Anti-barnacle biofouling coatings for the protection of marine vessels: synthesis and progress

Environmental Science and Pollution Research - Marine biofouling has gnawed both mobile and non-mobile marine structures since time immemorial, leading to the deterioration of designed operational...     

Application of Water Quality Indices and Dissolved Oxygen as Indicators for River Water Classification and Urban Impact Assessment

The usefulness of water quality indices, as the indicators of water pollution, for assessment of spatial-temporal changes and classification of river water qualities was verified. Four water quality indices were investigated: WQI (considering 18 water quality parameters), WQI(min) and WQI(m) (considering five water quality parameters: temperature, pH, DO, EC and TSS) and WQI(DO) (considering a single parameter, DO). The water quality indices WQI(min), WQI(m) and WQI(DO) could be of particular interest for the developing countries because of the minimum analytical cost involved. As a case study, water quality indices were used to evaluate spatial and temporal changes of the water quality in the Bagmati river basin (Nepal) for the study period 1999-2003. The results allowed us to determine the serious negative effects of the city urban activity on the river water quality. In the studied section of the river, the water quality index (WQI) was 71 units (classified as good) at the entry station and 47.6 units (classified as bad) at the outlet station. For the studied period, a significant decrease in water quality (mean WQI decrease = 11.6%, p = 0.042) was observed in the rural areas. A comparative analysis revealed that the urban water quality was significantly bad as compared with rural. The analysis enabled to classify the water quality stations into three groups: good water quality, medium water quality and bad water quality. WQI(min) resulted in overestimation of the water quality but with similar trend as with WQI and is useful for the periodic routine monitoring program. The correlation of WQI with WQI(min) and DO resulted two new indices WQI(m) and WQI(DO), respectively. The classification of waters based on WQI(m) and WQI(DO) coincided in 90 and 93% of the samples, respectively.     

Spatial–temporal variation and comparative assessment of water qualities of urban river system: a case study of the river Bagmati (Nepal)

The study presents the assessment of variation of water qualities, classification of monitoring networks and detection of pollution sources along the Bagmati River and its tributaries in the Kathmandu valley of Nepal. Seventeen stations, monitored for 23 physical and chemical parameters in pre-monsoon, monsoon, post-monsoon and winter seasons, during the period 1999-2003, were selected for the purpose of this study. The study revealed that the upstream river water qualities in the rural areas were increasingly affected from human sewage and chemical fertilizers. In downstream urban areas, the river was heavily polluted with untreated municipal sewage. The contribution of industries to pollute the river was minimal. The higher ratio of COD to BOD (3.74 in the rural and 2.06 in the urban) confirmed the increased industrial activities in the rural areas. An increasing trend of nitrate was found in the rural areas. In the urban areas, increasing trend of phosphorus was detected. The water quality measurement in the study period showed that DO was below 4 mg/l and BOD, COD, TIN, TP and TSS above 39.1, 59.2, 10.1, 0.84 and 199 mg/l, respectively, in the urban areas. In the rural areas, DO was above 6.2 mg/l and BOD, COD, TIN, TP and TSS below 15.9, 31, 5.24, 0.41 and 134.5 mg/l, respectively. The analysis for data from 1988 to 2003 at a key station in the river revealed that BOD was increasing at a rate of 1.8 mg/l in the Bagmati River. A comparative study for the water quality variables in the urban areas showed that the main river and its tributaries were equally polluted. The other comparison showed the urban water qualities were significantly poor as compared with rural. The cluster analysis detected three distinct monitoring groups: (1) low water pollution region, (2) medium water pollution region, (3) heavy water pollution region. For rapid assessment of water qualities using the representative sites could serve to optimize cost and time without loosing any significance of the outcome. The factor analysis revealed distinct groups of sources and pollutions (organics, nutrients, solutes and physicochemical).     

Beyond Experimentation: Emerging Issues in the Institutionalization of Joint Forest Management in India

/ During the last decade, a major initiative for community involvement in the management of state forest lands was started in India in the form of Joint Forest Management (JFM) programs. Despite the progress and positive impacts, the JFM program is still in the experimental phase. Latent conflicts related to caste, class, and gender issues are threatening JFM institutions at the village level. The Forest Department is also facing a number of internal conflicts as it tries to adjust to its new role under JFM. Some thoughtful and creative attempts have been made to resolve these conflicts. However, a much more concerted effort is required along with creation of suitable mechanisms at local, state, and national levels to discuss and resolve present and future conflicts.     

Metal- and ionic liquid-based photocatalysts for biodiesel production: a review

Environmental Chemistry Letters - Diminishing petroleum reserves, increasing carbon emissions, and the growing demand for fuels are calling for alternative fuels. Global diesel consumption...     

Impact of raking and bioturbation-mediated ecological manipulation on sediment–water phosphorus diagenesis: a mesocosm study supported with radioactive signature

The study examined the impact of raking and fish bioturbation on modulating phosphorus (P) concentrations in the water and sediment under different trophic conditions. An outdoor experiment was set to monitor physicochemical and microbiological parameters of water and sediment influencing P diagenesis. A pilot study with radioactive ³²P was also performed under the agency of raking and bacteria (Bacillus sp.). Raking was more effective in release of P under unfertilized conditions by significantly enhancing orthophosphate (35%) and soluble reactive phosphate (31.8%) over respective controls. Bioturbation increased total and available P in sediments significantly as compared to control. The rates of increase were higher in the unfertilized conditions (17.6–28.4% for total P and 12.2 to 23.2% for available P) than the fertilized ones (6.5–12.4% for total P and 9.1 to 15% for available P). The combined effects of raking and bioturbation on orthophosphate and soluble reactive phosphate were also stronger under unfertilized state (54.5 and 81.8%) than fertilized ones (50 and 70%). The tracer signature showed that coupled action of introduced bacteria and repeated raking resulted in 59.2, 23 and 16% higher counts of radioactive P than the treatments receiving raking once, repeated raking and bacteria inoculation, respectively. Raking alone or in sync with bioturbation exerted pronounced impact on P diagenesis through induction of coupled mineralization and nutrient release. It has significant implication for performing regular raking of fish-farm sediments and manipulation of bottom-grazing fish to regulate mineralization of organic matter and release of obnoxious gases from the system. Further, they synergistically can enhance the buffering capacity against organic overload and help to maintain aquatic ecosystem health.

     

CONTROLLING GROUND WATER DEGRADATION IN THE TULARE LAKE BASIN1

ABSTRACT This study examined the feasibility of extending the Accelerated Salt Transport (ASTRAN) method of groud water quality control to a complex, closed basin which is experiencing ground water quality degradation from irrigated agriculture (e.g., the Tulare Lake Basin in the Southern portion of the California Central Valley). A linear programming model was constructed and parametric analysis conducted which produced results with a “general appraisal” (or “level B”) degree of accuracy. The study concluded that a drainage water export drain is required in order to implement a long-term solution but that ground water degradation can be mitigated by a combination of the ASTRAN method and other measures even with existing entitlements and legal constraints.     

Assessment of Air Quality After the Implementation of Compressed Natural Gas (CNG) as Fuel in Public Transport in Delhi, India

Public transport in Delhi was amended by the Supreme Court of India to use Compressed Natural Gas (CNG) instead of diesel or petrol. After the implementation of CNG since April 2001, Delhi has the highest fraction of CNG-run public vehicles in the world and most of them were introduced within 20 months. In the present study, the concentrations of various criteria air pollutants (SPM, PM₁₀, CO, SO₂ and NO_x) and organic pollutants such as benzene, toluene, xylene (BTX) and polycyclic aromatic hydrocarbons (PAHs) were assessed before and after the implementation of CNG. A decreasing trend was found for PAHs, SO₂ and CO concentrations, while the NO_x level was increased in comparison to those before the implementation of CNG. Further, SPM, PM₁₀, and BTX concentrations showed no significant change after the implementation of CNG. However, the BTX concentration demonstrated a clear relation with the benzene content of gasoline. In addition to the impact of the introduction of CNG the daily variation in PAHs levels was also studied and the PAHs concentrations were observed to be relatively high between 10 pm to 6 am, which gives a proof of a relation with the limited day entry and movement of heavy vehicles in Delhi.     

A Review of Public Domain Water Quality Models for Simulating Dissolved Oxygen in Rivers and Streams

The review discusses six major public domain water quality models currently available for rivers and streams. These major models, which differ greatly in terms of processes they represent, data inputs requirements, assumptions, modeling capability, their strengths and weaknesses, could yield useful results if appropriately selected for the desired purposes. The public domain models, which are most suitable for simulating dissolved oxygen along rivers and streams, chosen in this review are simulation catchment (SIMCAT), temporal overall model for catchments (TOMCAT), QUAL2Kw, QUAL2EU, water quality analysis simulation program (WASP7), and quality simulation along rivers (QUASAR). Each of these models is described based on a consistent set of criteria-conceptualization, processes, input data, model capability, limitations, model strengths, and its application. The results revealed that SIMCAT and TOMCAT are over-simplistic but useful to quickly assess impact of point sources. The QUAL2Kw has provision for conversion of algal death to carbonaceous biochemical oxygen demand (CBOD) and thus more appropriate than QUAL2EU, where macrophytes play an important interaction. The extensive requirement of data in WASP7 and QUASAR is difficult to justify the time and costs required to set up these complex models. Thus, a single model could not serve all wide range of functionalities required. The choice of a model depends upon availability of time, financial cost and a specific application. This review may help to choose appropriate model for a particular water quality problem.