No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Accumulation of metals in consumers associated with chromated copper arsenate-treated wood panels
Abstract
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. ©
... The use of preservative-treated wood has been phased out for residential and aquatic applications due to its potentially adverse effects on humans and causing environmental contamination. Some ecotoxicological studies on wood treated with conventional preservatives including chromated copper arsenate (CCA) and CCA alternatives such as alkaline copper quats (ACQ) were carried out in the late 1990s-2000s, which later proved that the leachable compounds from the treated wood in-service were toxic to aquatic and soil organisms (Weis and Weis 1999;Turpeinen et al. 2004). Today, alternatives to conventional preservation methods, marketed as ''environmentally friendly'' or ''nontoxic'', are emerging. ...
Kapur (Dryobalanops sp.) and Japanese larch (Larix kaempferi) wood samples were heat-treated in air at 180°C for 24 and 48 h. Leaching and toxicity tests were conducted to determine the ecotoxicity effect of these heat-treated woods on the aquatic environment due to heat treatment. The toxicity of conventional preservative-treated woods, i.e. chromated copper arsenate (CCA) and ammo-niacal copper quat (ACQ), was also determined for comparison purposes. Acute toxicity tests were performed using two aquatic organisms, Daphnia magna and Vibrio fischeri according to the Organization for Economic Cooperation and Development standard procedures and Microtox assay, respectively. Significantly low toxicity to D. magna was found for the heat-treated Kapur compared to that of untreated Kapur, while heat-treated Japanese larch did not show any toxicity effect. As expected, ACQ-treated samples showed the highest toxicity to D. magna, followed by that of CCA, though toxicity of both preservative treated woods further reduced over time. Hence, heat treatment of Kapur and Japanese larch were believed to be not harmful to the aquatic ecosystem.
... Further work has recommended a reduced in biodiversity close to ccA-treated marine structures, and examined the levels of metal elements in benthic organisms (Weis and Weis 1994a, b, 1995, 1996, Albuquerque and cragg 1995a, Wendt et al. 1996, cragg and Eaton, 1997, Weis et al. 1998. Although cu concentrations noticed that significantly elevated in algae growing on ccA-treated wood panels, increase in associated of fish species was found with the same panels (Weis and Weis 1999). This suggests that trophic transfer to consumers did not occur, although it was possible that the duration of the studies was insufficient to allow accumulation in higher consumers. ...
Preservation of wood is essential for the increase the life service of wood during the utilization. At the present time different type of chemical wood preservatives are used viz. copper sulfate, zinc chloride, mercuric chloride and oil born preservative (creosote) are used for the protect the wood from the different wood degrading agencies, but chemicals leach out from the wood and may negatively affect the environment, soil health, ecology and biodiversity. Due to the hazardous effect of chemical wood preservatives, it is essential need to replace with alternative eco-friendly wood preservative. Now chemical wood preservatives are replaced with the natural preservatives. Natural wood preservatives are consisting by resin, tannin and dye which are extract from the different parts of plants. Researchers conduct the research on the testing the efficiency of the natural preservatives against to the wood degrading agencies and find out the significant results. This review paper aims to compare the efficiency of bio preservatives with traditional available preservatives and promote the natural preservatives for the wood preservation.
... Although the arsenic, chromium and copper in CCA-treated wood are have low leachability over several decades, small amount of these toxic contaminants nonetheless do leach over time [10,11,12]. Preservative leaching from CCA-treated wood in the environment is an issue of concern with respect to both the wood product performance and possible impacts on human health and the environment [13,14,15]. ...
... They represent a good alternative especially in rocky shores where sediments are not easily found. Sessile and active filter feeding invertebrates are often used to determine temporal and spatial variation of TE in aquatic systems (Weis and Weis, 1999;Denton et al., 2006;Dahms et al., 2014). An ideal biomonitor should be a natural accumulator of the element of interest and possibly with high concentration factor, in order to highlight possible difference between times or sites (Rainbow, 2002). ...
... All the leachate solutions were diluted to provide a suitable copper concentration for Atomic Absorption analysis and determined copper in leachate and in blocks. Most of the wood preservatives' formulation contain copper because of its fungicidal characteristics and copper appears to be the primary cause of toxicity to aquatic organisms (Weis and Weis 1999, Brooks 2000, Breslin and Ivanbrook 1998. Therefore, the evaluate proportion of aquatic toxicity can be attributed to the leaching of copper as compared to the leaching of other chemicals found in treated wood ...
In this study, it was designed for determining leaching characteristics of CCA and alternatives wood preservatives. Alder wood blocks were treated with CCA (1 % and 2 %), ACQ-1900 (2 % and 3 %), ACQ-2200 (1 % and 2 %), Tanalith E 3491 (2 % and 2.8 %), Wolmanit CX-8 (% 1 and 2 %). Leaching studies were conducted according to AWPA E11-97. Copper analyses of leachate were determined Atomic absorption spectroscopy.
Results shows that alternative copper based wood preservatives were released higher copper amounts than CCA treated samples.
... Like terrestrial systems, the removal of habitat and the construction of new infrastructure are often ac-companied by unintentional, but potentially predictable, longer-term physical disturbances and ongoing input of contaminants ( Weis and Weis, 1999;Macreadie et al., 2011;Simpson et al., 2013). In areas of high density boating, such as marinas and ports, there is an increase in sediment metal concentration likely due to the leaching of anti-fouling coatings and paint flakes applied to vessel hulls ( McAllister et al., 1996;Turner, 2010;Rivero et al., 2013). ...
Infrastructure associated with coastal communities is likely to not only directly displace natural systems, but also leave environmental footprints' that stretch over multiple scales. Some coastal infrastructure will, there- fore, generate a hidden layer of habitat heterogeneity in sediment systems that is not immediately observable in classical impact assessment frameworks. We examine the hidden heterogeneity associated with one of the most ubiquitous coastal modifications; dense swing moorings fields. Using a model based geo-statistical framework we highlight the variation in sedimentology throughout mooring fields and reference locations. Moorings were correlated with patches of sediment with larger particle sizes, and associated metal(loid) concentrations in these patches were depressed. Our work highlights two important ideas i) mooring fields create a mosaic of habitat in which contamination decreases and grain sizes increase close to moorings, and ii) model- based frameworks provide an information rich, easy-to-interpret way to communicate complex analyses to stakeholders.
... Several regions with a long established CCA markets (eg. North America, Japan, Europe and Australasia, Indonesia, Japan, South Korea) have decidedly restricted the usage of CCA preservatives to non-residential environments or else have mandated the use of more organic preservative alternatives (Lebow 1996;Weis & Weis 1999;Brown & Eaton 2000;Hingston et al. 2001Hingston et al. , 2002Bhattacharya et al. 2002;Schultz & Nicholas 2002;Freeman et al. 2003;Stilwell et al. 2003). Many other CCAconsuming regions are considering similar restrictions or have taken greater precautions in CCA-treated wood usage. ...
... The form of chromium in the wood matrix is as Cr(III) [11], but combustion of CCA wood has been reported to result in oxidation of Cr(III) to Cr(VI) in some cases [10,14], a much more toxic form for humans [15]. Copper, too, is toxic to aquatic organisms [16] and can create problems, if copper containing wastes leach into sensitive aquatic ecosystems. ...
Chromated copper arsenate (CCA) was the dominant wood preservative used for outdoor wood products to prevent structural decay prior to its phase down starting from 2004. Incineration is one key disposal alternative for CCA-treated wood; however, it results in volatilization of metals at high temperature and accumulation of metals in ash. The objective of this study was to assess alkaline earth and iron based sorbents for their capability to minimize leaching of metals from the incinerator ash. Experiments were carried out by heating CCA metal spikes combined with sorbents to temperatures of 700, 900 and 1100 o C. The residual ash was analyzed for leaching retention using the toxicity characteristic leaching procedure (TCLP) and speciation by X-ray diffraction (XRD). Results show that alkaline earth sorbents (cement, calcium hydroxide and magnesium hydroxide) were the most promising for reducing the leaching of arsenic from the ash below the 5 mg/L TCLP limit and retaining copper at concentrations below detection limits. For chromium, iron and magnesium based sorbents resulted in the highest retention with low leachate concentrations (<5 mg/L) at 1100 o C. Leaching appeared to be highly pH dependent, with As and Cu leaching more at low pH values and Cr leaching more at high pH values. Results also indicate that the formation of compounds like Ca 3 As 2 O 7 , FeCr 2 O 4 and CuCr 2 O 4 during the reaction reduced the volatilization of metals. The results suggest that a combination of sorbents at different stages of high-temperature processes may offer effective control of the leaching of CCA metals.
... However, its excessive leaching can harm aquatic ecosystems and therefore warrants monitoring [20]. All the sorbents showed low leaching (< ~50 mg/L) for copper. ...
Past studies have shown that many alumino-silicate mineral sorbents are effective in controlling heavy metal emission during incineration. The objective of this study was to identify Al-Si based mineral sorbents that can minimize leaching of heavy metals from the incinerator ash of Chromated Copper Arsenate (CCA-) treated wood. Experiments were carried out using CCA metal spikes combined with Al-Si sorbents, heated to 700 oC, 900 oC and 1100 oC for 30 minutes. The residual ash was leached using the toxicity characteristic leaching procedure (TCLP). X-Ray Diffraction (XRD) analysis was conducted to determine the crystalline speciation of the products. Results showed that low leaching was observed for chromium, below the 5 mg/L TC limit, by alumina and silica at all temperatures, and kaolin at higher temperatures (900 oC and 1100 oC). For copper, all sorbents displayed low leaching values (< 51 mg/l) as compared to the baseline. For arsenic, all sorbents exceeded the TC limit. Speciation characterization results revealed the formation of several metal-metal and metal-mineral compounds that might have resulted in different leaching behaviors of each metal-sorbent pair under different combustion conditions. The results suggest that a combination of sorbents at different stages of the combustion process can be effective to control the leaching of CCA metals.
... Cr(VI) is much more toxic to humans than Cr(III) [27]; hence it should also be accounted for. Copper too, is toxic to aquatic organisms [28] and care should be taken while disposing copper containing wastes in sensitive aquatic ecosystems. Besides concerns over the potential toxicity of these wastes, another concern regarding burning them is the potentially lower heating value of CCA wood compared to regular wood, which may set a combustion facility's capacity limit. ...
Chromated Copper Arsenate (CCA) is a popular wood preservative applied to wood products to prevent environmental decay during outdoor use and hence has been predominant in the disposal sector in recent years. Estimates suggest that some CCA- treated wood waste in Florida is burned to produce energy. Incineration results in volatilization of metals during combustion and an accumulation and subsequent leaching of metals in the ash. This poses health and environmental concerns. Past studies have shown that many mineral sorbents are effective in controlling heavy metal volatilization in air phase during incineration. The objective of this study was to evaluate the viability of thermal processes in existing facilities as an option for the management of CCA wood waste in the state of Florida.
Three tasks were carried out to assess the use of existing wood-fired capable facilities as a viable option for the management of CCA wood waste. In the first task, an inventory of existing wood-fired capable facilities and their pollution control devices was compiled. This inventory included two categories: facilities using wood as their fuel and others (such as cement kilns, waste to energy (WTE) plants, coal fired boilers etc.) that can possibly be converted to burn wood. In Florida, amongst the facilities belonging to these categories, the maximum capacities corresponded to wood-based facilities, followed by WTE facilities and coal-fired plants with cement kiln boilers representing the smallest available capacity. While wood boilers also use a variety of carbonaceous fuels, cement kilns and coal fired plants primarily run on coal and use some secondary fuels as well. WTE facilities used municipal solid waste (MSW) for combustion. A variety of air pollution control devices are found in each facility depending on the types of air emissions at that facility. In terms of the maximum heat input rate/ heat capacity of the combustion boilers, coal fired power plants had the highest median heat capacity followed by cement kilns, wood boilers and WTE facilities.
In the second task, a literature survey was conducted on available pollution control technologies and equipment for controlling arsenic emission and leaching resulting from the incineration process. From the survey results, co-incineration appears to be the most promising technology amongst the existing techniques in the short term. Long term options for disposal of CCA treated wood by thermal processes need to be evaluated. Coupling co-incineration with sorbent injection in feed and gas stream can result in the dual benefit of controlling submicron particulate emissions as well as forming non-toxic, non leachable ash which can be disposed of easily. An evaluation of the existing options suggests that the use of a combination of air pollution control devices, e.g., using a wet scrubber combined with an ESP or a baghouse seems to be the best available technique to control arsenic emissions. Injection of mineral sorbents in the flue gas followed by capture of particulates using a baghouse or an ESP has been successful in controlling arsenic emissions in coal combustion and can be applied to wood waste too. Amongst the various techniques available for sampling of arsenic in ambient air, impregnated filters appear to have the highest particulate and vapor capture efficiency.
In the third task, potential mineral materials that can prevent arsenic leaching from incineration products were screened in laboratory studies. Experiments were conducted to evaluate various sorbent materials for their capability in reducing ash leachability as well as to characterize the crystalline speciation of the reaction products. Experiments were carried out using metal spikes with quantities equivalent to 3.68 pounds per cubic feet (pcf) of CCA-treated wood (treated with CCA type C chemical). The spike-sorbent samples were heated at 700 oC, 900 oC and 1100 oC for 30 minutes. A portion of the residual was leached using the toxicity characteristic leaching procedure (TCLP). X-Ray Diffraction (XRD) analysis of the residue was conducted to determine the crystalline speciation of the products. Amongst the various sorbents tested in the given temperature range, the alkaline earth sorbents (cement, calcium hydroxide and magnesium hydroxide) and ferric oxide (at 1100 oC) showed the greatest promise in reducing the leaching of arsenic to significantly lower values than the TC limit of arsenic from the incinerator ash. Regarding chromium, the alumino-silicate group (alumina and silica at all temperatures, and kaolin at higher temperatures), ferric oxide and magnesium hydroxide (at 1100 oC) leached less than the TC limit of chromium from the ash. For copper, all sorbents displayed low leaching values. Volatilization of metals was also reduced due to the metal-sorbent binding, up to 60% in some cases, depending on the type of sorbent used and the system temperature. Speciation characterization results reveal the formation of several metal-metal and metal-mineral compounds (e.g. insoluble Ca3(AsO4)2 and highly soluble CaCrO4). The formation of these compounds may have resulted in different leaching behavior of each metal-sorbent pair under different combustion conditions.
Potential practical scale applications of sorbent technology for thermal conversion of CCA treated wood have been proposed based on these results. At high temperatures (>1000 oC), most of the arsenic is found in the gas phase while chromium and copper remain in the feed. Hence, a strategy to control the leaching of metals can possibly be developed based on these studies. A single sorbent or a combination of sorbents can be used to effectively control the leaching of CCA metals, e.g., using cement in the flue gas to capture arsenic and any alumino-silicate sorbent or ferric oxide in the feed to capture chromium and copper. Another possible alternative could be using ferric oxide or magnesium hydroxide at high temperatures (~1100 oC) to capture all three CCA metal simultaneously, both in feed and gas phase. Based on this strategy, cement kilns, coal combustion plants, MSW incinerators and steel mills may be potentially viable options for disposal of CCA-treated wood by co-incineration.
... Thus, trophic transfer was seen only for the amphipods. Fish may have a more efficient mechanism for regulating metal levels in their tissues [20]. ...
Studies are reviewed that demonstrate the leaching of Cu, Cr, and As from pressure-treated wood in aquatic environments. The metals leached out accumulate in sediments near the wood (particularly bulkheads, which have more surface area for leaching than dock pilings). The metals also accumulate in organisms, including epibiota that live directly on the wood and benthic organisms, which live in sediments near the wood. Those inhabiting sediments closer to the wood accumulate higher levels of the contaminants. Other animals can acquire elevated levels of these metals indirectly as a result of consuming contaminated prey (trophic transfer). Once organisms have accumulated metals, they may exhibit toxic effects. Effects of CCA leachates in aquatic biota have been noted at the cellular level (e.g. micronuclei, indicating DNA damage), tissue level (e.g. pathology), individual organism level (e.g. reduced growth, altered behavior, and mortality), and community level (reduced number of individuals, reduced species richness, and reduced diversity). Effects are more severe in poorly flushed areas and in areas where the wood is relatively new. Residential canals lined with CCA wood are particularly toxic. The severity of effects is reduced after the wood has leached for a few months. Deleterious effects in the aquatic environment appear to be due largely to copper. Thus, alternative formulations
... Seawater testing may be indicative of material behavior when exposed to salt-laced snowmelt runoff. Testing of treated and untreated wood panels in freshwater showed that the metals leached from CCA-treated wood could be taken up by epibiota and trophically transferred (Weis and Weis 1999). Arsenault (1975 reported PCP around the base of, and in drainage ditches near, treated utility poles. ...
Development in sensitive watersheds continues to pose envi ronmental problems for receiving waters. One contributor to the long-term pollution of sens itive waterways is building and construction materials. However, the long-term effect of many building materials on the environment has not been quantified. Prior testing of these materials in the laboratory has indicated that the potential for release (primarily nutr ients, lighter hydrocarbons, pesticides, and metals) is significant. Additional testing for metals' release from aged roofing panels also has shown that the potential for pollutant release still ex ists after 60 years of exposure to the environment. The data that is missing from a complete evalua tion of specific building materials is behavior over the lifespan of the material, including the crit ical period of initial exposure. This paper provides an overview of the limited literature availa ble on the subject, results from laboratory testing of common building materials and aged roofi ng panels, and an overview of the next phase of needed research. Ongoing work at campuses in t wo rainfall/climate zones in the U.S. have been designed fill in the data gap.
... Most of the wood preservatives contain copper because of its fungicidal characteristics and copper appears to be the primary cause of toxicity to aquatic organisms [7][8][9]. Therefore, the evaluated proportion of aquatic toxicity can be attributed to the leaching of copper as compared to the leaching of other chemicals found in treated wood. ...
This study describes a laboratory method for the estimation of emission from preservative-treated wood in the different situations where emissions could enter the environment for use classes 3 (not in contact with ground) and 4 and 5 (in contact with the ground, fresh water or sea water) according to OECD Guidelines. Samples of scotch pine sapwood (Pinus sylvestris L.) were treated with CCA (1% and 2%), ACQ-1900 (3% and 7%), ACQ-2200 (2%), Tanalith E 3491 (2% and 2.8%), and Wolmanit CX-8 (2%).The results indicated that the lowest copper amounts were released from CCA-treated wood. Because of the higher copper amount in the leachates from the alternative wood preservatives, the emission rate of these leachates was higher than the leachates from CCA-treated wood.
... While the arsenic, chromium, and copper in CCA-treated wood are "fixed" such that the majority of preservative remains in the wood for several decades, small amounts of the metals nonetheless do leach over time [11][12][13][14][15][16]. Preservative leaching from CCA-treated wood in the environment is an issue of concern with respect to both the wood product performance and possible impacts on human health and the environment [10,[17][18][19]. ...
Leaching of arsenic, chromium, and copper from chromated copper arsenate (CCA)-treated wood poses possible environmental risk when disposed. Samples of un-weathered CCA-treated wood were tested using a variety of the US regulatory leaching procedures, including the toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), extraction procedure toxicity method (EPTOX), waste extraction test (WET), multiple extraction procedure (MEP), and modifications of these procedures which utilized actual MSW landfill leachates, a construction and demolition (C and D) debris leachate, and a concrete enhanced leachate. Additional experiments were conducted to assess factors affecting leaching, such as particle size, pH, and leaching contact time. Results from the regulatory leaching tests provided similar results with the exception of the WET, which extracted greater quantities of metals. Experiments conducted using actual MSW leachate, C and D debris leachate, and concrete enhanced leachate provided results that were within the same order of magnitude as results obtained from TCLP, SPLP, and EPTOX. Eleven of 13 samples of CCA-treated dimensional lumber exceeded the US EPA's toxicity characteristic (TC) threshold for arsenic (5 mg/L). If un-weathered arsenic-treated wood were not otherwise excluded from the definition of hazardous waste, it frequently would require management as such. When extracted with simulated rainwater (SPLP), 9 of the 13 samples leached arsenic at concentrations above 5 mg/L. Metal leachability tended to increase with decreasing particle size and at pH extremes. All three metals leached above the drinking water standards thus possibly posing a potential risk to groundwater. Arsenic is a major concern from a disposal point of view with respect to ground water quality.
... The toxicity of chromium and arsenate elements, which are released from chromated copper arsenate (CCA)-treated wood, against human health and the environment has generated a lot of controversy [1][2][3][4]. As a result, the use of CCA-treated wood for residential purposes was prohibited by the United States Environmental Protection Agency, but CCA is still extensively used to protect wood for outdoor uses [5]. ...
Okara, an organic waste product obtained from soy milk production, was used with copper chloride or sodium borate to formulate new wood preservatives as a substitute for expensive wood preservatives, such as copper-azole-based preservatives and ammoniacal copper quaternary. Before formulating the preservatives, okara was hydrolyzed by enzymes (cellulase, pectinase, and protease) to augment penetration and fix the biocide salts of the preservatives into wood blocks. The preservatives were injected into wood blocks by vacuum pressure to measure the treatability of the preservatives. The treated wood blocks were placed in hot water for 3 d to measure leachability. The treatability and leachability of the preservatives were affected by the type and loading amount of enzymes and the addition of sodium borate into okara-based wood preservative formulations. The treatability and leachability of the preservatives formulated with copper chloride and okara hydrolysates were 63.38 and 3.15%, and those of the preservatives with copper chloride, okara hydrolysates, and sodium borate were 61.47 and 3.32%, respectively. Despite the hot water leaching, wood blocks treated with preservatives formulated with 2% cellulase, pectinase, and protease hydrolyzed okara, CuCl(2), and sodium borate showed only 1.98% average weight loss against Fomitopsis palustris over 12 weeks. Microscopic observation revealed how okara-based preservatives work in wood blocks. Okara has potential as a raw material for cost-effective and environmentally friendly wood preservatives.
... The toxicity of chromium and arsenate elements, which are released from chromated copper arsenate (CCA)-treated wood, against human health and the environment has generated a lot of controversy1234. As a result, the use of CCA-treated wood for residential purposes was prohibited by the United States Environmental Protection Agency, but CCA is still extensively used to protect wood for outdoor uses [5]. ...
Novel biocides, such as copper azole (CuAz) and ammoniacal copper quaternary (ACQ), are extensively used as substitutes for chromate copper arsenate (CCA) in wood preservation. However, the expense of these biocides has necessitated the development of cost-effective and environmentally friendly wood preservatives. This study was conducted to investigate the effectiveness against decaying fungi of the preservatives formulated with enzymatic-hydrolyzed okara (OK), which is an organic waste produced from the manufacture of tofu, CuCl(2) (CC) and/or Na(2)B(4)O(7).10H(2)O (B). With the addition of NH(4)OH as a dissociating agent, the addition of OK facilitated the target retention of most of the OK/CC and OK/CC/B preservative formulations in wood blocks. The OK-based wood preservatives (OK-WPs) were stable against hot-water leaching. When compared with control and CC-treated wood blocks, the leached wood blocks treated with OK/CC and OK/CC/B formulations showed excellent decay resistance against both Postia placenta and Gloeophyllum trabeum, especially when OK was hydrolyzed by Celluclast at a loading level of 0.1 ml/g. Scanning electron microscopy (SEM) and SEM-energy dispersive X-ray (SEM-EDX) spectrometry analyses demonstrated that preservative complexes, such as OK-CC and OK-CC-B, existed in the wood blocks treated with OK/CC and OK/CC/B formulations. This study results support the potential application of OK-WPs as environmentally friendly wood preservatives capable of replacing CuAz and ACQ.
... Concerns about the safety and environmental impact of wood preservatives have increased in recent years. Arsenic and chromium are considered human carcinogens and Cu can be toxic to aquatic organisms (Flemming and Trevors, 1989;Weis and Weis, 1999;Dubey et al., 2007). Metals release from treated wood has been reported by many researchers during the wood service life (Khan et al., 2006a;Shibata et al., 2007), during disposal (Khan et al., 2006b;Jambeck et al., 2006;Moghaddam and Mulligan, 2007) and from recycled forms such as mulch (Jacobi et al., 2007;Shibata et al., 2006). ...
Earlier studies documented the loss of wood preservatives from new wood. The objective of this study was to evaluate losses from weathered treated wood under field conditions by collecting rainfall leachate from 5 different wood types, all with a surface area of 0.21 m(2). Wood samples included weathered chromate copper arsenate (CCA) treated wood at low (2.7 kg/m(3)), medium (4.8 kg/m(3)) and high (35.4 kg/m(3)) retention levels, new alkaline copper quat (ACQ) treated wood (1.1 kg/m(3) as CuO) and new untreated wood. Arsenic was found to leach at a higher rate (100 mg in 1 year for low retention) than chromium and copper (<40 mg) in all CCA-treated wood samples. Copper leached at the highest rate from the ACQ sample (670 mg). Overall results suggest that metals' leaching is a continuous process driven by rainfall, and that the mechanism of release from the wood matrix changes as wood weathers.
... In spite of highly elevated concentrations of sediment-associated Cu (up to 1400 lg g À1 dry weight) as well as their potential dietary sources of Cu (up to 200 lg g À1 dry weight in Palaemonetes pugio), mummichogs accumulated a relatively low amount of Cu ($10 lg g À1 dry weight). Weis and Weis (1999) have also demonstrated in a three-month field transplant experiment that mummichogs accumulated much less Cu than crustaceans such as P. pugio. Furthermore, there was no difference in Cu intracellular partitioning among the populations in the current study; mummichogs generally partitioned more Cu as BDM (24–34%) than MSF (19–27%). Unli ...
Intracellular partitioning of trace metals is critical to metal detoxification in aquatic organisms. In the present study, we assessed metal (Cd, Cu, Pb, and Zn) handling capacities of mummichogs (Fundulus heteroclitus) in metal-polluted salt marshes in New York, USA by examining metal intracellular partitioning. Despite the lack of differences in the whole body burdens, partitioning patterns of metals in intracellular components (heat-stable proteins, heat-denaturable proteins, organelles, and metal-rich granules) revealed clear differential metal handling capacities among the populations of mummichogs. In general, mummichogs living in metal-polluted sites stored a large amount of metals in detoxifying cellular components, particularly metal-rich granules (MRG). Moreover, only metals associated with MRG were consistently correlated with variations in the whole body burdens. These findings suggest that metal detoxification through intracellular partitioning, particularly the sequestration to MRG, may have important implications for metal tolerance of mummichogs living in chronically metal-polluted habitats.
... In spite of a highly elevated trophic availability (i.e., TAM-[Cu]) from P. pugio, the majority of ingested Cu may have been efficiently eliminated from mummichogs. Weis and Weis (1999) have demonstrated in a field transplant experiment that, compared to crustaceans such as P. pugio, mummichogs accumulated substantially lower Cu after three months. In contrast, both the AK and reference populations of mummichogs accumulated a substantial amount of Zn. ...
Intracellular partitioning of trace metals is critical to metal tolerance in aquatic organisms and may also influence metal trophic transfer in ecosystems. In this study, we tested the relevance of metal (Cd, Cu, Pb, and Zn) intracellular partitioning in prey as an indicator of metal trophic availability to benthic forage fish, mummichogs (Fundulus heteroclitus), in chronically metal-polluted salt marshes in New York, USA. Two common prey of mummichogs in the study area, Palaemonetes pugio and Nereis acuminata, generally stored increasingly higher proportions of non-essential metals (particularly Pb) in insoluble (less trophically available) cellular components, as the whole body burdens increased. In contrast, intracellular partitioning of essential metals (Cu and Zn) in invertebrate prey varied relatively little among sites. Differential Cd and Pb intracellular partitioning patterns within P. pugio among sites were significantly associated with Cd and Pb whole body burdens in mummichogs, respectively (i.e., prey-driven bioreduction of metals), while bioaccumulation of Cu and Zn in mummichogs was similar among populations. The findings in this study suggest that metal intracellular partitioning within prey may be partially responsible for metal trophic availability to a predator in metal-polluted habitats, while there was also evidence that some predator-dependent processes may offset differential trophic availabilities from prey.
... Further work has suggested a decrease in biodiversity close to CCA-treated marine structures, and elevated levels of metal elements in benthic organisms (Weis and Weis, 1994a, b, 1995Albuquerque and Cragg, 1995a;Wendt et al., 1996;Cragg and Eaton, 1997;Weis et al., 1998). Although Cu concentrations were found to be signi®cantly elevated in algae growing on CCA-treated wood panels, no increase was found in ®sh species associated with the same panels (Weis and Weis, 1999). This suggests that trophic transfer to consumers did not occur, although it was possible that the duration of the studies was insucient to allow accumulation in higher consumers. ...
Recent studies have generated conflicting data regarding the bioaccumulation and toxicity of leachates from preservative-treated wood. Due to the scale of the wood preserving industry, timber treated with the most common preservative, chromated copper arsenate (CCA), may form a significant source of metals in the aquatic environment. The existing literature on leaching of CCA is reviewed, and the numerous factors affecting leaching rates, including pH, salinity, treatment and leaching test protocols are discussed. It is concluded from the literature that insufficient data exists regarding these effects to allow accurate quantification of leaching rates, and also highlights the need for standardised leaching protocols.
... The most common wood preservative used in recent years has been chromated copper arsenate (CCA) (AWPA, 1999;Solo-Gabriele et al., 1998). CCA contains chromium, copper and arsenic, and all three heavy metals have potential adverse impacts on human health and the environment (Weis et al., 1995;Weis and Weis, 1999;Brown et al., 2001;Decker et al., 2002;Gordon et al., 2002). Arsenic and chromium are regulated in the US as primary drinking water standards (50 and 100 mgyl, respectively) while copper is regulated as a secondary drinking water standard (1000 mgyl). ...
The production of landscape mulch is a major market for the recycling of yard trash and waste wood. When wood recovered from construction and demolition (C&D) debris is used as mulch, it sometimes contains chromated copper arsenate (CCA)-treated wood. The presence of CCA-treated wood may cause some potential environmental problems as a result of the chromium, copper, and arsenic present. Research was performed to examine the leachability of the three metals from a variety of processed wood mixtures in Florida. The mixtures tested included mixed wood from C&D debris recycling facilities and mulch purchased from retail outlets. The synthetic precipitation leaching procedure (SPLP) was performed to examine the leaching of chromium, copper and arsenic. Results were compared to Florida's groundwater cleanup target levels (GWCTLs). Eighteen of the 22 samples collected from C&D debris processing facilities leached arsenic at concentrations greater than Florida's GWCTL of 50 microg/l. The mean leachable arsenic concentration for the C&D debris samples was 153 microg/l with a maximum of 558 microg/l. One of the colored mulch samples purchased from a retail outlet leached arsenic above 50 microg/l, while purchased mulch samples derived from virgin materials did not leach detectable arsenic (<5 microg/l). A mass balance approach was used to compute the potential metal concentrations (mg/kg) that would result from CCA-treated wood being present in wood mulch. Less than 0.1% CCA-treated wood would cause a mulch to exceed Florida's residential clean soil guideline for arsenic (0.8 mg/kg).
... In 1996, CCA-preserved wood represented 79% of the U.S. wood preservative market (2). Environmental and health issues stemming from the chemicals in CCA-treated wood, primarily arsenic, have raised concerns over its use and disposal (3)(4)(5)(6)(7). The wood preservation industry and the U.S. Environmental Protection Agency (EPA) agreed to phase out the production of CCAtreated wood for many uses (predominantly residential) beginning in January 2004. ...
Size-reduced samples of southern yellow pine dimensional lumber, each treated with one of five different waterborne chemical preservatives, were leached using 18-h batch leaching tests. The wood preservatives included chromated copper arsenate (CCA), alkaline copper quaternary, copper boron azole, copper citrate, and copper dimethyldithiocarbamate. An unpreserved wood sample was tested as well. The batch leaching tests followed methodology prescribed in the U.S. Environmental Protection Agency toxicity characteristic leaching procedure (TCLP). The wood samples were first size-reduced and then leached using four different leaching solutions (synthetic landfill leachate, synthetic rainwater, deionized water, and synthetic seawater). CCA-treated wood leached greater concentrations of arsenic and copper relative to chromium, with copper leaching more with the TCLP and synthetic seawater. Copper leached at greater concentrations from the arsenic-free preservatives relative to CCA. Arsenic leached from CCA-treated wood at concentrations above the U.S. federal toxicity characteristic limit (5 mg/L). All of the arsenic-free alternatives displayed a greater degree of aquatic toxicity compared to CCA. Invertebrate and algal assays were more sensitive than Microtox. Examination of the relative leaching of the preservative compounds indicated that the arsenic-free preservatives were advantageous over CCA with respect to waste disposal and soil contamination issues but potentially posed a greater risk to aquatic ecosystems.
Hazardous waste in the environment is one of the most difficult challenges facing our society. The purpose of this book is to provide a background of the many aspects of hazardous waste, from its sources to its consequences, focusing on the risks posed to human health and the environment. It explains the legislation and regulations surrounding hazardous waste -- however, the scope of the book is much broader, discussing agents that are released into the environment that might not be classified as Hazardous Waste under the regulatory system, but nonetheless pose substantial hazards to human health and the environment. It provides a background of some of the major generators of hazardous wastes, explains the pathways by which humans and wildlife are exposed, and includes discussion of the adverse health effects linked to these pollutants. It provides numerous case studies of hazardous waste mismanagement that have led to disastrous consequences. And highlights the deficiencies in science and regulation that have allowed the public to be subjected to a myriad of potentially hazardous agents. Finally, it provides a discussion of measures that will necessarily need to be taken to control society's hazardous waste problem. This book was designed to appeal to a wide range of audiences, including students, professionals, and general readers interested in the topic. Provides information about sources of and health risks posed by hazardous wasteExplains the legislation and regulations surrounding hazardous wasteIncludes numerous case studies of mismanagement, highlights deficiencies in science and regulation and discusses measures to tackle society's hazardous waste problems.
The importance of a circular economy is today widely accepted and advocated, but among the challenges in achieving this, we find difficulties in the implementation of legislation and policies designed to control various waste streams from society. The example used in this article is wood that has been treated with chromated copper arsenate (CCA), which, in Sweden, has been covered by the rules for hazardous waste since 2002. One year later, in 2003, a survey showed that only 42% to 50% of the expected amount of CCA waste could be traced to the public waste management system. An updated material flow analysis for 2010 revealed that the figure had increased to 73%, whereas the fraction of correctly treated CCA wood waste had increased from 11% to 35%. However, almost one third of the expected volume was still not tracable, and half of the amount that was correctly submitted was incinerated together with nontoxic waste fractions. This results in, for example, arsenic contamination of slag and fly ashes that prevents the further use of these residue products. So, despite legislative instruments, there is still an urgent need for an improved collection of hazardous wood waste, as well as better routines for identifying hazardous flows and separating them from nonhazardous ones. For a circular economy to be achievable, a key priority should be to reduce the gap between intended directions and legislation, on one hand, and activities in practice on the other.
This study investigated the use of TGA under different thermal decomposition conditions (nitrogen or air, and 5 or 40°C/min) to evaluate preservative-treated woods and their preservatives. It also analyzed the residual elements in the char using EDX. Two types of preservative-treated woods were investigated. One impregnated with CCA-3 and the other one treated with ACQ-1 using a full-cell treatment. The results of the TGA showed that the thermal properties of CCA- or ACQ-treated wood were similar to that of untreated wood in either a nitrogen or an air atmosphere, but the pyrolysis temperature for the heating rate of 5°C/min was lower than that of 40°C/min. Regardless of different atmosphere or heating rate, the char of the CCA specimens and the CCA-3 was more than that of the ACQ ones and the ACQ-1. The results of the EDX analysis of both preservative-treated woods show that the main element is C (CCA: 47.96%; ACQ: 50.24%), and that the relative proportion of C (CCA: 60.42%; ACQ: 77.89%) is higher after thermal decomposition. Cr from the char of CCA-3 is a stable element, and the amount of Cr (34.99%) is obviously more than that of As (11.89%) and Cu (16.69%). The char of ACQ-1 left a high amount of inorganic metal elements, such as Cu (50.14%). This suggests that by using EDX to analyze the residual elements in char, the results can provide experimental data for referencing the disposal-end practices (char) of both preservative-treated woods.
This study used Taiwania cryptomerioides Hay as a specimen to be treated with CCA-3 or ACQ-1 preservatives. CCA and ACQ-treated woods, the preservatives themselves as well as their individual ingredients during combustion were investigated. The emission gas concentrations of O 2 and CO 2, the emission contents (CO, SO 2, NOx), and the temperature of the emission gases were measured using a Flue-gas Analyzer at the exit of a 45° flammability testing cabinet as specified in the continuous emission monitoring (CEM) techniques. The specimens were analyzed with an Energy Dispersive X-ray Spectrometer (EDX), and were examined in a 45° flammability testing cabinet before and after the analysis. The residual elements in the char were also analyzed using an Elemental Analyzer (EA). The results indicated that the emission gas temperatures of all samples rose rapidly to about 200-250°C and then slowed down to a temperature range of 200°C, shown as a plateau curve. The concentration of O 2 decreased from 20.7% to about 17.0-19.8% linearly, and contrary to the concentration of CO 2 increased from 0.2% to about 1.8-2.8%. Both O 2 and CO 2 then approached the shape of a plateau curve until the end of the combustion time, and were closely related during the combustion. The highest emission quantity of CO was about 179.3 ppm for the ACQ specimen, 157.0 ppm for As 2O 5, and about 85.5ppm for BKC. The emission quantity of SO 2 for each type of sample was zero. The maximum NOx for the ACQ specimens and ACQ-1 preservatives were about 23.5-26.5 ppm, and about 32.0 ppm for BKC. The result of the EDX analysis indicated that the main element is C (77.89%), and that the relative proportion of Cu was 2.67% for the ACQ specimen, but that ACQ-1 was left with a high amount of Cu, of 50.14%. The result of the EA analysis inferred that the ACQ specimen could produce NOx gases during combustion, because the amount of N (1.42%) was higher for ACQ-1 than for the other specimens, and the BKC was almost burned out.
Chromated copper arsenate (CCA) is a chemical mixture consisting of three pesticide compounds (chromium, copper and arsenic) registered as wood preservatives to prevent fungal or microbial decay. CCA is injected into wood by a process that uses high pressure to saturate wood products with the chemical. CCA-treated wood is commonly used for telephone poles, fence posts, playground equipment, decks, walkways, boat docks and home constructions like fences or pool floors. In this study, a review of the literature was performed, involving articles relating to the toxicology of CCA, a preservative which is responsible for the largest volume of treated wood in the world. This included relevant information concerning occupational aspects and public health, particularly its use in homes, parks and playgrounds and aquatic environments to which the public has access. More attention was given to arsenic, as compared to chromium and copper, because it is the most toxic component in the formula, since it has greater leaching properties, from wood treated with CCA, as compared to chromium, the second most toxic component. For Brazil BIREME- Latin American and Caribbean Center for Information in Health Sciences was consulted. This gathers 114 Brazilian scientific publications. International literature was researched using Pub Med, a service of the American National Library, which includes MEDLINE. The Periodicals Portal of CAPES was also accessed for international publications, as well as the National system of Toxic-Pharmacological Information - SINITOX.
Three types of wood preservatives, creosote oil (Creosote), chromated copper arsenate (CCA-3) and ammoniacal copper quats (ACQ-1) were studied, first by using thermogravimetric analysis (TGA) under different heating rates (5 or 40°C/min), and then by using thermogravimetric analysis with infrared spectrometry (TGA-IR) and energy dispersive X-ray spectrometry (EDX). The results obtained from the TGA tests found that the decomposition temperature of each of the preservatives for the heating rate at 5°C/min was lower than that at 40°C/min. Regardless of different heating rate, the char (wt %) of the CCA-3 was more than that of the ACQ-1, and the amount of char for the Creosote was tower than that for either of the water-based preservatives. The IR response of all preservatives in the TGA-IR tests showed that at a heating rate of 5°C/min, the absorbance of Creosote and ACQ-1 was higher than that of CCA-3. This indicated that the concentration of evolved species of CCA-3 was less than that of Creosote and ACQ-1. However, at a heating rate of 40°C/min, the absorbance of CCA-3 and ACQ-1 was higher than that of Creosote. Considering the decomposition step (thermal time or temperature) at different heating rates in the TGA tests and the IR response from the TGA-IR analysis, the results obtained showed that at the slow-heating regime, the concentrations of CO2 produced by Creosote and ACQ-1 were higher than that of CCA-3, but at the fast-heating regime, the concentration of CO 2 for ACQ-1 was higher than that of Creosote and CCA-3. The EDX analysis of all preservatives showed that the main element of the char for Creosote was C (82.75%) after combustion. The char of CCA-3 had an amount of Cr (34.99%) that was obviously more than that of As (11.89%) and Cu (16.69%) due to Cr being a stable element during combustion. The char of ACQ-1 left a high amount of inorganic metal elements, such as Cu (50.14%). These results, when compared to the chemical ingredients of all preservatives, enabled us to point out the kinds of evolved species for referencing the thermo-decomposition processes of the preservatives. The use of TGA for analyzing the thermal properties of three types of preservatives, in combination with TGA-IR and EDX analysis, has led to useful results, regarding the identification of thermal decomposition products (evolved species and char).
The objective of this research was to evaluate the effects of waterborne preservative-treated wood on the performance of fungal decay resistance, termite resistance, and thermal properties. Preservatives, including chromated copper arsenate (CCA), ammoniacal copper quats (ACQ), tanalith CY (TCY), and ammoniacal copper azole (CuAz) were applied. Tested specimens were respectively impregnated with a preservative solution at 1.25, 2.5, and 5.0% w/w for CCA, and at 2, 4, and 6% w/w for ACQ, TCY, and CuAz using a full-cell process under pressure treatment. Fungal decay resistance, termite resistance, and the thermal properties of the treated wood were evaluated according to ASTM standard D1413-76 (1999), AWPA E1-97 (1999), and a thermogravimetric analysis. Results revealed that wood treated with ACQ, TCY, or CuAz was effective in resisting attack by 3 brown rot fungi (Fomitopsis pinicola, Laetiporus sulphureus, and Gloeophyllum trabeum), white rot fungus (Trametes versicolor), and termites (Coptotermes formosanus). Similar results were also found for CCA-treated wood. Weight losses of 2% ACQ-, TCY-, and CuAz-treated wood blocks were less than 2% after inoculation with brown rot and white rot fungi for 12 wk, indicating that such treatments resulted in good effectiveness against fungi deterioration. After 4 wk of feeding, the mortality of termites was 100% using 2% ACQ-, TCY-, and CuAz- treated blocks, indicating that such treatments resulted in good effectiveness against termite attack. Moreover, char yields of treated wood were significantly improved at higher concentrations of preservative treatment in a nitrogen atmosphere with the thermogravimetric analysis (TGA). However, differences in thermal properties were observed among all treatments in an air atmosphere with the TGA.
Development in sensitive watersheds continues to pose environmental problems for receiving waters. Materials, such as galvanized metal, concrete, asphalt and wood products, may release pollutants into urban runoff and snowmelt; however, the long term effect of commonly-used roofing materials on the environment has not been quantified. This lack of long-term testing poses a particular problem because roofing is ubiquitous in the urban environment and covers a comparatively large amount of the surface area available to generate runoff. Laboratory testing on common roofing materials indicated that the potential for release (primarily nutrients, hydrocarbons, pesticides, and metals) is substantial. Further testing on painted, galvanized roofing tiles that were exposed to the Pennsylvania climate for 60+ years indicated that material continued to be released from these panels - indicating a deeper reservoir than simply the loss of a sacrificial surface coating. The ongoing research project involves testing a variety of construction materials (roofing materials, treated and untreated woods) to determine their long-term pollutant release after typical installation and exposure to the weather. The goal is to develop a better understanding of how the aging and exposure processes will impact the release over time. Understanding the 'release vs. time' of a pollutant from a material will be crucial for translating the laboratory results to the actual environment and to developing predictive models for evaluating new materials for their pollutant potential. To accomplish this, at PSH and UAB, intact sections of these materials were installed on outdoor frames in areas not subject to canopy cover. Initial testing showed that nutrient concentrations were elevated early in the materials' life, as were the metals. Now, over one year of installation and testing has occurred. For many of the pollutants, the concentrations have leveled off to much lower concentrations. For most pollutants, especially nutrients, periodic spikes in runoff concentrations can be correlated to noticeable degradation in the material itself. Preliminary metals results show that lead concentrations are just above the detection limit, while copper releases are much greater for many materials. Runoff concentrations of copper for asphalt shingles and the two treated wood panels exceeded 500 μg/L during the first two weeks of exposure (with multiple storms during that period to wash off any surface coating).
The upstate and Piedmont region of South Carolina is a rapidly urbanizing area as a result of a steadily growing population. This increase in population and development has the potential to negatively impact local aquatic systems like the Saluda River due to increased pollution from runoff, and effluents from industrial and wastewater treatment facilities. During the summer months of 2010, 159 fish from the Centrarchidae family (sunfish species (Lepomis) and largemouth bass - Micropterus salmoides) were collected from 13 sites along the Saluda River. A suite of biomarker assays, including ethoxyresosufin-O-deethylase, bile fluorescence, glutathione S-transferase, thiobarbituric acid reactive substances, bile estrogens, acetylcholinesterase inhibition, metallothionein and tissue metal levels were applied to investigate the impacts of diminished water quality on fish health. Results indicate that fish from the Saluda River are responding to contamination in a site specific manner, with up to four significant biomarker responses in the most impacted sites. Sampling sites in the lower portion of the Saluda watershed are less impacted by pollution than the upper and central sections. The observed biomarker responses can be explained by the proximity of urban areas, point sources and general land use, and demonstrate the applicability of biomarkers in environmental biomonitoring programs.
Despite considerable improvements in water quality over the last few decades, the ecological integrity of benthic habitats in the Arthur Kill (AK), New York, USA, largely remains altered. This dissertation explores how altered ecological status of benthic habitats directly and indirectly (via food webs) affected a resident forage fish, mummichogs (Fundulus heteroclitus ), in highly urbanized tidal salt marshes in AK. A substantial portion of total abundance and biomass of benthic macroinvertebrates (a primary prey resource for mummichogs) in AK were comprised of only a few opportunistic oligochaete and polychaete species. And these alterations in benthic macroinfaunal communities in AK were strongly associated with the sediment-associated mercury level. Alterations in the AK benthic macroinfaunal assemblages were generally reflected in diet habits and strategies of mummichogs; a generalized feeding strategy with a broad diet niche breadth of mummichogs shifted to more specialized strategies for many of the AK populations. Although decapods (especially Palaemonetes spp.) were the predominant prey for all populations of mummichogs, the length-specific maximum sizes of Palaemonetes spp. ingested by some of the AK populations of mummichogs were about 2-fold smaller than those ingested by the reference population. These shifts in feeding habits were compensated for with an increased consumption of polychaetes by most of the AK populations and polychaetes contributed up to more than 40% of their gut contents. Partial trophic decoupling between mummichogs and dominant benthic macroinvertebrates had further implications for biogeochemical cycling of trace metals and energy transfer in AK. Alterations in benthic macroinfaunal prey communities reduced trophic transfer efficiency (i.e., exposure levels) of metals to mummichogs. Furthermore, despite their compensatory food consumption, most of the AK populations of mummichogs had considerably elevated total metabolism, resulting in substantially reduced growth conversion efficiency. This reduction in energy conversion efficiency at the individual level can cascade through trophic chains, potentially leading to energetic bottlenecks at the community level. Altered salt marsh trophic structures in AK and their resultant impacts on mummichog (a crucial trophic link in urban estuaries) bioenergetics may thus disrupt energy translocation in this severely degraded coastal ecosystem.
There exists a possibility of leaching out of chemicals along with preservative components from chemically treated wood on exposure to water or moisture. Physical barriers have gained much acceptance in this regard as alternative non-biocidal wood protection method as it is supposed to reduce leaching and subsequent negative impacts of wood preservative components to the organisms in vicinity. Fibreglass reinforced plastic (FRP) and epoxy paint was coated over chromated copper arsenate (CCA) treated rubber wood panels and exposed in Cochin estuary for 18 months. Total wet weight biomass and numerical abundance of five most abundant group of foulers viz. hydroids, polychaetes, crustaceans including wood borers, barnacles and bivalves on these panels were studied. Copper, chromium and arsenic concentration in tissues and shells of barnacles were also analyzed. Results indicated significantly high biomass and numerical abundance of foulers on physically protected panels than untreated and preservative treated ones. Physical barriers significantly reduced accumulation of metals in barnacles indicating possibility of reduced leaching. Study can be considered as a lean to the impact studies conducted world over regarding the use of CCA for marine applications. However, CCA treated rubber wood as core material for FRP boats can be a better option as it poses less adverse effect on organisms in the vicinity.
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.
In this work we studied the trophodynamics of five potentially toxic trace elements, chromium (Cr), cobalt (Co), silver (Ag), arsenic (As) and selenium (Se), in the biota of 3 lakes belonging to Nahuel Huapi and Los Alerces National Parks (NHNP and LNP respectively), as well as some aspects of the toxicological risk for humans and biota. From the trace elements quoted above, Ag, Cr, and Co were associated in previous work with anthropogenic contamination, with concentrations of Ag in fish livers among the highest reported globally.
This study was focused at 2 levels, a) the whole biota of Lake Moreno (NHNP) and b) the top predator fish from the same lake and from Lakes Futalaufquen (LNP) and Nahuel Huapi (NHNP). Samples from plankton, benthos and nekton communities were taken between 2004 and 2009 through conventional methods. Elements concentrations were measured by using Instrumental Neutron Activation Analysis in Centro Atómico Bariloche. The trophodynamics of elements was studied through the C and N stable isotopes ratios technique, en “Queen´s Facility for Isotope Research, at The Stable Isotope and ICP/MS Laboratory at Queen‟s University, Canada.
Concerning the trophodynamics of Ag, As and Co, the C source (benthic- littoral or pelagic) analysis in the diet of organisms from Lake Moreno, showed no differences between its 2 basins. On the opposite, between-basins differences arose concerning Cr and probably Se. Based on supporting evidence, the present work hypothesizes, for the first time, that the morphology of a lake (lake Moreno) influences the trophodynamics of Cr, and probably Se.
In the biota of Lake Moreno, a general pattern of biodilution of Ag was observed between primary producers and the forage fish G. maculatus when whole body [Ag] was analyzed. Nevertheless when considering the whole food web trend, and hepatic [Ag] of top predator fish, a biomagnification pattern was observed. The present work evaluates the trophodynamics and reports tissue-specific biomagnification of Ag in a whole fresh water ecosystem for the first time.
Chromium, Co and As showed biodilution patterns in the 2 basins of Lake Moreno whereas Se did not present any pattern. Furthermore, fish from the western basin had higher [Cr] that those from the eastern one, probably due to a higher proportion of benthic-littoral preys in their diets.
Some trophodynamic trends observed in the whole food web of Lake Moreno were reflected in top predator fish from the same lake and from the lakes Futalaufquen and Nahuel Huapi considered together. Both in the whole biota from Lake Moreno, and in top predator fish from the 3 lakes, the C source was important for Cr trophodynamics but not for Co, As and Ag. On the opposite, the biodilution pattern observed in the whole food web of Lake Moreno for Co and As, was not reflected in top predator fish from the 3 lakes.
Relative to risk, trace element concentrations measured in muscle tissue of top predator fish from different lakes (exposure source for humans) enable us to state that, with the possible exceptions of Cr (minimal risk levels are not set for total Cr) and chronic exposures to As, there is no risk evidence for human health. In the case of Ag,
VI
experimental studies including fish eating vertebrates like the Kelp Gull and the endangered Southern River Otter, could be of interest.
As a substitute for high-cost copper azole (CuAz) and alkaline copper quaternary (ACQ) wood preservatives, alternative wood
preservatives were formulated with okara, which is an organic waste from the production of tofu, and copper chloride and/or
borax. Each preservative was used in treatment of wood blocks in a reduced-pressure method to measure its treatability. The
treated wood blocks were placed in hot water for 3 days to examine the stability of the preservatives against hot-water leaching.
The preservatives successfully penetrated into wood blocks, probably due to the use of ammonium hydroxide as a dissociating
agent. However, the stability of okara-based preservatives dropped as the concentration of acid in the solutions used for
hydrolysis of okara increased. The treatability and leachability of the preservatives were not affected by hydrolysis temperature
but were negatively affected by the addition of borax. Leached wood blocks treated with okara-based preservatives and exposed
to decay fungi Gloeophyllum trabeum and Postia placenta over 12 weeks showed good decay resistance. Okara-based wood preservatives can protect wood against fungal attack as effectively
as CuAz, and have potential for use as environmentally friendly wood preservatives.
The disaster debris from Hurricane Katrina is one of the largest in terms of volume and economic loss in American history. One of the major components of the demolition debris is wood waste of which a significant proportion is treated with preservatives, including preservatives containing arsenic. As a result of the large scale destruction of treated wood structures such as electrical poles, fences, decks, and homes a considerable amount of treated wood and consequently arsenic will be disposed as disaster debris. In this study an effort was made to estimate the quantity of arsenic disposed through demolition debris generated in the Louisiana and Mississippi area through Hurricane Katrina. Of the 72 million cubic meters of disaster debris generated, roughly 12 million cubic meters were in the form of construction and demolition wood resulting in an estimated 1740 metric tons of arsenic disposed. Management of disaster debris should consider the relatively large quantities of arsenic associated with pressure-treated wood.
The potential environmental impacts from the use of treated timber in aquatic areas is under scrutiny as a result of environmental legislation and reports of the deleterious environmental effects around treated structures. In this study leaching experiments of up to 3 weeks duration were conducted on two species of chromated copper arsenate treated timber, dried for different periods of time. Increased drying time significantly reduced leaching of Cr and As. The addition of a synthetic humic acid increased leaching of Cu and As, but reduced leaching of Cr. Putative risk assessments conducted using short-term copper leaching data suggested protocol design may influence decisions made regarding the environmental acceptability of such preservatives.
Tidal creeks and their associated salt marshes are the primary link between uplands and estuaries in the southeastern region. They are also critical nursery and feeding grounds. In addition, the uplands surrounding creeks are preferred sites for homebuilding because of their natural beauty and the ability to access the estuary from a personal dock structure. The objective of this study was to evaluate the cumulative impacts of docks on tidal creek nursery habitats for both small and large tidal creeks. The number of docks was associated with the amount of impervious cover in both small and large creeks. The presence of docks had little measurable effect on sediment metal concentrations at the scale of small and large creeks. In small and large creeks, sediment polycyclic aromatic hydrocarbon (PAH) concentrations were related to the human activity in the upland that includes the presence of docks at the scale of small and large creeks. Some impacts on the benthic community were associated with docks and human activity in small creeks but not in large creeks. Suburban development may reduce fish and crustacean abundances, but the dock may potentially mediate the development effect. Individually, the harm to the marine environment resulting from dock shading, chrominated copper arsenate leachates, and PAH contamination was small at the scale of tidal creeks. However, impacts from dock structures could not be separated from anthropogenic watershed-scale effects. These results demonstrate that suburban development with its accompanying dock construction does represent a major source of environmental degradation to tidal creeks and associated salt marsh habitats.
Disposal of discarded chromated copper arsenate (CCA)-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteristic (TC) limit of 5mg/L in most cases. The majority of discarded CCA-treated wood, however, results from demolition activities, where the wood has typically been subjected to weathering. Since preservatives do migrate from the wood during its normal use, leaching characteristics of weathered and aged CCA-treated wood may differ from unweathered wood. To evaluate this, CCA-treated wood removed from service after various degrees of weathering was collected from multiple sources and leached with the TCLP, the synthetic precipitation leaching procedure (SPLP) and California's waste extraction test (WET). Five to seven individual pieces of wood were analyzed from each source. The average TCLP arsenic concentration for the 14 sources ranged from 3.2 to 13 mg/L. The average TCLP concentrations of the 100 wood pieces tested were 6.4, 5.9 and 3.2 mg/L for arsenic, copper and chromium, respectively. Overall, in 60 out of 100 samples tested by the TCLP, arsenic concentrations exceeded 5 mg/L (the TC regulatory value). SPLP leachate concentrations were similar to TCLP concentrations, although copper leached somewhat more with the TCLP. WET leachate concentrations were approximately a factor of 10 higher than TCLP concentrations. Discarded CCA-treated wood, even after exposure to years of weathering, often exceeds the TC limit for arsenic and without the current regulatory exemption would possibly require management as a TC hazardous waste in the US.
Chromated copper arsenate (CCA) is currently the most commonly used wood preservative in Korea. Questions, however, have been raised regarding the potential environmental impacts of metal leaching from CCA-treated wood to soil. Although a number of researchers from other countries have reported that chromium, copper, and arsenic do leach from CCA-treated wood over time, to date few field studies have been performed on those metals in soils adjacent to CCA-treated wood structures in Korea. The present study was conducted to determine the lateral and vertical distributions and accumulation of chromium, copper, and arsenic in soils collected from CCA-treated wood structures. A total of fifty-five composite soil samples were collected from four CCA-treated wood structures of approximately one year in age. The samples were analyzed for physicochemical properties as well as for the total chromium, copper, and arsenic concentrations. The chromium, copper, and arsenic concentrations in soil samples adjacent to the structures were as high as 79.0, 98.9, and 128 mg/kg, respectively, compared to background soil samples (48.2, 26.9, and 6.27 mg/kg, respectively). Arsenic was more mobile in soil than chromium and copper. The concentration gradient of arsenic in soil was observed only to the depth of approximately 5 cm in one year of outdoor exposure, whereas chromium and copper apparently remained near the surface (approximately less than 1 cm) after their release. Future efforts should be made to observe seasonal impacts on the release of metals and incorporate metal speciation into determining more detailed mobility and distribution.
Boards of CCA-treated wood, control (untreated) wood, and recycled plastic 'lumber' were placed into an estuary (Fort Pond, Southampton, NY, USA) in early May and examined monthly for abundance of species. One set of boards was left in the water continuously for 5 mo. Another set was renewed each month; after counting, organisms were removed and analyzed for dry weight and metal concentrations. A further set, placed in Accabonac Harbor, East Hampton, NY, in early July, compared CCA-treated wood that had not been impregnated well (green did not extend to inner portions), wood that had been well impregnated, and control wood. These boards were left in the water for 2 mo, and examined every 2 wk. Treated wood had a reduced number of species, lower diversity index, fewer barnacles (Balanus eburneus) and reduced growth of the barnacles that settled, fewer Membranipora and reduced growth of Membranipora colonies, fewer macroalgae, and fewer amphipods, compared to control wood and plastic. The bryozoan Bugula turrita, however, was found at great density on the treated wood. Biomass was lower on treated wood compared to control wood and plastic, and accumulations of Cu, Cr, and As were found. Barnacles initially avoided settling on plastic, but after 1 mo exceeded those on control wood. The communities in the 2 estuaries differed: e.g. at Accabonac species number was lower, there was less algae, bryozoans were absent, and barnacles were more dominant.
It has been observed previously that the digestive gland of the carnivorous gastropod mollusc, Murex trunculus, does not accumulate metals which occur in high concentration in the digestive gland of its prey, the detritus-feeding gastropod, Cerithium vulgatum. It is proposed that mechanisms of metal detoxification which operate in C. vulgatum render metals biologically unavailable to M. trunculus. In the present work, this scheme is tested by feeding tissues containing detoxified metals from a gastropod, bivalve and barnacle to carnivorous gastropods. Metals in the prey are accumulated in insoluble granules in the digestive gland of the gastropod, kidney of the bivalve and gut connective tissue of the barnacle. These tissues are fed to the carnivores and the granules pass through the entire length of the gut. They are egested as clean preparations within the faecal pellets and they still contain the metals introduced by the tissues of the prey. This transfer of detoxification between species indicates that the food chain progression of material can result in the reduction of the bioavailability of metals. The observations are recorded by scanning electron microscopy and X-ray microanalysis.
We tested the hypothesis that exposure-related alterations in the subcellular Cd distribution in prey relate to changes in
Cd absorption by a predator. Oligochaete worms,Limnodrilus hoffmeisteri were exposed for 1 wk or 6 wk to 0.5 μg Cd 1−1, 47 μg Cd 1−1, or 140 μg Cd 1−1 (including109Cd as a tracer) and relationships between oligochaete subcellular Cd distribution and Cd absorption by a predator, the grass
shrimp (Palaemonetes pugio), were determined. Concentration and duration of Cd exposure had direct effects on oligochaete subcellular Cd distribution.
Changes in oligochaete subcellular Cd distribution were characterized by increases in both the amount and proportion of Cd
bound to the cytosolic fraction. The induction of Cd-binding proteins (e.g., metallothioneins) were suspected to be responsible
for these changes. We found 1∶1 relationships between the amount and percentage of Cd in oligochaete cytosol and the amount
and percentage of Cd adsorbed by shrimp. These results demonstrate that only metal bound to the soluble fraction of prey is
available to higher trophic levels, and that factors influencing subcellular metal distribution in prey will directly alter
metal trophic transfer to predators.
This review summarizes information obtained from published literature to determine to what degree biomagnification of organic compounds and metals occurs in freshwater and marine food webs. This review was conducted by: (1) examining data from studies conducted in laboratory experiments to establish body burden ratios between trophic levels (trophic transfer coefficients; TTCs); (2) comparing laboratory-derived TTCs with data obtained from field studies; and (3) comparing biomagnification predictions described by published aquatic food-web models with data obtained in this review. It was determined that: (1) the majority of chemicals evaluated (both organic and metals) do not biomagnify in aquatic food webs; (2) for many of the compounds examined, considerable trophic transfer does occur in aquatic food webs; (3) DDT, DDE, PCBs, toxaphene, methyl mercury, total mercury, and arsenic have the potential to biomagnify in aquatic systems; (4) the lipid fraction of receptors directly influences biomagnification of lipophilic compounds; (5) the food web model reviewed provided similar estimates for most of the organic compounds examined (log Kow values between 5 and 7), with model predictions falling within the range of values of all compounds except dieldrin; (6) for many organic compounds, lack of information precludes assessing the relative importance of biomagnification for these contaminants; and (7) even those compounds for which evidence for biomagnification is strongest show considerable variability and uncertainty regarding the magnitude and existence of food-web biomagnification in aquatic systems.
The transport and impact of toxic substances are matters of major concern to management of coastal zones. Man’s love for the coastline and its attendant bays and estuaries ensures that, as population and industrial growth continue, the loading of toxic substances into estuaries and the coastal ocean will continue to increase. It is imperative, therefore, that society address the potential toxic effect of anthropogenic inputs to these areas. However, there are two impediments to successfully addressing these concerns.
Phytoplankton take up As(V) readily, and incorporate a small percentage of it into the cell. The majority of the As(V) is reduced, methylated, and released to the surrounding media. This uptake and subsequent release in a reduced or methylated form causes large changes in the speciation of arsenic in the culture media; up to 50% of the As(V) may be reduced. The speciation of arsenic in phytoplankton and Valonia also changes when As(V) is added to cultures. The addition generally causes an increase in the proportion of organic arsenic. Arsenate and phosphate compete for uptake by algal cells. The uptake and subsequent reduction and methylation of As(V) is a significant factor in determining the arsenic biogeochemistry of productive systems. Calculations based on the measured rates of reduction indicate that 15–20% of the total arsenic is reduced by phytoplankton during the spring and fall blooms on the continental shelf.
Panels of chromated copper arsenate (CCA)-treated wood and control (untreated) wood were placed into an estuary and examined after one month for differences in settlement of organisms. The community on the CCA wood exhibited greatly reduced species richness, biomass, and diversity. When the community on each panel (treated and untreated) was removed and the boards replaced into the estuary, the epibiota settling during the following month showed a smaller difference between the CCA panels and the control wood. After removal of the community and immersion of the wood for a third month, there were no statistically significant differences in the community that formed on the two materials. However, qualitative differences were still visible, particularly in the growth of the alga Enteromorpha and the bryozoan Conopeum. Differences in algal and bryozoan cover persisted after a year of submersion. The decreased toxicity of the CCA wood with repeated trials is probably related to decreased rate of leaching, as observed earlier in laboratory experiments, and suggests that the treated wood would have reduced environmental impact if it were soaked out at the treatment facility before being marketed for use in the aquatic environment. Bioaccumulation of the metals in the epibiota on the CCA wood generally declined over time, but remained far above control levels.
Green algae, Ulva lactuca (L.) and Entermorpha intestinalis (L.), were collected from bulkheads made of wood treated with chromated copper arsenate (CCA). Control algae were collected from nearby rocks. metal levels in the Ulva and Entermorpha from the CCA dock were elevated substantially over control levels. Snails, Nassarius obsoletus (Say), collected from an area from CCA-wood, were placed with control or experimental Ulva or Entermorphia. Snails feeding on experimental Ulva retracted into their shells and lay inactive on the bottom of the containers, a process that preceded death. Snails eating Entermorpha followed. By 4 wk, all the experimental snails were retracted or dead, while all control snails remained active. Thus, metals in the treated wood are taken up by attached algae, and can be toxic go grazing herbivores. Oysters, Crassostrea virginica (Gmelin), were collected from a CCA dock, a bulkhead in a canal lined with CCA wood, and rocks (reference site). Animals from the single dock had elevated Cu, and those from the bulkhead had 12 times the reference levels of Cu, and significantly elevated as. Fiddler crabs, Ucapugilator (Bosc) and U. panacea (Salmon), were collected from burrows close to or distant from CCA-treated wood structures and were analysed for metal content. Those living near CCA wood had elevated metal content, as did the sediments in which they resided. This indicates that sediments, which can absorb contaminants leached from CCA wood, are a route of exposure of benthic biota of these contaminants.
Oysters, Crassostrea virginica (Gmelin), collected from a residential canal lined with wood treated with chromated copper arsenate (CCA) had elevated levels of the metals in their tissues. Snails, Thais (Stramonita) haemastoma floridana (Conrad), fed the oysters gradually ate less than snails fed reference oysters, and grew less over an 8-wk period. Snails that ate the canal oysters increased their body burden of copper about 4-fold over the 8 weeks, and had tissue concentrations comparable to field-collected snails gathered from a CCA bulkhead in open water. Thais specimens were not found within the canal. Juvenile fish (Leiostomus xanthurus Lacepede and Lagodon rhomboides Linn.) were fed worms (primarily Neanthes succinea Frey and Leuckart) collected from sediments adjacent to a CCA bulkhead facing open water. These worms had elevated concentrations of the metals compared to worms from a reference site. Over a 1-month period, there was a non-significant trend of lower survival offish fed contaminated worms compared to those fed reference worms. There was no significant difference in growth. Body burdens of these fish were not significantly elevated by this exposure, although field-collected fish from inside the canal had significantly higher concentrations of Cu and As than did fish from the reference site.
Naturally occurring organics in samples taken from the mesohaline portion of a Chesapeake Bay tributary were separated into four nominal molecular weight fractions and analyzed for their ability to bind copper by using an algal bioassay. The organics exhibited a relatively high capacity for copper, with the binding capacity directly proportional to dissolved organic carbon (DOC) concentrations. The relationship between binding capacity and DOC is similar in the Chesapeake Bay and in other estuaries and marine ecosystems. Such correlation is not found in freshwater ecosystems. The strong relationship between DOC concentrations and binding capacities in marine ecosystems may be due to the autochthonous origin of marine organics. 44 references, 3 figures, 2 tables.
SANDERSON S. W., WILLIAMS G., BALLENGER T. and BERRY B. J. L. (1987) Impacts of computer-aided manufacturing on offshore assembly and future manufacturing locations, Reg. Studies 21, 131--142. Multinational firms are rethinking their strategies for manufacturing in the face of increased international competition and global markets. New technologies, such as computer-aided manufacturing and robotics, have the potential for altering location decisions, in particular co-production activities between developed and developing countries. This paper develops unit cost models for comparing manual offshore assembly in Mexico and Singapore with automated manufacturing in the United States. Results show that for the range of generally less-sophisticated products currently assembled there, Mexico retains its cost advantage for all volumes considered. However, for volumes exceeding 310,000 units per year, US flexible assembly begins to show lower unit costs than manual assembly in Singapore. SANDERSON S. W., WILLIAMS G., BALLENGER T. et BERRY B. J. L. (1987) Effets de la fabrication informatisée sur les montages à l'étranger et les futurs lieux de fabrication, Reg. Studies 21, 131--142. Les entreprises multinationales révisent leurs stratégies de fabrication face à l'accroissement de la compétition internationale et des marchés mondiaux. De nouvelles technologies telles la fabrication informatisée et la robotique ont le potentiel d'apporter des changements dans les décisions concernant les lieux de fabrication, en particulier dans les activités de coproduction entre pays développés et pays en voie de développement. Get article présente des modèles de coûts unitaires destinés à comparer les montages en pays étrangers , au Mexique et à Singapoure avec la fabrication automatisée aux Etats-Unis. Les résultats prouvent que pour l'éventail des produits généralement moins sophistiqués qui y sont actuellement assemblés, le Mexique conserve son avantage financier pour tous les volumes considérés. Cependant, pour les volumes dépassant 310,000 unités par an, le montage flexible US commence à montrer un coût unitaire inférieur à celui du montage manuel à Singapoure. SANDERSON S. W., WILLIAMS G., BALLENGER T. und BERRY B. J. L. (1987) Auswirkungen der industriellen Herstellung, bei der Computer eingeschaltet werden, auf Montagebau im Ausland und auf zukünftige Industriestandorte, Reg. Studies 21, 131--142. Angesichts zunehmenden internationalen Wettbewerbs und globaler Märkte überprüfen multinationale Firmen ihre Betriebstaktiken. Neue Technologien, wie die Einschaltung von Computern und Robotik in den Herstellungsprozess, sind im Stande, Entscheidungen bezüglich des Standortes umzustossen, insbesondere wo es sich um Zusammenarbeit von entwikkelten und sich entwickelnden Lündern bei gemeinsamer Produktion handelt. Diese Abhandlung entwickelt Kosteneinheitsmodelle für den Vergleich von Auslandsmontage in Handarbeit in Mexiko und Singapur mit vollautomatischer Produktion in den Vereinigten Staaten. Die Ergebnisse zeigen, dass bei allen Volumen, die in Betracht gezogen werden, Mexiko seine Kostenvorteile beibehält, solang es sich an den Bereich allgemein weniger hochentwickelter Produkte hält, die gegewärtig dort hergestellt werden. Bei Volumen, die 310 000 Einheiten pro Jahr überschreiten, beginnt die flexible Montage der USA jedoch niedrigere Kosten per Einheit aufzuweisen als die Handarbeit in Singapur.
Intestinal uptake and transport of cadmium (Cd) to different organs were studied in control and oral zinc pretreated rats using an in situ intestinal loop model. Intestinal loop was incubated with either CdCl2 or Cd-metallothionein (Cd-MT) for 30 and 60 min in rats under anesthesia. Induction of MT by oral Zn pretreatment had little effect on intestinal uptake of Cd ion. However, when intestinal loop was incubated with exogenous Cd-MT, the uptake of Cd was significantly smaller than that from CdCl2 incubation. About 50% of the Cd in the intestine of control rat after CdCl2 incubation was recovered in the cytosol fraction and bound to high-molecular-weight (greater than 60 kDa) proteins. In both Zn pretreated rats incubated with CdCl2 and control rats incubated with Cd-MT, Cd was mostly recovered in the intestinal cytosol fraction (75-85%) and was mainly bound to MT. After 60 min incubation of control intestinal loop with CdCl2. Cd was detected mainly in liver with small amounts in kidney and pancreas: with Cd-MT incubation, Cd was detected only in the kidney. The deposition of Cd in the liver was markedly decreased by Zn pretreatment. Both the uptake of Cd-MT by intestine and the induction of MT synthesis in the intestine by Zn pretreatment were demonstrated by immunohistochemistry using a specific antibody to rat liver MT. The results suggest a slow uptake of exogenous Cd-MT from the intestine and transport to kidney in contrast to deposition of Cd in the liver from CdCl2. Although the intracellular presence of MT does not affect the uptake of Cd from lumen, it may decrease both the release of Cd from the intestine and its deposition in liver.
The bioaccumulation of trace elements in aquatic organisms can be described with a kinetic model that includes linear expressions for uptake and elimination from dissolved and dietary sources. Within this model, trace element trophic transfer is described by four parameters: the weight-specific ingestion rate (IR); the assimilation efficiency (AE); the physiological loss rate constant (ke); and the weight-specific growth rate (g). These four parameters define the trace element trophic transfer potential (TTP = IR.AE/[ke + g]) which is equal to the ratio of the steady-state trace element concentration in a consumer due to trophic accumulation to that in its prey. Recent work devoted to the quantification of AE and ke for a variety of trace elements in aquatic invertebrates has provided the data needed for comparative studies of trace element trophic transfer among different species and trophic levels and, in at least one group of aquatic consumers (marine bivalves), sensitivity analyses and field tests of kinetic bioaccumulation models. Analysis of the trophic transfer potentials of trace elements for which data are available in zooplankton, bivalves, and fish, suggests that slight variations in assimilation efficiency or elimination rate constant may determine whether or not some trace elements (Cd, Se, and Zn) are biomagnified. A linear, single-compartment model may not be appropriate for fish which, unlike many aquatic invertebrates, have a large mass of tissue in which the concentrations of most trace elements are subject to feedback regulation.
The efficiency with which a variety of ingested elements (Ag, Am, C, Cd, P, S, Se, and Zn) were assimilated in marine calanoid
copepods fed uniformly radiolabeled diatoms ranged from 0.9% for Am to 97.1% for Se. Assimilation efficiencies were directly
related to the cytoplasmic content of the diatoms. This relation indicates that the animals obtained nearly all their nutrition
from this source. The results suggest that these zooplankton, which have short gut residence times, have developed a gut lining
and digestive strategy that provides for assimilation of only soluble material. Because the fraction of total cellular protein
in the cytoplasm of the diatoms increased markedly with culture age, copepods feeding on senescent cells should obtain more
protein than those feeding on rapidly dividing cells. Elements that are appreciably incorporated into algal cytoplasm and
assimilated in zooplankton should be recycled in surface waters and have longer oceanic residence times than elements bound
to cell surfaces.