The utilization of brackish water, protecting the quality of the upper fresh water layer in coastal aquifers

Increasing salinity is one of the most significant and widespread forms of groundwater pollution in coastal areas. This paper presents the causes and impacts of saline water intrusion in coastal areas. Various causes of salt water intrusion, and approaches for the determination of its extent and various measures to control the salt water intrusion are described. An aquifer performance test (APT) approach is presented to identify the extent of existing salt water intrusion in the study area located in the southwest coastal region of Gujarat State (India). A resistivity based experimental technique is used to identify the quality of the groundwater available at different depths. A methodology is presented to assess the extent of available fresh and saline groundwater and to find out the limit up to which lower saline groundwater can be withdrawn for industrial purposes without affecting the upper fresh water layer which can be made available for domestic purposes.     

Modelling of lindane transport in groundwater of metropolitan city Vadodara,Gujarat, India

Migration pattern of organochloro pesticide lindane has been studied in groundwater of metropolitan city Vadodara. Groundwater flow was simulated using the groundwater flow model constructed up to a depth of 60 m considering a three-layer structure with grid size of 40?×?40?×?40 m³. The general groundwater flow direction is from northeast to south and southwest. The river Vishwamitri and river Jambua form natural hydrologic boundary. The constant head in the north and south end of the study area is taken as another boundary condition in the model. The hydraulic head distribution in the multilayer aquifer has been computed from the visual MODFLOW groundwater flow model. TDS has been computed though MT3D mass transport model starting with a background concentration of 500 mg/l and using a porosity value of 0.3. Simulated TDS values from the model matches well with the observed data. Model MT3D was run for lindane pesticide with a background concentration of 0.5?μg/l. The predictions of the mass transport model for next 50 years indicate that advancement of containment of plume size in the aquifer system both spatially and depth wise as a result of increasing level of pesticide in river Vishwamitri. The restoration of the aquifer system may take a very long time as seen from slow improvement in the groundwater quality from the predicted scenarios, thereby, indicating alarming situation of groundwater quality deterioration in different layers. It is recommended that all the industries operating in the region should install efficient effluent treatment plants to abate the pollution problem.     

Supporting the risk management process with land information: a case study of Australia

It is frequently argued that, at the parcel level, 1 stakeholders are capable of and well supported in managing their land‐related risks. Yet, evidence from the contemporary Australian context suggests otherwise: numerous large‐scale disaster events have revealed that citizens are ill‐prepared to respond and recover adequately. This paper begins with the premise that information, specifically land information, could better support parcel‐level risk preparation, mitigation, response, and recovery. State land administration organisations in Australia primarily maintain this information and make it accessible. Land information is used regularly across all levels of government to support risk management activities; however, such application has not always occurred at the parcel and citizen level. Via a case study approach, this paper initially explores the land information available in Australia to stakeholders interested in parcel‐level detail, and then goes on to propose how the utilisation of parcel‐level land information could serve to enhance risk management practices.     

Application of ameliorated wood pulp to recover Cd(II), Pb(II), and Ni(II) from e-waste

In this study, dl-malic acid and hydrogen peroxide were used as leaching agents to remove metals from e-waste (printed-circuit boards) and itaconic acid-grafted poly(vinyl alcohol)-encapsulated wood pulp (IA-g-PVA-en-WP) to uptake metals from leachate with high proficiency [11.63 mg g^?1; 93.03 % for Cd(II), 11.90 mg g^?1; 95.18 % for Pb(II), and 12.14 mg g^?1; 97.08 % for Ni(II)]. Metals were recovered from the loaded biosorbent by desorption studies. The standard analytical techniques, such as elemental analysis, Fourier-transform-infrared spectroscopy, scanning electron microscopy, atomic force microscopy, and thermogravimetric analysis, were used to characterize the recovering agent (biosorbent). At equilibrium, the metal uptake data were fitted to Langmuir and D–R isotherms (R ² > 0.99) significantly, revealing, the homogeneous distribution of active sites on biosorbent’s backbone. The possible mechanism appeared to be ion exchanges of metal ions with H⁺ together with binding over functionalities (COO^?). Dimensionless equilibrium parameter (R _L) showed the favourability of metal uptake at lower concentration, while mean adsorption energy (E) certified the physical binding of metal on functionalities which was further confirmed by sticking probability and activation energy parameters. Reusability studies were also conducted to state the performance of biosorbent.     

Associations between concentrations of selected perfluoroalkyl acids and concentrations of blood cadmium,lead, and total mercury

Environmental Science and Pollution Research - Data (N = 2552) from National Health and Nutrition Examination Survey for US adults aged ≥ 20 years for 2011–2016 were analyzed to...     

Protective role of zeolite on short- and long-term lead toxicity in the teleost fish Heteropneustes fossilis.

The high ion-exchange capacity of zeolite (sodium aluminium silicate) enhances the removal of lead from water, thus decreasing its availability to fish. Zeolites are very important in the field of environmental preservation due to the low cost and ecological compatibility. Zeolites can adsorb metallic ions by cation exchange reactions. Continuous exposure of the teleost fish Heteropneustes fossilis to sublethal concentrations of lead nitrate in water solution for short (35 days) and long (120 days) periods decreased both the soluble protein, RNA and glycogen contents in the liver and the body weight, but increased the cholesterol content. The presence of zeolite in the exposure solution decreased all of the adverse effects. In fish exposed to zeolite as feed additive, all the parameters improved in comparison to control fish, indicating that zeolites can be used safely in biological systems.     

Size distribution and source identification of total suspended particulate matter and associated heavy metals in the urban atmosphere of Delhi

A study of the atmospheric particulate size distribution of total suspended particulate matter (TSPM) and associated heavy metal concentrations has been carried out for the city of Delhi. Urban particles were collected using a five-stage impactor at six sites in three different seasons, viz. winter, summer and monsoon in the year 2001. Five samples from each site in each season were collected. Each sample (filter paper) was extracted with a mixture of nitric acid, hydrochloric acid and hydrofluoric acid. The acid solutions of the samples were analysed in five-particle fractions by atomic absorption spectrometry (AAS). The impactor stage fractionation of particles shows that a major portion of TSPM concentration is in the form of PM0.7 (i.e. <0.7microm). Similarly, the most of the metal mass viz. Mn, Cr, Cd, Pb, Ni, and Fe are also concentrated in the PM0.7 mode. The only exceptions are size distributions pertaining to Cu and Ca. Though, Cu is more in PM0.7 mode, its presence in size intervals 5.4-1.6microm and 1.6-0.7microm is also significant, whilst in case of Ca there is no definite pattern in its distribution with size of particles. The average PM10.9 (i.e. <10.9microm) concentrations are approximately 90.2%+/-4.5%, 81.4%+/-1.4% and 86.4%+/-9.6% of TSPM for winter, summer and monsoon seasons, respectively. Source apportionment reveals that there are two sources of TSPM and PM10.9, while three and four sources were observed for PM1.6 (i.e. <1.6microm) and PM0.7, respectively. Results of regression analyses show definite correlations between PM10.9 and other fine size fractions, suggesting PM10.9 may adequately act as a surrogate for both PM1.6 and PM0.7, while PM1.6 may adequately act as a surrogate for PM0.7.     

Autoheated thermophilic aerobic sludge digestion and metal bioleaching in a two-stage reactor system

A two-stage process has been developed for stabilization of sludge and removal of heavy metals from the secondary activated sludge with high rate of energy and time conservation.The first stage of the process involves autoheated thermophilic aerobic digestion at 55-60°C inoculated with less-acidophilic thermophilic sulfur-oxidizing microorganisms(ATAD).The results show that it is possible to maintain the autoheated conditions(55-60°C) in the ATAD reactor up to 24 hr,leading to reduction of 21% total solids(TS),27% volatile solids(VS),27% suspended solids(SS) and 33% volatile suspended solids(VSS) from the sludge.The sludge pH also decreased from 7 to 4.6 due to the activity of less-acidophilic thermophilic microorganisms.In the second stage operation,the digested sludge(pH 4.6,TS 31.6 g/L) from stage one was subjected to bioleaching in a continuous stirred tank reactor,operated at mean hydraulic retention times(HRTs) of 12,24 and 36 hr at 30°C.An HRT of 24 hr was found to be sufficient for removal of 70% Cu,70% Mn,75% Ni,and 80% Zn from the sludge.In all,39% VSS,76% Cu,78.2% Mn,79.5% Ni and 84.2% Zn were removed from the sludge in both the stages.