Batch and continuous biosorption of Cu by immobilized biomass of Arthrobacter sp.

The ability of free and polysulphone immobilized biomass of Arthrobacter sp. to remove Cu²⁺ ions from aqueous solution was studied in batch and continuous systems. The Langmuir and Freundlich isotherm models were applied to the data. The Langmuir isotherm model was found to fit the sorption data indicating that sorption was monolayer and uptake capacity (Q^o) was 175.87 and 158.7 mg/g for free and immobilized biomass respectively at pH 5.0 and 30 °C temperature, which was also confirmed by a high correlation coefficient, a low RMSE and a low Chi-square value. A kinetic study was carried out with pseudo-first-order reaction and pseudo-second-order reaction equations and it was found that the Cu²⁺ uptake process followed the pseudo-second-order rate expression. The diffusivity of Cu²⁺ on immobilized beads increased (0.402 × 10⁻⁴ to 0.435 × 10⁻⁴ cm²/s) with increasing concentration from 50 to 150 mg/L. The maximum percentage Cu²⁺ removal (89.56%) and uptake (32.64 mg/g) were found at 3.5 mL/min and 20 cm bed height. In addition to this the Bed Depth Service Time (BDST) model was in good agreement with the experimental data with a high correlation coefficient (>0.995). Furthermore, sorption and desorption studies were also carried out which showed that polysulphone immobilized biomass could be reused for up to six sorption–desorption cycles.     

Production of Fe2O3 from FeSO4·xH2O formed in galvanizing works

FeSO₄·xH₂O is generated in large amounts in galvanizing workshops. It can be reutilized by conversion to Fe₂O₃. In this study, the recovery of Fe₂O₃ from FeSO₄·xH₂O formed in the galvanizing process has been examined. The experimental work was carried out at various temperatures and times in the oxidizing medium. The reaction temperatures and times were selected as 450, 500, 550, 600, 650, 700, 800 and 900°C, and 15, 30, 45, 60, 90 and 120 minutes, respectively. In order to determine the amount of Fe₂O₃, a titrimetric method was applied. The reaction products were characterized by means of IR and XRD techniques.The extent of conversion is low at temperatures below 650°C. Almost all of the iron (II) sulfate in the original sample was converted to iron(III) oxide at 650°C (120 min), 700°C (90 min), 800°C (60 min) and 900°C (45 min).     

Effect of selected and non-selected urban waste compost on the initial growth of corn

Brazil produces approximately 242,000 t of waste per day, 76% of it being dumped outdoors and only 0.9% recycled, including composting, which is an alternative still little known in Brazil. In search of a better destination for residues produced by domestic activities, composting stands as a feasible alternative. Organic compost from waste may be used for various purposes, among which are soil recovery, commercial production, pastures, lawns and reforestry and agriculture. However, the quality of the compost determines the growth and the development of plants. The effect of compost made from urban waste on corn plant (Zea mays L.) growth was investigated. Two types of compost were used: the selected compost (SC), produced from organic waste selectively collected; and the non-selected compost (NSC), taken from a 15-year-old cell from the Canabrava land-fill, located in Salvador, Bahia, Brazil (altitude 51 m, 12°22′–13°08′S, 38°08′–38°47′W). Corn was seeded in polyethylene pots, with soil-compost mixing substrate in the proportion of 0, 15, 30, 45 and 60 t ha⁻¹ equivalent doses. Chemical analyses of the compost and growth properties of the plant like chlorophyll content; height and stem diameter; aerial and radicular dry biomasses, were used to evaluate compost quality. Plants cultivated with SC presented a superior gain, being of 52.5% in stem diameter, 71.1 and 81.2% in root and stem biomasses, respectively. Chlorophyl content alterations were observed in plants from treatments using 30 t compost ha⁻¹ dose onwards. Conventional and multivariate statistical methods were used to evaluate these results. The beneficial action of organic compost in plant growth was confirmed with this research.     

Potential environmental fate of elsinochrome A,a perylenequinone toxin produced in culture by bindweed biocontrol fungus Stagonospora convolvuli LA39

The photosensitizing perylenequinone toxin elsinochrome A (EA) is produced in culture by the bindweed biocontrol fungus Stagonospora convolvuli LA39 where it apparently plays a pathogenicity related role. We investigated the fate of EA with reference to its stability under different temperature and light conditions. EA remained stable when boiled in water at 100^∘C for 2 h. Similarly, exposing EA to 3–27^∘C in the dark for up to 16 weeks did not affect its stability either in dry or in aqueous form. However, results from irradiation experiments indicate that direct photolysis may be a significant degradation pathway for EA in the environment. EA either in dry form or dissolved in water was degraded by different irradiation wavelengths and intensities, with degradation plots fitting a first order rate kinetics. EA degraded faster if exposed in aqueous form, and at higher quantum flux density (μmol s⁻¹ m⁻²). Sunlight was more effective in degrading EA than artificial white light and ultraviolet radiations (UV-A or UV-B). Exposing EA to natural sunlight, particularly, during the intense sunshine (1,420– 1,640 μmol s⁻¹ m⁻²) days of 30 July to 5 August 2004 in Zurich caused the substance to degrade rapidly with half-life under such condition only 14 h. This implies that should EA gets into the environment, particularly on exposed environmental niches, such as on plant surfaces through biocontrol product spray, or released from shed diseased leaves, it may have no chance of accumulating to ‘level of concern’. Furthermore, a toxicity assay using Trichoderma atroviride P1 as biosensor showed that photo-degraded EA was not toxic, indicating that no stable toxic by-products were left.     

An intergrated waste survey and environmental effects of COGIDO, a bleached pulp and paper mill in Vietnam, on the receiving waterbody

An integrated investigation on wastewater characterization and the environmental effects from the COGIDO pulp and paper mill in Bien Hoa Industrial Estate, Vietnam, a chlorine bleached soda integrated pulp and paper mill operating without a chemical recovery system, on the receiving water body was conducted during the rainy and dry seasons in 1993 and 1995. The pollution load from the mill was very high in terms of BOD, COD and SS (COD_m: 58.7 t/d; BOD: 33.3 t/d and SS: 25.1 t/d). The effluent toxicity was determined using four toxicity tests: the green micro-alga, Selenastrum capricornutum, Microtox (marine bacteria: Photobacterium phosphoreum), the duckweed, Lemna aequinoctialis, and fish (silver barb: Puntius gonionotus, and Tilapia: Tilapia nilotica). Selenastrum capricornutum was the most sensitive among the tested organisms. The mill toxicity emission rate (TER) was as high as 338 610 (Selenastrum test). The bleaching-pulp and semi-chemical pulp plants which contributed the largest pollution load to the total COGIDO effluent, therefore, were targeted for abatement measures. Physico-chemical parameters as well as qualitative and quantitative aquatic organism composition for the river water were established. The BOD₅ and COD values exceeded the potable surface water standard by a factor of 2 to 4. The species diversity and abundance of the phytoplankton, zooplankton and zoobenthos were found to be lower (20–40%) than that of unpolluted rivers in Vietnam, whereas pollution-indicator species increased up to four times during the dry season 1995.     

Differential fitness of allelic isozymes in the marine gastropodsLittorina punctata andLittorina neritoides,exposed to the environmental stress of the combined effects of cadmium and mercury pollution

The present study tested the separate and the interactive pollution effects of cadmium and mercury on the electrophoretically detected allelic isozyme frequencies of the enzyme phosphoglucose isomerase for two species of littoral marine gastropods —Littorina punctata andL. neritoides — and the enzyme amino peptidase forL. neritoides. Our results indicate differential survivorship of allelic isozyme genotypes specific for each type of pollutant and for their interaction, as well as trends common to all pollutants. Theoretically the results reflect the adaptive nature of at least some allozymic genotypes in these marine gastropods and seem inconsistent with the neutral theory of allozyme polymorphisms. Practically, the results reinforce earlier conclusions that changes in the frequency of allelic isozymes may be used as a genetic monitor of pollution.     

Water/acid gas interfacial tensions and their impact on acid gas geological storage

Acid gas geological disposal is a promising process to reduce CO₂ atmospheric emissions and an environment-friendly and economic alternative to the transformation of H₂S into sulphur by the Claus process. Acid gas confinement in geological formations is to a large extent controlled by the capillary properties of the water/acid–gas/caprock system, because a significant fraction of the injected gas rises buoyantly and accumulates beneath the caprock. These properties include the water/acid gas interfacial tension (IFT), to which the so-called capillary entry pressure of the gas in the water-saturated caprock is proportional. In this paper we present the first ever systematic water/acid gas IFT measurements carried out by the pendant drop technique under geological storage conditions. We performed IFT measurements for water/H₂S systems over a large range of pressure (up to P = 15 MPa) and temperature (up to T = 120 °C). Water/H₂S IFT decreases with increasing P and levels off at around 9–10 mN/m at high T (≥70 °C) and P (>12 MPa). The latter values are around 30–40% of water/CO₂ IFTs, and around 20% of water/CH₄ IFTs at similar T and P conditions. The IFT between water and a CO₂ + H₂S mixture at T = 77 °C and P > 7.5 MPa is observed to be approximately equal to the molar average IFT of the water/CO₂ and water/H₂S binary mixtures. Thus, when the H₂S content in the stored acid gas increases the capillary entry pressure decreases, together with the maximum height of acid gas column and potential storage capacity of a given geological formation. Hence, considerable attention should be exercised when refilling with a H₂S-rich acid gas a depleted gas reservoir, or a depleted oil reservoir with a gas cap: in the case of hydrocarbon reservoirs that were initially (i.e., at the time of their discovery) close to capillary leakage, acid gas leakage through the caprock will inevitably occur if the refilling pressure approaches the initial reservoir pressure.     

160 h of chemical-looping combustion in a 10 kW reactor system with a NiO-based oxygen carrier

Chemical-looping combustion, CLC, is a technology with inherent separation of the greenhouse gas CO₂. The technique uses an oxygen carrier made up of particulate metal oxide to transfer oxygen from combustion air to fuel. In this work, an oxygen carrier consisting of 60% NiO and 40% NiAl₂O₄ was used in a 10 kW CLC reactor system for 160 h of operation with fuel. The first 3 h of fuel operation excepted, the test series was accomplished with the same batch of oxygen carrier particles. The fuel used in the experiments was natural gas, and a fuel conversion to CO₂ of approximately 99% was accomplished. Combustion conditions were very stable during the test period, except for the operation at sub-stoichiometric conditions. It was shown that the methane fraction in the fuel reactor exit gas was dependent upon the rate of solids circulation, with higher circulation leading to more unconverted methane. The carbon monoxide fraction was found to follow the thermodynamical equilibrium for all investigated fuel reactor temperatures, 660–950 °C. Thermal analysis of the fuel reactor at stable conditions enabled calculation of the particle circulation which was found to be approximately 4 kg/s, MW. The loss of fines, i.e. the amount of elutriated oxygen carrier particles with diameter <45 μm, decreased during the entire test period. After 160 h of operation the fractional loss of fines was 0.00022 h⁻¹, corresponding to a particle life time of 4500 h.     

Effect of oxygenated liquid additives on the urea based SNCR process

An experimental investigation was performed to study the effect of oxygenated liquid additives, H₂O₂, C₂H₅OH, C₂H₄(OH)₂ and C₃H₅(OH)₃ on NO_x removal from flue gases by the selective non-catalytic reduction (SNCR) process using urea as a reducing agent. Experiments were performed with a 150 kW pilot scale reactor in which a simulated flue gas was generated by the combustion of methane operating with 6% excess oxygen in flue gases. The desired levels of initial NO_x (500 ppm) were achieved by doping the fuel gas with ammonia. Experiments were performed throughout the temperature range of interest, i.e. from 800 to 1200 °C for the investigation of the effects of the process additives on the performance of aqueous urea DeNO_x. With H₂O₂ addition a downward shift of 150 °C in the peak reduction temperature from 1130 to 980 °C was observed during the experimentation, however, the peak reduction efficiency was reduced from 81 to 63% when no additive was used. The gradual addition of C₂H₅OH up to a molar ratio of 2.0 further impairs the peak NO_x reduction efficiency by reducing it to 50% but this is accompanied by a downward shift of 180 °C in the peak reduction temperature. Further exploration using C₂H₄(OH)₂ suggested that a 50% reduction could be attained for all the temperatures higher than 940 °C. The use of C₃H₅(OH)₃ as a secondary additive has a significant effect on the peak reduction efficiency that decreased to 40% the reductions were achievable at a much lower temperature of 800 °C showing a downward shift of 330 °C.     

Perceptions of the security and attractiveness of urban parking lots

This study concerns design features of urban parking lots which can increase the perception of such areas as both safe and attractive. College students evaluated the attractiveness and perceived security associated with 180 scenes of parking lots adjacent to commercial and multi-family residential structures in Atlanta and Athens, Georgia, U.S.A. High intergroup correlations (r > 0·90) indicated the reliability of evaluations of both perceived features. Regressions of physical features on perceived security ratings and attractiveness ratings yielded highly predictive models (R² = 0·76 and 0·80, respectively). For both sets of ratings a Maintenance and Design factor accounted for the most variance. Although attractiveness ratings were higher as the total amount of vegetation increased in a scene, security was in general rated higher only when vegetation was well maintained and appeared to be installed as part of a landscape design. Attractiveness was generally higher for multi-family residential scenes than for commercial scenes. Perceived security was higher for frontal views of structures, especially when entrances were proximate to the viewer. Research implications are discussed in terms of the impact of natural features in urban areas for increasing attractiveness and reducing fear of crime.     

Model Computations on Sequestration of Carbon in Managed Forests and Wood Products under Changing Climatic Conditions in Finland

The aim of this study was to assess the effects of forest management on carbon sequestration in forests and wood products by using a gap-type forest model interfaced with a wood product model. The assessment is based on total carbon sequestration, i.e. the amount of carbon left in vegetation, litter, soil organic matter and products when the flows of carbon back to the atmosphere have been subtracted. Thirty mixed-species stands, representing medium fertility sites in southern Finland, were included in each simulation for 300 years under current climatic conditions and predicted conditions of changing climate. The average total balance for the first 100 years was higher in the unmanaged system than in the managed system, but for the second and third 100-year periods the results were clearly opposite. Differences in the total balance between the treatments were larger during the first 100 years than over the whole 300-year period. Under conditions of changing climate, differences in carbon sequestration between management options were more pronounced than under current climatic conditions. Under current climatic conditions with the 100-year time frame, the ratio between the total annual balance and annual gross production was 0·208–0·289. Over the whole 300 years, however, efficiency was much lower, 0·088–0·121. Under changing climatic conditions, efficiency was also lower, 0·182–0·252 and 0·081–0·096, respectively. Different management alternatives clearly produced different amounts of timber for the production process; under conditions of changing climate, timber production was substantially enhanced. However, total carbon storages at the end of the simulation varied less than timber production. In the managed system, the flow back into the atmosphere was largest from litter, 41–51% of the total outflow, the flow from vegetation was 23–28%, from soil organic matter 22–25%, emissions from products 1–7%, and emissions from landfills 0–3%. If emissions due to the use of machinery in timber harvesting and transportation were included, they made up only 0·03–0·33% of the total outflow.     

《大气污染防治行动计划》实施环境效果模拟

本研究利用2010年污染源普查数据和MEIC排放清单建立全国大气污染物高时空分辨率排放清单,在此基础上利用2012年环境统计数据对其进行修订建立2012年全国大气污染物高时空分辨率排放清单;结合《大气污染防治行动计划》(以下简称《计划》)研究工作,测算了《计划》实施后在污染源综合治理、落后产能淘汰、能源结构调整方面对SO2、NOx、颗粒物、VOCs的减排量,同时对污染物新增量进行了预测,建立了《计划》实施后全国大气污染物高时空分辨率排放清单;利用CMAQ空气质量模型模拟分析了《计划》实施的空气质量改善效果。结果表明:《计划》实施后,将可以减少641万吨SO2、859万吨NOx、547万吨颗粒物(不含扬尘污染控制)、627万吨VOCs,全国、京津冀、长三角及珠三角区域PM2.5年均浓度将分别比2012年下降22.08%、33.99%、23.98%、24.04%。如果《计划》要求全部落实,可以实现空气质量改善目标。     

Effect of spent engine oil on the growth parameters and chlorophyll content of <Emphasis Type="Italic">Corchorus olitorius</Emphasis> Linn

The effect of spent engine oil on the height, leaf number, leaf area, stem girth, chlorophyll, and moisture contents of Corchorus olitorius grown on 0, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 2.0%, and 3.0% (v/w oil/soil) oil-contaminated soil was investigated. The engine oil at all concentrations delayed the germination of C. olitorius by 2 days (compared to control) and there was a general significant reduction in all the growth parameters in plants grown on contaminated soil compared to control plants. The highest leaf area of 26.8 cm² was found in the control plant and least was found in the 0.6% soil (0.11 cm²) after 3 weeks while no values were recorded on the 0.8–3.0% engine-oil-contaminated soil after 5 weeks of experiment. The highest chlorophyll content was also found in the control plant (11.5 mg/l). This showed that spent engine oil has an adverse effect on the growth of C. olitorius plant.     

Effect of stocking density and food quality on the growth and fecundity of an epigeic earthworm (<Emphasis Type="Italic">Eisenia fetida</Emphasis>) during vermicomposting

Physico-chemical characteristics of the feed and optimum worm density are important parameters for the efficient working of a vermicomposting system. Overcrowding of worms can affect the efficiency of a vermicomposting system even if all other parameters have been optimized. This article reports the effect of stocking density and feed quality on the growth and fecundity of Eisenia fetida under laboratory conditions. The feed mixtures contained cow dung and textile mill wastewater sludge in different ratios. Three feed mixtures and five stocking rates (1, 2, 4, 8, and 12) were tested for 12 weeks. The results showed that E. fetida growth rate was faster at higher stocking densities; however, biomass gain per worm was faster at lower stocking densities. Sexual maturity was attained earlier at higher stocking densities. Growth rate was highest in 100% cow dung at all the stocking densities when compared to textile mill wastewater sludge containing feed mixtures. A worm population of 27–53 worms per kg of feed was found to be the most favorable stocking density.     

Methane fermentation of dung from litter-free reared domestic animals — an optimisation study

Data on the quantity (27 453 tons from litter-free reared animals in Bulgaria, only) and the chemical and energy characteristics of dung produced in intensive management farms for domestic animals suggests that technologies combining biogenic elements recycling with energy utilistation and dung decontamination are expedient to be applied on these types of farms. To this effect a fermenter was designed and a mathematical model (a Chen-Hashimoto model based computer programme) was applied, as a result of which the optimum methane fermentation parameters were determined. The technological methane output (Y_v) — indicator of biogas production efficiency (output/dm³ fermentor volume) showed an optimum at temperature 55°C and period of exchange 6 days. The methane output per unit mineralised organic matter in the substrate (B) — assumed as an indicator of ecological efficiency (maximum organic matter degradation) exhibited an optimum at 33°C for 15 days period of exchange.     

香港吐露港地区河流水质管理效果研究

为探讨香港水质管理的措施及效果,本文对香港吐露港地区5条河流10个监测点1985—2014年的地表水质数据进行分析,观察水体整治管理前后污染物浓度的变化。结果表明:10个监测点的氨氮、BOD_5、COD和TP的浓度均逐年下降,上下游共同努力,使各项污染物得到很大程度的削减,并且治理前后的浓度存在明显统计学差异(p0.05),且治理之后各项污染物年均浓度趋于平稳,达到标准以内。由此可以看出,香港地区水质管理效果的显著与其所实施的《水污染管制条例》、禽畜饲养禁制区设立与吐露港及牛尾海污水收集整体计划密不可分。随着国务院颁布的《水污染防治行动计划》的施行,香港吐露港地区治理的措施可为我国现阶段黑臭水体整治工作所借鉴。     

Diversity of Soil Nematodes in Areas Polluted with Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAHs) in Lanzhou,China

This study investigated the soil nematode community structure along the Yellow River in the Lanzhou area of China, and analyzed the impact of heavy metals (Cd, Pb, Cr, Cu, and Zn) and polycyclic aromatic hydrocarbons (PAHs) on the nematode community. Soil samples from five locations (named A–E), which were chosen for soil analysis, showed significant differences in their heavy metal content (p < 0.01), as well as in the variety of nematodes (up to 41 genera) and families (up to 20) that were present. The different samples also differed significantly in the total PAH content (p < 0.05), as well as the six types of PAH present. Sites A–C showed the most severe contamination with heavy metals and PAHs; these sites had the lowest abundance of fungivores and omnivore/predators, but the proportion of bacteriovores was the highest (p < 0.05). Site E, in contrast, showed only minor pollution with heavy metals and PAHs, and it contained the highest abundance of plant parasites (p < 0.05). Several nematode ecological indicators were found to correlate with concentration of soil pollutants at all the sites tested: the maturity index (MI, in addition to plant parasites), plant parasite index (PPI), ΣMI (including all the soil nematodes), Shannon-Wiener diversity index (H′′), and Wasilewska index (WI). Disturbance to the soil environment was more severe when MI, ΣMI, and H′ values were lower. The results of the study show that the abundance and structure of the soil nematode communities in the sampling locations were strongly influenced by levels of heavy metals and PAHs in the soil. They also show that the diversity index H′ and the maturity index can be valuable tools for assessing the impact of pollutants on nematodes.     

Forest management policies and elk summer carrying capacity in theAbies amabilis forest,western Washington

Effects of different forest management policies on long-term vegetation development are incorporated into a computer simulation of a western Washington watershed. The response of a Rocky Mountain elk(Cervus canadensis nelsoni) population to these vegetation changes is simulated using information on their differential use of vegetation types. Simulations include: 1) a cessation of timber harvesting leading to an immediate decline in elk members resulting from a reduction in summer habitats; 2) a stable elk population, similar to the present one, resulting from a constant timber harvesting rate, and 3) initial increases in herd size, followed within 50 years by a sharp decrease, resulting from cutting all old growth timber within the next decade and then a cessation of timber harvestings.     

Aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing in Guangzhou during the 2006 Pearl River Delta campaign

Optical and chemical aerosol measurements were obtained from 2 to 31 July 2006 at an urban site in the metropolitan area of Guangzhou (China) as part of the Program of Regional Integrated Experiment of Air Quality over Pearl River Delta (PRIDE-PRD2006) to investigate aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing. During the PRIDE-PRD2006 campaign, the average contributions of ammonium sulfate, organic mass by carbon (OMC), elemental carbon (EC), and sea salt (SS) to total PM_2.5 mass were measured to be 36.5%, 5.7%, 27.1%, 7.8%, and 3.7%, respectively. Compared with the clean marine period, (NH₄)₂SO₄, NH₄NO₃, and OMC were all greatly enhanced (by up to 430%) during local haze periods via the accumulation of a secondary aerosol component. The OMC dominance increased when high levels of biomass burning influenced the measurement site while (NH₄)₂SO₄ and OMC did when both biomass burning and industrial emissions influenced it. The effect of aerosol water content on the total light-extinction coefficient was estimated to be 34.2%, of which 25.8% was due to aerosol water in (NH₄)₂SO₄, 5.1% that in NH₄NO₃, and 3.3% that in SS. The average mass-scattering efficiency (MSE) of PM₁₀ particles was determined to be 2.2 ± 0.6 and 4.6 ± 1.7 m² g⁻¹ under dry (RH < 40%) and ambient conditions, respectively. The average single-scattering albedo (SSA) was 0.80 ± 0.08 and 0.90 ± 0.04 under dry and ambient conditions, respectively. Not only are the extinction and scattering coefficients greatly enhanced by aerosol water content, but MSE and SSA are also highly sensitive. It can be concluded that sulfate and carbonaceous aerosol, as well as aerosol water content, play important roles in the processes that determine visibility impairment and radiative forcing in the ambient atmosphere of the Guangzhou urban area.     

Perceived Conflicts Between Pastoralism and Conservation of the Kiang Equus kiang in the Ladakh Trans-Himalaya, India

An emerging conflict with Trans-Himalayan pastoral communities in Ladakh’s Changthang Plateau threatens the conservation prospects of the kiang (Equus kiang) in India. It is locally believed that Changthang’s rangelands are overstocked with kiang, resulting in forage competition with livestock. Here, we provide a review and preliminary data on the causes of this conflict. Erosion of people’s tolerance of the kiang can be attributed to factors such as the loss of traditional pastures during an Indo-Chinese war fought in 1962, immigration of refugees from Tibet, doubling of the livestock population in about 20 years, and increasing commercialization of cashmere (pashmina) production. The perception of kiang overstocking appears misplaced, because our range-wide density estimate of 0.24 kiang km⁻² (± 0.44, 95% CL) is comparable to kiang densities reported from Tibet. A catastrophic decline during the war and subsequent recovery of the kiang population apparently led to the overstocking perception in Ladakh. In the Hanle Valley, an important area for the kiang, its density was higher (0.56 km⁻²) although even here, we estimated the total forage consumed by kiang to be only 3–4% compared to 96–97% consumed by the large livestock population (78 km⁻²). Our analysis nevertheless suggests that at a localized scale, some herders do face serious forage competition from kiang in key areas such as moist sedge meadows, and thus management strategies also need to be devised at this scale. In-depth socioeconomic surveys are needed to understand the full extent of the conflicts, and herder-centered participatory resolution needs to be facilitated to ensure that a sustainable solution for livelihoods and kiang conservation is achieved.