Sediment wetlands

In random samples of soil taken from five Alabama counties, only 3 of 46 soil samples contained methyl parathion. The concentration in these samples was <0.1 ppm (Albright et al. 1974). Aspartofthe National Soils Monitoring Program, soil and crop samples from 37 states were analyzed for methyl parathion during 1972. Methyl parathion was detected in only 1 soil sample, at a concentration of <0.1 ppm and taken from South Dakota, out of 1,246 total samples taken from the 37 states (Carey et al. 1979). In soil and sediment samples collected from a watershed area in Mississippi, methyl parathion was not detected in the soil samples. In three wetland sediment cores, however, measurable concentrations of methyl parathion were detected during application season (Cooper 1991). 

Choi, J.H., Park, S.S., and Jaffe, P.R., The effect of emergent macrophytes on the dynamics of sulfur species and trace metals in wetland sediments, Environmental Pollution, 140, 286-293, 2006. 

Li J, Gu J-D (2006) Biodegradation of dimethyl terephthalate by Pasteurella mul-tocida Sa follows a novel biochemical pathway. Ecotoxicol 15 391-397 Li J, Gu J-D (2007) Complete degradation of dimethyl isophthalate requires the biochemical cooperation between Klebsiella oxytoca Sc and Methylobacte-rium mesophilium Sr isolated from wetland sediment. Sci Total Environ 380 181-187... 

Ellis et al. (2003) reduced Se(Vl) with anaerobic sediment slurries in order to approximate conditions in natural wetlands. Sediments and waters from the northern reach of the San Francisco estuary, the San Luis Drain, and a man-made wetland, all in California, were used. Reduction was apparently carried out by microbes, as autoclaved control experiments exhibited little reduction. Despite differences between the sediments and concentrations of Se(Vl) used in the various experiments, ese(vi)-se(iv) varied little, from 2.6%o to 3.1%o. The starting Se(Vl) concentrations of three experiments ranged from 230 nmol/L to 430 nmol/L that of a fourth experiment was much greater, at 100 pmol/L. Thus, it appears based on these few data that signihcant Se isotope fractionations persist to very low concentrations, though extrapolation to seawater concentrations (e.g., 1 nmol/L) would be risky. 

Ellis et al. (2003) obtained an Sse(iv)-se(o) range for Se(lV) reduction of 5.5%o to 5.7%o in three experiments with two of the three sediment slurries used for the Se(Vl) reduction experiments reviewed above. Se(lV) concentrations were 100 pmol/L and 240 nmol/L for the estuarine sediment experiments and 460 nmol/L for the wetland sediment. As with the Se(Vl) reduction experiments from this study, there was no apparent dependence on Se concentration or sediment type, though the number of experiments was small. 

Wetland remediation involves a combination of interactions including microbial adsorption of metals, metal bioaccumulation, bacterial oxidation of metals, and sulfate reduction (Fennessy Mitsch, 1989 Kleinmann Hedin, 1989). Sulfate reduction produces sulfides which in turn precipitate metals and reduce aqueous metal concentrations. The high organic matter content in wetland sediments provides the ideal environment for sulfate-reducing populations and for the precipitation of metal complexes. Some metal precipitation may also occur in response to the formation of carbonate minerals (Kleinmann Hedin, 1989). In addition to the aforementioned microbial activities, plants, including cattails, grasses, and mosses, serve as biofilters for metals (Brierley, Brierley Davidson, 1989). 

Fox, P.M. and Doner, H.E. (2003) Accumulation, release, and solubility of arsenic, molybdenum, and vanadium in wetland sediments. Journal of Environmental Quality, 32(6), 2428-35. 

While atrazine degradation to hydroxyatrazine was enhanced by the addition of ammonium sulfate in anaerobic wetland sediments (Chung et al., 1995), the addition of 2.0g/L of ammonium nitrate into aerobic wetland water sample reactors clearly inhibited atrazine degradation (Ro and Chung, 1995). In 15N tracer studies done with Pseudomonas strain ADP (which can use all five N atoms of atrazine as a sole N source), Bichat et al. (1997) indicated that while organic N sources had little effect on atrazine degradation, nitrate and ammonium delayed atrazine degradation. 

Oxygen deficiencies under field conditions have been reported to retard. v-triazine degradation. For example, Ro and Chung (1995) reported that in wetland sediments amended with nutrients, lOppm of atrazine reduced to less than lOppb within 3 weeks under aerobic conditions. Under anaerobic conditions, less than 50% degradation was reported in 38 weeks. However, Kruger et al. (1996) reported an opposite observation for a saturated soil where a 4-fold increase in degradation was reported. 

Ro, K.S. and K.H. Chung (1995). Atrazine biotransformation in wetland sediment under different nutrient conditions. 2. Aerobic. J. Environ. Sci. Health A-Sci. E, 30 121-131. 

Heim, S., J. Schwarzbauer, A. Kronimus, R. Littke, C. Woda, and A. Mangini. 2004. Geochronology of anthropogenic pollutants in riparian wetland sediments of the Lippe River (Germany). Org. Geochem. 35 1409-1425. 

Chanton, J.P., Martens, C.S., and Kelley, C.A. (1989a) Gas transport from methane-saturated, tidal freshwater and wetland sediments. Lirnnol. Oceanogr. 34, 807-819. 

Y. Q. Zhang, J. N. Moore, Changes in selenium speciation in wetland sediments induced by laboratory testing, Commun. Soil Sci. Plant., 28 (1997), 341-350. 

Fyson, A., M. Kalin, and L. W. Adrian. 1994. Arsenic and nickel removal by wetland sediments. In Proceedings of International Land Reclamation and Mine Drainage Conference and Third International Conference on the Abatement of Acidic Drainage. Pittsburgh, PA, pp. 1 and 109. 

Roden, E. E. Wetzel, R. G. (1996). Organic carbon oxidation and suppression of methane production by microbial Fe(III) oxide reduction in vegetated and unvegetated freshwater wetland sediments. Limnology and Oceanography, 41, 1733-48. 

Morris,., and Bradley, P. (1999). Effects of nutrient loading on the carbon balance of coastal wetland sediments. Limnol. Oceanogr. 44, 699-702. 

Nutfle, W., and Harvey,. W. (1995). Fluxes of water and solute in a coastal wetland sediment. I. The contribution of regional groundwater discharge. J. Hydro 164, 89—107. 

King G. M. (1990a) Dynamics and controls of methane oxidation in a Danish wetland sediment. FEMS Microbiol. Ecol. 74, 309-324. 

Roden E. E. and Wetzel R. G. (2002) Kinetics of microbial Ee(III) oxide reduction in freshwater wetland sediments. Limnol. Oceanogr. 411, 198-211. 

Sobolev D. and Roden E. E. (2003) Characterization of a neutrophihc, chemohthotrophic Fe(II)-oxidizing j8-proteo-bacterium from freshwater wetland sediments. Geomicrobiol. J. (in press). 

Because the fraction of organic material in porous media is rarely 100% and is typically less than 1% (notable exceptions exist in wetland sediments and peatlands), the partitioning of a hydrophobic organic compound between water and bulk soil can be estimated by the equation... 

Geochronology of a load history anthropogenic pollutants in riparian wetland sediments of the Lippe river (Germany) ... 

Bennion, H. et al. (2006) Further description of wetland sediment core analysis, Euro-limpacs Deliverable No. 100. 

Westerman, P., The effect of incubation temperature on steady-state concentrations of hydrogen and volatile fatty acids during anaerobic degradation in slurries from wetland sediments, FEMS Microbiol. EcoL, 13, 295-302, 1994. 

Geochemical analyses of the contaminated sediments in the root zone using sequential chemical extractions showed that greater than half of the arsenic is strongly adsorbed (Keon et al. 2000, 2001). A mixture of arsenic oxidation states and associations was observed and supported by bulk XANES and EXAFS data collected at the SSRL. Arsenic in the upper 40 cm of the wetland, which contains the peak corresponding to maximum deposition, appears to be controlled by iron phases, with a small contribution from sulfidic phases. The results suggest that iron oxide phases may be present in the otherwise reducing wetland sediments as a substrate onto which arsenic can adsorb, perhaps due to cattail root plaque formation. 

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