Occurrence of N-nitrosamines and their precursors in the middle and lower reaches of Yangtze River water.

The presence of some types of N-nitrosamines in water bodies is of great concern worldwide due to their carcinogenic risks and harmful mutagenic effects on human health. In the present study, eight N-nitrosamines and their formation potentials (FPs) were primarily investigated in Yangtze River surface water to evaluate their spatial distribution, mass loads, and ecological risks. The results showed that of the eight N-nitrosamines investigated, NDMA (<1.5-17 ng/L), NDEA (<1.4-9.5 ng/L), NDPA (1.0 ng/L), NMOR (<1.0-1.3 ng/L), NPIP (<2.1-3.7 ng/L), and NDBA (<3.6-30 ng/L) were detected. The FPs of NDMA (<27-130 ng/L), NDEA (<0.9-2.3 ng/L), NDPA (<1.2-1.9 ng/L), NPYR (<1.4-2.9 ng/L), NMOR (<1.0 ng/L), and NDBA (<1.1-14 ng/L) were significantly identified. NDBA was predominantly observed in surface water, while NDMA was noticeably detected in chloraminated water samples. It was estimated that approximately 5.4 t/y of N-nitrosamines were carried by the Yangtze River to the East China Sea, whereas the input flux of N-nitrosamine precursors was estimated to be approximately 69.5 t/y. Spatial variations were observed due to the input of N-nitrosamines from the upstream dams and lakes. The origin of N-nitrosamine precursors was not associated with the presence of sediment in river water. NDEA could be introduced into river water by the discharge of wastewater. NDBA and its precursors could originate from industrial and aquaculture activities. NDMA and its precursors could result from both of the aforementioned sources. Moreover, the wastewater discharge from small cities, pH value, wastewater treatment ratio, and dilution could be the key factors that influence the occurrence of N-nitrosamines along the Yangtze River. More attention should be paid to the cancer risks posed by N-nitrosamines. The ecological risks posed by N-nitrosamines in the Yangtze River can be ignored.

[Temporal and Spatial Variation Characteristics of the Heavy Metals Content in the Surface Sediment and the Potential Ecological Risk Trends in the Three Gorges Reservoir Area].

With the construction progress of the Three Gorges Project, the hydrological situation of Three Gorges Reservoir changes greatly, which causes the changes of suspended solids precipitation conditions and surface sediment traits. This research analyzed the temporal and spatial variation of the heavy metal pollution in the surface sediment and the potential ecological risk trends during the years from 2000 to 2015 in the trunk stream of the Yangtze River from Jiangjin to the Three Gorges Dam area and some major tributaries, such as Jialing River, Yulin River, Wujiang River, Xiaojiang River, Xiangxi River. The results showed that the average content ranges of heavy metals (including Cu, Pb, Mn, As, Hg etc.) in surface sediments at the main stream monitoring sections during the study period were 46.5-85.7 mg·kg-1(Cu), 43.8-65.1 mg·kg-1(Pb), 784.2-910.6 mg·kg-1(Mn), 8.44-11.91 mg·kg-1(As), 0.193-0.236 mg·kg-1(Hg) respectively; The average content ranges of the heavy metals in surface sediments at the main stream monitoring sections during the study period were 16.5-85.6 mg·kg-1(Cu), 25.8-74.8 mg·kg-1(Pb), 573.7-996.3 mg·kg-1 (Mn), 6.96-13.31 mg·kg-1 (As), 0.160-0.232 mg·kg-1 (Hg) respectively. The results also showed that there were obvious differences of the heavy metals content in some areas between the left and right bank of the trunk stream of the Yangtze River in the Three Gorges Reservoir area. The results also showed that the concentration variation trends of the heavy metals were different in the surface sediments, such as Cu, Pb, Mn, As and Hg. The content of Hg was the most influenced element by the water period effect. The concentration variation trends of these elements were different at different monitoring sections during the construction and water harvesting progress of the Three Gorges project. The contents of Cu, Pb, Mn and As in sediment from the Three Gorges Reservoir area showed strong positive correlations between each other. But there was a low correlation between the content of As and those of other elements. There was no significant correlation between the content of Hg and those of other heavy metal elements. According to the geoaccumulation index analytical method, the contents of the heavy metals in surface sediments in the Three Gorges Reservoir area were generally at low enrichment level. But the pollution caused by Hg should be paid attention. The change of potential ecological risk index was small in the main stream and the major tributaries of the Yangtze River (except Wujiang River) in most of the time. It should also be noted that the change of potential ecological risk index fluctuated obviously at a high level before the year of 2008, and then the change fluctuations trends descended with time and tended to be stable.

Strengthen the collaboration between the River Basin Management Organization of China and International Environmental Specimen Bank Group.

Several types of emerging organic contaminants were investigated in many recent researches, such as persistent toxic substance (PTS), persistent organic pollutants (POPs), endocrine disrupters (EDs), and volatile organic compounds (VOCs). But the Chinese country standard detection methods of emerging organic pollutants were not developed with the dramatic increasing of the organic substances production. Hence, it is necessary to obtain the latest informations about the long-term storage of representative environmental specimens, which could provide scientific basis for environmental management and environmental decision-making of the water resources protection and management organization. As the significant water resource conservation organization, the Water Environment Monitoring Center of Yangtze River Basin is experienced in water environmental monitoring and records many useful water resources and environment informations. It is also our responsibility to monitor all the pollutants in water environment of the Yangtze River valley, especially the emerging organic contaminants. Meanwhile, the International Environmental Specimen Bank (IESB) accumulates lots environmental organic pollution specimens and plays a significant role in environmental monitoring. Thus, the collaboration between the two parties will be greatly helpful for each further researches and monitoring work of organic contaminants in Yangtze River Basin.

[Distribution characteristics of organochlorine pesticides in bank soil samples and estuarial sediment core of the Minjiang River, Southeast China].

The 19 soil samples and one sediment core were collected from near the banks and in estuary of the Minjiang River. The concentrations of OCPs in the samples were determined by GC-ECD with the internal standard method. The results showed that the concentrations of OCPs, HCHs, DDTs in soils near the banks of Minjiang were in the ranges of 4.31-877.80 ng x g(-1) (with a mean 74.13 ng x g(-1)), 1.32-24.01 ng x g(-1) (7.50 ng x g(-1)), 1.67-876.49 ng x g(-1) (66.64 ng x g(-1)), respectively. Through the study of the vertical distribution characteristics of OCPs in the area, the pollution history of OCPs in the Minjiang estuary was discussed. The concentrations of HCHs and DDTs in the core ranged from 0.34-11.72 ng x g(-1) and 1.12-31.04 ng x g(-1), respectively. The results also showed that the soils and cores in the area have polluted lightly by DDTs, but not been polluted by HCHs. Upper section of the sediment core, o ,p'-DDT was the main composition, which indicated that new DDTs may be still used recently in the Minjiang area. The vertical changes of OCPs reflected basically their production and application history in banks of Minjiang River, Fujian Province.

Organochlorine pesticides (OCPs) in soils and sediments, southeast China: A case study in Xinghua Bay.

This study evaluated the contamination status and distribution of organochlorine pesticides (OCPs) between Xinghua Bay and adjacent watersheds in Putian region, southeast China. Twenty-five surface soil samples and two sediment cores were collected from two watersheds and the Xinghua Bay, respectively. Results showed that the concentrations of OCPs in samples of the Mulan River Watershed (MRW), the Qiulu River Watershed (QRW), the inner bay core (IBC) and the open bay core (OBC) were in the range of 4.96-38.20ng/g, 4.62-22.80ng/g, 1.84-80.46ng/g and 1.87-23.43ng/g, respectively. The mean concentration of OCPs was in an order: IBC>MRW>QRW>OBC. The higher concentration of OCPs in recent periods may suggest that a certain amount of OCPs were still input to this area.