Input Of Pollutants Research Articles

ANALISIS DAYA TAMPUNG BEBAN PENCEMARAN SUNGAI SIAK BAGIAN HULU

This research was conducted in April 2018 and took place in the upper reaches of batang siak river, on the Sungai Tekuana, Tekuana Pendek, and Jamu Bualo. The purpose of this research is to evaluate the waters of the upstream part in Siak River according to its status and quality based on environmental quality standards, calculate the load capacity of the upstream part of the Siak River pollutants, and determine the pollutant input from the tributaries leading to the upstream body of the Siak River. Based on the results of research BOD parameters have passed the upstream capacity of the Siak river. For sampling point 2 about -1750.43 mg / sec, sampling point 5 about -4474.31 mg / sec, and tributary point 1 about -0.42355 mg / sec, while river storage data for other parameters such as COD and TSS are still good.

Agricultural and urban delivered nitrate pollution input to Mediterranean temporary freshwaters

Nitrate dual stable isotopes (δ15NNO3 and δ18ONO3) have proven to be a powerful technique to trace nitrate sources and transformations in freshwater systems worldwide. However, most studies have focused on perennial systems, and less is known about intermittent ones. The impacts of intensive agricultural practices and wastewaters in Doñana (SW Spain), an iconic Mediterranean temporary wetland protected as a UNESCO World Heritage Site, were quantified using stable isotope mixing models in a Bayesian framework under different denitrification scenarios. We aimed to identify the main nitrate sources and transformation processes in surface waters of interconnected temporary streams, ponds and marshes, and link them with the main human pressures in the watershed (e.g. intensive fruticulture, urban wastewaters). We measured nitrate (NO3−) concentrations and stable isotopes (δ15NNO3 and δ18ONO3) in water samples collected during different periods over two years (2015–2016). Most sites showed coupled increases of nitrate isotopic values (δ15NNO3 and δ18ONO3), which were higher than reference values of any possible sources (e.g. synthetic/organic fertilizers and wastewaters), indicating fractionations typical of denitrification processes. The main nitrate sources to the watershed were linked to agricultural practices and the use of synthetic fertilizers, but further investigations in other transformation processes that occur simultaneously should be evaluated. These results highlight an important nitrate removal capacity (i.e. denitrification) of the system, which may positively contribute to natural resilience against eutrophication. However, given the high intra and interannual hydrological fluctuations of Mediterranean aquatic systems, future studies on the relative contribution of nitrate sources and processes should increase spatio-temporal resolution of water sampling, and include measurements of groundwater and interstitial water as well as surface water.

Fluorescence-based monitoring of anthropogenic pollutant inputs to an urban stream in Southern California, USA

Fluorescence spectroscopy has been increasingly used to detect sewage and other anthropogenic contaminants in surface waters. Despite progress in successfully detecting bacterial and sewage inputs to rivers over diverse spatial scales, the use of fluorescence-based in-situ sensors to track contaminant inputs during storm events and to discern bacterial contamination from background natural organic matter (NOM) fluorescence have received less attention. A portable, submersible fluorometer equipped with tryptophan (TRP)-like and humic-like fluorescence sensors was used to track inputs of untreated wastewater added to natural creek water in a laboratory sewage spill simulation. Significant, positive correlations were observed between TRP fluorescence, the TRP:humic ratio, percent wastewater, and Escherichia coli concentrations, indicating that both the TRP sensor and the TRP:humic ratio tracked wastewater inputs against the background creek water DOM fluorescence. The portable fluorometer was subsequently deployed in an urban creek during a storm in 2018. The peak in TRP fluorescence was found to increase with the rising limb of the hydrograph and followed similar temporal dynamics to that of caffeine and fecal indicator bacteria, which are chemical and biological markers of potential fecal pollution. Results from this study demonstrate that tracking of TRP fluorescence intensity and TRP:humic ratios, with turbidity correction of sensor outputs, may be an appropriate warning tool for rapid monitoring of sewage or other bacterial inputs to aquatic environments.

Impact of tidally induced residual circulations on chemical oxygen demand (COD) distribution in Laizhou Bay, China

To understand the impact of hydrodynamics on pollutant transport in Laizhou Bay, China, we conducted numerical simulations using Mike 21. The model was calibrated with good agreements to field monitoring data at various monitoring stations. The simulation results show a clockwise and an anti-clockwise tidally-induced residual circulation in the western and eastern bay, respectively. Historical COD monitoring data also indicate two rings of high COD concentration in the same regions of the bay. This suggests that the hydrodynamics of tidal and residual currents is the main cause of the ring-shaped high COD concentration field in the bay. Pollutant inputs from inland rivers are also important for the COD distribution, making the near-shore side of the COD ring higher than the offshore side. Regions with higher retention time in the bay are usually associated with higher COD concentrations. This study is useful in understanding the mechanism of pollutant spatial distribution and subsequent pollution control in a sea bay.

Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro‐climate over the past 150 years

Rapid development and climate change in southeast Asia is placing unprecedented pressures on freshwater ecosystems, but long term records of the ecological consequences are rare. Here we examine one basin of Tasik Chini (Malaysia), a UNESCO‐designated flood pulse wetland, where human disturbances (dam installation, iron ore mining, oil palm and rubber cultivation) have escalated since the 1980s. Diatom analysis and organic matter geochemistry (δ13Corg and C/N ratios) were applied to a sediment sequence to infer ecological changes in the basin since c. 1900 CE. As the Tasik Chini wetland is a rare ecosystem with an unknown diatom ecology, contemporary diatom habitats (plant surfaces, mud surfaces, rocks, plankton) were sampled from across the lake to help interpret the sedimentary record. Habitat specificity of diatoms was not strongly defined and, although planktonic and benthic groupings were distinctive, there was no difference in assemblages among the benthic habitat surfaces. An increase in the proportion of benthic diatom taxa suggests that a substantial decrease in water level occurred between c. 1938 and 1995 CE, initiated by a decline in rainfall (supported by regional meteorological data), which increased the hydrological isolation of the sub‐basin. Changes in the diatom assemblages were most marked after 1995 CE when the Chini dam was installed. After this time both δ13Corg and C/N decreased, suggesting an increase in autochthonous production relative to allochthonous river flood pulse inputs. Oil palm plantations and mining continued to expand after c. 1995 CE and we speculate that inputs of pollutants from these activities may have contributed to the marked ecological change. Together, our work shows that this sub‐basin of Tasik Chini has been particularly sensitive to, and impacted by, a combination of human and climatically induced changes due to its hydrologically isolated position.

ПРОБЛЕМЫ ИСПОЛЬЗОВАНИЯ ИСТОЧНИКОВ НЕЦЕНТРАЛИЗОВАННОГО ВОДОСНАБЖЕНИЯ НА ТЕРРИТОРИИ ЮГА ТОМСКОЙ ОБЛАСТИ

Introduction. Sources of non-centralized water supply are the most important resource of drinking water for the population of rural areas. As a rule, water is taken from small depths, which makes it vulnerable to pollution. This type of water use is characterized by the absence of any preliminary water treatment. The constant use of groundwater for drinking can negatively affect the health of the local population since the indicators of its chemical and microbiological composition are not controlled in any way and do not always meet the quality standards. All this determines the relevance of the research conducted in the territory of the Tomsk District (Tomsk Region). Methods. Groundwater quality was assessed by comparing the concentrations of substances in the studied water samples with the background values established for the given territory in relation to Sanitary Norms and Regulations as well as microbiological indicators. Changes in the chemical and microbiological composition of the studied water, caused by economic activity, were taken as “pollution” as compared to the natural (background) state for this territory as well as sanitary and hygienic standards. Results. According to the results of studying the chemical composition of water, high levels of the following components were observed: total hardness, Na+, K+, SO42–, Cl–, NO3–, Fe, and Mn. As for NO3–, Fe, and Mn, their concentrations exceed manifold not only the background values but also the maximum allowable concentrations for drinking water. Microbiological analysis showed a large number of microorganisms from various physiological groups, which indicates a high degree of bacterial contamination of water. We present possible reasons for the input of pollutants into the water and review briefly the adverse health effects. Conclusion. In order to prevent the possible negative impact of excessive contents of various components in the chemical composition of water on the health of the local population, preliminary water treatment using available methods is recommended.

Study of groundwater vulnerability to contamination using the DRANTHVP method in wates groundwater Basin, Indonesia

Wates Groundwater Basin in Kulon Progo Regency, the Special Region of Yogyakarta, covers an area of 152.67 sq.m. With human occupations continuously growing in the regency, the groundwater in this basin is subject to change. This research was intended to identify the spatial distribution of groundwater vulnerability of Wates Groundwater Basin using the DRANTHVP method, which factors in Depth to Water Table (D), Recharge (R), Aquifer Thickness (A), Nitrate Attenuation Intensity (N), Topography (T), Groundwater Velocity (V), and Pollutant Input Intensity (P). The data were analyzed quantitatively using a weighted tiered approach―the rating was based on to what degree each of these factors contributes to the calculated vulnerability, then overlaid to produce a groundwater vulnerability map. From the analysis, the index values were clustered into three classes of groundwater vulnerability: low 4.48-6.35, medium 6.35-7.39, and high 7.39-7.97. A large proportion of the basin had medium groundwater vulnerability (109.16 sq.m), and less than half of it had low (39.63 sq.m) and high groundwater vulnerability (3.88 sq.m); these severity levels vary depending on the hydrogeological characteristics and land use of a study area.

Fishers' Ecological Knowledge about Marine Pollution: What Can FEK Contribute to Ecological and Conservation Studies of a Southwestern Atlantic Estuary?

The growth of human populations and industrial activities in the last decades have been the major cause of ecosystem decline, especially due to the inputs of several pollutants in the environment. Estuaries are one of the main concerns in marine governance because they receive potentially toxic substances from many sources that end up in the sea. Despite this, marine policies that aim to protect marine areas have dismissed local fishers' knowledge, although fishers have ecological knowledge that endorses and complements scientific research. Therefore, the aim of this study was to identify sources and indicators of pollution in the Bahia Blanca Estuary (BBE) according to the fishers and to contrast this knowledge with scientific studies. We conducted 20 interviews with the fishers of the BBE, and the results showed that all of them think the estuary is polluted and that there have been changes in the biomass of catches in the past. Most of them think that industries of the petrochemical complex are the major cause of pollution (57%), while marine organisms were the most mentioned items as indicators of pollution (59%), especially the commercial species (41%). We found interesting parallels between fishers' ecological knowledge (FEK) and scientific data. Thus, we conclude that FEK is an invaluable tool that provides data that could help to co-protect and co-manage this estuary and the services it provides.

Atmospheric Deposition of Coal-Related Pollutants in the Pacific Northwest of the United States from 1950 to 2016.

Coal-related elements are toxic and persistent pollutants that have spread globally since the industrial revolution, mainly from point-source emissions. A sediment core was collected from Deep Lake in northeastern Washington State (USA) by the Washington State Department of Ecology, with the aim of assessing recent changes in atmospheric deposition in the US Pacific Northwest. The core was divided into depth intervals and dated by lead-210. A sample from each cross section was digested and analyzed for toxic metals and metalloids using inductively coupled plasma-mass spectrometry. Data show recent increases in the concentrations of arsenic, barium, selenium, and mercury. Comparison with 1993 US Geological Survey ice core data from the Upper Fremont Glacier in Wyoming (USA), Asian coal consumption data, and weather patterns suggests that pollutant inputs to Deep Lake sediments are the result of coal-burning activities in the Asia-Pacific region. Most notably, mercury deposition in Deep Lake has increased from approximately 20 ppb in 1996 to 9470 ppb in 2014 (an ~400-fold increase), and since 1993 when the ice core was analyzed. Environ Toxicol Chem 2020;39:335-342. © 2019 SETAC.

Estuarine sediments are key hotspots of intracellular and extracellular antibiotic resistance genes: A high-throughput analysis in Haihe Estuary in China

Estuaries lie between terrestrial/freshwater and marine ecosystems, receive considerable pollutant input from land-based sources, and are considerably influenced by human activities. However, little attention has been paid to combined research on extracellular antibiotic resistance genes (eARGs) and intracellular ARGs (iARGs) in the estuarine environment. In this study, we profiled eARGs and iARGs in sediments from Haihe Estuary, China by adopting high-throughput quantitative PCR and investigated their relationship with mobile genetic elements (MGEs), the bacterial community and environmental factors. The results showed that the abundance of eARGs ranged from 9.06 × 106 to 1.32 × 108 copies/g and that of iARGs ranged from 3.31 × 107 to 2.93 × 108 copies/g, indicating that estuarine sediments were key hotspots of eARGs and iARGs. Additionally, multidrug resistance genes were both highly diverse and abundant in Haihe Estuary, especially in coastal samples. The high abundance of vancomycin and carbapenemase resistance genes may pose a potential health risk to human. Salinity altered the composition and structure of the bacterial community. Partial redundancy analysis showed that the bacterial community and MGEs appeared to be the major drivers of ARG variance in estuarine sediment. This study provides an overview of the distribution of eARG and iARG along the Haihe Estuary and draws attention to the need to control pollutants in estuary ecosystems.

An overview of management and monitoring of harmful algal blooms in the northern part of the Persian Gulf and Oman Sea (Hormuzgan Province).

Algal bloom as a common phenomenon in the Persian Gulf and the Sea of Oman had catastrophic effects on environmental, social, economic, and human health aspects from 2008 to 2009. Since 2008, the Persian Gulf and the Sea of Oman Ecological Research Institute (PGSOERI) has monitored and managed algal blooms in the Hormuzgan coast along the northern Persian Gulf and the Sea of Oman. Management strategies have included regular monitoring of chlorophyll, water quality, and remote sensing. In this regard, relevant departments and the Regional Organization for Protection of Marine Environment (ROPME) collaborated with each other to prevent and forecast algal blooms. We reviewed historical and current monitoring, mitigation, and management systems of algal blooms in the Hormuzgan coast. In addition, complications and challenges of algal bloom monitoring and management were also discussed. Documenting algal bloom monitoring and research, improving forecasting and modeling of blooms, educating the public and fishermen, developing a cooperative monitoring framework, and controlling pollution input entering the ROPME region are the main challenges of algal bloom management in the Hormuzgan coast.

Environmental Significance of Phosphorus Fractions of Phytoplankton-and Macrophyte-Dominated Zones in Taihu Lake

It is of great importance to study the environmental significance of phosphorus fractions in overlying water and sediments of typical phytoplankton-and macrophyte-dominated zones. It will help to clarify the process of phosphorus migration and transformation in the sediment-water interface, and has practical significance for understanding the eutrophication process and its treatment in different regions of Taihu Lake. The investigation was conducted within typical phytoplankton-and macrophyte-dominated zones of Taihu Lake over four seasons to analyze the spatial and temporal differences between phosphorus fractions in water and sediments, and reveal their environmental significance. The results showed that:① Total phosphorus (TP), total soluble phosphorus (DTP), dissolved inorganic phosphorus (DIP), and particulate phosphorus (PP) in the overlying water of phytoplankton-dominated zones were much higher than those in macrophyte-dominated zones. Most of them showed seasonal characteristics, which were higher in summer and autumn than in winter and spring. PP is the main component of TP, accounting for 71.8% to 89.6%. A similar distribution character was found in the content of chlorophyll (Chl-a) compared with phosphorus concentration in overlying water. ② The concentration of TP in the surface sediments of phytoplankton-dominated zones was 372.38-529.64 mg·kg-1, and that in macrophyte-dominated zones was 304.29-454.27 mg·kg-1. In surface sediments, concentrations of TP in phytoplankton-dominated zones were significantly higher than in phytoplankton-dominated zones. The highest TP concentrations appeared in winter, and the lowest in summer. These were owing to the input of exogenous pollution, and the migration and transformation of internal phosphorus between sediments and overlying water under different environmental conditions. ③ The order of the mass fraction of phosphorus in sediments was:NH4Cl-P < Fe-P < Org-P < Res-P < Al-P < Ca-P. Mobile-P=NH4Cl-P+Fe-P+Org-P, accounting for 9.10%-16.93% of TP in phytoplankton-dominated zones, and slightly higher in macrophyte-dominated zones, where it was 8.11%-13.50%. Res-P accounted for 10.06%-14.97% of TP in phytoplankton-dominated zones, and 11.02%-20.28% in macrophyte-dominated zones. The risk of internal phosphorus release in phytoplankton-dominated zones is high, which is not conducive to the fixation and burial of phosphorus. The eutrophication degree of different regions in Taihu Lake is obviously different, and different characteristics of phosphorus release and burial are showed. The phytoplankton-dominated zones deserve special attention because of their high internal phosphorus load and release potential.

A novel model for the contamination of a system of three artificial lakes

<p style='text-indent:20px;'>In this study, a new model has been developed to monitor the contamination in connected three lakes. The model has been motivated by two biological models, i.e. cell compartment model and lake pollution model. Haar wavelet collocation method has been proposed for the numerical solutions of the model containing a system of three linear differential equations. In addition to the solutions of the system, convergence analysis has been briefly given for the proposed method. The contamination in each lake has been investigated by considering three different pollutant input cases, namely impulse imposed pollutant source, exponentially decaying imposed pollutant source, and periodic imposed pollutant source. Each case has been illustrated with a numerical example and results are compared with the exact ones. Regarding the results in each case it has been seen that, Haar wavelet collocation method is an efficient algorithm to monitor the contamination of a system of lakes problem.

Air pollution inputs to the Mojave Desert by fusing surface mobile and airborne in situ and airborne and satellite remote sensing: A case study of interbasin transport with numerical model validation

Deserts are fragile and highly sensitive ecosystems that increasingly are affected by upwind urban areas and industrial activities. The Los Angeles Basin (LAB) contributes to poor air quality in downwind deserts including the Mojave Desert. Few studies have investigated potential air pollution inputs to the Mojave, whose fragile ecosystem includes endangered plant and animal species.Data were collected on 19 August 2015 by a mobile air quality laboratory, AMOG (AutoMObile trace Gas) Surveyor, that observed inputs can arise from the LAB as well as the San Joaquin Valley (SJV), California. The campaign used a strong methane (CH4) plume as a tracer for the downwind fate of emissions from Bakersfield area petroleum production and also measured ozone (O3). Additional in situ concurrent airborne GHG and O3 data were collected by AJAX - Alpha Jet Atmospheric eXperiment. Both AMOG and AJAX measure winds.Mojave Desert air quality was very poor (visibility ~4 km). Based on the winds, an additional source was inferred beyond the LAB and SJV Basins. Numerical transport modeling and analysis of aerosol lidar data collected the same day by the Cloud Profiling LiDAR onboard the Earth Research-2 stratospheric airplane demonstrated that fires in Northern California were responsible, with prevailing winds transporting air southwards along the eastern Sierra Nevada Range (Bishop Valley) to the Mojave.Whereas the southern and eastern Mojave are impacted by SJV and LAB outflow, the north Mojave generally avoids these inputs. This study shows it can be affected by even distant wildfires, which likely will increase in occurrence and intensity from climate change. Thus, regulatory efforts to reduce air quality impacts on the endangered Mojave ecosystem must include wildfires and also account for the significant differences between different regions of the Mojave. Currently, there is a paucity of studies, highlighting the critical need for field research.

Regulation-Induced Pollution Substitution

Abstract Environmental regulations may cause firms to reoptimize over pollution inputs. By regulating air emissions in particular counties, the Clean Air Act (CAA) gives firms incentives to substitute toward polluting other media, like waterways, and toward pollution from plants in other counties. I test these hypotheses using the EPA Toxic Release Inventory (TRI). Regulated plants increase their ratio of water-to-air emissions by 177% (102 log points) and their level of water emissions by 105% (72 log points). Regulation of an average plant increases air emissions at unregulated plants within the same firm by 11%.

Effects of copper exposure and increased temperatures on Collembola in western Washington, USA

In the city of Seattle and the surrounding Puget Sound region, increased human population and the resulting increased domestic and commercial transportation has led to higher inputs of heavy metal pollutants in the region, many of which have been shown to increase in toxicity for various organisms at higher temperatures. One pollutant of concern in the region is copper (Cu) from brake and tire attrition. The extent to which Cu can affect other organisms that are part of the Puget Sound ecosystem is largely unknown. We studied the effect of Cu exposure on two species of Collembola, one of which is a native species (Choreutinula americana Palacios-Vargas, Castaño-Meneses & Gao) inhabiting the region's epiphytic mosses and lichen while the other is a model species commonly used in ecotoxicology studies (Folsomia candida Willem). We then extended this work by examining the effect of Cu exposure when Collembola are exposed to increased temperatures as predicted by the B1 and A2 climate change scenarios. We found that the native Collembolan was significantly more sensitive to Cu than the model species when maintained under a constant 20 °C, suggesting that ecotoxicology studies using the model species F. candida might underestimate the effect of toxicants to native Collembola. We also observed that increased temperatures significantly lowered the tolerance of both species to Cu. The results of this study highlight the joint effect of warming temperatures and pollutants on a representative species of Collembola in the Pacific Northwest.

Heavy metals of sediment cores in Dachan Bay and their responses to human activities

The grain-size distributions and heavy metal content in two sediment cores from Dachan Bay were analyzed, and the vertical distribution, provenance, and ecological risk of heavy metal were evaluated. The concentrations (μg g−1) of Cu, Pb, Zn, Cd, Cr, Hg, As, and Ni in the sediment samples were 14.8–408, 33.0–130, 78.6–256, 0.193–1.79, 47.5–192, 0.052–1.39, 8.94–25.2, and 26.0–89.6, respectively. Most heavy metal concentrations increased from the bottom to the upper layers. On the basis of two sediment cores, the potential ecological risk of heavy metals was determined to be low, and the degree of potential ecological harm of heavy metals was in the order of Hg > Cd > As>Cu > Pb > Cr > Zn. Principal component analysis and correlation analysis yielded similar results, which indicated that heavy metals were closely related to the input of anthropogenic pollution (i.e., industrial pollutants and sewage discharge).

Global warming and acid atmospheric deposition impacts on carbonate dissolution and CO2 fluxes in French karst hydrosystems: Evidence from hydrochemical monitoring in recent decades

The long-term change in surface water chemistry over time in remote areas is usually related to global change, including several processes such as global warming and acid atmospheric pollution. These cumulative factors limit the quantitative interpretation of the global warming effect on surface water acidification in relation to the atmospheric CO2 sink. To quantitatively estimate the impact of global warming on the atmospheric/soil CO2 uptake by carbonate weathering, the approach proposed here involves discriminating the proportion of [Ca + Mg] in waters resulting from soil carbonic acid dissolution (equal to the amount of CO2 uptake from soil/atmosphere) from the proportion resulting from strong acid pollution. This approach was applied to 5 karst hydrosystems located in France, far from local pollution sources and with several decades of hydrochemical monitoring.[Ca + Mg] from acid deposition represented between 16 and 25% of the total [Ca + Mg] concentration and the flux was positively correlated with the atmospheric deposition flux. This [Ca + Mg] increase is associated with increasing [Mg] and was found to be driven by the acid pollution inputs. Equilibrating water with calcite in presence of carbonic acid will release [Ca + Mg] into solution. The input of strong acids from atmospheric pollution contributes more to magnesian calcite dissolution because its solubility is lower than that of calcite.Since the 1980s, the decrease in [Ca + Mg] production due to the decrease in acid atmospheric deposition has minimized the increase in [Ca + Mg] linked to CO2 partial pressure (pCO2) increasing with global warming. It was found that [Ca + Mg] from H2CO3 dissolution did not decrease with an increase in air temperature, as suggested by carbonate solubility. The annual fluxes of Ca + Mg from H2CO3 dissolution, calculated for an average flow, showed a positive gradient with air temperature, of about 0.061 mol m2 yr−1 °C−1 (±0.006). In low rainfall areas, the pCO2 increase with air temperature was stronger than in rainy areas. For an average specific discharge of 300 L m−2 yr−1, global warming is estimated to increase the CO2 uptake flux by about 204 micromol L−1 °C−1 (5.7% of the observed flux).

Spatio-temporal variations of sedimentary metals in a large suburban lake in southwest China and the implications for anthropogenic processes

Environment quality of suburban and urban lakes receives special attention due to their great impacted by human perturbations and important roles in ecosystem services. Herein, the spatio-temporal variations of 10 metal and metalloid elements in 13 sediment cores from a large suburban lake (Dianchi) were studied to explore the changes in sedimentary environment and pollution and their associations with human activities since the last century. Concentrations of each element were largely varied at spatial scales, but showed similar vertical trends among the profiles, suggesting comparable changes in sedimentary processes in each lake region. Cluster analysis showed two groups of elements: group I includes Al, Ti, Cu, Cr and Ni, and group II includes As, Cd, Hg, Pb and Zn. Temporally, concentrations of all elements were generally constant until the 1950s. Thereafter, group I elements along with the clay percentage started to decrease, indicating accelerated input of coarser soils due to strengthening human perturbation and changing land use. However, group II elements showed increasing values of concentrations, particularly the enrichment factors (EF = 1.0–10.8), which peaked between mid-1990s and 2000, indicating continued pollutants input with watershed economic development. With the implementation of environment management measures, pollution was initially restrained or reduced in recent decades as indicated by the stable EFs and sedimentary fluxes of Cd, Hg, Pb and Zn and decreasing values of As. Spatially, the stocks of anthropogenic As, Cd, Hg, Pb and Zn were higher in the northern while lower in the southern lake area. This spatial difference was mainly due to the large input of industrial and domestic wastewaters in the northern compared to the area in the southern that receives runoff from agricultural and forested land. Overall, the spatio-temporal patterns in accumulation of metal and metalloid elements in the lake reliably reflected the impacts of watershed human activities.

Simultaneous removal of phosphate and ammonium nitrogen from agricultural runoff by amending soil in lakeside zone of Karst area, Southern China

The loss of phosphorus(P) and nitrogen from agricultural non-point source(ANPS) is one of the main causes of eutrophication in rivers, lakes and reservoirs in the Karst region, southern China. The lakeside buffer zone has proven to be effective in reducing the input of ANPS pollutants. However, the interception efficiency of natural soil for P and ammonia nitrogen is insufficient to control ANPS pollution. In this study, natural zeolite(NZ), aluminium modified clay(AMC) and lanthanum modified bentonite(LaMB) were used to amend the natural soil collected in the lakeside zone of Kelan Reservoir, Guangxi, China. An experimental study was conducted to examine the dissolved inorganic P(DIP) and ammonia nitrogen removal efficiency and fixation mechanism of three amended soils under simulation conditions. The results showed that natural soil had a high fraction of clay and silt (particle size<20μm; 75.2 %), and had a high removal rate of >95 % for the DIP at the beginning of the experiment. With the intermittent input of farmland drainage, the P removal rate of natural soil from runoff decreased gradually. Compared with the control group, P removal rates of AMC- and LaMB amended soils remained at a high level within 46 days, with means of 93.6 % and 93.9 %. However, NZ amended soil has a weak interception capacity of runoff P pollutant. The chemical sequential extraction showed that AMC increased soil P capacity by forming NaOH-P and NaHCO3-P, while LaMB by forming NaOH-P, NaHCO3-P and Residual-P. In addition, LaMB amended soil can simultaneously remove ammonia from farmland runoff, with the removal rate of 89.3 %. AMC- and LaMB amended soils are proved to be potential and effective technologies for ANPS pollution control. This study provide an important basis for the treatment of ANPS pollutants and the construction of lakeside buffer zone in eutrophic watershed.