A computer-based program for the assessment of water-induced contamination in irrigated lands

The non-point characteristic of agrarian contamination hinders its quantification and assignation to a specific territory. The objectives of this work were to unify methodological criteria for agro-environmental evaluation and to propose indices to quantify irrigation-induced contamination. The computer program Irrigation Land Environmental Evaluation Tool (in Spanish, EMR; http://www.jcausape.es/investigacion/EMR.htm ) was developed to evaluate the quality of irrigation and the agro-environmental impacts, based on the water, salt, and nitrate balances in the hydrological irrigation basins. The behavior of the proposed indices was analyzed using data registered in various irrigation districts in the Ebro valley (Spain). The Salt and Nitrate Contamination Indices (SCI and NCI, respectively) were based on the unitary mass of exported pollutants, corrected by the "natural and socioeconomic" conditions of the irrigation districts evaluated. SCI and NCI were related to water and nitrogen use, key factors in minimizing contamination. SCI and NCI admit a greater mass of exported pollutants in disadvantaged irrigation districts, which does not allow the exclusion of adequate management in any evaluated irrigation lands. EMR is a user-friendly tool at the service of the agro-environmental surveillance of irrigation lands.     

Integrated approach for demarcating subsurface pollution and saline water intrusion zones in SIPCOT area: a case study from Cuddalore in Southern India

This paper deals with a systematic hydrogeological, geophysical, and hydrochemical investigations carried out in SIPCOT area in Southern India to demarcate groundwater pollution and saline intrusion through Uppanar River, which flows parallel to sea coast with high salinity (average TDS 28, 870 mg/l) due to back waters as well as discharge of industrial and domestic effluents. Hydrogeological and geophysical investigations comprising topographic survey, self-potential, multi-electrode resistivity imaging, and water quality monitoring were found the extent of saline water intrusion in the south and pockets of subsurface pollution in the north of the study area. Since the area is beset with highly permeable unconfined quaternary alluvium forming potential aquifer at shallow depth, long-term excessive pumping and influence of the River have led to lowering of the water table and degradation of water quality through increased salinity there by generating reversal of hydraulic gradient in the south. The improper management of industrial wastes and left over chemicals by closed industries has led surface and subsurface pollution in the north of the study area.     

A statistical approach for the assessment and redesign of the Nile Delta drainage system water-quality-monitoring locations

There are several deficiencies in the statistical approaches proposed in the literature for the assessment and redesign of surface water-quality-monitoring locations. These deficiencies vary from one approach to another, but generally include: (i) ignoring the attributes of the basin being monitored; (ii) handling multivariate water quality data sequentially rather than simultaneously; (iii) focusing mainly on locations to be discontinued; and (iv) ignoring the reconstitution of information at discontinued locations. In this paper, a methodology that overcomes these deficiencies is proposed. In the proposed methodology, the basin being monitored is divided into sub-basins, and a hybrid-cluster analysis is employed to identify groups of sub-basins with similar attributes. A stratified optimum sampling strategy is then employed to identify the optimum number of monitoring locations at each of the sub-basin groups. An aggregate information index is employed to identify the optimal combination of locations to be discontinued. The proposed approach is applied for the assessment and redesign of the Nile Delta drainage water quality monitoring locations in Egypt. Results indicate that the proposed methodology allows the identification of (i) the optimal combination of locations to be discontinued, (ii) the locations to be continuously measured and (iii) the sub-basins where monitoring locations should be added. To reconstitute information about the water quality variables at discontinued locations, regression, artificial neural network (ANN) and maintenance of variance extension (MOVE) techniques are employed. The MOVE record extension technique is shown to result in a better performance than regression or ANN for the estimation of information about water quality variables at discontinued locations.     

Natural resource protection on buffer lands: integrating resource evaluation and economics

Environmental managers are faced with the wise management, sustainability, and stewardship of their land for natural resource values. This task requires the integration of ecological evaluation with economics. Using the Department of Energy (DOE) as a case study, we examine the why, who, what, where, when, and how questions about assessment and natural resource protection of buffer lands. We suggest that managers evaluate natural resources for a variety of reasons that revolve around land use, remediation/restoration, protection of natural environments, and natural resource damage assessment (NRDA). While DOE is the manager of its lands, and thus its natural resources, a range of natural resource trustees and public officials have co-responsibility. We distinguish four types of natural resource evaluations: (1) the resources themselves (to the ecosystem), (2) the value of specific resources to people (e.g. hunting/fishing/bird-watching/herbal medicines), (3) the value of ecological resources to services for communities (e.g. clean air/water), and (4) the value of the intact ecosystems (e.g. forests or estuaries). Resource evaluations should occur initially to provide information about the status of those resources, and continued evaluation is required to provide trends data. Additional natural resource evaluation is required before, during and immediately following changes in land use, and remediation or restoration. Afterwards, additional monitoring and evaluations are required to evaluate the effects of the land use change or the efficacy of remediation/restoration. There are a wide range of economic methods available to evaluate natural resources, but the methods chosen depend upon the nature of the resource being evaluated, the purpose of the evaluation, and the needs of the agencies, natural resource trustees, public officials, and the public. We discuss the uses, and the advantages and disadvantages of different evaluation methods for natural resources.     

Impact of model parameterization on predictive uncertainty of regional groundwater models in the context of environmental impact assessment

Parameterization strategy impacts models' outputs and the associated uncertainty. This is particularly true for transient regional groundwater models where parameters can only be weakly constrained by insufficient observations. However, this is rarely investigated under any particular model structure. This study bridges this gap using a regional groundwater model developed to understand the impact of coal seam gas extraction on groundwater systems in a probabilistic framework. Two different parameterization schemes were implemented for hydraulic conductivity and specific storage. The first method solely relies on the relationship between hydraulic properties and burial depths. The second more complex strategy allows more spatial variations of hydraulic parameters using pilot points. The study provides new insights and practical guidance on the application of groundwater modelling for environmental impact assessment. The results suggest that the choice of model parameterization has a significant influence on predictive uncertainty. The model using the simple parameterization provides predictions with a much wider range than the model with a more sophisticated parameterization. This is because that the lowly parameterized model tends to generate more extreme effective hydraulic parameter fields unless the parameterization simplification converts the inverse problem to a (close to) well-posed problem that rarely exists for applied regional groundwater modelling. The potential impact of model parameterization should be discussed explicitly in groundwater modelling applications to support decision making to avoid misinterpretation of the modelling results.     

Impact of CNG implementation on PAHs concentration in the ambient air of Delhi: A comparative assessment of pre- and post-CNG scenario

The use of alternative fuel is considered to be an effective measure to improve the urban air quality. Concerned over deteriorating air quality in Delhi, the Delhi government initiated different measures including stringent emission norms, improved fuel quality and above all introduction of cleaner fuel-CNG in public transport system. The entire city bus fleet was converted to CNG mode by 2002. The present study reports the comparative assessment of the status of air quality with respect to PM(10) and PAH before and after the introduction of CNG in public transport system in Delhi. The study has been carried out for two different time periods: first in the year 1998 and second in the year 2004. Following the total conversion of public transport system to CNG in 2002, Post-CNG data indicate a sharp reduction of 51-74% in the PM(10) concentration and 58-68% in the TPAH concentration as compared to the Pre-CNG data.     

Ecotoxicological assessment of acid mine drainage: electrophysiological changes in earthworm (Aporrectodea caliginosa) and aquatic oligochaete (Lumbriculus variegatus)

Ecological health of 15 sites in two mining areas on the West Coast of the South Island, New Zealand, was assessed using a non-invasive electrophysiological technique. The conduction velocity (CV) changes in the medial giant fibres (MGF) of the terrestrial earthworm Aporrectodea caliginosa were measured on days 0, 1, 2, 4, 7, 14, and 21 following exposure to soil and/or sediment from six acid mine drainage (AMD) sites, and aquatic oligochaete Lumbriculus variegatus at 0, 3, 6, and 24 h following exposure to water from 14 AMD sites. The colour of the soil/sediments varied from red-brown to black with pH ranging from 4.46 to 7.37. The colour of AMD water samples varied from clear, black, brown to orange, and the pH ranged from 2.99 to 7.66. The CV decreased progressively in A. caliginosa exposed to most soil and sediment samples from the AMD sites (compared with controls exposed to soil from an organic farm) and this was most evident in measurements taken at 7 days. Based on the CV measurements taken on day 7, sites 3 > 2 > 1 were significantly (P < 0.05) the most toxic to earthworms. The CV of L. variegatus exposed to AMD water sampled from many sites also decreased progressively and this was significantly lower than the controls in the measurements taken at 24 h from sites 3 > 9 > 7 > 11. It is proposed that MGF CV in A. caliginosa and L. variegatus worms can be used as a non-invasive, sensitive, biomarker to monitor the toxicity of AMD sites.     

Study on water quality and genotoxicity of surface microlayer and subsurface water in Guangzhou section of Pearl River

In order to understand the water quality and the genotoxicity of various surfaces in the Guangzhou section of the Pearl River during January to December of 2008, we investigated and studied the current water situation of the surface microlayer (SML) and the subsurface water (SSW) in Guanzhou section (Zhongda Dock and Yuzhu Dock) of the Pearl River by chemical analysis and biological monitoring method (Vicia faba micronucleus test). The results showed that during these months concentrations of the indexes of the two docks water such as total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD) exceeded the national III level of surface water quality, and the indexes of SML were much higher than the ones of SSW (P?< 0.05), and the exceeding rate of TN, TP of SML was 100%. According to the eutrophic evaluation standard, the water bodies of SML and SSW in the two docks were in a eutrophication during these months. The eutrophication and pollution of SML was more serious, and the highest index of eutrophication (E value) was up to 81.9, which also had obvious difference with COD and TP (P?< 0.05). The water of SML in the two docks enriched to N, P, and chlorophyll a (Chl. a) seriously, and the enrichment factor of SML in Zhongda Dock to N, P, and Chl. a was 0.71 ?? 2.78, 0.98 ?? 1.18, and 0.49 ?? 13.99, respectively, and the one in the Yuzhu Dock was 1.09 ?? 1.52, 1 ?? 1.14, and 0.72 ?? 4.07, respectively. Through inspecting the water genotoxicity of various layers by V. faba micronucleus test, we could know that the average annual MCN?? of SML and SSW in the two docks was 6.09??, 5.53??, 5.57??, and 5.249??, respectively. In general, the above value of SML was a little higher than the one of SSW, but there was not a remarkable difference (P?> 0.05). This research shows that the water quality in a medium to heavy eutrophication in the Guangzhou section of Pearl River belongs to national III ?? IV level, and SML has the capability of enrichment to the pollutants such as N and P and induces the increase of micronucleus rate of V. faba tip cell. The study also indicates that there may be genotoxicity matters such as N, P in water body.     

Impact assessment of pesticide residues in fish of Ganga river around Kolkata in West Bengal

An investigation was conducted from 2001 to 2005 for determining the residual concentration of five pesticides, viz., total-HCH, total-DDT, total-Endosulfan, Dimethoate and Malathion in fish samples collected from various points of the river Ganga. Fish samples were analyzed for pesticide residues using standard laboratory procedures by GC method. It was found that total-HCH concentration remains above the MRL values for maximum number of times in comparison to four other pesticides. The pesticide contamination to fish may be due to indiscriminate discharge of polluted and untreated sewage-sludge to the river. The pesticide contents in some places are alarming. Thus proper care, maintenance, treatment and disposal of sewage water and sludge are most vital and should be the prime thrust for the nation.     

An appraisal of subsurface geology and groundwater resources of Owerri and environs based on electrical resistivity survey and borehole data evaluation

The research was aimed at determining the depth to the watertable, aquifer thickness and subsurface geology of the studyarea thus revealing its groundwater distribution as well as its potential as a substitute to the surface water resources.Vertical electrical soundings were carried out in the study area with maximum electrode spread. The Schlumberger electrode configuration technique was adopted. VES data were processedusing Schlumberger analysis package. Lithologic logs of alreadyexisting boreholes in the study area were collected, evaluatedand comparison were carried out. The results reveal alternatinglayers of sands, sandstones, gravel and clay. The lithologiclogs revealed that the study area is underlain by coastal sands (Benin formation). The water table varies from 10–64 m and thickness of the aquifer ranges from 20–80 m. Results show that the study area is underlain by a thick extensive aquifer that has a transmissivity of 2.8 × 10^-2m² s^-1 to 3.3 × 10^-1m² s^-1 and storativity 1.44 × 10^-4 to 1.68 × 10^-3m s^-1 values. The specific yield is about 0.31.The sandy component of the study area forms more than 90% ofthe sequence, therefore the permeability, the transmissivity andthe storage coefficient are high with an excellent source of groundwater resources.     

Effects of copper on development and survival rate of Paphia malabarica Chemnitz larvae under low saline condition

Venerid clam, Paphia malabarica Chemnitz, is the commercially exploited species distributed exclusively in Vembanad Lake and Ashtamudi estuary, along the south west coast of India. In this study, the survival rate and development of P. malabarica larvae were studied for 3 days in ambient salinity (33), copper (2.5 microg Cu2+ l(-1)), reduced salinities (25 and 20) and a combination of copper in low salinities. No significant differences were found in larval development between treatments. The survival rates decreased considerably with low salinities although the combination of copper and low salinity gave synergistic effects. The reduced survival in low salinities would limit population growth of this species in estuarine areas experiencing low salinities and also explains the absence of larval settlement on habitats close to harbors or river mouths.     

Impact assessment of various parameters polluting Ganga water in Kolkata Region: a study for quality evaluation and environmental implication

The quality of sewage-sludge samples obtained in Kolkata region was evaluated. Both sewage water and sludge components were analyzed for a number of physico-chemical, microbiological parameters using standard laboratory procedures, some heavy metals by AAS method and pesticide contents by GC method. Some of the physical and chemical constituents of the samples are within the allowable levels while the rest are not. The samples are rich in nutrients and have suitable pH for agricultural uses. In terms of Electrical Conductivity and Sodium Adsorption Ratio, sewage water is not suitable for irrigation. Fecal and coliform bacterial population is high in all samples. Pesticide and heavy metals in some places are alarming. So sewage-sludge produced in Kolkata cannot be used for agricultural purpose without any treatment. Thus proper care, maintenance, treatment and disposal of sewage water and sludge are most vital and should be the prime thrust for the nation.     

Environmental and socio-economic impacts of pipe drainage in Pakistan

Many drainage schemes and salinity control projects have been executed world wide. Pipe drainage has widely been used in Pakistan, Egypt and India to control waterlogging. The impact of pipe drainage on land and water was evaluated in this paper using data of three pipe drainage projects in Pakistan namely Khushab Salinity Control and Reclamation Project, Fourth Drainage Project in Faisalabad and Swabi Salinity Control and Reclamation Project. Data by regular monitoring of these projects were collected. The effect of pipe drainage on water table depth at these three locations has been compared. Water quality and soil salinity improvement due to the pipe drainage has also been investigated. Data, related to water table depths and discharges from drain pipes/wells, was collected. Observation wells, installed at various places by the Water and Power Development Authority, were used for collection of this data. To evaluate the impact of the projects on salinity, soil samples from all the three locations were tested. A questionnaire was prepared to get the view of the people about the projects. It was revealed that in these areas, due to subsurface pipe drainage, the percentage of the abandoned land has been considerably decreased. Over drainage was observed in a few places of the projects. The farmers at such places were asked to change their cropping patterns. Ultimately, there has been an increase in area under cultivation, crop yields and cropping intensity in the projects’ area.     

The effect of saline water disposal: implications for monitoring programs and management

In an effort to combat rising groundwater tables andexpanding saline lakes, saline water has been disposedof into the aquatic environment, despite there beinglittle information as to the environmental effects.Monitoring of the effect of saline lake water disposalon aquatic macroinvertebrates and water quality wasconducted in the Barwon River, south west Victoria,Australia, in association with toxicity tests. Thedisposal of saline lake water was associated withchanges in macroinvertebrate community structure.Contrary to expectations, increases in electricalconductivity (a measure of salinity) was not the onlywater quality parameter associated with saline waterdisposal. An experiment was conducted where thetoxicity of saline lake water was compared to that ofa prepared solution of the same electricalconductivity. Toxicity was greater in the saline lakewater than the prepared solution. The results suggestthat saline water disposal is impacting onmacroinvertebrate fauna but electrical conductivity isnot the only factor responsible. These results haveconsequences for both management of aquatic resourcesand for monitoring programs which are discussed.     

Concentration of trace metals in sediments and soils from protected lands in south Florida: background levels and risk evaluation

A comprehensive environmental evaluation was completed on 20 metals: two reference metals (Fe, Al) and several minor trace metals (As, Ba, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn) for surface soils and sediments collected from 50 sites in Everglades National Park (ENP), the coastal fringes of Biscayne National Park (BNP), and Big Cypress National Preserve. Samples were prepared by acid digestion (EPA3050) and analyzed by ICP/MS detection (EPA6020). Although no widespread contamination was detected across the two parks and one preserve, there were some specific areas where metal concentrations exceeded Florida’s ecological thresholds, suggesting that some metals were of concern. A screening-level evaluation based on a proposed effect index grouped trace metals by their potential for causing negligible, possible, and probable effects on the biota. For example, Cu in BNP and Cr and Pb in ENP were considered of concern because their adverse effect likelihood to biota was assessed as probable; consequently, these trace metals were selected for further risk characterization. Also, stations were ranked based on a proposed overall contamination index that showed that: site BB10 in BNP and sites E3 and E5 in ENP had the highest scores. The first site was located in a marina in BNP, and the other two sites were along the eastern boundary of ENP adjacent to current or former agricultural lands. An assessment tool for south Florida protected lands was developed for evaluating impacts from on-going Everglades restoration projects and to assist State and Federal agencies with resource management. The tool consists of enrichment plots and statistically derived background concentrations based on soil/sediment data collected from the two national parks and one preserve. Finally, an equally accurate but much simplified approach is offered for developing enrichment plots for other environmental settings.     

Occurrence and distribution of polycyclic aromatic hydrocarbons in surface microlayer and subsurface seawater of Lagos Lagoon,Nigeria

Polycyclic aromatic hydrocarbons (PAHs) in surface microlayer (SML) and subsurface water (SSW) of Lagos Lagoon were investigated using gas chromatography-electron capture detector (GC-ECD) technique to ascertain their occurrence and spatial distribution, origin, enrichment, and carcinogenicity. Total PAH (ΣPAH) concentrations ranged from 9.10 to 16.20 μg L^?1 in the SML and 8.90 to 13.30 μg L^?1 in the SSW. ΣPAH concentrations were relatively higher in the SML than the underlying SSW samples. The enrichment factors (EFs) of ΣPAHs ranged from 0.76 to 1.74 while the EFs of the individual PAHs varied from 0.50 to 2.09. In general, the EFs values calculated in this study were consistent or slightly less than the EFs reported for similar coastal seawater ecosystems. A correlation between the EFs of fluoranthene and pyrene indicated a positive significant value (R?=?0.9828, p?<?0.0001, n?=?6). Source analyses using the phenanthrene/anthracene and fluoranthene/pyrene ratios indicated the dominance of petrogenic-derived PAHs. Furthermore, enhanced concentrations of BaP (strong carcinogenicity) in SML and SSW samples, which resulted in higher EFs, could pose serious ecological and human health risks.     

Joint Impact of Scaling and Hysteresis on NAPL Flow Simulation

The hysteresis of capillary pressure versus saturation (P–S) relation is an important constitutive relation in multiphase flow, since the P–S relation is widely used to predict P–S relations in the simulation of the non-aqueous phase liquids (NAPLs). This work examined the performance of the scaling rule on predicting the P–S relationship and then studied the joint impact of the scaling and hysteresis on the multiphase NAPL flow simulation. Various experimental P–S values of distinct fluid pairs were compared with the scaled P–S curves using the scaling rule. The comparison indicated that the prediction of P–S is more accurate when the water–air P–S curve is used to scale other P–S curves. The joint impact of the scaling and hysteresis on the NAPLs flow simulation was then investigated by numerical simulation studies. The NAPL simulator was used to simulate the outcome of several scenarios based on a system with water–NAPL–air in a hypothetical sand tank. For both gasoline and trichloroethylene, the difference of the injected NAPL volume between no hysteretic and hysteretic simulations over a given time period was the smallest when the water–air P–S curve was used to scale other P–S curves. Simulation results of this study are valuable references for predicting the distribution of NAPLs.     

China's water risk assessment and industrial source analysis based on the localization of WWF water risk assessment tools

The WWF water risk assessment tool is a universal methodology, as the establishment of its indicators fully consider various types of natural and social environments. When this tool is applied to China, a large country with a complex water situation in a period of rapid development, appropriate localization adjustment is necessary to ensure that indicators are generally stable and assessment results are internationally comparable. Based on the localization of WWF water risk assessment tools, this is the first application assessing water risk in China in terms of physical risks, regulatory risks and reputation risks. It explores the sources of China's water risk from industrial sectors and constructs a classification index system according to the degree of water dependence and the level of water pollution. Using the classification index system and relevant data, we find the key industrial sectors, enterprises and production processes to reduce water risk in China's ten major water valleys and offer some effective and practical management suggestions. Due to the large regional differences of water risk-bearing capacity in China, the assessment results should be interpreted in combination with specific national conditions of China and emphasis should be laid on key areas and industries.     

电磁辐射对人体健康的危害及防护

就城市空间电磁环境所带来的负面影响，分析了电磁辐射的来源，探讨了电磁辐射对人体健康的危害及防护措施，对电磁环境管理提出建议。