Histological and toxicological responses of the mummichog, Fundulus Heteroclitus (L.) to combinations of levels of cadmium and dissolved oxygen in a freshwater

Impact of dissolved oxygen concentration (D.O.) on toxicity of cadmium to mummichogs in a freshwater medium and histological changes associated with exposure were determined. Levels of mortality were related to duration of exposure, cadmium concentration, and levels of dissolved oxygen. Median tolerance concentrations, at 96h, ranged upward from 1.3 to about 3.0 mg Cd 1⁻¹ at 2.3 and 8.5 mg DO 1⁻¹, respectively. Statistical analyses of mortality data showed factors examined were interdependent and that Cd × DO and Cd × time interactions were significant (P < 0.01). No histopathology was evident at 3 mg Cd 1⁻¹, although histopathology was evident in gills from fish exposed to 28 mg Cd 1⁻¹ for 6 1/2 h.

Responses of mummichogs to cadmium in freshwater are compared with results of a previous study involving exposure of the species to cadmium in seawater and with responses of freshwater fishes subjected to various heavy metals. Differences and similarities in patterns of response are discussed in terms of water balance.     

The impact of combined sewer overflows on the dissolved oxygen concentration of a river

As described in the preceding paper by Harremoës (Harremoës, Water Res.16, 1093–1098, 1982) it is important to distinguish between removal and degradation of organic matter for non-steady-state discharges to rivers. These effects were investigated to determine the impact of combined sewer overflows on the dissolved oxygen concentration of a small river. Two different effects on the DO-concentration in the receiving river were observed during and after the passage of the bulk of combined sewage discharged at an existing outlet:

1. 1. An immediate effect caused mainly by degradation of the soluble BOD-fraction in the water body and by direct absorption and degradation of organic matter at the bottom.

2. 2. A delayed effect caused by degradation of adsorbed soluble, colloidal and fine particulate organic matter. After the passage of the bulk discharge a delayed effect on the DO-concentration in the river would be observed. This delayed effect lasted 12–24 hours after the discharge event.

Only 4% of the discharged organic matter was degraded during passage of the investigated stretch of the river, approx. 4 km. On the other hand about 35% of the discharged organic matter was removed by transfer to the bottom sediments. The rest was carried past the stretch of river investigated. This results in a rate of adsorption from the water phase of k = 9 m day⁻¹. The deposited organic matter was degraded with a first order reaction rate of K₄ = 0.75 day⁻¹.     

The interaction of treated bleached kraft mill effluent and dissolved oxygen concentration on the survival of the developmental stages of the sheepshead minnow (Cyprinodon variegatus)

The interactions of treated bleached kraft mill effluent (BKME) and dissolved oxygen concentration (DO) on the survival of the embryo, fry, juvenile and adult stages of the sheepshead minnow, Cyprinodon variegatus, were studied under continuous-flow 96 h bioassay conditions. Embryo survival was dependent on effluent concentration only and showed no interaction at nominal DO concentrations of 1.0, 3.0 and 5.0 mg l⁻¹. Survival of the fry was related solely to DO concentration with no interaction with BKME concentrations up to 100%. Juvenile sheepshead minnows showed increased sensitivity to BKME at a nominal DO concentration of 1.0 mg l⁻¹. Adult fish were not affected by BKME at any of the DO concentrations tested. This study shows that the acute toxicity of BKME effluent to sheepshead minnows is a function of the developmental stage of the organism and DO concentration in the receiving stream.     

The acute toxicity of dissolved elemental phosphorus to cod (Gadus morhua)

The acute toxicity of dissolved elemental phosphorus to cod (Gadus morhua) has been investigated in the absence of colloidal phosphorus. The 48 h lc₅₀ for dissolved elemental phosphorus is 14·4 μg l⁻¹, and evidence is presented that the incipient lethal level is ca. 1–2 μg l⁻¹. Elemental phosphorus was rapidly assimilated into the body tissues of the test animals. The distribution of phosphorus was homogeneous in the muscle tissue with levels ca. 10–30 times the exposure level, highest concentrations were measured in the liver.Preliminary data are reported which indicate that the biological half life of accumulated elemental phosphorus is very short when exposure is ended.     

The effects of tropospheric ozone and elevated carbon dioxide on potato (Solanum tuberosum L. cv. Bintje) growth and yield

An open-top chamber experiment with field grown potato (Solanum tuberosum L. cv. Bintje) was performed in the south-west of Sweden in 1998. The experiment was aimed to investigate individual and interactive impacts of elevated ozone (O₃) and carbon dioxide (CO₂) on potato growth and yield. Treatments were ambient and elevated CO₂ with or without the addition of 20 nmol mol⁻¹ O₃. In addition, plants were grown in ambient air plots. Plants grown in elevated CO₂ and O₃ had a reduced tuber yield, compared to control, by 2% and 8%, respectively. These effects were, however, not statistically significant. Elevated CO₂ caused a significantly larger number of tubers of lower average size, while elevated O₃ induced significantly lower tuber dry matter content. The number of tuber initials (tubers <15 mm) found at harvest was significantly lower in elevated O₃. Visible O₃ leaf injury appeared earlier and the number of yellow leaves 89 days after emergence was significantly larger in elevated O₃. In elevated CO₂, haulm dry weight was significantly (15%) lower at harvest and the haulm/tuber ratio was significantly reduced. There were significant interactive effects of O₃ and CO₂ on the final number of leaves and on stem height. Plants in elevated CO₂ reached final stem height earlier than in the other treatments. In summary, it was concluded: (a) that anticipated future O₃ levels are likely to have a negative impact on potato growth, although tuber yield effects may be hard to demonstrate experimentally in this plant due to large variation; (b) that whether any possible beneficial effect of elevated CO₂ on the magnitude of tuber yield will be expressed, depend on the climatic conditions prevailing; and (c) that potato growth responses to CO₂ and O₃ are not simply additive.     

Exchange of oxygen and carbon dioxide across the water surface during algal blooms in a pond

Exchange of O₂ and CO₂ across the water surface during algal blooms was studied in an experimental pond from measurements of O₂ and TCO₂, pH and chlorophyll-a. Production and consumption rates of O₂ due to biological activity were also measured using light and dark bottles.Algal blooms occurred twice during the experimental period of 22 days. The trajectory on the phase plane showing the time changes in concentration of O₂ and TCO₂ made a clockwise, converging loop. A new concept and quantity called total oxygen (TO₂), which is the sum of the concentrations of O₂ and TCO₂, is proposed in order to distinguish the role of gas exchange from that of deposits. From the analysis of the trajectory, the total amount of TO₂ was found to decrease during the production period, and increase during the decomposition period. This was due to the difference between O₂ and TCO₂. The mass transfer coefficient of O₂ was found to be (3.6 ± 1.9) × 10⁻⁴, and that of TCO₂ (1.0 ± 0.5) × 10⁻⁴ cm s⁻¹.During the production period, 60% of produced O₂ was lost to the atmosphere, and 20% of consumed TCO₂ was supplied from the atmosphere. During the decomposition period, 80% of consumed O₂ was supplied, and 35% of produced TCO₂ was lost.     

Morphological changes in the gill of carp (Cyprinus carpio L.) exposed to acutely toxic concentrations of methyl bromide

The acute toxicity of methyl bromide (CH₃Br) to carp (Cyprinus carpio L.) was determined in experiments with a 4 h exposure period. The 4 h-LC₅₀ was calculated at approx. 17 mg 1⁻¹, i.e. the order of magnitude of actually encountered peak concentrations in surface water. The concentration-effect curve was found to be very steep and the response was somewhat delayed. Morphological damage to the gill epithelium, indicative of alkylation of cell membranes, was the most pronounced effect of CH₃Br. It consisted of initial swelling of the lymphatic space and vacuolization of the epithelial cells, followed by disintegration of the epithelium and invasion of leucocytes. Death of the fish was probably caused by suffocation.     

Experimental investigation of the air flow and indoor carbon dioxide concentration in classrooms with intermittent natural ventilation

Air flow and the associated indoor carbon dioxide concentrations have been extensively monitored in 62 classrooms of 27 naturally ventilated schools in Athens, Greece. The specific ventilation patterns as well as the associated carbon dioxide concentrations, before, during and after the teaching period are analysed in detail. During the teaching period, only 23% of the measured classrooms presented a flow rate higher than the recommended value of 8 l/p/s while the mean daily fluctuation was close to 40%. About, 52% of the classrooms presented a mean indoor CO₂ concentration higher than 1000 ppm. The specific experimental data have been compared against existing ventilation rates and carbon dioxide concentrations using published information from 287 classrooms of 182 naturally ventilated schools and 900 classrooms from 220 mechanically ventilated schools. The relation between the air flow rates and the corresponding indoor carbon dioxide is analysed and then compared to the existing data from naturally and mechanically ventilated schools. It is found that all three data sets present a CO₂ concentration equal to 1000 ppm for air flows around 8 l/p/s. Specific adaptive actions to improve the indoor environmental quality have been recorded and the impact of indoor and ambient temperatures as well as of the carbon dioxide concentration on window opening is analysed in detail. A clear relation is found, between the indoor temperature at which the adapting action takes place and the resulting air flow rate. In parallel, a statistically significant relation between window opening and the indoor–outdoor temperature difference has been established.     

The influence of ammonia and carbon dioxide on the sorption of a basic organic pollutant to a mineral surface

Indoor surfaces have a sorptive capacity for organic pollutants which may be significantly influenced by other gases and the pH of the surface. In this research, we examine the influence of a common indoor gaseous acid, CO2, and base, NH3, on the adsorption of a volatile organic base, trimethylamine (TMA), to a mineral surface, zirconium silicate beads. Varying ammonia and CO2 within concentration ranges of indoor relevance substantially influences the sorptive capacity of this mineral surface. Increasing the CO2 mixing ratio to 1000 p.p.m. enhances surface capacity of TMA by 40-50%; increasing the NH3 mixing ratio to 10 p.p.m. decreases the TMA surface capacity by approximately 5-80% depending on relative humidity. The phenomena of dissolution of TMA into bulk surface water and acid-base chemistry in the surface water do not adequately describe equilibrium adsorption on this surface. Instead, adsorption to the dry solid or to adsorbed water layers appears to dominate. Reduction in the equilibrium partition coefficient, ke, in the presence of NH3 is due to a competition between TMA and ammonia molecules for adsorption sites. Site competition appears to follow the Langmuir competitive model and most ke values range from 0.003-0.045 m. PRACTICAL IMPLICATIONS: Sorptive interactions with indoor surfaces strongly influence indoor exposure to pollutants. For basic or acidic compounds, these interactions are themselves influenced by surface pH and competition with other acidic or basic gases such as CO2 and NH3. We show that CO2 tends to cause mineral surfaces to store more amines but NH3 tends to decrease this surface capacity. Given the typical range of indoor CO2 and NH3 concentrations, the indoor sorbtive capacity of amines on mineral surfaces may vary by greater than an order of magnitude.     

Biodegradability determinations via unspecific analyses (chemical oxygen demand, dissolved organic carbon) in coupled units of the oecd confirmatory test—I. The test

A method was developed which allows the determination of COD and/or DOC elimination rates of organic materials in the OECD Confirmatory Test, i.e., under realistic sewage treatment conditions at interesting and realistic test concentrations. A statistical justification for the test is provided.     

Gully hotspot contribution to landscape methane (CH4) and carbon dioxide (CO2) fluxes in a northern peatland

Peatlands are long term carbon catchments that sink atmospheric carbon dioxide (CO(2)) and source methane (CH(4)). In the uplands of the United Kingdom ombrotrophic blanket peatlands commonly exist within Calluna vulgaris (L.) dominated moorland ecosystems. These landscapes contain a range of topographical features that influence local hydrology, climate and plant community composition. In this study we examined the variation in ecosystem CO(2) respiration and net CH(4) fluxes from typical plant-soil systems in dendritic drainage gullies and adjacent blanket peat during the growing season. Typically, Eriophorum spp., Sphagnum spp. and mixed grasses occupied gullies while C. vulgaris dominated in adjacent blanket peat. Gross CO(2) respiration was highest in the areas of Eriophorum spp. (650+/-140 mg CO(2) m(-2) h(-1)) compared to those with Sphagnum spp. (338+/-49 mg CO(2) m(-2) h(-1)), mixed grasses (342+/-91 mg CO(2) m(-2) h(-1)) and C. vulgaris (174+/-63 mg CO(2) m(-2) h(-1)). Measurements of the net CH(4) flux showed higher fluxes from the Eriophorum spp (2.2+/-0.6 mg CH(4) m(-2) h(-1)) locations compared to the Sphagnum spp. (0.6+/-0.4 mg CH(4) m(-2) h(-1)), mixed grasses (0.1+/-0.1 mg CH(4) m(-2) h(-1)) and a negligible flux detected from C. vulgaris (0.0+/-0.0 mg CH(4) m(-2) h(-1)) locations. A GIS approach was applied to calculate the contribution of gullies to landscape scale greenhouse gas fluxes. Findings from the Moor House National Nature Reserve in the UK showed that although gullies occupied only 9.3% of the total land surface, gullies accounted for 95.8% and 21.6% of the peatland net CH(4) and CO(2) respiratory fluxes, respectively. The implication of these findings is that the relative contribution of characteristic gully systems need to be considered in estimates of landscape scale peatland greenhouse gas fluxes.     

Uptake pathways and elimination of a nonionic surfactant in cod (Gadus morrhua L.)

The uptake and elimination of a labelled surfactant, the nonionic nonylphenol ethoxylate, was studied in cod (Gadus morrhua L.) exposed to a concentration of 5 ppm. The amount of labelled surfactant was analyzed by the scintillation counting method in various tissues from the fish. A penetration especially through the gills, but also some intestinal resorption was found. Eight hours from start a steady state condition was obtained. High concentrations were found especially in gall bladder and liver. The elimination process in clean sea water was quite rapid and after 24 h the residues     

The use of Bacillus thuringiensis var. israelensis to control the nuisance fly Sylvicola fenestralis (Anisopodidae) in sewage filter beds

The effectiveness of using the microbial insecticide Bacillus thuringiensis var. israelensis (Bti) to control the nuisance fly Sylvicola fenestralis at Rossendale Sewage Works, Lancashire, was investigated. Following a provisional trial in 1987, the whole Works (28 filter beds) was treated with a two-stage application of Bti in 1988; the first application in late April was separated from the second in late May by about half the length of the Sylvicola life-cycle. The Bti treatment was timed to reduce fly nuisance in June, the month when most complaints (71%) had been received. For each application, 0.161. of the Bti preparation, containing nearly 10¹⁰ spores·cm⁻³, was applied per square metre of bed surface. An 80 and 98% kill of Sylvicola larvae was recorded following the first and second applications respectively. The lower kill achieved by the first application was believed to be due to insufficient mixing of the Bti with the settled sewage prior to dosing. Nuisance caused by the flies was considerably reduced; there were no complaints from the public during June, although a few were received in late July, early August. Sewage purification efficiency was not affected by Bti treatment. The maximum concentration of Bti spores in the Works' effluent was 7 × 10⁴ spores·cm⁻³. This concentration did not appear to affect the already impoverished macro-invertebrate fauna of the receiving river.     

Studies on the toxicity of copper sulphate to stone loach Noemacheilus barbatulus (L.) in hard water

The toxicity of copper sulphate to Noemacheilus barbatulus was studied for 64 days in a water of total hardness 249 mg l⁻¹ as CaCO₃. The 63-day lc₅₀ was approximately 0.25 mg Cu l⁻¹. Larger fish survived longer, and at concentrations greater than 0.29 mg l⁻¹ fish hid less during daylight. Noemacheilus surviving 0.12 mg Cu l⁻¹ for 64 days shed copper when placed in clean water for 7 days: gill, muscle, eye and vertebrae lost significant amounts of copper during this period. The opportunity to shed copper during a short period when the poison supply to their tank failed, may have allowed fish exposed to 0.49 mg l⁻¹ to live 12 days longer than expected. The sensitivity of Noemacheilus to copper, cadmium and zinc was compared with that of rainbow trout. Salmo gairdneri.     

The apparent and potential effects of climate change on the inferred concentration of dissolved organic matter in a temperate stream (the Malse River,South Bohemia)

Long-term and seasonal changes in concentration of dissolved organic matter (DOM) and their possible drivers were evaluated for an upland stream in central Europe during 1969-2000. Two periods have been detected within this data set-years with decreased DOM until the middle of 1980s and then years with increased DOM until 2000. Temperature, hydrological regime of runoff from the catchment (namely the amount of interflow), and changes in atmospheric deposition of acidity coincided with the variations in DOM concentrations. The analysis of single runoff events confirmed the relation between the export of increased DOM concentrations from the catchment and interflow. A multiple linear regression model based on monthly averages of temperature and interflow explained 67% of DOM variability. This model suggested a 7% increase in DOM concentration under the scenarios of possible future climate change related to doubled CO(2) concentration in the atmosphere. The scenarios were based on results of several global circulation models.     

Changes in bimodal oxygen uptake of an obligate air breather Anabas testudineus (Bloch) exposed to lindane

Bimodal [aquatic (V_O2) and aerial (V_O2)] oxygen consumption of the air-breathing fish, Anabas testudineus (Bloch) exposed to 0.075 and 0.59 mg 1⁻¹ lindane was measured for 120 and 6 h respectively. In the controls 67.9% of O₂ was obtained from air (V_O2) whereas only 32.1% was obtained from water (v_O2) indicating that A. testudineus predominantly relies on aerial gas exchange. The fish held in both the concentrations of lindane showed a consistent increase in v_O2, V_O2 and (v + V)_O2 (total O₂ consumption) in most of the periods of exposure; but the increases observed in mean O₂ consumption at higher concentration were relatively lower than those in lower concentration. In 0.075 mg 1⁻¹ lindane, the stimulation seen in aerial respiration was more than that in aquatic respiration up to 24 h. The oxygen consumption returned to normal at 96 h in the lower concentration of lindane.     

Temporal dynamics of dissolved and particulate organic carbon in the northern Adriatic Sea in relation to the mucilage events

The accumulation of dissolved and particulate organic matter may play an important role in mucilage formation in the northern Adriatic. Distributions of dissolved and particulate organic carbon were therefore investigated during the period June 1999-July 2002, when massive mucilage events occurred: in the summer of 2000 and, to a greater extent, of 2002. The seasonal variations in dissolved organic carbon (DOC) concentrations were significant, doubling in summer (up to 150 micromol L(-1)) with respect to winter. The particulate organic carbon (POC) variations were also very large, with a less pronounced seasonal pattern compared to DOC, because the POC changes are much more dependent both on river discharges and on phytoplankton blooms. The comparison of the concentrations between the period before (March-May) and after the onset of mucilage events (June-August) showed that DOC, but particularly POC, were higher in the period before the event of 2002, more markedly in the surface waters of low salinity. The POC increased, reaching mean concentrations of up to 36 micromol L(-1) in March 2002 before the outbreak of the massive mucilage formation in June. This suggests that POC may have a more important role in the mucilage formation than DOC. The highest seasonal variations of organic matter concentrations took place in the upper layer of lower salinity, stressing the importance of stratification and pycnoclines for accumulation and aggregation of the organic matter in the northern Adriatic. The POC contribution to the total organic carbon was low in the oligotrophic waters (DOC/POC ratio >15) and increased with the phytoplankton biomass in the productive waters (DOC/POC ratio <10). Particulate organic carbon predominated over the dissolved inside the mucilage aggregate (DOC/POC ratio <1), probably because aggregation processes, in which colloidal organic carbon is involved, are important. The organic carbon within the aggregates reached a concentration of 13.6 mmol L(-1) which was about 100 times more than in the surrounding waters or in the waters when the mucilages were absent. This indicates that distributions of organic carbon in the northern Adriatic can be extremely patchy during mucilage events.     

Biodegradability determinations via unspecific analyses (chemical oxygen demand, dissolved organic carbon) in coupled units of the OECD confirmatory test—II. Results

The coupled units test, described in detail in a previous paper, was applied to the biodegradability evaluation of compounds important to the detergent industry: some typical anionic and nonionic surfactants and mono- and polymeric organic phosphate substitutes. The results are compared with those obtained in other biological tests by other means.     

Use of biodegradable dissolved organic carbon (BDOC) to assess the potential for transformation of wastewater-derived contaminants in surface waters

Wastewater-derived contaminants (WWDCs), such as steroid hormones, pharmaceuticals and personal care products, have been detected in surface waters at concentrations that pose potential risks to aquatic ecosystems. To assess the factors controlling biotransformation of these compounds in effluent-dominated surface waters (i.e., surface waters containing a high proportion of wastewater effluent), microcosm experiments were conducted with 10 pharmaceuticals and five steroids typically detected in wastewater effluent. Some of the compounds underwent rapid biotransformation under all conditions (estrone, 17beta-estradiol, progesterone, testosterone and triclosan), while carbamazepine was always resistant to biotransformation. For the remaining compounds, the rate of biotransformation was related to the amount and type of biodegradable dissolved organic carbon (BDOC). The rates of biotransformation of these WWDCs increased as the initial concentration of wastewater BDOC increased, indicating a relationship between microbial activity and biotransformation rate. Furthermore, BDOC derived from aquatic plants resulted in a better ability to remove certain recalcitrant compounds (gemfibrozil and sulfamethoxazole) as compared to that derived from wastewater effluent. These observations indicate that for each source of BDOC, it may be possible to use BDOC for predicting the rate of biotransformation of WWDCs in surface waters.