Comparative evaluation of NTA and EDTA for extractive decontamination of Pb-polluted soils

Nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) were compared for their ability to solubilize Pb from a highly-contaminated (PbT 21%) soil collected from a battery recycling facility. For chelant concentrations below 0.04 M (representing a 1:1 chelant-to-Pb_T molar ratio), EDTA released 10 to 30% more Pb than NTA. NTA-to-Pb T ratios greater than 1:1 reduced Pb recovery because of readsorption of Pb(NTA)₂ ^4? onto positively-charged oxide soil components at pH < 8.5. For the EDTA system, however, complexation completely bound all coordination sites of Pb and EDTA, leaving no functional groups available for surface adsorption. Thus, Pb recovery progressively increased with higher EDTA concentrations, although the additional Pb release with each EDTA increment became smaller. For pH < 5 and EDTA/Pb of 2:1, Pb recovery exceeded 90%. The addition of 0.5 M NaC1O₄ enhanced Pb recovery by EDTA for pH 5 to 12, but substantially suppressed recovery by NTA for pH < 11. Because Pb release by NTA was diminished by high ionic strength and chelant-to-metal ratios, NTA may be limited as a soil washing reagent. Stronger complexation and consistent Pb desorption behavior by EDTA favors its use.     

Potential transformations of chromium in natural waters

A study has been conducted on the transformation of Cr(III) and Cr(VI) in simulated natural water conditions. It has been found that these forms are readily interconvertible under natural water conditions. The results of this study indicate that Cr(VI) is reduced by Fe(II), dissolved sulfides, and certain organic compounds with sulfhydryl groups, while Cr(III) is oxidized by a large excess of MnO₂ and at a slow rate by Oz under conditions approximating those in natural waters. Based on the results of these studies, water quality standards for Cr should be based on total Cr rather than on Cr(VI), as has been frequently done in the past.     

Protozoa of a rotating biological contactor treatment plant in Mexico

A protozoological analysis of the biofilm developed on the discs of an RBC unit was performed using light microscopy; the species found belonged to 2 phyla: Sarcomastigophora with 23, and Ciliophora with 30 species. All isolates were free-living with the exception of Tritrichomonas fecalis. Most abundant species were: Euglena gracilis, Paramecium multimicronucleatum, Tetrahymena pyriformis, Polytoma uvella, Didinium nasutum, Bodo caudatus, Vorticella microstoma, Cyclidium glaucoma, Sathrophilus agitatus, Antophysa vegetans, and Urothrica farcta. Ciliates predominated over the flagellates in number and diversity. According to their locomotion most abundant species were free-swimming, followed by the attached, and crawling forms. In relation to their nutrition most frequent species were bacterivorous, saprozoic, and carnivorous. Values of the saprobic index calculated for each sampling station indicated that α-mesosaprobic conditions prevailed along the contactor with a zone of overlap with polysaprobic conditions at station IV. The RBC received an influent flow that varied from 1.5 to 13.5 L s^?1 and a soluble BOD₅ which range from 46 to 170 mg L^?1. The contactor studied showed an overall BOD₅ removal of 86% and a COD removal of 74%. DO levels influenced the values obtained for the saprobic index and the kind of protozoan populations and communities present. The biological findings (indicator species of the saprobic system), clearly reflected and agreed with the physicochemical results obtained simultaneously; the results showed that the system performed efficiently.     

A mechanism for hydrochloric acid production in cloud

A theoretical model describing the general interaction between atmospheric trace gases, such as S0₂, NH₃, C0₂ and 0₂, chemical reactant gaseous product H₂SO₄ and hydrometeors containing NaCl is proposed to study a possible mechanism for HCl production in non-precipitating cloud and the determination of the pH value of cloud droplets. Four different cloud droplet distributions have been used to estimate the upper limit of the amount of gaseous HCl released into the atmosphere resulting from the evaporation of cloud droplets. It is shown that the acid production and the amount of HCl released depend on the following factors: (a) the temperature of the cloud; (b) the oxidation rates; (c) the ambient concentration of SO₂, NH₃, and H₂SO₄; (d) the life cycle of the cloud; and (e) the liquid content of the cloud. This proposed chemical model also predicts a pH value spectrum depending on the cloud droplet distribution. Field measurements for the dependence of pH value on particle size and spatial distribution of gaseous HCl are recommended.     

Atmospheric pollution and fallout by PCBS and organochlorine pesticides (Ile-De-France)

Air pollution and atmospheric deposition by PCBs and organochlorine pesticides (isomers of HCH and p,p′-DDE) were studied at Paris from January 1986 to June 1987. The deposition measured as total (wet plus dry) was also followed during 1986 on two suburban and two rural sites. The distribution of the pollutants between the vapor phase and aerosols was evaluated by sampling air through a glass microfiber filter connected to a Tenax resin cartridge. The study shows that in the atmosphere as in waters of the catchment area of the Seine river, PCBs are the main organochlorine pollutants. Pollution by OCL is of the same order as the one described in literature (mean γ-HCH concentration 1.4 ng m^?3) while PCB concentrations in the atmosphere are equal to or higher than those observed in USA and Europe (range 5 to 44 ng m^?3). On the average, 93% of the PCBs are in the vapor phase with a composition approximating Aroclor 1242. In aerosols and precipitations the composition is closely related to Aroclor 1254. The total fallout for 1986 was 40 μg m^?2 for PCBs and 20 μg m^?2 for γ-HCH, rainfall being 611 mm.     

Influence of wetlands and coal mining on stream water chemistry

Comparisons of stream water chemistry over a 2 yr period in East Fork, which drains an entirely forested watershed, and Big Run, which drains a forested watershed 8 % of which is occupied by Big Run Bog, indicated that Big Run Bog had no effect on stream water H⁺ or Cl^? concentrations, but with increasing stream discharge the wetland was a source of Ca⁺⁺ Mg⁺⁺, K⁺, Na⁺, NO₃ ^?, and SO₄ ^?, and a sink for Fe^{+ +}. Further comparisons with Tub Run, which drains a forested watershed, 13 and 12% of which is occupied by Tub Run Bog and an abandoned, unreclaimed coal surface mine, respectively, suggested that Tub Run Bog removes H⁺, Ca ++, Mg⁺⁺, Fe⁺⁺, and 50₄ ^? from inputs of acid mine drainage. Wetland areas on the landscape contribute to the regulation of stream water chemistry in ways that are different from upland areas, and wetlands may have considerable applied potential for minimizing the impact of the mine drainage on stream water quality.     

Effect of simulated acid precipitation on nitrogen mineralization and nitrification in forest soils

After exposure of samples of three forest soils (pH 3.4 to 3.9) from the Adirondacks region of New York to 60, 230, or 400 cm of simulated rain of pH 3.5 or 5.6 in 4, 14, or 24 weeks, respectively, the soil samples were separated into the 0 to 2 and 2 to 5 cm organic layers and further incubated. The rates of N mineralization in Woods soil exposed to the simulated precipitation were less for rain at pH 3.5 than at pH 5.6, but the inhibition decreased with increasing exposure of the 0 to 2 cm layer. In Panther soil, the rates of mineralization were usually not affected by the acidity of the simulated rain. In the upper layer of Sagamore soil, mineralization was not influenced by pH of the simulated rain, but the transformation was faster in the bottom layer of soil after prolonged exposure to simulated rain at pH 3.5 than at pH 5.6. The rate of nitrate formation in Panther and Woods soil amended with ammonium was inhibited by the more acid rain. Studies with ¹⁵NH₄ indicated that ammonium was oxidized to nitrate even though ammonium levels did not decline or declined only slightly after prolonged exposure of Panther or Woods soil to rain at pH 3.5. The growth of orchardgrass in Panther and Woods soil was inhibited by the more acid simulated rain.     

Anthropogenic trace elements and polycyclic aromatic hydrocarbon levels in sediment cores from two lakes in the Adirondack acid lake region

Sediment cores were taken from the remote Sagamore and Woods Lakes in New York State's Adirondack acid lake region and analyzed for 3 to 7 ring polycyclic aromatic hydrocarbons (PAHs) and Ag, Al, As, Be, Cd, Cr, Cu, Hg, Ni, Ph, Se, Sn, TI, V, and Zn. With the exception of perylene, all of the parental PAHs, e.g. those without sidechains, and several of the metals, Pb, As, and Cd, were found to be significantly increased in the sediments of both lakes compared to their natural integrated deposits (ng cm^?2) and their background concentrations (μg g^?1 or ng g^?1 dry wt). Although the concentrations were generally much higher in Woods Lake, the total anthropogenic integrated depositions were about the same in both lakes for most of the metals and the 3 to 4 ring PAHs. The prime source of most of the 3 to 7 ring PAHs and trace elements measured is ascribed to anthropogenic combustion. Anthropogenically derived materials decreased in concentration with depth to baseline levels in sediment layers estimated by¹³⁷Cs analyses to be ～30 yr old, while biogenic or crustal derived species remained constant or fluctuated with core depth.     

Detailed early measurements of the fallout in Sweden from the chernobyl accident

Low-volume samplers collecting ambient aerosols in two size fractions have been used to collect radioactivity from the Chernobyl accident. The samplers were situated near light-houses on the east coast of Sweden and samples were collected during consecutive 12-hr periods. Activity concentrations of ⁹⁵Zr, ⁹⁵Nb, ^{103, 106}Ru, ¹³¹I, ^{134, 136, 137}Cs, ¹⁴⁰Ba, ¹⁴⁰La, ^141,144Ce, and ²³⁹Np were measured with a Ge(Li) detector. The transportation time between Chernobyl and the two sampling sites is in good agreement with times calculated from air mass trajectories. The main part of the radioactivity was found on particles with an aerodynamic diameter of less than 2 μm.     

Polychlorinated biphenyl uptake and translation by Spartina alterniflora loisel

This paper presents the findings of initial investigation of the role of Spartina alterniora Loisel. in the movement of chlorinated hydrocarbons. ¹⁴C-polychlorinated biphenyls and technical Aroclor® 1254 were used for the determinations. The findings demonstrate that Spartina accumulates ¹⁴C-radioactivity from sand and organic mud soil systems treated with ¹⁴C-PCB's. These findings also demonstrate that this plant has the capacity to accumulate ¹⁴C-radioactivity to levels elevated above that in the treated soil. Other experiments with Aroclor® 1254 demonstrate that cogeners of Aroclor® 1254 are present in Spartina stem and root extracts. These experiments also suggest that the chlorinated hydrocarbon uptake process is modulated by the plant and that this results in selective cogener uptake. The selectivity appears to be for the lesser chlorinated components of the commercial mixture. Overall, this study suggests that Spartina may act as an initial vector for mobilization of sediment bound chlorinated hydrocarbons to the estuarine food chain.     

Bioconcentration of HCH isomers by the ciliate protozoan,Tetrahymena pyriformis under laboratory conditions

Tetrahymena pyriformis, a common freshwater ciliate concentrated the four common HCH (Hexachlorocyclohexane) isomers viz., α, β, δ, and γ to varied extent. Bioconcentration factor [as expressed by the ratio of cellular insecticide in ng mg^?1 (dry weight) to supernatant in ng μL^?1 ranged from 342 to 2260 for α-HCH, 37 to 831 for β-HCH, 326 to 2806 for δ-HCH and from 106 to 1214 ppm for γ-HCH.     

Residues of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the Spring River,Missouri

Contamination of the Spring River in southwest Missouri by 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD) is believed to result from several well-defined point source waste disposal sites. Analyses of 31 fish samples and samples of crayfish, mussels, other aquatic invertebrates, and sediments collected in 1981-1983 demonstrated a rapid decline in TCDD levels in biota both upstream and downstream of the area of contamination and are believed to indicate a continuing, long term input of TCDD into the river. Mean concentrations of TCDD 0.5 km downstream from the area of contamination were 38 parts per trillion (pptr) in whole fish and 20 pptr in fish fillet; mean concentrations beyond 14 km downstream were below 4 pptr in both whole fish and fillets. Caged mussels (65 day exposure) did not accumulate TCDD (detection limit, 10 pptr). High fish consumption by local sportsmen may indicate maximum permissible concentrations of less than 5 pptr. in fish fillets.     

A comparison of a multilayer regional-scale acid rain assessment model (MLRAPT) with a single-layer assessment model,RAPT

This study, which is part of the 1985 Assessment on Current Damages of Acid Deposition, examines uncertainty due to treating transport processes using a single-layer model compared to a multilayer model. The Multilayer Regional Air Pollutant Transport Model, MLRAPT, was run in both modes, single layer and multilayer, using 224 sources during a 22-day period in July 1978 for the northeastern United States. Comparison between the two modes indicated that the average air concentrations were highly correlated (a correlation coefficient of 0.98). However, for wet deposition of SO₄, a correlation coefficient of 0.55 between the two predicted wet deposition fields was obtained. Results of the comparison of the two modes with the observed air concentration fields and with a limited comparison of observed wet deposition indicate that caution should be used when interpreting results of a single-layer model to develop source/receptor relationships.     

Amoebae in a waste stabilization pond system in Mexico

A protozoological survey was performed to analyze the organisms of the subphylum Sarcodina Schmarda, present in waste stabilization ponds located at Santo Tomás Atzingo, México, from March to December 1981. The amoebae isolated were identified and counted. Several physicochemical parameters were also determined and correlated with the biological data. Thirteen amoebic species were isolated and identified: one definite pathogen, Entamoeba histolytica Schaudinn; three species that have shown pathogenic strains for humans: Acanthamoeba polyphaga Page, Acanthamoeba castellanii Douglas, and Naegleria sp. (Alexeieff) Calkins; two opportunist species: Entamoeba coli (Grassi) Casagrandi and Barbagallo, and Iodamoeba bühschlii (Von Prowazek) Dobell; and seven free-living amoebae: Acanthamoeba astronyxis Ray and Hayes, Amoeba proteus (Pallas) Leidy, Hartmannella exundans Page, Hartmannella vermiformis Page, Pelomyxa palustris Leidy, Vahlkampfia avara Page, and Vahlkampfia russelli Singh. A clear correlation between the number of amoebae and the temperature and alkalinity of the system was found. The removal capacity of the ponds for E. histolytica varied from 30 to 100% during the survey. The amoebae showed a succession in space and time in the system studied.     

Impact of New York state emission sources on class 1 areas

The ARL-ATAD (Air Resources Laboratory-Atmospheric Transport and Dispersion) Model is used to calculate trajectories of air parcels leaving New York City, Albany, and Buffalo airshed regions and terminating near Federally-mandated Class 1 areas in the Northeastern United States, for which visibility is protected from degradation under the Clean Air Act. The purpose of this study is to provide an estimate of the frequency of occurrence of trajectory end points terminating over or near these environmentally sensitive regions from data for a one year period. Results indicate that these regions are not substantially effected by the air parcels either on an annual or seasonal basis.     

Antibiotic resistant coliform and faecal coliform bacteria in drinking water

Coliform and faccal coliform were isolated from drinking water samples obtained from tap water (TW) and storage tanks (ST) in Baghdad city. All isolates were identified and tested for their resistance to twelve antibiotics. Bacterial identification revealed that Ent. cloacae and Kl. pneumoniae were the predominant organisms from TW and ST water samples, respectively. Overall, 66% of the isolates from TW and 38% from ST were resistant to one or more of the drugs tested. Ampicillin, Carbenicillin, Cefalotin and Colistin resistance in particular were more frequent among bacterial isolates. The overall frequency of multiple antibiotic resistance among bacterial isolates in TW and ST samples were 47% and 33%, respectively. All bacterial strains isolated from drinking water were sensitive to Rifampicin. Results demonstrated the need for periodical bacteriological examination of drinking water and restriction in the use of antibiotics in this country.     

The response of specific conductance to environmental conditions in the everglades National Park,Florida

The specific conductance of surface delivery waters to the Shark River Slough (Everglades National Park, Florida) has increased significantly since the completion of Levee 29 (L-29) and the S-12 water delivery system in the early 1960's. In order to document the response of specific conductance in the slough to changing environmental conditions, it was monitored continuously for a period of 12 mo at a location in central Shark approximately 17 km south of the water delivery site. In addition, variability in isoconductivity patterns throughout the slough was assessed by conducting biweekly surveys at 97 locations. Specific conductance was found to respond to a variety of natural and manmade environmental changes and proved to be an important management tool serving as an early indicator of potentially broad changes in water quality. Factors important in determining overall isoconductivity patterns in Shark Slough include:

1. the ionic composition of surface delivered to Shark Slough via the S-12 delivery structures.
2. the quantitative relationship between the amount of surface water delivered to the slough and the amount of precipitation falling directly upon the slough.
3. the effects of evapotranspiration and concentration of biological organisms during seasonal periods of extreme drawdown.

     

The effects of PCB's (Aroclors 1254 and 1016) on fertilization and morphology in Arbacia punctulata

This study examined the effects of exposing the eggs of the purple sea urchin (Arbacia punctulata) to two commercial polychlorinated biphenyl mixtures (PCB's), Aroclors 1254 and 1016, on fertilization through pluteus (larva) development. Eggs were exposed to various concentrations of the PCB's (0.5, 1.0, 5.0, and 10.0 mg L^?1) beginning 25 min prior to insemination, with continuous exposure post-insemination for the 72 hr observation period employed in this study. The PCB's were administered as a component of a filtered sea water (FSW) medium. A FSW control and a FSW-acetone conditioned control where used since acetone was utilized in a 49 : 1, acetone: PCB ratio, to emulsify the PCB's. Since Arbacia eggs cleave synchronously following insemination, the percentage of the eggs cleaving at 1.75 hr post-insemination was used to determine the fertilization efficiency. Pluteus development and morphology was assayed at 24 hr intervals. The results of the fertilization efficiency studies were tested using Chi square and Pearson's-Product-Moment-Correlation Coefficient (r) at a 95% level of confidence. The morphology data were treated with a two-tailed t-test (99% confidence level) and (r). Both PCB's affected fertilization efficiency with the Aroclor 1016 being an order of magnitude more toxic than the Aroclor 1254. Likewise, both Aroclors were toxic to the pluteus development process with Aroclor 1016 being the more toxic of the two mixtures. At the highest PCB level employed, Aroclor 1254 proved more lethally toxic than Aroclor 1016 although both treatment-groups exhibited more than 90% toxicity to the morphogenic process.     

Determination and reduction of phytotoxicity of two industrial waste effluents

The objectives of this study were to determine and to reduce phytotoxicity of two industrial effluents. Phytotoxicity of the treated and untreated samples was determined using millet seed germination test. The results of this and other studies showed that the test was reproducible and useful for effluent toxicity determination. Effluent sample I was from an industrial wastewater pretreatment plant and sample II was from a specialty chemical industry. Sample I was weakly acidic and sample II was alkaline. pH adjusted to 7 to 8 was found to have no effect in phytotoxin removal. Granular and powdered activated carbon effectively reduced phytotoxicity. Amberlite XAD-4 (nonionic polymeric adsorbent) and cation exchange resin had a partial effect. Anion exchange resin, silica gel, Sephadex G-75, and starch xanthate had no effect.     

Titanium oxide nanoparticle effects on composition of soil microbial communities and plant performance

We examined the effect of TiO₂ nanoparticles (NPs) on the growth of maize and soybean plants and associated soil microbial communities. Plants were grown in a greenhouse, and low levels of undoped or nitrogen-doped TiO₂ NPs were applied. Plant growth and nutrient content were determined, and effects of NPs on composition of soil microbial communities were examined using terminal restriction fragment length polymorphism analysis (TRFLP) of rDNA. We found no significant effects of TiO₂ NPs on plant growth, nutrient content, or the composition of bacterial communities within the rhizosphere. However, arbuscular mycorrhizal fungal communities were affected by application of undoped and nitrogen-doped TiO₂ NPs. This observation may be partially attributed to the small but significant TiO₂ NP uptake levels in the root tissues of both plants. Our results suggest that even low concentrations of TiO₂ NPs may influence some important groups of soil microbes, such as mycorrhizal fungi, but changes in the composition of microbial communities may not affect plant growth under conditions of adequate moisture and nutrients.