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Li D, Chang F, Zhang Y, Duan L, Liu Q, Li H, Hu G, Zhang X, Gao Y, Zhang H. Arsenic migration at the sediment-water interface of anthropogenically polluted Lake Yangzong, Southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:163205. [PMID: 37004769 DOI: 10.1016/j.scitotenv.2023.163205] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/26/2023] [Accepted: 03/28/2023] [Indexed: 05/17/2023]
Abstract
The lability and controlling factors of arsenic (As) at the sediment-water interface (SWI) are crucial for understanding As behaviors and fates in As-contaminated areas. In this study, we combined high-resolution (5 mm) sampling using diffusive gradients in thin films (DGT) and equilibrium dialysis sampling (HR-Peeper), sequential extraction (BCR), fluorescence signatures, and fluorescence excitation-emission matrices (EEMs)-parallel factor analysis (PARAFAC) to explore the complex mechanisms of As migration in a typical artificially polluted lake, Lake Yangzong (YZ). The study results showed that a high proportion of the reactive As fractions in sediments can resupply pore water in soluble forms during the change from the dry season (winter, oxidizing period) to the rainy season (summer, reductive period). In dry season, the copresence of Fe oxide-As and organic matter (OM)-As complexes was related to the high dissolved As concentration in pore water and limited exchange between the pore water and overlying water. In the rainy season, with the change in redox conditions, the reduction of Fe-Mn oxides and OM degradation by microorganisms resulted in As deposition and exchange with the overlying water. Partial least squares path modelling (PLS-PM) indicated that OM affected the redox and As migration processes through degradation. Based on comprehensive analyses of the As, Fe, Mn, S and OM levels at the SWI, we suggest that the complexation and desorption of dissolved organic matter and Fe oxides play an important role in As cycling. Our findings shed new light on the cascading drivers of As migration and OM features in seasonal lakes and constitute a valuable reference for scenarios with similar conditions.
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Affiliation(s)
- Donglin Li
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Fengqin Chang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China.
| | - Yang Zhang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Lizeng Duan
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Qi Liu
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Haoyu Li
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Guangzhi Hu
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Xiaonan Zhang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Youhong Gao
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China
| | - Hucai Zhang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650504, Yunnan, China; Southwest United Graduate School, Kunming 650500, Yunnan, China.
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Zhao Y, Chen YP. Coming ecological risks of organochlorine pesticides and novel brominated flame retardants in the Yellow River Basin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159296. [PMID: 36216067 DOI: 10.1016/j.scitotenv.2022.159296] [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: 08/10/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
To conduct ecological risk assessment, food, water and soil samples were collected from five densely populated irrigation areas in the Yellow River Basin (YRB), and analyzed for organochlorine pesticides (OCPs) and novel brominated flame retardants (NBFRs). The results showed that the OCP residues (∑14OCP were 0.748 ng L-1, 13.1 ng g-1 dw and 3.22 ng g-1 dw in water, soil and maize) were generally within moderate levels in the YRB. Dichlorodiphenyltrichloroethane (DDT) residues dominated the OCPs, and potential ecological risks to aquatic and terrestrial organisms likely stemmed from dichlorodiphenyldichloroethylene (DDE) pollution in the upper reaches of the YRB in the Ningxia and Hetao Plain. The NBFR concentrations in the YRB were 90.9 pg L-1 in water, 21.1 pg g-1 dw in soil and 3.81 pg g-1 dw in maize. Positive correlations were observed between soil and maize contamination in the five irrigated districts, indicating a potential threat to grain security and human health risks caused by OCPs and NBFRs. Pollutants detected in soil and maize primarily originated from historical use (36.3 %), while the sources in water were more complex (64.4 %) and new inputs could not be excluded. Integrated health risks of human exposure to agricultural products and water from the YRB were acceptable. However, the ecological risk of the Ningxia Plain would further deteriorate to the medium risk after 2032. The increasing ecological risk of DDT in water indicates that regular monitoring should strengthen to ensure grain and water safety in the YRB.
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Affiliation(s)
- Yan Zhao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS, Xi'an 710061, China
| | - Yi-Ping Chen
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS, Xi'an 710061, China.
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Zhang X, Wang B, Pan F, Cai Y, Wu X, Liu H, Guo Z. Potential pollution assessment of labile trace metals in Xixi River estuary sediments in Xiamen, China. JOURNAL OF CONTAMINANT HYDROLOGY 2022; 250:104055. [PMID: 35917655 DOI: 10.1016/j.jconhyd.2022.104055] [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: 11/29/2021] [Revised: 06/03/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
The release of trace metals caused by industrial effluents and anthropogenic activities has been recorded in the Xixi River estuary, southern China. However, a thorough understanding of the behavior of trace heavy metals in Xixi River sediments is lacking. A total of 12 sediment cores were collected in June and December in the upper estuary section and mouth of the estuary. Here, an in situ high-resolution sampling technique, namely, diffusive gradients in thin films (DGT), was employed to acquire profiles of trace element concentrations and the release of bioavailable metals from sediments in different seasons. A three-step Community Bureau of Reference (BCR) sequential extraction method was used to explore the chemical speciation of trace metals in different seasons and to thereby assess the release potential of trace elements in sediments. The BCR sequential extraction results showed that the trace metals Fe, Mn, Co and Pb were mainly in the residual fraction, which rarely influences living organisms. The total mobile fractions (F1 + F2 + F3) of all trace metals were higher in winter than in summer, suggesting that accumulation occurred from summer to winter. DGT measurements showed that the intensity of sulfate reduction was higher in summer than in winter because of the high temperatures and high organic matter in summer. The intensity of sulfate and Mn(III/IV) reduction increased from the upper estuary section to the lower estuary. Fe(III) reduction decreased in summer but increased slowly in winter. The Pearson correlation results showed that the release of DGT-labile Co in pore water was related to Mn(III/IV) reduction, while the release of DGT-labile Pb was basically not controlled by the Fe-Mn-S redox transition. Abnormally high DGT-labile Pb concentrations were observed at the sampling station (XR3) closest to the estuary in winter, which might have been caused by the high Pb content in the local micro-sediments.
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Affiliation(s)
- Xiaoting Zhang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Bo Wang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Feng Pan
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China
| | - Yu Cai
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Xindi Wu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Huatai Liu
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China.
| | - Zhanrong Guo
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China.
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Pan F, Xiao K, Guo Z, Li H. Effects of fiddler crab bioturbation on the geochemical migration and bioavailability of heavy metals in coastal wetlands. JOURNAL OF HAZARDOUS MATERIALS 2022; 437:129380. [PMID: 35897186 DOI: 10.1016/j.jhazmat.2022.129380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/31/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Fiddler crabs, found in coastal wetlands worldwide, function as ecosystem engineers. Their burrowing activity can significantly alter biogeochemistry at the local scale, however, the mobility of heavy metals (HMs) in burrow sediments remains unclear. Here, we used diffusive gradients in thin-film probes to obtain bioavailable Fe and HMs (Cu, Zn, Ni, Cd, Pb, Co, and Mo) in crab burrows from coastal wetlands (mudflats, salt marshes, and mangroves). The depth-profile results showed that most HMs were enriched at shallow and deep depths but deficient at middle depths. We highlighted that bioturbation improved oxic conditions, enhanced HM concentrations, and favored dissolved HM retention in burrow sediments, which served as a sink for overlying water HMs via burrow flushing but a potential source of particle HMs via enhanced resuspension. In deep anoxic layers, Fe(III) reduction drove the remobilization of HMs, except Cu and Mo, leading to the co-release of HMs with Fe. This Fe-HM coupling/decoupling was verified using enhanced two-dimensional high-resolution imaging, which revealed highly spatial heterogeneity of multiple HMs. Moreover, the hydrological conditions regulating bioturbation effects on HM behavior varied across different coastal wetlands. With coastal environmental changes, the key role of ubiquitous bioturbation in HM migration and bioavailability should be reconsidered.
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Affiliation(s)
- Feng Pan
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Kai Xiao
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, PR China.
| | - Zhanrong Guo
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Hailong Li
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, PR China
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Pan F, Cai Y, Guo Z, Fu Y, Wu X, Liu H, Wang X. Kinetic characteristics of mobile Mo associated with Mn, Fe and S redox geochemistry in estuarine sediments. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126200. [PMID: 34111753 DOI: 10.1016/j.jhazmat.2021.126200] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 05/15/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Estuarine sediments are crucial repositories and incubators of molybdenum (Mo) during its transport from rivers to the ocean. Here, Mo mobility and related processes in estuarine sediments were explored using high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) techniques. Better correlations were observed between dissolved Mn and Mo than between dissolved Fe and Mo, implying that Mn geochemistry plays a key role in dissolved Mo mobility via molybdate adsorption onto abundant Mn oxides and its substantial release upon intense Mn reduction. As a result, oxic intertidal sediments functioned as Mo sinks, and anoxic subtidal sediments functioned as Mo sources. The opposite vertical distributions between DGT-Labile S and DGT-Labile Mo indicated that the availability of labile Mo can be blocked by aqueous sulfide. However, the corresponding high concentrations of DGT-Labile S and dissolved Mo at subtidal sites demonstrated that the abundant dissolved Mo remobilized via Mn reduction was not effectively solidified by sulfide. Simulation with the DIFS model further verified that redox conditions and induced physicochemical processes are crucial factors controlling Mo mobility, with relatively low dissolved Mo concentrations but an adequate and steady resupply capacity of the bioavailable molybdate in intertidal sediments.
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Affiliation(s)
- Feng Pan
- College of the Environment & Ecology, Xiamen University, Xiamen 361102, PR China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, PR China.
| | - Yu Cai
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Zhanrong Guo
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China.
| | - Yuyao Fu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Xindi Wu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Huatai Liu
- College of the Environment & Ecology, Xiamen University, Xiamen 361102, PR China.
| | - Xinhong Wang
- College of the Environment & Ecology, Xiamen University, Xiamen 361102, PR China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, PR China
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