The entrainment of nutrients from below the thermocline in the coral sea into the great barrier reef lagoon via cook's passage

Cool, nitrate-enriched water is drawn into Cook's Passage by rapid inflowing tidal currents. The water is a mixture of surface Coral Sea water and subtropical lower water. At depths > 30 m, the range of the mean nitrate concentration for outflows, calculated from hourly measurements, was 0.25–0.8 μg 1⁻¹, and for inflows it was 1.0–1.5 μg 1⁻¹. The maximum values normally recorded were in the range 2.0–2.7 μg1⁻¹. The quantity of nitrate in the water column is not dependent solely on the tidal amplitude; undulations in the thermocline are believed to play a major role in determining how much enrichment takes place. In the 40 m water column examined, the nitrate concentration in outflowing waters appeared to be a function of the amount entrained on the previous incoming cycle, with a loss to the lagoon of approximately 16 mg under 1 m² of surface. The mean silicate concentrations in outflows and inflows were 32.0 ± 6.0 and 35.2 ± 4.6 μg 1⁻¹, respectively, with corresponding phosphate values of 4.5 ± 0.7 and 4.6 ± 0.9 μg 1⁻¹, respectively. Neither shows any distinctive relationship with tides.     

An environmental record of changes in sedimentary organic matter from Lake Sattal in Kumaun Himalayas, India

Sattal a small mountainous lake in the Kumaun Himalayas has been impacted by various cultural activities in recent years. We explored the effects of human-induced changes in this lake by using various geochemical proxies. Shifts in TOC and N flux, C/N ratio, stable isotopes (δ¹³C and δ¹⁵N), n-alkane, and pigment concentrations in sediments indicate a steady increase in primary productivity over the last few decades. The trophic status of the lake has changed from mesotrophic to eutrophic condition. The C/N, CPI, and TAR based ratios in sediments indicate accumulation of algal matter derived primarily from in situ production, with limited input of terrestrial organic matter from the watershed. The low (between 0.1 and 1‰) δ¹⁵N values imply N₂-fixation by cyanobacteria, and the decrease in δ¹³C values up-core represent the effect of sewage input and land based runoff, or possible contribution from microbial biomass. The pigments change from non-N₂ fixing cyanobacterial species to the N₂-fixing community, and are consistent with the proxy-based productivity shifts inferred in the lake. The deeper sediments are affected by post-diagenetic changes causing an increase in δ¹³C (and possibly δ¹⁵N) due to mineralization of organic C and N.     

Lead in coastal sediments: The case of the elefsis gulf,Greece

Lead was determined in surface sediments and cores of a typical, polluted, almost enclosed Mediterranean embayment, the Gulf of Elefsis, near Athens. Total lead concentrations of 500–600 μg g⁻¹ were found in the surface sediments of the northeast section of the gulf, near major industries. However, a few kilometers from the source the concentrations decrease to ∼ 40m μg g⁻¹; the background pre-industrial levels are ∼ 10 μg g⁻¹ (in the < 61 μm fraction). Sequential extractions, consideration of the Pb/Al and Pb/Zn ratios, etc., indicate that the upper 5–15 cm of the sediment column are greatly enriched with lead of anthropogenic origin, which is mainly associated with fine particles. Redox reactions play an important role in the distribution and chemistry of lead, most of which (∼ 40%) is associated with organic matter and sulphides (extracted by EDTA); another ∼ 30% is associated with iron and manganese coatings and carbonates, with only a small but significant 3–4% of the total in a readily exchangeable form. The latter, under given conditions, may influence the lead concentrations in the overlying waters.     

Carbon cycling in a zero-discharge mariculture system

Interest in mariculture systems will rise in the near future due to the decreased ability of the ocean to supply the increasing demand for seafood. We present a trace study using stable carbon and nitrogen isotopes and chemical profiles of a zero-discharge mariculture system stocked with the gilthead seabream (Sparus aurata). Water quality maintenance in the system is based on two biofiltration steps. Firstly, an aerobic treatment step comprising a trickling filter in which ammonia is oxidized to nitrate. Secondly, an anaerobic step comprised of a digestion basin and a fluidized bed reactor where excess organic matter and nitrate are removed. Dissolved inorganic carbon and alkalinity values were higher in the anaerobic loop than in the aerobic loop, in agreement with the main biological processes taking place in the two treatment steps. The δ¹³C of the dissolved inorganic carbon (δ¹³C_DIC) was depleted in ¹³C in the anaerobic loop as compared to the aerobic loop by 2.5-3‰. This is in agreement with the higher dissolved inorganic carbon concentrations in the anaerobic loop and the low water retention time and the chemolithotrophic activity of the aerobic loop. The δ¹³C and δ¹⁵N of organic matter in the mariculture system indicated that fish fed solely on feed pellets. Compared to feed pellets and particulate organic matter, the sludge in the digestion basin was enriched in ¹⁵N while δ¹³C was not significantly different. This latter finding points to an intensive microbial degradation of the organic matter taking place in the anaerobic treatment step of the system.     

Trihalomethanes in the drinking water of Concepción and Talcahuano,Chile

Formation of trihalomethanes (THMs) during water disinfection has been related to several health problems, although the magnitude of these effects is under discussion. This paper quantifies the THMs in drinking water from the Bío‐Bío Region of central Chile, the first since the modification of the national reference value (Nch 409/05) to include maximal values for THMs. THMs were quantified using a solid phase micro‐extraction (SPME) method and GC‐MS. The concentration ranges were 9.7–111.6, 0.1–1.0 and 0.9–25.5 μg/L for chloroform (CHCl₃), and dibromochloromethane (CHClBr₂) and bromodichloromethane (CHCl₂Br), respectively. Bromoform was not detected in any sample. There were good correlations (R²=0.91–0.98, P<0.001) between the THMs and the residence time of the water, the distance from the treatment plant and an inverse correlation to free chlorine in the water. The Additive Toxicity Index Value (0.07–1.00) showed that all samples were within the Chilean reference value for THMs in drinking water. However, several values were close to exceeding the maximum permitted concentration (200, 100, 100 and 60 μg/L for CHCl₃, CHBr₃, CHClBr₂ and CHCl₂Br, respectively), which may occur when the water demand is low and thus residence times are longer.     

Characterization and grouping of aquatic fulvic acids isolated from clear-water rivers and lakes in Japan

Characteristics of aquatic fulvic acids (FAs) from 10 clear waters in Japan (around the temperate zone) were revealed by several analytical techniques—high performance size exclusion chromatography (HPSEC), elemental analysis, liquid-state ¹³C NMR spectroscopy, isotopic analyses (δ¹³C and δ¹⁵N), and compared with those of International Humic Substances Society (IHSS) standard samples including FAs from brown waters (Suwannee, Pony, and Nordic FAs). Generally clear-water FAs were different from brown-water FAs in chemical properties. Weight-average molecular weights (Mw) of the clear-water FAs were similar to each other, whereas their elemental compositions and carbon species distribution were different. The clear-water FAs all exhibited a high proportion of alkyl carbons, which may be attributed to microbial activity. δ¹³C and δ¹⁵N values of the FAs indicated that there would be a huge gap between origin and chemical structure of clear-water FA. Results of the chemical structural analyses described above were not always linked to those of the isotopic analyses (δ¹³C and δ¹⁵N). Multivariate statistical analysis, i.e. cluster and principal component analysis was applied to reveal differences or similarities in a more objective manner. The FAs were always classified into two clear-water groups and one brown-water group. Aryl-C and O-Alkyl-C contents were important for the grouping. We speculate that the grouping might depend on the differences of aquatic microbial activity caused by the differences of residence time of water.     

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.     

Blood lead levels in Finnish preschool children

The blood lead (PbB), hemoglobin and hematocrit were measured in 286 Finnish children living in the three largest cities of Finland (n = 172), in rural areas (n = 54) and in a lead smelter area (n = 60). PbB was determinated using an atomic absorption spectrophotometric micro method. The precision of the method was good, as was the accuracy tested by an international interlaboratory comparison. The mean PbB in urban, rural and lead smelter areas varied between 6.0–6.7 μg/100 ml⁷ (range 3–17 μg/100 ml) and there were no significant differences between the residential areas. The mean values of hemoglobin and hematocrit were in the normal range. The PbB values in Finnish children studied were low compared with many international studies but at a similar level as in some recent Scandinavian studies.     

The correlation of trihalomethanes with other disinfections by-products and fractionation of dissolved organic carbon in Dez River water

This work assesses the correlation between trihalomethanes (THM) and the formation potential (THMFP) of other disinfections by-products and the fractionation of natural organic matter in Dez River water in Iran. The THMFP of Dez River water was well correlated with the haloacetonitriles (R ² = 0.796) and haloacetic acids (R ² = 0.907) formation potential. The most abundant fraction of natural organic matter in the river was hydrophobic acid fraction (49.4 μg/L). The study demonstrated that however the THMFP of Dez River water was relatively high but a usual waterworks could effectively reduce THMFP.     

Stable isotopes of bulk organic matter to trace carbon and nitrogen dynamics in an estuarine ecosystem in Babitonga Bay (Santa Catarina, Brazil)

The biogeochemical processes affecting the transport and cycling of terrestrial organic carbon in coastal and transition areas are still not fully understood. One means of distinguishing between the sources of organic materials contributing to particulate organic matter (POM) in Babitonga Bay waters and sediments is by the direct measurement of δ¹³C of dissolved inorganic carbon (DIC) and δ¹³C and δ¹⁵N in the organic constituents. An isotopic survey was taken from samples collected in the Bay in late spring of 2004. The results indicate that the δ¹³C and δ¹⁵N compositions of OM varied from − 21.7‰ to − 26.2‰ and from + 9.2‰ to − 0.1‰, respectively. δ¹³C from DIC ranges from + 0.04‰ to − 12.7‰. The difference in the isotope compositions enables the determination of three distinct end-members: terrestrial, marine and urban. Moreover, the evaluation of source contribution to the particulate organic matter (POM) in the Bay, enables assessment of the anthropogenic impact. Comparing the depleted values of δ¹³C_DIC and δ¹³C_POC it is possible to further understand the carbon dynamic within Babitonga Bay.     

A semiautomated procedure for the determination of phosphorus in water, waste waters and particulates

Improved procedures for the determination of total dissolved phosphorus (TDP), particulate phosphorus (PP) and dissolved inorganic orthophosphate (DP) are described. Organic particulate material is solubilized in 5 n NaOH, and phosphorus compounds are oxidized and mineralized to orthophosphate by persulfate digestion. DP is determined by an improved automated molybdenum blue procedure that does not require sample pH adjustment or a correction for silicate interference in the 0–50 mg Si 1^?1 range. The use of 36-position digestion racks allows 32 TDP or PP samples to be digested in ca. 1 and 4 h respectively. Detection limits in μg of phosphorus 1^?1 are DP, 2; TDP, 5; and PP. 1. Waste water samples were analyzed for TDP and PP by the nitric acid-sulfuric acid procedure and by the proposed method. There was no significant difference between the two sets of data (P > 0.45).     

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.     

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.     

Pollution status of the Indus River,Pakistan, through heavy metal and macronutrient contents of fish,sediment and water

Concentrations of Ag, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Hg, together with Na, K, Ca and Mg in 19 species of fish captured from the Indus River, Pakistan, are estimated by the atomic absorption method. Corresponding data for sediment and water from 11 sites along the down-stream route of the river are also reported. Mercury and arsenic concentrations were high (3.920 and 3.072 μg/g, respectively) in the muscle of fish from Guddu barrage as compared with those from other sites. Hetroptirus fossilus showed maximum concentrations of Ag, Cu and Pb in its muscle as compared with other fish. Labeo calbasu from Guddu barrage showed highest As concentration at 3.072 μg/g. Mystus vitatus from Chashma barrage contained maximum cadmium concentration at 0.990 μg/g. Several other fish exhibited elevated levels of metals along the downstream route of the river, a trend exhibited also by the elevated metal contents of sediment and water at Guddu and Lloyd barrages. The study indicated a gross pollution of the sediment and water at various locations of the river, e.g. As (7.452 μg/g) in sediment from Lloyd barrage, Hg (5.710 μg/g) in sediment from Jinnah barrage, Pb (2.709 μg/g) in sediment from Guddu barrage and Mn (0.038 μg/g) in water from Lloyd barrage. The macronutrients showed an inverse relationship with trace metals. Hetroptirus fossilus could be used as indicator species for Ag, Cu and Pb.     

Biological iron oxidation by Gallionella spp. in drinking water production under fully aerated conditions

Iron oxidation under neutral conditions (pH 6.5-8) may be a homo- or heterogeneous chemically- or a biologically-mediated process. The chemical oxidation is supposed to outpace the biological process under slightly alkaline conditions (pH 7-8). The iron oxidation kinetics and growth of Gallionella spp. - obligatory chemolithotrophic iron oxidizers - were assessed in natural, organic carbon-containing water, in continuous lab-scale reactors and full-scale groundwater trickling filters in the Netherlands. From Gallionella cell numbers determined by qPCR, balances were made for all systems. The homogeneous chemical iron oxidation occurred in accordance with the literature, but was retarded by a low water temperature (13 °C). The contribution of the heterogeneous chemical oxidation was, despite the presence of freshly formed iron oxyhydroxides, much lower than in previous studies in ultrapure water. This could be caused by the adsorption of natural organic matter (NOM) on the iron oxide surfaces. In the oxygen-saturated natural water with a pH ranging from 6.5 to 7.7, Gallionella spp. grew uninhibited and biological iron oxidation was an important, and probably the dominant, process. Gallionella growth was not even inhibited in a full-scale filter after plate aeration. From this we conclude that Gallionella spp. can grow under neutral pH and fully aerated conditions when the chemical iron oxidation is retarded by low water temperature and inhibition of the autocatalytic iron oxidation.     

Arsenic in coastal waters of South Australia

Surface seawater samples from South Australian coastal locations were analysed for dissolved inorganic arsenic [As(III) + As(V)], arsenite [As(III)] and particulate arsenic.Dissolved inorganic arsenic concentrations ranged from 1.10 to 1.61 μg As l^?1 (average 1.3 ± 0.1 μg As l^?1) with 1.2–4.3% (average 2.7%) present as arsenite. Particulate arsenic concentrations were below the limit of detection (0.0006 μg As l^?1) at most sampling stations.     

Co-occurrence and potential chemical competition of phosphorus and silicon in lake sediment

Various chemical approaches were used to characterize P and Si in the surface sediment of Lake Vesijärvi, Southern Finland. The dynamic equilibrium between solid and solution P in aerobic and anaerobic sediment was investigated by means of desorption-sorption isotherms. The sediment material was rich in hydrated Al and Fe oxides and, accordingly, had a high P sorption capacity and a very low P concentration (5 μg l⁻¹) in the interstitial water under aerobic conditions. Approximately 25–30% of total P and almost 90% of total Si were bound in mineral lattices, i.e. in a stable form not participating in biological and chemical transformations. Organic P comprised about 20–25% of total P and was mainly in practically insoluble form not extractable by dilute base or acid. Phosphorus participating in sorption-desorption reactions was considered to originate from reserves bound on oxide surfaces. When the oxide bound P reserves were determined by fractionation analysis, a large amount of Si (corresponding to about 30% of biogenic reserves) was also dissolved. Anaerobiosis increased distinctly the occurrence of both elements in the interstitial water. These dissolution patterns suggest that P and Si are bound to the same components and, therefore, compete with each other for the sorption sites. This chemical competition, in turn, may be of importance in the nutrient exchange between solid and solution phase in sediment.     

Temporal flux and spatial dynamics of nutrients, fecal indicators, and zoonotic pathogens in anaerobic swine manure lagoon water

Confined animal feeding operations (CAFOs) often use anaerobic lagoons for manure treatment. In the USA, swine CAFO lagoon water is used for crop irrigation that is regulated by farm-specific nutrient management plans (NMPs). Implementation of stricter US environmental regulations in 2013 will set soil P limits; impacting land applications of manure and requiring revision of NMPs. Precise knowledge of lagoon water quality is needed for formulating NMPs, for understanding losses of N and C in ammonia and greenhouse gas emissions, and for understanding risks of environmental contamination by fecal bacteria, including zoonotic pathogens. In this study we determined year-round levels of nutrients and bacteria from swine CAFO lagoon water. Statistical analysis of data for pH, electrical conductivity (EC), inorganic and organic C, total N, water-soluble and total minerals (Ca, Cu, Fe, K, Mg, Mn, P, and Zn) and bacteria (Escherichia coli, enterococci, Clostridium perfringens, Campylobacter spp., Listeria spp., Salmonella spp., and staphylococci) showed that all differed significantly by dates of collection. During the irrigation season, levels of total N decreased by half and the N:P ratio changed from 9.7 to 2.8. Some seasonal differences were correlated with temperature. Total N and inorganic C increased below 19 °C, and decreased above 19 °C, consistent with summer increases in ammonia and greenhouse gas emissions. Water-soluble Cu, Fe, and Zn increased with higher summer temperatures while enterococci and zoonotic pathogens (Campylobacter, Listeria, and Salmonella) decreased. Although their populations changed seasonally, the zoonotic pathogens were present year-round. Increasing levels of E. coli were statistically correlated with increasing pH. Differences between depths were also found. Organic C, total nutrients (C, Ca, Cu, Fe, Mg, Mn, N, P, and Zn) and C. perfringens were higher in deeper samples, indicating stratification of these parameters. No statistical interactions were found between collection dates and depths.     

Studies on oxidation of benzo [a] pyrene by sunlight and ozone

The destruction of the carcinogen benzo[a]pyrene (BaP) by light is well known; laboratory workers are routinely advised to cover fluorescent lamps with yellow filters while treating samples containing BaP. However until recently the mechanism of oxidation by sunlight and ozone had not been studied in detail. Concentrations of benzo[a]pyrene in urban air are in the range of 5–10 μg/1000 m³. Oxidant concentrations (predominantly in the form of ozone) are reported to be in the range of 0.01 ppm (22 μg per m³). Thus a sampling system with a filter paper would filter about 22,000 μg of ozone passing through and collect about 5 μg of BaP for analysis. The effect of interactions of such large ozone concentrations with BaP deposited on the filter paper is reported; data for the oxidation rates for benzo[a]pyrene coated on quartz surface and exposed to ozone or sunlight are presented. The oxidation products were analysed by thin-layer chromatography and highpressure liquid chromatography. From about eight products detected in these experiments, three have been identified as quinones based on UV-absorption spectrometry and mass spectrometry. Oxidation rates as high as 100% per hour of exposure are observed when less than 0.1 μg of BaP is coated inside the quartz tubes and exposed to ozone or sunlight. Oxidation rates for benzo[a]pyrene (using tritiated BaP) were determined for two types of experimental conditions. In the first set, tritiated BaP was spotted onto a glass fibre paper and sampling continued for 24 h; the loss of BaP was found to be 88%. In the second set tritiated BaP was spotted at intervals of one hour, for eight hours, while sampling is being carried out and the loss of BaP during the period was estimated to be 50%.     

Influence of pH,salinity, and selenium on the growth of Aeromonas veronii in evaporation agricultural drainage water

Aeromonas veronii was isolated from seleniferous agricultural drainage water and characterized in terms of growth kinetics under changing environmental parameters [i.e. pH, selenium (Se) and salinity (electrical conductivity, EC)] that simulated evaporation. Aeromonas veronii metabolized peptone and was active in volatilizing Se, principally as dimethyl selenide (DMSe). Other volatile products produced included dimethyl disulfide, methyl selenol, dimethyl selenosulfide and dimethyl diselenide. The rate of Se volatilization correlated with the growth of A. veronii, with the highest levels of DMSe released during the exponential phase of growth. The C assimilated was primarily respired as CO₂ or incorporated into cell biomass with a small fraction used in the alkylation of Se. The maximum growth rate (μ_max) for A. veronii was 0.23 h⁻¹ at pH 7.94, 10 μg Se 1⁻¹, and EC of 3.9 dS m⁻¹ and decreased to 0.06 h⁻¹ with increasing salt content (40.2 dS m⁻¹), pH (8.53) and Se (500 μg l⁻¹). Salinity appeared to be the dominant inhibitory factor as observed by a decrease in growth rate and mass of cells. The range in salt content that was most inhibitory to the growth rate of A. veronii was from EC 11.7 to 40.2 dS m⁻¹. As drainage waters evaporate in holding facilities, salinity tends to increase having serious ecological effects on the growth of A. veronii.