Science of the Total Environment, The (v.366, #1)

Mine tailings are a characteristic of landscapes where mineral extraction has occurred. These tailings usually contain high heavy metal concentrations and have low fertility. In arid and semiarid zones, erosion may be an additional problem. The removal of these tailings is often impractical due to their large volumes. Therefore, a need exists to develop in situ low cost technologies to effect surface stabilization. The use of vegetation can be an attractive option, since there are some native plant species that can colonize parts of these polluted sites unaided. Some edaphic factors were investigated, including heavy metal concentrations, in three mine tailings from a semiarid mining zone in Southeast Spain. High total metal concentrations were found: 5000–8000 mg/kg for lead and 7600–12 300 mg/kg for zinc. Two of these mine tailings had pH values between 6 and 7, while the other was acidic, with a pH of 2.5. Metal solubility was pH dependent, with more than 10% of the total zinc soluble in the acid substrate and less than 1% in the neutral substrates. The metal concentrations (copper, lead and zinc) in shoots of native vegetation colonizing in these sites were studied. No species of hyperaccumulators were found. The highest concentrations were found in Zygophyllum fabago, with 530 mg/kg zinc, Helichrysum decumbens with 390 mg/kg lead, and Tamarix sp. with 11 mg/kg copper. An analysis of the rhizospheric soil of these plants indicated that Lygeum spartum grew in pH 3 soil and had low metal concentration in shoots (40 mg/kg zinc and 41 mg/kg lead).
Keywords: Mine tailings; Heavy metals; Phytostabilization; Semiarid climate;

Remediation of bromate-contaminated groundwater in an ex situ fixed-film bioreactor by R. Butler; S. Ehrenberg; A.R. Godley; R. Lake; L. Lytton; E. Cartmell (12-20).
Use of a pilot-scale fixed-film bioreactor was investigated for remediation of bromate contamination within groundwater. Bromate reduction with stoichiometric production of bromide was observed, providing supporting evidence for complete reduction of bromate with no production of stable intermediates. Reduction of 87–90% bromate from an influent concentration of 1.1 mg L− 1 was observed with retention times of 40–80 h. Lower retention times led to decreases in bromate reduction capability, with 11.5% removal at a 10 h retention time. Nitrate reduction of 76–99% from a 30.7 mg L− 1 as NO3 influent was observed at retention times of 10–80 h, although an increase in nitrite production to 2.7 mg L− 1 occurred with a 10 h retention time. Backwashing was not required, with the large plastic packing media able to accommodate biomass accumulation without decreases in operational efficiency. This study has provided proof of concept and demonstrated the potential of biological bromate reduction by fixed-film processes for remediation of a bromate contaminated groundwater source.
Keywords: Bromate; Bromide; Bioreactor; Fixed-film; Groundwater; Pilot-scale;

In Finland, shooting ranges are among the most common activities causing soil contamination. According to our study based on questionnaires and previous regional surveys, the total number of Finnish outdoor shooting ranges is between 2000 and 2500. Most of the ranges are small and only ca. 5% exceed 20 ha. Almost a third of the ranges can cause a groundwater pollution risk, while only few cause an immediate health risk. In the first instance, 50–60 shooting ranges identified as being high-risk areas should be investigated in detail. At present, the risk management options at Finnish shooting ranges are very limited. Hence, soil excavation combined with disposal is the most common remediation technique. Some of the remediation methods used in other countries have been proven unsuitable in Finnish conditions. Therefore, new, feasible, cost-effective and economical remediation technologies are needed. To exclude future contamination, a total ban of lead shot would be the most effective way.
Keywords: Shooting range; Lead; Contamination; Survey; Risk management;

Radon is a naturally occurring radioactive gas, high levels of which are associated with geological formations such as those found in Northamptonshire and North Oxfordshire in the UK. The UK's National Radiological Protection Board have designated both districts as radon Affected Areas. Radiation levels due to radon, therefore, exceed 200 Bq m− 3, the UK's domestic Action Level, in over one percent of domestic properties.Because of radon's radioactivity, exposure to the gas can potentially cause lung cancer, and has been linked to some 2000 deaths a year in the UK. Consequently, when radiation levels exceed the Action Level, remediation against radon's effects is recommended to householders.This study examines the cost-effectiveness of remediation measures in Northamptonshire and North Oxfordshire by estimating cost per quality-adjusted life-year gained in four Primary Care Trusts, organisations that play a key public health policy role in the UK's National Health Service. The study is the first to apply this approach to estimating the cost-effectiveness of radon remediation programmes.Central estimates of cost per quality-adjusted life-year in the four Primary Care Trusts range from £6143 to £10 323. These values, when assessed against generally accepted criteria, suggest the remediation programmes in the trusts were cost-effective. Policy suggestions based on the estimates, and designed to improve cost-effectiveness further, are proposed for the four Primary Care Trusts and the UK's National Health Service.
Keywords: Radon remediation; Lung cancer; Primary Care Trusts; Cost-effectiveness;

Variability of total exposure to PM2.5 related to indoor and outdoor pollution sources by Wieslaw A. Jedrychowski; Frederica P. Perera; Agnieszka Pac; Ryszard Jacek; Robin M. Whyatt; John D. Spengler; Thomas S. Dumyahn; Elzbieta Sochacka-Tatara (47-54).
The study is a part of an ongoing prospective cohort study on the relationship between the exposure to environmental factors during pregnancy and birth outcomes and health of newborns. We have measured personal PM2.5 level in the group of 407 non-smoking pregnant women during the 2nd trimester of pregnancy. On average, the participants from the city center were exposed to higher exposure than those from the outer city area (GM = 42.0 μg/m3, 95% CI: 36.8–48.0 vs. 35.8 μg/m3, 95% CI: 33.5–38.2 μg/m3). More than 20% of study subjects were affected by high level of PM2.5 pollution (above 65 μg/m3). PM2.5 concentrations were higher during the heating season (GM = 43.4 μg/m3, 95% CI: 40.1–46.9 μg/m3) compared to non-heating season (GM = 29.8 μg/m3, 95% CI: 27.5–32.2 μg/m3). Out of all potential outdoor air pollution sources (high traffic density, bus depot, waste incinerator, industry etc.) considered in the bivariate analysis, only the proximity of industrial plant showed significant impact on the personal exposure (GM = 54.3 μg/m3, 95% CI: 39.4–74.8 μg/m3) compared with corresponding figure for those who did not declare living near the industrial premises (GM = 36.2 μg/m3, 95% CI: 34.1–38.4 μg/m3). The subjects declaring high exposure to ETS (> 10 cigarettes daily) have shown very high level of personal exposure (GM = 88.8 μg/m3, 95% CI: 73.9–106.7 μg/m3) compared with lower ETS exposure (≤ 10 cigarettes) (GM = 46.3 μg/m3, 95% CI: 40.0–53.5 μg/m3) and no-ETS exposure group (GM = 33.9 μg/m3, 95% CI: 31.8–36.1 μg/m3). The contribution of the background ambient PM10 level was very strong determinant of the total personal exposure to PM2.5 and it explained about 31% of variance between the subjects followed by environmental tobacco smoke (10%), home heating by coal/wood stoves (2%), other types of heating (2%) and the industrial plant localization in the proximity of household (1%).
Keywords: Personal exposure to fine particles; Seasonality; Outdoor; Indoor sources;

A case study of personal exposure to nitrogen dioxide using a new high sensitive diffusive sampler by A. Piechocki-Minguy; H. Plaisance; C. Schadkowski; I. Sagnier; J.Y. Saison; J.C. Galloo; R. Guillermo (55-64).
Personal NO2 exposure measurements were achieved during two campaigns in a large northern France city. These campaigns were following an innovating approach based on sequential exposure measurements by diffusive samplers distinguishing four categories of microenvironments (“home”, “other indoor places”, “transport” and “outdoors”). The objective of these campaigns was to obtain NO2 personal exposure data in different microenvironments and to examine the determinants of personal exposure to this pollutant. Each campaign comprised two 24-h sampling periods: one during a working day and the second during the weekend. The average total NO2 personal exposure ranged from 17 μg m− 3 for the summer weekend samplings to 38 μg m− 3 for the winter weekday samplings. The highest levels were found in transports and outdoors, the intermediate ones in other indoor places and the lowest in homes. Despite their weak levels, indoor environments contributed for more than 78% to total NO2 personal exposure because of more time spent in these living places. A Multiple Correspondence Analysis (MCA) highlighted the determinants of NO2 personal exposure in the “home” and “transport” microenvironments. This led to a classification of NO2 personal exposure levels according to different means of transport: from the lowest to the highest exposure levels, train, tramway or underground, bicycle, car or motorcycle. In homes, the rise of NO2 personal exposures is mainly due to the use of gas stoves and gas heating and the absence of automatic airing system. A classification of NO2 personal exposure levels was set up according to the characteristics of homes. An analysis of correlations between the home NO2 personal exposures and outdoor concentrations measured by fixed ambient air monitoring stations showed weak relations suggesting that the data of these stations are poor predictors of NO2 personal exposures in homes.
Keywords: Nitrogen dioxide; Sequential measurements; Microenvironments; Personal exposure determinants; Passive sampling; Diffusive sampler;

The use of population-level indices to estimate individual exposures is an important limitation of previous epidemiologic studies of disinfection by-products (DBPs). We examined exposure misclassification resulting from the use of system average DBP concentrations to estimate individual-level exposures. Data were simulated (n  = 1000 iterations) for 100 subjects across 10 water systems based on the following assumptions: DBP concentrations ranged from 0–99 μg/L with limited intra-system variability; water intake ranged from 0.5–2.5 L/day; 20% of subjects used bottled water exclusively; 20% of subjects used filtered tap water exclusively; DBP concentrations were reduced by 50% or 90% following filtration. DBP exposure percentiles were used to classify subjects into different exposure levels (e.g., low, intermediate, high and very high) for four classification approaches. Compared to estimates of DBP ingestion that considered daily consumption, source type (i.e., unfiltered tap, filtered tap, and bottled water), and filter efficiency (with 90% DBP removal), 48–62% of subjects were misclassified across one category based on system average concentrations. Average misclassification across at least two exposure categories (e.g., from high to low) ranged from 4–14%. The median classification strategy resulted in the least misclassification, and volume of water intake was the most influential modifier of ingestion exposures. These data illustrate the importance of individual water use information in minimizing exposure misclassification in epidemiologic studies of drinking water contaminants.
Keywords: Disinfection by-products; Trihalomethanes; Haloacetic acids; Exposure misclassification; Water consumption; Water intake;

Data about non-dietary exposure to different chemical classes of pesticides are scarce, especially in France. Our objective was to assess residential pesticide exposure of non-occupationally exposed adults, and to compare it with occupational exposure of subjects working indoors. Twenty unexposed persons, five gardeners, seven florists and nine veterinary workers living in Paris area were recruited. Nineteen residences, two greenhouses, three florist shops and three veterinary departments were then sampled. Thirty-eight insecticides, herbicides and fungicides were measured in indoor air with an air sampler for 24 h, and on hands by wiping them with isopropanol-wetted swabs. After extraction, samples were analysed by gas and high-performance liquid chromatography. Seventeen different pesticides were detected at least once in indoor air and twenty-one on the hands. An average of 4.2 ± 1.7 different pesticides was detected per indoor air sample. The organochlorines lindane, α-endosulfan and α-HCH were the most frequently detected compounds, in 97%, 69% and 38% of the samples, respectively. The organophosphates dichlorvos and fenthion, the carbamate propoxur and the herbicides atrazine and alachlor were detected in more than 20% of the air samples. Indoor air concentrations were often low, but could reach 200–300 ng/m3 in residences for atrazine and propoxur. Propoxur levels significantly differed between the air of veterinary places and other places (Kruskal–Wallis test, p  < 0.05) and dieldrin levels between residences and workplaces (p  < 0.05). There was a greater number of pesticides on hands than in air, with an average of 6.3 ± 3.3 different pesticides detected per sample, the most frequently detected being malathion, lindane and trifluralin, in more than 60% of the subjects. Maximal levels (up to 1000–3000 ng/hands) were observed either in the general population or in workers, depending on the pesticide. However, no significant difference was observed between workers and general population handwipe pesticide levels. As expected, gardeners were exposed to pesticides sprayed in greenhouses. Florists and veterinary workers, whose pesticide exposure had not been described until now, were also indirectly exposed to pesticides used for former pest control operations. Overall, general population was exposed to more various pesticides and at levels sometimes higher than in occupational places. The most frequent pesticides in residences were not the same as in US studies but levels were similar. These preliminary results need to be confirmed in a greater number of residences from different parts of the country, in order to better assess pesticide exposure of the general population and its influencing factors.
Keywords: Pesticides; Indoor air; Cutaneous exposure; Human exposure assessment; General population; Occupational exposure;

Excessive fluoride ingestion predominantly comes from drinking water sources. However, prevalence and severity of dental and skeletal fluorosis in northern Tanzania have been reported to be higher than would be expected from ingestion of fluoride through drinking water alone. This study aimed at investigating the contribution of “trona” (also locally known as magadi) a food additive, to the prevalence and severity of fluorosis in northern Tanzania. The study was carried out in four villages (Embaseni, Kitefu and Ngurdoto) in Maji ya Chai ward; and Nkoanekoli in Poli ward, in Arusha region, Tanzania. Analysis of fluoride concentrations was carried out in drinking water sources as well as in magadi samples. Assessment of the prevalence of dental fluorosis using Dean's Index Method was carried out for a population of 2217 pupils in four primary schools located in the case study area. Fluoride concentration in drinking water sources was found to range from 1.7 to 11.3 mg/l, while the concentration in magadi samples in case study villages were in the range of 0.21 to 0.9 mg/g. Total fluoride ingestion through magadi and water were established to be 11.74 mg/person/day in Embaseni, 36.1 mg/person/day in Ngurdoto, 10.88 mg/person/day in Kitefu and 5.7 mg/person/day in Nkoanekoli villages. Levels of total fluoride ingestion were directly correlated with Community Fluorosis Index (CFI) values, which were found to be 3.32 (in Embaseni), 3.67 (in Ngurdoto), 2.2 (in Kitefu) and 1.47 (in Nkoanekoli). The village with the highest fluoride consumption rate showed the highest CFI as well. High levels of fluoride concentrations in magadi suggest that excessive fluorosis in northern Tanzania may be due to the use of magadi in food preparations.
Keywords: CFI; Dental and skeletal fluorosis; Magadi; Northern Tanzania; Trona;

Elevated blood selenium levels in the Brazilian Amazon by Mélanie Lemire; Donna Mergler; Myriam Fillion; Carlos José Sousa Passos; Jean Rémy Davée Guimarães; Robert Davidson; Marc Lucotte (101-111).
Contaminated fish poses a difficult challenge throughout the world, on the one hand, fish is a very nutritious food source, while on the other hand it accumulates many toxic substances, including mercury (Hg). As part of our efforts in the Brazilian Amazon to maximize nutritional input from fish consumption, a dietary mainstay, and minimize toxic risk, we have been studying the role of selenium (Se), an essential element, that may influence the distribution of Hg in the body and influence Hg neurotoxicity. Se, which is naturally present in the soil, is ingested through consumption of various foods, notably fish, mammals and certain plants. The objectives of the present study were: (i) evaluate whole blood Se (B-Se) and Hg (B-Hg); (ii) characterize B-Se variations with respect to socio-demographic and dietary variables; and (iii) examine the relation between B-Se and B-Hg. A total of 236 persons from six riparian communities of the Tapajós River Basin, a tributary of the Amazon, participated in this study. Whole blood Se and Hg were measured and interview administered questionnaires were used to obtain data on socio-demographic variable, smoking and drinking habits, and fish and fruit consumption. The results show that B-Se are in the upper normal range (median = 284.3 μg/L, range = 142.1–2029.3 μg/L). No individuals presented B-Se deficiency, but 9 participants from the same extended family had relatively high B-Se levels, potentially a threat to their health. B-Se varied between communities, was significantly higher among alcohol drinkers and farmers, but not associated with age, sex or tobacco consumption. A significant positive relation between B-Se and B-Hg was noted, independently of the overall fish consumption. B-Se increased with consumption of Peacock bass (Cichla sp.), a piscivorous fish species, and coconut pulp (Cocos nucifera L.). The B-Se intercommunity variations may reflect geographic differences in local soil Se levels as well as traditional land use practices in the different ecosystems of the Tapajós River Basin. In this population with relatively high exposure to Hg, Se may play an important role. Further studies should examine, in this region, the sources of Se, its transmission through the terrestrial and aquatic ecosystem and its role with respect to human health.
Keywords: Selenium; Mercury; Blood; Geographic differences; Fish and fruit consumption;

To assess how the human exposure to environmental carcinogenic polycyclic aromatic hydrocarbons (PAHs) pollution sources generated from industrial, traffic and rural settings, we present a probabilistic risk model, appraised with reported empirical data. A probabilistic risk assessment framework is integrated with the potency equivalence factors (PEFs), age group-specific occupancy probability and the incremental lifetime cancer risk (ILCR) approaches to quantitatively estimate the exposure risk for three age groups of adults, children, and infants. The benzo[a]pyrene equivalents based PAH concentrations in rural, traffic, and industrial areas associated with age group-specific occupancy probability at different environmental settings are used to calculate daily exposure level through inhalation and dermal contact pathways. Risk analysis indicates that the inhalation-ILCR and dermal contact-ILCR values for adults follow a lognormal distribution with geometric mean 1.04 × 10− 4 and 3.85 × 10− 5 and geometric standard deviation 2.10 and 2.75, respectively, indicating high potential cancer risk; whereas for the infants the risk values are less than 10− 6, indicating no significant cancer risk. Sensitivity analysis indicates that the input variables of cancer slope factor and daily inhalation exposure level have the greater impact than that of body weight on the inhalation-ILCR; whereas for the dermal-ILCR, particle-bound PAH-to-skin adherence factor and daily dermal exposure level have the significant influence than that of body weight.
Keywords: Polycyclic aromatic hydrocarbons; Benzo[a]pyrene; Potency equivalency factor; Health risk assessment; Environmental pollution;

Hospital indoor PM10/PM2.5 and associated trace elements in Guangzhou, China by Xinhua Wang; Xinhui Bi; Guoying Sheng; Jiamo Fu (124-135).
PM10 and PM2.5 samples were collected in the indoor environments of four hospitals and their adjacent outdoor environments in Guangzhou, China during the summertime. The concentrations of 18 target elements in particles were also quantified. The results showed that indoor PM2.5 levels with an average of 99 μg m− 3 were significantly higher than outdoor PM2.5 standard of 65 μg m− 3 recommended by USEPA [United States Environmental Protection Agency. Office of Air and Radiation, Office of Air Quality Planning and Standards, Fact Sheet. EPA's Revised Particulate Matter Standards, 17, July 1997] and PM2.5 constituted a large fraction of indoor respirable particles (PM10) by an average of 78% in four hospitals. High correlation between PM2.5 and PM10 (R 2 of 0.87 for indoors and 0.90 for outdoors) suggested that PM2.5 and PM10 came from similar particulate emission sources. The indoor particulate levels were correlated with the corresponding outdoors (R 2 of 0.78 for PM2.5 and 0.67 for PM10), demonstrating that outdoor infiltration could lead to direct transportation into indoors. In addition to outdoor infiltration, human activities and ventilation types could also influence indoor particulate levels in four hospitals. Total target elements accounted for 3.18–5.56% of PM2.5 and 4.38–9.20% of PM10 by mass, respectively. Na, Al, Ca, Fe, Mg, Mn and Ti were found in the coarse particles, while K, V, Cr, Ni, Cu, Zn, Cd, Sn, Pb, As and Se existed more in the fine particles. The average indoor concentrations of total elements were lower than those measured outdoors, suggesting that indoor elements originated mainly from outdoor emission sources. Enrichment factors (EF) for trace element were calculated to show that elements of anthropogenic origins (Zn, Pb, As, Se, V, Ni, Cu and Cd) were highly enriched with respect to crustal composition (Al, Fe, Ca, Ti and Mn). Factor analysis was used to identify possible pollution source-types, namely street dust, road traffic and combustion processes.
Keywords: Hospital; PM10 and PM2.5; Trace elements; Guangzhou;

In situ soil treatment using phosphoric acid (H3PO4) may be an effective remedial technology for immobilizing soil Pb and reducing Pb risk to human health and ecosystem. The treatment efficacy of three H3PO4 application methods was assessed in a smelter-contaminated urban soil located in the Jasper County Superfund Site, Missouri. Soil, with an average of 3529 mg Pb kg− 1 and in the 2- by 4-m plot size, was treated with H3PO4 at a rate of 10 g P kg− 1 in four replicates by each of three methods: rototilling; surface application; pressure injection. Three soil cores, 2.5-cm diameter and 30-cm long, were taken from each plot before and 90 days after treatment and analyzed for soluble P, bioaccessible Pb and solid-Pb speciation. Applications of H3PO4 induced the heterogeneity of soluble P in soil, with the highest concentrations in the surface. Three application methods mixed the H3PO4 more effectively in the horizontals than the verticals of treated soil zone. The H3PO4 applications significantly reduced Pb bioaccessibility in the soil, which was influenced by the concentrations of soil soluble P and solid-Pb species. The risk reductions of soil Pb were achieved by formation of pyromorphites or pyromorphite-like minerals. The rototilling appears to be the most effective treatment method in context of the homogeneity of soluble P and the reduction of Pb bioaccessibility in treated soil.
Keywords: Soil lead; Phosphate treatment; In situ immobilization; Soil remediation;

Manganese concentrations in the air of the Montreal (Canada) subway in relation to surface automobile traffic density by Nacéra Boudia; Renée Halley; Greg Kennedy; Jean Lambert; Lise Gareau; Joseph Zayed (143-147).
Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn), used since 1976 in Canadian gasoline as an octane enhancer. Its combustion leads to the emission of Mn particles. Several studies carried out by our research group have established a correlation between atmospheric Mn concentrations and automobile traffic density, suggesting that MMT in gasoline could play a significant role. This study aims to measure Mn concentrations in the air of the underground subway in Montreal (Canada) and to examine the relation with nearby surface automobile traffic density and, by extension, with the use of MMT in gasoline. Three subway stations were chosen for their location in different microenvironments with different traffic densities. Respirable (MnR < 5 μm) and total Mn (MnT) were sampled over two weeks, 5 days/week, 12 h/day. For the station located in the lower traffic density area, relatively low levels of MnR and MnT were found, with averages of 0.018 and 0.032 μg/m3, respectively. These concentrations are within the range of the background levels in Montreal. For the other two stations, the average concentrations of MnR were twice as high and exceeded the US EPA reference concentration of 0.05 μg/m3. Although there may be several sources of Mn from different components of the subway structure and vehicles, no correlation was found between subway traffic and atmospheric Mn in the subway. Since the air in the underground subway is pumped directly from outside without filtration, our findings strongly suggest that the combustion of MMT in automobiles is an important factor.
Keywords: Manganese; Subway; Traffic density; Respirable particles; MMT sources;

In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus pesticide chlorpyrifos, whole and decapsulated cysts have been exposed to 10 mg L− 1 chlorpyrifos in sea water during hydration and hatching phase, separately. The concentration of chlorpyrifos in capsulated and decapsulated cysts after exposure has been determined in order to elucidate the efficacy of chorion as protection to the embryo.The results obtained demonstrate the ability of the cysts chorion to obstruct the pass of chlorpyrifos molecules through this protection structure. Thus, the concentration of chlorpyrifos in exposed decapsulated cysts is higher than in exposed whole cysts. Moreover, after removing the chorion of exposed cysts, the concentration of chlorpyrifos in the embryo was lower than that of cysts exposed, what would demonstrate the retention of chlorpyrifos molecules by the shell.Hatching was not severely affected by exposure to the insecticide whereas survival at 44 h of the nauplii exposed to chlorpyrifos was significantly different from the controls. Survival of nauplii hatched from exposed decapsulated cysts was higher than that from those hatched from exposed whole cysts, probably because of the lower vitality of the latter, due to depletion of energy reserves during hatching.
Keywords: Artemia; Cysts chorion; Organophosphorus pesticides; Chlorpyrifos;

Allometric relationships in the bioconcentration of heavy metals by the edible tropical clam Gafrarium tumidum by L. Hédouin; M. Metian; J.-L. Teyssié; S.W. Fowler; R. Fichez; M. Warnau (154-163).
Although metal contamination is a problem of major concern in the lagoon of New Caledonia due to intense mining activities conducted on land, very little is known on the metal ecotoxicology of local marine organisms. The clam Gafrarium tumidum was investigated to assess its usefulness as a bioindicator species of metal contamination in this lagoon. More particularly, allometric relationships between metal accumulation and clam size were determined for five common metals in New Caledonian lagoon waters (Cd, Cr, Co, Zn and Ag) using a highly sensitive radiotracer technique. Experimental results showed that allometric relationships were dependent on the element and on the body compartment considered. As a rule, allometric relationships of metal concentration factor were more pronounced in shell than in soft parts. Significant relationships with clam size for Cd, Cr, Co and Zn followed inverse power functions. In contrast, the degree of Ag bioaccumulation was positively correlated with size. In view of the literature on Ag in bivalves, the latter observation suggests the occurrence of a specific detoxification mechanism (sequestration) that would be more efficient in old individuals. Overall, the experimental results indicate that the use of G. tumidum as a bioindicator in monitoring programmes requires selecting individuals of a specific size range in order to obtain comparable information about ambient metal levels. Since the size effect is greatest among smaller individuals, it is recommended to select clams with a shell width greater than 35 mm.
Keywords: Size effect; Metal; Uptake; Clam; Tropical lagoon; New Caledonia;

The aim of this work was to study, by an in toto immunohistochemical technique, the expression pattern of the heat shock protein, Hsp70, in the widely used bioindicator species Cloeon dipterum (Linnaeus 1761) (Ephemeroptera, Baetidae), living in a motorway retention pond. All sampling and measurements have been performed from March 2002 to March 2003. The water physicochemical analyses have revealed a large increase in Na+ and Cl concentrations after the de-icing road surface in winter related to motorway maintenance that correspond to an osmotic shock (from 3.1 to 105.7 mg L− 1 for Na+ and from 3.5 to 193.9 mg L− 1 for Cl). An expression of Hsp70 was observed in the chloride cells only during the osmotic shock. In contrast, the gill insertions were Hsp70 immunoreactive in specimens collected all along the year. For comparison, the expression of Hsp70 was investigated in specimens collected in a temporary pond. C. dipterum larvae living in this pond, not submitted to such osmotic shock, do not express Hsp70 neither in chloride cells nor in gill insertions. Likewise, the expression of Hsp70 was not detected in these structures during the drying period when the abiotic conditions become progressively stressful (elevation of temperature and anoxia). As chloride cells play a key role in osmoregulation, their functional integrity is crucial for the survival of the mayfly larvae in occasionally salty freshwaters. According to the well known protective role of the Hsp70 stress proteins, it is likely that the induction of Hsp70 may protect the chloride cells from osmotic shock injuries resulting from the increase in salinity. So, the Hsp70 induction in chloride cells is designed as a useful biomarker of osmotic shock. The in toto immunohistochemical detection of Hsp70 allows to characterize both the exposure situation and biological effects in target cells induced by stresses. This method could be used as a complementary qualitative approach in the biomarker actual concept. Finally, this investigation that combines this osmotic shock biomarker and this kind of bioindicator species would be a helpful tool for the monitoring of freshwater ecological systems.
Keywords: Chloride cell; Cloeon dipterum; Heat shock protein Hsp70; Osmotic shock; Mayfly larvae; Motorway retention pond;

Fish bile used to detect estrogenic substances in treated sewage water by Maria Pettersson; Margaretha Adolfsson-Erici; Jari Parkkonen; Lars Förlin; Lillemor Asplund (174-186).
Endocrine disrupting effects on fish associated with sewage treatment effluents have been demonstrated in several studies. To investigate if the effluents from two modern Swedish sewage treatment plants contained estrogenic substances, juvenile rainbow trout were exposed to sewage water before and after the last treatment step which is a sand filter. As a biomarker for estrogenic effect, vitellogenin was analysed in the blood plasma of the exposed fish. To identify substances possibly responsible for the effect, bile fluid from the exposed fish were analysed with GC/MS. Elevated levels of vitellogenin were only seen in the fish exposed at one of the sewage treatment plants, the one with shorter residence time in the biological treatment steps, which suggests that the residence time is of importance for the ability to reduce the amount of estrogenic substances in the sewage water. The highest elevation of vitellogenin was seen in the fish exposed to water before the sand filter, which indicates that the sand filter contributes to further reduction of estrogenic substances in the sewage water. In bile from the same group of fish, considerably higher concentrations of estrone, bisphenol A and 4-nonylphenol (4.0 μg/g bile, 23 μg/g bile and 24 μg/g bile, respectively) were observed compared to bile from control fish (< 0.04 μg/g bile, 0.21 μg/g bile, and 3.5 μg/g bile, respectively). The more potent steroidal estrogens were suggested to be major contributors to the observed estrogenic effect, although xenoestrogens were detected at higher concentrations in the bile fluid.
Keywords: Fish bile; Vitellogenin; Estrogen; Endocrine disrupters; Sewage effluent;

Baseline study of methane emission from anaerobic ponds of palm oil mill effluent treatment by Shahrakbah Yacob; Mohd Ali Hassan; Yoshihito Shirai; Minato Wakisaka; Sunderaj Subash (187-196).
The world currently obtains its energy from the fossil fuels such as oil, natural gas and coal. However, the international crisis in the Middle East, rapid depletion of fossil fuel reserves as well as climate change have driven the world towards renewable energy sources which are abundant, untapped and environmentally friendly. Malaysia has abundant biomass resources generated from the agricultural industry particularly the large commodity, palm oil. This paper will focus on palm oil mill effluent (POME) as the source of renewable energy from the generation of methane and establish the current methane emission from the anaerobic treatment facility. The emission was measured from two anaerobic ponds in Felda Serting Palm Oil Mill for 52 weeks. The results showed that the methane content was between 35.0% and 70.0% and biogas flow rate ranged between 0.5 and 2.4 L/min/m2. Total methane emission per anaerobic pond was 1043.1 kg/day. The total methane emission calculated from the two equations derived from relationships between methane emission and total carbon removal and POME discharged were comparable with field measurement. This study also revealed that anaerobic pond system is more efficient than open digesting tank system for POME treatment. Two main factors affecting the methane emission were mill activities and oil palm seasonal cropping.
Keywords: Greenhouse gases (GHG); Methane; Palm oil mill effluent (POME); Anaerobic ponds/lagoons;

Characterization of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the atmosphere of different workplaces of a sinter plant by Minliang Shih; Wen-Jhy Lee; Tung-Sheng Shih; Sheng-Lung Huang; Guo-Ping Chang-Chien; Lin-Chi Wang; Perng-Jy Tsai (197-205).
This study investigated concentrations, contents and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the workplaces of a sintering plant. Air samples were collected from the charging zone, the sintering zones of the sintering grate and the rough roll shredder, and the control room. The charging zone was found to have a higher total suspended particulate (TSP) but lower PCDD/F concentrations (= 4969 μg nm− 3 and 7.61 pg nm− 3, respectively) than the sintering zone (= 1422–1448 μg nm− 3 and 19.16–23.17 pg nm− 3, respectively). The TSP and PCDD/F concentrations were lowest in the control room (= 98 μg nm− 3 and 1.75 pg nm− 3, respectively). However, the above concentrations were within the range of a typical urban-industrial area. Quite similar PCDD/F contents were found in particles in the sintering zones and control room (= 11.72–14.30 and 15.85 ng g− 1, respectively) suggesting that the sintering zone and the control room are very similar. In both charging and sintering zones, 2,3,4,7,8-PeCDF contributed 40–60% to the total I-TEQ in both the gas phase and particle phase. However, in control room, both congeners 2,3,4,7,8-PeCDF and 2,3,7,8-TCDD were the main contributors; the later contributed 30% of the total I-TEQ in gas phase. In control room, the contribution of 2,3,7,8-TCDD to the total PCDD/F concentration in the gas phase greatly exceeded that in particle phase (= 5.5% and 0.8%, respectively). Therefore, solutions must be sought to avoid the transfer of not only the particle-phase but also the gas-phase PCDD/Fs from the sintering zone to the control room in the future.
Keywords: PCDD/Fs; Sinter plant; Content; Congener profile;

Plutonium in the air in Kurchatov, Kazakhstan by J. Lehto; S. Salminen; T. Jaakkola; I. Outola; S. Pulli; J. Paatero; M. Tarvainen; S. Ristonmaa; R. Zilliacus; A. Ossintsev; V. Larin (206-217).
Weekly air samples of 25 000 m3 volume were taken with two air samplers over a period of one year in 2000–2001 in the town of Kurchatov in Kazakhstan. For another three-month period in 2001, the samplers were run in the city of Astana, about 500 km west of Kurchatov. 137Cs, Pu and U concentrations were determined from the filters. Pu activities in Kurchatov varied in a 100-fold range; median 239,240Pu activities were 100 nBq/m3 and 238Pu activities 34 nBq/m3. The corresponding values for Astana were considerably lower: 29 and 9 nBq/m3, respectively, and in half of the filters the 238Pu activity was below the detection limit. Plutonium concentration correlated with the amount of dust retained on the filters only at the highest dust loads. Also no correlation between wind speed and the plutonium activity in the filters was observed. Thus, resuspension does not seem to be the mechanism responsible for the airborne plutonium. No clear seasonal variation of Pu air concentration was observed, though levels were somewhat elevated in February to April. There was no correlation between the plutonium and 137Cs concentrations. In most of the filters the cesium concentration was below the detection limit, but in those filters where it could be detected the cesium concentration was practically constant at 3.9 ± 1.6 μBq/m3. Dose estimation for the inhalation of the airborne plutonium gave a low value of 0.018 μSv/a for the inhabitants in Kurchatov, which is about a thousand times lower than the dose caused by the naturally occurring 210Po. Air parcel trajectory analysis indicated that the observed Pu activities in the air could not unambiguously be attributed to the most contaminated areas at the Semipalatinsk Test Site.
Keywords: Plutonium; Airborne; Doses; Resuspension; Semipalatinsk Test Site;

Calculation of odour emissions from aircraft engines at Copenhagen Airport by Morten Winther; Uffe Kousgaard; Arne Oxbøl (218-232).
In a new approach the odour emissions from aircraft engines at Copenhagen Airport are calculated using actual fuel flow and emission measurements (one main engine and one APU: Auxiliary Power Unit), odour panel results, engine specific data and aircraft operational data for seven busy days. The calculation principle assumes a linear relation between odour and HC emissions. Using a digitalisation of the aircraft movements in the airport area, the results are depicted on grid maps, clearly reflecting aircraft operational statistics as single flights or total activity during a whole day. The results clearly reflect the short-term temporal fluctuations of the emissions of odour (and exhaust gases). Aircraft operating at low engine thrust (taxiing, queuing and landing) have a total odour emission share of almost 98%, whereas the shares for the take off/climb out phases (2%) and APU usage (0.5%) are only marginal. In most hours of the day, the largest odour emissions occur, when the total amount of fuel burned during idle is high. However, significantly higher HC emissions for one specific engine cause considerable amounts of odour emissions during limited time periods. The experimentally derived odour emission factor of 57 OU/mg HC is within the range of 23 and 110 OU/mg HC used in other airport odour studies. The distribution of odour emission results between aircraft operational phases also correspond very well with the results for these other studies. The present study uses measurement data for a representative engine. However, the uncertainties become large when the experimental data is used to estimate the odour emissions for all aircraft engines. More experimental data is needed to increase inventory accuracy, and in terms of completeness it is recommended to make odour emission estimates also for engine start and the fuelling of aircraft at Copenhagen Airport in the future.
Keywords: Odour emissions; Aircraft engines; APU; HC; NO x ;

Emission of polycyclic aromatic hydrocarbons and lead during Chinese mid-autumn festival by Chung-Yih Kuo; Hong-Shen Lee; Jeang-Hung Lai (233-241).
The emission factors of total particulate polycyclic aromatic hydrocarbons (PAHs), Benzo(a)pyrene (BaP), BaP-equivalent doses (BaPeq) and Pb for burning three kinds of charcoal were investigated in this study: fast-lighting charcoal, Taiwanese, and Indonesian charcoal (the latter two of which are not fast-lighting). Compared to the burning of Taiwanese and Indonesian charcoal, the burning of fast-lighting charcoal can emit much larger amounts of total PAHs, BaPeq and Pb into the atmosphere. The emission factors of total PAHs, BaP and BaPeq for broiling meat were noticeably higher than those for broiling vegetables and non-fish seafood. When using Indonesian charcoal to broil meat, the total emission factors of particulate PAHs and BaP were about 15.7 and 0.39 mg/kg, respectively. The total amounts of particulate PAHs and Pb emitted from cookouts during Mid-Autumn Festival were 2881 and 120 g, respectively. Total PAHs and BaPeq in PM10 aerosols on Mid-Autumn Festival nights increased about 1.6 and 1.5 times, respectively, higher than those on non-festival nights. The mean concentration of Pb on the nights of Mid-Autumn Festival increases to about 2.8 times that of non-festival nights.
Keywords: Polycyclic aromatic hydrocarbons (PAHs); Lead (Pb); Charcoal burning; Food broiling; Emission factors;

Surface seawater samples were collected along the track of the R/V Hakuho-Maru cruise (KH-96-5) from Tokyo to the Southern Ocean. The 137Cs activities were determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas, the eastern Indian Ocean, the Bay of Bengal, the Andaman Sea, and the South China Sea. The 137Cs activities showed a wide variation with values ranging from 1.1 Bq m− 3 in the Antarctic Circumpolar Region of the Southern Ocean to 3 Bq m− 3 in the western North Pacific Ocean and the South China Sea. The latitudinal distributions of 137Cs activity were not reflective of that of the integrated deposition density of atmospheric global fallout. The removal rates of 137Cs from the surface waters were roughly estimated from the two data sets of Miyake et al. [Miyake Y, Saruhashi K, Sugimura Y, Kanazawa T, Hirose K. Contents of 137Cs, plutonium and americium isotopes in the Southern Ocean waters. Pap Meteorol Geophys 1988;39:95–113] and this study to be 0.016 yr− 1 in the Sulu and Indonesian Seas, 0.033 yr− 1 in the Bay of Bengal and Andaman Sea, and 0.029 yr− 1 in the South China Sea. These values were much lower than that in the coastal surface water of the western Northwest Pacific Ocean. This was likely due to less horizontal and vertical mixing of water masses and less scavenging. 239 + 240Pu activities and 240Pu /  239Pu atom ratios were also determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas and the South China Sea. The 240Pu /  239Pu atom ratios ranged from 0.199 ± 0.026 to 0.248 ± 0.027 on average, and were significantly higher than the global stratospheric fallout ratio of 0.18. The contributions of the North Pacific Proving Grounds close-in fallout Pu were estimated to be 20% for the western North Pacific Ocean, 39% for the Sulu and Indonesian Seas and 42% for the South China Sea by using the two end-member mixing model. The higher 240Pu /  239Pu atom ratios could be attributed to close-in fallout Pu delivered from the Enewetak and Bikini Atolls by ocean currents of branches of the North Equatorial Current to the Southeast Asian seas.
Keywords: 137Cs; 240Pu /  239Pu atom ratio; Surface seawaters; North Pacific Proving Grounds; Eastern Indian Ocean; Western North Pacific Ocean;

Unexpectedly high radioactivity burdens in ice-rafted sediments from the Canadian Arctic Archipelago by Glenn F. Cota; Lee W. Cooper; Dennis A. Darby; I.L. Larsen (253-261).
Unexpectedly high specific activities of 137Cs (1800–2000 Bq kg− 1 dry weight) have been detected in fine-grained sediments entrained in multi-year sea ice floes grounded in Resolute Bay near the center of the Northwest Passage through the Canadian Arctic Archipelago. These results are remarkable because: (1) the specific activities are about two orders of magnitude higher than average specific activities detected in previous studies of sea ice rafted sediments from the Arctic Ocean, (2) two independent observations of these unexpectedly high specific activities were made several years apart, (3) the sampling site is on the opposite side of the Arctic basin from potential radioactive sources such as disposal and weapons testing sites of the former Soviet Union and nuclear fuel reprocessing sites in western Europe, and (4) the closest compositional match to known geologic source regions is Banks Island, on the western edge of the Arctic Archipelago, although a smaller number of grains from one of the two samples were mineralogically matched to sediments in the Laptev Sea. Consequently, the sediments are probably not from a single distinct source and were likely mixed during sea ice transport. Coupled with previous observations of higher radionuclide specific activities in some sea ice rafted sediments relative to bottom sediments, these new observations indicate that comparatively high as well as variable radioactive contaminant burdens in ice rafted sediments must be common and geographically independent of proximity to known contaminant sources. The mechanisms that would facilitate these unexpected high radionuclide burdens in sea ice are not known and require additional study, as well as investigations of the implications for the transport and fate of contaminants in Arctic sea ice.
Keywords: Radioactive; 137Cs; Sediment; Sea ice; Arctic; Canada;

A comprehensive hydro-geochemical characterization was carried out in a petroleum-contaminated shallow sandy aquifer in South Africa. The results indicate the presence of a BTEX (benzene, toluene, ethylbenzene, and xylene) plume that has moved, although only slightly, along the regional hydraulic gradient from the spill site. Associated with the contaminant plume, spatial distribution pattern of terminal electron acceptors and metabolites indicates simultaneous occurrence of nitrate, manganese, iron and sulfate reductions resulting in overlapping redox zones within the aquifer. From the measured concentration of metabolic by-products, sulfate and iron reductions seem to be the dominant metabolic pathways, though.Incubation experiments conducted with hydrocarbon contaminated aquifer sediments and inherent microbial assemblages provide a sulfate reduction rate of 4272 nmol cm− 3 day− 1 and 96 nmol cm− 3 day− 1 for winter and summer, respectively. As oppose to this, iron reduction dominates in summer with measured respiration rate of 1414 nmol cm− 3 day− 1. In winter iron reduction was measured to be only 24 nmol cm−3 day− 1. Based on the dissimilatory iron and sulfate reduction rate measurements, we predict that at the aquifer site, intrinsic BTEX oxidation is primarily occurring in winter and is coupled to sulfate reduction. Although widespread in the aquifer, the contribution of iron reduction for the removal of aromatic monocyclic hydrocarbons is relatively minor.
Keywords: Anaerobic; BTEX; Degradation; Hydrocarbons; Iron reduction; Sulfate reduction;

Precipitation collected by a wet-only sampler (WP), precipitation collected by a filtering-type bulk sampler (BP), throughfall (TF), stemflow (SF), fog water (FW), and atmospheric aerosol and gases were collected at two sites with different site classifications: an urban site (Mt. Rokko) and a rural site (Mt. Awaga) to investigate canopy–atmosphere interactions and to study the chemistry of precipitation in forested areas located in different atmospheric conditions. Compared to those at the rural site, the monthly volume-weighted pH values at the urban site were not significantly (p  > 0.05) different for WP, higher (p  < 0.05) for BP, not significantly (p  >  0.05) different for TF, lower (p  < 0.01) for SF, and lower (p  < 0.01) for FW. The order of mean pH values at the urban site was FW < SF < WP < TF < BP. In contrast, the order at the rural site was FW < SF < BP < WP < TF. Concentrations of chemical species at the urban site were higher than those at the rural site in all samples and all chemical species. In particular, higher NO3 concentrations at the urban site were observed in all samples. The amount of dry deposition on leaves at the urban site was approximately 1.17 times larger than that at the rural site. The monthly net TF (= TF − BP) in autumn seemed to be larger than that in summer; this trend was remarkable in K+. The monthly NO3 deposition in the net TF was larger at the urban site than at other parameters and at the rural site. The concentrations of chemical species in aerosol and gases that were measured near the central part of Kobe City were ca. 3.4 times higher than those in the rural area. Mt. Rokko borders the central part of the city, which caused the concentrations at Mt. Rokko to be higher than those at Mt. Awaga. The deposition amounts at Mt. Rokko were larger than those at Mt. Awaga, which probably can be attributed to the higher concentrations of chemical species in atmospheric aerosol and gases.
Keywords: Aerosol; Bulk; Fog water; Gas; Stemflow; Site classification; Throughfall; Wet-only;

Metabolites from the biodegradation of di-ester plasticizers by Rhodococcus rhodochrous by Sandro Nalli; David G. Cooper; Jim A. Nicell (286-294).
The plasticizers di-2-ethylhexyl phthalate (DEHP) and di-2-ethylhexyl adipate (DEHA) are ubiquitous in the environment and undergo partial biodegradation in the presence of soil micro-organisms. The validity of a proposed pathway for the degradation of these plasticizers by Rhodococcus rhodochrous has been confirmed by the identification of 2-ethylhexanal in gas phase emissions. Complete analyses of the aqueous and gas phases were able to account for more than 98% of the 2-ethylhexanol component of the DEHA added at the beginning of a growth study. Of this, 25% was either 2-ethylhexanol or 2-ethylhexanal that had been stripped into the gas phase and, at most, only 2% of the 2-ethylhexanol component could have been removed by mineralization. It is concluded that plasticizers are of significant environmental concern due to the resistance of the metabolites to biodegradation and their known health impacts. Two of the metabolites are of added concern due to their volatility and their potential impact on indoor air quality.
Keywords: Biodegradation; Plasticizer; Metabolite; 2-ethylhexanol; 2-ethylhexanal;

Modeling of geochemical processes related to uranium mobilization in the groundwater of a uranium mine by P. Gómez; A. Garralón; B. Buil; Ma.J. Turrero; L. Sánchez; B. de la Cruz (295-309).
This paper describes the processes leading to uranium distribution in the groundwater of five boreholes near a restored uranium mine (dug in granite), and the environmental impact of restoration work in the discharge area. The groundwater uranium content varied from < 1 μg/L in reduced water far from the area of influence of the uranium ore-containing dyke, to 104 μg/L in a borehole hydraulically connected to the mine. These values, however, fail to reflect a chemical equilibrium between the water and the pure mineral phases. A model for the mobilization of uranium in this groundwater is therefore proposed. This involves the percolation of oxidized waters through the fractured granite, leading to the oxidation of pyrite and arsenopyrite and the precipitation of iron oxyhydroxides. This in turn leads to the dissolution of the primary pitchblende and, subsequently, the release of U(VI) species to the groundwater. These U(VI) species are retained by iron hydroxides. Secondary uranium species are eventually formed as reducing conditions are re-established due to water–rock interactions.
Keywords: Uranium retention; Groundwater; Geochemical modeling; Uranium mine; Granite;

Copper complexing properties of melanoidins and marine humic material by Marta Plavšić; Božena Ćosović; Cindy Lee (310-319).
Melanoidins, condensation products of sugars and amino acids, represent a key link in the transformation of polysaccharides to humic material in the marine environment. We investigated the complexing capacity of melanoidins that were prepared in deionized water and seawater and separated into different molecular mass fractions. The copper complexing properties of humic material isolated from marine lagoon sediments were determined for comparison. Melanoidins prepared using condensation times longer than two days exibit complexation properties towards copper ions that appear to depend on the basicity of the amino acid precursor and the molecular mass of the product. Pseudomelanoidins, prepared from glucose only, do not complex copper ions at all, regardless of the molecular mass. The highest copper complexing capacity value among melanoidins was measured for a glucose–lysine melanoidin with molecular mass fraction > 10 kD (LT  = 2.1 × 10− 7 molCu2+/L). Melanoidin prepared from glucose and glutamic acid > 10 kD was similar in complexing capacity to fulvic acid (1–20 kD molecular mass) isolated from lagoon sediments. The presence of calcium and magnesium ions and other macro and microconstituents in the seawater used to prepare melanoidins influences its complexing properties towards metal ions.
Keywords: Melanoidins; Humic matter; Copper ions; Complexation; Electrochemistry;

Mercury recovery in situ of four different dental amalgam separators by Lars D. Hylander; Anders Lindvall; Roland Uhrberg; Lars Gahnberg; Ulf Lindh (320-336).
Amalgam separators are used to physically remove dental amalgam from waste water in dental clinics. They are thereby supposed to reduce mercury (Hg) emissions to the municipal waste water system to acceptable levels. We here present results from a comparative study in situ of three amalgam separators available on the market, all with a claimed efficiency of 99% according to Danish and ISO protocols, and using sedimentation as the principle of separation. We also present corresponding data for an investigational prototype of an improved separator.The obtained efficiency of the three commercial separators is far below what is stated by the manufacturer and by authorities assumed to be the efficiency in clinical conditions. They reduced Hg emissions by 79 – 91%, leaving an average Hg content in outgoing waste water of 1.5 mg L− 1. However, the prototype separator participating in this study retained 99.9% of the waste water Hg emissions, leaving an average Hg content in outgoing waste water of 0.004 mg L− 1. Physical restrictions prohibit sedimentary type separators to recover the Hg fractions causing the largest damages in wastewater treatment plants. This fraction is not considered in the ISO protocol for testing amalgam separators, which therefore needs to be revised.Abolishing the use of dental amalgam and cleaning the tubing systems is the most efficient long-term solution to reduce Hg emissions from dental clinics. Until then, Hg emissions originating from placing, polishing or removing existing amalgam fillings, should be counteracted by the use of low-emission amalgam separators, already on the market or presently being developed for use alone or together with sedimentary type amalgam separators.
Keywords: Amalgam separator device; Mercury pollution; Mercury traps; Prevention; Recovery efficiency;

This study reports analyses of carbon and nitrogen content, and δ 15N and δ 13C in sediments of the Höggarnsfjärden Bay near Stockholm. Samples have been taken upstream, near, and downstream of a point source of processed leach water from a garbage dump. The surface sediment at the upstream and downstream sites has δ 15N and δ 13C close to the expected background of the area, even though a contribution from the leach water can be observed downstream of the point source. The sediment close to the outflow is strongly influenced by the carbon and nitrogen in the leach water.
Keywords: Nitrogen; Carbon; Stable isotopes; Sediment; Garbage dump; Stockholm archipelago;

The desorption kinetic of trace elements (Cd, Zn, Co, Mn, Fe, Ag, and Cs) associated with Loire river natural suspended particulate matter (SPM; 0.4–63 μm) was followed up on times varying from 0.5 h to 30 days, from SPM previously contaminated during 1 h, 24 h and 30 days. Long term sorption kinetics indicated that the difference between sorption occurring during the period 0–30 days (time investigated in this study) and the period 0–48 h (time often used for sorption experiments) ranges from few to 25% according to the element. Desorption kinetics show that, whatever the age of the complex formed during the sorption step, the release tends to equilibrium between complexed and dissolved elements equivalent to the equilibrium obtained for sorption after a given time. However, the time to get this equilibrium depends on the aging of the complex and on the element. All the above features indicate different types of complexes formation and strength of the binding according to the age of the complex and according to the element. Using a multi-compartmental model, simulating the transfer of metals between water and different types of particulate sites, the relationships between the parameters describing slow and rapid processes helped in explaining the “aging” effect observed.
Keywords: Sorption; Desorption; Trace metal; Aging effect; Kinetic model;

Evaluation of total lipids using enzymatic methods for the normalization of persistent organic pollutant levels in serum by Adrian Covaci; Stefan Voorspoels; Cathrine Thomsen; Bert van Bavel; Hugo Neels (361-366).
The human exposure to persistent organic pollutants (POPs) is conveniently assessed through analysis of blood serum or plasma and the POPs concentrations are traditionally expressed on a lipid weight basis. Enzymatic determinations of total lipid (TL) content in serum, which imply the measurement of individual lipid classes, such as triglycerides (TG), cholesterol (CHOL) and phospholipid (PL), use small amounts of serum/plasma (< 100 μl). These have also become a more precise and less laborious alternative for the gravimetric lipid determinations which were preferred in the past. However, PL are not routinely measured in most clinical laboratories and therefore, TL values are often predicted from formulas based on measurements of only TG and CHOL. In the present study, a large data set (n  = 483) from Belgian, Swedish and Norwegian populations was used to compute a new formula for TL [TL = 1.33   TG + 1.12   CHOL + 1.48 (g/l)] by means of multiple linear regression. A very good correlation (r  = 0.949, p  < 0.001) was found between TL values calculated with the proposed formula and TL values obtained by summation of TG, CHOL and PL. Statistically different values of TL were computed when different previously published formulas were compared, which can have a strong influence on the calculation of lipid-normalized concentrations of POPs. Nevertheless, TL values derived using a mathematical formula which includes only TG and CHOL will be less accurate than TL values obtained by summation of TG, CHOL and PL, which should be the calculation method of choice if PL measurements are available.
Keywords: Total lipids; Enzymatic measurements; Blood; Computed formula; Persistent organic pollutants;

Selenium accumulation patterns in lotic and lentic aquatic systems by Wendy E. Hillwalker; Paul C. Jepson; Kim A. Anderson (367-379).
Selenium (Se) concentrations in water column, sediment and insect compartments were measured over 3 years, in conjunction with selected physicochemical parameters, from lotic (flowing water) and lentic (standing water) sites within a single watershed in Utah, USA. There was evidence for steady-state concentrations of total [Se] in the insects, sediment and detritus, while there was no correlation between these concentrations and the concentration in surface water. Insect Se burden may therefore provide a more accurate measurement of food web accumulation risk than surface water Se concentration. The importance of organism-specific factors on Se transfer to higher trophic levels was revealed by the steady-state Se body burden within the same insect taxa occupying similar environmental compartments in both aquatic systems. Additionally, however, insect Se body burdens, even within similar taxa, were up to 7 times greater within the lentic compared with the lotic system, and site-specific biogeochemical processes are also likely to play a role in the pattern and level of Se accumulation between hydrogeochemically different aquatic systems occurring within the same watershed. Though a site-specific relationship was apparent between organic content and sediment and detritus Se concentrations, this factor did not account for insect Se accumulation differences between the lotic and lentic aquatic habitats. If carbon content is to be used as a site-specific predictor of Se accumulation potential, further investigations of it's influence on the food web accumulation rate of Se are required.
Keywords: Trophic; Temporal; Biogeochemical; Watershed; Benthic insects; Selenium;

A translocation experiment of red swamp crayfish (Procambarus clarkii) to different sites located in the River Guadiamar was performed in order to assess the ability of this species as bioindicator of heavy metal and metalloid contamination. Crayfish were placed in cages and exposed to polluted environment during either 6 or 12 days in the three sites with different concentration of contaminants. Their tissues (exoskeleton + gills, hepatopancreas and abdominal muscle) were dissected and analysed by ICP–MS to assess for concentration of Cd, Cu, Zn, Pb and As. Both exposure times result in significant bioaccumulation of some metals in crayfish tissues as compared to their concentration in the environment. According to overall metal concentration, crayfish tissues rank as follows: hepatopancreas/viscera > exoskeleton/gills > abdominal muscle. Essential metals for crayfish metabolism (Cu and Zn) are always found in high concentrations independently of their quantities in the environment because of the ability of crayfish to manipulate their levels for their own metabolic profit. Metals not involved in crayfish metabolism (Cd, Pb, As) tend to increase with increasing concentration in the surrounding environment and with longer exposure times. Thus crayfish could be used as bioindicator of these pollutants because their dose- and time-dependent accumulation may be reflective of the levels of non-essential metals present in contaminated wetlands. Future guidelines in plans for monitoring contamination on polluted Mediterranean rivers and wetlands should take into account the implementation of the incubation of crayfish during 6 days and their subsequent analyses of metal contents, as a routine.
Keywords: Biological indicator; Heavy metal contamination; As; Guadiamar River; Crayfish; Translocation experiment; Aznalcóllar mine spill;