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Are the residues of organochlorine pesticides (OCPs) in freshwater in China still of concern after prohibition and restriction for decades? The scarcity of monitoring data on OCPs in freshwater in China over the past few years has hampered understanding of this issue. In this study, water and suspended particulate matter (SPM) samples were collected from the middle reach of the Huai River for OCP analyses. Residues of ∑OCPs in water and SPM ranged from ND to 8.6 ng L−1 and 0.50 to 179 ng L−1, with mean concentrations of 1.7 ± 1.3 ng L−1 and 6.1 ± 31 ng L−1, respectively. ∑HCHs (α-, β-, γ-, and δ-HCH) and ∑HEPTs (heptachlor and heptachlor epoxide) were the most predominant pesticides in the dissolved phase and SPM, respectively, accounting for 43 ± 35% and 27 ± 29% of ∑OCPs. HCHs and heptachlor epoxide mainly existed in the dissolved phase, while heptachlor mainly existed in SPM. The isomeric composition pattern of HCHs in water differed from that in SPM. Briefly, β-HCH dominated in water, while δ-HCH dominated in SPM. However, the composition pattern of DDT and its metabolites in water was similar to that in SPM. o,p'-DDD and p,p'-DDE dominated in both water and SPM. The ratios of α-/γ-HCH and (DDD + DDE)/DDTs indicated that HCHs and DDTs were mainly derived from historical residues. Risk assessments indicated that OCPs may not pose carcinogenic and non-carcinogenic risks to residents. [ABSTRACT FROM AUTHOR]

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This is the first comprehensive report on antibiotics in the Huai River, a major Chinese river. To illuminate the concentrations, prioritization, spatial distributions, sources, and ecological risks of antibiotics, surface water samples were collected and three types of most widely used antibiotics (16 sulfonamides, 8 tetracyclines, and 14 quinolones) were analyzed. The results indicated that concentrations of ∑quinolones (86 ± 31 ng/L) > ∑tetracyclines (20 ± 13 ng/L) > ∑sulfonamides (11 ± 3.7 ng/L). Oxolinic acid (OXA), cinoxacin(CINX), norfloxacin (NFX), and methacycline (MTC) were the priority antibiotics with mean concentrations > or close to 10 ng/L, however, they were rarely included as target compounds in most previous Chinese investigations. Different spatial distributions of antibiotics were discovered across three reaches separated by two sluices, demonstrating that the sluices may impact antibiotic dissemination. According to the results of the source analysis, the aquaculture industry was the major source of observed antibiotics (49%), followed by livestock & poultry farming (26%) and mixed sources (25%). Because commercial fishing in the Huai River has been prohibited, the aquaculture industry will expand in the next years, and antibiotic contamination caused by the aquaculture industry deserves more attention. The risk quotients were calculated by comparing observed antibiotics to predicted no-effect concentrations, and the results showed that observed antibiotics posed negligible or low integrated risks for Green algae, and medium or low integrated risks for Daphnia magna. [ABSTRACT FROM AUTHOR]

We examine the effect of air pollution on innovation activity by studying city-level patenting activities and air pollution index (API) in China. We use a novel quasi-natural experiment of China's Huai River policy, which provides subsidy for winter heating to cities north of the Huai River but not to cities to the south, to estimate the impact of air pollution on innovation performance. Based on spatial regression discontinuity design, we find that API is 0.145 higher in the north and the number of patents per city is 25.5% lower in the north. Further analysis shows that increases in API are associated with significant reduction in the number of patents per city, suggesting that air pollution significantly impedes innovation activities. [ABSTRACT FROM AUTHOR]

Precipitation plays a critical role in hydrometeorological studies. A predictive analysis of gridded rainfall datasets may provide a cost-effective alternative to conventional rain gauge observations. Here, our objective is to evaluate the performance of satellite and reanalysis precipitation products in the hydrological modeling of a mesoscale watershed. The research also examines the accuracy of hydrological simulations in a sizeable flood-prone watershed in the absence of observed data associated with the myriad water retaining structures present in the catchment. We use three precipitation products, namely Tropical Rainfall Measurement Missions (TRMM) 3B42 Version 7, Climate Forecast System Reanalysis (CFSR), and daily precipitation data recorded at multiple rain gauges in the upper Huai River Basin to simulate streamflow. The Soil & Water Assessment Tool (SWAT) is utilized for runoff modeling, while SWAT-CUP is used to perform sensitivity analysis and to calibrate and validate the simulation results. Nash–Sutcliffe efficiency, percent bias, and Kling-Gupta efficiency (KGE) are employed to evaluate modeling efficiency for three precipitation datasets on different temporal scales. The results indicate that TRMM and CFSR datasets provide satisfactory results on both daily and monthly scales. Specifically, the SWAT model performs better at monthly simulations than daily simulations for all precipitation datasets used. HIGHLIGHTS Examining the applicability of TRMM and CFSR daily precipitation products in simulating runoff from a large watershed.; Calibrating a hydrological model in the absence of data associated with extensive anthropogenic activities for flood prevention and diversion.; Performing streamflow simulations using a SWAT model and parameter calibration and sensitivity analysis using a SUFI-2 algorithm.;

The complete mitogenome sequence of Coilia brachygnathus (Kreyenberg & Pappenheim, 1908) from Wabu Lake in Huai River Basin was annotated and characterized in this study. This mitochondrial genome is a circular DNA molecule of 16.896 bp in size with 57.52% AT content, including 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and an AT-rich region (control region) as other bony fishes. There are a total of 10 overlap locations and 15 intergenic spacer regions throughout the mitogenome of C. brachygnathus. All PCGs employed a standard ATG as a start codon, except cytochrome c oxidase 1 (cox1) with GTG. In addition, TAA or TAG was identified as the typical stop codon. A phylogenetic tree reconstructed with the maximum likelihood method depicted a clone relationship with eight species of genus Coilia and our previous study based on the amino acid sequences of 13 mitochondrial PCGs. The complete mitochondrial genome is a valuable resource in classifying and conserving C. brachygnathus.

The use of rice and millet has been uncovered at a few archaeological sites associated with the Shuangdun Culture (ca. 7.3–6.8 ka BP) in the middle catchment of the Huai River, China. Nevertheless, the consumption of rice, millet, and other types of plant foods at other contemporaneous sites in the same region still needs supporting information from more case studies. This article examines pottery sherds (n = 21) excavated from another representative Shuangdun Culture site at Houjiazhai with starch grain analysis. Varied types of pottery vessels contain starch remains from rice (Oryza sativa), foxtail millet (Setaria italica), broomcorn millet (Panicum miliaceum), Job’s tears (Coix lacryma-jobi), Triticeae, roots of snake gourd (Trichosanthes kirilowii), lotus root (Nelumbo nucifera), Chinese yam (Dioscorea panthainca), lily bulbs (Lilium sp.), acorns (Quercus sp.), and beans (Vigna sp. or/and Vicia sp.). Further quantitative analysis of the starch data indicates that cereals, including rice and millet, were predominantly consumed in the pottery vessels. Changes and continuities of culinary practices are also present at Houjiazhai, which are reflected in the different pottery assemblages as well as the utilized plant species in different occupation phases at the site. Combining previous studies, this article also reveals the differences and similarities of the past population in choosing their plant food resources during the period of Shuangdun Culture in the middle catchment of the Huai River, China.

Precipitation plays a critical role in hydrometeorological studies. A predictive analysis of gridded rainfall datasets may provide a cost-effective alternative to conventional rain gauge observations. Here, our objective is to evaluate the performance of satellite and reanalysis precipitation products in the hydrological modeling of a mesoscale watershed. The research also examines the accuracy of hydrological simulations in a sizeable flood-prone watershed in the absence of observed data associated with the myriad water retaining structures present in the catchment. We use three precipitation products, namely Tropical Rainfall Measurement Missions (TRMM) 3B42 Version 7, Climate Forecast System Reanalysis (CFSR), and daily precipitation data recorded at multiple rain gauges in the upper Huai River Basin to simulate streamflow. The Soil & Water Assessment Tool (SWAT) is utilized for runoff modeling, while SWAT-CUP is used to perform sensitivity analysis and to calibrate and validate the simulation results. Nash-Sutcliffe efficiency, percent bias, and Kling-Gupta efficiency (KGE) are employed to evaluate modeling efficiency for three precipitation datasets on different temporal scales. The results indicate that TRMM and CFSR datasets provide satisfactory results on both daily and monthly scales. Specifically, the SWAT model performs better at monthly simulations than daily simulations for all precipitation datasets used. [ABSTRACT FROM AUTHOR]

Village-level agricultural specialization in China is becoming increasingly important for rural development. However, existing knowledge of specialized agricultural villages (SAVs) based on singular assessment criteria and data describing static time points becomes insufficient in addressing multifaceted developmental questions today. We examined the long-term development patterns of SAVs in Anhui, China, with attributes from multiple angles, and explored how local factors affected SAV development across space and time using random forest regression. We found that as time elapsed, economic rationality drove specialized farmers closer to sale dependency and made SAVs more susceptible to market and economic factors, which builds upon previous findings analyzing SAVs at specific time points and consolidates the importance of market factors in the long-term development of SAVs. However, this susceptibility manifests differently in these two geographically contrasting regions north and south of Huai River. The northern SAVs received increased influences from market and economic factors, while the southern SAVs were continuously controlled by market and location factors. The dynamic spatial and temporal patterns of the two regions point to different dependencies, which emphasized local sales in the north and distant sales in the south. We propose that policies and strategies regarding SAV development accommodate these dynamics and address appropriate influencing factors accordingly. [ABSTRACT FROM AUTHOR]

The development and adoption of agriculture has been investigated for decades, and remains a central topic within archaeology. However, most previous studies focus on the crop’s domestication centers, leading to gaps in knowledge, particularly in transitional zones between these centers. This paper reviews published archaeobotanical evidence and historical documents to reconstruct the trajectory of agricultural systems in Holocene Jiangsu Province. Comparing these new results to paleoclimate information, historical documents, and archaeological data enables us to better understand the underlying influences of past agricultural development. Our results indicate that a warm and wet climate may have promoted ancient peoples to first settle in Jiangsu between 8,500 and 6,000 BP and adopt rice farming. The continuous warm and wet climate may have facilitated the rapid development and expansion of rice agriculture, ultimately contributing to large-scale human settlement in 6,000–4,000 BP in Jiangsu Province. Between 4,000 and 2,300 BP during a cooler and drier climate millet agriculture diffused southward, facilitating a mixed rice and millet agricultural system. This mixed farming supported a continuesd widespread settlement and population growth in Jiangsu. After 2,300 BP, political instability in north China resulted in further southeastward migration, advanced planting technology was brought about to south China, facilitating highly developed agricultural systems and rapid population expansion in Jiangsu. Population growth led to the establishment of Jiangnan as the regional economic center, where people chose high-yielding rice and wheat rather than millet.

The complete mitogenome sequence of Coilia brachygnathus (Kreyenberg & Pappenheim, 1908) from Wabu Lake in Huai River Basin was annotated and characterized in this study. This mitochondrial genome is a circular DNA molecule of 16.896 bp in size with 57.52% AT content, including 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and an AT-rich region (control region) as other bony fishes. There are a total of 10 overlap locations and 15 intergenic spacer regions throughout the mitogenome of C. brachygnathus. All PCGs employed a standard ATG as a start codon, except cytochrome c oxidase 1 (cox1) with GTG. In addition, TAA or TAG was identified as the typical stop codon. A phylogenetic tree reconstructed with the maximum likelihood method depicted a clone relationship with eight species of genus Coilia and our previous study based on the amino acid sequences of 13 mitochondrial PCGs. The complete mitochondrial genome is a valuable resource in classifying and conserving C. brachygnathus. [ABSTRACT FROM AUTHOR]

To achieve precision control of water resources in the Huai River Basin, the precision of the forecast and control of such resources must be improved. In the present study, a recharge method was applied to the basic data obtained from the quantitative forecast and precision control of water resources in the Huai River. In addition, the water balance method was used to analyze the spatiotemporal characteristics of the water resources in the Huai River ecological-economic belt (hereafter the eco-economic belt). Using data on water resources in the eco-economic belt from 1998 to 2018, we explored the spatiotemporal changes and the characteristics of the water resources in the region. The analysis revealed the following: (1) The eco-economic belt has abundant water resources with regard to total volume, but they are unevenly spatiotemporally distributed. (2) The water resources in the eco-economic belt display a declining trend. Abundant water resources are concentrated in the provinces of Anhui, Henan, and Jiangsu, while they are relatively scarce in Hubei. (3) Examination of the changes in the water resources of the provinces located in the eco-economic belt indicates substantial changes in total water resources and rainfall on an annual basis. Henan and Anhui had the largest and smallest annual changes in total water resources, respectively. The rainfall changes are essentially periodic; that is, they alternate annually between high and low over time. Henan and Hubei had the highest changes in surface water resources and groundwater resources, respectively. (4) Rainfall is the primary source of the water resources in the eco-economic belt. The spatial distributions of surface water and groundwater are consistent. Overall, the present study provides valuable empirical evidence of water resource control in the eco-economic belt. [ABSTRACT FROM AUTHOR]

Floods out of all other water problems cause very large damages in China. Previous flood management plans mainly focused on a single river by controlling its water level and conveyance capacity, while research on mitigation solutions to flooding issues in river-lake systems is scarce. This study considers the Huai River - Lake Hongze system, which is one of the largest river-lake systems in China. Very large damages associated with small floods are frequently observed in this river-lake system, although a series of flood management measures have been implemented in the Huai River Basin since the middle of the last century. An unstructured-grid finite-volume numerical model was applied to simulate hydrodynamic processes in this system, which is characterized by discrepant spatial scales between these two types of water bodies. It is found that the lake affects the upstream river flooding, but lowering the lake level would have limited effects that would be rapidly impaired by the sharp meander bend connecting the river and the lake. The artificial cutoff of this intensively-embanked bend has great potential in reducing the river stage and flood damages, as the construction of a diversion channel would shorten the flow path and increase the hydraulic gradient. This study extends the current knowledge about the hydrodynamics of river-lake systems and is beneficial to flood mitigation strategies for similar systems. [ABSTRACT FROM AUTHOR]

The occurrence and spatial distribution of priority pharmaceuticals (PPs) in water samples from the Yellow River and the Huai River in the Henan region of China were investigated in this study. The concentration of the total PPs (ΣPPs; sum of the 10 observed PPs) ranged from not detected to 3474 ng L−1 in samples from the Yellow River and from 4.35 to 146 ng L−1 in samples from the Huai River. The level of the ΣPPs in the Huai River was much lower than that found in the Yellow River. The composition of the PPs differed between the two rivers. Norfloxacin, carbamazepine, and 5,5-diphenylhydantoin were detected at high concentrations in the Yellow River, whereas sulfamethazine, ampicillin trihydrate, carbamazepine, and 5,5-diphenylhydantoin were the dominant species in the Huai River, suggesting there were different pollution sources. In comparison to other studies around China, most of the PPs in water samples from the Yellow River and the Huai River were at low concentrations, except for norfloxacin and ofloxacin. There were significant seasonal variations among the PPs in water samples from the Huai River, whereas spatial distinctions were recorded among the PPs in the Yellow River. Dissolved organic carbon content did not correlate with the PPs in the studied area. [ABSTRACT FROM AUTHOR]

In recent years, the incoming sediments from upstream of the Huai River have continuously decreased. The relationship between flow and sediment has significantly changed. Therefore, the erosion and deposition characteristics of the river could be affected. To investigate this interaction between flow and sediment, the present study was conducted using the Wanglin section in the middle reach of the Huai River as the study site. A 1D hydrodynamic model was developed and validated using field data. Data from 1985–2014 were used as a continuous series while data from 2004–2014 were used as a repetitive series. The sediment variation and distribution processes at different locations were discussed. It was found that the river channel displayed several notable characteristics. In the flow direction, the channel had frontal erosion and backward deposition. The variation rate was relatively slow. With reduced sediment, the overall deposition at the Wanglin section was significantly mitigated. Future recommendations are provided based on the present simulation for flood mitigation along the Huai River.

Solid phase extraction has been increasingly applied for the detection of organic micropollutants (OMPs). However, time-consuming and high-cost disadvantages also limit the widespread use of this method, especially for the extraction of large-volume field water samples. In this study, a gas chromatography-mass spectrometry (GC-MS) method based on the magnetic microsphere (M150) solid-phase-extraction (MSPE) was established to investigate the OMPs in source water throughout the whole Huai River. In brief, the results demonstrated that the extraction efficiency of the M150 was superior to that of C 18 and HLB for the selected OMPs, including species of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), phthalate esters (PAEs) and nitrobenzenes (NBs), and the method detection limits of M150 for these OMPs were comparable to those of C 18 and HLB. The optimized conditions of extraction and elution were the 100 mg/L dosages of microspheres, extraction time of 60 min and pH of 2, and the eluent with a similar polarity, hydrophobicity and molecular structure to the OMPs rendered higher elution efficiencies. A total of 21 types of OMPs affiliating to PAHs, OCPs, PAEs and NBs were detected by the established method, with the total concentrations of 505–2310 ng/L in source water of the Huai River. Spatial differences of the OMPs were also observed, demonstrating the link between pollutant profiles and geographical locations. This study provides an alternative to enrich OMPs in filed water samples, and it reveals pollutant profiles of source water throughout the whole Huai River. Image 1 • Extraction and elution procedures for detection of selected OMPs were optimized. • Enrichment performances of M150, C 18 and HLB were compared. • Spatial differences of the OMPs were observed in source water of the Huai River. A highly sensitive and efficient magnetic microsphere solid-phase-extraction method was established and applied to investigate the selected organic micropollutants in the source water of the Huai River. [ABSTRACT FROM AUTHOR]

The thick ' Xiashu loess' in southern China is distributed not only in the Yangtze River valley, but also and most extensively in the region between the Qinling Mountains and the lower reaches of the Yangtze River. However, there are few studies of the provenance and climatic implications of the Xiashu loess in this latter region. Here we present the results of a provenance study of Last Glacial loess samples from twenty-two typical Xiashu loess sections, using the major and trace element composition as a provenance indicator. Seventeen of the sites are located to the north of the Yangtze River and our primary aim was to determine the provenance of the Xiashu loess within this region. Our results indicate that the alluvial plain located mainly in the present drainage area of the Huai River was the primary dust source for the Xiashu loess in this region. The occurrence of multiple local dust sources within this alluvial plain, suggested by their geochemical heterogeneity, indicates that the alluvial plain experienced intensified aridity which caused it to become a dust source for local loess deposits in northern subtropical China during the Last Glacial. Our study provides strong evidence to challenge the long-held view that the occurrence of Xiashu loess resulted from the southward incursion of the CLP loess deposits sourced from deserts of the Asian interior, and it confirms the substantial role of aridification of the present humid northern subtropical region for dust emission to the climate system during the Last Glacial. • Major and trace element composition of samples from 22 Xiashu loess sections. • The Xiashu loess was not primarily derived from the Asian interior deserts. • Geochemical heterogeneity indicates local dust sources in the alluvial plain. • Alluvial plain in northern subtropical China aridified during the Last Glacial. [ABSTRACT FROM AUTHOR]

Abstract In this study, six alkyl esters of p-hydroxybenzoic acids (parabens) and their metabolite, 4-hydroxybenzoic acid (p-HB) were simultaneously determined in surface water and sediment from the Yellow River and the Huai River in Henan Province, China. Concentrations of ∑parabens in surface water were 3.31–55.2 ng/L in the Yellow River and 15.0–164 ng/L in the Huai River, while in the sediment, concentrations of ∑parabens were 13.3–37.2 ng/g and 16.1–31.6 ng/g, respectively. Compared with other studies, levels of parabens in the studied area were relatively high in the sediments but middle in the surface water. MeP and PrP were the most abundant parabens, and were detected in all sampling sites. Contributions of EtP, BzP, BuP, and HeP to ∑parabens were each no more than 10%. 4-Hydroxybenzoic acid was found in all samples albeit at low concentrations. Significant positive correlations among parabens suggest similar sources of parabens in the Yellow River and the HuaiRiver. Dissolved organic carbon (DOC) had an important effect on parabens in the surface water of the Yellow and Huai Rivers. Due to low dilution of discharges, high concentrations of parabens were found during moderate precipitation season as well as minimal precipitation season in surface water. However, no apparent seasonal variation of parabens in surface sediment was observed. Hazard quotients showed that the ecological risks of parabens was low in the studied area. Graphical abstract fx1 Highlights • Parabens and p-HB in the Yellow River and the Huai River were evaluated. • MeP and PrP were the most abundant parabens in surface water and surface sediment. • Apparent seasonal variation of Parabens in surface water was detected. • The ecological risk assessment of parabens in the studied area was low. [ABSTRACT FROM AUTHOR]

Due to serious nitrogen pollution in the Huai River, Eastern China, nitrogenous concentrations and dual stable isotopes (δ15N and δ18O) were measured to ascertain the sources and transformation of nitrogen in the Shaying River, the largest and most polluted tributary of the Huai River during the summer and winter seasons. Total nitrogen (TN), NO3−, and NH4+ were significantly higher in winter, with values of 7.84 ± 3.44 mg L−1, 2.31 ± 0.81 mg L−1, and 3.00 ± 2.24 mg L−1, respectively, while the highest nitrogen compounds occurred in the Jialu River, one of the tributaries of the Shaying River, in both summer and winter. Isotope characteristics of nitrate reveal that manure and sewage were the principal nitrate sources in both summer (62.44 ± 19.66%) and winter (67.33 ± 15.45%), followed by soil organic nitrogen, with 24.94 ± 15.52% in summer and 26.33 ± 9.45% in winter. Values of δ15N-suspended particulate nitrogen (SPN) ranged from 0.78 to 13.51%, revealing that point source from industrial and domestic sewage accounted for the largest input to SPN at most sites, whereas soil organic nitrogen and agricultural fertilizers were found in the Jialu River in both sampling periods. Point sources from septic/manure and household waste were the main contributors to ammonium in most river water samples in both summer and winter; most wastewater discharged into the river was untreated, which was one of the main reasons for the high level of ammonium in winter. Nitrogen pollution and the dams had an effect on N transformation in the river. Significant assimilation of NH4+ and aerobic denitrification competed for NH4+, resulting in the weakness of nitrification in the summer. Denitrification was also an important process of nitrate removal during the summer, whereas nitrification was a key N transformation process in the river in the winter time. To reduce nitrogen pollution and improve water quality, greater effort should be focused on the management of sources from urban input as well as on the improvement in sewage treatment. [ABSTRACT FROM AUTHOR]

Abstract The historical trends and spatial distributions of 15 polycyclic aromatic hydrocarbons (PAHs) in sediments from the upper reach of the Huai River were investigated. The concentrations of total PAHs (ΣPAHs) in the surface sediments varied from 3.96 to 379 ng/g (average: 65.3 ng/g). PAHs in the surface sediments of the studied area were at a low level compared with some other rivers around the world. The component characteristics showed that four-ring PAHs were predominant. The principal component analysis-multiple linear regression (PCA/MLR) showed that PAHs in the surface sediments primarily originated from coal combustion and vehicular emissions, which accounted for 62.7% and 37.3% of ΣPAHs, respectively. The concentration of ΣPAHs in the sediment core ranged from 2.31 to 21.9 ng/g with deposition flux ranging from 1.91 to 33.3 ng/cm2/year. The historical pattern of PAHs correlated with the Chinese socioeconomic conditions during 1912–2014, confirming that PAHs are a sensitive tracer for anthropogenic activity. Since the 1980s, there was a sharp increase in PAHs concentrations in the studied core. PCA/MLR showed that PAHs in the sediment core were mainly from the burning of fossil fuels. The concentration of PAHs in the surface sediment and sediment core was affected by the content of total organic carbon and black carbon. The result revealed in this study could serve as a reference for the development of relevant remedial strategies for the management of the Huai River. Highlights • Sediment core from the upper reach of the Huia River were analyzed for PAHs. • One century deposition of PAHs was reconstructed. • The depositional flux of PAH generally showed an increasing trend. • Temporal profiles of PAHs reflected local economic conditions. [ABSTRACT FROM AUTHOR]

Neonicotinoids (NEOs) are the most widely used insecticides in the world. Nevertheless, the occurrence and distribution of NEOs in agricultural areas are not well understood. This study investigated the concentration, sources, ecological risks, and health risks of eight NEOs in the water of the Huai River, which flows through a typical agricultural area in China. The total concentration of NEOs in the river water ranged from 1.02 to 191.2 ng L−1, with an average of 64.1 ng L−1. Thiamethoxam was the dominant compound, with an average relative contribution of 42.5%. The average concentration of the total NEOs in downstream was significantly higher than that in upstream (p < 0.05). This may be related to the intensity of agricultural activities. The riverine NEO fluxes increased by approximately 12 times from the upper site to the lower site. More than 1.3 tons of NEOs in 2022 were transferred into Lake Hongze, the largest regulative lake on the Eastern Route of the South-to-North Water Diversion Project. Nonpoint sources were the major contributor to the total NEO inputs, and water use was the main output pathway. The risk assessment indicated that the individual NEOs in the river water presented low ecological risks. The NEO mixtures would produce chronic risks to aquatic invertebrates in 50% of the sampling sites, which were mostly distributed in downstream. Thus, more attention should be given to the downstream. Based on the Monte Carlo simulation, the health risks of NEOs via water consumption were estimated. The maximum chronic daily intakes were 8.4 × 10−4, 2.25 × 10−4, 1.27 × 10−4, 1.88 × 10−4 mg kg−1 day−1 for boys, girls, men, and women, respectively, which were approximately 2 orders of magnitude lower than the acceptable daily intake. Therefore, river water consumption would not be a concern for the public health. [Display omitted] • Neonicotinoid (NEO) concentrations related to agricultural activity intensity. • Riverine NEO fluxes increased by 12 times from upper sites to lower sites. • The nonpoint source was the major contributor to the total NEO input. • NEOs pose chronic risks to aquatic invertebrates mostly in downstream. • Health risks via water consumption for children were higher than for adults. [ABSTRACT FROM AUTHOR]

The extensive constructions of reservoirs change the hydrologic characteristics of the associated watersheds, which increases the complexity of watershed flood control decisions. By evaluating the impacts of the multi-reservoir system on the flood hydrograph, it becomes possible to improve the effectiveness of the flood control decisions. This study compares the non-reservoir flood hydrograph with the actual observed flood hydrograph using the Lutaizi upstream of Huai River in East China as a representative case, where 20 large-scale/large-sized reservoirs have been built. Based on the total impact of the multi-reservoir system, a novel strategy is presented to evaluate the contribution of each reservoir to the total impact. According their contributions, the 'highly effective' reservoirs for watershed flood control are identified via hierarchical clustering. Moreover, the degree of impact of the reservoir operation rules on the flood hydrograph are estimated. We find the multi-reservoir system of Huai River has a significant impact on flooding at the Lutaizi section, on average reducing the flood volume and peak discharge by 13.92 × 10 m and 18.7% respectively. Under the current operation rules, the volume and peak discharge of flooding at the Lutaizi section are reduced by 13.69 × 10 m and 1429 m/s respectively. Each reservoir has a different impact on the flood hydrograph at the Lutaizi section. In particular, the Meishan, Xianghongdian, Suyahu, Nanwan, Nianyushan and Foziling reservoirs exert a strong influence on the flood hydrograph, and are therefore important for flood control on the Huai River. [ABSTRACT FROM AUTHOR]

Saliva and Urine samples were collected for the study on how nitrate and nitrite concentration in human body may be related to the corresponding health risk in a high cancer incidence area. The study area includes three known cancer villages in Huai River basin, China. The results of analyzing collected sample show that there are higher levels of nitrate and nitrite concentration in human saliva and urine sample collected in the study area as compared to those collected in other areas. In addition, levels of nitrate and nitrite concentration in saliva and urine sample change significantly with the ages of sampled population. NO3-concentrations in saliva and urine sample are the most outstanding among the middle-aged and elderly populations. It means that the middle-aged and elderly populations have relatively high vivo nitrate reductive transformation rates and they also have higher N-nitroso compounds synthesis risks in the studied cancer villages. [ABSTRACT FROM AUTHOR]

Reclaimed water is efficient for replenishing the dry rivers in northern China, but regional groundwater may be at risk from pollution. Therefore, samples of reclaimed water, river water, and groundwater were collected at the Huai River in the Chaobai River basin in 2010. The water chemistry and isotopic compositions of the samples were analyzed in the laboratory. The reclaimed water had stable compositions of water chemistry and isotopes, and the Na·Ca-HCO·Cl water type. The water chemistry of the river water was consistent with that of the reclaimed water. A June peak of total nitrogen was the prominent characteristic in the shallow groundwater, which also had the Na·Ca-HCO·Cl water type. However, the water chemistry and isotopes in most of the deep groundwater remained stable, and the water type was Ca·Mg-HCO. The amount of reclaimed water recharging the groundwater was about 2.5 × 10 m/yr. All of the shallow groundwater was impacted by the reclaimed water, with the mixing proportion of reclaimed water ranging from 42% to 80 % in the dry season and from 20% to 86% in the wet season. Only one deep well, with proportions of 67% (dry season) and 28% (wet season), was impacted. TDS, EC, and major ions (Na, K, Cl, NH-N, NO-N, and NO-N) were increased in the impacted wells. [ABSTRACT FROM AUTHOR]

This paper finds that a 10-μg/m3 increase in airborne particulate matter [particulate matter smaller than 10 μm (PM10)] reduces life expectancy by 0.64 years (95% confidence interval = 0.21-1.07). This estimate is derived from quasiexperimental variation in PM10 generated by China's Huai River Policy, which provides free or heavily subsidized coal for indoor heating during the winter to cities north of the Huai River but not to those to the south. The findings are derived from a regression discontinuity design based on distance from the Huai River, and they are robust to using parametric and nonparametric estimation methods, different kernel types and bandwidth sizes, and adjustment for a rich set of demographic and behavioral covariates. Furthermore, the shorter lifespans are almost entirely caused by elevated rates of cardiorespiratory mortality, suggesting that PM10 is the causal factor. The estimates imply that bringing all of China into compliance with its Class I standards for PM10 would save 3.7 billion life-years. [ABSTRACT FROM AUTHOR]

Changes in global climate drivers have multiple impacts on lake ecosystems, as rain and wind conditions control catchment surface runoff and lake mixing regimes. However, human activities in lakes and their watersheds may have direct and indirect impacts on aquatic optical properties. Therefore, identifying key drivers that can be controlled (human) from those that cannot (climate) represents an important objective. In the present study, we develop an algorithm to estimate the concentrations of suspended particulate matter (SPM) in Lake Hongze (the fourth largest freshwater lake in China) using MODIS/Aqua images with concurrent data collected from six cruise surveys. The algorithm resulted in root mean square errors (RMSEs) of 7.64–7.86 mg/L for SPM ranging from 10 to 80 mg/L. The algorithm was applied to 1602 cloud-free MODIS/Aqua images from 2002 to 2015. Our results show: (1) inter-annual and seasonal variations of SPM concentrations in Lake Hongze are divided into two distinct periods between 2002 and 2011 and 2012–2015, with the transition associated to intensive dredging activities that were initiated in 2012. (2) SPM concentrations exhibit four typical patterns of spatial distribution which depend on local meteorological (wind speed and wind direction) and hydrological conditions (catchment rainfall and Huai River flowrate). Based on these results, a new spatial zoning of the lake is derived to support government and agency monitoring. The study shows additive and synergistic effects of climate change and human activities on SPM concentrations over short and long timescales and the possibility to monitor these changes by remote sensing in shallow optically complex lakes. [ABSTRACT FROM AUTHOR]

The Huai fluvial system is known for its heavy metal pollution resulting from industrial activities. Here, we report V in surface sediments and sediment core from Huai River near the Huainan coal district. Sedimentation rate of 0.83 cm yr − 1 is indicated by 210 Pb dating. The sediment core has recorded the V deposition spanned 60 years (1955–2014 CE). The downstream surface sediment has the highest V concentration of 100 mg kg − 1 in the study area. A sequential extraction procedure was applied to determine the fractionation characteristics of V in sediments. Vanadium primarily exists in the residual fraction, and the lowest proportion was observed in the weak acid soluble fraction. The results of enrichment factor and geo-accumulation index ( I geo ) revealed that V in some Huai River sediments is considered as minor or moderately contaminated. The total concentration of V kept increasing since 1955 and reached a maximum value in around 2000, after which there was a decline with fluctuation until 2014. [ABSTRACT FROM AUTHOR]

A combination of the rainfall-runoff module of the Xin'anjiang model, the Muskingum routing method, the water stage simulating hydrologic method, the diffusion wave nonlinear water stage method, and the real-time error correction method is applied to the real-time flood forecasting and regulation of the Huai River with flood diversion and retarding areas. The Xin'anjiang model is used to forecast the flood discharge hydrograph of the upstream and tributary. The flood routing of the main channel and flood diversion areas is based on the Muskingum method. The water stage of the downstream boundary condition is calculated with the water stage simulating hydrologic method and the water stages of each cross section are calculated from downstream to upstream with the diffusion wave nonlinear water stage method. The input flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge. The flood flow inside the flood retarding area is calculated as a reservoir with the water balance method. The faded-memory forgetting factor least square of error series is used as the real-time error correction method for forecasting discharge and water stage. As an example, the combined models were applied to flood forecasting and regulation of the upper reaches of the Huai River above Lutaizi during the 2007 flood season. The forecast achieves a high accuracy and the results show that the combined models provide a scientific way of flood forecasting and regulation for a complex watershed with flood diversion and retarding areas.

As heated debates about the origin of rice domestication and cultivation in southern and eastern China continuously attract attention of the broad scientific community, new evidence for early rice exploitation from the regions located outside the core area of domestication, the lower Yangtze, are very important. Here, we present new archaeobotanical results of plant macrofossil and phytolith analyses, including directly dated rice grains from the sites of Dongpan (4030–3820 cal. BC) and Beiqian (3700–2900 cal. BC). These results fill (at least partly) an existing gap between the c. 8000-year-old rice remains from the Early Neolithic Houli Culture (c. 6500–5500 BC) sites north of the Shandong Highlands and the Longshan Culture (c. 2600–1900 BC) sites, where intensive rice agriculture was practiced. Neither rice nor millet made substantial contribution to the plant macrofossil assemblage at Dongpan, while broomcorn (and to a lesser extent foxtail) millet contributed up to 75% to the macrofossil assemblage at Beiqian. This increase can be interpreted as a major change in regional subsistence from strongly relying on wild resources and small scale cultivation during the Beixin Cultural period to a millet-based economy during the Dawenkou Culture. [ABSTRACT FROM AUTHOR]

Environmental problems such as eutrophication caused by excessive nutrient discharge are global challenges. There are complex pollution sources of nitrogen (N) discharge in many river basins worldwide. Knowledge of its pollution sources and their respective load contributions is essential to developing effective N pollution control strategies. N loads from all known anthropogenic pollution sources in the Upper Huai River basin of China were simulated with the process-based SWAT (Soil and Water Assessment Tool) model. The performances of SWAT driven by daily and hourly rainfall inputs were assessed and it was found that the one driven by hourly rainfall outperformed the one driven by daily rainfall in simulating both total nitrogen (TN) and ammonia nitrogen (NH 4 -N) loads. The hourly SWAT model was hence used to examine the spatiotemporal patterns of TN and NH 4 -N loads and their source attributions. TN load exhibited significant seasonal variations with the largest in summer and the smallest in spring. Despite its declining proportion of contribution downstream, crop production remained the largest contributor of TN load followed by septic tanks, concentrated animal feedlot operations (CAFOs), municipal sewage treatment plants, industries, and scattered animal feedlot operations (SAFOs). There was much less seasonal variation in NH 4 -N load. CAFOs remained the largest source of NH 4 -N load throughout the basin, while contributions from industries and municipal sewage treatment plants were more evident downstream. Our study results suggest the need to shift the focus of N load reduction from “end-of-pipe” sewage treatment to an integrated approach emphasizing stakeholder involvement and source prevention. [ABSTRACT FROM AUTHOR]

Despite the significant role of precipitation in the hydrological cycle, few studies have been conducted to evaluate the impacts of the temporal resolution of rainfall inputs on the performance of SWAT (soil and water assessment tool) models in large-sized river basins. In this study, both daily and hourly rainfall observations at 28 rainfall stations were used as inputs to SWAT for daily streamflow simulation in the Upper Huai River Basin. Study results have demonstrated that the SWAT model with hourly rainfall inputs performed better than the model with daily rainfall inputs in daily streamflow simulation, primarily due to its better capability of simulating peak flows during the flood season. The sub-daily SWAT model estimated that 58 % of streamflow was contributed by baseflow compared to 34 % estimated by the daily model. Using the future daily and 3-h precipitation projections under the RCP (Representative Concentration Pathways) 4.5 scenario as inputs, the sub-daily SWAT model predicted a larger amount of monthly maximum daily flow during the wet years than the daily model. The differences between the daily and sub-daily SWAT model simulation results indicated that temporal rainfall resolution could have much impact on the simulation of hydrological process, streamflow, and consequently pollutant transport by SWAT models. There is an imperative need for more studies to examine the effects of temporal rainfall resolution on the simulation of hydrological and water pollutant transport processes by SWAT in river basins of different environmental conditions. [ABSTRACT FROM AUTHOR]

Vegetation plays an important role in atmospheric, hydrologic and biochemical cycles and is an important indicator of the impact of climate and human factors on the environment. In this paper, a method, which combines the empirical orthogonal function (EOF) and temporal unmixing analysis (TUA) methods, is applied to monitor the phenological characteristcs and spatial distribution of vegetation phenology in the middle part of the Huai River region. Based on the variance and EOF curves, the EOF provides the number of phenology modes, information which is the basis for an accurate temporal unmixing model. The TUA describes the temporal vegetation phenological details and spatial distribution. Importantly, this approach does not require assumptions, prior information or pre-defined thresholds. The vegetation phenology curves derived from the MODIS EVI data using the combined EOF and TUA methods display much more detail than the curves from Landsat TM using spectral mixture analysis (SMA). Additionally, the vegetation phenology spatial distribution from MODIS EVI is consistent with the field survey data. The combination method of EOF and TUA can be used to monitor vegetation phenology spatiotemporal change in a large area from time series of MODIS EVI data. [ABSTRACT FROM AUTHOR]

Abstract: Flooding in the Huai River Basin, China has changed because of climate change and human activity. It is important to determine how flooding has changed and what the main causes of this flood change are. In this study, daily data from 172 precipitation gauges and 1 hydrological station are analysed to detect the changes of precipitation and streamflow over the past 50years in the Huai River Basin. Consequently, a method decomposing the influence of climate change and human activity through a distributed hydrological model is proposed. The time series of the natural streamflow are reconstructed from 1960 to 2009. Inter-annual impacts on the floods of the Huai River Basin are later separated from the impacts of human activity and climate change. Precipitation displays no significant interannual variability but displays great spatial–temporal variability in one year in the Huai River Basin; that is, precipitation is more concentrated in summer and winter in mountainous zones. Flood days in Huai River Basin have increased, whereas the flood peak displays no significant change. This phenomenon may be attributed to reservoir regulation, irrigation and urbanisation water consumption. Moreover, the quantitative assessments reveal that climate change has led to a streamflow increase of 40.8m3/s per year for the Huai River Basin, accounting for 55% of the streamflow change. However, human activity has led to a streamflow decrease of 33.51m3/s per year, accounting for 45% of the streamflow change. The effects of human activity, including water consumption, changes in land cover, and construction of reservoirs and dams, might alter the flooding in the Huai River Basin. [Copyright &y& Elsevier]

Reclaimed water is efficiently used to recover the dry river, but river water and groundwater may be impacted considering the water quality. Thus, it is critical to study the factors controlling water chemistry. Samples of reclaimed water, river and groundwater were collected monthly from January to September in 2010, in Huai River (North China). And samples were analyzed for major 15 physio-chemical parameters. Using hierarchical cluster analysis, 9 months are divided into two distinct groups, which show the clear temporal variation. In reclaimed water and river water, one group includes February, while the other includes other months. In shallow and deep groundwater, one group includes months from January to April, while the other encompasses others. Monitoring stations are classified into three groups. Group A with high value of ions and nitrogen (order: NH-N > NO-N > NO-N) includes reclaimed water and river water. Group B with moderate concentration and nitrogen (order: NO-N > NH-N > NO-N) includes all shallow groundwater and one deep groundwater. Group C with the low value and nitrogen (order: NO-N > NO-N > NH-N), includes two deep groundwater. Using multivariate analysis and ionic relationships, river water chemistry is found to be controlled by reclaimed water and evaporation process; chemistry in shallow groundwater and one deep groundwater, with type of Na-Ca(Mg)-HCO-Cl, is controlled by dissolution of calcite, carbonate weathering. Additionally, reactions of nitrification, denitrification and cation exchange occur in the infiltration of reclaimed water; chemistry in the other deep groundwater, with type of Ca-Mg-HCO-Cl, is controlled by dissolution of calcite, carbonate weathering and denitrification. [ABSTRACT FROM AUTHOR]

Abstract: The Middle Reach of the Huai River (MRHR) flows northeast into the Hongzehu Lake. Before entering the Hongzehu Lake, the Huai River has a braided channel which is shallow and wide, and the riverbed has a negative slope. Based on the characteristics of the MRHR, this river reach can be divided into the following sections: a quasi-straight (or mildly curved) section, a bend section, and a braided section. The majority of the MRHR is quasi-straight. In this paper, several parameters are used to assess the geomorphology of the MRHR. Statistical analyses are performed to establish a relationship between the span length ““L”” and channel width ““B”” for different channel patterns. The relationship between the meandering length ““S”” and bankfull channel width ““B”” is also derived. Results indicate that the bankfull channel width ““B””, the bankfull cross sectional area ““A”” and the average flow depth ““H”” are mainly dependent on the dominant discharge in the channel. A relationship is derived that describes the dependency of the curvature radius ““R”” on the dominant discharge ““Q””, water surface slope ““J”” and the turning angle ““α””. [Copyright &y& Elsevier]

Abstract: Microcystins (MCs) are potent hepatotoxins and have also implicated in liver tumor promotion. The present study investigates the temporal and spatial variations of MCs in different water bodies in the Huai River Basin in China. Water samples including rivers, ponds and wells were collected every quarter during December 2008 and December 2009. MCs were determined by high pressure liquid chromatography after solid phase extraction. MCs concentrations in river samples were 0.741±0.623μgL−1 with maximum of 1.846μgL−1. MCs in pond were 0.597±0.960μgL−1 with maximum of 2.298μgL−1. MCs were also detected in 51.7% of the groundwater samples, MCs in groundwater were 0.060±0.085μgL−1 with maximum of 0.446μgL−1. MCs concentrations in groundwater did not differ significantly among different depths or towns (Wilcoxon test, p> 0.05). The average MCs in groundwater in each sampling period were 0.068μgL−1, 0.118μgL−1, 0.052μgL−1, 0.059μgL−1 and 0.020μgL−1. Through multi linear regression, the best fit model was built on MCs in groundwater with River B (R 2 =0.13, p <0.05), rather than with pond water. The results suggested that MCs contamination in groundwater originated from rivers, causing potential health risk on population who drink groundwater directly. [Copyright &y& Elsevier]

The speciation and distribution of the nutrients nitrogen and phosphorus in riverbed sediment play an important role in river water quality and are the primary product for the river ecosystem. Previous research on river nutrients has not considered the relationship between nitrogen and phosphorus and their mobility effects. To investigate the role of nitrogen and phosphorus in water quality and their interactions between sediments and water, sediment and water samples were taken from 10 sites along the middle main stream of the Huai River in China from Linhuaigang to Fengtai County on December 12, 2008. Nitrogen and phosphorus concentrations in water, organic matter (OM), and different forms and contents of the elements in sediment were investigated. Results showed a positive correlation between total nitrogen in sampled sediments, primarily occupied by organic nitrogen and chlorophyll concentrations in water (). Total phosphorus in sediments was primarily represented as inorganic phosphorus, accounting for 80.9-96.1% of total phosphorus. The concentrations of non-apatite inorganic phosphorus in sediment ranged from . Results from statistical correlation analyses showed that the non-apatite inorganic phosphorus content in sediment was obviously negatively correlated with total nitrogen concentration in water (, ); inorganic nitrogen and non-apatite inorganic phosphorus contents in sediment were positively correlated with total phosphorus and resolvable phosphorus concentrations in water, respectively. Furthermore, data of May 2008 were added and analyzed. The same principles were observed between total nitrogen and non-apatite inorganic phosphorus, total phosphorus and inorganic nitrogen, but a positive correlation was found between (1) total nitrogen in water and (2) exchangeable nitrogen () and inorganic nitrogen () in sediments. [ABSTRACT FROM AUTHOR]

The complete mitogenome sequence of Coilia brachygnathus (Kreyenberg & Pappenheim, 1908) from Wabu Lake in Huai River Basin was annotated and characterized in this study. This mitochondrial genome is a circular DNA molecule of 16.896 bp in size with 57.52% AT content, including 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and an AT-rich region (control region) as other bony fishes. There are a total of 10 overlap locations and 15 intergenic spacer regions throughout the mitogenome of C. brachygnathus . All PCGs employed a standard ATG as a start codon, except cytochrome c oxidase 1 (cox1) with GTG. In addition, TAA or TAG was identified as the typical stop codon. A phylogenetic tree reconstructed with the maximum likelihood method depicted a clone relationship with eight species of genus Coilia and our previous study based on the amino acid sequences of 13 mitochondrial PCGs. The complete mitochondrial genome is a valuable resource in classifying and conserving C. brachygnathus ., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Abstract: Laboratory continuous flow-through riverbank filtration (RBF) models were developed to study the organic substances and ammonia nitrogen removal efficiency in the riverbank filtration process. The results indicated that the priority pollutants, organic substances and ammonia nitrogen, could be removed to a great extent. The results also indicate that the quality of the Huai River water is acceptable to operate the abstraction system with the riverbank filtration. [Copyright &y& Elsevier]

Abstract: Base on the previous study of organic substances and ammonia nitrogen removal efficiency through laboratory continuous flow-through riverbank filtration (RBF) models, field study were carried out to evaluate the results drawn from small model experiments. Five wells were selected to in this riverbank filtration process field study. The results indicated that the priority pollutants, organic substances and ammonia nitrogen, could be removed to a great extent. The results also indicate that the quality of the Huai River water is acceptable to operate the abstraction system with the riverbank filtration. [Copyright &y& Elsevier]