High TDS Research Articles

Site investigation of open dumping site of Municipal Solid Waste in Faisalabad

Inappropriately solid waste handling and disposing are promoting environmental problems in Pakistan. Deteriorating environmental quality is a serious consequence of open dumping site and is rapidly increasing concern for public. To investigate, the causes Muhammada Wala dumping site was chosen. There is a tremendous amount of solid waste generating and dumped without any precautionary measures. Due to development of industries and urban areas the condition is going to be harsh. The aim of this study is the site investigation of the dumping site and its consequences on environment. Water samples were collected near the site, analyzed in the laboratory and interviews were taken. Significant high TDS was observed in ground water. Communicable diseases and unhygienic environment were revealed from this research. The main collapses of municipal solid waste systems are unplanned management of the city, intense climatic conditions, absence of awareness of users and community participation, inadequate resources including machinery and lack of funds.

Assessment of Drinking Water Quality Status and its Impact on Health in Tandojam City

Unsafe drinking water is one of the major concerns in developing countries. The southern Sindh is province of Pakistan that adjoins the Arabian Sea coast where the drinking water quality is deteriorating due to unrefined urban waste and excessive use of agro-chemicals. Present study aimed to assess the quality of ground water source and to compare it with WHO standards. Water borne diseases associated with drinking it in the vicinity Tandojam city were identified. Water from ground water source was sampled at selected locations in the study area. The samples were collected mostly from pumped waters. The samples were analyzed for physico-chemical properties in order to identify the quality problems and suggest safe source for drinking purpose. Findings revealed that the ground water quality in Muzaffrabad colony is deteriorating. The situation was much worse in Muzaffrabad colony, Jam Ghar and Mir colony with high TDS and salty taste, respectively at few sampling locations. In addition, laboratory analysis of the water quality parameters revealed the detail of variation in the groundwater. TDS, hardness, sodium (Na), chloride (Cl) and magnesium (Mg) etc. were considerably beyond the WHO permissible limits. The poor quality of the water has created different waterborne diseases like cholera, diarrhea etc. Moreover, the samples of SAU Colony and Amar Town showed that the water quality of these areas was within acceptable limits according to WHO standards and was suitable for the purpose of drinking.

The Effect of Water Chemistry on Thermochemical Sulfate Reduction: A Case Study from the Ordovician in the Tazhong Area, Northwest China

Formation water chemistry, sulfate sulfur isotopes, and associated H2S contents and sulfur isotopes were measured from the Ordovician in Tazhong area, Tarim Basin. The aim is to elucidate the effects of geochemical composition of formation water on thermochemical sulfate reduction (TSR) and potential usage of SO4/Cl ratios as a new proxy for TSR extents in areas, where H2S and thiaadamantanes (TAs) data are not available. The formation water has SO4/Cl ratios from 0.0002 to 0.016, significantly lower than 0.04 to 0.05 from 3 to 7 times evapoconcentrated seawater. Thus, the low values are explained to result from TSR. Furthermore, the SO4/Cl ratios show negative correlation relationships to TAs and H2S concentrations, indicating that TSR occurred in a relatively closed system and SO4/Cl ratio can be used to indicate TSR extents in this area. Extensive TSR in the Cambrian in the Tazhong area, represented by low SO4/Cl ratios and high H2S and TAs concentrations, is accompanied by formation water with high TDS and Mg concentrations, indicating the effects of water chemistry on TSR under a realistic geological background. In contrast, the low TSR extent in the Ordovician may have resulted from limited TSR reaction duration and total contribution of aqueousSO42-.

Genesis and evolution of high-pCO2 groundwaters of the Mukhen spa (Russian Far East)

We present the chemical and isotope compositions of the water and gas phases of the unique Mukhen cold high-pCO2 spa. Estimated 518O, 5D, and 513Ctic values and data on geology and hydrogeology of the studied area indicate that the source of the groundwaters is meteoric waters, whereas carbon dioxide is of deep genesis and numerous regional faults are gas-feeding channels. Calculations of equilibrium reactions in the water-rock system show that the upper-aquifer waters (HCO3-Ca-Mg) with low TDS are undersaturated with carbonate minerals, montmorillonites, and aluminosilicates but are oversaturated with kaolinite, whereas the lower-aquifer waters (HCO3-Na) with high TDS are oversaturated with calcite, dolomite, and clay minerals but are undersaturated with main aluminosilicates. We propose a new concept of the formation of these groundwaters, demonstrating that long interaction between rocks and groundwaters in the presence of CO2 and considerable precipitation of secondary minerals are responsible for the high TDS of the lower-aquifer waters (up to 14 g/L) and their geochemical type (HCO3-Na) and unusual isotope composition (518O = -25.2%c, 5D = -69.0%c).

Evidence of trace element emission during the combustion of sulfide-bearing metallurgical slags

The present study shows the results of field and laboratory studies of trace element transfer from waste heaps of metallurgical slags (Kemerovo region, town of Belovo). Temperature anomalies were observed, with high temperatures up to 81.2 °C on the top of the heap. A visual geophysical model of the inner parts of the heap with contrasting resistivity zones was obtained using the electrical resistivity tomography (ERT) method, and quantitative characteristics were derived. Dry and frozen slag zones were characterized by resistivity of 50–500 Ohm·m. The resistivity of wet slag varied from 5 to 10 Ohm·m for slag with low humidity of 1–2 Ohm·m for slag saturated with highly mineralized solutions. The local anomaly of extremely low resistivity (0.3–0.5 Ohm·m) might be associated with a combustion centre or high pore solutions TDS. Basic major elements (Ca, Mg, K, Na, Si, and Al), metals (Cu, Zn, Pb, and Cd) and anionic elements (As, Sb, and V) were determined in gas condensates in situ. The most volatile elements were basic elements: Ca > Cu > Mg > Na > Mn > Fe, Zn. Lower concentration in the condensates was determined for Si > K > As > Sr > Al > V and Pb, Ba, La were also found. The observed mineral paragenetic sequences were primary minerals of barite-polymetallic ores and sphalerite concentrate, high-temperature minerals formed during pyrometallurgical processing and/or permanent combustion of the heap surface, efflorescence minerals formed by atmospheric oxidation accelerated by acid steam condensation. An experimental investigations using stepwise and 500 °C heating of the same samples were performed to compare the elements that were released into the gas phase in situ and off-site.

STUDI TINGKAT BAHAYA EROSI DAN PENGARUHNYA TERHADAP KUALITAS AIR (TSS DAN TDS) DAS SEJORONG, KECAMATAN SEKONGKANG KABUPATEN SUMBAWA BARAT PROVINSI NUSA TENGGARA BARAT

The purposes of this research are to study the degree of erosion hazard and its influence on water quality in Sejorong watershed. Survey method was used in this research. The locations of soil sampling were divided into two locations that are native and disturbed areas. Soil samples were taken on 4 locations. Water samples were taken on 2 locations which lying from upstream and downstream. The degree of erosion hazard known by combining the surface erosion estimated using USLE from Wischmeier and Smith (1978) and the depth of the soil. The result of this research had shown that the surface erosion ranging from 0.21 to 6.916.3 t/a/year. The most of surface erosion and the degree of erosion hazard occurred in Jalit I. The analyze of water quality showed that Jalit WI, that located near Jalit I and Jalit II, has the highest TDS, that is 2500 mg/l.

Assessment of geochemical processes in the unconfined and confined aquifers in the Eastern Ganges Basin: a geochemical approach

Groundwater quality is gaining more importance in groundwater management due to rapid growth in population, agriculture and industrial sectors worldwide. The goal of the present study is to evaluate the groundwater chemistry and to identify the geochemical processes governing the water chemistry in the shallow unconfined and deeper confined aquifers in the Eastern Ganges Basin using geochemical methods. Groundwater samples were analysed for major ions and metals (Fe, Mn, Zn, Cu, Pb and As). Shallow wells are found to have high pH, EC, TDS, Ca, Mg, Cl and SO4, and low HCO3/Cl ratio compared to the deep wells. However, the average concentration of Na, HCO3, NO3, PO4, F and Mn is not significantly varied with depth which indicates that the variation in the water chemistry between unconfined and confined aquifers is not only due to the natural processes but also indicates that surface contamination sources could have affected the water chemistry in the unconfined aquifer. In the unconfined aquifer, processes like wastewater infiltration, denitrification, reverse ion exchange and mineral weathering govern the water chemistry. The water chemistry in the confined aquifer is regulated by weathering of silicate and carbonate minerals and regional flow.

Phytoremediation potential of a novel fern, Salvinia cucullata, Roxb. Ex Bory, to pulp and paper mill effluent: Physiological and anatomical response

The study was conducted with an aim to remediate effluent from a pulp and paper mill, after treating it for 28 days with an aquatic fern, Salvinia cucullata. The effluent had high BOD, COD, TS, TSS, TDS, P, hardness and chloride, and several heavy metals (Cd, Cu, Cr, Ni, Pb, Mg, Mn, Fe and Zn) above national limits. However, the plant survived a wide range of effluent concentrations (25%, 50%, 75% and 100%, v/v), and flourished well, particularly at 25% (v/v), resisted membrane injury and generation of H2O2 and O2, showed better growth and induced all the major antioxidant enzymes. The plants also induced lipid peroxidation. Most of the elemental profiles were higher than the toxic levels stipulated for plants, indicating tolerance to metal. In fact, barring Fe, for Cr, Cu, Pb, Zn, Mg and P, at all the effluent doses, and for Cd, Ni and Mn, up to 75% (v/v) effluent, greater concentrations were observed in leaf than in root. This plant was more suited for nutrient removal, as it effectively reduced BOD, Zn, Fe, Ni, Mg, P and increased dissolve oxygen. Further, pH, hardness, chloride, TS and Mn was reduced optimally by 25–50% (v/v) treatments. SEM revealed prominent structural damages from 50 to 100% treatments. Presence of Pb as well as Fe in the EDX peaks were observed in the cortex rather than in the root vascular zone. This plant could be suggested to be an effective phytoremediator of multi-contaminant effluent with maximum benefit at low doses (25–50%, v/v).

Groundwater flow and geochemical evolution in the Central Flinders Ranges, South Australia

The chemical characteristics of water in the Oratunga Area, Central Flinders Ranges, South Australia have been used to evaluate and determine the processes controlling water chemistry in addition to the sources of ions. The isotopic analysis results show that the groundwater is mainly meteoric. Based on the rock and water chemistry, ionic ratios, hydrochemical facies and saturation indices, the chemical evolution has been studied. The chemistry of groundwater revealed two types of water. Thus, in high topographic areas, low TDS, bicarbonate and mixed water types are dominated and support a rapid and direct recharge. While in the low topographic areas, high TDS and chloride compositions are the most common attributed to the accumulation of ions and groundwater evolution. Analysis of the ion concentration, head data and saturation indices shows a compositional trend that can be studied as an evolutionary system. The ionic ratios and hydrogeochemical modelling using NETPATH was used to quantify and verify the different hydrochemical processes. The resulting data shows that calcite dissolution/precipitation and cation exchange reactions are the major processes affecting groundwater chemical evolution of the groundwater in the basin. This study has provided a basis for a better understanding of the hydrogeologic setting in areas of a little data.

Evaluation of groundwater chemistry and its impact on drinking and irrigation water quality in the eastern part of the Central Arabian graben and trough system, Saudi Arabia

The present study deals with the assessment of groundwater with respect to the main hydrological processes controlling its chemistry and its subsequent impact on groundwater quality for drinking and irrigation purposes in the eastern part of the Central Arabian graben and trough system. Groundwater samples were collected from 73 bore wells tapping the Cretaceous Biyadh and Wasia sandstone aquifers. The main groundwater facies in the area belong to the mixed CaMgSO4/Cl type and the SO4Cl type. Prolonged rock water interaction has resulted in high TDS (average of 2131 mg/l) and high EC (average of 2725 μS/cm) of the groundwater. The average nitrate (56.38 mg/l) value in the area is higher than the WHO prescribed limits of 50 mg/l in drinking water and is attributed to agricultural activities. The Drinking Water Quality Index (DWQI) shows that 33% of the water samples fall within the excellent to good category whereas the remaining samples fall in the poor to unsuitable for drinking category. In terms of Sodium Adsorption Ratio (SAR), Sodium percentage (Na %) and Residual Sodium Carbonate (RSC) the groundwater is suitable for irrigation however the high salinity values can adversely affect the plant physiology.

Trace element geochemical evolution and groundwater origin in North Rukuru–Songwe alluvial aquifer of northern Malawi

This study used multivariate analysis and geochemical modeling to appreciate the trace element evolution in North Rukuru–Songwe alluvial aquifer of northern Malawi. From the isotopic studies, the δ2H/δ18O ratios revealed that groundwater is of meteoric origin through vertical recharge and mixing processes. The isotopic depletion along the west–east transect is due to mixing and fractionation processes. Generally, the d-excess value approximated the y-intercept of global meteoric water line of 10, which ruled out the influence of secondary evaporative processes on isotopic variation. Hierarchical cluster analysis identified four distinct clusters (C1, C2, C3 and C4) in the study area. Among these four clusters, it was observed that C1 had relatively high median concentrations of Fe (716.7 µg/L), Cr (0.85 µg/L), Pb (7.90 µg/L) and Sb (3.80 µg/L), while C2 was characterized by high levels of Cu (3.20 µg/L). Cluster 3 was comparably defined by high median levels of F (1.00 mg/L) and Mn (338 µg/L), while C4 revealed high median concentrations of As (8.70 µg/L), Ba (635 µg/L), Li (22.2 µg/L), Ni (2.80 µg/L), Se (6.20 µg/L) and Sr (677 µg/L). Clusters C1 and C4 described a flow path along the North Rukuru River, which is characterized by higher levels of evaporites as shown by higher concentrations of Na, K, Cl and SO4. It was also observed that this path was defined by high levels of HCO3 and total hardness. The principal component analysis suggests that carbonate dissolution and silicate weathering are the main mineralization control mechanisms. Furthermore, it is revealed that samples in the west had higher factor scores for As, Ba, Li, Ni, Se and Sr (with higher TDS), while the eastern is characteristic of higher heavy metals (Fe and Pb). Geochemical modeling using PHREEQC showed that surface complexation reactions significantly impact trace elements of higher redox state. In addition, inverse modeling confirms the significance of carbonate dissolution, silicate weathering and cation exchange processes along the North Rukuru River flow path.

Aquifer vulnerability and seawater intrusion risk using GALDIT, GQISWI and GIS: case of a coastal aquifer in Tunisia

Due to increase in population and agricultural activities, the Sfax coastal aquifer is under tremendous stress and seawater intrusion becomes a serious concern. This situation needs an assessment of aquifer vulnerability and seawater intrusion risk. A new approach for vulnerability mapping using GALDIT, groundwater quality index for seawater intrusion (GQISWI), geostatistics, the Ghyben–Herzberg model and GIS was developed. The model is used to determine the trend of groundwater contamination by seawater intrusion in the coastal aquifer in Sfax basin (Tunisia). Vulnerability assessment method is recognized through assessing weight and ratings of the GALDIT relevant parameter. A second vulnerability map was realized based upon the groundwater quality index for seawater intrusion integrating the water quality parameters for delineating seawater intrusion in the aquifer. The validation of GQISWI and GALDIT vulnerability maps was undertaken through comparison of areas of high Jones Ratio, chloride and TDS concentration and their relative vulnerability index. The Ghyben–Herzberg model has been used to predict the actual seawater intrusion extend and evaluate the freshwater–saltwater dynamics. The results reveal that the coastal area is currently undergoing seawater intrusion and its northern part is the most affected one by this contamination.

Treatment of the pesticide industry effluent using hydrodynamic cavitation and its combination with process intensifying additives (H2O2 and ozone)

Hydrodynamic cavitation (HC) and its combination with H2O2 and ozone have been applied in the present work for the treatment of industrial pesticide effluent. Initially, the effect of dilution of the effluent on the efficacy of hydrodynamic cavitation has been studied using circular venturi as a cavitator. Although an increase in the extent of dilution has not shown any beneficial effect on the actual moles of pollutant degraded, hybrid processes have been studied using 1:5 dilution due to very high TDS content of the effluent. Treatment of the industrial pesticide effluent using HC+ozone (3g/h) process has demonstrated that the biodegradability index (BI) of the effluent increases from 0.123 to 0.324 after 2h of operation. The rate of COD and TOC reduction has also increased by many folds by using HC in combination with ozone. In addition this, the treatment of industrial pesticide effluent using HC+H2O2 has also indicated that the rate of COD and TOC reduction increases significantly by using HC in combination with various loadings of H2O2. The study of interference of added H2O2 on the COD analysis has exhibited that the COD equivalence is 0.441mg/L for 1mg/L of H2O2. The energy efficiency and operating cost of various hybrid processes have been compared based on the cavitational yield and the cost of electricity. The combined process of HC and H2O2 has observed to be the most cost-effective one due to its higher cavitational yield and lower power consumption.

Characteristics of Stable Isotopes in an Inland Lake and Their Implications for Water Management in Northwestern China

Bosten Lake is the largest inland freshwater lake in China, functioning as a critical control and allocation facility for agricultural, industrial, ecological and social development in southern Xinjiang in northwestern China. The distribution of stable isotopes, spatial and temporal variations of δ18O, and hydrograph separation of Bosten Lake and its principal recharge rivers—the Kaidu River and the Huangshuigou River—were analyzed using isotope composition. Hydrograph separation indicated that Bosten lake water comprised four components as follows: river runoff, groundwater, agricultural and industrial drainage, and local precipitation. Their contributions were 31%, 35%, 25%, and 9%, respectively. Irrigation drainage and industrial wastewater, enriched high TDS, were the main factors affecting the water quality of Bosten Lake. The δ18O of lake water, which was significantly reduced compared with river water, remained below the local meteoric water line (LMWL), indicating strong evaporation in the lake, especially during summer. The spatial and temporal distribution of δ18O exhibited slow water circulation in the lake. Both the Kaidu River and the Huangshuigou River depend on alpine precipitation and glacier snow, especially the Kaidu River, where ice-snow-melt water accounts for 43% of the river runoff. These rivers are sensitive to climate change. The Bosten Lake inflows would be reduced by the decrease in river runoff and groundwater under future climate change. To improve water quality and reduce evaporative loss, the amount of wastewater should be strictly restricted by local government, and water diversions from Bosten Lake should be concentrated between May and September.

Comparison of Different Parameters of Four Selected Industrial Effluents in Chittagong Metropolitan, Bangladesh

A study was executed at Nasirabad Industrial Area, Chittagong to compare important parameters of industrial effluents viz. physical, chemical and heavy metals from four types of industries such as steel, textile, chemical and garments. For sample collection three points were selected from each industry – discharging, mixing and universal points. Then all collected samples were analysed by using pH electrode, DO electrode, sension 156 portable multiparameter meter, and spectrophotometer etc. It revealed that effluents from garment industry were awfully polluted, they exposed the lowest DO value (1.0 mg/L) and highest TDS (512 mg/L), EC (1135 mho/cm) and BOD (76.66 mg/L), COD (326 mg/L), Chromium (0.283 mg/L), Zinc (0.041 mg/L) and Lead (0.69 mg/L). Most of the cases the second point showed surpassing effluents accumulated. Comparatively, steel industry was found less contaminated as-well-as in all industries universal points wherein all parameters showed the values is under standard level due to natural assimilative capacity.

Vinasse application to sugar cane fields. Effect on the unsaturated zone and groundwater at Valle del Cauca (Colombia)

Extensive application of vinasse, a subproduct from sugar cane plantations for bioethanol production, is currently taking place as a source of nutrients that forms part of agricultural management in different agroclimatic regions. Liquid vinasse composition is characterised by high variability of organic compounds and major ions, acid pH (4.7), high TDS concentration (117,416–599,400mgL−1) and elevated EC (14,350–64,099μScm−1). A large-scale sugar cane field application is taking place in Valle del Cauca (Colombia), where monitoring of soil, unsaturated zone and the aquifer underneath has been made since 2006 to evaluate possible impacts on three experimental plots. For this assessment, monitoring wells and piezometers were installed to determine groundwater flow and water samples were collected for chemical analysis. In the unsaturated zone, tensiometers were installed at different depths to determine flow patterns, while suction lysimeters were used for water sample chemical determinations. The findings show that in the sandy loam plot (Hacienda Real), the unsaturated zone is characterised by low water retention, showing a high transport capacity, while the other two plots of silty composition presented temporal saturation due to La Niña event (2010–2011). The strong La Niña effect on aquifer recharge which would dilute the infiltrated water during the monitoring period and, on the other hand dissolution of possible precipitated salts bringing them back into solution may occur. A slight increase in the concentration of major ions was observed in groundwater (~5% of TDS), which can be attributed to a combination of factors: vinasse dilution produced by water input and hydrochemical processes along with nutrient removal produced by sugar cane uptake. This fact may make the aquifer vulnerable to contamination.

Hydrogeochemical processes between surface and groundwaters on the northeastern Chinese Loess Plateau: Implications for water chemistry and environmental evolutions in semi-arid regions

A large area of the continents is covered by loess that is subject to fast erosion, but detailed research is lacking about processes influencing the hydrogeochemistry in loess-covered regions. This study presents the first δ18O and δD, and major ion contents of various waters (rain, rivers, lake, springs and wells) from Daihai Lake catchment on the Chinese Loess Plateau (CLP). In combination with historical hydrological and meteorological data during the past 60years, we investigate factors affecting water chemistry and lake evolution on the CLP, and thereby provide insight into hydrogeochemical processes under semi-arid climatic conditions.On the northeast CLP, river and groundwaters show elevated TDS (450 and 461mg/L, respectively), about ~4 times higher than the global river mean value. Their water chemistry is dominantly influenced by carbonate weathering. Lake waters show even higher TDS at 5758mg/L, ~50 times of the global mean, which is attributed to strong evaporation and associated with precipitation of calcite and dolomite. The order of carbonate (calcite and dolomite) saturation indexes follows lake water>river water>groundwater. Downstream rivers to the west of Daihai Lake are characterized by elevated SO42−, indicating high lake levels in the past. Comparison of δ18O, δD, TDS and ion contents of river and groundwaters implies that shallow groundwaters are derived from surface runoff via fast infiltration, a hydrological process different from limited infiltration of groundwater on the Tibetan Plateau. Water quality assessment indicates that all river and 79% of well waters belong to moderately hard to hard-fresh waters, suitable for drinking and irrigation of plants with moderate salt tolerance. In contrast, all lake and spring waters and 21% of well waters belong to very bad water quality, and hence are not suitable for irrigation or drinking.Owing to intensified human activities under drying and warming climate, the lake water level of Daihai declined by 4.83m from 1955 to 2003, and started to accelerate since 1980. As a result, TDS and Cl− increased by 1.8 times and Mg/Ca rose by 156 times from 1953 to 2010. Our data show that environment degradation poses a great threat to human occupation on the CLP. Considering the uniformity of loess, hydrogeochemical processes between surface and groundwaters on the loess regions may represent a widespread status of the CLP.

Groundwater classification and its suitability in Kadaladi, Ramanathapuram, India using GIS techniques

The hydrochemical characteristics of groundwater in Kadaladi Block of Ramanathapuram district, Tamilnadu have been evaluated based on different indices for drinking, industrial and irrigational purposes using “HYCH” program. Groundwater samples were collected in pre-monsoon and post-monsoon of 2012 from 36 locations and analyzed for major ions. The abundance of the major ions is in the order of Na+ > Ca2+ > Mg2+ > K+ and Cl− > HCO3− > SO42− > NO3− > PO43−. Interpretation of analytical data shows that most part of the study area is occupied with groundwater having higher TDS which is not suitable for drinking purpose. High to very high nature of hardness and corrosivity restricts groundwater use for the industrial purpose. SAR and RSC indicate that 70 % of the groundwater is suitable for irrigation in both the seasons. Spatial distribution map of USSL salinity classification shows that 70 % of the area comes under high to very high saline nature and medium to high sodium content makes the groundwater which is only suitable for high tolerant crops. Above statement is further supported by Schoeller and Stuyfzand classification, where most of the samples fall under the Type IV water and Brackish to Hyperhaline water. Gibbs and Langlier Saturation Index shows that 70 % of the groundwater sample chemistry is due to rock–water interaction followed by evaporation.

Current perspectives on unconventional shale gas extraction in the Appalachian Basin

The Appalachian Basin is home to three major shales, the Upper Devonian, Marcellus, and Utica. Together, they contain significant quantities of tight oil, gas, and mixed hydrocarbons. The Marcellus alone is estimated to contain upwards of 500 trillion cubic feet of natural gas. The extraction of these deposits is facilitated by a combination of horizontal drilling and slick water stimulation (e.g., hydraulic fracturing) or “fracking.” The process of fracking requires large volumes of water, proppant, and chemicals as well as a large well pad (3–7 acres) and an extensive network of gathering and transmission pipelines. Drilling can generate about 1,000 tons of drill cuttings depending on the depth of the formation and the length of the horizontal bore. The flowback and produced waters that return to the surface during production are high in total dissolved solids (TDS, 60,000–350,000 mg L−1) and contain halides (e.g., chloride, bromide, fluoride), strontium, barium, and often naturally occurring radioactive materials (NORMs) as well as organics. The condensate tanks used to store these fluids can off gas a plethora of volatile organic compounds. The waste water, with its high TDS may be recycled, treated, or disposed of through deep well injection. Where allowed, open impoundments used for recycling are a source of air borne contamination as they are often aerated. The gas may be “dry” (mostly methane) or “wet,” the latter containing a mixture of light hydrocarbons and liquids that need to be separated from the methane. Although the wells can produce significant quantities of natural gas, from 2–7 bcf, their initial decline rates are significant (50–75%) and may cease to be economic within a few years. This review presents an overview of unconventional gas extraction highlighting the environmental impacts and challenges.

Effect of Indomie industrial effluent discharge on fish fauna of New Calabar River, Port Harcourt

The effect of Indomie industrial effluent discharge on the fish fauna of New Calabar River was investigated in order to ascertain the influence of BOD, COD, DO, TDS, TSS, pH, salinity, phosphate and temperature on the composition and distribution of fish fauna. The diversity of the fish fauna was found to be poor, only 12 fish species in 6 families were identified. The highest number (10) of fishes was recorded in station 4 while the least number (1) of fishes was observed in station 1. The fish families were: Cichlidae (38.89%), Clupidae (33.33%), Pomadasyidae (16.67%), Bagridae (11.11%) while Genidae and Muglidae had zero percentage of fishes in its abundant. The resident fish species (Ethmalosa fimbriata and Tilapia guinensis) were highly adapted to the changes in the study environment and this was dependent on their trophic relationship within the environment. These species had great affinity for indomie industrial waste, because they feed on waste remains, mud/sediment silts and annelids, juveniles of shrimps and crabs. The deterioration of water quality was evident by the high BOD (12.80mg/L), COD (130mg/L), TDS (37mg/L), TSS (62mg/L), pH (5.2), salinity (50.54mg/L), phosphate (0.14mg/L) and temperature (270C) as well as the low dissolved oxygen (2.8mg/L) values observed. It was recommended that a routine treatment of the effluent before discharge into the water should be carried out so to maintain safe levels of industrial effluent in the immediate and extended environment. Keywords: Effluent, pollution, environment, fish and fauna.