The concentrations of major heavy metals in organs of two cyprinid fish and in water collected from three sections of the Kor River, Iran, were determined using the induction coupled plasma method. The concentrations of heavy metals in tissue of fish from the middle sampling zone were significantly higher (p < 0.05) than those from the other two sampling zones, whereas no significant differences (p > 0.05) were detected between the two sexes and species. Estradiol in females and progesterone and testosterone in males from the middle study site were significantly (p < 0.05) lower than values from the other two sites. Pathological changes in blood cells, liver, and kidneys of fishes were significantly higher in highly polluted areas (middle sampling zone). So heavy metals exposure can effectively decreases estrogenic and androgenic secretion in fish. These results show that industrial activities have polluted the river and that heavy metals exposure can induce pathological changes in fish organs.

The levels of fluctuating asymmetry [random differences between symmetric organismal traits, fluctuating asymmetry (FA)] in the fourth instar of Chironomus spp. larvae inhabiting an agrochemical polluted river [Permatang Rawa River (PRR)] in the Juru River Basin, northeastern peninsular Malaysia, were measured. The PRR receives waters primarily from adjacent rice fields which are exposed to fertilizer and pesticide residues. Samples of larvae, water, and sediments were collected monthly from November 2007 to June 2008. In situ measurements of water pH and dissolved oxygen were made at three sampling locations along the river. Monthly water and benthic sediment collections were also conducted for the following laboratory water analyses: biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and ammonium-N content. Non-residual metals in the sediment samples were also analyzed. The water quality index (WQI) of the PRR was also calculated. This study attempted to relate FA levels based on selected traits of Chironomus spp. larval head capsule (mentum width and first and second antennal segment length) to water quality and sediment heavy metal contamination in the PRR. All monthly measurements of FA levels including transcriptors (FA10a, FA4a, ME3, and ME1) and indices [FA, absolute asymmetry (AbsFA), and composite fluctuating asymmetry (CFA)] were calculated. The ordination model of redundancy analysis showed that the dissolved oxygen and water quality in the river expressed as WQI were negatively correlated with all FA indices (FA, AbsFA, and CFA) of the larval mentum width and length of antennal segments I and II. The water pH, BOD, and COD and sediment Cu positively influenced the FA incidence in the larval mentum. The FA indices of the antennal segment I were positively correlated with the increase in the levels of water pH, ammonium-N, BOD, and COD. The FA indices, especially CFA, were sensitive to the water pH and ammonium-N and sediment contaminated by Mn, Cu, and Zn. The FA levels calculated as FA indices of the larval antennal segment II length were positively correlated with water TSS and sediment Mn, Cu, Zn, and Ni. This study revealed that the river water quality and heavy metal contamination affect developmental stability in Chironomus spp. larvae. The FA indices of different structures in the Chironomus spp. larval head capsule could be used as bioindicators for water and sediment pollution.

The objective of this study was to develop an index of biological integrity (IBI) for national-level monitoring of watersheds as an ecosystem health assessment methodology for the South Korean government. A 10-metric IBI model (IBIKW) was developed for watershed management and then applied to 76 streams in four major watersheds in Korea. The model assessments showed that 32.9% of all streams were judged to be in ‘excellent–good’ condition, whereas 67.1% were in ‘fair–poor’ condition, indicating severely impaired ecological health. Nutrient analyses of stream water revealed a two- to fivefold increase in nutrient and biological oxygen demand (BOD) levels in urban- and cropland-dominant streams compared to forest-dominant streams. The guild structure within the watersheds indicated that tolerant species were predominant in severely degraded regions (BOD > 6 mg L−1), and sensitive species were distributed in regions with BOD < 2 mg L−1. Factors affecting ecosystem health (IBIKW scores) included chemical water quality parameters, physical habitat parameters and land use around the stream. In particular, land use was one of the major factors influencing ecosystem health, as indicated by the strong relationships between the percentages of urban and forest streams and the IBIKW scores. The integrated ecosystem health assessment technique developed here can be applied for both regular bioassessments and post-restoration assessments.

The concentrations of Hg, Cu, Pb, Cd, and Zn accumulated by regional macrophytes were investigated in three tropical wetlands in Colombia. The studied wetlands presented different degrees of metal contamination. Cu and Zn presented the highest concentrations in sediment. Metal accumulation by plants differed among species, sites, and tissues. Metals accumulated in macrophytes were mostly accumulated in root tissues, suggesting an exclusion strategy for metal tolerance. An exception was Hg, which was accumulated mainly in leaves. The ranges of mean metal concentrations were 0.035–0.953 mg g−1 Hg, 6.5–250.3 mg g−1 Cu, 0.059–0.245 mg g−1 Pb, 0.004–0.066 mg g−1 Cd, and 31.8−363.1 mg g−1 Zn in roots and 0.033–0.888 mg g−1 Hg, 2.2–70.7 mg g−1 Cu, 0.005–0.086 mg g−1 Pb, 0.001–0.03 mg g−1 Cd, and 12.6–140.4 mg g−1 Zn in leaves. The scarce correlations registered between metal concentration in sediment and plant tissues indicate that metal concentrations in plants depend on several factors rather than on sediment concentration only. However, when Cu and Zn sediment concentrations increased, these metal concentrations in tissues also increased in Eichhornia crassipes, Ludwigia helminthorriza, and Polygonum punctatum. These species could be proposed as Cu and Zn phytoremediators. Even though macrophytes are important metal accumulators in wetlands, sediment is the main metal compartment due to the fact that its total mass is greater than the corresponding plant biomass in a given area.

Fluid catalytic cracking of heavy ends to high-value liquid fuels is a common unit operation in oil refineries. In this process, the heavy feedstock that contains sulfur is cracked to light products. Sulphur content is hence redistributed in the liquid and gaseous products and coke of the catalyst used in this process. The coke is later burnt in the regenerator releasing sulfur into the discharged flue gas as SO₂. In the present work, comprehensive emission inventories for a fluid catalytic cracking unit in a typical oil refinery are prepared. These inventories are based on calculations that assume complete combustion of catalyst coke in the regenerator. Yearly, material balances for both SO₂ and particulate matters emissions are carried out taking into account seasonal variations in the operation of the process unit. The results presented in this article reflect the variation of sulfur in feedstock originating from various units in the refinery. The refinery operations are not dependant on seasons but controlled by market-driven conditions to maximize the profit. The seasonal impact on refinery emissions is minimal due to its operation at optimum capacity fulfilling the international market demand. The data presented and analyzed here can be used to assess the hazardous impact of SO₂ and particulate matter emissions on surrounding areas of the refinery.

Osmium tetroxide (OsO4) is one of the most toxic air contaminants but its environmental effects are poorly understood. Here, for the first time, we present evidence of osmium uptake in a common herbivore (bank vole, Myodes glareolus) in boreal forests of northern Sweden. Voles (n = 22) and fruticose arboreal pendular lichens, the potential main winter food source of the vole, were collected along a spatial gradient to the west of a steelwork in Tornio, Finland at the Finnish–Swedish border. 187Os/188Os isotope ratios increased and osmium concentrations decreased in lichens and voles along the gradient. Osmium concentrations in lichens were 10,000-fold higher than those in voles. Closest to the steelwork, concentrations were highest in kidneys rather than skin/fur that are directly exposed to airborne OsO4. The kidney-to-body weight ratio was higher at the two localities close to the steelwork. Even though based on a small sample size, our results for the first time demonstrate that osmium is taken up, partitioned, and accumulated in mammal tissue, and indicate that high kidney-to-body weight ratios might be induced by anthropogenic osmium.

Typical controlled drainage structures in drainage ditches provide drainage management strategies for isolated temporal periods. Innovative, low-grade weirs are anticipated to provide hydraulic control on an annual basis, as well as be installed at multiple sites within the drainage ditch for improved spatial biogeochemical transformations. This study provides evidence toward the capacity of low-grade weirs for nutrient reductions, when compared to the typical controlled drainage structure of a slotted riser treatment. Three ditches with weirs were compared against three ditches with slotted risers, and two control ditches for hydraulic residence time (HRT) and nutrient reductions. There were no differences in water volume or HRT between weired and riser systems. Nutrient concentrations significantly decreased from inflow to outflow in both controlled drainage strategies, but there were few statistical differences in N and P concentration reductions between controlled drainage treatments. Similarly, there were significant declines in N and P loads, but no statistical differences in median N and P outflow loads between weir (W) and riser (R) ditches for dissolved inorganic phosphate (W, 92%; R, 94%), total inorganic phosphate (W, 86%; R, 88%), nitrate-N (W, 98%; R, 96%), and ammonium (W, 67%; R, 85%) when nutrients were introduced as runoff events. These results indicate the importance of HRT in improving nutrient reductions. Low-grade weirs should operate as important drainage control structures in reducing nutrient loads to downstream receiving systems if the hydraulic residence time of the system is significantly increased with multiple weirs, as a result of ditch length and slope.

This study examined a comparative degradation of various chlorinated phenolic compounds including phenol, 4-chlorophenol (4-CP), 2,6-dichlorophenol (2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and pentachlorophenol (PCP) using 28, 580, and 1,000 kHz ultrasonic reactors. The concentration of hydrogen peroxide was also determined in order to investigate the efficacy of different sonochemical reactors for hydroxyl radical production. Clearly, it was observed that the 580 kHz sonochemical reactor had maximum efficacy for hydroxyl radical production. The degradation of all the compounds followed the order; 580 kHz (91–93%) > 1,000 kHz (84–86%) > 28 kHz (17–34%) with an initial concentration of 2.5 mg L−1 at a reaction time of 40 min with ultrasonic power of 200 ± 3 W and aqueous temperature of 20 ± 1°C in each experiment. Overall, the degradation of those phenolic compounds followed the order, PCP > 2,3,4,6-TeCP > 2,4,6-TCP > 2,6-DCP > 4-CP > phenol at various frequencies in the presence/absence of a radical scavenger (tert-butyl alcohol). It was revealed that the correlations between the compound degradation rates and the physicochemical parameters, R 2 = 0.99 for octanol–water partition coefficient, R 2 = 0.95 for water solubility, R 2 = 0.94 for vapor pressure, and R 2 = 0.88 for Henry’s law constant, excluding PCP, were very good in the entire range of each parameter.

Methane fluxes in alpine ecosystems remain insufficiently studied, especially in terms of the magnitude, temporal, and spatial patterns. To quantify the mean methane emission of alpine ecosystems, methane fluxes were measured among six ecosystems and microsites within each ecosystem at Zoige National Wetland Reserve. The average methane emission from Zoige Plateau was 2.25 mg CH4 m−2 h−1, which fell into the range of methane emission rate reported by a number of studies in other alpine wetlands. Prevailing ecosystem types had important impacts on the methane flux on the landscape scale. In the wet ecosystems, the microsites had different methane emissions resulting from the differences in the depth of water table and associated vegetation characteristics. The identification of the microsites based on their vegetation characteristics thus allows upscaling of methane emissions in these ecosystems. However, in the dry ecosystems showing even methane uptake, the spatial variation in the methane fluxes was low and the vegetation has a poor predicative value for the methane fluxes. There, the soil porosity linked to the gas diffusion rate in soil would be the key factor explaining methane fluxes.

Different substrates were evaluated to investigate their effect on nitrate removal and denitrifying bacterial community in soils obtained from wetland. Serial batch kinetic tests were conducted on soils obtained from wetland mixed with glucose and sawdust using KNO3 solution. Column tests were also conducted on soils obtained from wetland mixed with three different substrates (glucose, sawdust, and scoria coated with zero-valent iron) using KNO3 solution. For the batch tests, the nitrate removal efficiency for soil mixed with glucose was comparable to that for soil mixed with sawdust, but the nitrate removal rate for soil mixed with glucose (23.3 NO3 −-N mg/L-d) was approximately eight times higher than that for soil mixed with sawdust (2.8 NO3 −-N mg/L-d). For column tests among soil samples, nitrate removal efficiency was highest in soil mixed with glucose, which is an easily biodegradable carbon source. Removal efficiency increased with increasing incubation time for both soil samples with glucose and sawdust. A phylogenetic analysis based on nitrate reductase gene demonstrated that the different carbon sources affected both the diversity and compositions of the denitrifying bacterial in soil samples.