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Zhang R, Zhou Z, Zhu W. Evaluating the effects of the tebuconazole on the earthworm, Eisenia fetida by H-1 NMR-Based untargeted metabolomics and mRNA assay. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 194:110370. [PMID: 32151865 DOI: 10.1016/j.ecoenv.2020.110370] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 06/10/2023]
Abstract
Tebuconazole, a widely used fungicide, can severely disrupt the reproductive process of various organisms. In this study, we investigated the subacute effects of tebuconazole on the earthworm to fully understand its toxic implications. Herein, untargeted metabolomics, mRNA assay and biochemical approaches were adopted to evaluate the subacute effects of Eisenia fetida earthworms, when exposed to tebuconazole at three different concentrations (0.5, 5 and 50 mg/kg) for seven days. SOD enzyme activity test displayed that tebuconazole exposure interfered with the earthworms' ROS. ANN mRNA expression was down-regulated after tebuconazole exposure. 1H nuclear magnetic resonance (1H-NMR)-based untargeted metabolomics study showed that 5 mg/kg tebuconazole exposure interfered with earthworms' metabolism. Twelve significantly changed metabolites were identified. The pathway analyses indicate that tebuconazole can disrupt the earthworm's metabolism, particularly in the AMP pathway, which impact the reproduction. This may explain the tebuconazole's mechanism of action behind the down-regulation of the expression of ANN mRNA, which is related to the earthworm's reproductive process. We comprehensively evaluated the mRNA expression, enzyme activity, and metabolomics, and acquired sufficient information for evaluating the toxicity of tebuconazole.
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Affiliation(s)
- Renke Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing, 100193, China
| | - Zhiqiang Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing, 100193, China
| | - Wentao Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing, 100193, China.
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Dani VD, Lankadurai BP, Nagato EG, Simpson AJ, Simpson MJ. Comparison of metabolomic responses of earthworms to sub-lethal imidacloprid exposure in contact and soil tests. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:18846-18855. [PMID: 31065987 DOI: 10.1007/s11356-019-05302-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
Eisenia fetida earthworms were exposed to sub-lethal levels of imidacloprid for 48 h via contact filter paper tests and soil tests. After the exposure, 1H nuclear magnetic resonance (NMR) metabolomics was used to measure earthworm sub-lethal responses by analyzing the changes in the polar metabolite profile. Maltose, glucose, malate, lactate/threonine, myo-inositol, glutamate, arginine, lysine, tyrosine, leucine, and phenylalanine relative concentrations were altered with imidacloprid exposure in soil. In addition to these metabolites (excluding leucine and phenylalanine), fumarate, ATP, inosine, betaine, scyllo-inositol, glutamine, valine, tryptophan, alanine, tyrosine, and isoleucine relative concentrations shifted with imidacloprid exposure during contact tests. Metabolite changes in E. fetida earthworms exposed to imidacloprid showed a non-linear concentration response and an upregulation in gluconeogenesis. Overall, imidacloprid exposure in soil induces a less pronounced response in metabolites glucose, maltose, fumarate, adenosine-5'-triphosphate (ATP), inosine, scyllo-inositol, lactate/threonine, and tyrosine in comparison to the response observed via contact tests. Thus, our study highlights that tests in soil can result in a different metabolic response in E. fetida and demonstrates the importance of different modes of exposure and the extent of metabolic perturbation in earthworms. Our study also emphasizes the underlying metabolic disruption of earthworms after acute sub-lethal exposure to imidacloprid. These observations should be further examined in different soil types to assess the sub-lethal toxicity of imidacloprid to soil-dwelling earthworms.
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Affiliation(s)
- Vivek D Dani
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada
| | - Brian P Lankadurai
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada
| | - Edward G Nagato
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada
| | - André J Simpson
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada
| | - Myrna J Simpson
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada.
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada.
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Zhang R, Zhou Z. Effects of the Chiral Fungicides Metalaxyl and Metalaxyl-M on the Earthworm Eisenia fetida as Determined by ¹H-NMR-Based Untargeted Metabolomics. Molecules 2019; 24:molecules24071293. [PMID: 30987047 PMCID: PMC6479362 DOI: 10.3390/molecules24071293] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 03/29/2019] [Accepted: 03/30/2019] [Indexed: 02/06/2023] Open
Abstract
Although metalaxyl and metalaxyl-M are widely used fungicides, very little is known about their subacute and enantiospecific effects on the earthworm metabolome. In this study, Eisenia fetida were exposed to metalaxyl and metalaxyl-M at three concentrations (0.5, 5 and 50 mg/kg) for seven days. 1H nuclear magnetic resonance (1H-NMR)-based untargeted metabolomics showed that metalaxyl and metalaxyl-M exposure disturbed earthworms’ metabolism at all three concentrations. Endogenous metabolites, such as succinate, arginine, aspartate, urea, asparagine, alanine, trimethylamine, taurine, cysteine, serine, threonine, histidine, lysine, glucose, choline, carnitine, citric acid, alpha-ketoisovaleric acid, fumaric acid and so on, were significantly changed. These results indicate that metalaxyl and metalaxyl-M produce different, enantiospecific disturbances in the earthworm metabolism, particularly in the tricarboxylic acid (TCA) and urea cycles. The application of untargeted metabolomics thus provides more information for evaluating the toxic risks of metalaxyl and metalaxyl-M.
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Affiliation(s)
- Renke Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, China.
| | - Zhiqiang Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, China.
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Tang R, Ding C, Dang F, Ma Y, Wang J, Zhang T, Wang X. NMR-based metabolic toxicity of low-level Hg exposure to earthworms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 239:428-437. [PMID: 29679940 DOI: 10.1016/j.envpol.2018.04.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
Mercury is a globally distributed toxicant to aquatic animals and mammals. However, the potential risks of environmental relevant mercury in terrestrial systems remain largely unclear. The metabolic profiles of the earthworm Eisenia fetida after exposure to soil contaminated with mercury at 0.77 ± 0.09 mg/kg for 2 weeks were investigated using a two-dimensional nuclear magnetic resonance-based (1H-13C NMR) metabolomics approach. The results revealed that traditional endpoints (e.g., mortality and weight loss) did not differ significantly after exposure. Although histological examination showed sub-lethal toxicity in the intestine as a result of soil ingestion, the underlying mechanisms were unclear. Metabolite profiles revealed significant decreases in glutamine and 2-hexyl-5-ethyl-3-furansulfonate in the exposed group and remarkable increases in glycine, alanine, glutamate, scyllo-inositol, t-methylhistidine and myo-inositol. More importantly, metabolic network analysis revealed that low mercury in the soil disrupted osmoregulation, amino acid and energy metabolisms in earthworms. A metabolic net link and schematic diagram of mercury-induced responses were proposed to predict earthworm responses after exposure to mercury at environmental relevant concentrations. These results improved the current understanding of the potential toxicity of low mercury in terrestrial systems.
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Affiliation(s)
- Ronggui Tang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China; University of the Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Changfeng Ding
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Fei Dang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Yibing Ma
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
| | - Junsong Wang
- Center for Molecular Metabolism, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210014, People's Republic of China
| | - Taolin Zhang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Xingxiang Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China.
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Dani VD, Simpson AJ, Simpson MJ. Analysis of earthworm sublethal toxic responses to atrazine exposure using 1 H nuclear magnetic resonance (NMR)-based metabolomics. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:473-480. [PMID: 28888035 DOI: 10.1002/etc.3978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/10/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
Atrazine toxicity to earthworms is still not fully understood, particularly at sublethal concentrations. Because of the ubiquity of atrazine in the environment, it is imperative to understand the impacts of atrazine presence to soil-dwelling organisms. To examine this in detail, we used 1 H nuclear magnetic resonance (NMR)-based metabolomics to elucidate earthworm (Eisenia fetida) responses after 48 h of atrazine exposure in contact tests. Earthworms were exposed to 4 sublethal concentrations of 362.4, 181.2, 90.6, and 45.3 ng/cm2 , which correspond to 1/8th, 1/16th, 1/32nd, and 1/64th of the median lethal concentration (LC50) values, respectively. After exposure, polar metabolites were isolated from earthworm tissues and analyzed using 1 H NMR spectroscopy. Sublethal atrazine exposure induced a nonmonotonic response with respect to exposure concentration and caused an overall suppression in earthworm metabolism. Maltose, fumarate, malate, threonine/lactate, adenosine-5'-triphosphate (ATP), betaine, scyllo-inositol, glutamate, arginine, and glutamine were the metabolites identified as most sensitive to atrazine exposure. These observed fluctuations in the metabolic profile suggest that atrazine reduced ATP synthesis and negatively impacted the health of earthworms after acute sublethal exposure. Our study also demonstrates the utility of NMR-based metabolomics for the basic assessment of sublethal toxicity, which can then be used for more targeted approaches with other molecular techniques. Environ Toxicol Chem 2018;37:473-480. © 2017 SETAC.
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Affiliation(s)
- Vivek D Dani
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - André J Simpson
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Myrna J Simpson
- Environmental NMR Centre and Department of Physical Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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Gillis JD, Price GW, Prasher S. Lethal and sub-lethal effects of triclosan toxicity to the earthworm Eisenia fetida assessed through GC-MS metabolomics. JOURNAL OF HAZARDOUS MATERIALS 2017; 323:203-211. [PMID: 27468629 DOI: 10.1016/j.jhazmat.2016.07.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 07/06/2016] [Accepted: 07/07/2016] [Indexed: 06/06/2023]
Abstract
Triclosan (TCS) is a ubiquitous contaminant in municipal biosolids, which has also been detected in soils and earthworms sampled from agricultural fields amended with biosolids. The goal of this study was to evaluate the toxicity of TCS to earthworms using a metabolomics-based approach for an improved interpretation of toxicity. Toxicity of TCS was assessed using the OECD Method 207 filter paper contact test measuring the endpoints of weight loss, mortality, and ten metabolites determined by GC-MS. Eight earthworms were exposed as individual replicates to six concentrations of triclosan (0, 0.0001, 0.001, 0.01, 0.1, and 1mg TCS cm-2) on filter paper, with mortality assessed after 6, 24 and 48h. Mortalities were first observed at 24h, with 100% mortality in the 1 and 0.1mgcm-2 treatments. Worms at 1mgcm-2 lost most of their coelomic fluid before they could be sampled. The 48h LC50 for triclosan was estimated to be 0.006 and 0.008mgcm-2 by a linear and logistic model, respectively. Based on the LC50, triclosan is relatively more toxic to earthworms than a number of other emerging contaminants, but is less toxic than other chlorophenols and many pesticides. Alanine, valine, leucine, serine, phenylalanine, putrescine, spermidine, mannitol, and inositol were significantly different between treatments, although changes were most often associated with mortality rather than triclosan exposure. An increase in putrescine and decrease in amino acids, polyols, and spermidine were associated with mortality, suggesting decomposition had begun. Principal components analysis did not reveal evidence of metabolic impacts at sub-lethal concentrations. However, there were changes in the pattern of correlations between metabolite pairs in surviving worms at both 0.0001 and 0.001mgcm-2 exposure compared to the control.
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Affiliation(s)
- J Daniel Gillis
- Department of Bioresource Engineering, McGill University, Faculty of Agricultural and Environmental Sciences, Macdonald-Stewart Building MS1-027, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Quebec, H9X 3V9, Canada.
| | - Gordon W Price
- Department of Engineering, Dalhousie University, Faculty of Agriculture, 39 Cox Road, PO Box 550, Truro, Nova Scotia, B2N 5E3, Canada
| | - Shiv Prasher
- Department of Bioresource Engineering, McGill University, Faculty of Agricultural and Environmental Sciences, Macdonald-Stewart Building MS1-027, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
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Nirola R, Megharaj M, Venkateswarlu K, Aryal R, Correll R, Naidu R. Assessment of metal toxicity and bioavailability in metallophyte leaf litters and metalliferous soils using Eisenia fetida in a microcosm study. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 129:264-272. [PMID: 27057994 DOI: 10.1016/j.ecoenv.2016.03.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/26/2016] [Accepted: 03/28/2016] [Indexed: 06/05/2023]
Abstract
The leaf litters of tree species, Acacia pycnantha (Ap) and Eucalyptus camaldulensis (Ec), predominantly growing at an abandoned copper (Cu) mine and mine soils including controls, were assessed for determining the metal toxicity and bioavailability using earthworm species Eisenia fetida, in a microcosm. Significant reduction in body weight as well as mortality were observed when the worms were introduced into mine soil or its combination with mine Ap litter. Virtually, there were no juveniles when the worms were fed on substratum that contained mine soil or mine leaf litter. The extent of bioaccumulation was dependent on water-soluble fraction of a metal in soil. The accumulation of cadmium, lead and copper in worm tissue was significantly more in treatments that received mine soil with or without mine leaf litter. However, the tissue concentration of zinc did not differ much in earthworms irrespective of its exposure to control or contaminated samples. Mine leaf litter from Ec, a known Cu hyperaccumulator, was more hospitable to earthworm survival and juvenile than that of Ap litter. Validation of the data on bioaccumulation of metals indicated that the mine leaf litter significantly contributed to metal bioavailability. However, it was primarily the metal concentration in mine soil that was responsible for earthworm toxicity and bioavailability. Our data also indicate that detrivores like earthworm is greatly responsible for heavy metal transfer from mines into the ecosystem.
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Affiliation(s)
- Ramkrishna Nirola
- Future Industries Institute, Division of Information Technology Engineering and the Environment, University of South Australia, SA 5095 Australia.
| | - Mallavarapu Megharaj
- Global Centre for Environmental Research (GCER), University of Newcastle, ATC Building, Callaghan, Newcastle, NSW 2308, Australia
| | - Kadiyala Venkateswarlu
- Formerly Professor of Microbiology & Dean, Faculty of Life Sciences, Sri Krishnadevaraya University, Anantapur 515055, India
| | - Rupak Aryal
- School of Natural and Built Environments, Division of Information Technology Engineering and the Environment, University of South Australia, SA 5095, Australia
| | - Ray Correll
- Future Industries Institute, Division of Information Technology Engineering and the Environment, University of South Australia, SA 5095 Australia
| | - Ravi Naidu
- Global Centre for Environmental Research (GCER), University of Newcastle, ATC Building, Callaghan, Newcastle, NSW 2308, Australia
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Bao Z, Haberer C, Maier U, Beckingham B, Amos RT, Grathwohl P. Modeling long-term uptake and re-volatilization of semi-volatile organic compounds (SVOCs) across the soil-atmosphere interface. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 538:789-801. [PMID: 26340582 DOI: 10.1016/j.scitotenv.2015.08.104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Revised: 07/22/2015] [Accepted: 08/17/2015] [Indexed: 06/05/2023]
Abstract
Soil-atmosphere exchange is important for the environmental fate and atmospheric transport of many semi-volatile organic compounds (SVOCs). This study focuses on modeling the vapor phase exchange of semi-volatile hydrophobic organic pollutants between soil and the atmosphere using the multicomponent reactive transport code MIN3P. MIN3P is typically applied to simulate aqueous and vapor phase transport and reaction processes in the subsurface. We extended the code to also include an atmospheric boundary layer where eddy diffusion takes place. The relevant processes and parameters affecting soil-atmosphere exchange were investigated in several 1-D model scenarios and at various time scales (from years to centuries). Phenanthrene was chosen as a model compound, but results apply for other hydrophobic organic compounds as well. Gaseous phenanthrene was assumed to be constantly supplied to the system during a pollution period and a subsequent regulation period (with a 50% decline in the emission rate). Our results indicate that long-term soil-atmosphere exchange of phenanthrene is controlled by the soil compartment - re-volatilization thus depends on soil properties. A sensitivity analysis showed that accumulation and transport in soils in the short term is dominated by diffusion, whereas in the long term groundwater recharge and biodegradation become relevant. As expected, sorption causes retardation and slows down transport and biodegradation. If atmospheric concentration is reduced (e.g. after environmental regulations), re-volatilization from soil to the atmosphere occurs only for a relatively short time period. Therefore, the model results demonstrate that soils generally are sinks for atmospheric pollutants. The atmospheric boundary layer is only relevant for time scales of less than one month. The extended MIN3P code can also be applied to simulate fluctuating concentrations in the atmosphere, for instance due to temperature changes in the topsoil.
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Affiliation(s)
- Zhongwen Bao
- University of Tübingen, Department of Geosciences, Hölderlinstr. 12, 72074 Tübingen, Germany.
| | - Christina Haberer
- University of Tübingen, Department of Geosciences, Hölderlinstr. 12, 72074 Tübingen, Germany
| | - Uli Maier
- Helmholtz Center for Environmental Research - UFZ, Department of Hydrogeology, Permoserstr. 15, 04318 Leipzig, Germany
| | - Barbara Beckingham
- College of Charleston, Department of Geology and Environmental Geosciences, 202 Calhoun Street, 29401 Charleston, SC, United States
| | - Richard T Amos
- Carleton University, Department of Earth Sciences, 1125 Colonel By Drive, K1S 5B6 Ottawa, ON, Canada
| | - Peter Grathwohl
- University of Tübingen, Department of Geosciences, Hölderlinstr. 12, 72074 Tübingen, Germany
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Ferreira RCB, Papini S, de Andréa MM. Bioavailability and influence of ¹⁴C-carbofuran on Eisenia andrei avoidance, growth and reproduction in treated natural tropical soils. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2015; 50:266-274. [PMID: 25714458 DOI: 10.1080/03601234.2015.999599] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The bioavailability of carbofuran to the compost worms Eisenia andrei and the influence of its residual amounts on the avoidance, reproduction and growth of this species were studied in two natural tropical soils: a Typic Humaquept (GM) and a Typic Hapludox (LVD), as indicated by the Brazilian environmental authorities for ecotoxicological tests. The worms avoided the soil LVD treated with different doses of carbofuran. The pesticide also affected the production of juvenile specimens in both soils, but cocoon production was reduced only in the GM soil. The earthworms' growth and weight loss were affected by carbofuran (2,2-dimethyl-2,3-dihydro-1-1-benzofuran-7-yl methylcarbamate. CAS number 1563-66-2) only in the LVD and the mortality detected at 56 days of contact with the treated soils was not statistically significant in both of them. Fourteen days after the soil treatment with(14) c-carbofuran, most residues detected in the soils were bound residues (approximately 36% and 30% in the GM and LVD, respectively) and neither mortality nor bioaccumulation was detected in the earthworms, even with absorptions of 13% and 43%, respectively. The LVD soil has lower organic matter content, and the effects of carbofuran on different aspects of the earthworms' life were more pronounced in this soil, most likely due to the higher bioavailability of the pesticide in the soil solution. The results for carbofuran clearly demonstrate that even small quantities of residues do not assure lack of toxicity. They also make evident the necessity of studying the effects of pesticides in natural agricultural soils. Furthermore, as the bound residues and the earthworm contamination are not detected by conventional techniques, they are not taken into account and may be underestimated on environmental risk assessments.
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Affiliation(s)
- Regina C B Ferreira
- a Laboratory of Agrochemical Ecology, Biological Institute , São Paulo , Brazil
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