Phytoplankton in a polluted subarctic lake before and after nutrient reduction

Phytoplankton and water chemistry were studied in a eutrophic subarctic Swedish lake before and after nutrient reduction. Pollution started in 1964 and the lake had received about 4.5 tons of phosphorus by the time the treatment plant was built in 1974. After that only 18–20 kg P yr^?1 entered the lake. Before nutrient reduction the phytoplankton consisted principally of three species, Dictyosphaerium pulchellum var. minutum, Chromulina cv. darlecarlica and Cryptomonas cv. ovata. Two years after the P-load was reduced Chlamydomonas spp and Mallomonas akrokomos predominated in the plankton and their dominance has been maintained during the period of study. Seasonal average phytoplankton biomass decreased from 11.2 g m^?3 in 1973 to 2.9 g m^?3 in 1980. Average seasonal total phosphorus concentrations decreased from 168 μgl^?1 in 1973 to 74 μgl^?1 in 1980. Average Secchi depth readings increased from 1.3 m in 1973 to 2.1 m in 1980. Blue-green algae never had any quantitative importance in the lake and no blooms were observed.     

Laboratory and field analysis of pentachlorophenol (PCP) accumulation by salmonids

Rainbow trout were fed diets containing 10–3000 μg kg^?1 pentachlorophenol (PCP) for up to 110 days to examine its accumulation. Fish fed the 10 μg kg^?1 diet maintained whole body levels of 2 μg kg^?1 PCP over the study period, while PCP levels in those fed the 3000 μg kg^?1 diet increased to 40 μg kg^?1 after 40 days, then decreased thereafter to 20 μg kg^?1 at the end of the study. The biological half-life ($\text{T}\text{1}\text{2}$) of PCP in trout was estimated to be approx. 7 days. PCP levels in six species of fish representing two trophic levels from Lake Ontario were also monitored, most species contained 1–10 μg kg^?1 PCP. The results of these and other studies would suggest PCP accumulation in fish is primarily through direct uptake from water rather than accumulation through the food-chain.     

Distribution of total mercury in the fishes of Lake Oahe

In 1971, a joint Federal-State survey was conducted to investigate the total mercury content of fish and sediment in Lake Oahe, South Dakota. Average total mercury concentration of 225 fish flesh samples was 0.27 mg kg⁻¹; game fish samples averaged 0.31 mg kg⁻¹ and nongame fish samples averaged 0.22 mg kg⁻¹. Frequency distributions of total mercury concentrations in the fish are presented by fish species and sampling location. Data include total mercury analyses of 43 sediment samples.     

Kinetics of dose-response relationship in the bimodal respiration of Colisa lalia (Hamilton-Buchanan) exposed to lindane (γ-BHC)

Acute bioassay tests were conducted with the organochlorine pesticide, lindane on Colisa lalia. LC50 and its 95% upper and lower confidence limits for different periods of exposure were determined. A toxicity curve was constructed from which is derived the lethal threshold concentration for Colisa to lindane. The fish were exposed to two selected concentrations viz., 0.1 and 0.37 mg 1^?1 for 96 and 6 h respectively and their behaviour and bimodal respiration were studied. Erratic behavioural responses were noticed at 0.37 mg 1^?1 whereas the response at 0.1 mg 1^?1 were orderly and adaptive. Total oxygen consumption of fish increased but the dependence on the type of respiration differed in the two concentrations, and this selective dependence at 0.1 mg 1^?1 is suggested to have survival value.     

Naturally Pb-contaminated soils in uranium and thorium anomaly

The paper reports an examination of the primary sources of stable lead (Pb) occurring in rocks and soils on dairy farms in the municipalities of Pedra and Venturosa in Pernambuco, Brazil. Lead in rock and soil was quantified by flame atomic absorption spectrophotometry. The Pb concentration in calcium silicate rock varied from 21 to 1124.00 mg.kg^?1 and soil varied from 18 to 96 mg.kg^?1. The lead concentration in granite rock varied from 6 to 440 mg.kg^?1 and soil varied from 8 to 15 mg.kg^?1. The results point to the rocks as the primary sources of lead.     

Mercury contamination in the vicinity of a chlor-alkali plant and potential risks to local population

A mercury-cell chlor-alkali plant operated in Estarreja (North-western Portugal) for 50 years causing widespread environmental contamination. Although production by this process ceased in 2002, mercury contamination from the plant remains significant. The main objective of this study was to investigate mercury impact on the nearby environment and potential risks to local population. To assess the level of contamination soil samples were collected from agricultural fields in the vicinity of the plant, extending the study by taking samples of the predominant vegetation suitable for animal and human consumption, water samples, and fish species from a nearby coastal lagoon, to gain a preliminary insight into the potential for contamination of the terrestrial and aquatic food web. To determine population exposure to mercury, hair samples were collected from local residents. Total mercury concentration in the 0-15 cm layer of soil was found to be highly variable, ranging between 0.010 and 91 mg kg^− 1, although mercury contamination of soils was found to be restricted to a confined area. Lolium perenne roots contained between 0.0070 and 2.0 mg kg^− 1, and there is evidence that root systems uptake mercury from the soil. Levels of mercury in the aerial parts of plants ranged between 0.018 and 0.98 mg kg^− 1. It appears that plants with higher mercury concentration in soils and roots also display higher mercury concentration in leaves.Total mercury concentration in water samples ranged between 12 and 846 ng L^− 1, all samples presenting concentrations below the maximum level allowable for drinking water defined in the Portuguese law (1.0 μg L^− 1).Mercury levels in fish samples were below the maximum limit defined in the Portuguese law (0.5 mg kg^− 1), ranging from 0.0040 to 0.24 mg kg^− 1. Vegetables collected presented maximum mercury concentration of 0.17 mg kg^− 1. In general, food is not contaminated and should not be responsible for major human exposure to the metal.Mercury determined in human hair samples (0.090-4.2 mg kg^− 1; mean 1.5 mg kg^− 1) can be considered within normal limits, according to WHO guidelines suggesting that it is not affecting the local population. Despite being subject to decades of mercury emissions, nowadays this pollutant is only found in limited small areas and must not constitute a risk for human health, should these areas be restricted and monitored.Considering the present data, it appears that the population from Estarreja is currently not being affected by mercury levels that still remain in the environment.     

Concentrations and risks of polycyclic aromatic hydrocarbons in smoke-cured fish products in Nigeria

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in nine popular smoked fish species, (Clarias gariepinus, Parachana obscura, Heterotis niloticus, Pseudotolithus senegalensis, Gymnarchus niloticus, Ethmalosa fimbriata, Sardinella aurita, Scromber scrombus and Trachurus trachurus), in the Nigerian market by using gas chromatography-mass spectrometry after extraction by ultrasonication with hexane/dichloromethane. The mean concentrations of ∑16 PAHs in these species ranged from 52.4 μg kg^?1 to 1230 μg kg^?1. The estimated margins of exposure (MOE values) were less than 10,000 for C. gariepinus, G. niloticus and E. fimbriata indicating serious concern for the consumers’ health. The estimated excess cancer risk factors for these fish species investigated indicate that approximately 1 to 65 out of 10⁶ equally exposed adults may suffer from cancer and cancer-related diseases during their lifetime through the ingestion of carcinogenic PAHs from smoked fish in their diet.     

Exposure of man to environmental arsenic — an exposure commitment assessment

The Monitoring and Assessment Research Centre (MARC) has been developing and applying the exposure commitment method to the assessment of pollutant transport in the regional and global environment. Exposure commitments give a basis for comparing contributions to exposure from various pathways and for estimating equilibrium concentrations resulting from continuing releases. As an illustration of the method, environmental aspects of arsenic are summarised and relationships are formulated between environmental sources and concentrations of arsenic in the body.Arsenic is present in the environment primarily in inorganic form; however, relatively higher concentrations of arsenic in organic forms occur in fish. Ingestion intake by man is variable, dependent on seafood consumption and also on geography, determining for example the levels which may be present in drinking water. Based on measured absorption and retention of arsenic in man, it is estimated that an ingestion intake rate of arsenic in terrestrial foods of 1 mg y^?1 contributes a concentration of arsenic in the body of 0.28 μg kg^?1. The relationship is 0.14 μg kg^?1 per mg y^?1 intake of organic arsenic in seafood. The body burden of arsenic is estimated to be about 1 mg from reported tissue measurements and from representative intake estimates. Harmful effects from arsenic in the body could be expected at levels perhaps 5 to 80 times the current background levels. Uncertainties are recognized. Improved estimates of the transfer fractions can be made as additional data are acquired.     

Mn and Ni contents in soils of a qualified denomination of origin region: Rioja D.O.Ca,Spain

The distribution of Mn and Ni in soils of one of the most famous winegrowing regions of Spain, Rioja D.O.Ca (Denomination of origin, Spain's top category), was studied in detail according to its geographical location. There were background concentrations of 288.81 mg kg^?1 total Mn in the surface horizon and 296.06 mg kg^?1 in the subsoil; and a total Ni content of 17.89 mg kg^?1 in the surface horizon and 24.76 mg kg^?1 in the subsoil. The amounts of Mn bio- or phytoavailable were 5.28 mg kg^?1 in the upper horizon and 4.70 mg kg^?1 in the subsurface horizon; and for Ni bio- or phytoavailable, the amounts were 0.14 mg kg^?1 in the upper horizon and 0.13 mg kg^?1 in the deeper horizon. Spatial distribution patterns were established using GIS contour maps for the two elements, showing significant variations within and between the sites. The local contamination is generally associated with the quantities that are added to the soil or water from man-made sources such as industrial discharge and volatile emissions, sewage sludge, livestock wastes and other wastes.     

Mercury concentrations in fish inhabiting two polluted lakes in Northern Canada

The concentrations of total mercury in the sediments, water and fish of Giauque Lake and Thompson Lake in northern Canada were determined during 1977 and 1978. Both lakes had formerly received mercury-laden industrial discharges, which were terminated in 1968 (Giauque Lake) and 1949 (Thompson Lake). In Giaque Lake, lake trout (Salvelinus namaycusy) contained an average of 3.79 mg kg⁻¹ in their muscle while the average concentrations in northern pike (Esox lucius) and round whitefish (Prosopium cylindraceum) were 1.75 and 1.22 mg kg⁻¹ respectively. About 7% of the lake's bottom contained mercury levels of > 500 μg kg⁻¹ (dry weight) but, in the water, concentrations were always below detectable limits (0.2 μg l⁻¹). In Thompson Lake, mercury levels in northern pike averaged 1.69 mg kg⁻¹, whereas in lake whitefish (Coregonus clupeaformis), the highest recorded value was 0.6 mg kg⁻¹. Although mercury was usually not detectable in the water column, there was heavy contamination of the sediments, with values reaching 1300 μg kg⁻¹. In addition, approximately 15% of the lake bottom contained mercury in excess of 500 μg kg⁻¹. Based on these data, it is concluded that: (1) northern pike are still accumulating mercury from exposed tailings which were deposited in Thompson Lake 30 years ago, and (2) contamination of only a small part of a lake may result in high levels in fish throughout the lake: this is probably due to the movement of fish from contaminated to noncontaminated areas.     

Radioactivity of anthropogenic origin in the Tejo Estuary and need for improved waste management and environmental monitoring

The Tejo Estuary is a large water body surrounded by seven municipalities and industries with liquid effluent discharges containing contaminants that reach the estuary. This is the case for man-made radionuclides used in nuclear medicine, present in liquid effluents discharged by medical facilities. Radionuclide measurements in seaweeds, mussels, fish, water and sediments sampled along the North bank of the estuary revealed the presence of ¹³¹I and ^99mTc, originating from nuclear medicine facilities in Lisboa. Concentrations reached 90 Bq kg^?1 (wet weight) of ^99mTc in fish, and 18 Bq kg^?1 (wet weight) of ¹³¹I in mussels, and were even higher in the water. Another anthropogenic source of radionuclides is industrial waste, such as phosphogypsum the by-product of phosphoric acid production stockpiled at the South bank of the estuary. Main radionuclides present in phosphogypsum are ²²⁶Ra, ²¹⁰Pb, ²¹⁰Po and uranium. Concentrations of ²²⁶Ra in phosphogypsum are about 1000 Bq kg^?1, which is a high value in comparison with ²²⁶Ra in soils of the Tejo valley, <100 Bq kg^?1. ²²⁶Ra, in particular, is dissolved by rainwater from phosphogypsum stacks and seeps into the estuary. Other potential sources of radioactivity are discharges from naval nuclear powered vessels and merchant ships transporting radioactive materials that berth in the Lisboa harbour. A whole survey of the estuary indicated low concentrations of ¹³⁷Cs in sediments, mostly attributed to radioactive fallout. Since waste discharges are undergoing deep modifications due to enhanced urban waste treatment, but economic activities have changed and the use of radiopharmaceuticals increases, the periodic radioactivity monitoring of the Tejo Estuary is advised and should provide feedback to enhanced waste management.     

Assessment of chromium biostabilization in contaminated soils using standard leaching and sequential extraction techniques

The iron reducing microorganism Desulfuromonas palmitatis was evaluated as potential biostabilization agent for the remediation of chromate contaminated soils. D. palmitatis were used for the treatment of soil samples artificially contaminated with Cr(VI) at two levels, i.e. 200 and 500 mg kg^− 1. The efficiency of the treatment was evaluated by applying several standard extraction techniques on the soil samples before and after treatment, such as the EN12457 standard leaching test, the US EPA 3060A alkaline digestion method and the BCR sequential extraction procedure. The water soluble chromium as evaluated with the EN leaching test, was found to decrease after the biostabilization treatment from 13 to less than 0.5 mg kg^− 1 and from 120 to 5.6 mg kg^− 1 for the soil samples contaminated with 200 and 500 mg Cr(VI) per kg soil respectively. The BCR sequential extraction scheme, although not providing accurate estimates about the initial chromium speciation in contaminated soils, proved to be a useful tool for monitoring the relative changes in element partitioning, as a consequence of the stabilization treatment. After bioreduction, the percentage of chromium retained in the two least soluble BCR fractions, i.e. the “oxidizable” and “residual” fractions, increased from 54 and 73% to more than 96% in both soils.     

Assessment of heavy metals contamination and its effects on oyster (Saccostrea cucullata) biometry parameters in the Asaluyeh port coasts,Persian Gulf,Iran

The current study examines biometric parameters and concentration of some heavy metals in soft tissues of Saccostrea cucullata in the Asaluyeh coast, Persian Gulf, Iran. The metals concentration in the soft tissue of the Saccostrea cucullata ranged as: Zn: 765–3411 mg kg^?1, Cu: 120.3–580.6 mg kg^?1, Cd: 0.13–3.5 mg kg^?1, As: 0.39–3.3 mg kg^?1, Pb: 0.05–1.64 mg kg^?1, Ni: 0.02–0.44 mg kg^?1, V: 0.06–0.32 mg kg^?1, Cr: 0.02–0.16 mg kg^?1 and Hg: 0.002–0.068 mg kg^?1. The results showed that the concentration of total heavy metals in oysters of the control station (CA) is usually lower. The results also indicated lack of correlation between oyster biometric parameters and bioaccumulated heavy metals, except between Cu and longitudinal diameter (R = 0.77). The concentration of heavy metals is higher than limits recommended by the World Health Organization, except for Cd and Pb.     

Comparison of the Combustion of Pine Species with Two Sizes of Calorimeter: 10 g vs. 100 g

This study aims to analyze the scale effects on the combustion dynamics and smoke emitted during the burning of vegetation species under laboratory conditions. Experiments were carried out at two scales of combustion with two fuels (Pinus pinaster and Pinus laricio needles). Two oxygen consumption calorimetry devices were used: the cone calorimeter with samples in the scale of 10 g, and Large Scale Heat Release rate calorimeter (LSHR) with samples in the scale of 100 g. Fuel loads of 1.2 kg m^?2 and 1.04 kg m^?2 were considered respectively for Pinus pinaster and Pinus laricio needles. The parameters investigated to analyze the combustion dynamics are the heat release rate, combustion efficiency and mass loss rate. Measuring the extinction coefficient allowed us to obtain the soot emission factor. The emission factors of the combustion gases were obtained by using FTIR and NDIR detectors. A carbon mass balance showed that more than 95% of carbon was recovered. This study revealed an effect of scale on the combustion dynamics (peak HRR of 806 kW m^?2 and 651 kW m^?2 respectively at the bench scale and at full scale for Pinus pinaster), total smoke production, soot emission factor (1.32 g kg^?1 and 5.17 g kg^?1 respectively at the bench scale and at full scale for Pinus pinaster) and nitrogen compounds emission factors (2.47 g kg^?1 and 5.25 g kg^?1 for the NO respectively with the cone calorimeter and LSHR for Pinus laricio). Combustion efficiency appeared to be largely independent of the combustion scale (96.89% and 96.61% respectively at the bench scale and at full scale for Pinus pinaster). We also observed differences in the fire behavior for both types of needles.     

Selenium concentrations of common weeds and agricultural crops grown in the seleniferous soils of northwestern India

The plants grown in seleniferous soils constitute a major source of toxic selenium levels in the food chain of animals and human beings. Greenhouse and field experiments were conducted to study selenium concentrations of weeds, forages and cereals grown on seleniferous soils located between 31.0417° to 31.2175° N and 76.1363° to 76.4147° E in northwestern India. Eleven winter season (November-April) weed plants were grown in the greenhouse in a soil treated with different levels of selenate-Se. Selenium concentrations of weed plants increased progressively with the levels of selenate-Se in soil. The highest Se concentration was recorded by Silene gallica (246 mg kg^− 1) and the lowest by Avena ludoviciana (47 mg kg^− 1) at 2.5 mg Se kg^− 1 soil. A.ludoviciana and Spergula arvensis proved highly tolerant to the presence of 1.25 and 2.5 mg selenate-Se kg^− 1 soil and the remaining weeds were sensitive to Se. Dry matter yield of Se-sensitive weed plants was 25 to 62% of the yield in the no-Se control at 1.25 mg selenate-Se kg^− 1 and 6 to 40% at 2.5 mg selenate-Se kg^− 1 soil. Other symptoms like change in leaf colour and size, burning of leaf tips and margins, and delayed flowering were also observed due to Se. Dry matter yield of Se-sensitive weed plants expressed as percentage of yield in the no-Se control at both the Se levels was inversely correlated with their Se content (r = − 0.731, p < 0.01, N = 17). Among the weed plants grown in seleniferous soils under field situations, Mentha longifolia accumulated the highest Se (365 mg kg^− 1) and Phalaris minor the lowest (34 mg kg^− 1). Among agricultural crops grown on a naturally contaminated soil in the greenhouse, Se concentrations were the highest for oilseed crops (19-29 mg kg^− 1), followed by legumes (6-13 mg kg^− 1) and cereals (2-18 mg kg^− 1). Helianthus annuus among the oilseed crops, A.ludoviciana among the winter season weeds, M.longifolia among the summer season (May-October) weeds and Cirsium arvense among the perennial weeds can be used for phytoremediation of seleniferous soils as these accumulate the highest amounts of Se.     

Variation de la plombemie en fonction de la contamination par le plomb de l'eau livree a la consommation: Variation of the blood lead level as a result of lead contamination of the subjects drinking water

The combination of the chemical aggressivity of water and lead piping, as is well known, can cause severe cases of lead poisoning in those who consume such water. After a great number of observations and epidemiological studies which have strongly incriminated this metal in a wide range of pathologic conditions, other materials have been gradually substituted for lead; however, the problem remains.In compliance with a European Directive to survey the risk of lead poisoning (Council Directive, 1977), a random sample of 321 residents was selected from the Vosgian Mountains of France. This region is noted for its high incidence of cases of lead poisoning: 150 reported during 8 months in 1983 (Barbier et al., 1983).During the course of a health evaluation, a blood sample was taken from each subject for lead analysis. At the same time, a sample of tap-water (after running for 5 s) was taken from each subject home. Both lead analyses (blood and water) were performed by electrothermal atomization-atomic absorption spectrophotometry. Because of the log-normality of the distributions of the blood lead levels and the concentrations of lead in the drinking water, a logarithmic transformation was performed so that the results are expressed as the geometric mean, which for the amount of lead in the drinking water of our sample was found to be 0.16 mg l^?1.Among the subjects of this study, 28% are served by water containing more than 0.10 mg l^?1 of lead (the standard for France) and 48% by water containing more than 0.05 mg l^?1 (the European and WHO standard). In concurrence with numerous authors, our study indicates that, among our subjects, the blood lead level is much higher in men than in women (geometric means 22.9 and 15.0 μg dl^?1 respectively); this difference is highly significant (t-test:P < 0.001). Table 1 summarizes the results, by sex, obtained in this region compared with those from a study (Huel, 1982) concerning an urban French population whose geometric mean blood lead levels were 15.9 μg dl^?1 for men and 11.4 μg dl^?1 for women. The irrespective of sex, is highly significant (P < 0.001). Table 2 shows the significance of the relation between these subjects, high blood lead levels and the concentration of lead in their drinking water, while Fig. 1 shows that for contamination levels up to 0.02 mg l^?1 of lead in water, the blood lead level remains relatively stable, while above this apparent “threshold” value, the blood lead level begins to increase finally reaching quite high values in response to high contamination levels, suggesting a direct translation of increases in the water above the 0.02 mg l^?1 level to increases in the blood.     

Inhibition of nitrification in the packed bed reactors by selected organic compounds

The effect of methanol, acetone, formalin and glucose on the nitrification process in the packed bed reactors has been investigated. For the utilized compounds the inhibition constant K_i was determined according to Dixon's method. The determined values were as follows: methanol K_i = 116.0 mg l^?1; acetone K_i = 804.2 mg l^?1; formalin K_i = 61.5 mg l^?1. The value of K_i for glucose has not been determined because glucose in applied concentration up to 11,325 mg l^?1 had no effect on the nitrification course.     

Enhanced removal of polychlorinated biphenyls from alfalfa rhizosphere soil in a field study: The impact of a rhizobial inoculum

Polychlorinated biphenyls (PCB) are persistent pollutants in soil environments where they continue to present considerable human health risks. Successful strategies to remediate contaminated soils are needed that are effective and of low cost. Bioremediation approaches that include the use of plants and microbial communities to promote degradation of PCB have significant potential but need further assessment under field conditions. The effects of growth of alfalfa (Medicago sativa L.) and inoculation with a symbiotic nitrogen fixing bacterium (Rhizobium meliloti) on the removal of polychlorinated biphenyls (PCB) from rhizosphere soil were evaluated in a field experiment. The initial PCB content of the soil ranged from 414 to 498 µg kg⁻¹. PCB removal for the rhizosphere soil was enhanced in the planted treatments, an average of 36% decrease in PCB levels compared to a 5.4% decrease in the unplanted soil, and further enhanced when plants were inoculated with the symbiotic Rhizobium (an average of 43% decrease) when evaluated at 90 days after planting. Plant biomass production was higher in the inoculated treatment. The total PCB content was increased from 3.30 µg kg⁻¹ to 26.72 µg kg⁻¹ in plant shoots, and from 115.07 µg kg⁻¹ to 142.23 µg kg⁻¹ in roots in the inoculated treatment compared to the planted treatment. Increased colony forming units (cfu) of total heterotrophic bacteria, biphenyl-degrading bacteria and fungi were observed in the rhizosphere of inoculated plants. PCB removal from the rhizosphere soil was not significantly correlated with the direct PCB uptake by the plants in any of the treatments but was significantly correlated with the stimulation of rhizosphere microflora. Changes in the soil microbial community structure in the planted and inoculated treatment were observed by profiling of bacterial ribosomal sequences. Some bacteria, such as Flavobacterium sp., may have contributed to the effective degradation of PCB and deserve further investigation.     

In-vivo estimates for the uptake of caesium-137 by cattle grazing contaminated pasture around the Esk and Irt estuaries,Cumbria, U.K.

Sea water contaminated with diluted radioactive effluent from the Windscale nuclear complex in Cumbria periodically floods low-lying grazing pasture around the estuaries of the rivers Esk, Irt and Mite near Ravenglass. During 1979, an experiment was carried out to measure the transfer of caesium-137 from grass to muscle in cows grazing these pastures. Grass samples were taken and in vivo external gamma-ray measurements were made on cattle. A very low transfer coefficient was found, less than 9 × 10^?4 days kg^?1 with a best estimate of 4 × 10^?4 days kg^?1, compared with a more usual value of around 3 × 10^?2 days kg^?1. The low transfer seems to occur because the bulk of the caesium-137 on the grass is bound to resuspended estuarine surface sediment deposited during flooding. In this form, the caesium-137 is only poorly absorbed across the gut of the grazing cattle.