Mining Pollution Research Articles

Evaluation of coal mine pollution abatement benefit based on analytic hierarchy process

Due to the high energy consumption of China’s industrial structure, this has led to serious environmental pollution; in order to improve the efficiency of coal mine pollution reduction, the application of the basic principle of analytic hierarchy process (AHP) was used to select the evaluation index of coal mine pollution reduction, coal mine pollution reduction project, environment benefit evaluation, and target layer analysis. This paper takes the benefit composition and characteristics of coal mine pollution emission reduction project as the entry point, and the actual situation of coal mine pollution emission reduction as the basis; constructs the comprehensive evaluation model of technical and environment benefits of coal mine pollution emission reduction project; and establishes the corresponding comprehensive evaluation system. Through the case study of a mining area, the scientificity, practicality, and feasibility of the index system design are tested.

The Industrial Pollution History Inferred by Stable Pb Isotope in the Chronological Sedimentary Record of a Plateau Lake, Yunnan Province, Southwestern of China

Zhang, Y.; Chang, F.Q.; Duan, L.Z.; Wu, H., Zhang, H.C., 2020. The industrial pollution history inferred by stable Pb isotope in the chronological sedimentary record of a plateau lake, Yunnan Province, Southwestern of China. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 641-647. Coconut Creek (Florida), ISSN 0749-0208.Lake Yangzong, a plateau deep water lake, located in the in Yunnan Province where was the one of the most industrialized regions in China, was suffered seriously mining pollution threat in recent decades. In the present research, based on the 210Pb and 137Cs methods, the chronological sequence of the sediment record collected from the lake basin was established. Combined with the stable isotopic compositions, Pb content and geochemical enrichment index (Igeo), the background of industrial activities and anthropogenic lead (Pb) pollution history were investigated. These results revealed that pollution history could divided into four stages. The contribution of Pb was primarily affected by regional emissions since the open reforming period, and local metal production industries was more involved in the late 1990s. Furthermore, the regional pollution pathways of anthropogenic Pb were mainly affected by atmospheric precipitation and transportation, which were predominately related to mining consumption and smelting industry.

Fecal Pollution Drives Antibiotic Resistance and Class 1 Integron Abundance in Aquatic Environments of the Bolivian Andes Impacted by Mining and Wastewater.

An increased abundance of antibiotic resistance genes (ARGs) in aquatic environments has been linked to environmental pollution. Mining polluted sites with high concentration of metals could favor the in situ coselection of ARGs, whereas wastewater discharges release fecal antibiotic resistant bacteria in the environment. To study the effect of human fecal contamination and mining pollution, water and sediment samples affected by mining activities and sewage discharges were collected from three lakes in Bolivia, the pristine Andean lake Pata Khota, the Milluni Chico lake directly impacted by acid mine drainage, and the Uru-Uru lake located close to Oruro city and highly polluted by mining activities and human wastewater discharges. Physicochemical parameters, including metal composition, were analyzed in water and sediment samples. ARGs were screened for and verified by quantitative polymerase chain reaction (PCR) together with the mobile element class 1 integron (intl1), as well as crAssphage, a marker of human fecal pollution. The gene intl1 was positively correlated with sul1, sul2, tetA, and blaOXA-2. CrAssphage was only detected in the Uru-Uru lake, and its tributaries and significantly higher abundance of ARGs were found in these sites. Multivariate analysis showed that crAssphage abundance, electrical conductivity, and pH were positively correlated with higher levels of intl1 and ARGs. Taken together, our results suggest that fecal pollution is the major driver of higher levels of ARGs and intl1 in environments contaminated by wastewater and mining activities.

Generating and Mapping Amazonian Urban Regions Using a Geospatial Approach

(1) background: Urban representations of the Amazon are urgently needed in order to better understand the complexity of urban processes in this area of the World. So far, limited work that represents Amazonian urban regions has been carried out. (2) methods: Our study area is the Ecuadorian Amazon. We performed a K-means algorithm using six urban indicators: Urban fractal dimension, number of paved streets, urban radiant intensity (luminosity), and distances to the closest new deforested areas, to oil pollution sources, and to mining pollution sources. We also carried out fieldwork to qualitatively validate our geospatial and statistical analyses. (3) results: We generated six Amazonian urban regions representing different urban configurations and processes of major cities, small cities, and emerging urban zones. The Amazonian urban regions generated represent the urban systems of the Ecuadorian Amazon at a general scale, and correspond to the urban realities at a local scale. (4) conclusions: An Amazonian urban region is understood as a set of urban zones that are dispersed and share common urban characteristics such a similar distance to oil pollution sources or similar urban radiant intensity. Our regionalization model represents the complexity of the Amazonian urban systems, and the applied methodology could be transferred to other Amazonian countries.

Preparation and performance evaluation of environment-friendly biological dust suppressant

Enzyme-induced carbonate precipitation (EICP) is an economical and eco-friendly technology. The purpose of this study is to evaluate EICP technology for the control of coal dust pollution in open-pit coal mines. A biological dust suppressant was prepared by using urease extracted from soybean. The optimal proportion of biological dust suppressant was determined and the dust consolidation effect of biological dust suppressant was evaluated. The results show that when the volume ratio of urease and CaCl2-urea solution is 1: 3 and the concentration of CaCl2-urea solution is 0.6 mol/L, the precipitation ratio (PR) (83.83%) in coal dust is the highest. Moreover, the mineralization product is calcite-type CaCO3. In the wind erosion-resistance test, when the angle between the air flow and the sample is 0° and the concentration of CaCl2-urea is 0.6 mol/L, the weight loss of coal dust is 2.56%. The corrosive and toxicological properties of biological dust suppressant show that it is non-toxic, less corrosive and weakly alkaline (pH = 7.70). The above results indicate that EICP is a promising coal dust control technology.

Global Desert Areas Vs Local Mining Areas from Maramure? County (Romania)

Almost a third of the Earth's surface is occupied by vast stretches of stone and sand, having a torrid climate or, on the contrary, extremely frigid. As such, the regions considered to fall into the category of deserts, which can be hot and arid, semi-arid, coastal, or cold, are of interest for the present study. In the same context, at the level of the Maramure? County surface, a major place is occupied by the areas that have served mining activities, and which, at first glance, have similarities with the specific landscapes of deserts. Starting from the aforementioned, through the present work, we intend to underline, in the form of a comparative study, the main common elements that exist between the naturally formed (globally) and anthropic (locally) deserts, for those the latter considering the areas of Maramures County, affected by the specific mining pollution.

Histological Description and Histopathology in Polypedilum sp. (Diptera: Chironomidae): A Potential Biomarker for the Impact of Mining on Tributaries

Abstract The Neotropical region has a wide aquatic biodiversity, which is affected by anthropogenic activities. Mining has caused a negative impact on these ecosystems, directly affecting benthic communities. Aquatic macroinvertebrates are effective bioindicators of water quality, especially Chironomidae larvae, since these show high species richness, abundance, and sensitivity to human activities. The genus Polypedilum is among the most representative of the family Chironomidae. Research on these species is focused on their abundance and dominance in water bodies. In addition, several studies have addressed alterations in the external morphology of some Chironomidae due to mining pollution (heavy metals). However, little is known about the effects of mining on the internal morphology of these species. This study provides the first histological description of different systems and organs of Polypedilum sp. larvae. Furthermore, we report histopathological alterations in larvae collected from two tributaries affected by mining, namely Toldafría and La Elvira streams located in the municipalities of Villamaría and Manizales (Caldas – Colombia). Our findings show target organs of mining pollution in a species of Polypedilum, which represent potential early-warning histopathological biomarkers with relevant implications for water quality monitoring.

Effect of Cropping System and Nitrogen on Maize and Soy Bean Yields in Western Kenya

Inherent low soil fertility in the highly weathered and degraded soils largely accounts for low and unsustainable crop yields in most African countries (Okalebo et al., 2006; Sanchez et. al., 1997). Productivity of maize and soybeans in Kenya, particularly in the western region is generally low. The high costs of inorganic fertilizers and the possibility of decreasing soil productivity in due to soil mining and environmental pollution demands a reassement of their use, vis-a-vis, other alternative technologies. The objective of this study was to assess the effect of selected cropping systems, N fertilizer and manure on maize and soy bean crop yields in western Kenya (Bungoma, Vihiga, and Teso). The experiment was a split plot design arranged and laid down in a randomized complete block design (RCBD) with three replications. Cropping systems (mono cropping, MBILI and conventional) were the main factor while fertility interventions (FYM and CAN) were the treatments. The cropping systems consisted of conventional (Maize and soy beans were planted as intercrop in 37.5 cm alternating rows), MBILI (Managing Beneficial Interactions in Legume Intercrops), maize and soybean monocrop. Five fertilizer treatments were used: calcium ammonium nitrate and farm yard manure, both applied at the rate of 30 kg N ha-1 and 75 kg N ha-1, respectively, and absolute control that had no added treatment. Field experiments were planted during two cropping seasons of short rains season (August to December 2011) and one long rains season (April to August 2012) Generally, maize yields were found to be significantly higher in both the mono cropping system (mean yield: 2.00 t/ha) and MBILI system (mean yield: 1.77 t/ha) compared to conventional farming (mean yield: 1.27 t/ha). Soybean yields were found, overall, to be significantly higher in the mono cropping system (mean: 1.00t/ha) compared to both MBILI (mean: 0.75 t ha-1) and conventional system (mean: 0.59 t ha-1). For both maize and soy bean grain, application of CAN75N and planting with FYM75N were found to significantly increase yields, compared to either top dressing with CAN30N or planting with FYM30N. CAN generally produced higher yields with monocrop system whereas MBILI system did better when FYM is used, suggesting that an optimal system could consist of MBILI with organic fertilizers. The mean Land Equivalent Ratio (LER) values were always greater than 1.0 for intercropping and I.0 for mono cropping system. Manure was found to produce similar yields as those in fertilizer applications. This study recommends MBILI system and organic manure as a beneficial way of growing maize and soy beans

Effects of the watershed on the seasonal variation of the surface water quality of a post-restoration coastal wetland: The case of the Nador lagoon (Mediterranean sea, Morocco)

The Nador lagoon is a coastal wetland which is subject to both the watershed pressures and land runoffs coming from domestic, agricultural, industrial and mining pollution. In 2017, 19 stations encompassing the entire lagoon and pollution sources, including 13 at the lagoon level and 6 at the watershed level, were sampled during wet and dry seasons. Descriptive and multivariate statistical analyses were used to assess its environmental status through physio-chemical, nutrients and trace metals parameters. The results show that seasonal variations significantly affected the concentrations of Fe, Cu, Cr, and Cd in the lagoon. The highest mean concentrations were recorded for Mn, Zn, Cr and Pb during the wet season and for Fe, Cu, Ni and Cd during the dry season. The average concentrations of Pb, Cd, Cr, Zn and Mn in the lagoon were lower than the USEPA 2016 standards on saltwater aquatic life preservation while the average concentrations of Ni and Cu are higher. In order to preserve this wetland, the implementation of an environmental management plan is required focusing on the rehabilitation of the iron mining area, the extension of the sewerage network, the control of agricultural effluents and the upgrading of industrial pollution controls.

Lead contamination from gold mining in Yellowknife Bay (Northwest Territories), reconstructed using stable lead isotopes

The contributions of contaminant sources are difficult to resolve in the sediment record using concentration gradients and flux reconstruction alone. In this study, we demonstrate that source partitioning using lead isotopes provide complementary and unique information to concentration gradients to evaluate point-source releases, transport, and recovery of metal mining pollution in the environment. We analyzed eight sediment cores, collected within 24 km of two gold mines, for Pb stable isotopes, Pb concentration, and sediment chronology. Stable Pb isotope ratios (206Pb/207Pb, 208Pb/204Pb) of mining ore were different from those of background (pre-disturbance) sediment, allowing the use of a quantitative mixing model. As previously reported for some Arctic lakes, Pb isotope ratios indicated negligible aerosol inputs to sediment from regional or long-range pollution sources, possibly related to low annual precipitation. Maximum recorded Pb flux at each site reached up to 63 mg m−2 yr−1 in the period corresponding to early years of mining when pollution mitigation measures were at a minimum (1950s–1960s). The maximum contribution of mining-derived Pb to these fluxes declined with distance from the mines from 92 ± 8% to 8 ± 4% at the farthest site. Mining-derived Pb was still present at the sediment surface within 9 km of Giant Mine more than ten years after mine closure (5–26 km, 95% confidence interval) and model estimates suggest it could be present for another ∼50–100 years. These results highlight the persistence of Pb pollution in freshwater sediment and the usefulness of Pb stable isotopes to quantify spatial and temporal trends of contamination from mining pollution, particularly as concentrations approach background.

Tracing geochemical pollutants in stream water and soil from mining activity in an alpine catchment.

This research developed a method of tracing major water chemical parameters (WCP) and soil heavy metals (HM) to identify the processes of mining pollution in topographically complex landscapes. Ninety-nine spatially distributed water samples were collected to characterise the hydrochemical characteristics of an alpine river in north-west China. Sixty river WCP and fifty-six soil HM samples from areas near mining sites were then used to analyse the mining pollution process. Geographical and mining activity characteristics were derived from topographic and mine site information. The occurrence of sulphates (SO42-) and nitrates (NO3-) in river water were highly correlated (up to 0.70), providing strong evidence of pollution from nearby mining activities. Levels of arsenic and cadmium were high in first and fifth order streams, where mining activities were most concentrated. The modelling results showed that geographical patterns and mining activity account for predicting HM distribution, and WCP can be reasonable predictors to trace soil mining pollution. This research can help improve the accuracy of predicting the mining pollution process.

There is a Monster Under the Ground: Commemorating the History of Arsenic Contamination at Giant Mine as a Warning to Future Generations

This paper analyzes a community-based project to communicate toxic dangers to future generations at Giant Mine, an abandoned gold mine near Yellowknife. Since 2013, the authors have worked with community groups, government, the Yellowknives Dene First Nation to develop a strategy for communicating the arsenic hazards at Giant Mine to future generations. Our experience suggests that any communication strategy must commemorate the multiple ways different constituents have known the mine. We also argue that any program to commemorate hazards for future generations can be a useful tool to address painful memories of historical environmental injustices associated with mine pollution.

Multidimensional pollution and potential ecological and health risk assessments of radionuclides and metals in the surface soils of a uranium mine in East China

Pollution from long-lived radionuclides coupled with metals and metalloids (MMs) in uranium mines is globally considered a primary environmental concern. However, research on this topic has been limited to uncovering the ecological and human health risks of this combined pollution in uranium mines. A total of 120 surface soil samples were collected from 40 sampling sites at a uranium mine in East China. The health hazards of the natural radionuclides were evaluated according to their absorbed dose rate, radium equivalent, hazard indices, annual effective dose equivalent, and excess lifetime cancer risk. Moreover, the contamination statuses and potential ecological and health risks to children and adults through different MM exposure routes were revealed using the geo-accumulation index (Igeo), contamination factor (Cf), pollution loading index (PLI), potential ecological risk index (RI), and US EPA health risk assessment models. The interactions between potential ecological and health risks were shown by using the regression fitting method, and the Pearson correlations between the radionuclides and MM were also calculated. Results showed that only the average activity concentration of the radionuclide 40K was much higher than the global average, but the health hazard and radiological parameters were within acceptable levels. The average Cd content was 1.6 times the local background value and slightly less than that of grade I in the Chinese soil quality guidelines, which posed potential ecological risks to the study area, although other MMs were present at levels lower than both of the reference values. The Igeo, Cf, PLI, and RI results suggested that the contamination around the uranium facilities was more serious than at other sampling sites. Health risk assessments showed that ingestion was the primary route for the metals to enter the human body and threaten human health. The carcinogenic risk from Ni and As to children and adults was the primary health concern in the study area. Moreover, the children were potentially under higher carcinogenic risk than the adults. The correlation analyses between potential ecological and health risks showed that the compatibility between the RI and HIA, HIC, or CRC, respectively, was acceptable when applied in the study area. Strong positive correlations were also found between the 238U, 232Th, 226Ra, 40K, 137Cs, Cu, As, and Ni. Pollution from long-lived radionuclides and their associated MMs has posed potential ecological risks to the ecosystem and caused human carcinogenic risk in the study area.

Green sea urchins (Strongylocentrotus droebachiensis) as potential biomonitors of metal pollution near a former lead-zinc mine in West Greenland.

In this study, metal accumulation in green sea urchins (Strongylocentrotus droebachiensis) was investigated near the former Black Angel lead-zinc mine in Maarmorilik, West Greenland. Sea urchins (n = 9-11; 31-59 mm in diameter) were collected from three stations located at < 1 km, 5 km, and 12 km (reference site) away from the former mine site, respectively. After collection, tissue of the sea urchins was divided into gonads and remaining soft parts (viscera) before subjected to chemical analyses. Focus was on eight elements found in elevated concentrations in the mine waste (iron, copper, zinc, arsenic, silver, cadmium, mercury and lead). Sea urchins at the mine site contained significantly more copper, mercury and lead compared with the reference site for both the gonads and viscera, while the latter also contained significantly more iron, zinc and silver. Arsenic and cadmium were not significantly elevated in sea urchins at the mine site. Most elements were found in higher concentrations in the viscera compared with the gonads. For comprehensive monitoring of metal pollution at mine sites, a diverse selection of monitoring organisms is necessary. The study shows that green sea urchins accumulate selected metals and can be used as a monitoring organism for mining pollution, at least for iron, copper, zinc, silver, mercury and lead. However, the results also show that green sea urchins are less likely to reflect small environmental changes in loading of most metals (except iron, copper and silver) and for arsenic compared to suspension feeders such as blue mussels.

Estimating PM10 Concentration from Drilling Operations in Open-Pit Mines Using an Assembly of SVR and PSO

Dust is one of the components causing heavy environmental pollution in open-pit mines, especially PM10. Some pathologies related to the lung, respiratory system, and occupational diseases have been identified due to the effects of PM10 in open-pit mines. Therefore, the prediction and control of PM10 concentration in the production process are necessary for environmental and health protection. In this study, PM10 concentration from drilling operations in the Coc Sau open-pit coal mine (Vietnam) was investigated and considered through a database including 245 datasets collected. A novel hybrid artificial intelligence model was developed based on support vector regression (SVR) and a swarm optimization algorithm (i.e., particle swarm optimization (PSO)), namely PSO-SVR, for estimating PM10 concentration from drilling operations at the mine. Polynomial (P), radial basis function (RBF), and linear (L) kernel functions were considered and applied to the development of the PSO-SVR models in the present study, abbreviated as PSO-SVR-P, PSO-SVR-RBF, and PSO-SVR-L. Also, three benchmark artificial intelligence techniques, such as k-nearest neighbors (KNN), random forest (RF), and classification and regression trees (CART), were applied and developed for estimating PM10 concentration and then compared with the PSO-SVR models. Root-mean-squared error (RMSE) and determination coefficient (R2) were used as the statistical criteria for evaluating the performance of the developed models. The results exhibited that the PSO algorithm had an essential role in the optimization of the hyper-parameters of the SVR models. The PSO-SVR models (i.e., PSO-SVR-L, PSO-SVR-P, and PSO-SVR-RBF) had higher performance levels than the other models (i.e., RF, CART, and KNN) with an RMSE of 0.040, 0.042, and 0.043; and R2 of 0.954, 0.948, and 0.946; for the PSO-SVR-L, PSO-SVR-P, and PSO-SVR-RBF models, respectively. Of these PSO-SVR models, the PSO-SVR-L model was the most dominant model with an RMSE of 0.040 and R2 of 0.954. The remaining three benchmark models (i.e., RF, CART, and KNN) yielded a more unsatisfactory performance with an RMSE of 0.060, 0.052, and 0.067; and R2 of 0.894, 0.924, and 0.867, for the RF, CART, and KNN models, respectively. Furthermore, the findings of this study demonstrated that the density of rock mass, moisture content, and the penetration rate of the drill were essential parameters on the PM10 concentration caused by drilling operations in open-pit mines.

Multiple environmental variables influence diatom assemblages across an arsenic gradient in 33 subarctic lakes near abandoned gold mines

We examined surface sediment diatom assemblages from 33 subarctic lakes around the historic gold mines in Yellowknife, Northwest Territories (Canada), where lake-water As concentrations ([As]) still range between 1.5 and 2,780 µg/l, even though the roasting of the arsenopyrite-bearing gold ores ceased in 1999. Water chemistry variables related to gold mining pollution (arsenic, antimony, and sulfate) declined with increasing distance from the mines. The diatom assemblages varied substantially in species composition across our study lakes with the planktonic Discostella stelligera/pseudostelligera complex dominating in deep lakes where [As] were less than 5 µg/l. However, in lakes that exceeded the guideline for the protection of aquatic life ([As] > 5 µg/l), opportunistic benthic diatoms (small fragilarioid taxa and Achnanthidium minutissimum) were generally present in higher abundances. The subtle differences in diatom species richness and diversity among lakes with varying [As] suggest these indices may not be affected strongly by long-term arsenic pollution. Furthermore, canonical correspondence analysis of the diatom assemblage and environmental data indicated that nutrient and ionic compounds explained most of the variation in the assemblages, while mining-related variables played a limited role. Our results indicate that multiple limnological variables (nutrients, ions, and contaminants) and subarctic climatic conditions are important factors shaping the diatom assemblage composition in lakes impacted by mining activities and land-use changes near Yellowknife.

Experimental and numerical study on heavy metal contaminant migration and retention behavior of engineered barrier in tailings pond

Heavy metal pollution is a serious environmental problem globally, particularly in mines and tailings ponds. In this study, based on laboratory and field tests, the migration of heavy metal contaminants in a tailings pond and the retention behavior of a compacted bentonite engineered barrier system on the heavy metal contaminants were analyzed by a numerical simulation. The results demonstrate that the hydraulic conductivity of compacted bentonite is lower than that of the tailings from the laboratory tests. The hydraulic conductivity of the tailings sand decreased with an increase in the dry density and increased with an increase in the concentration of the chemical solution, which could be attributed to the large amounts of fine-grained soil contained in the tailings, according to the grain size distribution test. The hydraulic conductivity of the tailings from the engineering geological survey was between 2.0 × 10−6 and 9.0 × 10−5 m/s, and followed the order: tail coarse sand ＞ tail silty sand ＞ tail medium sand ＞ tail fine silt. The numerical simulation of the seepage could satisfactorily describe the actual working condition of the tailings dam. With the groundwater seepage, the migration range of the heavy metal contaminant in the researched tailings pond reached a maximum of 45 m for 5 years. The retention efficiencies of the 0.2 m engineered barrier against the heavy metal contaminant for 15 and 30 years were 45.4% and 57.2%, respectively. Moreover, the retention efficiency would exceed 87% when the engineered barrier thickness is increased to 0.5 m. The results of model validation show that the calculated results are in good agreement with the measured ones. These findings can provide effective ideas for the prevention and control of environmental pollution in mines and tailings ponds.

International Ties at Peripheral Sites: Co-producing Social Processes and Scientific Knowledge in Latin America

ABSTRACTIn recent decades, scientific knowledge has been increasingly expected to contribute to the resolution of public and controversial issues in Latin America. However, in peripheral sites of knowledge and economic production, the dynamics of both science and society have been complicated by tensions between the demands of local stakeholders and the ties with the global centers of technical and scientific expertise. First, local public issues are often addressed in merely discursive ways, rather than effectively, in research and expert advice; second, local scientific elites often establish links with experts and the global centers of science in order to legitimate their stance against competing approaches. An analysis of four case studies (neglected diseases, mining pollution, wildlife conservation and migration studies) involving the production of scientific knowledge intended to address public issues in Latin America reveals, first, that material and symbolic asymmetries determine the outcomes of these engagements and, second, that international ties with peripheral sites affect the cognitive definition of the issues at stake and the range of public interventions devised to address them. Yet, in these four case studies, the key actors that mediate links between local stakeholders and international counterparts – or, ‘drivers’ – mobilize the bodies of knowledge that, ultimately, shape the cognitive and political contours of the social issues at stake.

Seasonal variation of arsenic and antimony in surface waters of small subarctic lakes impacted by legacy mining pollution near Yellowknife, NT, Canada

The seasonal variation in lake water arsenic (As) and antimony (Sb) concentrations was assessed in four small (<1.5km2) subarctic lakes impacted by As and Sb emissions from legacy mining activities near Yellowknife, Northwest Territories, Canada. Substantial variation in As concentrations were measured over the two-year period of study in all but the deepest lake (maximum depth 6.9m), including a four-fold difference in As in the shallowest lake ([As]: 172–846μgL−1; maximum depth 0.8m). Arsenic concentrations were enriched following ice cover development in the three shallowest lakes (50–110%) through a combination of physical and biogeochemical processes. Early winter increases in As were associated with the exclusion of solutes from the developing ice-cover; and large increases in As were measured once oxygen conditions were depleted to the point of anoxia by mid-winter. The onset of anoxic conditions within the water column was associated with large increases in the concentration of redox sensitive elements in lake waters (As, iron [Fe], and manganese [Mn]), suggesting coupling of As mobility with Fe and Mn cycling. In contrast, there was little difference in Sb concentrations under ice suggesting that Sb mobility was controlled by factors other than Fe and Mn associated redox processes. A survey of 30 lakes in the region during fall (open-water) and late-winter (under-ice) revealed large seasonal differences in surface water As were more common in lakes with a maximum depth <4m. This threshold highlights the importance of winter conditions and links between physical lake properties and biogeochemical processes in the chemical recovery of As-impacted subarctic landscapes. The findings indicate annual remobilization of As from contaminated lake sediments may be inhibiting recovery in small shallow lakes that undergo seasonal transitions in redox state.

Spatiotemporal variation in primary nutrients amassing in peninsular river sediment: India

Damodar is an important river of the industrial state Jharkhand, India. It menders through various coal mining regions is now under serious threats due to industrial and sewage discharge which is rich in TOC, available nitrogen, phosphorus and potassium (primary nutrient plants). Hence, present research work was formulated with the hypothesis of “river sediment possess high concentration of primary nutrients which can be used in mine site reclamation”. In this regard, spatiotemporal and seasonal variations in concentration of these nutrients were studied to know its sources. Nutrient index of the sediment was assessed to compare its fertility with soil for its utilization in mine site reclamation and pollution control of the river. Study area has momentous spatial variation; Garga river (site 12) carry sewage and effluent from Bokaro steel city having maximum concentration of TOC, available N, and P, while available K was maximum at Chandrapura thermal power plant (site 9). Substantial seasonal and temporal disparity in nutrient concentration was also found. In 2014, TOC (0.82 and 0.5)%, available N (12.3 mg/kg and 7.9 mg/kg), P (11.3 mg/kg and 6.2 mg/kg), and available K was (218 mg/kg and 201.7 mg/kg), respectively, in pre- and post-monsoon. These amplified to 39% for TOC, 19–29% for nitrogen, more than 35% for phosphorus and 2.9–3.9% for K by 2016. The nutrient index was medium for TOC and pH except low in 2014 post-monsoon. Nutrient index for nitrogen was low while high for phosphorus and potassium during the study.