to detect water-quality changes is outlined and assessment criteria are presented.     

The application of satellite remote sensing to coastal management in Singapore

This paper reviews the application of satellite remote sensing to management of Singapore's coastal environment. Remotely sensed data have been used for marine habitat mapping, water quality monitoring, ship and ship-wake detection, oil spill detection, red tide monitoring, and mapping of reclamation activities. While these applications clearly cover most of the range of opportunities for use of remotely sensed data in the coastal zone, there is still a need for more complete baseline studies of natural resources and habitats, and monitoring of the impacts of development on the coastal and marine environment. There is also a requirement for more management-oriented research and continued development and revision of the available datasets. Integration and exchange of information between management agencies and research groups is also an important aspect of sustainable management of Singapore's coastal environment and marine resources.     

Resistant sorption of in situ chlorobenzenes and a polychlorinated biphenyl in river Rhine suspended matter

The desorption kinetics of in situ chlorobenzenes (dichlorobenzenes, pentachlorobenzene and hexachlorobenzene) and 2,4,4^′-trichlorobiphenyl (PCB-28) were measured with a gas-purge technique for river Rhine suspended matter sampled in Lobith, The Netherlands. This suspended matter is the main source of sediment accumulation in lake Ketelmeer. In lake Ketelmeer sediment earlier observations showed that slow and very slow fractions dominate the desorption profile.

For the river Rhine suspended matter, only for PCB-28 a fast desorbing fraction of around 1.6% could be detected. The observed rate constants were on the average 0.2 h⁻¹ for fast desorption, 0.004 h⁻¹ for slow desorption, and 0.00022 h⁻¹ for very slow desorption. These values are in agreement with previous findings for the sediment from lake Ketelmeer and with available literature data on fast, slow, and very slow desorption kinetics.

The results from this study show the similarity of desorption profiles between river Rhine suspended matter, and the top layer sediment from lake Ketelmeer. This indicates that slow and very slow fractions are already present in material forming the top layer of lake Ketelmeer, and were not formed after deposition of this material in the lake. The absence of detectable fast fractions for most compounds could be caused by the absence of recent pollution of the suspended matter. But, the observations may also be explained by a rapid disappearance of compounds from the fast fraction due to a combination of a high affinity of very slow sites for these compounds, and their relatively high volatility.     

Baseline levels of PCDD/Fs in soil and herbage samples collected in the vicinity of a new hazardous waste incinerator in Catalonia,Spain

The construction in Constantí (Catalonia, Spain) of a new hazardous waste incinerator (HWI), which is the first one in Spain, finished in 1999. In order to determine the temporal variation (1996–1998) in the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in the vicinity of the new HWI, 40 soil and 40 herbage samples were collected (1998) at the same sampling points in which samples had been taken two years before (1996). Each sample was analyzed for PCDDs and PCDFs by high resolution gas chromatography/high resolution mass spectrometry. In the 1996 survey, PCDD/F concentrations in soils ranged from 0.13 to 24.20 ng I-TEQ/kg (d.m.), with median and mean values of 0.67 and 1.68 ng I-TEQ/kg (d.m.), respectively. In the present study, PCDD/F concentrations ranged from 0.12 to 17.20 ng I-TEQ/kg (d.m.), with a median value of 0.75 ng I-TEQ/kg (d.m.) and a mean value of 1.59 ng I-TEQ/kg (d.m.). In turn, in the present study PCDD/F concentrations in vegetation ranged from 0.14 to 2.01 ng I-TEQ/kg (d.m.) (median and mean values: 0.23 and 0.31 ng I-TEQ/kg, respectively), while in the 1996 survey PCDD/F concentrations ranged from 0.24 to 1.22 ng I-TEQ/kg (d.m.) (median and mean values: 0.53 and 0.61 ng I-TEQ/kg, respectively). According to the present (1998) and the previous (1996) levels of PCDD/Fs found in soils and vegetation, the area under potential influence of the new facility shows a rather low contamination by these compounds. The current results should be useful to establish the environmental impact of the HWI.     

Partitioning of polychlorinated biphenyls and hexachlorobenzene into human faeces

The dietary absorption of persistent lipophilic organic pollutants (PLOPs) in humans is believed to occur via partitioning of the chemical between the lumen and the wall of the digestive tract. As such, the partitioning properties of the lumen contents are a key factor governing absorption. In this study, the partitioning properties of faeces were measured for 11 polychlorinated biphenyls and hexachlorobenzene (HCB). Four volunteers participated in the study, each of them providing faeces from a normal diet and a vegetarian diet. The faeces/gas equilibrium partition coefficient K(FG) varied by over three orders of magnitude between the different compounds. A linear relationship between log K(FG) and log KOA, the octanol/air partition coefficient, was observed. The slope of the relationship was > 1, indicating that the solvent properties of faeces were less polar than those of octanol. For a given compound, KFG varied up to a factor of 2.8 between the individuals on a normal diet. The influence of the vegetarian diet on K(FG) was negligible for the two volunteers who simply deleted fish and animal products from their normal diet, but K(FG) increased on average by a factor of 2 in the two individuals who increased their consumption of less readily digestible whole grains and vegetables in their vegetarian diet. On the basis of K(FG), the fugacities in the faeces were calculated. They were found to be much lower than the fugacities in blood. It is hypothesised that this is due to a temporary decrease in the fugacity in the wall of the jejunum caused by absorption of dietary lipids that results in equilibration between the lumen contents and the wall of the digestive tract at a fugacity below that present in the blood and the rest of the body.     

Contaminant residues in seabird eggs from the Canadian Arctic. II. Spatial trends and evidence from stable isotopes for intercolony differences

Eggs of glaucous gulls (Larus hyperboreus), black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia) and black guillemots (Cepphus grylle) were collected from several sites throughout the Canadian Arctic. Samples were analyzed for organochlorines as well as mercury and selenium. Glaucous gulls breeding at sites in the High Arctic showed higher levels of organochlorine contamination than those in the western Low Arctic. This was likely due to dietary differences among colonies as suggested by stable isotope data, although different overwintering areas may also play a role. Levels of sigmaPCB, sigmaDDT, sigmaCHLOR, sigmaCBz and dieldrin were significantly lower in thick-billed murres from Prince Leopold Island in the High Arctic compared with colonies in the eastcrn Low Arctic. This difference was likely due to the combined effects of different atmospheric deposition patterns in the High and Low Arctic and different overwintering areas since murres from Prince Leopold Island may winter farther north than murres from the other colonies sampled. Eggs from colonies at higher latitudes generally contained higher concentrations of mercury. The trophic and dietary differences/similarities suggested by stable-nitrogen and carbon isotope data in this study were useful in explaining the spatial patterns of contaminant concentrations observed among colonies of seabirds such as the glaucous gull and the black-legged kittiwake where variation in latitudinal atmospheric deposition patterns and different overwintering grounds did not appear to be confounding factors.     

Tracking chlordane compositional and chiral profiles in soil and vegetation

The cycling of chlordane and other persistent organic pollutants through the environment must be comprehensively elucidated to assess adequately the human health risks posed from such contaminants. In this study the compositional and chiral profiles of weathered chlordane residues in the soil and vegetative compartments were investigated in order to provide details of the fate and transport of this persistent pesticide. Zucchini was planted in a greenhouse in three bays containing chlordane-contaminated soil. At harvest the vegetation and soil were extracted and analyzed for chlordane content using chiral gas chromatography/ion trap mass spectrometry. Both achiral and chiral chlordane components were quantified. The chlordane concentration in the rhizosphere (soil attached to roots) was significantly less than that in the bulk soil. However, the enantiomeric ratio of the chiral components and overall component ratios had changed little in the rhizosphere relative to the bulk soil. Significant levels of chlordane were detected in the vegetation, the amount varying in different plant tissues from a maximum in roots to a minimum in fruit. In addition to the chlordane concentration gradient in plant tissues, significant shifts in compositional profile, as indicated by the component ratios, and in chiral profile, as indicated by the enantiomeric ratio, of the contaminant were observed in the plant tissues. The data indicate that abiotic processes dominate the transport of the chlordane components through the soil to the plant. This is the first report of the effect of rapid biotic processes within the plant compartment on chlordane compositional and chiral profiles.     

EuroBionet: a pan-European biomonitoring network for urban air quality assessment

EuroBionet, the 'European Network for the Assessment of Air Quality by the Use of Bioindicator Plants', is an EU-funded cooperative project currently consisting of public authorities and scientific institutes from 12 cities in 8 countries. In 2000, the bioindicator plants tobacco (Nicotiana tabacum Bel W3), poplar (Populus nigra 'Brandaris'), spiderwort (Tradescantia sp. clone 4430), Italian rye grass (Lolium multiflorum italicum) and curly kale (Brassica oleracea acephala) were exposed to ambient air at 90 monitoring sites according to standardised methods. Visible injuries and growth parameters were assessed and the accumulation of toxic substances in leaves determined. The exposure of tobacco resulted in a gradient with low levels of ozone-induced foliar injury in N and NW Europe, and medium to high values in the southern and central regions. The results of heavy metal and sulphur analyses in rye grass samples generally showed low to very low sulphur and low to medium heavy metal concentrations in leaves. In some cities, however, local hot spots of heavy metal contamination were detected. Analyses of the PAH contents in curly kale leaves gave low to medium values, with locally elevated levels at traffic-exposed sites.     

Comparative study of the suitability of three lichen species to trace-element air monitoring

To investigate the suitability of three lichen species (Cetraria islandica, Evernia prunastri, and Ramalina farinacea) as transplants to trace-element air biomonitoring, they were exposed on substratum-free supports, from July 1996 until July 1997, in three European countries with different climates (Germany, Italy, Romania), at six sites with different types of air pollutants (two in each country). After 2, 4, 6, and 12 months of exposure, some portions of thallus were collected, prepared, and measured by instrumental neutron activation analysis (INAA) at the Institute of Physics and Nuclear Engineering in Bucharest and by energy dispersive X-ray fluorescence analysis (EDXRFA) at the University of Hohenheim in Stuttgart. Fifteen environmentally relevant elements: As, Br, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, S, Sb, V, and Zn were determined. The analytical results were compared statistically. To study the distribution of the trace-elements between the lichens and the lichen throughfall water inside a virtual column, the throughfall water was collected under the lichen transplants during 6 and 12 months. The dried residues were analysed by INAA at Bucharest. The accumulating capacity for all investigated species is evident. For a comparative evaluation, the initial element contents, the "accumulation factors" relative to the bulk deposition, the interspecies "calibration factors", and the "retention efficiencies", defined as ratios of the lichen enrichment to the sum of this enrichment and the content in the lichen throughfall water, were considered. These criteria attest the best suitability for Evernia prunastri, followed by Ramalina farinacea and Cetraria islandica.     

Development and calibration of epiphytic lichens as saltfall biomonitors--dry-deposition modelling

Blubber collected from beluga whales and ringed seals during subsistence hunts in the southern Baffin Island region of the Canadian Arctic were analysed for polychlorinated naphthalenes and eight planar PCB congeners (mono-ortho PCBs: 105, 114, 118 and 156; non-ortho PCBs: 77, 81, 126, 169). SigmaPCN (3-7 Cl) concentrations in blubber ranged from 35.9-383 pg/g (lipid weight; lw) in beluga and 35.4-71.3 pg/g (lw) in ringed seal. These represent the first measurements of PCNs in marine mammals in the Canadian Arctic, mammals which are an important part of the traditional diet of the indigenous population. SigmaCoplPCB concentrations were much higher, ranging from 15.5-317 ng/g (lw) in beluga whale blubber and 16.5-40.9 ng/g (lw) in ringed seal blubber. PCNs and coplanar PCBs both exhibit dioxin-like toxicity. Although average sigmaPCN concentrations were less than 1% of sigmaCoplPCBs, PCNs contribute up to 11% of TEQ relative to the coplanar PCBs based on TEFs determined by H4IIE enzyme assays.