An improved technology for monitoring groundwater flow velocity and direction in fractured rock system based on colloidal particles motion.

The colloidal borescope, using colloidal particle motion, is used to monitor the flow velocities and directions of groundwater. It integrates advanced techniques such as microscopy, high-speed photography, and big data computing and enjoys high sensitivity at the micron level. However, In the same well, the groundwater flow velocity monitored by colloidal hole mirror is varies greatly from that obtained by conventional hydrogeological monitoring, such as pumping test. In order to solve this problem, the stability catcher and stratified packer are designed to control the interference of the vertical flow in drilling, and to monitor the flow velocity and direction of groundwater velocity at the target aquifer and target fracture. Five wells with different aquifers and different groundwater types were selected for monitoring in south-central China. The instantaneous velocity and direction are converted into east-west component and north-south component, the average velocity and direction is calculated according to the time of 10 min, and the particle trajectory diagram is established. Based on these results, it proposed a concept of cumulative flow velocity. Using curve-fitting equations, the limits of cumulative flow velocities as the monitoring time tends to infinity were then calculated as the actual flow velocities of the groundwater. The permeability coefficient of aquifer is calculated by using the fissure ratio of aquifer, hydraulic slope and flow velocity, and compared with the permeability coefficient obtained by pumping test. The results are as follows: (1) The variation coefficient of the instantaneous flow velocity measured at the same depth in the same well at different times is greater than that of the time average flow velocity and greater than that of the cumulative flow velocity. The variation coefficient of the actual velocity is the smallest, indicating that the risk of using the actual flow velocity is lower. (2) The variation coefficient of the flow rate monitored at different depths in the same well is mainly controlled by the properties of the aquifer. The more uniform water storage space in the aquifer, the smaller the variation coefficient. (3) The comparison between the permeability coefficient obtained by monitoring and the permeability coefficient obtained by pumping test shows that the flow of structural fissure water controlled by planar fissure is more surface flow, and the results are consistent. When the groundwater flow is controlled by pores and solution gaps, the flow channel is complicated, which is easy to produce turbulent flow, and the result consistency is poor. (4) According to different research accuracy requirements, different monitoring and calculation methods can be selected for different aquifers and groundwater types. Researches show that, the permeability coefficient calculated for the actual flow velocity in well DR01 is the same as that calculated for the pumping test. The aquifer characteristics reflected by the coefficient of variation of the actual flow velocity in the same aquifer are more realistic. The pumping test method obtains the comprehensive parameters of a certain aquifer, and this method can be used to monitor a certain fissure. In this paper, the new technology developed for monitoring, and the new algorithm established for data processing, can accurately obtain the flow velocity and direction of groundwater, using capsule hole mirror monitoring method. The key parameters of hydrogeology can be obtained by using one well, which can reduce the time and cost input and improve the work efficiency.

Extensive removal of thallium by graphene oxide functionalized with aza-crown ether.

Thallium (Tl) is a highly toxic heavy metal, and its pollution and remediation in aquatic environments has attracted considerable attention. To reduce or remove Tl pollution in the environment, various strategies have been applied. Graphene oxide (GO) has abundant oxygen-containing functional groups, indicating its high application potential for pollution remediation via methods involving binding to metal ions or positively charged organic molecules or electrostatic interaction and coordination. However, the adsorption of Tl to GO occurs via physical adsorption, for which the adsorption efficiency is low. Therefore, herein, we report a new method to effectively remove Tl pollution in water. We combined GO with aza-crown ether, which enhanced the electronegativity and ability to bind metal ions. The functionalized graphene oxide (FGO) demonstrated high efficiency through a wide pH gradient of 5-10, with a dominant Tl(i) adsorption capacity (112.21 mg g-1) based on the Langmuir model (pH 9.0, adsorbent concentration of 0.8 g L-1). The adsorption of Tl(i) during removal fit a pseudo-second-order kinetic model well. The mechanisms of Tl removal involve physical and chemical adsorption. In summary, our study provides a new method for the detection and treatment of Tl-containing wastewater by using FGO.

[Mobilization of Heavy Metals in a Soil-Plant System and Risk Assessment in the Dabaoshan Mine Area, Guangdong Province, China].

This study analyzed heavy metal concentrations in mining/agricultural soil and plant samples from the Dabaoshan mining-impacted region, Guangdong Province, and evaluated the corresponding health risks. The results showed that most of the soil samples exhibited a pH<5, which, in some cases, facilitated the release of Cu, Pb, and Al from soil and hence affected the availability for plant uptake. Farmland in Shaxi town was found to be seriously polluted by Cd, whereas the mining area was seriously polluted by Cd, Pb, Cu, and As, which present potential ecological risks. Farmland in Xinjiang town was seriously polluted by Cu, As, and Cd, and also present ecological risks for this area. The concentrations of heavy metals (especially Al and Fe) in the eight plant species assessed were mostly higher than that in plants grown in non-contaminated soil. Only 10% of the bioconcentration factors and 18% of the translocation factors were higher than 1 in the aerial parts of plants, indicating that most heavy metals were concentrated in plant roots. Heavy metal concentrations in shoots of Miscanthus and Blechnum orientale were not high, and their accumulation from soil to plant was poor. These plants are excluder species and can be used for in situ phyto-stabilization and management. Weeds like Soliva anthemifolia species in contaminated agricultural field showed a strong enrichment ability for Cd. Rice mainly accumulated As and Cd in the roots and belongs to root compartment plants.

[Accumulation of Heavy Metals in Agricultural Soils and Crops from an Area with a High Geochemical Background of Cadmium, Southwestern China].

In order to investigate the accumulation and transfer of heavy metals in agricultural soils and crops in an area with a high geochemical background of cadmium, soil and crop samples from a black shale outcropped area in Chongqing were collected and analyzed, and the results were then compared with those from other representative black shale outcropped areas. The results showed that some soil samples had a very low pH, and the metals Cd, Cr, Ni, and Zn were enriched. Cadmium concentrations in soil samples exceeded the safety limit, followed by Cr and Ni. Overall, 91.3% of soil samples were heavily to extremely polluted by Cd. The residual fractions accounted for more than 80% of the total metals, except for Cd and Pb. The weak acid soluble fraction of Cd accounted for 27.0%±6.4% of the total Cd, followed by Zn and Ni. The results demonstrate that weathering of black shales can result in elevated heavy metals in soils, and Cd is the primary contaminant in local soils. The high bioavailability of Cd and the high acidity of soils induced the enrichment of Cd in local crops. Cadmium has a higher transfer factor than other metals, and the crops were seriously polluted by Cd, particularly the leaf vegetables, which presented a high concentration of 11.5 mg·kg-1 based on dry weight, and thus, these vegetables are not suitable for cultivating as food stuff. In addition, the risks from Cr should be of concern as well. Therefore, it is recommended that countermeasures be carried out to address the pollution situation, for example, by classifying the pollution levels of agricultural soils and adjusting the planting structures accordingly to reduce the health risks to local inhabitants.

[Spatial Distribution, Sources and Bioavailability of Heavy Metals in the Surface Sediments of Longjiang River, Southern China].

In order to evaluate the pollution status, possible sources, and bioavailability of heavy metals (As, Cd, Pb, Sb, Zn, and Tl), 33 surface sediments were collected from Longjiang River, Southern China. The total concentrations and potential bioavailable concentrations of the heavy metals were analyzed using ICP-MS. Enrichment factors (EFs), Pearson correlation analysis, and principal component analysis (PCA) were used to further assess their pollution degree and potential sources. Results showed that the surface sediments of Longjiang River have been suffering heavy metal (As, Cd, Pb, Sb, and Zn) pollution to different degrees. The maximum concentrations of As, Cd, Pb, Sb, and Zn were 67.0, 7.42, 227, 229, and 807 mg·kg-1, respectively, while the Tl concentration were very low, with little variation. Moreover, the polluted sites were mostly located in the mid-lower of the main stem and in tributaries (Dongxioajiang and downstream of Dahuanjiang), and the pollution degree of the heavy metals, in a descending order, were Cd > Sb > Zn > Pb > As > Tl. Pearson correlation analysis and PCA indicated that As, Cd, Pb, Sb, and Zn predominantly originated from anthropogenic inputs, including nonferrous metal mining and smelting, municipal sewage, and agricultural activities, and Tl mostly derived from natural rock weathering. The bioavailability of heavy metals in the sediments tended to be controlled by their sources. The percentages of bioavailable heavy metals (As, Cd, Pb, Sb, and Zn) in the highly anthropogenic impacted areas (the mid-lower of the main stem and downstream of Dongxiaojiang tributary) were also high, with the average percentages of bioavailable As, Cd, Pb, Sb, and Zn of 26%, 51%, 49%, 38%, and 47%, respectively. High EF values and high bioavailable percentages of heavy metals easily and greatly cause high ecological risk of Longjiang River.

[Spatial Distribution Characteristics and Potential Ecological Risk of Antimony and Selected Heavy Metals in Sediments of Duliujiang River].

In order to investigate the spatial distribution characteristics of Sb and selected heavy metals, and to discriminate their sources and potential ecological risks in surface sediments of the Duliujiang river,a total of 62 surface sediment samples were collected in this study. Total contents of Sb, As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Tl, Zn and Fe in these samples were measured by inductively coupled plasma mass spectrometry(ICP-MS) and the inductive plasma optical emission spectrometry(ICP-OES). Principal component analysis(PCA) and Pearson correlation analysis were used to deduce the potential sources of these elements. Geo-accumulation index(Igeo), enrichment factor(EF) and Hakanson's potential ecological risk index(Eri and RI) were calculated to evaluate the pollution degree of heavy metals in sediments. The results indicated that the contents of heavy metals in sediments were impacted by human activities to different extents, and the Duliujiang River was significantly contaminated by Sb. The contents of Sb in sediments reached up to 7080 mg·kg-1, and gradually decreased from upstream to downstream, while the contents of As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Tl and Zn varied indistinctively. The PCA results showed that the cumulative proportion of the first two components accounted for 77.67% of the total variables, suggesting that two major sources of Sb and other heavy metals were mining/smelting industry and natural sources. The calculated Igeo and EFs also showed that the surface sediments of the Duliujiang River were majorly polluted by Sb, followed by As and Co, lightly contaminated with Co, Cu, Mo, Ni, Pb and Tl, and uncontaminated with Cr. The ecological hazards(Eri) for each metals in a descending order were Sb > Cd > As > Co > Ni > Pb > Cu > Zn > Cr. The comprehensive index of potential ecological risks(RI) for heavy metals indicated that 58.1% of the 62 sediments samples had more than moderate ecological risks, and the sites with high RIs were generally located around Sb mining area and the downstream of the Baluo River. In addition, the Eri of Sb was a predominant component of RI, indicating that the Duliujiang River is an area with extremely high potential ecological risk of Sb.

[Cadmium and selected heavy metals in soils of Jianping area in Wushan County, the Three Gorges region: distribution and source recognition].

Abnormally high cadmium (Cd) concentrations were existed in soils of Jianping area in the Three Gorges region, but little information is available about the geochemical distribution of Cd and source identification. In the present paper, total contents of Cd and other selected heavy metal elements, the characteristics of soil, the contents of Cd in typical soil profiles, and chemical forms of Cd in selected soils were studied. The correlation analysis, the principal component analysis, and the comparison between different soil types were conducted. The concentration distribution of Cd and selected elements in local soils was investigated and their sources were identified. The results showed that Cd in local rocks, coal and coal wastes ranged from 0.22-101 mg x kg(-1), 0.42-42 mg x kg(-1) in the arable topsoil, and 0. 12-8.5 mg x kg(-1) in natural soils. The soils were also rich in other elements such as V, Cr, Ni and Zn. The weak acid fraction of Cd accounted for 17%-35% of total contents. This study demonstrated that soils from the Jianping area of Wushan County had a serious Cd pollution, and both local rocks and soils display a significant geochemical interrelation. Cd particularly accumulates in the topsoil, and it is mainly derived from the geogenic source. Human such as the historical coal mining may overload Cd in the soils. The local soils had a high portion of bioavailable Cd, through which Cd may easily transfer to and accumulate in the local crops growing in the Cd-rich soils and cause potential health risk to local residents.

[Distribution of arsenic in surface water in Tibet].

This research was aimed on studying the arsenic distribution of water in Yarlung Zangbo and Singe Zangbo basins in Tibet. Results showed that arsenic concentrations were different in different types of the water. The sequence of arsenic concentration from high to low was hot spring water (4920 microg x L(-1) +/- 1520 microg x L(-1), n =2), salt lake water (2180 microg x L(-1) +/- 3840 microg x L(-1), n =7), well water (194 microg x L(-1), n = 1), freshwater lake water (163 microg x L(-1) +/- 202 microg x L(-1), n =2) and stream water (35.5 microg x L(-1) +/- 57.0 microg x L(-1), n=74). The high arsenic concentration in surface water in Singe Zangbo and the upstream of Yarlung Zangbo were found. The average concentration of arsenic in water from Singe Zangbo (58.4 microg x L(-1) +/- 69.9 microg x L(-1), n = 39) was significantly higher than that from Yarlung Zangbo (10.8 microg x L(-1) +/- 16.9 microg x L(-1), n = 30). Arsenic concentration in 43.2% of stream water samples and all of the hot springs, saline lakes and well water were higher than 10 microg x L(-1). Yarlung Zangbo and Singe Zangbo are important sources of drinking water for the local people. There is a high risk for the local people who may suffer from chronic arsenic poisoning.

Elevated yield of monacolin K in Monascus purpureus by fungal elicitor and mutagenesis of UV and LiCl.

In China, Monascus spp., a traditional fungus used in fermentation, is used as a natural food additive. Monascus spp. can produce a secondary metabolite, monacolin K namely, which is proven to be a cholesterol-lowering and hypotensive agent. Hence, recently, many researchers have begun focusing on how to increase the production of monacolin K by Monascus purpureus. In the present study, we investigated the effect of the fungal elicitor and the mutagenesis of UV & LiCl on the amount of monacolin K produced by Monascus purpureus. The fugal elicitor, Sporobolomyces huaxiensis, was isolated from tea leaves and its filtrate was added into the culture filtrate of Monascus purpureus during growth to induct the production of monacolin K. The results showed that the highest amount of monacolin K produced by the liquid fermentation was 446.92 mg/mL, which was produced after the fungal elicitor was added to the culture filtrate of Monascus purpureus on the day 4; this amount was approximately 6 times greater than that of the control culture filtrate, whereas the highest amount of monacolin K produced by the mutated strain was 3 times greater than the control culture after the irradiation of UV light in the presence of 1.0 % LiCl in the medium.

Elevated yield of Monacolin K in Monascus purpureus by fungal elicitor and mutagenesis of UV and LiCl

In China, Monascus spp., a traditional fungus used in fermentation, is used as a natural food additive. Monascus spp. can produce a secondary metabolite, monacolin K namely, which is proven to be a cholesterol-lowering and hypotensive agent. Hence, recently, many researchers have begun focusing on how to increase the production of monacolin K by Monascus purpureus. In the present study, we investigated the effect of the fungal elicitor and the mutagenesis of UV & LiCl on the amount of monacolin K produced by Monascus purpureus. The fugal elicitor, Sporobolomyces huaxiensis, was isolated from tea leaves and its filtrate was added into the culture filtrate of Monascus purpureus during growth to induct the production of monacolin K. The results showed that the highest amount of monacolin K produced by the liquid fermentation was 446.92 mg/mL, which was produced after the fungal elicitor was added to the culture filtrate of Monascus purpureus on the day 4; this amount was approximately 6 times greater than that of the control culture filtrate, whereas the highest amount of monacolin K produced by the mutated strain was 3 times greater than the control culture after the irradiation of UV light in the presence of 1.0 % LiCl in the medium.

[Environmental concerns on geochemical mobility of lead, zinc and cadmium from zinc smelting areas: western Guizhou, China].

Indigenous zinc smelting activity, widely spread in western Guizhou, China, had caused serious pollution of heavy metals of lead (Pb), zinc (Zn) and cadmium (Cd) in soil and water and posed risk to the local ecosystem. Geochemical distribution and mobility of Pb, Zn and Cd in soil, waste residue and waters were investigated in a small watershed in order to provide scientific base for the approach to pollution control and remediation. Concentrations of Pb, Zn and Cd in smelting residues averaged at 4 632 mg/kg, 8 968 mg/kg, and 58 mg/kg, respectively; whereas Pb 234 mg/kg, Zn 400 mg/kg and Cd 9.6 mg/kg in average in the soils around the smelting areas were measured. The sequential geochemical extraction test showed that Pb, Zn and Cd in the contaminated soils had high mobility and bioavailability for the metals, whereas smelting waste residues had lower mobility and bioavailability because their concentrations presented small percentages (all less than 0.2%) in the exchangeable fraction. Concentrations of Pb, Zn and Cd were high in the local stream water but low in groundwater. In the surface water, Pb, Zn and Cd were significantly concentrated in the suspended sediment. The results indicated that metal-rich erosion process of smelting residue and contaminated soil contributed to mobility of the metals into stream water.

[Geochemical distribution and environmental quality of cadmium in river sediment around the Jinding Pb-Zn mine area in Yunnan].

A long-term mining activity of Jinding Pb-Zn mine area in Yunnan has caused the serious cadmium pollution to the river sediments of the ambient area. The Cd contents of Beidagou river sediments (mean value <10 mg x kg(-1)) are lower than those of Nandagou river sediments (mean value = 266 mg x kg(-1)). The Cd contents of river sediments in different section of Bijiang river occur distinct difference. The Cd contents are rather lower in upstream sediments of Bijiang river, and increase substantially along downstream contaminated section of Bijiang river. The Cd pollution coefficient is higher (R = 21.9-45.2) than Zn (R = 4.9-9.7) and Pb (R = 2.7-4.6). The degree of pollution is estimated by the geoaccumulation index, which indicates the following rank of pollution elements: Cd > Zn > Pb. The river sediments are extremely contaminated in Nandagou river and downstream section of Bijiang river from Nandagou, strongly contaminated in most part of Beidagou river, moderately to strongly contaminated in few river section of Nandagou river, uncontaminated or moderately contaminated in upstream of Bijiang river from Jinding. The heavy metals pollution of river sediments presents increasing trend from Nandagou outlet to Wenzhuang section of Bijiang river.

[Limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou].

With indigenous zinc smelting waste residue, contaminated soil and background soil as test substrates, a pot experiment was conducted to study the growth characteristics of Lolium perenne and Trifolium pretense on these substrates. The results showed that the major limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou were the salt-alkali stress and the lower contents of organic matter, total N, available N and total K. The heavy metals in waste residue had a high concentration, but their available forms only occupied a small proportion, with low toxicity to plant but having potential harmful risk. Contaminated soil had lower concentrations of heavy metals than waste residue, but its contained heavy metals were more in available form. The constraints of revegetation on contaminated soil were the toxicity of heavy metals and the low contents of available P and K. Mixing contaminated soil with zinc smelting waste residue could be one of the effective approaches for the substrate amendment in indigenous zinc smelting areas.