Assessing the impacts of chemical cocktails on the soil ecosystem

Horswell, Jacqui; Prosser, J.A.; Siggins, Alma; Schaik, A. Van; Ying, Lucia; Ross, C. W.; McGill, A.; Northcott, Grant L.

doi:10.1016/j.soilbio.2014.03.013

Cited by 14 publications

(13 citation statements)

References 45 publications

(69 reference statements)

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“…Moreover, in the Horotiu soil, triclosan exposure resulted in a greater microbial biomass after 6 months of exposure. A concurrent study on the same lysimeter soils confirmed that a large proportion of triclosan disappeared over the 6 months of incubation (Horswell et al 2014). The dissipation of triclosan in the soils under laboratory conditions was rapid, with half-lives of 7.8 days in the Horotiu soil and 26 days in the Templeton soil, which after 3 months of incubation resulted in a reduction of triclosan concentrations by 95 % in the Horotiu soil and 80 % in the Templeton soil (Northcott 2014).…”

Section: Effects Of Triclosanmentioning

confidence: 80%

“…The soil was kept cool and immediately returned to the laboratory for lysimeter construction as previously described in Horswell et al (2014). Briefly, about 1 kg of each of the fresh soils was sieved to 4-mm particle size and soil moisture content and soil moisture content at field capacity were determined by drying a subsample at 105°C until no further weight change was observed.…”

Section: Soil Sampling and Triclosan Soil Treatmentsmentioning

confidence: 99%

“…These half-lives were in the same order of magnitude as Ying et al (2007), who reported a half-life of 18 days, and Xu et al (2009), who reported a half-life of 14 to 20 days. However, at high copper concentrations, 26 % of the applied triclosan remained in the Horotiu soil after 6 months, suggesting a half-life of about 90 days (Horswell et al 2014). Triclosan degradation was also slower (104 days) when triclosan-containing biosolids were applied on land (Lozano et al 2012).…”

Section: Effects Of Triclosanmentioning

confidence: 99%

“…Even though zinc exposure by itself did not have an effect on microbial biomass, exposure to triclosan in combination with the high rate treatment of zinc produced a decrease in microbial biomass. Horswell et al (2014) suggested that high concentrations of zinc or copper inhibited the ability of soil microbes to degrade triclosan thereby causing a greater effect when both zinc and triclosan were present. In both oral and nutrient-rich soil environments, similar interaction effects were observed whereby microbial biomass and metabolic activities were more affected when microbial communities were exposed to a combination of zinc and triclosan than each individually (Brading et al 2003).…”

Section: Effects Of Triclosan and Zincmentioning

confidence: 99%

“…This transformation product has some similar modes of action as triclosan (Hinther et al 2011) but has a higher potential to bioaccumulate than the parent compound (DeLorenzo et al 2008;Lindström et al 2002). The degradation of triclosan in the soil is also affected by the presence of copper and zinc (Horswell et al 2014) and is observed to be readily biodegradable under aerobic but not anaerobic conditions in soils (Ying et al 2007) and during sewage treatment processes (McAvoy et al 2002). Despite the biodegradability of triclosan during aerobic sewage treatment, sorption to sewage solids is the principal mechanism by which triclosan is removed from wastewater, with adsorption to primary sludge typically accounting for 40 to 90 % of the total removal (McAvoy et al 2002;Thompson et al 2005;Heidler and Halden 2007).…”

Section: Introductionmentioning

confidence: 99%

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Effect of copper and zinc on microbial tolerance to triclosan in two soil types

et al. 2016

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Purpose Sewage sludge and biosolid application to land is a common approach to fertilise soils, but sewage-derived contaminants like the antimicrobial agent triclosan, and heavy metals zinc and copper, are known to affect soil microbial communities. In this study, the tolerance to triclosan was examined for soil microbial communities chronically preexposed to one of two heavy metals (Cu or Zn) and the antimicrobial triclosan. This was investigated in two different soil types. Materials and methods The impacts of chronic exposure of copper, zinc and triclosan as individual compounds or in mixtures on soil microbial communities were assessed in soils collected from two sites. The first was a Horotiu sandy loam with ample carbon and nitrogen levels and the second was a Templeton silt loam with very low carbon and nitrogen levels. The end points used to characterise the response of the soil microbial community were biomass, metabolic activity and pollution-induced community tolerance (PICT) to triclosan (using Biolog EcoPlates). In addition, metabolic activities for individual substrates were examined and those that significantly changed with the applied treatments were identified. Results and discussion Exposure to mixtures of both triclosan and copper in the Horotiu sandy loam reduced microbial biomass, increased metabolic activity and reduced microbial tolerance to triclosan. The decrease in soil microbial tolerance correlated with an increased metabolic activity for N-acetyl-Dglucosamine providing a potential link between triclosan exposure and nitrogen mineralisation. Exposure to both triclosan and high zinc levels decreased microbial biomass in the Horotiu sandy loam but did not have an effect on microbial tolerance to triclosan. In the finer-textured and less fertile Templeton soil, microbial tolerance to triclosan and the microbial biomass were not impacted by copper/triclosan or zinc/triclosan mixtures. Conclusions Mixture effects could become a cause for concern when soil microbial communities are exposed to triclosan in fertile soils with copper concentrations in excess of 50 mg kg −1 and could be especially important in the more coarsely textured soils. Current regulations for soil contaminants only consider the risk and effects of single contaminants. Greater protection of soil resources could result from considering mixture effects and soil types.

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Section: Effects Of Triclosanmentioning

confidence: 80%

Section: Soil Sampling and Triclosan Soil Treatmentsmentioning

confidence: 99%