Characteritization of, and health risks from, polychlorinated dibenzo-p-dioxins/dibenzofurans from incense burned in a temple

Polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) may cause adverse health effects. However, PCDD/F emissions from burning incense in temples have rarely been addressed. This study investigates PCDD/F emissions from burning incense in a temple. The mean total PCDD/F concentrations were 72.4-82.2 pg Nm^− 3 at two indoor sites; their corresponding mean total PCDD/Fs I-TEQ concentrations (0.24-0.27 pg I-TEQ Nm^− 3) were ~ 11 times that at a background location. In air samples collected from burning incense, OCDFs accounted for approximately 90% of total PCDD/Fs at the two indoor sites and an outdoor site near the temple, while the major PCDD/Fs in incense ash were PCDDs. The total PCDD/F content and toxic equivalent value of incense ash were 617 pg g^− 1 and 1.55 pg I-TEQ g^− 1, respectively. At the three sites inside/outside the temple, the air and ash samples contained the same four primary PCDD/Fs-OCDD, 1,2,3,4,6,7,8-HpCDD, OCDF and 1,2,3,4,6,7,8-HpCDF. The Cl⁻ emission factor, which is related to the PCDD/F formation, from burning incense was 0.454 mg g^− 1. The resultant lifetime average daily dose and cancer risk for temple workers were 0.00964 pg I-TEQ day^− 1 kg^− 1 and 9.64 × 10^− 6, respectively, approximately 2 times that for residents near the temple (0.00489 pg I-TEQ day^− 1 kg^− 1 and 4.89 × 10^− 6, respectively). We suggest that the chlorine content in incense must be regulated, and the high risk of PCDD/F exposure from burning incense for temple workers and visitors should be of concern.     

Mercury contamination in the vicinity of a chlor-alkali plant and potential risks to local population

A mercury-cell chlor-alkali plant operated in Estarreja (North-western Portugal) for 50 years causing widespread environmental contamination. Although production by this process ceased in 2002, mercury contamination from the plant remains significant. The main objective of this study was to investigate mercury impact on the nearby environment and potential risks to local population. To assess the level of contamination soil samples were collected from agricultural fields in the vicinity of the plant, extending the study by taking samples of the predominant vegetation suitable for animal and human consumption, water samples, and fish species from a nearby coastal lagoon, to gain a preliminary insight into the potential for contamination of the terrestrial and aquatic food web. To determine population exposure to mercury, hair samples were collected from local residents. Total mercury concentration in the 0-15 cm layer of soil was found to be highly variable, ranging between 0.010 and 91 mg kg^− 1, although mercury contamination of soils was found to be restricted to a confined area. Lolium perenne roots contained between 0.0070 and 2.0 mg kg^− 1, and there is evidence that root systems uptake mercury from the soil. Levels of mercury in the aerial parts of plants ranged between 0.018 and 0.98 mg kg^− 1. It appears that plants with higher mercury concentration in soils and roots also display higher mercury concentration in leaves.Total mercury concentration in water samples ranged between 12 and 846 ng L^− 1, all samples presenting concentrations below the maximum level allowable for drinking water defined in the Portuguese law (1.0 μg L^− 1).Mercury levels in fish samples were below the maximum limit defined in the Portuguese law (0.5 mg kg^− 1), ranging from 0.0040 to 0.24 mg kg^− 1. Vegetables collected presented maximum mercury concentration of 0.17 mg kg^− 1. In general, food is not contaminated and should not be responsible for major human exposure to the metal.Mercury determined in human hair samples (0.090-4.2 mg kg^− 1; mean 1.5 mg kg^− 1) can be considered within normal limits, according to WHO guidelines suggesting that it is not affecting the local population. Despite being subject to decades of mercury emissions, nowadays this pollutant is only found in limited small areas and must not constitute a risk for human health, should these areas be restricted and monitored.Considering the present data, it appears that the population from Estarreja is currently not being affected by mercury levels that still remain in the environment.     

Daily intake of manganese by local population around Kylleng Pyndengsohiong Mawthabah (Domiasiat), Meghalaya in India

Present work is carried out adjacent to world's highest rainfall area Kylleng Pyndengsohiong (KP) Mawthabah (Domiasiat), Meghalaya in India to establish the baseline value of manganese intake through dietary route by the local tribe population in view of proposed uranium mining. The locally available food items collected from villages surrounding the proposed uranium mining site at KP Mawthabah (Domiasiat) were analysed using Energy Dispersive X-Ray Fluorescence (EDXRF) Technique. The manganese concentration in different food categories varies from 2.76-12.50 mg kg^− 1 in cereals, 1.8-4.20 mg kg^− 1 in leafy vegetables, 0.30-13.50 mg kg^− 1 in non leafy vegetables, 0.50-15.30 mg kg^− 1 in roots and tubers, 0.70-1.50 mg kg^− 1 in fruits and 0.12-0.96 mg kg^− 1 in flesh food. The mean dietary intake of Mn was found to be 3.83 ± 0.25 mg d^− 1 compared to Recommended Dietary Allowances (RDAs) of 2-5 mg d^− 1. The daily intake of Manganese by the local tribe population is comparable with the value (3.7 mg d^− 1) recommended by International Commission on Radiological Protection (ICRP) for reference man and lower than the intake value observed for Indian and other Asian population.     

Polycyclic aromatic hydrocarbons, elemental and organic carbon emissions from tire-wear

Tire-wear is an important source of PAHs, elemental carbon (EC) and organic carbon (OC). The emissions of these pollutants have been studied in an experimental set-up, simulating a realistic road-tire interaction (summer tire-concrete road). The large particle non-exhaust emissions (LPNE; diameter greater than 10 μm) have been evaluated over 14,500 km run of the tire. An increasing linear trend with cumulative km run was observed for emissions of PAHs and carbon. Amongst PAHs in LPNE, pyrene has been observed to be the highest (30 ± 4 mg kg^− 1) followed by benzo[ghi]perylene (17 ± 2 mg kg^− 1). Different fractions of EC-OC for tire-wear have been analyzed, and unlike exhaust emissions, EC1 was observed to be 99% of EC whereas more than 70% of the OC was the high temperature carbon (OC3 and OC4). The overall emission factors (mass tire^− 1 km^− 1) for PAHs, EC and OC from tire-wear are 378 ng tire^− 1 km^− 1, 1.46 mg tire^− 1 km^− 1 and 2.37 mg tire^− 1 km^− 1 for small cars.     

Emission of CO2 and N2O from soil cultivated with common bean (Phaseolus vulgaris L.) fertilized with different N sources

Addition of different forms of nitrogen fertilizer to cultivated soil is known to affect carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions. In this study, the effect of urea, wastewater sludge and vermicompost on emissions of CO₂ and N₂O in soil cultivated with bean was investigated. Beans were cultivated in the greenhouse in three consecutive experiments, fertilized with or without wastewater sludge at two application rates (33 and 55 Mg fresh wastewater sludge ha^− 1, i.e. 48 and 80 kg N ha^− 1 considering a N mineralization rate of 40%), vermicompost derived from the wastewater sludge (212 Mg ha^− 1, i.e. 80 kg N ha^− 1) or urea (170 kg ha^− 1, i.e. 80 kg N ha^− 1), while pH, electrolytic conductivity (EC), inorganic nitrogen and CO₂ and N₂O emissions were monitored. Vermicompost added to soil increased EC at onset of the experiment, but thereafter values were similar to the other treatments. Most of the NO₃⁻ was taken up by the plants, although some was leached from the upper to the lower soil layer. CO₂ emission was 375 C kg ha^− 1 y^− 1 in the unamended soil, 340 kg C ha^− 1 y^− 1 in the urea-amended soil and 839 kg ha^− 1 y^− 1 in the vermicompost-amended soil. N₂O emission was 2.92 kg N ha^− 1 y^− 1 in soil amended with 55 Mg wastewater sludge ha^− 1, but only 0.03 kg N ha^− 1 y^− 1 in the unamended soil. The emission of CO₂ was affected by the phenological stage of the plant while organic fertilizer increased the CO₂ and N₂O emission, and the yield per plant. Environmental and economic implications must to be considered to decide how many, how often and what kind of organic fertilizer could be used to increase yields, while limiting soil deterioration and greenhouse gas emissions.     

PCDD/Fs and dioxin-like PCBs in home-produced eggs from Belgium: Levels, contamination sources and health risks

This paper discusses the dioxin TEQ levels as determined by the chemically activated luciferase gene expression assay (CALUX) and by HRGC-HRMS in eggs, soils, faeces and kitchen waste samples obtained in the CONTEGG study. The samples were collected in each Belgian province at private homes and in small gardens where chickens are held. The CALUX levels for eggs sampled in autumn were higher than the levels in eggs obtained at the same locations in spring (median values of 5.86 and 4.08 pg CALUX TEQ/g fat, respectively). The total WHO-TEQ levels in eggs, determined by HRGC-HRMS, ranged from 3.29 to 95.35 pg TEQ/g fat in autumn and from 1.50 to 64.79 pg TEQ/g fat in spring. In the soils on which the chickens forage, levels of 2.51-11.35 pg I-TEQ/g in autumn and 2.00-7.86 pg I-TEQ/g in spring were found. The congener pattern of PCDD/Fs in the eggs, soils and faeces was dominated by OCDD, in addition to 1,2,3,4,6,7,8-HeptaCDD, OCDF and 1,2,3,4,6,7,8-HeptaCDF. The predominant dioxin-like PCBs were PCB118, PCB 105 and PCB 156. The dioxin-like PCBs contributed on average 47%, 14% and 20% to the total WHO-TEQ in eggs, soils and faeces, respectively. Kitchen waste samples were very low-contaminated with dioxin-like compounds. The present results showed a good agreement between egg and soil TEQ levels for PCDD/Fs but not for dioxin-like PCBs. This study showed that current soil levels found in some private gardens do not lead to egg levels below the current EU maximal level of 6 pg total TEQ/g fat for dioxins and dioxin-like PCBs. The consumers of the analysed eggs attained 5-79% of the tolerable weekly intake (TWI) of 14 pg TEQ/kg bw for dioxins and dioxin-like PCBs by exposure to their home-produced eggs only.     

Ratio variation of congener profiles of PCDD/Fs and dioxin-like PCBs in human milk during lactation

This study investigates the compositional variations, changes in concentrations and contribution of particular congeners of PCDDs, PCDFs, non-ortho PCBs and mono-ortho PCBs in human milk from two mothers sampled during the 12-month lactation period. Total PCDD/F and dioxin-like PCB concentration in milk sampled from the primiparous mother on day 5 after delivery was 37 pg TEQ/g fat, and this value decreased significantly by 43% at 12 months. In milk sampled from the multiparous mother nursing her second child on day 5 after delivery was 12 pg TEQ/g fat, and this value decreased by 40% at 12 months. The decrease was statistically significant not for PCDD/Fs, but for dioxin-like PCBs. The ratio variance of the congener profiles of PCDD/Fs and dioxin-like PCBs in the milk remained similar during lactation. Moreover, the congener profiles of PCDD/Fs and dioxin-like PCBs in the milk showed similar percentages for both mothers independent of the lactation event and the number of previous births. The mean daily intake of dioxins by the infant nursed by the primiparous mother and the infant nursed by the multiparous mother up to six months of age was 140 and 46 pg TEQ/kg body weight, respectively. From seven to twelve months of age, the mean daily intake was 37 and 13 pg TEQ/kg body weight, respectively. Both values decreased by approximately 70%. The reasons why the mothers' body burden of dioxins decreased by breastfeeding and why the infants' daily intake of human milk per body weight decreased as the infant grows older consequently decreased were considered.     

Nitrogen transformations and greenhouse gas emissions from a riparian wetland soil: an undisturbed soil column study

Riparian wetlands bordering intensively managed agricultural fields can act as biological filters that retain and transform agrochemicals such as nitrate and pesticides. Nitrate removal in wetlands has usually been attributed to denitrification processes which in turn imply the production of greenhouse gases (CO₂ and N₂O). Denitrification processes were studied in the Salburua wetland (northern Spain) by using undisturbed soil columns which were subsequently divided into three sections corresponding to A-, Bg- and B2g-soil horizons. Soil horizons were subjected to leaching with a 200 mg NO₃⁻ L^− 1 solution (rate: 90 mL day^− 1) for 125 days at two different temperatures (10 and 20 °C), using a new experimental design for leaching assays which enabled not only to evaluate leachate composition but also to measure gas emissions during the leaching process. Column leachate samples were analyzed for NO₃⁻ concentration, NH₄⁺ concentration, and dissolved organic carbon. Emissions of greenhouse gases (CO₂ and N₂O) were determined in the undisturbed soil columns. The A horizon at 20 °C showed the highest rates of NO₃⁻ removal (1.56 mg N-NO₃⁻ kg⁻¹ DW soil day^− 1) and CO₂ and N₂O production (5.89 mg CO₂ kg⁻¹ DW soil day^− 1 and 55.71 μg N-N₂O kg⁻¹ DW soil day^− 1). For the Salburua wetland riparian soil, we estimated a potential nitrate removal capacity of 1012 kg N-NO₃⁻ ha^− 1 year^− 1, and potential greenhouse gas emissions of 5620 kg CO₂ ha^− 1 year^− 1 and 240 kg N-N₂O ha^− 1 year^− 1.     

Simultaneous determination of microcystin contaminations in various vertebrates (fish, turtle, duck and water bird) from a large eutrophic Chinese lake, Lake Taihu, with toxic Microcystis blooms

This is the first to conduct simultaneous determination of microcystin (MC) contaminations in multi-groups of vertebrates (fish, turtle, duck and water bird) from Lake Taihu with Microcystis blooms. MCs (-RR, -YR, -LR) in Microcystis scum was 328 μg g^− 1 DW. MCs reached 235 μg g^− 1 DW in intestinal contents of phytoplanktivorous silver carp, but never exceeded 0.1 μg g^− 1 DW in intestinal contents of other animals. The highest MC content in liver of fish was in Carassius auratus (150 ng g^− 1 DW), followed by silver carp and Culter ilishaeformis, whereas the lowest was in common carp (3 ng g^− 1 DW). In livers of turtle, duck and water bird, MC content ranged from 18 to 30 ng g^− 1 DW. High MC level was found in the gonad, egg yolk and egg white of Nycticorax nycticorax and Anas platyrhynchos, suggesting the potential effect of MCs on water bird and duck embryos. High MC contents were identified for the first time in the spleens of N. nycticorax and A. platyrhynchos (6.850 and 9.462 ng g^− 1 DW, respectively), indicating a different organotropism of MCs in birds. Lakes with deaths of turtles or water birds in the literatures had a considerably higher MC content in both cyanobacteria and wildlife than Lake Taihu, indicating that toxicity of cyanobacteria may determine accumulation level of MCs and consequently fates of aquatic wildlife.     

Temporal and spatial distributions of total gaseous mercury concentrations in ambient air in a mountainous area in southwestern China: Implications for industrial and domestic mercury emissions in remote areas in China

Spatial and temporal distributions of total gaseous mercury (TGM) concentrations in ambient air were investigated in the Mt. Gongga area (Sichuan province, PR China) from April 2006 to June 2007. The annual geometric mean TGM concentration at the Moxi baseline station was 3.90 ± 1.20 ng m^− 3. Geometric mean TGM concentrations at 14 representative sampling sites during the warm season ranged from 1.60 to 20.1 ng m^− 3 and varied spatially, with levels decreasing between urbanized areas and more remote regions: urban area (U1-U3: 7.76 ± 4.57 to 20.1 ± 15.1 ng m^− 3), town (T1: 4.61 ± 1.15 ng m^− 3) and village (V1-V4: 3.26 ± 0.63 to 8.45 ± 3.06 ng m^− 3), and remote area (R1-R6: 1.60 ± 0.43 to 3.41 ± 1.26 ng m^− 3). Our study suggested that industrial activities, especially non-ferrous smelting activities, were an important source of atmospheric Hg and played a vital role in the regional distribution of TGM. In addition, domestic coal and biomass combustion to heat residential homes were important sources of TGM in densely populated areas during the winter months.     

Significance and interspecific variability of accumulated trace metal concentrations in Antarctic benthic polychaetes

Trace metals were analysed in polychaetes collected on Polarstern cruise ANT XXI/2 (2003/04) to the Weddell Sea. Pb concentrations were largely less than 1.3 mg kg⁻¹ DW in all samples analysed. Statistical results indicate that the accumulated Cd, Cu and Zn concentrations are related to the feeding guild to which the animals are belonging. Relatively low Cd and Cu concentrations are found in macrophagous carnivores and relatively high concentrations in microphagous detritus feeders. The relationship between Zn concentrations and the feeding guilds of polychaetes is reverse. Cd concentrations range from (median values and interquantile ranges in brackets) 2.6 (1.5-3.2) mg kg⁻¹ DW in the carnivorous Trypanosyllis gigantea to 133 (37-176) mg kg⁻¹ in the microphagous detritus feeder Lanicides bilobata; Cu concentrations from 16 (11-19) mg kg⁻¹ in the carnivorous Antarctinoe spicoides to 40 (23-68) mg kg⁻¹ in the microphagous detritus feeder Phyllocomus crocea and Zn from 89 (69-97) mg kg⁻¹ in the microphagous detritus feeder Isocirrus yungi to 396 (372-404) mg kg⁻¹ in the carnivorous Aglaophamus trissophyllus. Ni is ranging from 3.7 (1.8-6.0) mg kg⁻¹ in Polyeunoa laevis to 34 (20-41) mg kg⁻¹ in A. spicoides, but no significant differences are obvious regarding the feeding guilds. Since information on metals in Antarctic polychaetes is almost completely lacking, our results suggest further studies to clarify the role of feeding in the bioaccumulation of metals in this ecologically important taxonomic group.     

Characteristics of PCDD/F congener distributions in gas/particulate phases and emissions from two municipal solid waste incinerators in Taiwan

Partitioning of PCDD/F (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofuran) congeners between gaseous and particulate phases and removal efficiencies of the existing air pollution control devices (APCDs) for PCDD/Fs at two large-scale municipal waste incinerators (MWIs) in Taiwan are evaluated via stack sampling and analysis. Two MWIs investigated are equipped with activated carbon injection (ACI) and selective catalytic reduction system (SCR) as major PCDD/F control devices, respectively. The average PCDD/F concentrations of stack gases are 2.35 and 1.49 ng/N m(3), and the international toxic equivalent quantity (TEQ) are 0.17 and 0.043 ng TEQ/N m(3) in MWI-A and MWI-B, respectively. The average removal efficiency of PCDD/Fs achieved with ACI+BF (bag filters) reaches 95% (MWI-A) while that achieved with the WS (wet scrubber)+SCR system reaches 99% (MWI-B). The results obtained on gas/particulate partitioning in flue gases indicate that particulate-phase PCDD/Fs accounted for 27.7% and 24.7% of the total PCDD/F concentrations at the outlets of cyclone (CY) and electrostatic precipitator (EP) for MWI-A and MWI-B, respectively. But the gas/particulate partitioning in flue gas after PCDD/Fs control devices is quite different in two MWIs. This study also indicates that total 2,3,7,8-substituted PCDD/F discharges are 142.3 microg TEQ/ton waste for MWI-A and 98.6 microg TEQ/ton waste for MWI-B, respectively.     

Influence of soil properties on trace element availability and plant accumulation in a Mediterranean salt marsh polluted by mining wastes: implications for phytomanagement

The aims of this study were to determine the factors which control metal and As phytoavailability in the different microenvironments (Sand Dunes, Salt Flat, Dry River and Shrubs) present at a Mediterranean salt marsh polluted by mining wastes. We performed a field study following a plot sampling survey. The analyses of soil parameters (pH, electrical conductivity (EC), organic carbon contents, etc.), total metal and As concentrations and their phytoavailability assessed with EDTA were related to each microenvironment and the corresponding plant species uptake. The averages of pH and EC were slightly alkaline (pH ≈ 7.5) and saline (≈ 2.2 to 17.1 dS m⁻¹) respectively. The soil samples from the Salt Flat subzone showed the highest metal concentrations (e.g. 51 mg kg⁻¹ Cd, 11,600 mg kg⁻¹ Pb) while for As, the highest concentrations occurred in the Dry River (380 mg kg⁻¹ As). The total metal and EDTA-extractable concentrations occurred as it follows: Salt Flat > Dry River > Degraded Dunes > Shrubs. In relation to plant metal and As accumulation, the highest root concentrations were obtained in the species from the Salt Flat subzone: ~ 17 mg kg⁻¹ As, ~ 620 mg kg⁻¹ Pb, for both, Juncus maritimus and Arthrocnemum macrostachyum. However the highest metal and As shoot concentrations occurred in species from the Sand Dunes: ~ 23 mg kg⁻¹ As ~ 270 mg kg⁻¹ Pb for Dittrichia viscosa; ~ 23 mg kg⁻¹ As, ~ 390 mg kg⁻¹ Zn for Crucianella maritima. The occurrence of edaphic gradients including salinity and texture determined the vegetation distribution. However, it cannot be concluded that there was a disturbance due to metal(loid)s soil concentrations in terms of vegetation composition except in the Degraded Dunes and Dry River. The higher EDTA-extractable concentrations were coincidental with the most saline soils but this did not result in higher metal(loid)s plant accumulation.     

Environmental impact of mining activities in the Lousal area (Portugal): chemical and diatom characterization of metal-contaminated stream sediments and surface water of Corona stream

Lousal mine is a typical “abandoned mine” with all sorts of problems as consequence of the cessation of the mining activity and lack of infrastructure maintenance. The mine is closed at present, but the heavy metal enriched tailings remain at the surface in oxidizing conditions. Surface water and stream sediments revealed much higher concentrations than the local geochemical background values, which the “Contaminated Sediment Standing Team” classifies as very toxic. High concentrations of Cu, Pb, Zn, As, Cd and Hg occurred within the stream sediments downstream of the tailings sites (up to: 817 mg kg⁻¹ As, 6.7 mg kg⁻¹ Cd, 1568 mg kg⁻¹ Cu, 1059 mg kg⁻¹ Pb, 82.4 mg kg⁻¹ Sb, 4373 mg kg⁻¹ Zn). The AMD waters showed values of pH ranging from 1.9 to 2.9 and concentrations of 9249 to 20,700 mg L⁻¹ SO₄⁻², 959 to 4830 mg L⁻¹ Fe and 136 to 624 mg L⁻¹ Al. Meanwhile, the acid effluents and mixed stream waters also carried high contents of SO₄^2−, Fe, Al, Cu, Pb, Zn, Cd, and As, generally exceeding the Fresh Water Aquatic Life Acute Criteria. Negative impacts in the diatom communities growing at different sites along a strong metal pollution gradient were shown through Canonical Correspondence Analysis: in the sites influenced by Acid Mine Drainage (AMD), the dominant taxon was Achnanthidium minutissimum. However, Pinnularia acoricola was the dominant species when the environmental conditions were extremely adverse: very low pH and high metal concentrations (sites 2 and 3). Teratological forms of Achnanthidium minutissimum (Kützing) Czarnecki, Brachysira vitrea (Grunow) Ross in Hartley, Fragilaria rumpens (Kützing) G. W. F. Carlson and Nitzschia hantzschiana Rabenhorst were found. A morphometric study of B. vitrea showed that a decrease in size was evident at the most contaminated sites. These results are evidence of metal and acidic pollution.     

Responses of streams in central Appalachian Mountain region to reduced acidic deposition—Comparisons with other regions in North America and Europe

Data from 5 wet deposition stations and 21 streams during 1980-2006 were analyzed to investigate chemical responses of streams to reduced acidic deposition in the central Appalachian Mountain region of West Virginia, USA. Wet deposition of acidic anions (i.e., sulfate, nitrate, and chloride) and hydrogen ions decreased significantly during the studied time period. Stream sulfate showed a delayed response to the reduced acidic deposition, and showed a decrease in the 2000s (− 5.54 µeq L^− 1 yr^− 1) and the whole period (− 0.49 µeq L^− 1 yr^− 1). No significant trend of stream nitrate + nitrite and chloride was observed. Stream alkalinity increased in the 1990s (+ 23.33 µeq L^− 1 yr^− 1) and the whole period (+ 7.26 µeq L^− 1 yr^− 1). Stream hydrogen ions decreased in the 1990s (− 0.002 µeq L^− 1 yr^− 1), 2000s (− 0.001 µeq L^− 1 yr^− 1), and the whole period (− 0.001 µeq L^− 1 yr^− 1). Compared with most acidic streams and lakes in the United States and Europe, a lower decreasing rate of hydrogen ions and higher increasing rate of alkalinity were observed in the alkaline West Virginian streams in the 1990s. However, due to their initial negative or zero alkalinity values, those acidic streams showed a higher percent increase in alkalinity than that in the alkaline West Virginian streams (from 800 µeq L^− 1 yr^− 1 to 1200 µeq L^− 1 yr^− 1). Total aluminum in the West Virginian streams decreased in the 1990s (− 0.67 µmol L^− 1 yr^− 1) and the whole period (− 0.22 µmol L^− 1 yr^− 1). The current study advanced our understanding of streams' responses to the reduced acidic deposition in the Mid-Appalachians since the passage of the 1970 and 1990 Amendments to the United States Clean Air Act (US CAAA).     

Copper clean-up procedure for ultrasonic extraction and analysis of pyrethroid and phenylpyrazole pesticides in sediments by gas chromatography-electron capture detection

A rapid ultrasonic extraction method coupled with a heated-copper clean-up procedure for removing interfering constituents was developed for analyzing pyrethroid and phenylpyrazole pesticides in sediments. Incubation of the 60 mL extract with 12 g copper granules at 60 °C for 2 h was determined to be the optimal conditions for removing the interfering constituents. Eleven pyrethroid and phenylpyrazole pesticides were spiked into sediment samples to determine the effectiveness of the ultrasonic extraction method. The average recoveries of pyrethroids and phenylpyrazoles in sediment at 4 °C storage on day 0, 1, 7, 14, and 21 ranged from 98.6 to 120.0%, 79.2 to 116.0%, 85.0 to 119.7%, 93.6 to 118.7%, and 92.1 to 118.2%, respectively, with all percent relative standard deviations less than 10% (most < 6%). This illustrated the stability of pyrethroids and phenylpyrazoles in sediment during sediment aging at 4 °C. Recoveries of the pesticides ranged from 98.6% to 120.0% for lowest fortification level (2-16 μg kg⁻¹), from 97.8% to 117.9% for middle fortification level (10-80 μg kg⁻¹), and from 94.3% to 118.1% for highest fortification level (20-160 μg kg⁻¹). Relative standard deviations of pesticide recoveries were usually less than 7%. Method detection limits of target pesticides ranged from 0.22 μg kg⁻¹ to 3.72 μg kg⁻¹. Furthermore, field sediment samples collected from four residential lakes during a three-month monitoring period were analyzed to evaluate the effectiveness of this method. Bifenthrin was detected in all of sediment samples (highest concentration 260.33 ± 41.71 μg kg⁻¹, lowest concentration 5.68 ± 0.38 μg kg⁻¹), and fipronil sulfone was detected at least once in sediment samples collected from three sites with concentrations ranging from 1.73 ± 0.53 to 7.53 ± 0.01 μg kg⁻¹.     

Deforestation and greenhouse gas emissions associated with fuelwood consumption of the brick making industry in Sudan

The study focuses on the role of the fired clay brick making industry (BMI) on deforestation and greenhouse gas (GHG) emissions in Sudan. The BMI is based on numerous kilns that use biomass fuel, mainly wood which is largely harvested unsustainably. This results in potential deforestation and land degradation. Fuelwood consumption data was collected using interviews and questionnaires from 25 BMI enterprises in three administrative regions, namely Khartoum, Kassala and Gezira. Annual fuelwood consumption data (t dm yr^− 1) was converted into harvested biomass (m³) using a wood density value of 0.65 t dm m^− 3. For annual GHG estimations, the methodological approach outlined by the Intergovernmental Panel on Climate Change (IPCC) was used. According to our results, the annual deforestation associated with the BMI for the whole of Sudan is 508.4 × 10³ m³ of wood biomass, including 267.6 × 10³ m³ round wood and 240.8 × 10³ m³ branches and small trees. Total GHG emissions from the Sudanese BMI are estimated at 378 028 t CO₂, 15 554 t CO, 1778 t CH₄, 442 t NO_X, 288 t NO and 12 t N₂O per annum. The combined CO₂-equivalent (global warming potential for 100-year time horizon) of the GHG emissions (excluding NO_X and NO) is 455 666 t yr^− 1. While these emissions form only a small part of Sudan's total GHG emissions, the associated deforestation and land degradation is of concern and effort should be made for greater use of sustainable forest resources and management.     

Pharmaceutical and personal care products in tile drainage following surface spreading and injection of dewatered municipal biosolids to an agricultural field

Land application of municipal biosolids can be a source of environmental contamination by pharmaceutical and personal care products (PPCPs). This study examined PPCP concentrations/temporally discrete mass loads in agricultural tile drainage systems where two applications of biosolids had previously taken place. The field plots received liquid municipal biosolids (LMB) in the fall of 2005 at an application rate of ∼ 93,500 L ha^− 1, and a second land application was conducted using dewatered municipal biosolids (DMB) applied at a rate of ∼ 8 Mt dw ha^− 1 in the summer of 2006. The DMB land application treatments consisted of direct injection (DI) of the DMB beneath the soil surface at a nominal depth of ∼ 0.11 m, and surface spreading (SS) plus subsequent tillage incorporation of DMB in the topsoil (∼ 0.10 m depth). The PPCPs examined included eight pharmaceuticals (acetaminophen, fluoxetine, ibuprofen, gemfibrozil, naproxen, carbamazepine, atenolol, sulfamethoxazole), the nicotine metabolite cotinine, and two antibacterial personal care products triclosan and triclocarban. Residues of naproxen, cotinine, atenolol and triclosan originating from the fall 2005 LMB application were detected in tile water nearly nine months after application (triclocarban was not measured in 2005). There were no significant differences (p > 0.05) in PPCP mass loads among the two DMB land application treatments (i.e., SS vs. DI); although, average PPCP mass loads late in the study season (> 100 days after application) were consistently higher for the DI treatment relative to the SS treatment. While the concentration of triclosan (∼ 14,000 ng g^− 1 dw) in DMB was about twice that of triclocarban (∼ 8000 ng g^− 1 dw), the average tile water concentrations for triclosan were much higher (43 ± 5 ng L^− 1) than they were for triclocarban (0.73 ± 0.14 ng L^− 1). Triclosan concentrations (maximum observed in 2006 ∼ 235 ng L^− 1) in tile water resulting from land applications may warrant attention from a toxicological perspective.     

Effects of water regime during rice-growing season on annual direct N2O emission in a paddy rice-winter wheat rotation system in southeast China

Annual paddy rice-winter wheat rotation constitutes one of the typical cropping systems in southeast China, in which various water regimes are currently practiced during the rice-growing season, including continuous flooding (F), flooding-midseason drainage-reflooding (F-D-F), and flooding-midseason drainage-reflooding and moisture but without waterlogging (F-D-F-M). We conducted a field experiment in a rice-winter wheat rotation system to gain an insight into the water regime-specific emission factors and background emissions of nitrous oxide (N₂O) over the whole annual cycle. While flooding led to an unpronounced N₂O emission during the rice-growing season, it incurred substantial N₂O emission during the following non-rice season. During the non-rice season, N₂O fluxes were, on average, 2.61 and 2.48 mg N₂O-N m⁻² day^− 1 for the 250 kg N ha^− 1 applied plots preceded by the F and F-D-F water regimes, which are 56% and 49% higher than those by the F-D-F-M water regime, respectively. For the annual rotation system experienced by continuous flooding during the rice-growing season, the relationship between N₂O emission and nitrogen input predicted the emission factor and background emission of N₂O to be 0.87% and 1.77 kg N₂O-N ha^− 1, respectively. For the plots experienced by the water regimes of F-D-F and F-D-F-M, the emission factors of N₂O averaged 0.97% and 0.85%, with background N₂O emissions of 2.00 kg N₂O-N ha^− 1 and 1.61 kg N₂O-N ha^− 1 for the annual rotation system, respectively. Annual direct N₂O-N emission was estimated to be 98.1 Gg yr^− 1 in Chinese rice-based cropping systems in the 1990s, consisting of 32.3 Gg during the rice-growing season and 65.8 Gg during the non-rice season, which accounts for 25-35% of the annual total emission from croplands in China.     

Nitrifier characteristics in submerged membrane bioreactors under different sludge retention times

Three submerged membrane bioreactors (MBRs) were operated continuously for 230 days by feeding with synthetic inorganic wastewater (NH₄⁺-N, 100 mg L⁻¹) under different solids retention times (SRTs. M_30d, 30 days; M_90d, 90 days; M_infinite, no sludge purge) to examine the influence of SRT on nitrification performance and microbial characteristics. All the reactors could oxidize NH₄⁺-N to NO₃⁻-N effectively without accumulation of NO₂⁻-N. M_30d with the shortest SRT showed significantly higher specific ammonium oxidizing rate (SAOR, 0.22 kg NH₄⁺-N kg⁻¹ MLSS day⁻¹) and specific nitrate forming rate (SNFR, 0.13 kg NO₃⁻-N kg⁻¹ MLSS day⁻¹) than the other two MBRs (0.12-0.14 kg NO₃⁻-N kg⁻¹ MLSS day⁻¹ and 0.042-0.068 kg NO₃⁻-N kg⁻¹ MLSS day⁻¹, respectively). Short SRT led to low extracellular polymeric substances (EPS) concentration and long operating cycle. The nitrite oxidizing bacteria (NOB) ratios by both the fluorescence in situ hybridization (FISH) (3.6% for M_30d and 2.1-2.2% for M_90d and M_infinite) and MPN (1.4 × 10⁷ cells g⁻¹ MLSS for M_30d and 6.2 × 10⁵ and 2.7 × 10⁴ cells g⁻¹ MLSS for M_90d and M_infinite) analyses showed that M_30d favored the accumulation of NOB, which was in accordance with the SNFR result. However, the ammonia oxidizing bacteria (AOB) ratios (3.5%, 3.2% and 4.9% for M_30d, M_90d and M_infinite) were not in accordance with the SAOR result. PCR-DGGE, clone library and FISH results showed that the fast-growing Nitrosomonas and Nitrobacter sp. were the dominant AOB and NOB, respectively for M_30d, while considerable slow-growing Nitrosospira and Nitrospira sp. existed in M_infinite, which might be an important reason why M_infinite had a low SAOR and SNFR.