Natural Formation of Chloroform and Brominated Trihalomethanes in Soil

Hoekstra, Eddo J.; Leer, E.D.W.B. de; Brinkman, U.A.Th.

doi:10.1021/es980127c

Cited by 100 publications

(76 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…CHBr 3 has been found in the air of upper soil of a pristine spruce forest (Haselmann et al, 2000). However in soil air of rural areas, Hoekstra et al (1998) found no detectable concentrations of CHBr 3 , except after in-situ enrichment by KBr. This suggests the potential of soils containing elevated bromide, e.g.…”

Section: Introductionmentioning

confidence: 88%

Atmospheric bromoform at Mace Head, Ireland: seasonality and evidence for a peatland source

et al. 2005

View full text Add to dashboard Cite

Abstract. In situ atmospheric observations of bromoform (CHBr 3 ) made over a 2.5 year period at Mace Head, Ireland from May 2001-Dec 2003, including during the NAM-BLEX (North Atlantic Marine Boundary Layer Experiment) campaign, show broad maxima from spring until autumn and winter minima, with mixing ratios of 5.3+1.0 pptv (mid March -mid October) and 1.8+0.8 pptv (DecemberFebruary). This indicates that, unlike CHCl 3 , which has a summer minimum and winter maximum at Mace Head, local biological sources of CHBr 3 have a greater influence on the atmospheric data than photochemical decay during longrange transport. The emission sources are predominantly macroalgal, but we find evidence for a small terrestrial flux from peatland ecosystems, which so far has not been accounted for in the CHBr 3 budget. Sharp increases in CHCl 3 and CHBr 3 concentrations and decreases in O 3 concentrations occurred at night when the wind direction switched from an ocean-to a land-based sector (land breeze) and the wind speed dropped to below 5 ms −1 . These observations infer a shallow atmospheric boundary layer with increased O 3 deposition and concentration of local emissions of both CHCl 3 and CHBr 3 . The ratio of CHCl 3 / CHBr 3 varied strongly according to the prevailing wind direction; from 0.60+0.15 in south-easterly (100-170 • ) and northerly (340-20 • ) air to 2.5+0.4 in north-easterly (40-70 • ) air. Of these land-sectors, the south-easterly air masses are likely to be strongly influenced by macroalgal beds along the coast and the emission ratios probably reflect those from seaweeds in addition to land sources. The north-easterly airmasses however had an immediate fetch inland, which locally is comprised of coastal peatland ecosystems (peat bogs and coastal conifer plantations), previously identified as being strongCorrespondence to: L. J. Carpenter (ljc4@york.ac.uk) sources of atmospheric CHCl 3 under these conditions. Although we cannot entirely rule out other local land or coastal sources, our observations also suggest peatland ecosystem emissions of CHBr 3 . We use correlations between CHCl 3 and CHBr 3 during the north-easterly land breeze events in conjunction with previous estimates of local wetland CHCl 3 release to tentatively deduce a global wetland CHBr 3 source of 20.4 (0.4-948) Gg yr −1 , which is approximately 7% of the total global source.

show abstract

Section: Introductionmentioning

confidence: 88%

Atmospheric bromoform at Mace Head, Ireland: seasonality and evidence for a peatland source

et al. 2005

View full text Add to dashboard Cite

show abstract

“…A variety of volatile organochlorines (VOCls), such as chloroform, is produced in soil (Hoekstra et al, 1998;Keppler et al, 2002;Svensson et al, 2007b;Rhew et al, 2008;Albers et al, 2010). VOCls are also emitted by wildfires, geothermal sources (Lobert et al, 1999), marine sources (Laturnus et al, 1998), and plants in temperate forest ecosystems (Forczek et al, 2015).…”

Section: Input and Export From Vegetationmentioning

confidence: 99%

Chlorine Cycling in Terrestrial Environments

Montelius¹

2016

Linköping Studies in Arts and Sciences

View full text Add to dashboard Cite

Chlorinated organic compounds (Clorg) are produced naturally in soil. Formation and degradation of Clorg affect the chlorine (Cl) cycling in terrestrial environments and chlorine can be retained or released from soil. Cl is known to have the same behaviour as radioactive chlorine-36 ( 36 Cl), a long-lived radioisotope with a half-life of 300,000 years. 36Cl attracts interest because of its presence in radioactive waste, making 36 Cl a potential risk for humans and animals due to possible biological uptake. This thesis studies the distribution and cycling of chloride (Cl -) and Clorg in terrestrial environments by using laboratory controlled soil incubation studies and a forest field study. The results show higher amounts of Cl -and Clorg and higher chlorination rates in coniferous forest soils than in pasture and agricultural soils. Tree species is the most important factor regulating Cl -and Clorg levels, whereas geographical location, atmospheric deposition, and soil type are less important. The root zone was the most active site of the chlorination process. Moreover, this thesis confirms that bulk Clorg dechlorination rates are similar to, or higher than, chlorination rates and that there are at least two major Clorg pools, one being dechlorinated quickly and one remarkably slower. While chlorination rates were negatively influenced by nitrogen additions, dechlorination rates, seem unaffected by nitrogen. The results implicate that Cl cycling is highly active in soils and Cl -and Clorg levels result from a dynamic equilibrium between chlorination and dechlorination. Influence of tree species and the rapid and slow cycling of some Cl pools, are critical to consider in studies of Cl in terrestrial environments. This information can be used to better understand Cl in risk-assessment modelling including inorganic and organic 36 Cl.Keywords: chloride, organic chlorine, chlorination, dechlorination, 36Cl, risk assessment modelling SammanfattningKlorerade organiska föreningar (Clorg) bildas naturligt i mark och påverkar klorets kretslopp genom att de stannar kvar längre i marken. Detta stabila klor anses ha samma egenskaper som klor-36, som är en långlivad radioisotop med en halveringstid på 300 000 år. Klor-36 förekommer i olika typer av radioaktivt avfall och om klor-36 sprids i naturen finns det en potentiell risk för människor och djur genom biologiskt upptag. Syftet i denna avhandling är att öka kunskapen om fördelningen och cirkulationen av klorid (Cl -) och Clorg i terrestra miljöer med hjälp av studier i laboratoriemiljö samt en fältstudie i skogsmiljö. Resultaten visar att bildningshastigheten av Clorg är högst i barrskogsjord och rotzonen tycks vara en aktiv plats. Det finns också en större mängd Cl -och Clorg i barrskogsjordar än i betesmark och jordbruksmark. Den mest betydande faktorn som styr halterna av Cl -och Clorg är trädsort, medan geografiskt läge, atmosfäriskt nedfall, och jordmån är av mindre betydelse. Bildning och nedbrytning av Clorg sker med liknande hastigheter, men det tycks fin...

show abstract

“…9,10 Different pathways have been proposed for natural chloroform production. When incubating organic compounds (organic acids, glucose) with chloroperoxidase and hydrogen peroxide, chloroform was detected as the main reaction product.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Another proposed pathway is the formation of chloroform by decarboxylation of trichloroacetic acid that is itself product of chlorination of organic matter in soil or originates from atmospheric oxidation of chlorinated ethenes. 9 Recently, it was demonstrated that chloroform can also be produced from organic model substance in a Fenton-like process in the absence of chloroperioxidases. 15 For groundwater management and remediation, it is important to know to what extent chloroform in groundwater originates from natural sources.…”

Section: ■ Introductionmentioning

confidence: 99%

Demonstrating a Natural Origin of Chloroform in Groundwater Using Stable Carbon Isotopes

Hunkeler

Laier

Breider

et al. 2012

Environ. Sci. Technol.

View full text Add to dashboard Cite

Chloroform has been for a long time considered only as an anthropogenic contaminant. The presence of chloroform in forest soil and groundwater has been widely demonstrated. The frequent detection of chloroform in groundwater in absence of other contaminants suggests that chloroform is likely produced naturally. Compound-specific isotope analysis of chloroform was performed on soil-gas and groundwater samples to elucidate whether its source is natural or anthropogenic. The δ 13 C values of chloroform (−22.8 to −26.2‰) present in soil gas collected in a forested area are within the same range as the soil organic matter (−22.6 to −28.2‰) but are more enriched in 13 C compared to industrial chloroform (−43.2 to −63.6‰). The δ 13 C values of chloroform at the water table (−22.0‰) corresponded well to the δ 13 C of soil gas chloroform, demonstrating that the isotope signature of chloroform is maintained during transport through the unsaturated zone. Generally, the isotope signature of chloroform is conserved also during longer range transport in the aquifer. These δ 13 C data support the hypothesis that chloroform is naturally formed in some forest soils. These results may be particularly relevant for authorities' regulation of chloroform which in the case of Denmark was very strict for groundwater (<1 μg/L).

show abstract

Natural Formation of Chloroform and Brominated Trihalomethanes in Soil

Cited by 100 publications

References 20 publications

Atmospheric bromoform at Mace Head, Ireland: seasonality and evidence for a peatland source

Atmospheric bromoform at Mace Head, Ireland: seasonality and evidence for a peatland source

Chlorine Cycling in Terrestrial Environments

Demonstrating a Natural Origin of Chloroform in Groundwater Using Stable Carbon Isotopes

Contact Info

Product

Resources

About