This study aims to assess the spatial patterns of selected dust-borne trace elements alongside the river Indus Pakistan, their relation with anthropogenic and natural sources, and the potential risk posed to human health. The studied elements were found in descending concentrations: Mn, Zn, Pb, Cu, Ni, Cr, Co, and Cd. The Index of Geo-accumulation indicated that pollution of trace metals were higher in lower Indus plains than on mountain areas. In general, the toxic elements Cr, Mn, Co and Ni exhibited altitudinal trends (P < 0.05). The few exceptions to this trend were the higher values for all studied elements from the northern wet mountainous zone (low lying Himalaya). Spatial PCA/FA highlighted that the sources of different trace elements were zone specific, thus pointing to both geological influences and anthropogenic activities. The Hazard Index for Co and for Mn in children exceeded the value of 1 only in the riverine delta zone and in the southern low lying zone, whereas the Hazard Index for Pb was above the bench mark for both children and adults (with few exceptions) in all regions, thus indicating potential non-carcinogenic health risks. These results will contribute towards the environmental management of trace metal(s) with potential risk for human health throughout Pakistan.

Surface soil samples were collected surrounding two brominated flame retardants (BFRs) manufacturing plants in China in August 2014 and analyzed for 23 polybrominated diphenyl ethers (PBDEs) and 8 novel brominated flame retardants (NBFRs). BDE209 and decabromodiphenylethane (DBDPE) were the predominant compounds in soil with the median levels of 1600 and 560 ng/g dw, respectively. The PBDEs profiles in soil samples were consistent with that of commercial product (comDecaBDE). The percentage contributions to total PBDEs decreased from higher to lower brominated homologues. Lower concentrations of NBFRs (excluding DBDPE) were detected in soil surrounding the two plants, suggesting they are byproducts or degradation products of the manufacturing activities. The concentrations of most BFRs dropped exponentially within 3–5 km of the manufacturing plants, suggesting recent deposition of these compounds to the soil. Directional distribution indicated that PBDEs and DBDPE concentrations were highest in the north direction of Plants 1. Three-day air parcel forward trajectories confirmed that the air parcel was responsible for the higher concentration of BFRs in the soil of north direction of the plant.

CicLAvia in Los Angeles, CA is the open streets program that closes streets to motorized vehicles and invites people to walk, run, play or ride their bicycles on these streets, allowing them to experience the city in a new way and get exercise at the same time. Since the events reduce the motorized traffic flow, which is a significant source of air pollution, on the streets, it is reasonable to hypothesize that the CicLAvia events can reduce the concentrations of traffic-emitted air pollutants during the road closure. This study is the first experiment to test this hypothesis. The on-road and community-wide ultrafine particle (UFP) and PM2.5 were measured on the Event-Sunday (October 5th, 2014) and the Pre- and Post- Sundays (September 28ᵗʰ and October 12ᵗʰ, 2014). Data analysis results showed the on-road UFP and PM2.5 reduction was 21% and 49%, respectively, and the community-wide PM2.5 reduction was 12%.

In this study, PCB-153 bioaccumulation kinetics and concentration-response experiments were performed employing wild Mytilus galloprovincialis mussels. In addition, the activity of three enzymatic biomarkers: glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE), were measured in the mussel gills. The experimental data fitted well to an asymptotic accumulation model with a high bioconcentration factor (BCF) of 9324 L kg−1 and a very limited depuration capacity, described by a low excretion rate coefficient (Kd = 0.083 d−1). This study reports by first time in mussels significant inhibition of GST activity and significant induction of GPx activity as a result of exposure to dissolved PCB-153. In contrast, AChE activity was unaffected at all concentrations and exposure times tested. The effects on both enzymes are time-dependent, which stresses the difficulties inherent to the use of these biomarkers in chemical pollution monitoring programs.

Temporal trends of Persistent Organic Pollutants (POPs) measured in Arctic air are essential in understanding long-range transport to remote regions and to evaluate the effectiveness of national and international chemical control initiatives, such as the Stockholm Convention (SC) on POPs. Long-term air monitoring of POPs is conducted under the Arctic Monitoring and Assessment Programme (AMAP) at four Arctic stations: Alert, Canada; Stórhöfði, Iceland; Zeppelin, Svalbard; and Pallas, Finland, since the 1990s using high volume air samplers. Temporal trends observed for POPs in Arctic air are summarized in this study. Most POPs listed for control under the SC, e.g. polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs) and chlordanes, are declining slowly in Arctic air, reflecting the reduction of primary emissions during the last two decades and increasing importance of secondary emissions. Slow declining trends also signifies their persistence and slow degradation under the Arctic environment, such that they are still detectable after being banned for decades in many countries. Some POPs, e.g. hexachlorobenzene (HCB) and lighter PCBs, showed increasing trends at specific locations, which may be attributable to warming in the region and continued primary emissions at source. Polybrominated diphenyl ethers (PBDEs) do not decline in air at Canada's Alert station but are declining in European Arctic air, which may be due to influence of local sources at Alert and the much higher historical usage of PBDEs in North America. Arctic air samples are screened for chemicals of emerging concern to provide information regarding their environmental persistence (P) and long-range transport potential (LRTP), which are important criteria for classification as a POP under SC. The AMAP network provides consistent and comparable air monitoring data of POPs for trend development and acts as a bridge between national monitoring programs and SC's Global Monitoring Plan (GMP).

Wastewater treatment plant (WWTP) effluents contain potentially neuroactive chemicals though few methods are available to screen for the presence of such agents. Here, two parallel approaches (in vivo and in vitro) were used to assess WWTP exposure-related changes to neurochemistry. First, fathead minnows (FHM, Pimephales promelas) were caged for four days along a WWTP discharge zone into the Maumee River (Ohio, USA). Grab water samples were collected and extracts obtained for the detection of alkylphenols, bisphenol A (BPA) and steroid hormones. Second, the extracts were then used as a source of in vitro exposure to brain tissues from FHM and four additional species relevant to the Great Lakes ecosystem (rainbow trout (RT), river otter (RO), bald eagle (BE) and human (HU)). The ability of the wastewater (in vivo) or extracts (in vitro) to interact with enzymes (monoamine oxidase (MAO) and glutamine synthetase (GS)) and receptors (dopamine (D2) and N-methyl-d-aspartate receptor (NMDA)) involved in dopamine and glutamate-dependent neurotransmission were examined on brain homogenates. In vivo exposure of FHM led to significant decreases of NMDA receptor binding in females (24–42%), and increases of MAO activity in males (2.8- to 3.2-fold). In vitro, alkylphenol-targeted extracts significantly inhibited D2 (66% in FHM) and NMDA (24–54% in HU and RT) receptor binding, and induced MAO activity in RT, RO, and BE brains. Steroid hormone-targeted extracts inhibited GS activity in all species except FHM. BPA-targeted extracts caused a MAO inhibition in FHM, RT and BE brains. Using both in vivo and in vitro approaches, this study shows that WWTP effluents contain agents that can interact with neurochemicals important in reproduction and other neurological functions. Additional work is needed to better resolve in vitro to in vivo extrapolations (IVIVE) as well as cross-species differences.

The distribution of polycyclic aromatic hydrocarbons (PAHs) in the micro-zones of mangrove sediment is a predominant factors determining PAH bioavailability. In this study, a novel method for the in situ visualization (via microscope) and quantitative investigation of the PAH distribution in the micro-zones of mangrove sediment was established using microscopic fluorescence spectral analysis combined with derivative synchronous fluorescence spectroscopy (MFSA-DSFS). The MFSA-DSFS method significantly suppressed the background fluorescence signal of the sediment (the S/N values increased by over two orders of magnitude). The proportion of the nonpolar organic carbon content in the particulate organic matter (POM) rather than its content in the total organic matter (TOM) showed a significantly positive correlation with the uneven PAH distribution (Relative DC-M values) evaluated using the established method (p < 0.05). The extent of the uneven PAH distribution in the micro-zones of aged sediment was higher than that in the spiked sediment. Moreover, the distribution pattern of the PAHs within the mangrove sediment changed to become more homogeneous in the presence of low-molecular-weight organic acids (LMWOAs), which primarily contribute to increasing the POM content.

A rough estimate of the annual amount of sulfur, arsenic, mercury and fluoride emission from spontaneous combustion of coal gangue in China was determined. The weighted mean concentrations of S, As, Hg, and F in coal gangue are 1.01%, 7.98, 0.18, and 365.54 mg/kg, respectively. Amounts of S, As, Hg, and F emissions from coal gangue spontaneous combustion show approximately 1.13 Mt, and 246, 45, and 63,298 tons in 2013, respectively. The atmospheric release amount of sulfur from coal gangue is more than one tenth of this from coal combustion, and the amounts of As, Hg, and F are close to or even exceed those from coal combustion. China's coal gangue production growth from 1992 to 2013 show an obvious growth since 2002. It may indicate that Chinese coal gangue has become a potential source of air pollution, which should be included in emission inventories.

Plastic pollution is recognised as an emerging threat to aquatic ecosystems, with microplastics now the most abundant type of marine debris. Health effects caused by microplastics have been demonstrated at the species level, but impacts on ecological communities remain unknown. In this study, impacts of microplastics on the health and biological functioning of European flat oysters (Ostrea edulis) and on the structure of associated macrofaunal assemblages were assessed in an outdoor mesocosm experiment using intact sediment cores. Biodegradable and conventional microplastics were added at low (0.8 μg L−1) and high (80 μg L−1) doses in the water column repeatedly for 60 days. Effects on the oysters were minimal, but benthic assemblage structures differed and species richness and the total number of organisms were ∼1.2 and 1.5 times greater in control mesocosms than in those exposed to high doses of microplastics. Notably, abundances of juvenile Littorina sp. (periwinkles) and Idotea balthica (an isopod) were ∼2 and 8 times greater in controls than in mesocosms with the high dose of either type of microplastic. In addition, the biomass of Scrobicularia plana (peppery furrow shell clam) was ∼1.5 times greater in controls than in mesocosms with the high dose of microplastics. This work indicates that repeated exposure to high concentrations of microplastics could alter assemblages in an important marine habitat by reducing the abundance of benthic fauna.

Lead (Pb) has been proved to exert immunotoxicity to influence immune homeostasis in humans. To monitor the internal Pb level and evaluate its effect on natural killer (NK) cells and cytokine/chemokine concentrations, we recruited 285 preschool children from Guiyu, one of the largest electronic waste (e-waste) destinations and recycling areas in the world, and known to have high concentrations of Pb in the air, soil, water, sediment and plants. A total of 126 preschool children were selected from Haojiang as a reference group. Results showed that children in Guiyu, the exposed area, had higher blood Pb levels and lower percentages of NK cells than children from the reference area. A significantly negative association was found between the percentage of NK cells and increasing Pb levels. Moreover, children in Guiyu area had higher platelet counts and IL-1β concentrations, and lower levels of IL-2, IL-27, MIP-1α and MIP-1β were observed in the exposed children. These changes might not be conducive to the development and differentiation of NK cells. Taken together, the elevated Pb levels result in the lower percentages of NK cells, but also alter the levels of platelets, IL-1β and IL-27, which might be unconducive to the activity and function of NK cells.