Trichloroacetic acid cycling in Sitka spruce saplings and effects on sapling health following long term exposure

Dickey, C. A.

doi:10.1016/s0269-7491(04)00004-1

Cited by 2 publications

(7 citation statements)

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“…Table 2 and Figures 1 and S2 show that the response of the lysimeters to changes in applied TCA occurred within the two week timescale between dosing and leachate collection. Once The permanent mineralisation of TCA applied in these radioactivity experiments and to the in situ soil lysimeters is likewise consistent with observations of permanent loss of TCA applied to the soil surrounding Sitka spruce seedlings (Heal et al, 2003a;Dickey et al, 2004).…”

Section: Resultssupporting

confidence: 83%

“…Details of the methodology as applied here to soil and aqueous samples have been extensively reported elsewhere (Heal et al, 2003b;Heal et al, 2003a;Dickey et al, 2004;Stidson et al, 2004a;Stidson et al, 2004b;Dickey et al, 2005). In brief, water or sieved soil samples were sealed in 20 mL headspace vials and heated at 100 C for 1.5 h to effect decarboxylation, and re-equilibrated at 60 C before CHCl 3 determination on a DB5 column held at 50 C. Any background CHCl 3 was accounted for by determining CHCl 3 in a parallel vial of sample equilibrated to 60 C only.…”

Section: Analysis Of Tcamentioning

confidence: 99%

“…On the other hand, there is also evidence that TCA applied to soils is readily destroyed (e.g. Heal et al, 2003a;Matucha et al, 2003a;Dickey et al, 2004;Matucha et al, 2007). The uncertainty in understanding soil-TCA relationships is exacerbated by the intrinsic heterogeneity of soil and associated difficulties in controlling soil parameters (Laturnus et al, 2005), and the use of different analytical methods which quantify different fractions of TCA within the soil (Dickey et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The uncertainty in understanding soil-TCA relationships is exacerbated by the intrinsic heterogeneity of soil and associated difficulties in controlling soil parameters (Laturnus et al, 2005), and the use of different analytical methods which quantify different fractions of TCA within the soil (Dickey et al, 2005). Resolving the uncertainty is important because controlled experiments confirm TCA"s toxicity to trees and aquatic macrophytes at, or close to, environmental concentrations (Schröder et al, 1997;Cape et al, 2003;Dickey et al, 2004;Hanson and Solomon, 2004;Lewis et al, 2004), and consequently TCA is subject to formal risk assessment (Peters, 2003).…”

Section: Introductionmentioning

confidence: 99%

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The production and degradation of trichloroacetic acid in soil: Results from in situ soil column experiments

et al. 2010

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Previous work has indicated that the soil is important to understanding biogeochemical fluxes of trichloroacetic acid (TCA) in the rural environment, in forests in particular. Here, the hydrological and TCA fluxes through 22 in situ soil columns in a forest and moorland-covered catchment and an agricultural grassland field in Scotland were monitored every two weeks for several months either as controls or in TCA manipulation (artificial dosing) experiments. This was supplemented by laboratory experiments with radioactively-labelled TCA and with irradiated (sterilised) soil columns. Control in situ forest soil columns showed evidence of net export (i.e. in situ production) of TCA, consistent with a net soil TCA production inferred from forest-scale mass balance estimations. At the same time, there was also clear evidence of substantial in situ degradation within the soil (~70% on average) of applied TCA. The laboratory experiments showed that both the formation and degradation processes operate on time scales of up to a few days and appeared related more with biological rather than abiotic processes. Soil TCA activity was greater in more organic-rich soils, particularly within forests, and there was strong correlation between TCA and soil biomass carbon content. Overall it appears that TCA soil processes exemplify the substantial natural biogeochemical cycling of chlorine within soils, independent of any anthropogenic chlorine flux.

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Section: Resultssupporting

confidence: 83%

Section: Analysis Of Tcamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The production and degradation of trichloroacetic acid in soil: Results from in situ soil column experiments

et al. 2010

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“…Both uptake routes for TCA into foliage have been demonstrated in seedling dosing experiments. For example, Matucha et al (2001) have shown translocation of TCA to the needles of Norway spruce seedlings via the roots and transpiration stream, while both root-only and foliage-only routes have been shown for Scots pine (Sutinen et al, 1997) and Sitka spruce seedlings (Cape et al, 2003 andDickey et al, 2004) These experiments have all involved small seedlings <5-6-year old, and consequent TCA doses per unit mass of tree higher than environmental. Although a few previous data exist for ambient below-canopy throughfall TCA concentration (Hoekstra, 2003), there are no data that quantify the TCA flux through a mature forest canopy exposed only to ambient TCA deposition fluxes.…”

Section: Introductionmentioning

confidence: 99%

Fluxes of trichloroacetic acid through a conifer forest canopy

Stidson

Heal

Dickey

et al. 2004

Environmental Pollution

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Controlled-dosing experiments with conifer seedlings have demonstrated an above-ground route of uptake for trichloroacetic acid (TCA) from aqueous solution into the canopy, in addition to uptake from the soil. The aim of this work was to investigate the loss of TCA to the canopy in a mature conifer forest exposed only to environmental concentrations of TCA by analysing above- and below-canopy fluxes of TCA and within-canopy instantaneous reservoir of TCA. Concentrations and fluxes of TCA were quantified for one year in dry deposition, rainwater, cloudwater, throughfall, stemflow and litterfall in a 37-year-old Sitka spruce and larch plantation in SW Scotland. Above-canopy TCA deposition was dominated by rainfall (86%), compared with cloudwater (13%) and dry deposition (1%). On average only 66% of the TCA deposition passed through the canopy in throughfall and stemflow (95% and 5%, respectively), compared with 47% of the wet precipitation depth. Consequently, throughfall concentration of TCA was, on average, approximately 1.4 x rainwater concentration. There was no significant difference in below-canopy fluxes between Sitka spruce and larch, or at a forest-edge site. Annual TCA deposited from the canopy in litterfall was only approximately 1-2% of above-canopy deposition. On average, approximately 800 microg m(-2) of deposited TCA was lost to the canopy per year, compared with estimates of above-ground TCA storage of approximately 400 and approximately 300 microg m(-2) for Sitka spruce and larch, respectively. Taking into account likely uncertainties in these values ( approximately +/- 50%), these data yield an estimate for the half-life of within-canopy elimination of TCA in the range 50-200 days, assuming steady-state conditions and that all TCA lost to the canopy is transferred into the canopy material, rather than degraded externally. The observations provide strong indication that an above-ground route is important for uptake of TCA specifically of atmospheric origin into mature forest canopies, as has been shown for seedlings (in addition to uptake from soil via transpiration), and that annualized within-canopy elimination is similar to that in controlled-dosing experiments.

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Trichloroacetic acid cycling in Sitka spruce saplings and effects on sapling health following long term exposure

Cited by 2 publications

References 0 publications

The production and degradation of trichloroacetic acid in soil: Results from in situ soil column experiments

The production and degradation of trichloroacetic acid in soil: Results from in situ soil column experiments

Fluxes of trichloroacetic acid through a conifer forest canopy

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