1
|
Mehlhorn P, Humphries M, Gensel J, Buah-Kwofie A, Tyohemba RL, Haberzettl T. Organochlorine pesticide contamination in sediments from Richards Bay, South Africa: spatial trends and ecotoxicological risks. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:2247-2259. [PMID: 35931841 PMCID: PMC9813156 DOI: 10.1007/s11356-022-22298-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 07/25/2022] [Indexed: 05/19/2023]
Abstract
The occurrence and distribution of organochlorine pesticides (OCPs) in aquatic systems is a matter of global concern and poses significant toxicological threats to both organisms and human health. Despite the extensive use of OCPs for pest and disease control in southern Africa, relatively few studies have examined the occurrence and toxicological risks of OCP residues in the region. This study investigates the composition, distribution, and potential sources of OCP contamination in sediments from Richards Bay, a rapidly developing industrial port on the northeast coast of South Africa. Surface sediments collected from Richards Bay Harbour and surrounding areas indicate that OCP contamination in the region is widespread. Total concentrations (∑OCP) in surface samples ranged from 135 to 1020 ng g-1, with hexachlorocyclohexanes (∑HCH; 35-230 ng g-1) and dichlorodiphenyltrichloroethanes (∑DDT; 12-350 ng g-1) the dominant contaminant groups detected. Metabolite isomeric compositions indicate that the presence of aldrin and endosulfan likely result from historical agricultural usage, while recent input of γ-HCH, heptachlor, and endrin may be linked to the illegal use of old pesticide stockpiles. Total DDT concentrations were dominated by p,p'-DDT (80 ± 64 ng g-1), which was attributed to its ongoing use in malaria vector control in the region. A 210Pb-dated sediment core revealed that OCP input to the local environment increased dramatically from relatively low concentrations in the mid-1940s (∑OCP, 355 ng g-1) to peak levels (∑OCP, 781 ng g-1) in the 1980s/1990s. An overall decrease in ∑OCP concentration from the mid-2000s is likely related to restrictions on use following the Stockholm Convention in 2004. Despite current restrictions on use, OCP concentrations exceeded sediment quality guidelines in the vast majority of cases, raising concerns for protected estuarine and mangrove habitats in the area, as well as for local fishing and farming communities.
Collapse
Affiliation(s)
- Paul Mehlhorn
- Institute for Geography and Geology, University of Greifswald, F.L.-Jahn Str. 16, 17489, Greifswald, Germany.
| | - Marc Humphries
- School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa
| | - Julia Gensel
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Archibold Buah-Kwofie
- School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa
- Nuclear Power Institute, Ghana Atomic Energy Commission, P. O Box LG 80, Legon, Accra, Ghana
| | | | - Torsten Haberzettl
- Institute for Geography and Geology, University of Greifswald, F.L.-Jahn Str. 16, 17489, Greifswald, Germany
| |
Collapse
|
2
|
Kock A, Smit NJ, Taylor JC, Wolmarans NJ, Wepener V. A lentic microcosm approach to determine the toxicity of DDT and deltamethrin on diatom communities. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 312:120037. [PMID: 36030961 DOI: 10.1016/j.envpol.2022.120037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 08/16/2022] [Accepted: 08/20/2022] [Indexed: 06/15/2023]
Abstract
Worldwide the use of pesticides has increased, especially in the industry and agriculture sector even though they contain highly toxic substances. The use of pesticides has various negative effects on the aquatic ecosystem and organisms within these ecosystems. The paper aimed to assess the effects of increased concentrations of malaria vector control insecticides (Dichlorodiphenyltrichloroethane (DDT) and Deltamethrin (DTM)) on the freshwater diatom community structure using a microcosm approach as well as determine whether a mixture (DDT 1:1 Deltamethrin) exposure will have a greater influence on the diatom community when compared to single exposures of these insecticides. Diatoms were exposed to a high and low concentration (based on LC50 data for freshwater Xenopus laevis from the USEPA Ecotox database) of DDT, DTM and a mixture in lentic microcosms over a total period of 28 days. Results indicated that irrespective of exposure concentrations, DDT, DTM and a mixture had negative effects on the diatom community including functionality and vitality as these insecticides induced changes to their chloroplasts. There was an increased percentage dead cells for all exposures compared to the control, with the insecticides having a phototoxic effect on the diatom community. Exposure to the selected insecticides caused a significant decrease in some diatom metrics indicating the negative effects these insecticides have on the diatom metrics. Therefore, diatoms may prove to be useful as bio-indicators in ecotoxicology studies when assessing the effects of any insecticide exposures.
Collapse
Affiliation(s)
- Anrich Kock
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
| | - Nico J Smit
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - Jonathan C Taylor
- Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa; South African Institute for Aquatic Biodiversity (SAIAB), Private Bag 1015, Grahamstown, 6140, South Africa
| | - Nico J Wolmarans
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa; Laboratory of Systemic, Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Victor Wepener
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| |
Collapse
|
3
|
Horak I, Horn S, Pieters R. Agrochemicals in freshwater systems and their potential as endocrine disrupting chemicals: A South African context. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115718. [PMID: 33035912 PMCID: PMC7513804 DOI: 10.1016/j.envpol.2020.115718] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 05/28/2023]
Abstract
South Africa is the largest agrochemical user in sub-Saharan Africa, with over 3000 registered pesticide products. Although they reduce crop losses, these chemicals reach non-target aquatic environments via leaching, spray drift or run-off. In this review, attention is paid to legacy and current-use pesticides reported in literature for the freshwater environment of South Africa and to the extent these are linked to endocrine disruption. Although banned, residues of many legacy organochlorine pesticides (endosulfan and dichlorodiphenyltrichloroethane (DDT)) are still detected in South African watercourses and wildlife. Several current-use pesticides (triazine herbicides, glyphosate-based herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and chlorpyrifos) have also been reported. Agrochemicals can interfere with normal hormone function of non-target organism leading to various endocrine disrupting (ED) effects: intersex, reduced spermatogenesis, asymmetric urogenital papillae, testicular lesions and infertile eggs. Although studies investigating the occurrence of agrochemicals and/or ED effects in freshwater aquatic environments in South Africa have increased, few studies determined both the levels of agricultural pesticides present and associated ED effects. The majority of studies conducted are either laboratory-based employing in vitro or in vivo bioassays to determine ED effects of agrochemicals or studies that investigate environmental concentrations of pesticides. However, a combined approach of bioassays and chemical screening will provide a more comprehensive overview of agrochemical pollution of water systems in South Africa and the risks associated with long-term chronic exposure.
Collapse
Affiliation(s)
- Ilzé Horak
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.
| | - Suranie Horn
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Rialet Pieters
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| |
Collapse
|
4
|
Rose NL, Milner AM, Fitchett JM, Langerman KE, Yang H, Turner SD, Jourdan AL, Shilland J, Martins CC, de Souza AC, Curtis CJ. Natural archives of long-range transported contamination at the remote lake Letšeng-la Letsie, Maloti Mountains, Lesotho. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 737:139642. [PMID: 32546308 DOI: 10.1016/j.scitotenv.2020.139642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
Naturally accumulating archives, such as lake sediments and wetland peats, in remote areas may be used to identify the scale and rates of atmospherically deposited pollutant inputs to natural ecosystems. Co-located lake sediment and wetland cores were collected from Letšeng-la Letsie, a remote lake in the Maloti Mountains of southern Lesotho. The cores were radiometrically dated and analysed for a suite of contaminants including trace metals and metalloids (Hg, Pb, Cu, Ni, Zn, As), fly-ash particles, stable nitrogen isotopes, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants such as polychlorinated biphenyls (PCBs), polybrominated flame retardants (PBDEs) and hexachlorobenzene (HCB). While most trace metals showed no recent enrichment, mercury, fly-ash particles, high molecular weight PAHs and total PCBs showed low but increasing levels of contamination since c.1970, likely the result of long-range transport from coal combustion and other industrial sources in the Highveld region of South Africa. However, back-trajectory analysis revealed that atmospheric transport from this region to southern Lesotho is infrequent and the scale of contamination is low. To our knowledge, these data represent the first palaeolimnological records and the first trace contaminant data for Lesotho, and one of the first multi-pollutant historical records for southern Africa. They therefore provide a baseline for future regional assessments in the context of continued coal combustion in South Africa through to the mid-21st century.
Collapse
Affiliation(s)
- Neil L Rose
- Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London WC1E 6BT, UK.
| | - Alice M Milner
- Department of Geography, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Jennifer M Fitchett
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, 2050, South Africa
| | - Kristy E Langerman
- Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, Corner Ditton and University Avenue, Auckland Park, Johannesburg, South Africa
| | - Handong Yang
- Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London WC1E 6BT, UK
| | - Simon D Turner
- Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London WC1E 6BT, UK
| | - Anne-Lise Jourdan
- Bloomsbury Environmental Isotope Facility, Department of Earth Sciences, University College London, Gower Street, London WC1E 6BS, UK
| | - James Shilland
- Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London WC1E 6BT, UK
| | - César C Martins
- Centro de Estudos do Mar da Universidade Federal do Paraná, Caixa Postal 61, 83255-976 Pontal do Paraná, PR, Brazil
| | - Amanda Câmara de Souza
- Centro de Estudos do Mar da Universidade Federal do Paraná, Caixa Postal 61, 83255-976 Pontal do Paraná, PR, Brazil
| | - Christopher J Curtis
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, 2050, South Africa; Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, Corner Ditton and University Avenue, Auckland Park, Johannesburg, South Africa
| |
Collapse
|
5
|
Bouwman H, Yohannes YB, Nakayama SMM, Motohira K, Ishizuka M, Humphries MS, van der Schyff V, du Preez M, Dinkelmann A, Ikenaka Y. Evidence of impacts from DDT in pelican, cormorant, stork, and egret eggs from KwaZulu-Natal, South Africa. CHEMOSPHERE 2019; 225:647-658. [PMID: 30901658 DOI: 10.1016/j.chemosphere.2019.03.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 06/09/2023]
Abstract
DDT remains in use for malaria control in South Africa. We quantified DDTs in aquatic bird eggs from the highly biodiverse northern KwaZulu-Natal, a province of South Africa where DDT has been used for more than 80 years for malaria control. Pelican eggs had the highest ΣDDT concentration (7200 ng/g lipid mass; lm), Little Egret eggs had 6900 ΣDDT lm, African Openbill eggs had 3400 ng/g lm ΣDDT, and White-breasted Cormorant had 2400 ng/g lm. All species had non-significantly different mean concentrations of o,p'-DDT, p,p'-DDT, and ΣDDT, but with significant differences for p,p-DDE, o,p'-DDD, p,p'-DDD, %DDT, %DDD, and %lipid. The thinnest pelican eggshell (0.40 mm) had a ΣDDT concentration of 3300 ng/g lm.; the thickest shell (0.96 mm) had the lowest ΣDDT concentration at 29 ng/g lm; a 58% difference. Linear regressions of concentrations with shell thickness for the pelican eggs were significant for p,p'-DDE and p,p'-DDD, indicating risk of reproductive impairment. Compositional profiles indicate different food webs for the different species. DDT concentrations were lower than from another DDT-sprayed locality in South Africa, possible linked to differences in hydrology and rainfall. We conclude that significant ecotoxic threats associated with DDT remain in this area, and possibly threatens birds from less polluted areas. Our findings suggest continued negative human health and environmental impacts from DDT. There is an urgency to move away from DDT as quickly as possible; alternatively, to implement practices that prevent emissions of DDT to the environment while protecting human life.
Collapse
Affiliation(s)
- H Bouwman
- Research Unit, Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa.
| | - Y B Yohannes
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan; Department of Chemistry, College of Natural and Computational Science, University of Gondar, Gondar, Ethiopia
| | - S M M Nakayama
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - K Motohira
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - M Ishizuka
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - M S Humphries
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa
| | - V van der Schyff
- Research Unit, Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa
| | - M du Preez
- Research Unit, Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa
| | - A Dinkelmann
- Research Unit, Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa
| | - Y Ikenaka
- Research Unit, Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa; Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| |
Collapse
|
6
|
Porter SN, Humphries MS, Buah-Kwofie A, Schleyer MH. Accumulation of organochlorine pesticides in reef organisms from marginal coral reefs in South Africa and links with coastal groundwater. MARINE POLLUTION BULLETIN 2018; 137:295-305. [PMID: 30503438 DOI: 10.1016/j.marpolbul.2018.10.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 10/10/2018] [Accepted: 10/12/2018] [Indexed: 06/09/2023]
Abstract
Coral reefs support rich levels of biodiversity, but are globally threatened by a multitude of factors, including land-sourced pollutants. Concentrations of organochlorine pesticides (OCPs) in three species of coral reef invertebrate at five sites along the Maputaland coast, South Africa were quantified. We aimed to assess spatial and interspecies variations in pesticide accumulation. Markedly high levels of a range of OCP residues were detected within tissues, with total concentrations (ng g-1 ww) ranging from 460 to 1200 (Sarcophyton glaucum), 1100-3000 (Sinularia gravis) and 450-1500 (Theonella swinhoei), respectively. A decreasing gradient in total pesticide concentrations was detected southward from Regal Reef, opposite Lake Sibaya, the hypothesised source of the pollutants. Observed gradients in pesticide concentrations and nitrogen isotope signatures indicated coastal groundwater to be the likely source of the pollutants. Further studies are required to assess the potential ecotoxicological impacts of these contaminants at the organismal and ecosystem level.
Collapse
Affiliation(s)
- Sean N Porter
- Oceanographic Research Institute, PO Box 10712, Marine Parade, Durban 4056, South Africa.
| | - Marc S Humphries
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050, South Africa
| | - Archibold Buah-Kwofie
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050, South Africa
| | - Michael H Schleyer
- Oceanographic Research Institute, PO Box 10712, Marine Parade, Durban 4056, South Africa
| |
Collapse
|
7
|
Buah-Kwofie A, Humphries MS, Pillay L. Bioaccumulation and risk assessment of organochlorine pesticides in fish from a global biodiversity hotspot: iSimangaliso Wetland Park, South Africa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 621:273-281. [PMID: 29186702 DOI: 10.1016/j.scitotenv.2017.11.212] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/18/2017] [Accepted: 11/18/2017] [Indexed: 06/07/2023]
Abstract
UNLABELLED Organochlorine pesticides (OCPs) have been used extensively in the eastern regions of South Africa for agricultural and malaria control purposes, yet few data exist on the local environmental and social impacts of these compounds. Such issues have become of increasing concern in the iSimangaliso World Heritage Site, where the continued use of OCPs may pose risks to several sensitive and protected species. This study was designed to examine the bioaccumulation of OCPs in two common fish species, Oreochromis mossambicus (Mozambique tilapia) and Clarias gariepinus (African sharptooth catfish) from iSimangaliso Wetland Park. These species are targeted by local subsistence fishermen and sustain substantial bird and crocodile populations. Our findings indicate widespread contamination of the aquatic environment, with ΣOCP fish tissue concentrations in the range of 6907-8740ngg-1 lw and 2953-5874ngg-1 lw for C. gariepinus and O. mossambicus, respectively. HCHs (471-1570ngg-1 lw), DDTs (645-2399ngg-1 lw), drin-related residues (589-1960ngg-1 lw), chlor-related residues (455-2162ngg-1 lw) and endosulfans (457-1495ngg-1 lw) were detected in all tissue samples. Concentrations detected in the majority of samples exceeded European Commission maximum residue limits and a health risk assessment indicated potential dietary risk associated with exposure to heptachlor, heptachlor epoxide and dieldrin. This study represents the first investigation into OCP bioaccumulation in fish species from iSimangaliso Wetland Park. Our findings highlight the need for more detailed investigations into the bioaccumulation and ecotoxicological effects of these contaminants in the food web and the associated risks to local ecosystems and human health. CAPSULE High levels of OCPs detected in two common fish species at iSimangaliso Wetland Park highlight potential human health and ecotoxicological threats to a globally important biodiversity conservation hotspot.
Collapse
Affiliation(s)
- Archibold Buah-Kwofie
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa.
| | - Marc S Humphries
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa
| | - Letitia Pillay
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa
| |
Collapse
|
8
|
Buah-Kwofie A, Humphries MS. The distribution of organochlorine pesticides in sediments from iSimangaliso Wetland Park: Ecological risks and implications for conservation in a biodiversity hotspot. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 229:715-723. [PMID: 28728131 DOI: 10.1016/j.envpol.2017.07.031] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/16/2017] [Accepted: 07/11/2017] [Indexed: 06/07/2023]
Abstract
The iSimangaliso Wetland Park World Heritage site, located on the east coast of South Africa, spans ∼3300 km2 and constitutes the largest protected estuarine environment for hippopotami, crocodiles and aquatic birds in Africa. Given the ecological importance of this site and continued use of organochlorine pesticides (OCPs) in the region, this study focused on the nature, distribution and potential sources of organochlorine contamination within iSimangaliso Wetland Park. OCPs were widely distributed in surface sediment samples obtained from the four main Ramsar wetland systems within the park (Lake St Lucia, Mkhuze, Lake Sibaya and Kosi Bay). ∑HCH and ∑DDT were the dominant contaminants detected with concentrations in the range of 26.29-282.5 ng/g and 34.49-262.4 ng/g, respectively. ∑DDT concentrations revealed a distinctive gradient, with significantly higher concentrations at Kosi Bay and Lake Sibaya attributed to the application of DDT for malaria control. p,p'-DDE and p,p'-DDD were the dominant isomers detected, but the detection of p,p'-DDT in a number of samples reflects recent inputs of technical DDT. Highest concentrations of HCH, endosulfan and heptachlor were detected in sediments from Mkhuze and reflect the substantial residue load these wetlands receive from agricultural activities within the catchment area. Isomeric compositions indicate that endosulfan and heptachlor residues are derived mainly from historical application, while inputs of HCH, aldrin and endrin could be attributed to more recent usage at several sites. OCP sediment concentrations from iSimangaliso represent the highest yet recorded in South Africa and some of the highest reported globally this century. Sediments found within the lakes and wetlands of iSimangaliso represent large reservoirs of contaminants that pose ecotoxicological threats to this globally important biodiversity hotspot. Detailed investigation into the bioaccumulation and toxicological risks of OCPs within the wetland park is urgently required.
Collapse
Affiliation(s)
- Archibold Buah-Kwofie
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa.
| | - Marc S Humphries
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa
| |
Collapse
|
9
|
Mendez A, Ng CA, Torres JPM, Bastos W, Bogdal C, Dos Reis GA, Hungerbuehler K. Modeling the dynamics of DDT in a remote tropical floodplain: indications of post-ban use? ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:10317-10334. [PMID: 26503006 DOI: 10.1007/s11356-015-5641-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/18/2015] [Indexed: 06/05/2023]
Abstract
Significant knowledge gaps exist regarding the fate and transport of persistent organic pollutants like dichlorodiphenyltrichloroethane (DDT) in tropical environments. In Brazil, indoor residual spraying with DDT to combat malaria and leishmaniasis began in the 1950s and was banned in 1998. Nonetheless, high concentrations of DDT and its metabolites were recently detected in human breast milk in the community of Lake Puruzinho in the Brazilian Amazon. In this work, we couple analysis of soils and sediments from 2005 to 2014 at Puruzinho with a novel dynamic floodplain model to investigate the movement and distribution of DDT and its transformation products (dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD)) and implications for human exposure. The model results are in good agreement with the accumulation pattern observed in the measurements, in which DDT, DDE, and DDD (collectively, DDX) accumulate primarily in upland soils and sediments. However, a significant increase was observed in DDX concentrations in soil samples from 2005 to 2014, coupled with a decrease of DDT/DDE ratios, which do not agree with model results assuming a post-ban regime. These observations strongly suggest recent use. We used the model to investigate possible re-emissions after the ban through two scenarios: one assuming DDT use for IRS and the other assuming use against termites and leishmaniasis. Median DDX concentrations and p,p'-DDT/p,p'-DDE ratios from both of these scenarios agreed with measurements in soils, suggesting that the soil parameterization in our model was appropriate. Measured DDX concentrations in sediments were between the two re-emission scenarios. Therefore, both soil and sediment comparisons suggest re-emissions indeed occurred between 2005 and 2014, but additional measurements would be needed to better understand the actual re-emission patterns. Monte Carlo analysis revealed model predictions for sediments were very sensitive to highly uncertain parameters associated with DDT degradation and partitioning. With this model as a tool for understanding inter-media cycling, additional research to refine these parameters would improve our understanding of DDX fate and transport in tropical sediments.
Collapse
Affiliation(s)
- Annelle Mendez
- Institute for Chemical and Bioengineering, ETH Zurich, CH-8093, Zürich, Switzerland
| | - Carla A Ng
- Institute for Chemical and Bioengineering, ETH Zurich, CH-8093, Zürich, Switzerland.
| | | | - Wanderley Bastos
- Department of Biology, Federal University of Rondônia, Porto Velho, Brazil
| | - Christian Bogdal
- Institute for Chemical and Bioengineering, ETH Zurich, CH-8093, Zürich, Switzerland
- Agroscope, Institute for Sustainability Sciences ISS, CH-8046, Zürich, Switzerland
| | | | - Konrad Hungerbuehler
- Institute for Chemical and Bioengineering, ETH Zurich, CH-8093, Zürich, Switzerland
| |
Collapse
|
10
|
Jin X, Wang F, Gu C, Yang X, Kengara FO, Bian Y, Song Y, Jiang X. The interactive biotic and abiotic processes of DDT transformation under dissimilatory iron-reducing conditions. CHEMOSPHERE 2015; 138:18-24. [PMID: 26025430 DOI: 10.1016/j.chemosphere.2015.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 05/04/2015] [Accepted: 05/10/2015] [Indexed: 06/04/2023]
Abstract
The objective of the study was to elucidate the biotic and abiotic processes under dissimilatory iron reducing conditions involved in reductive dechlorination and iron reduction. DDT transformation was investigated in cultures of Shewanella putrefaciens 200 with/without α-FeOOH. A modified first-order kinetics model was developed and described DDT transformation well. Both the α-FeOOH reduction rate and the dechlorination rate of DDT were positively correlated to the biomass. Addition of α-FeOOH enhanced reductive dechlorination of DDT by favoring the cell survival and generating Fe(II) which was absorbed on the surface of bacteria and iron oxide. 92% of the absorbed Fe(II) was Na-acetate (1M) extractable. However, α-FeOOH also played a negative role of competing for electrons as reflected by the dechlorination rate of DDT was inhibited when increasing the α-FeOOH from 1 g L(-1) to 5 g L(-1). DDT was measured to be toxic to S. putrefaciens 200. The metabolites DDD, DDE and DDMU were recalcitrant to S. putrefaciens 200. The results suggested that iron oxide was not the key factor to promote the dissipation of DDX (DDT and the metabolites), whereas the one-electron reduction potential (E1) of certain organochlorines is the main factor and that the E1 higher than the threshold of the reductive driving forces of DIRB probably ensures the occur of reductive dechlorination.
Collapse
Affiliation(s)
- Xin Jin
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Fang Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Chenggang Gu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xinglun Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | | | - Yongrong Bian
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yang Song
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xin Jiang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| |
Collapse
|
11
|
Species composition, distribution and habitat types of Odonata in the iSimangaliso Wetland Park, KwaZulu-Natal, South Africa and the associated conservation implications. PLoS One 2014; 9:e92588. [PMID: 24662948 PMCID: PMC3963920 DOI: 10.1371/journal.pone.0092588] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/23/2014] [Indexed: 11/19/2022] Open
Abstract
Maputaland–Pondoland–Albany, South Africa has been identified as a biodiversity hotspot and centre for endemism. Odonata make good indicators of freshwater ecosystem health. Consequently we compiled a list of Odonata species recorded to date in the iSimangaliso Wetland Park. We then detailed important species in terms of endemism, conservation status, and potential as indicator species. Finally, we compared Odonata assemblages of different sites sampled within the park to illustrate habitat importance. Species identified during two formal surveys and incidental observations made during the study period were combined with an existing database to compile an accurate and up to date species list for the iSimangaliso Wetland Park. Data from this study were then analyzed to determine which water bodies had the most similar species composition. The Dragonfly Biotic Index (DBI) value of each study area was also determined. We recorded 68 odonate species in the iSimangaliso Wetland Park, adding 13 species to the Ezemvelo KwaZulu-Natal Wildlife database for the area. This brings the total number of Odonata species for the iSimangaliso Wetland Park to 86. Eight species are red-listed, 12 are restricted in South Africa to the coastal plains of northern KwaZulu-Natal, and the remainder occurs widely across the southern African savanna. Analyses indicate that species odonate assemblages were most similar in water bodies with comparable habitats. iSimangaliso Wetland Park is identified as an important area for Odonata diversity and endemism, a trend also reflected by the DBI values. Shifts in the existing species assemblages would indicate changes within the ecosystem and thus this species account provides necessary baseline data for the area. Species Conservation efforts should thus target water bodies of varying habitat types to protect greater species diversity.
Collapse
|