Polychlorinated biphenyls (PCBs) were produced in the mid 1900s for industrial use. The term PCBs refers to 209 theoretically possible chlorinated compounds of the biphenyl molecule (congeners). The number and location of the chlorines govern both the environmental fate and toxicity of each congener. Changes in the distribution of congeners in river sediments can result from congener transformation and/or preferential congener transport. This study exploits the distribution of PCB congeners, specifically congeners that maintain a constant ratio relationship in the commercially manufactured PCB mixtures (Aroclors), to quantify the likelihood of congener distribution shifts in river sediment. By using relative abundances, the influence of total PCB bias is eliminated. Correlated congeners (tracker pairs) maintain a constant relative proportion in sequentially more-highly chlorinated Aroclors, thus there is no need to know the source contaminating Aroclors a priori. Using the Frame et al. database of Aroclor congener distributions, 276 pairs of correlated congeners, constructed from 95 individual congeners, are identified. A comparison study of Aroclors and Hudson River sediments included 218 of the 276 tracker pairs. Conclusive evidence of a shift in the congener proportions is found in 120 of the 218 cases, a much greater number than expected if no change in congener distribution had occurred.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/es0494149 | DOI Listing |
J Environ Manage
January 2025
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address:
Microplastics (MPs) are ubiquitous in aquatic environments, threatening the security of aquatic organisms. Identifying the emission node and hot spot of MPs holds significant importance in the pollution control of MPs. Wastewater is widely recognized as sink and source of MPs, while the direct evidence is insufficient.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Laboratorio de Investigaciones Ambientales, Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad, 1001, Col. Chamilpa, Cuernavaca C.P. 62209, Morelos, Mexico.
Water pollution by metals is a global environmental problem. In riparian ecosystems, metal pollution generates adverse effects on organisms and reduces water quality. The Cuautla River is of great ecological relevance and an important water supplier.
View Article and Find Full Text PDFPlants (Basel)
December 2024
School of Professional Studies Huasteca Zone, Autonomous University of San Luis Potosí, Ciudad Valles, San Luis Potosí 79060, Mexico.
The contamination of rivers by potentially toxic elements (PTEs) is a problem of global importance. The Valles River is Ciudad Valles' (Central Mexico) main source of drinking water. During the four seasons of the year, water samples (n = 6), sediment samples (n = 6), and plants (n = 10) were taken from three study sites selected based on the presence of anthropogenic activities in the Valles River.
View Article and Find Full Text PDFSci Rep
January 2025
Geochronology and Tracers Facility, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK.
Loess profiles along the Danube River provide a record of long-term Quaternary dust (loess) deposition in central-eastern Europe. Here, Sr-Nd isotopic data from four loess-palaeosol profiles (47 samples) spanning the last two-glacial-interglacial cycles are presented. The isotopic compositions generated by this study are compared with bedrock and sedimentary samples from Europe and North Africa to decipher the sources of sediment.
View Article and Find Full Text PDFEnviron Res
January 2025
MNR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China.
The occurrence of heavy metals is important for understanding their behavior in the sediments of river-salt lake ecosystems due to dramatically changes in salinity and flow velocity at the confluence area. Sediments and surface water samples were collected from the Golmud River-Dabson Salt Lake ecosystem, northwest China, to investigate the spatial distribution, sediment-water partitioning, risk assessment and source apportionment of heavy metals. Higher concentrations of heavy metals were observed in surface water from Dabson Salt Lake than in other regions.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!