Occurrence and distribution of antibiotics and antibiotic resistant genes in water and sediments of urban rivers with black-odor water in Guangzhou, South China.

Distribution, contamination and source identification of heavy metals in bed sediments from the lower reaches of the Xiangjiang River in Hunan province, China

Heavy metal pollution, ecological risk, spatial distribution, and source identification in sediments of the Lijiang River, China.

The Xiangjiang River is an important drinking water resource for the Hunan Province of China. It is crucial to ascertain the pollution status, influencing factors, ecological risks, and possible sources of heavy metals in the sediments of the Xiangjiang River. Sediment is both a source and a sink of heavy metals in aquatic ecosystems. In this study, surface sediment was collected from the Zhuzhou Reach of the Xiangjiang River and eight heavy metals were investigated. In all sediment samples, all eight heavy metals were detected and their average concentration fell in the order of Zn > Pb > As > Cu > Cr > Ni > Cd > Co. Assessment shows extremely serious Cd pollution and a very high potential ecological risk from Cd. According to correlation analysis and principal component analysis (PCA), As, Cu, Ni, Pb, and Zn originate from industrial wastewater and mineral smelting activities, whereas Co, Cr, and Ni come from natural sources. Redundancy analysis (RDA) reveals that the organic matter content and the particle size of the sediment have a certain influence on the enrichment of heavy metals. Among all eight examined heavy metals in the surveyed area, the content of Zn, Pb, and As is the highest, and that of Cd and Co is the lowest. Despite a low level of absolute content, the Cd in sediment already renders a high ecological risk and thus calls for urgent attention. Anthropogenic activities are the main source of heavy metals in the sediment. The distribution of heavy metals may also be influenced by sediment properties. The results provide guidance for controlling heavy metal pollution and protecting drinking water sources in the Xiangjiang River.

https://link.springer.com/content/pdf/10.1186/s12302-020-00305-w.pdf

Risk assessment of heavy metals in the surface sediment at the drinking water source of the Xiangjiang River in South China

Seven heavy metals (Cr, Mn, Co, Ni, Cu, Zn, Pb) were measured in surface sediments from the Lishui River watershed, an area with increased soil erosion in China. The mean concentrations of heavy metals were 61.20 mg/kg (Cr), 757.15 mg/kg (Mn), 9.39 mg/kg (Co), 25.31 mg/kg (Ni), 22.84 mg/kg (Cu), 91.66 mg/kg (Zn), and 40.19 mg/kg (Pb), respectively. The spatial distribution of heavy metals was site-specific, exhibiting a remarkably high level in the sampling stations with intense agricultural activities (Lixian) and industrial activities (Jinshi). Contamination indexes including contamination factor, pollution load index, nemerow multi-factor index, potential ecological risk index, and human health risk were used to assess the pollution degree of the river sediments. The results indicated the pollution degree of heavy metals decreased in the order of Mn > Pb > Zn > Cr > Cu > Ni > Co. Heavy metals resulted in non-pollution to moderate pollution, with low ecological risk and an acceptable carcinogenic risk caused by Cr and Ni for children and adults. Person’s correlation analysis and principal component analysis, coupled with cluster analysis, revealed that the sediments from the Lishui River were mainly influenced by two sources. Cr, Co, Ni, and Cu were mainly derived from natural sources, while Mn, Zn, and Pb originated from agricultural and industrial activities, mining, and vehicular traffic.

Contamination Evaluation and Source Identification of Heavy Metals in the Sediments from the Lishui River Watershed, Southern China

The sediment pollution caused by heavy metals has attracted a great deal of attention due to its persistence, bioaccumulation and toxicity. This research was the first to consider the whole of South China to obtain an overall profile of heavy metal spatial distribution, possible sources and pollution levels in river systems. For these data, 14 selected heavy metals were analysed in river sediments collected from sampling sites in Guangdong, Fujian, Guangxi and Hainan Provinces. The geoaccumulation index and enrichment factor revealed that river systems in South China were universally contaminated by Cd, As and Sn, which might be distributed by anthropogenic activities. Moreover, Guangdong Province, a relatively developed area in South China, was relatively polluted by certain heavy metals such as Ni, Cu, Zn and Mn. Multivariate statistical analyses such as Pearson's correlation matrix and a principal component analysis determined that several of the heavy metals might be derived from similar anthropogenic activities such as industrial effluents and domestic sewage discharge. In terms of heavy metal contamination in South China, necessary measures should be undertaken to protect rivers in South China.

Distribution, source and pollution level of heavy metals in river sediments from South China

The U-series and Pu isotope signatures in the environment have emerged as important tools for promoting geochemical studies. To enhance the understanding of U and Pu sources and behaviours in river systems, this study examined 234U, 235U, 236U, 238U and 239Pu, 240Pu isotopes in surface sediments collected from the Yangtze River catchment and estuary in China, for the first time. The 234U, 235U, 238U and 236U concentrations were measured in the range of 8.29–20.6 Bq/kg, 0.352–0.789 Bq/kg, 7.39–16.4 Bq/kg and (3.05–21.1) × 107 atoms/g. Additionally, the 236U/238U, 234U/238U and 235U/238U atom ratios were in the range of (1.43–6.85) × 10−8, (6.08–7.01) × 10−5 and (7.49–8.08) × 10−3 respectively. For all samples, the 239+240Pu activity concentrations ranged from 0.01 to 3.40 Bq/kg. In the Yangtze River catchment, 240Pu/239Pu atom ratios presented typical global fallout values (0.168–0.201); while in the Yangtze River estuary, higher values of 0.216–0.264 located between global fallout and PPG (Pacific Proving Grounds) close-in fallout values. From west to east, the 234U, 235U, 236U and 238U activities generally exhibited decreasing trend from the upstream parts of the river to the estuary. The values of 236U concentrations and 236U/238U, 240Pu/239Pu, 236U/239Pu atom ratios located in the range of global fallout level in environmental samples from other regions, therefore, it may be concluded that 236U in surface sediments of the Yangtze River catchment and estuary are mainly derived from global fallout.

Uranium and plutonium isotopes and their environmental implications in surface sediments from the Yangtze River catchment and estuary

To investigate the distribution and source of plutonium in the northern South China Sea, surface sediments, including samples from the shore, shelf, slope, and Pearl River estuary, were collected t...

Zhiyong Liu

Papers

Distribution, source and pollution level of heavy metals in river sediments from South China

Uranium and plutonium isotopes and their environmental implications in surface sediments from the Yangtze River catchment and estuary

Identification of the Distribution and Sources of Pu in the Northern South China Sea: Influences of Provenance and Scavenging