Land-Use-Based Sources and Trends of Dissolved pPBDEs and PAHs in an Urbanized Watershed Using Assive Polyethylene Samplers

Narragansett Bay is a temperate estuary on the Atlantic coast of Rhode Island in the north-eastern United States, which receives organic pollutants from urban and industrial activities in its watershed, though detailed knowledge on sources and fluxes is missing. Twenty-four polyethylene passive samplers were deployed in the surface water of the watershed around Narragansett Bay during June-July of 2014, to examine the spatial variability and possible sources of priority pollutants, namely dissolved polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). Dissolved ∑22PAH concentrations ranged from 3.6 to 340 ng L-1, and from 2.9 to 220 pg L-1 for ∑12PBDE. The spatial variability of the concentrations was correlated to land use pattern and population distribution, in particular with human activities within 2 km of sampling sites. River discharges derived from the concentrations of PAHs and PBDEs measured here were 10-20 times greater than their previously measured concentrations in the open waters of Narragansett Bay. These results imply that river waters are the main source of PAHs and PDBEs to the Bay and that major sink terms (e.g., sedimentation, degradation) affect their concentrations in the estuary. Predicted PAH and PBDE toxicity based on dissolved concentrations did not exceed 1 toxic unit, suggested that no toxicity occurred at the sampling sites

Net volatilization of PAHs from the North Pacific to the Arctic Ocean observed by passive sampling

The North Pacific-Arctic Oceans are important compartments for semi-volatile organic compounds’ (SVOCs) global marine inventory, but whether they act as a “source or sink” remains controversial. To study the air-sea exchange and fate of SVOCs during their poleward long-range transport, low-altitude atmosphere and surface seawater were measured for polycyclic aromatic hydrocarbons (PAHs) by passive sampling from July to September in 2014. Gaseous PAH concentrations (0.67–13 ng m−3) were dominated by phenanthrene (Phe) and fluorene (Flu), which displayed an inverse correlation with latitude, as well as a significant linear relationship with partial pressure and inverse temperature. Concentrations of PAHs in seawater (1.8–16 ng L−1) showed regional characteristics, with higher levels near the East Asia and lower values in the Bering Strait. The potential impact from the East Asian monsoon was suggested for gaseous PAHs, which – similar to PAHs in surface seawater - were derived from combustion sources. In addition, the data implied net volatilization of PAHs from seawater into the air along the entire cruise; fluxes displayed a similar pattern to regional and monthly distribution of PAHs in seawater. Our results further emphasized that air-sea exchange is an important process for PAHs in the open marine environments

Legacy halogenated organic contaminants in urban-influenced waters using passive polyethylene samplers: Emerging evidence of anthropogenic land-use-based sources and ecological risks

Legacy halogenated organic pollutants, including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), remain ubiquitous in the environment and continue to pose potential (eco-)toxicological threats because of their ongoing releases from land-based sources. This study investigated the spatial trends of freely dissolved PCBs and OCPs by polyethylene passive samplers, and provided evidence of their land-use-based sources and ecological risk in an urbanized estuary area of Narragansett Bay. Dissolved Σ29PCB concentrations ranged from 0.01 to 1.37 ng L−1, and exhibited higher concentrations in the upper, more urban/built-up watershed, and in north coastal areas. Major inputs of PCBs were urban stormwater or treated wastewater that might carry past releases of Aroclors, pigment manufacturing byproducts, and volatilization-associated PCBs from ageing buildings from the Narragansett watershed to the bay. The dioxin toxicity equivalent values of Σ5PCBs were 8.6E-03 pg L−1 in water. Dissolved OCP concentrations had similar spatial trends to PCBs and were dominated by DDTs (average 230 pg L−1), followed by chlordanes (average 230 pg L−1), and HCB (average 22 pg L−1). Secondary sources of past usage and historic contamination were expected to re-enter the surface water via atmospheric transport and deposition. The risk quotients of DDE, DDD, DDT and α-Endosulfane showed medium to high ecological risks in the northern area, while chlordane, HCB, oxychlordane, and heptachlor epoxide showed low to negligible risks in all zones. This study presented new insights into the presence, sources and transport of legacy halogenated organic contaminants in an urban estuary\u27s watershed by combining passive samplers and geographic information system (GIS) technology. The approach is promising and could be extended to get better understand of terrestrial pollutant mobilization into estuaries affected by anthropogenic activities

Baseline of Pollution of Heavy Metals and Physico-chemical Parameters in Surface Sediments from Quanzhou Bay, China, in 2006-2007

According to the monitoring results of the near-shore sediments of Quanzhou Bay in 2006-2007, we analyzed the near-shore depositional environmental quality of Quanzhou Bay and assessed it by the single-factor evaluation on the basis of corresponding standards of local marine functional areas. The results showed that the sediments from the inner part of Quanzhou Bay were polluted more seriously than that of the open part, which might be due to the increasing human activities in coastal areas. The main exceeding standard items are petroleum, Cu, Zn and Pb. In additions, the pollutions caused by sulfide and Cr are different in different regions. The contents of Hg and As are basically in according with the sedimentary quality standards of the corresponding marine functional areas. According the evaluating results, we also provided the corresponding measures to control the pollutions in sedimentary environment of Quanzhou Bay. (C) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of National University of Singapore

Pervasive hybridization during evolutionary radiation of Rhododendron subgenus Hymenanthes in mountains of southwest China

Radiations are especially important for generating species biodiversity in mountainous ecosystems. The contribution of hybridization to such radiations has rarely been examined. Here, we use extensive genomic data to test whether hybridization was involved in evolutionary radiation within Rhododendron subgenus Hymenanthes, whose members show strong geographic isolation in the mountains of southwest China. We sequenced genomes for 143 species of this subgenus and 93 species of four other subgenera, and found that Hymenanthes was monophyletic and radiated during the late Oligocene to middle Miocene. Widespread hybridization events were inferred within and between the identified clades and subclades. This suggests that hybridization occurred both early and late during diversification of subgenus Hymenanthes, although the extent to which hybridization, speciation through mixing-isolation-mixing or hybrid speciation, accelerated the diversification needs further exploration. Cycles of isolation and contact in such and other montane ecosystems may have together promoted species radiation through hybridization between diverging populations and species. Similar radiation processes may apply to other montane floras in this region and elsewhere

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure