Concentrations of gaseous elemental mercury (GEM) were continuously monitored from May 2011 to May 2012 at the Wuzhishan State Atmosphere Background Monitoring Station (109°29′30.2″ E, 18°50′11.0″ N) located in Hainan Island. This station is an ideal site for monitoring long-range transport of atmospheric pollutants from mainland China and Southeast Asia to South China Sea. Annual average GEM concentration was 1.58 ± 0.71 ng m⁻³ during the monitoring period, which was close to background values in the Northern Hemisphere. GEM concentrations showed a clear seasonal variation with relatively higher levels in autumn (1.86 ± 0.55 ng m⁻³) and winter (1.80 ± 0.62 ng m⁻³) and lower levels in spring (1.16 ± 0.45 ng m⁻³) and summer (1.43 ± 0.46 ng m⁻³). Long-range atmospheric transport dominated by monsoons was a dominant factor influencing the seasonal variations of GEM. The GEM diel trends were related to the wind speed and long-range atmospheric mercury transport. We observed 30 pollution episodes throughout the monitoring period. The analysis of wind direction and backward trajectory suggested that elevated GEM concentrations at the monitoring site were primarily related to the outflows of atmospheric Hg from mainland China and the Indochina peninsula. The △GEM/△CO values also suggested that GEM was significantly affected by the long-range transport from the anthropogenic sources and biomass burning in Asia and Indochina peninsula.

We monitored cryptic herpetofauna at Savannas Preserve State Park, Florida, by combining artificial cover counts with a quantitative paradigm for constructing and calculating population indices. Weekly indices were calculated from two consecutive days of data collection each week for 7 months from mid-winter to mid-summer in three habitats. Seventeen species were observed at least once, and time trends using index values were followed for six species. Among these, abundance and seasonal pattern information were obtained for an exotic species (greenhouse frog) and a species identified by the Florida Committee on Rare and Endangered Plants and Animals as threatened (Florida scrub lizard). We identified winter as the optimal time in this area to monitor populations for conducting annual assessments. This combined observation and indexing approach could provide managers or researchers with an economical means to quantitatively index population trends for multiple cryptic herpetofauna species simultaneously. Using artificial cover to sample within a population indexing design can be generalized beyond monitoring herpetofauna. Other forms of artificial cover that can be used as observation stations include aquatic artificial substrates, artificial tree cavities, artificial reefs, and other artificial aquatic structures and artificial sea grass units, among many others, and a wide range of taxa are suitable for population monitoring using artificial cover as observation stations in the approach we present, including insects, soil invertebrates, micro and macro aquatic invertebrates, fish, crustaceans, and small mammals.

Bohai Sea is one of the most intensively exploited region in the world and its environment has been severely impacted by the extensive human activities. The Yellow River is the most important river which connects with the Bohai Sea. Therefore, this study focused on analyzing heavy metals (HMs) in 21 surface sediment samples collected from the Yellow River, China. Sequential extraction procedure (SEP), proposed by the Community Bureau of Reference (BCR), was applied in the present study to determine the concentration and fractionation characteristics of these HMs. The aim of this study was to investigate the spatial distribution, fractionation, risk assessment, and sources of HMs, including copper (Cu), zinc (Zn), lead (Pb), chromium (Cr), iron (Fe), manganese (Mn), and nickel (Ni). The results obtained from this research will play a significant role in understanding the migration, transformation, and accumulation of HMs for future research in study area. Results of fractionation revealed that most of the HMs in the study area mainly existed in residual fraction; however, Mn mostly existed in exchangeable fraction. A high percentage of reducible fractions was found for Cu and Pb. The mean contamination factor (Cf) values indicated that Pb was the highest. It was >1 and showed moderate contamination, followed by Cr, Cu, Mn, Ni, and Zn, had <1 and indicated low contamination. Among studied HMs Pb had higher enrichment factor (EF) as compared to others. Significant positive correlations within all studied HMs and principal component analysis (PCA) results indicated their common sources, however, Pb showed the different contamination sources. The total contents of HMs in sediment were compared with the threshold effect level (TEL) and probable effect level (PEL) sediment quality guideline (TEL/PEL-based SQGs) values for trace metals in sediment, as well as literature reported data for comparative purposes, which indicated that the selected river in present study is not severe.

Mixing can influence the optical, physical, and chemical characteristics of aerosols, which in turn can modify their life cycle and radiative effects. Assumptions on the mixing state can lead to uncertain estimates of aerosol radiative effects. To examine the effect of mixing on the aerosol characteristics, and their influence on radiative effects, aerosol mixing states are determined over four environmentally distinct locations (Karachi, Gwangju, Osaka, and Singapore) in Asia, an aerosol hot spot region, using measured spectral aerosol optical properties and optical properties model. Aerosol optical depth (AOD), single scattering albedo (SSA), and asymmetry parameter (g) exhibit spectral, spatial, and temporal variations. Aerosol mixing states exhibit large spatial and temporal variations consistent with aerosol characteristics and aerosol type over each location. External mixing of aerosol species is unable to reproduce measured SSA over Asia, thus providing a strong evidence that aerosols exist in mixed state. Mineral dust (MD) (core)-Black carbon (BC) (shell) is one of the most preferred aerosol mixing states. Over locations influenced by biomass burning aerosols, BC (core)-water soluble (WS, shell) is a preferred mixing state, while dust gets coated by anthropogenic aerosols (BC, WS) over urban regions influenced by dust. MD (core)-sea salt (shell) mixing is found over Gwangju corroborating the observations. Aerosol radiative forcing exhibits large seasonal and spatial variations consistent with features seen in aerosol optical properties and mixing states. TOA forcing is less negative/positive for external mixing scenario because of lower SSA. Aerosol radiative forcing in Karachi is a factor of 2 higher when compared to Gwangju, Osaka, and Singapore. The influence of g on aerosol radiative forcing is insignificant. Results emphasize that rather than prescribing one single aerosol mixing state in global climate models regionally and temporally varying aerosol mixing states should be included for more accurate assessment of aerosol radiative effects

Soil contamination by heavy metals in coal mine wastelands is a significant environmental issue in most developing countries. The purpose of this study is to evaluate contamination characteristics in the coal mine wastelands of Sanlidong coal mine, Tongchuan, China. To achieve this goal, we conducted field sampling work, followed by further analysis of the properties of soil contamination and accumulation characteristics in woody plants. At this site, the pH value ranged from 4.41 to 7.88, and the nutrient content of the soil rose gradually with the time after deposition due to the weathering effect improving the soil quality. Meanwhile, the levels of Cd, Cr, Cu, Ni, and Zn gradually decreased with the passage time. Generally, heavy metal contamination was found to be more serious in the discharge refuse area, with Cd contamination at moderate or heavy levels; Ni, Zn, and Cu contamination at light levels; and with no Cr contamination. The geoaccumulation index (I gₑₒ) was highest for Cd (2.38–3.14), followed by Ni, Zn, Cu, and Cr. Heavy metals accumulated on the lower slopes and spread to the surrounding areas via hydrodynamic effects and wind. According to transfer and enrichment coefficient analyses, Robinia pseudoacacia, Ulmus pumila, and Hippophae rhamnoides with considerable biomass could be used as pollution-resistant tree species for vegetation restoration. This study provided a theoretical basis for the restoration of the ecological environment in the mining area. This report described a link between heavy metal contamination of soils and growth dynamics of woody plants in China.

Perfluorooctanoic acid (PFOA) is extremely persistent and bioaccumulative in the environment; thus, it is very urgent to investigate an effective and moderate technology to treat the pollution of PFOA. In this study, a process combined iron and granular activated carbon (Fe⁰/GAC) micro-electrolysis with VUV-Fenton system is employed for the remediation of PFOA. Approximately 50 % PFOA (10 mg L⁻¹) could be efficiently defluorinated under the following conditions: pH 3.0, dosage of Fe 7.5 g L⁻¹, dosage of GAC 12.5 g L⁻¹, and concentration of H₂O₂ 22.8 mmol L⁻¹. Meanwhile, during the process, evident defluorination was observed and the concentration of fluoride ion was eventually 3.23 mg L⁻¹. The intermediates including five shorter-chain perfluorinated carboxylic acids (PFCAs), i.e., C7, C6, C5, C4, and C3, were also analyzed by high-performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS) and defluorination mechanisms of PFOA was proposed, which involved photochemical of OH·, direct photolysis (185-nm VUV), and photocatalytic degradation of PFOA in the presence of Fe³⁺ (254-nm UV).

Landfills represent a severe environmental problem mainly due to the generation of leachates, and this study aimed to evaluate sublethal effects of a domestic landfill leachate in the freshwater bivalve Corbicula fluminea. Clams were submitted to in situ tests along a stream, at three sites, representing increasing distances from the leachate discharge (Pq1, Pq2, and Pq3), for 1, 5, and 15 days. The following biomarkers were analyzed in the gills and digestive glands: 7-ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST) activities, multixenobiotic resistance mechanism (MXR), total antioxidant capacity (TAC), reactive oxygen species (ROS), and lipid peroxidation (LPO). Metallothionein (MT) content was determined in the gills and DNA damage in hemocytes. The mortality rate of animals during in situ tests was reduced as the distance from the leachate discharge source increased. On the other hand, biomarker results showed sublethal effects on C. fluminea confined at all sites of PqS. GST, TAC, ROS, and DNA damage were the most significant biomarkers for this species and should be considered for future monitoring and assessment of freshwater environments located in landfill areas.

Glomalin is a specific fungal glycoprotein produced by arbuscular mycorrhizal (AM) fungi belonging to the Glomerales which could efficiently sequestrate heavy metals. The glomalin has been introduced as a heat shock protein and there are evidences that increasing levels of heavy metals could enhance its production. We examined the influence of Cd concentrations on glomalin production by AM fungus, as well as its contribution to the sequestration of Cd in both pot and in vitro culture conditions. Pot experiment was carried out using pure sand with Trifolium repens L. as host plant, mycorrhized by Rhizophagus irregularis and treated with Cd levels of 0, 15, 30, and 45 μM. In vitro experiment was performed in two-compartment plates containing the transformed carrot roots mycorrhized with the same fungus and treated with Cd levels of 0, 0.001, 0.01, and 0.1 mM. The immunoreactive and Bradford reactive glomalin contents in both experiments increased as so raising Cd concentration. Total Cd sequestrated by hyphal glomalin in both cultures was significantly increased as the levels of Cd increased. The highest contents of Cd sequestration in pot (75.78 μg Cd/mg glomalin) and in vitro (11.44 μg Cd/mg glomalin) cultures were recorded at the uppermost levels of Cd, which significantly differed with other levels. Our results suggested that under Cd-induced stress, stimulated production of glomalin by AM fungus may be a protective mechanism against the toxic effect of Cd.

The present study on organophosphate deals with the reports on pollution and toxicity cases throughout India. The use of pesticides was introduced in India during the 1960s which are now being used on a large scale and represents the common feature of Indian agriculture. Use of organophosphates as a pesticide came as an alternative to chlorinated hydrocarbons due to their easy degradability. Although these xenobiotics degrade under natural condition, their residues have been detected in soil, sediments, and water due to their non-regulated usage practice. The over-reliance on pesticides has not only threatened our environment but contaminations of organophosphate residues have been also detected in certain agricultural products like tea, sugars, vegetables, and fruits throughout India. This paper highlights many of the cases where different organophosphates have been detected exceeding their respective MRL values. Some organophosphates detected are so hazardous that even WHO has listed them in class 1a and class 1b hazardous group. Presence of their residues in blood, milk, honey, and tissues of human and animals revealed their excessive use and bioaccumulating capabilities. Their intentional or unintentional uptake is causing thousands of deaths and severity each year. Most of the toxicity cases presented here are due to their uptake during a suicidal attempt. This shows how easily these harmful substances are available in the market.

Analytical methods using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of metabolites or contaminants (or both) in various tissues of aquatic organisms and in the aquatic environment have received increasing attention in the last few years. This review discusses the findings relevant to such procedures published between 2005 and 2015. The aim is to evaluate the advantages, restrictions, and performances of the procedures from sample preparation to mass spectrometry measurement. To support these discussions, a general knowledge on LC-MS/MS is also provided.