Environmental mutagenicity and toxicity caused by sodium metabisulfite in sea shrimp harvesting in Piauí, Brazil

Sodium metabisulfite is used in marine shrimp harvesting to prevent the occurrence of black spots. Shrimps are soaked in a sodium metabisulfite solution in ice, which is disposed of in sewages that run into marine canals, creating an environmental hazard. This study evaluates the toxicity and mutagenicity caused by sodium metabisulfite in sea waters and sediments collected in a shrimp farm in Cajueiro da Praia (Luis Correia), state of Piauí, Brazil, using the Allium cepa assay. Water and sediment samples were collected in the dry and in the rainy seasons, in three sites: upstream the shrimp farm (Site 1), at the point sodium metabisulfite is discharged (Site 2), and 100 m downstream the farm (Site 3). Three sample dilutions were used (50%, 25% and 10%) for all samples. A negative control (well water) and a positive control (copper sulfate 0.0006 mg mL⁻¹) were used in each experiment. At the end of the 72-h exposure period, onion roots were measured and removed. Mutagenicity analysis included the determination of mitotic index, chromosomal aberrations and the detection of micronuclei; analysis of root size and mitotic index were used as an index of toxicity. The A. cepa assay revealed that the water and sediments samples collected in the Piauí coast contaminated with sodium metabisulfite induce toxicity. The results demonstrate that the assay may be used as a regular tool in the analysis of water parameters in shrimp farms in the coast of Piauí state, and in strategies to preserve the region’s marine ecosystem.     

Dietary exposure of juvenile common sole (Solea solea L.) to polybrominated diphenyl ethers (PBDEs): Part 1. Bioaccumulation and elimination kinetics of individual congeners and their debrominated metabolites

The uptake and elimination of six PBDE congeners (BDE-28, -47, -99, -100, -153, -209) were studied in juvenile common sole (Solea solea L.) exposed to spiked contaminated food over a three-month period, then depurated over a five-month period. The results show that all of the studied PBDEs accumulate in fish tissues, including the higher brominated congener BDE-209. Several additional PBDE congeners were identified in the tissues of exposed fish, revealing PBDE transformation, mainly via debromination. The identified congeners originating from PBDE debromination include BDE-49 and BDE-202 and a series of unidentified tetra-, penta-, and hepta- BDEs. Contaminant assimilation efficiencies (AEs) were related to their hydrophobicity (log K_ow) and influenced by PBDE biotransformation. Metabolism via debromination appears to be a major degradation route of PBDEs in juvenile sole in comparison to biotransformation into hydroxylated metabolites.     

Bioconcentration of two pharmaceuticals (benzodiazepines) and two personal care products (UV filters) in marine mussels (Mytilus galloprovincialis) under controlled laboratory conditions

Bioaccumulation is essential for gaining insight into the impact of exposure to organic micropollutants in aquatic fauna. Data are currently available on the bioaccumulation of persistent organic pollutants, but there is very little documentation on the bioaccumulation of pharmaceuticals and personal care products (PPCPs). The bioconcentration of selected PPCPs was studied in marine mussels (Mytilus galloprovincialis). The selected PPCPs were two organic UV filters, i.e., 2-ethylhexyl-4-trimethoxycinnamate (EHMC) and octocrylene (OC), and two benzodiazepines (BZP), i.e., diazepam (DZP) and tetrazepam (TZP). Laboratory experiments were performed in which M. galloprovincialis was exposed to these compounds either directly from water, for the less lipophilic substances (BZP) or via spiked food for lipophilic UV filters. M. galloprovincialis uptook and eliminated BZP following first-order kinetics. The biological half-life (t (1/2)) of TZP was 1.4?days, resulting in a bioconcentration factor of 64 and 99?mL?g(-1) dry weight (dw), respectively, for 2.3 and 14.5?μg?L(-1) of exposure, while the biological half-life (t (1/2)) of DZP was 0.4?days, resulting in a bioconcentration factor of 51?mL?g(-1) dw for 13.2?μg?L(-1) of exposure. The uptake of UV filter was rapid in mussels, followed by elimination within 24?h. EHMC increased from 15 to 138?ng?g(-1) dw in 1?h and decreased to 25?ng?g(-1) after 24?h for 11.9?μg?L(-1) exposure. OC reached 839?ng?g(-1) dw after 1?h and decreased to 33?ng?g(-1) after 24?h for 11.6?μg?L(-1) exposure. However, EHMC and OC were slightly accumulated in 48?h, i.e., 38 and 60?ng?g(-1) dw, respectively.     

Henry’s law constant measurements for formaldehyde and benzaldehyde as a function of temperature and water composition

Henry’s law constants H of formaldehyde and benzaldehyde were determined using a dynamic system based on the water/air equilibrium at the interface within the length of a microporous tube. The measurements were conducted over the range 273–293 K in (i) deionized water, (ii) 35 g L^?1 solution of NaCl simulating seawater and (iii) two nitric acid solutions, i.e. 0.63 and 6.3 wt%.In pure water, the obtained data were used to derive the following Arrhenius expressions: ln H = (6423 ± 542)/T ? (13.4 ± 2.0) and ln H = (6258 ± 280)/T ? (17.5 ± 1.0) for formaldehyde and benzaldehyde, respectively. The H values, calculated at 293 K from Arrhenius expressions cited above were the following (in units of M atm^?1): H = 5020 ± 1170 (formaldehyde), H = 47 ± 5 (benzaldehyde). The temperature dependence of H permits then to derive the solvation enthalpies for both compounds: ΔH_solv = ?(53.4 ± 4.5) kJ mol^?1 and ΔH_solv = ?(52.0 ± 2.3) kJ mol^?1 for formaldehyde and benzaldehyde, respectively.In 35 g L^?1 salt solution, the H values were 27–66% and 12–21% lower than their respective determinations in deionized water, for formaldehyde and benzaldehyde respectively. The observed salt effect was used to estimate the following Setschenow coefficients at 293 K for 0.6 M NaCl: formaldehyde (0.21) and benzaldehyde (0.09).In 6.3 wt% nitric acid solution, H values of benzaldehyde were approximately 30% higher than those found in pure water although no significant influence was observed for formaldehyde.Finally, our experimental data were then used to estimate the fractions of formaldehyde and benzaldehyde in atmospheric aqueous phase and their derived atmospheric lifetimes.     

主成分分析法在水节霉生长水体水质评价中的应用

基于SPSS主成分分析法对海浪河流域水节霉生长水体水质进行评价.在12月份,对海浪河流域10个断面的水质指标进行评价,结果表明,英雄桥和斗银河口断面污染较严重,主要污染物为氮和有机物,其余断面水质较好,基本满足功能需求;同时对水节霉惟一生长地河夹村大坝连续进行6个月的水质监测,结果表明,在冰封期的1～2月份,该断面污染...     

Fluorescence Verses Radioactivity Labeling for Lab-Scale Investigation of the Fate of Water-Soluble Polymers in Wastewater Treatment Plants

Water-soluble synthetic polymers are extensively used in cosmetics, detergents and paints. Many end up in wastewater and, later on, in wastewater-treatment plants. In order to gain an insight into their fate in such plants, fluorescence and radioactivity labelings were compared using a lab-scale reactor designed to mimic industrial conditions. Two fermentation media were considered, namely a mixture of E402 and E204 micro-organisms and an activated sludge collected from a water-treatment plant located in the south of France. A sample of low molar mass commercial poly(acrylic acid) (PAA) was labeled by radioactivity with tritium and by coupling the 6-aminofluorescein fluorescent dye. Labeled PAA-containing sludges were allowed to ferment. To monitor the fate of the polymers, aliquots of the fermented mixtures were withdrawn at selected times and centrifuged. Liquid and solid phases were analyzed by scintigraphy or UV spectrometry, depending of the labeling techniques. Both techniques led to similar distributions, c.a. 75% in the supernatant and 25% in the solid phase. Distributions remained constant during the biological tests. There was no degradation of the commercial PAA after aqueous size exclusion chromatography (SEC), in agreement with literature. These features showed that fluorescence-labeling can be used instead of the complex and expensive radiolabeling. The validated fluorescence-based method was then applied to a linear poly(acrylic acid) synthesized by ATRP and labeled with 6-aminofluorescein. There was no significant difference between the commercial and the linear poly(acrylic acid)s. In contrast, a linear PAA with 5% of tert-butyl ester repeating units was predominantly found in the solid phase although adsorption or absorption by micro-organisms could not be demonstrated. The method based on fluorescence labeling should be applicable to other water soluble polymers provided that the dye remains attached to the polymer as it was the case for the studied poly(acrylic acid)s.     

Spatial Distribution of Geobacteraceae and Sulfate‐Reducing Bacteria During In Situ Bioremediation of Uranium‐Contaminated Groundwater

Analysis of the physiological status of subsurface microbial communities generally relies on the study of unattached microorganisms in the groundwater. These approaches have been employed in studies on bioremediation of uranium‐contaminated groundwater at a study site in Rifle, Colorado, in which Geobacter species typically account for over 90 percent of the microbial community in the groundwater during active uranium reduction. However, to develop efficient in situ bioremediation strategies it is necessary to know the status of sediment‐associated microorganisms as well. In order to evaluate the distribution of the natural community of Geobacter during bioremediation of uranium, subsurface sediments were packed into either passive flux meters (PFMs) or sediment columns deployed in groundwater monitoring wells prior to acetate injection during in situ biostimulation field trials. The trials were performed at the Department of Energy's (DOE's) Rifle Integrated Field Research Challenge site. Sediment samples were removed either during the peak of Fe(III) reduction or the peak of sulfate reduction over the course of two separate field experiments and preserved for microscopy. Direct cell counts using fluorescence in situ hybridization (FISH) probes targeting Geobacter species indicated that the majority of Geobacter cells were unattached during Fe(III) reduction, which typically tracks with elevated rates of uranium reduction. Similar measurements conducted during the sulfate‐reducing phase revealed the majority of Geobacter to be attached following exhaustion of more readily bioavailable forms of iron minerals. Laboratory sediment column studies confirmed observations made with sediment samples collected during field trials and indicated that during Fe(III) reduction, Geobacter species are primarily unattached (90 percent), whereas the majority of sulfate‐reducing bacteria and Geobacter species are attached to sediment surfaces when sulfate reduction is the predominant form of metabolism (75 percent and 77 percent, respectively). In addition, artificial sediment experiments showed that pure cultures of Geobacter uraniireducens, isolated from the Rifle site, were primarily unattached once Fe(III) became scarce. These results demonstrate that, although Geobacter species must directly contact Fe(III) oxides in order to reduce them, cells do not firmly attach to the sediments, which is likely an adaptive response to sparsely and heterogeneously dispersed Fe(III) minerals in the subsurface. © 2013 Wiley Periodicals, Inc.     

Organizational and Operational Techniques for Relieving Manpower Shortages in Air Pollution Control Agencies

Many governmental air pollution control agencies are confronted with a shortage of manpower, both in terms of numbers of people and qualifications of available staff members. This paper discusses a number of techniques which may be used to relieve this manpower shortage. The techniques are discussed in terms of collaboration between state and local agencies; organizational structures which make maximum use of scarce categories of people; program policies which conserve the time of agency staff; operating schemes which save travel time and minimize skills required; and working tools that can be used to get the greatest production with available personnel.     

Kinetics of simazine advanced oxidation in water

Abstract

Comparison of the effects and kinetics of UV photolysis and four advanced oxidation systems (ozone, ozone/hydrogen peroxide, ozone/UV radiation and UV radiation/hydrogen peroxide) for the removal of simazine from water has been investigated. At the conditions applied, the order of reactivity was ozone < ozone/hydrogen peroxide < UV radiation < ozone/UV radiation and UV radiation/hydrogen peroxide. Rate constants of the reactions between ozone and simazine and hydroxyl radical and simazine were found to be 8.7 M^‐1s^‐1 and 2.1x10⁹ M^‐1s^‐1, respectively. Also, a quantum yield of 0.06 mol.photon^‐1 was found for simazine at 254 nm UV radiation. The high value of the quantum yield corroborated the importance of the direct photolysis process. Percentage contributions of direct reaction with ozone, reaction with hydroxyl radicals and direct photolysis were also quantified.     

The influence of environmental factors on the molluscicidal activity of Euphorbia milii latex

Abstract

The present study was undertaken to investigate the influence of biotic (snail size and presence of food during the test) and abiotic factors (temperature, water hardness and concentration of organic materials) on the molluscicidal activity of Euphorbia milii latex. Bioassays were conducted with B. glabrata (10 snails per concentration) and snail lethality was evaluated after 24 hr and 48 hr of exposure to lyophilized latex solutions. Neither the degree of water hardness, nor the presence of food during the test affected latex‐induced snail mortality. The snail size had a minor influence on E.milii‐induced snail lethality. Newly‐hatched (shell diameter ≤ 1mm) as well as young (3–8 mm) snails were slightly less susceptible than older (10–25 mm) mollusks. On the other hand, the molluscicidal effect of E.milii latex was modified by environmental factors such as temperature (i.e. LC₅₀ and LC₉₀ values were halved for every 10°C rise in temperature) and concentration of organic materials in the water (i.e. the higher the concentration of organic matter, the higher the LC₅₀ value). The efficacy of E.milii latex as a molluscicide can be modified by factors such as water temperature and concentration of organic materials, and to a lesser extent by snail size.