Laboratory studies of the marine copepod Centropages typicus: egg production and development rates

Egg production and development rates of Centropages typicus (Krøyer) were studied in the laboratory under carying food and temperature conditions. Egg production rates in the laboratory ranged from 0 to 124 eggs female^-1 d^-1 and increased with food concentration up to a critical food concentration (P_c) above which egg production was constant. Egg production rates were influenced by temperature, with more eggs being produced at 15°C than at 10°C. Thalassiosira weisflogii and Prorocentrum micans were determined to be equally capable of supporting egg production at concentrations above P_c at 15°C. Rate of egg production was independent of adult female size when food and temperature were constant. Egg production rates of freshly captured females ranged from 0 to 188 eggs female^-1 d^-1 and were higher in April and May than in June or July. Hatching rates of eggs increased with increased temperature; 95% of the eggs at 15°C hatched within 48 h, while only 8% of the eggs at 10°C hatched within 48 h. Development rates, determined at 10°C in excess concentrations of T. weisflogii, were 23.0 d from egg release to copepodid state I, 27.0 d to stage II, 29.5 d to stage III, 32.2 d to stage IV, 38.5 d to stage V and 49 d to adulthood based on the average time required for 50% of the organisms in an experiment to attain a given stage. Adult males were usually observed 2 to 4 d before adult females, and therefore have a slightly faster rate of development. The effects of temperature, food type and food concentration on egg production and the seasonal appearances of diatoms in the New York Bight may account for the observed seasonal cycles in abundance of C. typicus in these coastal waters.     

Cadmium bioaccumulation in organs of the scallopMizuhopecten yessoensis

Cadmium and Zinc content was determined in organs of the Japanese scallopMizuhopecten yessoensis, collected in 1984 from the Sea of Japan and aged between 1 and 8 yr. Under conditions of background Cd, Cd concentration in hepatopancreas and kidney increased linearly with age from 39 to 400µg g^?1 dry wt in hepatopancreas, and from 100 to 640µg g^?1 dry wt in kidney. Such a pattern was not determined for Zn. Cd concentration in muscle, mantle and gill did not exceed 6µg g^?1 dry wt in the oldest scallops. In subcellular fractions of the hepatopancreas, cytosolic Cd accounted for 71.7% in 1-yr-old scallops and 98.8% in 8-yr-olds. A similar ratio was established for gills, although gill Cd content was an order of magnitude lower. Analysis of Cd distribution in cytoplasmic proteins (of different molecular weight) in the hepatopancreas, showed that the amount of Cd bound to metallothionein-like proteins increases with scallop growth. A considerable amount of Cd also was detected in high molecular weight proteins. Thus, Cd accumulation, with age, in organs of the Japanese scallop is due to metal binding by cytoplasmic proteins.     

Adsorption of phenolic compounds by activated carbon--a critical review

Adsorption of phenol and its derivatives on activated carbons is considered based on numerous papers related to this issue. Special attention is paid to the effects of carbon surface functionalities, pH of solution and heterogeneity effects that accompany adsorption of phenolic compounds. Moreover, in this paper the most important aspects are overviewed referring to irreversible adsorption of phenols and impact of different substituents of phenolic compounds on their uptake by activated carbons is considered. Finally, some remarks pertaining to applications of novel adsorbents for phenol adsorption are discussed and illustrated by means of a few examples.     

Dissociation of sulfur hexafluoride tracer gas in the presence of an indoor combustion source

As an odorless, nontoxic, and inert compound, sulfur hexafluoride (SF6) is one of the most widely used tracer gases in indoor air quality studies in both controlled and uncontrolled environments. This compound may be subject to reactions with water vapor under elevated temperature to form acidic inorganic compounds such as HF and H2SO4. Thus, in the presence of unvented combustion sources such as kerosene heaters, natural gas heaters, gas log fireplaces, candles, and lamps, the SF6 dissociation may interfere with measurements of the emissions from these sources. Tests were conducted in a research house with a vent-free natural gas heater to investigate these potential interferences. It was observed that the heater operation caused about a 5% reduction of SF6 concentration, which can be an error source for the ventilation rate measurement and consequently the estimated pollutant emission rates. Further analysis indicates that this error can be much greater than the observed 5% under certain test conditions because it is a function of the ventilation flow rate. Reducing the tracer gas concentration has no effect on this error. A simple theoretical model is proposed to estimate the magnitude of this error. The second type of interference comes from the primary and secondary products of the SF6 dissociation, mainly H2SO4, SO2, HF, and fine particulate matter (PM). In the presence of approximately 5 ppm SF6, the total airborne concentrations of these species increased by a factor of 4-10. The tests were performed at relatively high SF6 concentrations, which is necessary to determine the interferences quantitatively. The second type of interference can be significantly reduced if the SF6 concentration is kept at a low ppb level.     

Distribution of selected heavy metals and rare earth elements in surficial sediments from the polish sector of the Vistula Lagoon

The concentrations of 22 trace elements plus the rare earth elements (REE) were determined in the <63 μm fraction of surficial sediments from the Polish sector of the Vistula Lagoon by ICP-MS. For the anthropogenically-enriched elements, the mean element enrichment factors (EF's) decrease in the sequence Ag (9.9) > Sb (7.5) >As (5.8) ≥ Cd (5.2) > Pb (3.7), albeit with large variability in concentration in the sediments from one station to another. These observations demonstrate that sediments from the Vistula Lagoon are locally polluted by these anthropogenically-derived elements. Plots of NASC-normalized REE data show that the REE patterns of the sediments have not been significantly modified during transport from their source with only a minor depletion of the heavy rare earth elements (HUE) compare to the light rare earth elements (LREE). The lack of any significant anomalies for Ce and Eu indicates that redox processes have not played a major role in modifying the distribution of the REE. Factor ananalysis of the compositional data shows that sediments from the Polish sector of the Vistula Lagoon can be divided into three main groups depending on the geographical location and the degree of contamination by heavy metals.     

Biological treatment of dye wastewaters using an anaerobic-oxic system

Three dye solutions, namely, C.I. Acid Yellow 17, C.I. Basic Blue 3, and C.I. Basic Red 2, were treated in an upflow anaerobic sludge blanket (UASB) reactor followed by a semi-continuous aerobic activated sludge tank. When hydraulic retention time was about 12 hours, no significant color removal was observed in the aerobic stage. In the anaerobic stage, Acid Yellow 17, Basic Blue 3, and Basic Red 2 were removed by 20%, 72%, and 78%, respectively. To treat wastewater from a dye manufacturing factory with COD concentration of 1200 mg/l and Color of 500 degree (dilution factor), an UASB reactor (4.5 liters) and an activated sludge tank (5 liters, adjustable), COD and color were removed by more than 83% and 90% at a COD loading rate of 5.3 kg COD/m³-day in the anaerobic stage, and at the hydraulic retention time of 6-10 hours for the anaerobic stage and 6.5 for the aerobic stage. The anaerobic stage of the A/O system removes both color and COD. In addition, it also improves biodegradability of dyes for further aerobic treatment.     

In vivo chronic effect of dimethoate and deltamethrin on rabbits

The in vivo effect of dimethoate and deltamethrin on body and organ weights, serum proteins and on plasma acetylcholinesterase (AChE), aromatic esterase and ATPase were examined in growing male rabbits throughout five months period. Both compounds had no significant effect on body weight; however, adrenal, testis & pituitary weights decreased (P less than 0.01); the liver and spleen weights increased (P less than 0.01) in a dose dependent manner. Serum total proteins and globulin decreased (P less than 0.01) in a dose dependent trend, while serum albumin was not greatly affected. AChE activity was increased (P less than 0.01) after 1 month of treatment with the two doses of dimethoate and deltamethrin; thereafter, AChE activity showed 40% inhibition of the control level. The activity of aromatic esterase increased markedly after the first month, then declined gradually until the fifth month. High dose of dimethoate markedly inhibited this enzyme particularly after the 5th month of treatment. Both doses of deltamethrin increased ATPase activity after the first month of treatment, then the ATPase activity was normal. Dimethoate inhibited ATPase particularly at the end of treatment in a dose dependent manner.     

Effects of metabolites of benzo(a)pyrene on unschedule DNA synthesis in BALB/3T3 cell line

In order to explore the damage from metabolites of benzo(a)pyrene on DNA of mammalian cells, the effects of four metabolites of benzo(a)pyrene (anti-BPDE, syn-BPDE, 3-OH-BP and 9-OH-BP) on synthesis of DNA and unschedule DNA synthesis (UDS) in BALB/3T3 cells were assayed, by methods of single-labeling and double-labeling. The results showed that all of the four agents were able to increase the synthesis of DNA, but only three of them (apart from syn-BPDE) induced UDS in BALB/3T3 cells. The above indicates that the metabolites of benzo(a)pyrene are able to damage DNA in BALB/3T3 cells, and that this effect may be relative to the sterical structure of metabolites of benzo(a)pyrene.     

Bioaccumulation and physiological effects of excess lead in a roadside pioneer species Sonchus oleraceus L

Seedlings of Sonchus oleraceus L. were transplanted to soil supplied with lead acetate at dosages of 0, 800, 1600 and 3200 mg kg(-1) DW. Measures of chlorophyll content, peroxidase (POD) activity, shoot length, biomass and Pb content in the plant tissues were obtained from the experimental plants. With increasing amounts of Pb in the soil, the chlorophyll content, shoot length and biomass decreased, while POD activity and Pb content in the plant tissues increased. At 3200 mg kg(-1) Pb treatment, Pb content in the plant leaf, stem and root were 65.67, 149.82 and 1113.24 mg kg(-1), respectively. Only at 3200 mg kg(-1) Pb treatment did chlorophyll content, shoot length and biomass significantly increase by 18, 15 and 44%, respectively, while POD decreased by 39% over the control. The potential of applying this species in phytoremediation of Pb contaminated roadside soils and thus restoration of the roadside vegetation are discussed.