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Chromium, Copper, and Arsenic Concentrations in Soil Underneath CCA-Treated Wood Structures
Abstract
Soils below nine structures (decks and foot bridges) in Florida were examined to evaluate potential impacts from chromated copper arsenate (CCA), a common wood preservative. Eight of the nine structures were confirmed to have been treated with CCA. Soils collected were evaluated for arsenic, chromium, and copper concentrations as well as pH, volatile solids content and particle size distribution. Two types of soil samples were collected: a soil core and surface soil samples (upper 2.5 cm). One soil core was collected from below each deck and one control core was collected from an area removed from one of the structures. Eight or nine surface soil samples were collected in a grid-like fashion from beneath each structure. Equal numbers of surface control samples were collected from areas away from the structures. Metal concentrations were elevated in both the soil cores and surface samples collected from below the CCA-treated structures. Core samples showed elevated concentrations of metals at depths up to 20 cm. The arithmetic mean concentrations of arsenic, chromium, and copper in the 65 surface soil samples collected from below CCA-treated structures were 28.5 mg/kg, 31.1 mg/kg, and 37.2 mg/kg, respectively, whereas the mean concentrations of arsenic, chromium, and copper in the control samples were 1.34 mg/kg, 8.62 mg/kg, and 6.05 mg/kg, respectively. Arsenic concentrations exceeded Florida's risk-based soil cleanup target level (SCTL) for residential settings in all 65 surface soil samples. The industrial setting SCTL was exceeded in 62 of the 65 samples.
... Similarly, highway lumber and timbers (service life of 25 years on average) from CCA-treated wood are estimated to lose 46%, 21%, and 48% of the arsenic, chromium, and copper, respectively. The higher proportion leached of arsenic and copper relative to chromium is consistent with observations of leaching studies with CCA-treated wood (Moghaddam and Mulligan, 2008;Hingston et al., 2001;Townsend et al., 2003). In comparison to the copper-based formulations, residential lumber and timbers for ACQ treated wood lose 47%, from CBA treated wood lose 17%, and from the micronized formulations lose 13%. ...
Construction and demolition (C&D) wood can be recycled as mulch for landscaping or cogeneration. Limitations to such recycling are dependent on metals concentrations in mulch (As, Cu, and Cr) from the inclusion of waterborne-preservative treated wood. The objective of this study was to evaluate the amount of waterborne-preservative treated wood (by wood volume and by mass of metal) that enters the C&D wood waste stream in the U.S. by utilizing a mass balance approach. A model was developed using wood treatment industry production statistics, estimated leaching rates of metal-based preservatives, and typical service lives of wood products. Outputs of the model indicate that the volumes of waterborne preservative treated wood disposed of may exceed 16 million m ³ per year by 2030. The peak yearly metal mass disposed of corresponded to 18,400 metric tons for arsenic and 24,500 tons of chromium in 2013. Given the current trends in production, the mass of copper disposed of will increase to 20,900 tons by 2030. In order to meet regulatory guidelines regarding metals in recycled C&D wood, waterborne-preservative treated wood must be separated and removed. This separation mitigates environmental contamination from wood preservatives such as chromated copper arsenate (CCA).
... CCA is a waterborne treatment that utilizes copper and arsenic as biocides, while the While treating wood with CCA extends its service life, it also generates environmental and social impacts during its manufacturing, use, and disposal. Preservative metals make their way into soil and groundwater at manufacturing facilities, during use, and represent a significant risk when disposed of in unlined landfills (Hingston et al. 2001, Krietemeyer et al. 1997, Mercer and Frostick 2014, Townsend et al. 2003, Townsend et al. 2005). Laboratory leach rates for arsenic from preserved woods vary between 3% and 68% depending on conditions, e.g., sample dimension, test type, exposure time, and pH conditions (Townsend et al. 2004). ...
... In the introduction of our article ), we cited , , and others Townsend et al. 2003), who examined arsenic in soil and sand samples from the field or from the laboratory. These references provide the readers with useful background information on the sources and levels of potential arsenic exposure. ...
... Arsenic's toxic properties (WHO, 2011;ATSDR, 2017) and propensity to leach from CCA-treated wood (Khan et al., 2004(Khan et al., , 2006Townsend et al., 2004aTownsend et al., , 2005Shibata et al., 2006Shibata et al., , 2007Hasan et al., 2010) are well documented. Several studies focused on the impacts from leached wood (Townsend et al., 2003;Hemond and Solo-Gabriele, 2004) and potential exposure to children during play activities on CCA-treated structures (Kwon et al., 2004;Shalat et al., 2006;Barraj et al., 2009;Lew et al., 2010). In 1996, Tolaymat et al. (2000 endeavored to determine the proportion of CCA-treated wood in recycled C&D wood in Florida. ...
A limitation to recycling wood from construction and demolition (C&D) waste is contamination of metals from the inadvertent inclusion of preservative treated wood, in particular wood treated with chromated copper arsenate (CCA) and newer copper-based formulations. To minimize contamination many regions have developed best management practices (BMPs) for separating treated from untreated wood. The objective of this study was to evaluate the fraction of preservative treated wood in recycled C&D wood after the implementation of BMPs, using Florida as a case study. Methods involved collecting recycled C&D wood samples from throughout the state, measuring metals concentrations (As, Cu, and Cr) in the samples to compute the fraction of recycled wood treated with waterborne wood preservatives, and comparing measurements with those taken prior to the formalization of BMPs. Metals concentrations were measured using two methods, one based on traditional laboratory digestion methods and another using a more rapid hand-held X-ray Fluorescence (XRF) device in the field. The proportion of waterborne preservative-treated wood in recycled wood products has reduced significantly in the intervening 20 years (from 6% to 2.9%), and the fraction of CCA-treated wood has been reduced even further, to 1.4%. The remaining fraction of waterborne preservative-treated wood is comprised of new formulations of copper-based preservatives. This suggests that restrictions from the wood preservation industry and best management practices implemented at recycling facilities have been effective in reducing heavy metal contamination from pressure treated lumber in recycled wood products.
... The primary health concern is for young children in direct contact with CCA-treated wood, but localized leaching of arsenic (as well as chromium and copper) also occurs to surrounding soil. Soil arsenic concentrations of 37-250 mg/kg have been reported for soils sampled near CCA-treated utility poles (N = 12) (Pouschat and Zagury, 2006) and mean arsenic concentrations for soils collected below decks and footbridges in Florida, USA was reported to be 28.5 mg/kg compared with a control concentration of 1.3 mg/kg (N = 65) (Townsend et al., 2003). Arsenic from CCA contaminated soils appears to be more bioavailable than from other anthropogenic sources to soil (Juhasz et al., 2011). ...
This review is on arsenic in agronomic systems, and covers processes that influence the entry of arsenic into the human food supply. The scope is from sources of arsenic (natural and anthropogenic) in soils, biogeochemical and rhizosphere processes that control arsenic speciation and availability, through to mechanisms of uptake by crop plants and potential mitigation strategies. This review makes a case for taking steps to prevent or limit crop uptake of arsenic, wherever possible, and to work toward a long-term solution to the presence of arsenic in agronomic systems. The past two decades have seen important advances in our understanding of how biogeochemical and physiological processes influence human exposure to soil arsenic, and this must now prompt an informed reconsideration and unification of regulations to protect the quality of agricultural and residential soils.
... Further, the presence of wood preservatives may pose an environmental and human health risk due to release of toxic metals like arsenic and copper (Cu). Such an exposure pathway has already been recognized for various preservatives, in particular for chromated Cu arsenate (CCA) [1,2]. We are currently experiencing an increased use of particulate Cu wood preservatives in order to effectively protect wood from decay and lengthen its service life. ...
Background
We investigated the particles released due to abrasion of wood surfaces pressure-treated with micronized copper azole (MCA) wood preservative and we gathered preliminary data on its in vitro cytotoxicity for lung cells. The data were compared with particles released after abrasion of untreated, water (0% MCA)-pressure-treated, chromated copper (CC)-pressure-treated wood, and varnished wood. Size, morphology, and composition of the released particles were analyzed. ResultsOur results indicate that the abrasion of MCA-pressure-treated wood does not cause an additional release of nanoparticles from the unreacted copper (Cu) carbonate nanoparticles from of the MCA formulation. However, a small amount of released Cu was detected in the nanosized fraction of wood dust, which could penetrate the deep lungs. The acute cytotoxicity studies were performed on a human lung epithelial cell line and human macrophages derived from a monocytic cell line. These cell types are likely to encounter the released wood particles after inhalation. Conclusions
Our findings indicate that under the experimental conditions chosen, MCA does not pose a specific additional nano-risk, i.e. there is no additional release of nanoparticles and no specific nano-toxicity for lung epithelial cells and macrophages.
... Arsenic and hexavalent chromium are highly toxic to the living organisms including humans. Various studies have revealed that leaching of metals results from in-service CCA treated woods (Stilwell and Graetz, 2001;Townsend et al., 2003;Khan et al., 2006aKhan et al., , 2006b. The discarded CCA-treated wood contains high metal concentrations (Cooper et al., 2001). ...
... Copper-based preservatives are typically introduced as water-soluble salts, or in recent years as water-insoluble nanoparticulate copper salts (carbonates or oxides). The organic biocides and the water-soluble copper salts are known to leach from treated wood, especially in damp conditions such as when it rains or in sensitive wetland areas (68,69). Prior to this work there were no published studies on leaching of copper oxide/carbonate nanoparticles from treated wood. ...
This dissertation is related to the studies of functionalized nanoparticles for self-assembly and as controlled drug delivery system. The whole topic is composed of two parts. In the first part, the research was conducted to design and synthesize a new type of ionic peptide-functionalized copolymer conjugates for self-assembly into nanoparticle fibers and 3D scaffolds with the ability of multi-drug loading and governing the release rate of each drug for tissue engineering. The self-assembly study confirmed that such peptide-functionalized amphiphilic copolymers underwent different self-assembly behavior. The bigger nanoparticles were more easily assembled into nanoparticle fibers and 3D scaffolds with larger pore size, while the smaller nanoparticle underwent faster self-assembly to form more compact 3D scaffolds with smaller porosity but more stable structure. Controlled release studies confirmed the ability of governing simultaneous release of different model drugs with independent release rate from a same scaffold. Cytotoxicity tests showed that all synthesized peptides, copolymers and peptide-copolymer conjugates were biocompatible with SW-620 cell lines and NIH3T3 cell lines. This new type of self-assembled scaffolds combined the advantages of peptide nanofibers and versatile controlled release of polymeric nanoparticles to achieve simultaneous multi-drug loading and controlled release of each drug, uniform distribution and flexibility of hydrogel scaffolds.
The investigations in second part were first to design and synthesize organic biocide-loaded nanoparticles for low-leaching wood preservation using a cost-effective one-pot method to synthesize amphiphilic chitosan-g-PMMA nanoparticles loading with ~25-28 wt.% of the fungicide tebuconazole with particle size of ~100 nm diameter by FESEM. FESEM analysis confirmed efficient penetration of nanoparticles throughout the treated wooden stake with dimension of 19 × 19 × 455 mm^3. Leaching studies showed that biocide introduced into sapwood via nanoparticles leached only ~9% compared with the amount leached from tebuconazole solution-treated control, while soil jar tests showed that the nanoparticle-treated wood blocks were effectively protected from biological decay tested against G. trabeum, a brown rot fungus.
Copper oxide nanoparticles with and without polymer stabilizers were also investigated to use as inorganic wood preservatives to clarify the factor affecting copper leaching from treated wood. Copper oxide nanoparticles with uniform diameters of ~10 nm and ~50 nm were prepared, and the leachates from southern pine sapwood treated with these nanoparticles were analyzed. It was found by TEM and EDS analysis that significant numbers of nanoparticles leached from the treated wood. The 50 nm nanoparticles leached slightly less than a soluble copper salt control, but 10 nm nanoparticles leached substantially more than the control. The effect of polymer stabilizers on nanoparticle leaching was also investigated. Results showed that polymer stabilizers increased leaching. The trends showed that nanoparticle size was a major factor in copper leaching.
In the present study, efficacy of Copper-Ethanolamine-Boron (CEB) against white rot fungus has been evaluated. CEB (10%w/v) was tested at various concentration levels viz., 2.5 and 3% against white rot. From the results of the toxicity study, it was found that the lethal dose of CEB to control the attack of white rot was 2.5%. In India, this is the first report of utilising Copper Ethanolamine Boron in wood to control the wood destroying fungus i.e. white rot.
To gain an appreciation for the basic engineering principles is critical to environmental management professionals due to the breadth and complexity of environmental problems. This chapter provides an introduction to engineering in environmental management, with an emphasis on environmental engineering. Following a brief discussion on engineering and environmental management, the concepts of materials and energy balances, which are the basic tools for understanding environmental processes and solving environmental problems, are first introduced. Thereafter, water resources, municipal solid waste management, and air resources in environmental engineering are discussed in details. Theory and design issues are integrated in the topics on physical, chemical, and biochemical operations and processes.
The objective of this study was to establish baseline concentrations for 15 potentially toxic elements (Ag, As, Ba, Be, Cd, Cr, cu, Hg, Ma, Mo, Ni, Pb, Sb, Se, and Zn) based on 448 representative Florida surface soils using microwave assisted HNOâ-HCl-HF digestion. Baseline concentrations of those elements were (mg kgâ»Â¹): Ag 0.07-2.50, As 0.02-7.01, Ba 1.67-112, Be 0.04-4.15, Cd 0-0.33, Cr 0.89-80.7, Cu 0.22-21.9, Hg 0.00075-0.0396, Mo 0.13-6.76, Ni 1.70-48.5, Pb 0.69-42.0, Sb 0.06-0.79, Se 0.01-1.11, and Zn 0.89-29.6, respectively. Upper baseline values for most elements corresponded with these reported in literature, except Ba, Hg, Mn, Sb, and Zn, which were 3 to 23 times lower. Soil properties, including pH, organic carbon (OC), particle size, cation-exchange capacity (CEC), available water, extractable base, extractable acidity, total Ca, Mg, P, K, Fe, and Al concentrations, were related to metal concentrations using factorial analysis. Eight factors were identified (total Fe and Al, CEC, pH, clay, OC, total Ni and Mo, total Sb and Pb, and total Hg) and accounted for 87% of the total variance, suggesting that metal concentrations were primarily controlled by soil compositions. Multiple regression of elemental concentrations against total Fe, total Al, clay, OC, CEC, and pH was significant for all elements. Partial correlation coefficients indicated that total Fe and/or Al explained most of the variance for Mn, Ni, Ba, Be, Hg, As, Cd, Cr, Cu, Mo, Pb, and Zn concentrations. Most of the variance in Se was related to clay, whereas those of Ag and Sb related to clay and total Al.
Metals leached from chromated copper arsenate (CCA)-treated wood, taken up by epibiota and trophically transferred to their motile consumers or taken up directly by the consumers, were measured in caged organisms exposed to treated and untreated wood panels for 3 months. Epibiota on treated panels had more copper and arsenic than epibiota on untreated panels, and amphipods living on the former had elevated copper. However, metal concentrations in grass shrimp (Palaemonetes pugio) and two teleost fish, the naked goby (Gobiosoma bosci) and mummichog (Fundulus heteroclitus), were unaffected by CCA-treated wood exposure. In addition, there was no evidence of biomagnification in the consumers other than the amphipods. Thus, trophic transfer was not demonstrated to the consumers, suggesting that the treated wood was not presenting a hazard to higher trophic levels. Fish may have more efficient mechanisms for regulating metal levels in their tissues. ©
Oysters living on chromated copper arsenate (CCA)-treated wood in a residential canal were compared with oysters from a reference site 1.2 km away. Canal oysters were frequently green in color and had 15 times more copper (≈ 200 μg/g wet wt.) and 2–3 times more arsenic (≈ 3 μg/g) than reference oysters. Histological examination of soft tissues showed significantly more metaplastic degeneration in digestive gland diverticula of canal oysters. Giemsa-stained canal oyster gill cells had twice as many micronuclei as did reference oyster gill cells.Reference oysters caged by the CCA-treated wood in the canal had Cu tissue accumulations approaching that of native canal oysters by three months. These did not show increased digestive gland metaplasia but did have a nearly doubled incidence of micronuclei.Cu has been shown to cause digestive gland pathology in bivalves; thus, the treated wood could be responsible for the observed pathology. The Cr and As from the wood, although not accumulated to the extent of Cu, could influence the nonspecific response which was observed; Cr may also be responsible for the observed genotoxicity. Other possible Stressors in the canal (e.g. boat exhaust, gardening chemicals) could also be involved.
Wood represents approximately 25% of the C&D waste stream, and a possible limitation to wood recycling is the presence of CCA-treated wood. Research was performed to measure the percentage of chromated copper arsenate (CCA)-treated wood present in recovered wood stockpiles at construction and demolition (C&D) waste recycling facilities in Florida. Because of the elevated levels of chromium, copper, and arsenic in CCA-treated wood the presence of this material in C&D-recovered wood waste limits possible management options. Quantifying the fraction of C&D wood waste comprised of CCA-treated wood is a necessary first step in addressing this issue. Shredded wood samples were collected from the 12 C&D recycling facilities in Florida in an effort to quantify the fraction of recovered wood that was treated with the waterborne preservative CCA. The samples were further size reduced and mixed, and ultimately ashed at 550 degrees C in a laboratory furnace. Copper and chromium concentrations in the ash were measured using a flame atomic absorption spectrophotometer. These concentrations were used to calculate the amount of CCA-treated wood present in the original wood samples. The average percentage of 0.25-pcf standard retention, Type C, CCA-treated wood was estimated to be 6.5 % based on copper and 5.9 % based on chromium. In addition to providing needed measurements of CCA wood presence in C&D-recovered wood, this paper presents a methodology for estimating CCA wood amounts at other locations.