Increases in water temperature, as a result of climate change, may influence biogeochemical cycles, sediment-water fluxes and consequently environmental sustainability. Effects of rising temperature on dynamics of nitrate, nitrite, ammonium, dissolved inorganic nitrogen (DIN), dissolved reactive phosphorus (DRP), dissolved organic carbon (DOC) and gaseous nitrogen (N2 and N2O) were examined in a subtropical river (the Jiulong River, southeast China) by microcosm experiments. Slurry sediments and overlying water were collected from three continuous cascade reservoirs, and laboratory incubations were performed at four temperature gradients (5 °C, 15 °C, 25 °C and 35 °C). Results indicated: (1) warming considerably increased sediment ammonium, DIN and DOC fluxes to overlying water; (2) warming increased retention of nitrate, and to a lesser extent, nitrite, corresponding to increases in N2 and N2O emission; (3) DRP was retained but released from Fe/Al-P enriched sediments at high temperature (35 °C) due to enhanced coupled transformation of carbon and nitrogen with oxygen deficiency. Using relationships between sediment fluxes and temperature, a projected 2.3°C-warming in future would increase ammonium flux from sediment by 7.0%–16.8%, while increasing nitrate flux into sediment by 8.9%–28.6%. Moreover, substrates (e.g., grain size, carbon availability) influenced nutrient delivery and cycling across cascade reservoirs. This study highlights that warming would increase bioreactive nutrient (i.e., ammonium and phosphate) mobilization with limited gaseous N removal from sediments, consequently deteriorating water quality and increasing eutrophication with future climate change.

Polycyclic aromatic hydrocarbons (PAHs), nicotine, cotinine, and metals in human hair have been used as important environmental exposure markers. We aimed to develop a simple method to simultaneously analyze these pollutants using a small quantity of hair. The digestion performances of tetramethylammonium hydroxide (TMAH) and sodium hydroxide (NaOH) for human hair were compared. Various solvents or their mixtures including n-hexane (HEX), dichloromethane (DCM) and trichloromethane (TCM), HEX:DCM32 (3/2) and HEX:TCM73 (7/3) were adopted to extract organics. The recoveries of metals were determined under an optimal operation of digestion and extraction. Our results showed that TMAH performed well in dissolving human hair and even better than NaOH. Overall, the recoveries for five solutions were acceptable for PAHs, nicotine in the range of 80%–110%. Except for HEX, other four extraction solutions had acceptable extraction efficiency for cotinine from HEX:TCM73 (88 ± 4.1%) to HEX:DCM32 (100 ± 2.8%). HEX:DCM32 was chosen as the optimal solvent in consideration of its extraction efficiency and lower density than water. The recoveries of 12 typical major or trace metals were mainly in the range of 90%–110% and some of them were close to 100%. In conclusion, the simultaneous analysis of PAHs, nicotine, cotinine, and metals was feasible. Our study provided a simple and low-cost technique for environmental epidemiological studies.

Severe trace metal pollution due to industrial effluents releases was found in Jiulong River Estuary, Southern China. In this study, water samples were collected during effluent release events to study the dynamic changes of environmental conditions and metal partitioning among dissolved, particulate and colloidal phases controlled by estuarine mixing. Intermittent effluent discharges during low tide caused decreasing pH and dissolved oxygen, and induced numerous suspended particulate materials and dissolved organic carbon to the estuary. Different behaviors of Cu, Zn, Ni, Cr and Pb in the dissolved fraction against the conservative index salinity indicated different sources, e.g., dissolved Ni from the intermittent effluent. Although total metal concentrations increased markedly following effluent discharges, Cu, Zn, Cr, Pb were predominated by the particulate fraction. Enhanced adsorption onto particulates in the mixing process resulted in elevated partitioning coefficient (Kd) values for Cu and Zn, and the particle concentration effect was not obvious under such anthropogenic impacts. Colloidal proportion of these metals (especially Cu and Zn) showed positive correlations with dissolved or colloidal organic carbon, suggesting the metal-organic complexation. However, the calculated colloidal partitioning coefficients were relatively constant, indicating the excess binding capacity. Overall, the intermittent effluent discharge altered the particulate/dissolved and colloidal/soluble phase partitioning process and may further influence the bioavailability and potential toxicity to aquatic organisms.

The presence of pharmaceuticals in the environment has triggered concern among the general population and received considerable attention from the scientific community in recent years. However, only a few publications have focused on anticancer drugs, a class of pharmaceuticals that can exhibit cytotoxic, genotoxic, mutagenic, carcinogenic and teratogenic effects. The present study investigated the photodegradation, biodegradation, bacterial toxicity, mutagenicity and genotoxicity of cyclophosphamide (CP) and 5-fluorouracil (5-FU). The photodegradation experiments were performed at a neutral to slight pH range (7–7.8) using two different lamps (medium-pressure mercury lamp and a xenon lamp). The primary elimination of the parent compounds was monitored by means of liquid chromatography tandem mass spectrometry (LC-IT-MS/MS). NPOC (non-purgeable organic carbon) analyses were carried out in order to assess mineralization rates. The Closed Bottle Test (CBT) was used to assess ready biodegradability. A new method using Vibrio fischeri was adopted to evaluate toxicity. CP was not degraded by any lamp, whereas 5-FU was completely eliminated by irradiation with the mercury lamp but only partially by the Xe lamp. No mineralization was observed for the experiments performed with the Xe lamp, and a NPOC removal of only 18% was registered for 5-FU after 256 min using the UV lamp. Not one of the parent compounds was readily biodegradable in the CBT. Photo transformation products (PTPs) resulting from photolysis were neither better biodegradable nor less toxic than the parent compound 5-FU. In contrast, the results of the tests carried out with the UV lamp indicated that more biodegradable and non-toxic PTPs of 5-FU were generated. Three PTPs were formed during the photodegradation experiments and were identified. The results of the in silico QSAR predictions showed positive mutagenic and genotoxic alerts for 5-FU, whereas only one of the formed PTPs presented positive alerts for the genotoxicity endpoint.

Road traffic noise exposure has been associated with auditory and non-auditory health effects, but few studies report noise characteristics. This study determines 24-h noise levels and analyzes their frequency components to investigate associations between seasons, meteorology, land-use types, and traffic. We set up 50 monitoring stations covering ten different land-use types and conducted measurements at three times of the year to obtain 24-h-average A-weighted equivalent noise levels (LAeq,24h) and frequency analyses from 2013 to 2014 in Taichung, Taiwan. Information on land-use types, road parameters, traffic flow rates, and meteorological variables was also collected for analysis with the annual averages of road traffic noise and its frequency components. The annual average LAeq,24h in Taichung was 66.4 ± 4.7 A-weighed decibels (dBA). Significant differences in LAeq,24h and frequency components were observed between land-use types (all p-values < 0.001), but not between seasons, with the highest two noise levels of 71.2 ± 1.0 dBA and 70.0 ± 2.6 dBA measured in stream-channel and commercial areas, with the highest component being 61.4 ± 5.3 dBA at 1000 Hz. Road width, traffic flow rates, and land-use types were significantly associated with annual average LAeq,24h (all p-values < 0.050). Noise levels at 125 Hz had the highest correlation with total traffic (Spearman's coefficient = 0.795) and the highest prediction in the multiple linear regression (R2 = 0.803; adjusted R2 = 0.765). These findings reveal the spatial variation in road traffic noise exposure in Taichung. The highest correlation and predictive capacity was observed between this variation and noise levels at 125 Hz. We recommend that governmental agencies should take actions to reduce noise levels from traffic vehicles.

Chemical and toxicological characterization of the water-soluble fraction of size-segregated urban particulate matter (PM) (<0.49, 0.49–0.97, 0.97–1.5, 1.5–3.0, 3.0–7.2 and >7.2 μm) was carried out at two urban sites, traffic and urban background, during the cold and the warm period. Chemical analysis of the water-soluble PM fraction included ionic species (NO3−, SO42−, Cl⁻, Na⁺, NH4⁺, K⁺, Mg²⁺, Ca²⁺), water-soluble organic carbon (WSOC), and trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Zn, Pt, Pd, Rh, Ru, Ir, Ca, and Mg). The dithiothreitol (DTT) assay was employed for the abiotic assessment of the oxidative PM activity. Cytotoxic responses were investigated in vitro by applying the mitochondrial dehydrogenase (MTT) and the lactate dehydrogenase (LDH) bioassays on human lung cells (MRC-5), while DNA damage was estimated by the single cell gel electrophoresis assay, known as Comet assay. The correlations between the observed bioactivity responses and the concentrations of water-soluble chemical PM constituents in the various size ranges were investigated. The results of the current study corroborate that short-term bioassays using lung human cells and abiotic assays, such as the DTT assay, could be relevant to complete the routine chemical analysis and to obtain a preliminary screening of the potential effects of PM-associated airborne pollutants on human health.

Fungicides in aquatic environments can impact non-target bacterial and fungal communities and the invertebrate detritivores responsible for the decomposition of allochthonous organic matter. Additionally, in some aquatic systems daily water temperature fluctuations may influence these processes and alter contaminant toxicity, but such temperature fluctuations are rarely examined in conjunction with contaminants. In this study, the shredding amphipod Hyalella azteca was exposed to the fungicide pyraclostrobin in three experiments. Endpoints included mortality, organism growth, and leaf processing. One experiment was conducted at a constant temperature (23 °C), a fluctuating temperature regime (18–25 °C) based on field-collected data from the S. Llano River, Texas, or an adjusted fluctuating temperature regime (20–26 °C) based on possible climate change predictions. Pyraclostrobin significantly reduced leaf shredding and increased H. azteca mortality at concentrations of 40 μg/L or greater at a constant 23 °C and decreased leaf shredding at concentrations of 15 μg/L or greater in the fluctuating temperatures. There was a significant interaction between temperature treatment and pyraclostrobin concentration on H. azteca mortality, body length, and dry mass under direct aqueous exposure conditions. In an indirect exposure scenario in which only leaf material was exposed to pyraclostrobin, H. azteca did not preferentially feed on or avoid treated leaf disks compared to controls. This study describes the influence of realistic temperature variation on fungicide toxicity to shredding invertebrates, which is important for understanding how future alterations in daily temperature regimes due to climate change may influence the assessment of ecological risk of contaminants in aquatic ecosystems.

To investigate the characteristics and contributions of the sources of fine particulate matter with a size of up to 2.5 μm (PM2.5) during the period when pollution events could easily occur in Taoyuan aerotropolis, Taiwan, this study conducted sampling at three-day intervals from September 2014 to January 2015. Based on the mass concentration of PM2.5, the sampling days were classified into high PM2.5 concentration event days (PM2.5>35 μg m−3) and non-event days (PM2.5<35 μg m−3). In addition, the chemical species, including water-soluble inorganic ions, carbonaceous components, and metal elements, were analyzed. The sources of pollution and their contributions were estimated using the positive matrix factorization (PMF) model. Furthermore, the effect of the weather type on the measurement results was also explored based on wind field conditions. The mass fractions of Cl− and NO3− increased when a high PM2.5 concentration event occurred, and they were also higher under local emitted conditions than under long range transported conditions, indicating that secondary nitrate aerosols were the major increasing local species that caused high PM2.5 concentration events. Seven sources of pollution could be distinguished using the PMF model on the basis of the characteristics of the species. Industrial emissions, coal combustion/urban waste incineration, and local emissions from diesel/gasoline vehicles were the main sources that contributed to pollution on high PM2.5 concentration event days. In order to reduction of high PM2.5 concentration events, the control of diesel and gasoline vehicle emission is important and should be given priority.

Understanding how engineered nanoparticles (ENPs) interact with natural organic acids is important to ecological risk assessment of ENPs, but this interaction remains poorly studied. Here, we investigate the dispersion stability, ion release, and toxicity of yttrium oxide nanoparticles (nY2O3) suspensions after exposure to two low molecular weight natural organic acids (LOAs), namely benzoic acid and gallic acid. We find that in the presence of LOAs the nY2O3 suspensions become more stable with surface zeta potential more positive or negative, accompanied by small agglomerated size. LOA interaction with nY2O3 is shown to promote the release of dissolved yttrium from the nanoparticles, depending on the concentrations of LOAs. Toxic effects of the nY2O3 suspensions incubated with LOAs on Scenedesmus obliquus as a function of their mixture levels show three types of signs: stimulation, inhibition, and alleviation. The mechanism of the effects of LOAs on the nY2O3 toxicity may be mainly associated with the degree of agglomeration, particle-induced oxidative stress, and dissolved yttrium. Our results stressed the importance of LOA impacts on the fate and toxicity of ENPs in the aquatic environment.

Antibiotic resistance genes (ARGs) are present in surface water and often cannot be completely eliminated by drinking water treatment plants (DWTPs). Improper elimination of the ARG-harboring microorganisms contaminates the water supply and would lead to animal and human disease. Therefore, it is of utmost importance to determine the most effective ways by which DWTPs can eliminate ARGs. Here, we tested water samples from two DWTPs and distribution systems and detected the presence of 285 ARGs, 8 transposases, and intI-1 by utilizing high-throughput qPCR. The prevalence of ARGs differed in the two DWTPs, one of which employed conventional water treatments while the other had advanced treatment processes. The relative abundance of ARGs increased significantly after the treatment with biological activated carbon (BAC), raising the number of detected ARGs from 76 to 150. Furthermore, the final chlorination step enhanced the relative abundance of ARGs in the finished water generated from both DWTPs. The total enrichment of ARGs varied from 6.4-to 109.2-fold in tap water compared to finished water, among which beta-lactam resistance genes displayed the highest enrichment. Six transposase genes were detected in tap water samples, with the transposase gene TnpA-04 showing the greatest enrichment (up to 124.9-fold). We observed significant positive correlations between ARGs and mobile genetic elements (MGEs) during the distribution systems, indicating that transposases and intI-1 may contribute to antibiotic resistance in drinking water. To our knowledge, this is the first study to investigate the diversity and abundance of ARGs in drinking water treatment systems utilizing high-throughput qPCR techniques in China.