Survival of Escherichia coli O157:H7 in soils under different land use types

Laboratory studies on Escherichia coli O157:H7 survival in soils from four different land use types: forest, tea plantation, bamboo grove, and vegetable garden were investigated at 25?±?1 °C with the field capacity (soil water content at ?33 kPa). Results showed that E. coli O157:H7 declined quickly in the test soils, but its survival dynamics varied in the soils under different land use types. The survival time needed to reach the detection limit (t _d) in the test soils ranged from 2.1 to 3.6 days, with slightly longer t _d values being observed in soils from the bamboo grove. Stepwise multiple regression analysis revealed that the t _d values were shorter in sandy, lower pH, and lower organic carbon content soils. Different E. coli O157:H7 survival time in the soils under different land uses suggests that it is important to adapt proper management practices for reducing the potential risks of pathogen contamination when diary manure is applied to agricultural land.     

Habitat use by giant panda in relation to man-made forest in Wanglang Nature Reserve of China

To evaluate the effectiveness of human restoration in species conservation, in this study, we undertook a field survey of giant panda (Ailuropoda melanoleuca) habitat and man-made forest habitat in Wanglang Nature Reserve of China. Our results revealed that giant panda did not use the man-made forest in this area so far, and that there were significant differences between the giant panda habitat and the man-made forest habitat. Compared with giant panda habitat, the man-made forest habitat was characterized by lower shrub coverage, thinner trees and lower bamboo density. To improve the effectiveness of human restoration, the habitat requirement of giant panda should be fully consider in the whole process of habitat restoration.     

Surface runoff and nitrogen (N) loss in a bamboo (Phyllostachys pubescens) forest under different fertilization regimes

Nitrogen (N) losses from agricultural fields have been extensively studied. In contrast, surface runoff and N losses have rarely been considered for bamboo forests that are widespread in regions such as southern China. The thriving of bamboo industries has led to increasing fertilizer use in bamboo forests. In this study, we evaluated surface runoff and N losses in runoff following different fertilization treatments under field conditions in a bamboo (Phyllostachys pubescens) forest in the catchment of Lake Taihu in Jiangsu, China. Under three different fertilization regimes, i.e., control, site-specific nutrient management (SSNM), and farmer's fertilization practice (FFP), the water runoff rate amounted to 356, 361, and 342 m³?ha^?1 and accounted for 1.91, 1.98, and 1.85 % of the water input, respectively, from June 2009 to May 2010. The total N losses via surface runoff ranged from 1.2 to 1.8 kg?ha^?1. Compared with FFP, the SSNM treatment reduced total nitrogen (TN) and dissolved nitrogen (DN) losses by 31 and 34 %, respectively. The results also showed that variations in N losses depended mainly on runoff fluxes, not N concentrations. Runoff samples collected from all treatments throughout the year showed TN concentrations greater than 0.35 mg?L^?1, with the mean TN concentration in the runoff from the FFP treatment reaching 8.97 mg?L^?1. The loss of NO₃ ^?–N was greater than the loss of NH₄ ⁺–N. The total loss of dissolved organic nitrogen (DON) reached 23–41 % of the corresponding DN. Therefore, DON is likely the main N species in runoff from bamboo forests and should be emphasized in the assessment and management of N losses in bamboo forest.     

Effects of silicon and copper on bamboo grown hydroponically

Due to its high growth rate and biomass production, bamboo has recently been proven to be useful in wastewater treatment. Bamboo accumulates high silicon (Si) levels in its tissues, which may improve its development and tolerance to metal toxicity. This study investigates the effect of Si supplementation on bamboo growth and copper (Cu) sensitivity. An 8-month hydroponic culture of bamboo Gigantocloa sp. “Malay Dwarf ” was performed. The bamboo plants were first submitted to a range of Si supplementation (0–1.5 mM). After 6 months, a potentially toxic Cu concentration of 1.5 μM Cu²⁺ was added. Contrary to many studies on other plants, bamboo growth did not depend on Si levels even though it absorbed Si up to 218 mg g^?1 in leaves. The absorption of Cu by bamboo plants was not altered by the Si supplementation; Cu accumulated mainly in roots (131 mg kg^?1), but was also found in leaves (16.6 mg kg^?1) and stems (9.8 mg kg^?1). Copper addition did not induce any toxicity symptoms. The different Cu and Si absorption mechanisms may partially explain why Si did not influence Cu repartition and concentration in bamboo. Given the high biomass and its absorption capacity, bamboo could potentially tolerate and accumulate high Cu concentrations making this plant useful for wastewater treatment.     

Selection and Implementation of a Flagship Fleet in a Locally Undervalued Region of High Endemicity

Flagships are one conservation education tool. We present a proposed flagship species fleet for environmental education in central Chile. Our methods followed recent flagship guidelines. We present our selection process and a detailed justification for the fleet of flagship species that we selected. Our results are a list of eight flagship species forming a flagship fleet, including two small- and medium-sized mammals, the degu (Octodon degus) and the culpeo fox (Lycalopex culpeaus), two birds, the turca (Pteroptochos megapoidius) and the burrowing owl (Athene cunicularia), the Chilean iguana (Calopistes palluma), the tarantula (Grammostola mollicoma), and two trees, the litre (Lithrea caustica) and the espino (Acacia caven). We then describe how these flagships can be deployed most effectively, describing their audience, effective narrative frames, and modes of presentation. We conclude that general selection rules paired with social science background data allow for an efficient selection process.     

Reactive plume model: Effect of stack exit conditions on gas phase precursors and sulfate formation

A simple form of a carbon-bond smog mechanism has been introduced into a complete set of plume conservation equations. The conservation expressions for mass, momentum, energy and component species have been solved numerically for typical source and neutral or adiabatic ambient conditions to simulate the homogeneous gas phase chemistry for approximately two hours of travel time downwind from the stack exit. The influence of stack exit conditions including the ratios of momentum-to-buoyancy length l_m/l_b, source-to-ambient velocity R and mixing-to-reaction time τ are demonstrated.It was found that homogeneous processes in the plume near-field do not significantly contribute to the overall conversion of SO₂ to SO²⁻₄. In the far-field maximum sulfate formation rates of 2.3% h⁻¹ were predicted for clear summer noon hours, consistent with plume measurements. Variation of stack exit conditions were found to have little effect on the maximum SO₂ conversion rate or the peak OH radical concentration where local HC/NO_x ratios between 16 and 22 were predicted. Parameter changes resulting in greater ambient entrainment rates, however, were found to shift the development of the radical pool closer to the source and to significantly increase the total molar flux of plume sulfate.     

Positive Interactions Between Irrawaddy Dolphins and Artisanal Fishers in the Chilika Lagoon of Eastern India are Driven by Ecology,Socioeconomics, and Culture

In human-dominated landscapes, interactions and perceptions towards wildlife are influenced by multidimensional drivers. Understanding these drivers could prove useful for wildlife conservation. We surveyed the attitudes and perceptions of fishers towards threatened Irrawaddy dolphins (Orcaella brevirostris) at Chilika Lagoon India. To validate the drivers of fisher perceptions, we : (1) observed dolphin foraging behavior at stake nets, and (2) compared catch per unit effort (CPUE) and catch income of fishers from stake nets in the presence and absence of foraging dolphins. We found that fishers were mostly positive towards dolphins, believing that dolphins augmented their fish catch and using culture to express their perceptions. Foraging dolphins were observed spending half their time at stake nets and were associated with significantly higher catch income and CPUE of mullet (Liza sp.), a locally preferred food fish species. Wildlife conservation efforts should use the multidimensional drivers of human–wildlife interactions to involve local stakeholders in management.     

Cadmium tolerance in six poplar species

Selection of poplar species with greater Cd tolerance and exploiting the physiological mechanisms involved in Cd tolerance are crucial for application of these species to phyto-remediation. The aim of this study is to investigate variation in Cd tolerance among the six poplar species and its underlying physiological mechanisms. Cuttings of six Populus species were cultivated for 10 weeks before exposure to either 0 or 200 μM CdSO₄ for 20 days. Gas exchange in mature leaves was determined by a portable photosynthesis system. Cd concentrations in tissues were analyzed by a flame atomic absorbance spectrometry. Subsequently, Cd amount per plant, bio-concentration factor (BCF) and translocation factor (T _f) were calculated. Nonenzymatic compounds and activities of antioxidative enzymes in tissues were analyzed spectrophotometrically. Cd exposure caused decline in photosynthesis in four poplar species including Populus cathayana (zhonghua 1). Among the six species, P. cathayana (zhonghua 1) displayed the highest Cd concentrations in tissues, the largest Cd amount in aerial parts, the highest BCF in aerial parts and T _f under Cd exposure. Under Cd stress, increases in total soluble sugars in roots but decreases in starch in roots, wood, and leaves of P. cathayana (zhonghua 1) were found. Induced O ₂ ^?? and H₂O₂ production in roots and leaves, and increases in free proline, soluble phenolics, and activities of antioxidative enzymes were observed in P. cathayana (zhonghua 1). Based on results of this pot experiment, it is concluded that P. cathayana (zhonghua 1) is superior to other five species for Cd phyto-remediation, and its well-coordinated physiological changes under Cd exposure confer the great Cd tolerance of this species.     

Comparison of two wild rodent species as sentinels of environmental contamination by mine tailings

Background

Contamination with heavy metals is among the most hazardous environmental concerns caused by mining activity. A valuable tool for monitoring these effects is the use of sentinel organisms. Particularly, small mammals living inside mine tailings are an excellent study system because their analysis represents a realistic approach of mixtures and concentrations of metal exposure.

Purpose

We analyzed metal tissue concentrations and DNA damage levels for comparison between genders of a sentinel (Peromyscus melanophrys) and a nonsentinel (Baiomys musculus) species. Also, the relationship between DNA damage and the distance from the contamination source was evaluated.

Methods

This study was conducted in an abandoned mine tailing at Morelos, Mexico. Thirty-six individuals from both species at the exposed and reference sites were sampled. Metal concentrations in bone and liver of both species were analyzed by atomic absorption spectrophotometry, and DNA damage levels were assayed using the alkaline comet assay.

Results

In general, concentrations of zinc, nickel, iron, and manganese were statistically higher in exposed individuals. A significant effect of the organ and the site on all metal tissue concentrations was detected. Significant DNA damage levels were registered in the exposed group, being higher in B. musculus. Females registered higher DNA damage levels than males. A negative relationship between distance from the mine tailing and DNA damage in B. musculus was observed.

Conclusions

We consider that B. musculus is a suitable species to assess environmental quality, especially for bioaccumulable pollutants??such as metals??and recommend that it may be considered as a sentinel species.     

Health risk assessment for consumption of fish originating from ponds near Dabaoshan mine, South China

Mining effluents are a potential source of toxic metals in the surrounding aquatic ecosystem and pose a potential health risk to humans from fish consumption. The objective of this paper is to assess the impact of the long-term Dabaoshan mining operation on heavy metal accumulation in different fish species. Heavy metal accumulation (lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu)) in four tissues (liver, muscle, intestine, and gills) of five carp species (Hypophthalmichthys molitrix, Ctenopharyngodon idellus, Megalobrama amblycephala, Aristichthys nobilis, and Carassius auratus auratus) from two fishponds exposed to effluent waters from Dabaoshan mine, South China. The bioaccumulation factor (BAF) and target hazard quotients were calculated to assess potential health risks to local residents through fish consumption. Levels of heavy metals varied depending on the analyzed tissues. C. auratus auratus accumulated the higher Pb, Cd, Zn, and Cu in the intestine compared with other fish species. Liver of all five species contained high concentrations of Pb, Cd, Zn, and Cu. The BAF for the studied metals showed a descending order of Cd?>?Zn?>?Cu?>?Pb for fishpond 1 and Zn?>?Cd?>?Cu?>?Pb for fishpond 2. Risk assessments suggested that potential human health risk may be present due to high Pb and Cd concentration in the muscle of some fish species exceeding the national and international limits, although the target hazard quotients were less than one.     

Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline

Between 18 March and 27 October 2002, 220 air samples were collected on 209 of 224 calendar days, on top of a coastal atmospheric research tower in Erdemli, Turkey. The volume of air filtered for each sample was 340 liters. Two hundred fifty-seven bacterial and 2598 fungal colony forming units (CFU) were enumerated from the samples using a low-nutrient agar. Ground-based dust measurements demonstrated that the region is routinely impacted by dust generated regionally and from North Africa and that the highest combined percent recovery of total CFU and African dust deposition occurred in the month of April (93.4% of CFU recovery and 91.1% of dust deposition occurred during African dust days versus no African dust present, for that month). A statistically significant correlation was observed (peak regional African dust months of March, April and May; r_s=0.576, P=0.000) between an increase in the prevalence of microorganisms recovered from atmospheric samples on dust days (regional and African as determined by ground-based dust measurements), versus that observed on non-dust days. Given the prevalence of atmospherically suspended desert dust and microorganisms observed in this study, and that culture-based studies typically only recover a small fraction (<1.0%) of the actual microbial population in any given environment, dust-borne microorganisms and other associated constituents (organic detritus, toxins, etc.) may play a significant role in the regional human and ecosystem health.     

People and biodiversity in the 21st century: This article belongs to Ambio’s 50th Anniversary Collection. Theme: Biodiversity conservation

Fifty years have elapsed since the first publication of Ambio. Throughout this period, fundamental changes have occurred in societal attitudes to biodiversity conservation. Ambio has published numerous papers that have aligned with these new approaches. High citations numbers suggest that Ambio papers have had a significant impact on conservation strategies. We review these publications and find that they align well with changed societal perspectives on biodiversity. Ambio papers have called for greater contributions of local and indigenous peoples and for conservation in multi-functional landscapes. The 1992 Convention on Biological Diversity built on these principles. Negotiations are now underway for a post-2020 framework for biodiversity. Ambio papers have argued for a stronger scientific basis for conservation and for the need to adapt to changing conditions and to the rich diversity of societal preferences for conservation. International processes favor simple, generalizable approaches to conservation but we call for recognition of the diversity of ecological and human conditions in which conservation occurs. There is a need to build capacity to support a diversity of conservation approaches that are adapted to changing local conditions and to the priorities of diverse human societies.     

Comparative analysis of the growth impact of pollution and energy use in selected West African nations

We adopt the FMOLS and Granger causality technique to analyse the effect of energy use and carbon emissions on output growth in selected West African economies, which includes Nigeria, Gambia and Ghana, from 1970 to 2019. Findings confirm that energy use enhances growth in the three selected West African economies. But in terms of significance, energy consumption is significant in Nigeria and Gambia at a 1% level of significance while it is insignificant for the Gambia. CO₂ emission positively and significantly propels economic growth for the three selected West African economies. For Nigeria, causality evidence shows no direct influence among the variables. For Ghana, we find a bi-causal association between output growth and carbon emissions and a unidirectional causality from pollution to energy consumption. For Gambia, economic growth causes CO₂ emissions. We recommend that the West African government reinforce their stand on a sustainable growth path through energy conservation.

     

Primary source attribution and analysis of α-pinene photooxidation products in Duke Forest,North Carolina

Samples of fine particulate organic matter were collected outside Durham, NC in the Duke Research Forest as part of the CELTIC study in July 2003. Particulate samples were collected on quartz filters using high volume air sampling equipment, and samples were analyzed for polar and non-polar organic species. Among compounds analyzed, oxidation products of α-pinene, namely pinic acid and pinonic acid, were identified in all samples. Pinic acid, being a dicarboxylic acid, has a low vapor pressure of the order of 10⁻⁸ Torr and is expected to contribute significantly to secondary organic aerosol (SOA) formation from the oxidation of α-pinene. Source contribution estimates from primary organic aerosol emissions were computed using the organic species as molecular markers with the chemical mass balance (CMB) model. The unapportioned organic carbon (OC) was determined as the difference between measured OC and OC apportioned to primary sources. This unapportioned OC was then correlated with pinic and pinonic acid to get a better understanding of the role of monoterpene oxidation products to form SOA. A reasonably good fit between pinic acid concentrations and unapportioned OC levels is indicative of the contribution of α-pinene oxidation products to SOA formation in ambient atmosphere. The results are significant considering the role of monoterpene emissions to global atmospheric chemistry.     

Semivolatile behavior of dicarboxylic acids and other polar organic species at a rural background site (Nylsvley,RSA)

In this study aerosol samples from the South African savanna were analyzed for their polar organic constituents. Samples were collected with a front/back-up filter tandem system of quartz fiber filters (dual filter strategy). In all samples (n=15) dicarboxylic acids and a variety of phthalates, aldehydes and monocarboxylic acids were observed. Oxalic acid was the dominating compound with an average amount of 79.2 ng m⁻³ on the front filter and 11.3 ng m⁻³ on the back-up filter. The presence of significant concentrations of dicarboxylic acids on the back-up filter was rather unexpected. There are two possible sources to explain the presence of individual compounds on the back-up filter – particle penetration through the front filter or adsorption of compound parts from the gas phase. Interpretation of the data indicates that the dicarboxylic acid concentrations on the back-up filters appear to be caused by the adsorption of gaseous organic species. Dicarboxylic acids semivolatilic behavior is evident with this results. This conclusion refutes the commonly held view that dicarboxylic acids in the atmosphere were associated with the aerosol phase only. Additionally, it was found that the distribution of dicarboxylic acids between the gas and particle phase in the atmosphere is not only dependent on their vapor pressures. The actual gas phase concentration appears to be more determined by the chemical properties of the particles than by pure physical influences. Surprisingly, malonic acid exhibits an anomaly, as it does not show a semivolatile tendency.     

Effect of Zn toxicity on root morphology,ultrastructure, and the ability to accumulate Zn in Moso bamboo (Phyllostachys pubescens)

The effects of zinc (Zn) on seed germination and growth of Moso bamboo (Phyllostachys pubescens) were investigated. Under zinc stress, the seed germination rate did not show significant difference from that of the control. Hydroponics experiments indicated that Moso bamboo had a strong ability to accumulate Zn in the shoot and it reached its maximum value in the shoot at 100 μM Zn. The root Zn concentration ranged from 2,329.29 to 8,642.51 mg kg^?1, with the root Zn concentration at 10 μM Zn being 58.23 times that of the control. The root morphology parameters slightly increased at the lower Zn treatments, while growth restriction was evident at higher Zn treatments. Root ultrastructural studies revealed that the cell structure, root tips, and organelles were significantly changed under Zn stress as compared to those of the control. Some abnormalities were evident in the cell walls, vacuoles, mitochondria, plasmalemma, tonoplast, and xylem parenchyma of root cells. While Moso bamboo seems a suitable candidate for phytoremediation, its metal remediation ability should be further explored in future investigations.     

Impact of different land uses on polycyclic aromatic hydrocarbon contamination in coastal stream sediments

PAHs are ubiquitous environmental pollutants that can cause adverse health and ecological effects. In the present study, we examined the impact of land use on the concentration and composition of PAHs in 28 coastal stream sediments on the Island of Oahu, Hawaii. In densely populated urban areas, the concentration range of total PAHs in the stream sediments affected by mixed residential and industrial activities (RI) are 0.40-9.05 ppm, which is significantly higher than the 0.36-4.21 ppm detected in the stream sediments affected predominantly by urban residential land uses (UR). The stream sediments affected by agricultural activities (AG) reported a concentration range of 0.09-2.14 ppm, which is lower than those of the RI and UR stream sediments. The molecular weight of PAH is a factor, as only high molecular weight (HMW) PAHs were significantly affected by land uses (ANOVA P = 0.009). Correlation analysis showed that only in the UR stream sediments were significant correlations observed between PAH concentration and two anthropogenic indicators: population density (r = 0.57, P = 0.027) and vehicle density (r = 0.55, P = 0.034). The fractional concentrations of PAHs were analyzed by using PCA analysis, which led to the separate clustering of the RI and AG stream sediments and suggest distinct PAH sources between the two land uses. Two PAH source indicators, including Ant/(Ant + Phe) and Fl/(Fl + Py), indicates that PAHs sources in the RI stream sediments are most likely of petroleum origin, while PAHs in the UR and AG stream sediments most likely came from combustion activities. In addition, the concentration and relative potency of carcinogenic PAHs in the coastal stream sediments exhibited similar patterns as the total PAH concentration with respect to land uses.     

A methodology for the quantification of the net African dust load in air quality monitoring networks

This paper proposes and validates a methodology for the quantification of the daily African PM load during dust outbreaks in southern Europe. The daily net dust load in PM10 attributable to an African episode in a given region can be obtained by subtracting the daily regional background (RB) level from the PM10 concentration value at an RB station. As demonstrated in this paper, the daily RB level can be obtained by applying a monthly moving 30th percentile to the PM10 time series at an RB station after a prior extraction of the data of the days with African dust transport. The daily PM10 RB levels obtained can be subtracted from the daily PM10 levels recorded at the same RB site only on days when the occurrence of African dust outbreaks was demonstrated, the difference being the daily net African dust load. It is thus possible to quantify the African dust contribution during an African PM event in southern Europe without the need for PM speciation.The validation of this methodology was performed by comparing the estimated net dust load during African dust outbreaks at three RB stations and the crustal load determined by chemical speciation of PM10 filters. The correlation (r²>0.6) and the equivalence (correlation lines’ slopes ∼1) were significant in the three cases.     

Spatial distribution of ciguateric fish in the Republic of Kiribati

Ciguatera is food poisoning caused by human consumption of reef fish contaminated with ciguatoxins (CTXs). The expanding international trade of tropical fish species from ciguatera-endemic regions has resulted in increased global incidence of ciguatera, and more than 50 000 people are estimated to suffer from ciguatera each year worldwide. The Republic of Kiribati is located in the Pacific Ocean; two of its islands, Marakei and Tarawa, have been suggested as high-risk areas for ciguatera. The toxicities of coral reef fish collected from these islands, including herbivorous, omnivorous and carnivorous fish (24% [n = 41], 8% [n = 13] and 68% [n = 117], respectively), were analyzed using the mouse neuroblastoma assay (MNA) after CTX extraction. The MNA results indicated that 156 fish specimens, or 91% of the fish samples, were ciguatoxic (CTX levels >0.01 ng g⁻¹). Groupers and moray eels were generally more toxic by an order of magnitude than other fish species. All of the collected individuals of eight species (n = 3-19) were toxic. Toxicity varied within species and among locations by up to 10 000-fold. Cephalapholis argus and Gymnothorax spp. collected from Tarawa Island were significantly less toxic than those from Marakei Island, although all individuals were toxic based on the 0.01 ng g⁻¹ threshold. CTX concentrations in the livers of individuals of two moray eel species (Gymnothorax spp., n = 6) were nine times greater than those in muscle, and toxicity in liver and muscle showed a strong positive correlation with body weight. The present study provides quantitative information on the ciguatoxicity and distribution of toxicity in fish for use in fisheries management and public health.