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As an indispensable type of pesticide, fungicides have been somewhat neglected compared to insecticides and herbicides. Heavy fungicide application in agricultural regions may generate downstream ecological concerns via in-stream transport, and the reservoir complicates the process. Monitoring fungicide exposure and exploring reservoir effect on fungicide transport is the key to develop the downstream strategies of agricultural diffusion pollution control. Here, we investigated the exposure, spatiotemporal dynamics, and ecological risk of fungicides in a reservoir-regulated agricultural basin, located in the middle of the Yangtze River Basin, China. Seven fungicides were preliminarily identified and exhibited high detection frequencies (85 %) in subsequent quantification of water samples from three sampling activities. The total concentration of fungicides ranged from 2.47 to 560.29 ng/L, 28.35 to 274.69 ng/L, and 13.61 to 146.968 ng/L in April, September, and November, respectively. Overall, the contamination levels of fungicides were in the ascending order of April November September. The spatial distribution of fungicides was closely associated with the dense of cultivated land, supporting its agricultural source. Furthermore, the reservoir plays a retention role in fungicides, alleviating ecological pressure downstream during the water storage period. Yet, due to the alternation of "source" and "sink" function of the reservoir, the contribution of Zijiang River to the fungicide load in the Yangtze River Basin still needs further attention. Although there is no acute risk posed by fungicides, even in the high-exposure scenario, the chronic ecological risk could not be ignored. Agricultural intensive regions, coupled with the reservoir, provide rather substantial chronic ecological concerns. Carbendazim has been designated as a priority pollutant that contributes significantly to cumulative chronic risk. Thus, we emphasize strengthening the supervision of fungicides in surface water and rationally restricting the use of carbendazim in agricultural operations.

Under the environmental changes associated with mine tributaries entering mainstream rivers, differences in the distributions and migration behaviors of metal(loid)s can be found, but the behavior of antimony (Sb) is still poorly understood in this regard. We analyzed the occurrence, distribution, migration, and influencing factors of the Sb concentration in the water body of the Zijiang River (ZR) around a superlarge Sb deposit zone. The total Sb concentrations were 1.45-15.66 μg/L, 3.16-133.63 mg/kg, and 0.83-41.82 μg/L in the ZR surface waters, sediments, and pore waters, respectively; Sb(V) was the predominant form of Sb found in the surface waters. Mining and smelting were the main sources of Sb in the ZR. Spatially, the Sb concentration showed a decreasing trend from the tributaries to the ZR mainstream. In the ZR, the surface-water Sb concentration showed an increasing trend from the upstream to the downstream, while in the sediments and pore waters, the midstream Sb concentrations were higher than the upstream and downstream concentrations; this finding was related to the sediment retention and accumulation behaviors of reservoirs and dams resulting in the secondary release of Sb in sediments. Sb tended to be bound to the solid phase, dominated by amorphous iron (Fe)/aluminum (Al) oxides and calcium in sediments. This study highlights that, based on current Sb migration patterns, the accumulation of sediments carried by tributaries near Sb mines in the midstream ZR and the Sb pollution caused by sediment release will be long-term, and the related environmental consequences need to be further predicted.

Simulating the adsorption behavior of Sb(V) on goethite is of great significance for predicting the mobility of Sb(V) in soil. However, there is still a lack of charge distribution and multisite surface complexation (CD-MUSIC) models that conform to the actual adsorption mechanism. Therefore, our research combined the previous EXAFS results with the SCMs and established two CD-MUSIC models (Model I, which introduced bidentate binuclear and bidentate mononuclear complexes, and Model II, which introduced bidentate mononuclear and monodentate mononuclear complexes). It is also one of the rare cases that bidentate edge- and corner-sharing adsorption complexes have been distinguished by introducing different amounts of H

Pollution of potentially toxic metals (PTMs) in road dust (RD) is becoming an important threat to the urban environmental quality and human health. The chemical speciation of PTMs is an important index charactering the risks, which may also closely relate to the pollution level and source but it was poorly understood. In this study, the chemical speciation of Cd, Cr, Cu, Ni, Pb and Zn in the RD of a megacity (Nanjing), China was determined following an optimized BCR (proposed by the European Community Bureau of Reference) sequential extraction procedure to assess their pollution and potential eco-risk and to explore the variations of metal chemical speciation with the pollution levels and sources. Total concentrations of the PTMs in the RD were enriched 1.4- to 123-fold relative to the subsoil with median contamination factors (CF) of 6.7 (Pb), 6.0 (Cu), 5.5 (Cd), 4.0 (Zn), 2.0 (Cr) and 1.9 (Ni). Pollution of the PTMs should be mainly from industrial and traffic emissions and showed high CF values in the northern industrial zone. Whereas, the chemical percentages of each metal showed relatively narrow spatial variations and were not statistically correlated with the pollution levels (p = 0.05). Comparing of similar studies indicates that no regular patterns existed in chemical percentages for each metal in RD polluted by the traffic and/or both the industrial and traffic sources. In the RD of Nanjing, Pb was mostly associated with reducible phase, Cd and Zn were mainly present in acid-soluble phase, Cu was mostly concentrated in oxidizable phase, while Cr and Ni were predominantly present in residual phase. As the typical pollutants, anthropogenic Cd, Cu, Pb and Zn were mostly associated with the potential mobile phases but also with the residual phase in the RD of Nanjing, causing 1.4- to 3.0-fold increase in the mobility. Combining the assessments from eco-risk index, risk assessment code and sediment quality guidelines with the pollution levels and chemical speciation, we deduced that Cd, Cu, Pb and Zn may pose certain eco-risk upon transport into the aquatic system and soil, and Cd should be primarily concerned.

Tench, Tinca tinca (L.) was introduced as a new species to Chinese aquaculture in 1998. Biological characteristics of tench are studied, and propagation techniques are improved at the Hubei Province Fisheries Institute with co-operation with the Research Institute of Fish Culture and Hydrobiology in Czech Republic and Institute of Hydrobiology, Chinese Academy of Sciences. The first successful artificial propagation of tench in China was made in 2000. The number of produced tench larvae increased from 5 millions in 2001 to 20 millions in 2002, and to 200 millions in 2003. The number of juveniles >5 cm reached 12 millions in 2002 and 120 millions in 2003. Total area of ponds with tench culture was 1400 ha in 2002 and 5400 ha in 2003. Main problems that hinder development of tench culture in China are identified, and future prospects of tench farming in China are highlighted. Abundant water bodies for aquaculture and cheap man-power make the export of tench from China to Europe, USA, Australia and Korea a promising activity.

Effects of the starting time and duration of cold shock, as well as the source of heterogenic sperm on the percentage of viable gynogenic larvae (PVGL) in tench were studied. The DNA in sperm of red common carp (Cyprinus carpio var singuonensis) was inactivated by ultraviolet radiation prior to use to induce meiotic gynogenetic development in tench. In experiment 1, tench eggs were cold-shocked for 30 min starting at 1, 3, 5, 7, 10 and 15 min post activation. In experiment 2, cold shock began 5 min after activation and lasted for 10, 20, 30, 40, 50 min, respectively. Each experiment was run in triplicate using 3 tench females, and one group not treated with cold shock was included in each experiment to serve as a control group. In experiment 3, sperm of bigmouth buffalo (Ictiobus cyprinellus), red common carp or grass carp (Ctenopharyngodon idella) was used to induce gynogenesis in tench with a 20-min cold shock starting 5 min post activation. The results showed that PVGL from the control group was very low (0.11-0.47%). In experiment 1, the highest average PVGL (9.60%) was observed when cold shock treatment was applied 5 min post activation. When cold shock treatment was started 5 min post activation, duration of cold shock affected PVGL. Cold shock lasting 20 min resulted in the highest average PVGL (12. 57%) among the selected duration of cold shock studied in experiment 2. The average PVGL was 2.3, 8.6, and 9.3%, respectively, for eggs induced by sperm of bigmouth buffalo, red common carp and grass carp. Average PVGL was significantly lower for eggs induced by sperm of bigmouth buffalo, compared with that for eggs induced by sperm of the other two species. However, average PVGL were similar for eggs induced by sperm of red common carp and grass carp. In summary, the optimal conditions for gynogenesis in tench include the use of irradiated sperm of grass carp to activate the eggs and cold shock of 20 min starting 5 min post activation. Since female tench grow much faster to a larger size than male tench, gynogenesis of tench holds great potential for production enhancement.