Search

Contamination by neonicotinoid (NEO) insecticides in surface waters is a global problem. Nevertheless, the occurrence of NEOs in lakes is not well known. Hongze Lake, the largest impounded lake on the Eastern Route of the South-to-North Water Diversion Project, was selected to investigate the distribution, ecological risks, and health risks of NEOs. Water samples from the lake and nearby rivers were collected and analyzed for 8 widely used NEOs in three seasons. The results indicated the average total NEO concentration in summer, winter, and spring was 222, 211, and 244 ng L -1 for the river water, and 265, 213, and 181 ng L -1 for the lake water, respectively, with no statistical seasonal difference. For the river water, the highest total NEO concentration in the three seasons was observed in the Andong River. For the lake water, the total NEO concentrations in summer were relatively high in sites near the inflow river estuaries due to the high riverine inputs during the flood period. The spatial difference in NEO concentration was relatively low in winter, which may be related to the wind-driven lake current. The seasonal variation in NEO compositions in the lake was generally similar to that in the river, indicating riverine input was the important source for the lake. Huai River was the largest contributor to the NEO inputs to the lake, and Sanhe Gate was the major output pathway. Clothianidin and imidacloprid in the river and lake water would produce moderate acute ecological risks in summer. Thus, the usage of the above two NEOs should be decreased or restricted. For integral NEO risks, 53% and 58% of the river and lake water sites exceeded the acute ecological threshold, respectively. Health risk assessment suggested drinking the water obtained from the lake would not produce a negative impact on public health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Neonicotinoid (NEO) insecticides have been frequently detected in natural aquatic environments. Nevertheless, the distribution of NEOs in artificial environments is not clear. The Beijing-Hangzhou Grand Canal is the longest canal in the world. The northern Jiangsu segment of the Grand Canal was selected to study the spatiotemporal variation and source of eight NEOs in the canal water and assess their ecological and health risks. The total NEO concentration in the canal water was 12-289 ng L -1 in the dry season and 18-373 ng L -1 in the wet season, which were within the concentration range in other 11 natural rivers worldwide. The average total NEO concentrations were not statistically different between the seasons; only the concentrations of imidaclothiz, thiacloprid (THI), acetamiprid, and dinotefuran were different. At city scale, the total NEO concentration in the dry season showed a decreasing trend along the water flow from Xuzhou City to Yangzhou City. The total NEO concentrations were found to be positively correlated with the sown area of farm crops and the rural labour force, indicating the agricultural influence on the spatial distribution of NEO concentrations. In the wet season, relatively high NEO concentrations were distributed in downstream sites under the influence of artificial regulation. The primary contributor to the NEO inputs into the canal was the nonpoint source in the dry and wet seasons, with a relative contribution of 68 %. THI, imidacloprid, clothianidin and thiamethoxan would produce chronic ecological risks in both seasons. Further consideration needs to be given to the above four NEOs and NEO mixtures. The human health risks that NEOs posed by drinking water were assessed based on the chronic daily intake (CDI). The maximum CDI for adults and children was lower than the reference doses. This suggested public health would not be at risk from canal water consumption., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Fabrication of facile, sensitive, and accurate pesticide detection strategies plays crucial roles in food safety, environmental protection, and human health. Here, a novel esterase activatable aggregation-induced emission (AIE) plus excited-state intramolecular proton transfer (ESIPT) probe, kaempferol tetraacetate, was designed and synthesized from purified natural kaempferol for ratiometric sensing of carbaryl. Acetate groups are introduced as the esterase reactive sites and AIE plus ESIPT initiator. Kaempferol tetraacetate is an aggregation-caused quenching compound that shows fluorescent (FL) emission at 415 nm. Esterase specifically hydrolyzes kaempferol tetraacetate to kaempferol with AIE plus ESIPT characteristics (distinct FL emission, 530 nm; a large Stokes shift, 165 nm within a short time (8 min). Molecular docking and kinetics performance indicate the high affinity and specific hydrolysis of esterase and kaempferol tetraacetate. Carbaryl inhibits the activity of esterase to efficiently suppress the production of kaempferol. Thus, a facile ratiometric assay strategy is constructed for carbaryl detection. By measuring the FL intensity ratio, the proposed strategy presents high selectivity and reliability with a wide linear range from 0.02 to 2.00 μg L -1 and a very low limit of detection at 0.007 μg L -1 . Furthermore, appropriate recovery from 93.75% to 108.67% with a relative standard deviation less than 5.66% for real sample analysis indicates good accuracy and precision. All results indicate that the fabricated strategy offers a new way for facile, sensitive, and accurate detection of carbaryl in real complex samples., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Limited information is available on the spatiotemporal occurrence and ecological risks of organophosphate esters (OPEs) in coastal environments. 175 water samples were collected in Laizhou Bay (LZB) and its rivers and estuaries during spring and summer for the determination of 12 targeted OPEs. Total concentration of OPEs ranged from 234.4 to 2892.1 ng L -1 in the river and estuarine water and 87.6 to 969.4 ng L -1 in the bay water, with medians of 1015.8 and 296.8 ng L -1 , respectively, showing that riverine inputs were the major sources of OPEs in the bay. Tris (2-chloroisopropyl) phosphate (TCIPP) and triethyl phosphate (TEP) were the most abundant OPEs, with median contributions of 47% and 36% in the bay water, respectively. The total concentration of OPEs was higher in the estuarine area of the Yellow River and the southwestern coast of the LZB under the influence of riverine OPE inputs and ocean currents. In addition, the concentrations of dominant OPE species were significantly higher in the surface water than in the bottom water. The concentrations of dominant OPE species were found to be significantly lower in summer than in spring, mainly due to both precipitation and seawater dilution effects. However, the concentrations of three minor OPE species were significantly higher in summer than in spring, probably because of their high usage in summer. TCIPP and TEP concentrations were significantly negatively correlated with salinity. The targeted OPEs posed low ecological risk in the bay and moderate ecological risk in the rivers and estuaries, which was mostly ascribed to the toxicity of tris (2-chloroethyl) phosphate (TCEP) and resorcinol-bis (diphenyl) phosphate (RDP) to algae. Priority should be given to TCIPP, TEP, TCEP, and RDP in the LZB due to their high concentrations and/or toxicity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Coastal contamination by polycyclic aromatic hydrocarbons (PAHs) is a worldwide issue. Nevertheless, the spatiotemporal distribution of PAHs in the urbanized semi-enclosed bays in China remains relatively uncharacterized. Here we present measurements of 15 priority PAHs in the water and sediment of the Jiaozhou Bay, as well the assessment of their spatiotemporal distribution, sources and ecological risk. The total PAH (ΣPAH) concentrations ranged from 23.6 to 86.2 ng L -1 in the water and from 37.7 to 290.9 ng g -1 in the sediment. The average ΣPAH concentration in the water was significantly higher in the winter (52.8 ng L -1 ) than in the spring (30.4 ng L -1 ) (α = 0.05 level). Average concentration of phenanthrene in the water was 8.9 ng L -1 in the spring and 15.7 ng L -1 in the winter and the highest of PAHs, contributing about 29.4% to ΣPAHs. Compared with three-ring PAHs, four- and five-ring PAHs were more tended to accumulate in the sediment, and the partitioning into sediment was influenced by the water salinity. The spatial distribution of ΣPAH concentrations in the water were controlled by water exchange capability. Organic matter content and sediment texture played important roles in determining the spatial distribution of ΣPAHs in the sediment. Molecular diagnostic ratio analysis indicated that pyrogenic source was the main source for PAHs in the Bay. Specifically, the positive matrix factorization (PMF) model indicated that vehicle emission, biomass combustion, coal combustion, and petrogenic sources contributed for 41.6, 20.2, 20, and 18.2% of ΣPAHs, respectively. The risk assessment by sediment quality guidelines suggested that adverse biological effects are expected to occur rarely in the sediment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Plateau lakes are typically dystrophic and are sensitive to small changes in nutrient deposition. With this assumption, we investigated the concentrations, fluxes, and sources of nitrogen (N) and phosphorus (P) in the atmospheric wet deposition (AWD) of the Lake Qinghai Watershed (LQW), which is the largest inland lake in China, for one year from October 2017 to September 2018. The results showed that the annual volume-weighted mean (VWM) concentrations (mg L -1 ) in the AWD were 1.97 for NH 4 + -N, 0.55 for NO 3 - -N, 0.04 for NO 2 - -N, 0.77 for dissolved organic N (DON), 3.33 for total dissolved N (TDN), 0.30 for dissolved inorganic P (DIP), 0.07 for dissolved organic P (DOP), 0.36 for total dissolved P (TDP), and 0.99 for reactive sulfur (SO 4 2- -S). The annual AWD fluxes of TDN and TDP were 16.82 and 1.86 kg ha -1  yr -1 , respectively. Strong dilution effects in the wet season, a long residency time of nutrient-rich aerosols in the dry season, strong ammonia volatilization in the wet and warm seasons, and moisture sources dominated the seasonal or monthly changing characteristics of N and P concentrations in the AWD, including high in the wet season and low in the dry season for NH 4 + -N, low in the wet season and high in the dry season for NO 3 - -N, and generally increasing from April to September for DIP and DOP. Precipitation quantity dominated the monthly changes in the N and P fluxes of the AWD, which gradually increased from April to August and then decreased in September. N and P in the AWD mostly originated from anthropogenic sources. High ammonia volatilization from local intense animal husbandry, alkaline soils and lakes led to a relatively high NH 4 + -N concentration compared with other sites of the Qinghai-Tibet Plateau, China, and in the world. The N/P molar ratio in the precipitation was higher than 16, which might have effect on the aquatic ecosystems of Lake Qinghai. Ammonia volatilization fluxes and atmospheric dry deposition fluxes of N and P should be further studied to completely understand the geochemical cycles of N and P in the LQW., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Contamination of trace metals in urban rivers is a global problem. The objective of this study was to investigate the contamination and ecological risks of trace metals in the Hai River, which receives substantial effluents from the Beijing-Tianjin region. A total of 43 surface water and sediment samples were collected and analyzed for physiochemical properties and toxic elements. The concentrations of Cd, Cr, Ni, Pb, Cu and Zn in the river water met the Chinese environmental quality grade I standards for surface water. The average total concentrations of Zn, Cr, V, Cu, Pb, Ni, Co, Sc and Cd in the sediments were 144.2, 77.5, 70.1, 46.1, 40.1, 29.6, 12.4, 9.9 and 0.26 mg/kg, respectively. The enrichment of Cd, Cr, Cu, Pb and Zn in the sediments was influenced by anthropogenic activity, as indicated by the enrichment factor (EF) and multivariate analysis. The concentrations of Co and Cr in the sediments were predominantly in residual fractions, while relatively higher amounts of Cd, Pb, Zn and Cu were in non-residual fractions. There was a significant correlation between concentrations of Cd, Co, Cr, Cu, Pb and Zn in non-residual fractions and their corresponding EF values (P < 0.01). This result further demonstrated that anthropogenic inputs were an important contributor to metal enrichment. The high bioavailability of Cd and poor bioavailability of Co and Cr in the sediments were demonstrated by the single extraction procedure. The significant correlation between concentrations of Cd, Cu, Pb and Zn in non-residual fractions and their concentrations in EDTA-extractable fractions was established (P < 0.01). This result indicates that single-step EDTA extraction may represent a useful procedure for assessing the bioavailability of Cd, Cu, Pb and Zn in riverine sediments. The ecological risks of the metals studied in the Hai River sediments were at a low level, dominated by the risks imposed by Cd., (Copyright © 2018 Elsevier Inc. All rights reserved.)