Surface water pathways and fluxes of metals under changing environmental conditions and human interventions in the Selenga River system

2016 ◽  
Vol 76 (1) ◽  
Author(s):  
M. Lychagin ◽  
S. Chalov ◽  
N. Kasimov ◽  
G. Shinkareva ◽  
J. Jarsjö ◽  
...  
2020 ◽  
Vol 13 (1) ◽  
pp. 80
Author(s):  
Yulia A. Frank ◽  
Egor D. Vorobiev ◽  
Danil S. Vorobiev ◽  
Andrey A. Trifonov ◽  
Dmitry V. Antsiferov ◽  
...  

To date, the largest Russian rivers discharging to the Arctic Ocean remain a “blank spot” on the world map of data on the distribution of microplastics in freshwater systems. This study characterizes the abundance and morphology of microplastics in surface water of the Ob River and its large tributary, the Tom River, in western Siberia. The average number of particles for the two rivers ranged from 44.2 to 51.2 items per m3 or from 79.4 to 87.5 μg per m3 in the Tom River and in the Ob River, respectively. Of the recovered microplastics, 93.5% were less than 1 mm in their largest dimension, the largest group (45.5% of total counts) consisted of particles with sizes range 0.30–1.00 mm. Generally, microfragments of irregular shape were the most abundant among the Ob and Tom samples (47.4%) and exceeded microfibers (22.1%), microfilms (20.8%), and microspheres (9.74%) by average counts. Results from this study provide a baseline for understanding the scale of the transport of microplastics by the Ob River system into the Arctic Ocean and add to currently available data on microplastics abundance and diversity in freshwater systems of differing global geographic locations.


Water ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 580 ◽  
Author(s):  
Mariusz Ptak ◽  
Mariusz Sojka ◽  
Adam Choiński ◽  
Bogumił Nowak

Author(s):  
Oanh Doan Thi ◽  
Thuy Duong Thi ◽  
Huong Nguyen Thi Nhu ◽  
Quynh Hoang Thi ◽  
Quynh Le Thi Phuong ◽  
...  

Microplastics (MPs), referring to plastic items ranging from 1 to 5000 µm long, are polluting the terrestrial and aquatic environments and are becoming a threat to the health of ecosystems, biota, and humans. Rivers are major carriers of these materials from the terrestrial environment to the oceans. In the present study, the occurrence of MPs in a peri-urban river was investigated. The Day river system is a good example of a peri-urban river strongly influenced by human activities in the whole basin. Water samples were collected from the downstream of the Day river, including Cau Que, Cau Do, and Do Thong, in the rainy and dry seasons using a plankton sampling net for identifying microplastic concentration, size, shape, color, and polymer composition. Microplastic abundance in the surface water ranged from 269,693±60,624 to 863,005±131,925 items/m3. The microplastic concentration in the rainy season was higher than that in the dry season. MPs abundance was increased at a site near urban areas with high human activity. The microplastic shape was collected in different seasons did not change significantly, with microplastic fibers as the major items, accounting for above 92% of the total items. Many fibers microplastics collected in this study were in small sizes of 300-1000 µm and 1000-2000 µm, occupying 78.5-85.7% of the total microplastic items. Purple was the most common color of microplastics. Polyethylene (PE) and polypropylene (PP) were major polymer types of the selected items in the surface water samples downstream of the Day River.


2019 ◽  
Vol 17 (3) ◽  
pp. 257-268
Author(s):  
Liswara NENENG ◽  
Rudy Agung NUGROHO ◽  
Yukio KOMAI ◽  
Naru TAKAYAMA ◽  
Koji KAWAMURA

Urbanization has affected natural freshwater environments by contamination with sewage, toxic chemicals, and excess nutrients, which cause algal bloom, pollution, and ecosystem degradation. To ensure sustainable use of natural waters, appropriate monitoring methods are required. This study aims to investigate the diversity of the microbial community in a metropolitan river system in Japan using a low-cost DNA-based approach, PCR (Polymerase Chain Reaction)-RFLP (Restriction Fragment Length Polymorphism), as a potential bioindicator of environmental change. Surface waters were sampled in seven sites in a river system. Water chemical parameters and concentrations of heavy metals were determined. Microbial DNA was extracted from the samples, ribosomal RNA was amplified with universal primers, and RFLP was scored by agarose gels. Water chemical analyses showed that surface water at the inflow point of a sewage treatment plant had signs of eutrophication. Heavy metal concentrations in surface water were low (< 0.01 ppm) in all sites. The PCR-RFLP analysis showed polymorphisms both in 16S and 18S rRNAs, indicating that the method can detect at least a part of the microbiome changes in a river system. Sequencing of some fragments found the sequence close to a ciliate isolated in wastewater treatment plants, implying contamination from sewage. Principal component analysis (PCA) identified the RFLPs associated with chemical water parameters, which could be bioindicators of environmental pollution. We also found the RFLPs independent of water quality parameters, suggesting that this simple DNA-based analysis can also detect biological changes in water ecosystems that are not quantified by chemical measurements of water quality.


2014 ◽  
Vol 22 (4) ◽  
pp. 2856-2867 ◽  
Author(s):  
Bulat Nadmitov ◽  
Seongjin Hong ◽  
Sang In Kang ◽  
Jang Min Chu ◽  
Bair Gomboev ◽  
...  

2007 ◽  
Vol 97 (4) ◽  
pp. 421-428 ◽  
Author(s):  
A. J. Gevens ◽  
R. S. Donahoo ◽  
K. H. Lamour ◽  
M. K. Hausbeck

Phytophthora capsici infects cucurbitaceous and solanaceous crops worldwide. In free water, P. capsici sporangia release zoospores that may be disseminated by moving surface water. Surface irrigation sources (river system, ponds, and ditches) in three Michigan counties with a history of P. capsici-susceptible crop production were monitored for the pathogen during four growing seasons (2002 to 2005). Pear and cucumber baits were suspended in water at monitoring sites for 3- to 7-day intervals and water temperature was recorded. Baits were washed and lesions were excised and cultured on water agar amended with rifampicin and ampicillin. P. capsici was detected at monitoring sites in multiple years, even when non-host crops were planted nearby. Recovered isolates (N = 270) were screened for sensitivity to the fungicide mefenoxam and characterized for mating type (MT). P. capsici isolates resistant to mefenoxam were common in water sources from southwest and southeast Michigan. Most monitoring sites yielded isolates of a 1:1 ratio of A1:A2 MTs. Amplified fragment length polymorphism analysis of select isolates from 2002 to 2004 indicated a lack of similarity groups persisting over time and in specific geographical locations. Data suggest that P. capsici did not overwinter in any of the surface water sources monitored. Water temperatures were correlated to positive P. capsici detection from all monitoring sites. The frequent detection of P. capsici in surface water used for irrigation in the primary vegetable growing regions in Michigan suggests that this is an important means of pathogen dissemination.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yi Bao ◽  
Changqing Xu ◽  
Qinwen Zhu ◽  
Yuesheng Li

Abstract“Alteration” geologically refers to chemical composition and/or structural changes of minerals under the influences of hydrothermal fluids, surface water, seawater, or other environmental conditions. In this paper, we use the word “alteration” to refer to chemical component and structural changes in jade artifacts caused by human activity and natural weathering, which is different from the term in geology. “Mercury alteration”, a kind of black alteration related to Hg, is unique among the several types of alteration that occur in Chinese ancient jades. Mercury alteration often appears on ancient jade artifacts unearthed from high-grade tombs of the pre-Qin period (before 221 B.C.). Therefore, ancient jades with mercury alteration have attracted substantial attention from Chinese archaeologists. This paper reports the use of materials analytic techniques to study such ancient jade fragments. The studied jade samples date to the middle and late periods of the Spring and Autumn Period (~500 B.C.) and were unearthed from Lizhou’ao Tomb in Jiangxi Province, China. Structural analyses revealed the internal microstructure of the ancient jade fragments and the microdistribution of the mercury alteration. The jade fragments exhibit typical characteristics of round holes and structural hierarchy, which imply that the jades were heated before burial. The black alteration on these jade samples was found to be rich in Hg. The results of this study will be widely useful in the study of ancient jade artifacts and jade culture in Chinese archeology.


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