The Experts below are selected from a list of 14769 Experts worldwide ranked by ideXlab platform
Ian L Pepper - One of the best experts on this subject based on the ideXlab platform.
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Comparative Assessment of BGM and PLC/PRF/5 Cell Lines for Enteric Virus Detection in Biosolids
Food and Environmental Virology, 2019Co-Authors: Sherif Abd-elmaksoud, N. Castro-del Campo, Ian L. Pepper, Charles P. Gerba, Charles P Gerba, Ian L Pepper, Kelly R. BrightAbstract:The buffalo green monkey (BGM) cell line is required for the detection of enteric viruses in Biosolids through a total culturable viral assay (TCVA) by the United States Environmental Protection Agency. In the present study, BGM and PLC/PRF/5 cell lines were evaluated for TCVA and for their use in determining the incidence of adenoviruses and enteroviruses in raw sludge and Class B Biosolids. Six raw sludge and 17 Class B Biosolid samples were collected from 13 wastewater treatment plants from seven U.S. states. Samples were processed via organic flocculation and concentrate volumes equivalent to 4 g total solids were assayed on BGM and PLC/PRF/5 cells. Cell monolayers were observed for cytopathic effect (CPE) after two 14-days passages. Cell lysates were tested for the presence of adenoviruses and enteroviruses by PCR or RT-PCR. The PLC/PRF/5 cells detected more culturable viruses than the BGM cells by CPE (73.9% vs. 56.5%, respectively). 52% of the samples were positive for CPE using both cell lines. No viruses were detected in either cell line by PCR in flasks in which CPE was not observed. No adenoviruses were detected in 13 CPE-positive samples from BGM lysates. In contrast, of the 17 samples exhibiting CPE on PLC/PRF/5 cells, 14 were positive for adenoviruses (82.4%). In conclusion, PLC/PRF/5 cells were superior for the detection of adenoviruses in both raw sludge and Class B Biosolids. Thus, the use of BGM cells alone for TCVA may underestimate the viral concentration in sludge/Biosolid samples.
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long term effects of land application of class b Biosolids on the soil microbial populations pathogens and activity
Journal of Environmental Quality, 2010Co-Authors: Huruy Zerzghi, John P Brooks, Charles P Gerba, Ian L PepperAbstract:This study evaluated the influence of 20 annual land applications of Class B Biosolids on the soil microbial community. The potential benefits and hazards of land application were evaluated by analysis of surface soil samples collected following the 20th land application of Biosolids. The study was initiated in 1986 at the University of Arizona Marana Agricultural Center, 21 miles north of Tucson, AZ. The final application of Biosolids was in March 2005, followed by growth of cotton (Gossypium hirsutum L.) from April through November 2005. Surface soil samples (0—30 cm) were collected monthly from March 2005, 2 wk after the final Biosolids application, through December 2005, and analyzed for soil microbial numbers. December samples were analyzed for additional soil microbial properties. Data show that land application of Class B Biosolids had no significant long-term effect on indigenous soil microbial numbers including bacteria, actinomycetes, and fungi compared to unamended control plots. Importantly, no bacterial or viral pathogens were detected in soil samples collected from Biosolid amended plots in December (10 mo after the last land application) demonstrating that pathogens introduced via Class B Biosolids only survived in soil transiently. However, plots that received Biosolids had significantly higher microbial activity or potential for microbial transformations, including nitrification, sulfur oxidation, and dehydrogenase activity, than control plots and plots receiving inorganic fertilizers. Overall, the 20 annual land applications showed no long-term adverse effects, and therefore, this study documents that land application of Biosolids at this particular site was sustainable throughout the 20-yr period, with respect to soil microbial properties.
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Potential Regrowth and Recolonization of Salmonellae and Indicators in Biosolids and Biosolid-Amended Soil
Applied and Environmental Microbiology, 2005Co-Authors: Kathleen J. Zaleski, Charles P Gerba, K. L. Josephson, Ian L PepperAbstract:This study evaluated the potential for conversion of Class B to Class A Biosolids with respect to salmonellae and fecal coliforms during solar drying in concrete lined drying beds. Anaerobically (8% solids) and aerobically (2% solids) digested Class B Biosolids were pumped into field-scale drying beds, and microbial populations and environmental conditions were monitored. Numbers of fecal coliforms and salmonellae decreased as temperature and rate of desiccation increased. After 3 to 4 weeks, Class A requirements were achieved in both Biosolids for the pathogens and the indicators. However, following rainfall events, significant increase in numbers was observed for both fecal coliforms and salmonellae. In laboratory studies, regrowth of fecal coliforms was observed in both Biosolids and Biosolid-amended soil, but the regrowth of salmonellae observed in the concrete-lined drying beds did not occur. These laboratory studies demonstrated that pathogens decreased in numbers when soil was amended with Biosolids. Based on serotyping, the increased numbers of salmonellae seen in the concrete lined drying beds following rainfall events was most likely due to recolonization due to contamination from fecal matter introduced by animals and not from regrowth of salmonellae indigenous to Biosolids. Overall, we conclude that the use of concrete-lined beds created a situation in which moisture added as rainfall accumulated in the beds, promoting the growth of fecal coliforms and salmonellae added from external sources.
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Evidence for the absence of Staphylococcus aureus in land applied Biosolids
Environmental Science & Technology, 2003Co-Authors: Patricia A. Rusin, Sheri L. Maxwell, John P Brooks, Charles P Gerba, Ian L PepperAbstract:Staphylococcus aureus is an important human pathogen both within the hospital setting and as a community-acquired infection. Recently there has been concern that land applied Biosolids may transmit S. aureus. However, no scientific data are available to document whether Biosolids are a source of S. aureus. To determine if S. aureus is present in Biosolids, we collected samples from 15 sites across the United States. Samples analyzed were as follows: 3 raw untreated sewage samples and 2 undigested primary sewage sludge samples; 23 different Biosolid samples; and 27 aerosols obtained during Biosolid land application (Biosolid aerosols). Although S. aureus were detected in raw sewage samples, none were found in any of the treated Biosolids nor in any Biosolid aerosol samples. These results suggest that Biosolids are not a likely source of S. aureus human exposure or infection.
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bioaerosol transport modeling and risk assessment in relation to Biosolid placement
Journal of Environmental Quality, 2000Co-Authors: Scot E Dowd, Charles P Gerba, Ian L Pepper, Suresh D PillaiAbstract:A field study was performed in which bioaerosols were sampled at a field site undergoing land placement of anaerobically digested, de-watered Biosolid material. The data from these field studies were then used to generate microbial release rates from the Biosolids for use in modeling bioaerosol transport. Continuous-point sources represented by large Biosolid piles (temporary storage before placement) in the field, and continuous-area sources represented by large fields upon which Biosolids were placed by spraying, were modeled using microbial transport models; and downwind microbial concentrations were generated. These quantified transport data were then entered into microbial dose-response models in an attempt to characterize the risk of pathogenic bacteria and viruses infecting workers and nearby population centers. The risk of viral and bacterial infection to workers at Biosolid land application sites is 3:100 and 2:100, respectively, under 2-m/s wind conditions and 1 hr of exposure. The route of exposure proposed in this modelis the transport, inhalation, deposition, and swallowing of bacterial or viral pathogens. Note that these risk models by nature would tend to overestimate the actual risk to populations (wastewater workers) consisting primarily of immunocompetent individuals. Under these low-wind conditions, nearby population centers where such immunocompetent populations may exist (here considered to be 10000 m from the land application sites) are predicted to be at little risk (1.95 x 10 -2 :100) of infection from aerosolized bacteria and at no risk from aerosolized viruses.
Charles P Gerba - One of the best experts on this subject based on the ideXlab platform.
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Comparative Assessment of BGM and PLC/PRF/5 Cell Lines for Enteric Virus Detection in Biosolids
Food and Environmental Virology, 2019Co-Authors: Sherif Abd-elmaksoud, N. Castro-del Campo, Ian L. Pepper, Charles P. Gerba, Charles P Gerba, Ian L Pepper, Kelly R. BrightAbstract:The buffalo green monkey (BGM) cell line is required for the detection of enteric viruses in Biosolids through a total culturable viral assay (TCVA) by the United States Environmental Protection Agency. In the present study, BGM and PLC/PRF/5 cell lines were evaluated for TCVA and for their use in determining the incidence of adenoviruses and enteroviruses in raw sludge and Class B Biosolids. Six raw sludge and 17 Class B Biosolid samples were collected from 13 wastewater treatment plants from seven U.S. states. Samples were processed via organic flocculation and concentrate volumes equivalent to 4 g total solids were assayed on BGM and PLC/PRF/5 cells. Cell monolayers were observed for cytopathic effect (CPE) after two 14-days passages. Cell lysates were tested for the presence of adenoviruses and enteroviruses by PCR or RT-PCR. The PLC/PRF/5 cells detected more culturable viruses than the BGM cells by CPE (73.9% vs. 56.5%, respectively). 52% of the samples were positive for CPE using both cell lines. No viruses were detected in either cell line by PCR in flasks in which CPE was not observed. No adenoviruses were detected in 13 CPE-positive samples from BGM lysates. In contrast, of the 17 samples exhibiting CPE on PLC/PRF/5 cells, 14 were positive for adenoviruses (82.4%). In conclusion, PLC/PRF/5 cells were superior for the detection of adenoviruses in both raw sludge and Class B Biosolids. Thus, the use of BGM cells alone for TCVA may underestimate the viral concentration in sludge/Biosolid samples.
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long term effects of land application of class b Biosolids on the soil microbial populations pathogens and activity
Journal of Environmental Quality, 2010Co-Authors: Huruy Zerzghi, John P Brooks, Charles P Gerba, Ian L PepperAbstract:This study evaluated the influence of 20 annual land applications of Class B Biosolids on the soil microbial community. The potential benefits and hazards of land application were evaluated by analysis of surface soil samples collected following the 20th land application of Biosolids. The study was initiated in 1986 at the University of Arizona Marana Agricultural Center, 21 miles north of Tucson, AZ. The final application of Biosolids was in March 2005, followed by growth of cotton (Gossypium hirsutum L.) from April through November 2005. Surface soil samples (0—30 cm) were collected monthly from March 2005, 2 wk after the final Biosolids application, through December 2005, and analyzed for soil microbial numbers. December samples were analyzed for additional soil microbial properties. Data show that land application of Class B Biosolids had no significant long-term effect on indigenous soil microbial numbers including bacteria, actinomycetes, and fungi compared to unamended control plots. Importantly, no bacterial or viral pathogens were detected in soil samples collected from Biosolid amended plots in December (10 mo after the last land application) demonstrating that pathogens introduced via Class B Biosolids only survived in soil transiently. However, plots that received Biosolids had significantly higher microbial activity or potential for microbial transformations, including nitrification, sulfur oxidation, and dehydrogenase activity, than control plots and plots receiving inorganic fertilizers. Overall, the 20 annual land applications showed no long-term adverse effects, and therefore, this study documents that land application of Biosolids at this particular site was sustainable throughout the 20-yr period, with respect to soil microbial properties.
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Potential Regrowth and Recolonization of Salmonellae and Indicators in Biosolids and Biosolid-Amended Soil
Applied and Environmental Microbiology, 2005Co-Authors: Kathleen J. Zaleski, Charles P Gerba, K. L. Josephson, Ian L PepperAbstract:This study evaluated the potential for conversion of Class B to Class A Biosolids with respect to salmonellae and fecal coliforms during solar drying in concrete lined drying beds. Anaerobically (8% solids) and aerobically (2% solids) digested Class B Biosolids were pumped into field-scale drying beds, and microbial populations and environmental conditions were monitored. Numbers of fecal coliforms and salmonellae decreased as temperature and rate of desiccation increased. After 3 to 4 weeks, Class A requirements were achieved in both Biosolids for the pathogens and the indicators. However, following rainfall events, significant increase in numbers was observed for both fecal coliforms and salmonellae. In laboratory studies, regrowth of fecal coliforms was observed in both Biosolids and Biosolid-amended soil, but the regrowth of salmonellae observed in the concrete-lined drying beds did not occur. These laboratory studies demonstrated that pathogens decreased in numbers when soil was amended with Biosolids. Based on serotyping, the increased numbers of salmonellae seen in the concrete lined drying beds following rainfall events was most likely due to recolonization due to contamination from fecal matter introduced by animals and not from regrowth of salmonellae indigenous to Biosolids. Overall, we conclude that the use of concrete-lined beds created a situation in which moisture added as rainfall accumulated in the beds, promoting the growth of fecal coliforms and salmonellae added from external sources.
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Evidence for the absence of Staphylococcus aureus in land applied Biosolids
Environmental Science & Technology, 2003Co-Authors: Patricia A. Rusin, Sheri L. Maxwell, John P Brooks, Charles P Gerba, Ian L PepperAbstract:Staphylococcus aureus is an important human pathogen both within the hospital setting and as a community-acquired infection. Recently there has been concern that land applied Biosolids may transmit S. aureus. However, no scientific data are available to document whether Biosolids are a source of S. aureus. To determine if S. aureus is present in Biosolids, we collected samples from 15 sites across the United States. Samples analyzed were as follows: 3 raw untreated sewage samples and 2 undigested primary sewage sludge samples; 23 different Biosolid samples; and 27 aerosols obtained during Biosolid land application (Biosolid aerosols). Although S. aureus were detected in raw sewage samples, none were found in any of the treated Biosolids nor in any Biosolid aerosol samples. These results suggest that Biosolids are not a likely source of S. aureus human exposure or infection.
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bioaerosol transport modeling and risk assessment in relation to Biosolid placement
Journal of Environmental Quality, 2000Co-Authors: Scot E Dowd, Charles P Gerba, Ian L Pepper, Suresh D PillaiAbstract:A field study was performed in which bioaerosols were sampled at a field site undergoing land placement of anaerobically digested, de-watered Biosolid material. The data from these field studies were then used to generate microbial release rates from the Biosolids for use in modeling bioaerosol transport. Continuous-point sources represented by large Biosolid piles (temporary storage before placement) in the field, and continuous-area sources represented by large fields upon which Biosolids were placed by spraying, were modeled using microbial transport models; and downwind microbial concentrations were generated. These quantified transport data were then entered into microbial dose-response models in an attempt to characterize the risk of pathogenic bacteria and viruses infecting workers and nearby population centers. The risk of viral and bacterial infection to workers at Biosolid land application sites is 3:100 and 2:100, respectively, under 2-m/s wind conditions and 1 hr of exposure. The route of exposure proposed in this modelis the transport, inhalation, deposition, and swallowing of bacterial or viral pathogens. Note that these risk models by nature would tend to overestimate the actual risk to populations (wastewater workers) consisting primarily of immunocompetent individuals. Under these low-wind conditions, nearby population centers where such immunocompetent populations may exist (here considered to be 10000 m from the land application sites) are predicted to be at little risk (1.95 x 10 -2 :100) of infection from aerosolized bacteria and at no risk from aerosolized viruses.
Brett P Goodman - One of the best experts on this subject based on the ideXlab platform.
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beneficial or biohazard how the media frame Biosolids
Public Understanding of Science, 2006Co-Authors: Robyn J Goodman, Brett P GoodmanAbstract:This study looked at how the media framed Biosolids, or treated sewage sludge, from 1994 to 2004 by analyzing the 13 media frames found in 286 Biosolid-related articles from newspapers in Florida, Virginia, and California. The researchers found the articles framed Biosolids as a regulatory or legal issue most often, and most of the frames’ tones were neutral (1,958). However, negative tone (507) happened three times more often than positive tone (149), and environmental, management, and public nuisance framing tended to be more negative than any of the other frames. Neither the frames themselves nor the tones had statistically significant changes over the past decade. Regarding the sources used in the stories, the most frequent source was local government officials, which were used twice as frequently as any other source, followed by corporations (16 percent) and citizens (14 percent). These findings should help Biosolid producers and officials in developing a media strategy that is proactive toward shapi...
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Beneficial or biohazard? How the media frame Biosolids
Public Understanding of Science, 2006Co-Authors: J. Robyn Goodman, Brett P GoodmanAbstract:This study looked at how the media framed Biosolids, or treated sewage sludge, from 1994 to 2004 by analyzing the 13 media frames found in 286 Biosolid-related articles from newspapers in Florida, Virginia, and California. The researchers found the articles framed Biosolids as a regulatory or legal issue most often, and most of the frames' tones were neutral (1,958). However, negative tone (507) happened three times more often than positive tone (149), and environmental, management, and public nuisance framing tended to be more negative than any of the other frames. Neither the frames themselves nor the tones had statistically significant changes over the past decade. Regarding the sources used in the stories, the most frequent source was local government officials, which were used twice as frequently as any other source, followed by corporations (16 percent) and citizens (14 percent). These findings should help Biosolid producers and officials in developing a media strategy that is proactive toward shaping public opinion rather than reactive to an issue that makes its way to the media and spurs public concern.
Peter Christie - One of the best experts on this subject based on the ideXlab platform.
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a field study of the fate of Biosolid borne silver in the soil crop system
Environmental Pollution, 2020Co-Authors: Lu Yang, Peter Christie, Yongming LuoAbstract:Abstract Land application of Biosolids is a major route for the introduction of silver (Ag) into the terrestrial environment. Previous studies have focused on the risks from Ag to the human food chain but there is still a lack of quantitative information on the flow of Biosolid-borne Ag in the soil-crop system. Two long-term field experiments were selected to provide contrasting soil properties and tillage crops to investigate the fate of Ag from sequentially applied Biosolids. Biosolid-borne Ag accumulated in the soil and
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influence of long term Biosolid applications on communities of soil fauna and their metal accumulation a field study
Environmental Pollution, 2020Co-Authors: Li Zhu, Yongming Luo, Peter ChristieAbstract:Amendment with sewage sludge or Biosolids can increase soil fertility but may also transfer Biosolid-borne pollutants to the soil and the possible effects on the soil ecosystem are poorly understood, especially long-term effects. A long-term experiment was therefore established to assess the effects of repeated applications of different types of Biosolids (fresh domestic, dried domestic and fresh industrial sludges) in field conditions. Nine years of sludge application led to changes in soil chemical and biological properties and generally contributed little to soil nutrient status. However, soil concentrations of potentially toxic elements (PTEs) were elevated by amendment, especially with industrial Biosolids. Soil fauna are usually used to decipher the underlying effects of Biosolid applications on the soil ecosystem. Here, collembolans (50.9%), nematodes (41.6%) and enchytraeid worms (7.50%) were collected and differentiated into different ecological and trophic groups and their body lengths and PTE concentrations in the body tissues were investigated. The animals showed different responses to the Biosolids at population and individual levels. There were substantial changes in epigeic collembolan communities and bacterivorous nematodes increased significantly after Biosolid amendment. Biosolid-borne PTEs were major factors and Redundancy (RDA) analysis indicates that collembolan communities were strongly influenced by zinc (Zn). The three groups of soil animals showed similar trends in accumulation of PTEs in the sequence cadmium (Cd) > Zn > copper (Cu), and the bioaccumulation factor (BAF) values of the PTEs were significantly higher in the industrial sludge treatment than in other two treatments with a similar trend of decreasing body length of nematodes. The results indicate that it is potentially risky to use industrial Biosolids in the long term, and different species and ecological groups of collembolans and different trophic groups of nematodes should be examined when assessing soil health.
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Dissipation of antibiotics in three different agricultural soils after repeated application of Biosolids
Environmental Science and Pollution Research, 2016Co-Authors: Lu Yang, Longhua Wu, Yujuan Huang, Peter ChristieAbstract:Application of Biosolids to agricultural soils is one of the pathways by which antibiotics can be introduced into agricultural ecosystems. A pot experiment was conducted with repeated soil amendment with Biosolids to examine the concentrations of four classes of antibiotics (tetracyclines, sulfonamides, fluoroquinolones, and macrolides) and their dissipation in three different soil types in wheat-rice rotations. Antibiotics accumulate in the soils after repeated application of Biosolids. Fluoroquinolones showed stronger accumulation and persistence in the test soils than the other three classes of antibiotics. The maximum residual antibiotic concentration was that of norfloxacin at 155 ± 16 μg kg−1 in the Typic Hapli-Stagnic Anthrosols (paddy soil). Predicted half-lives were up to 3.69 years, a much longer period than that between Biosolid applications (twice each year on average). Antibiotic accumulation followed the rough order fluoroquinolones > tetracyclines > macrolides > sulfonamides, and the sulfonamides were seldom encountered. When Biosolid application was suspended, the dissipation rate accelerated. Antibiotic dissipation was slightly slower when Biosolids with high heavy metal concentrations were applied and microbial degradation may have been the main mechanism of dissipation. Norfloxacin persistence was positively correlated with its soil adsorption capacity. Cation exchange capacity and soil organic matter content may have vital roles in the soil adsorption of fluoroquinolones. Because of their persistence, the fluoroquinolones must be taken into account in the planning of Biosolid applications in agricultural practice.
Feng Chen - One of the best experts on this subject based on the ideXlab platform.
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field dissipation and plant uptake of benzotriazole ultraviolet stabilizers in Biosolid amended soils
Environmental Science: Processes & Impacts, 2014Co-Authors: Huajie Lai, Zhifeng Chen, Guangguo Ying, Feng Chen, Yousheng LiuAbstract:Benzotriazole ultraviolet stabilizers (BUVSs) have been commonly used in industrial and household product formulations, and have been detected in Biosolids from wastewater treatment plants. However, little is known about their occurrence and dissipation behavior in the soil environment associated with Biosolid application. This study investigated the occurrence and dissipation of five typical BUVSs (UV-326, UV-327, UV-328, UV-329 and UV-P) in Biosolid-amended soils, and the uptake of these biocides by plants. The field trial includes two treatment groups: old groups with Biosolid application at rates of 5, 10, 20 and 40 t ha−1 every year within 5 years, and new groups with only one Biosolid application. The results showed that the five BUVSs could be detected in most Biosolid-amended soils at a few to tens of ng g−1 levels, but not detected in the control soils. These chemicals were not found in the crop plants collected from the trial plots. Moreover, high Biosolid application rates and repeated Biosolid applications resulted in high accumulation of these BUVSs in soil. During one year monitoring, the five BUVSs were significantly dissipated in the Biosolid-amended soils with their half-lives ranging from 79 to 223 days, which were comparable with the modeling results. The results from this study demonstrated the persistence of BUVSs in soil environments with quite slow dissipation rates.
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field dissipation and risk assessment of typical personal care products tcc tcs ahtn and hhcb in Biosolid amended soils
Science of The Total Environment, 2014Co-Authors: Feng Chen, Zhifeng Chen, Guangguo Ying, Huajie Lai, Fengjiao PengAbstract:Abstract The antimicrobial agents triclocarban (TCC) and triclosan (TCS) and synthetic musks AHTN (Tonalide) and HHCB (Galaxolide) are widely used in many personal care products. These compounds may release into the soil environment through Biosolid application to agricultural land and potentially affect soil organisms. This paper aimed to investigate accumulation, dissipation and potential risks of TCC, TCS, AHTN and HHCB in Biosolid-amended soils of the three field trial sites (Zhejiang, Hunan and Shandong) with three treatments (CK: control without Biosolid application, T1: single Biosolid application, T2: repeated Biosolid application every year). The one-year monitoring results showed that Biosolids application could lead to accumulation of these four chemicals in the Biosolid-amended soils, with the residual concentrations in the following order: TCC > TCS > AHTN > HHCB. Dissipation of TCC, TCS, AHTN and HHCB in the Biosolid-amended soils followed the first-order kinetics model. Half-lives for TCC, TCS, AHTN and HHCB under the field conditions of Shandong site were 191, 258, 336 and 900 days for T1, and 51, 106, 159 and 83 days for T2, respectively. Repeated applications of Biosolid led to accumulation of these personal care products and result in higher ecological risks. Based on the residual levels in the trial sites and limited toxicity data, high risks to soil organisms are expected for TCC and TCS, while low-medium risks for AHTN and HHCB.
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occurrence and dissipation of three azole biocides climbazole clotrimazole and miconazole in Biosolid amended soils
Science of The Total Environment, 2013Co-Authors: Zhifeng Chen, Guangguo Ying, Feng ChenAbstract:This study investigated the occurrence and dissipation of three azole biocides climbazole, clotrimazole and miconazole in Biosolid-amended soils of the three sites (Zhejiang, Hunan and Shandong) in China following three treatments (CK: control without Biosolid application; T1: one Biosolid application; T2: Biosolid application every year). The results showed that climbazole, clotrimazole and miconazole were present in the Biosolid and Biosolid-amended soils, but absent in the control soils. In the soils treated with Biosolids, the concentrations of climbazole, clotrimazole and miconazole were mostly lower in the Zhejiang soils than in the Shandong or Hunan soils, suggesting that these three biocides are more readily dissipated under the flooding condition. During the one year monitoring, the concentrations of climbazole, clotrimazole and miconazole in the Biosolid-applied soils showed only slight variations. The dissipation half-lives for miconazole calculated under the field conditions of Shandong site were 440 days for T1 and the half-lives for clotrimazole were 365 days for T2. The results suggested the persistence of these three biocides in the soil environments.
