Influence of lake morphology on water quality

Lakes are seriously affected due to urban pollution. The study of the morphological features of a lake system helps to identify its environmental status. The objective of the present study is to analyse the influence of morphometry on water quality in a lake (Akkulam-Veli Lake, Thiruvananthapuram, Kerala). The morphological features namely mean depth, surface area, volume, shoreline length, shoreline development and index of basin permanence have been evaluated. Correlation analysis has been conducted to determine the relationship between morphological features and water quality. Regression analysis has been conducted to find out the extent of influence of morphometric features on water quality. The study revealed that the lake is less affected by wind-induced wave action due to various reasons. The depth and volume have significant role in the water quality. The nitrogen fixation of blue green algae can be observed from the morphological features. The morphology has greater role in the water quality of a lake system.     

A multi-variate methodology for analyzing pre-existing lake water quality data

Environmental agencies are given the task of monitoring water quality in rivers, lakes, and other bodies of water, for the purpose of comparing the results with regulatory standards. Monitoring follows requirements set by regulations, and data are collected in a systematic way for the intended purpose. Monitoring enables agencies to determine whether water bodies are polluted. Much effort is spent per monitoring event, resulting in hundreds of data points typically used solely for comparison with regulatory standards and then stored for little further use. This paper devises a data analysis methodology that can make use of the pre-existing datasets to extract more useful information on water quality trends, without new sample collection and analysis. In this paper, measured lake water quality data are subjected to statistical analyses including Principal Component Analysis (PCA) to deduce changes in water quality spatially and temporally over several years. It was found that the lake as a whole changed temporally by season, rather than spatially. Storm events caused the greatest shifts in water quality, though the shifts were fairly consistent across sampling stations. This methodology can be applied to similar datasets, especially with the recent emphasis by the U.S. EPA on protection of lakes as water sources. Water quality managers using these techniques may be able to lower their monitoring costs by eliminating redundant water quality parameters found in this analysis.     

The effects of the environment and ecology projects on lake management and water quality

In this study, the characteristics, benefits, and effects of the environment and ecology project, which has been implemented in Turkey for the first time to restore the natural life that has been spoilt and the ecological balance of Lake Bafa located in Great Meander Basin, are searched. Moreover, the water samples taken from the stations that were spotted in the lake have been analyzed for the physical and chemical changes taking place in water quality before and after the project. The water cycle occurring as a result of giving water that was raised in Great Meander River by the Rubber regulator, which is the most important element of the project, through the Serçin inlet and feeder channel; and draining the saline and low-quality water to the river bed of the Great Meander, will improve the water quality, the natural life, and the ecological balance of the lake in time. Thanks to the water given to the lake within the scope of project, the salinity of the lake water decreased from 25,500 to 22,500 mmhos cm^???1. The electrical conductivity, Na^?+?, Mg^?+?2, Ca^?+?2, Cl^???, $\text{CO}_\text{3} ^{-\text{2}}In this study, the characteristics, benefits, and effects of the environment and ecology project, which has been implemented in Turkey for the first time to restore the natural life that has been spoilt and the ecological balance of Lake Bafa located in Great Meander Basin, are searched. Moreover, the water samples taken from the stations that were spotted in the lake have been analyzed for the physical and chemical changes taking place in water quality before and after the project. The water cycle occurring as a result of giving water that was raised in Great Meander River by the Rubber regulator, which is the most important element of the project, through the Ser?in inlet and feeder channel; and draining the saline and low-quality water to the river bed of the Great Meander, will improve the water quality, the natural life, and the ecological balance of the lake in time. Thanks to the water given to the lake within the scope of project, the salinity of the lake water decreased from 25,500 to 22,500 mmhos cm( - 1). The electrical conductivity, Na+, Mg+2, Ca+2, Cl(-), CO3(-2), HCO3(-), and the amount of the organic substances were found as over the appropriate values for fishery. Besides, the decreases in the amounts of NO3(-), HN3(-) and PO4(-3) affect the living beings in the lake negatively. In addition, the measures to take are specified, so that the natural life of the Lake and the ecological balance can renew themselves within a short time.     

Changes of the phytoplankton community as symptoms of deterioration of water quality in a shallow lake

Covering more than 60% of the lake surface, macrophytes determined the taxonomic composition of phytoplankton. We have found numerous indications of ecological deterioration and an increased trophic level year to year: an increased total number of taxa; a significantly increased number of species of Chlorophyta, Bacillariophyceae and Cyanoprokaryota; a decreased number of Chrysophyceae; increased Nygaard index, and high diversity and variability of phytoplankton functional groups. Within 2 years (2002 and 2003) algal biomass doubled: from 3.616 to 7.968 mg l^?1. An increased contribution of Chlorococcales and Cyanoprokaryota indicates progressive eutrophication of the lake. The average size of planktonic algae increased, particularly Cyanoprokaryota, where small-celled decreased dramatically and were replaced by large colonies. Cyanoprokaryota remained the dominant group of phytoplankton after 10 years, and the ecosystem of the lake remained in the turbid state. This group of algae had the average biomass 9.734 mg l^?1, which constituted almost 92% of the total biomass.     

Development of a new risk-based framework to guide investment in water quality monitoring

An innovative framework for optimising investments in water quality monitoring has been developed for use by water and environmental agencies. By utilising historical data, investigating the accuracy of monitoring methods and considering the risk tolerance of the management agency, this new methodology calculates optimum water quality monitoring frequencies for individual water bodies. Such information can be applied to water quality constituents of concern in both engineered and natural water bodies and will guide the investment of monitoring resources. Here we present both the development of the framework itself and a proof of concept by applying it to the occurrence of hazardous cyanobacterial blooms in freshwater lakes. This application to existing data demonstrates the robustness of the approach and the capacity of the framework to optimise the allocation of both monitoring and mitigation resources. When applied to cyanobacterial blooms in the Swan Coastal Plain of Western Australia, we determined that optimising the monitoring regime at individual lakes could greatly alter the overall monitoring schedule for the region, rendering it more risk averse without increasing the amount of monitoring resources required. For water resources with high-density temporal data related to constituents of concern, a similar reduction in risk may be observed by applying the framework.     

Quantifying sample biases of inland lake sampling programs in relation to lake surface area and land use/cover

We quantified potential biases associated with lakes monitored using non-probability based sampling by six state agencies in the USA (Michigan, Wisconsin, Iowa, Ohio, Maine, and New Hampshire). To identify biases, we compared state-monitored lakes to a census population of lakes derived from the National Hydrography Dataset. We then estimated the probability of lakes being sampled using generalized linear mixed models. Our two research questions were: (1) are there systematic differences in lake area and land use/land cover (LULC) surrounding lakes monitored by state agencies when compared to the entire population of lakes? and (2) after controlling for the effects of lake size, does the probability of sampling vary depending on the surrounding LULC features? We examined the biases associated with surrounding LULC because of the established links between LULC and lake water quality. For all states, we found that larger lakes had a higher probability of being sampled compared to smaller lakes. Significant interactions between lake size and LULC prohibit us from drawing conclusions about the main effects of LULC; however, in general lakes that are most likely to be sampled have either high urban use, high agricultural use, high forest cover, or low wetland cover. Our analyses support the assertion that data derived from non-probability-based surveys must be used with caution when attempting to make generalizations to the entire population of interest, and that probability-based surveys are needed to ensure unbiased, accurate estimates of lake status and trends at regional to national scales.     

Fish diversity with relation to water quality of Bhadra River of Western Ghats (INDIA)

Water quality assessment and freshwater fish diversity of Bhadra river, Western Ghats, Karnataka was examined. River water was clear except at one station (BV Site) with rocky and sandy substrate. The mean water quality of study sites were as following, pH 6.98, air temperature 22.66°C, water temperature 20.16°C, dissolved oxygen 8.74 mg/l, total hardness 27 mg/l, alkalinity 48 mg/l (as CaCO₃), conductivity 135.5 mhos/cm, COD (15.16 mg/l), and BOD (3.78 mg/l), respectively. Altogether, 56 species of fish representing 31 genera and 15 families were recorded. The Cyprinid family was dominant in the present study. Various diversity index packages have been used to assess the fish diversity. Fish diversity is also correlated with physicochemical variables.     

Oxygen depletion in relation to water residence times

The relationship between residence time and oxygen saturation was investigated in a mesotidal lagoon in southern Portugal. The system receives no significant freshwater input during the summer months and has a high evaporation rate. These features enable an estimate of residence time from the salinity differences between ocean water entering the system and lagoon water. More than 10,000 GPS referenced measurements of oxygen saturation, temperature and salinity were made during large spring tides in September, 2006. The lowest oxygen saturation ( approximately 44%) was measured in the waters with the highest calculated residence times (7 days). There was a significant linear decrease in the oxygen saturation with increasing residence time of approximately 16% per day. This was similar to the rate measured on a neap tide in August, 2005. The high salinity, low oxygen saturated water was spatially confined to one inner channel, except at high water when this water was pushed into other channels. Although the tides investigated were the largest for several years, the oxygen saturation did not exceed 70% in this inner region. It is proposed that the direct discharge of oxygen consuming effluent, including domestic sewage, into this inner channel is responsible for this persistent oxygen deficit.     

Problems in characterizing the ecological quality of soil in relation to human activities

The soil ecosystem is composed of various groups of organisms which have complex relations. The physical structure and chemical characteristics of the soil provide the boundary conditions. In view of various deteriorating human activities, it is important to find soil quality characteristics with respect to its most important function: the ecological function. An enumeration has been given of chemical, physical and biological soil parameters which are more or less important for soil quality. Several of these parameters are discussed. For use as indicators of deterioration, for a given site, the optimum values of the soil parameters have to be established, as well as acceptable deviations from the optimum, taking into account natural fluctuation. It is concluded that, due to lack of data, such an approach is not possible at this moment. However, it might be possible to identify those soil parameters which should be taken into consideration when evaluating human activities.Paper presented at a Symposium held on 14 and 15 October 1982, in Utrecht, The Netherlands.     

Comparison of different semi-empirical algorithms to estimate chlorophyll-a concentration in inland lake water

Based on in situ water sampling and field spectral measurement from June to September 2004 in Lake Chagan, a comparison of several existing semi-empirical algorithms to determine chlorophyll-a (Chl-a) content was made by applying them to the field spectra and in situ chlorophyll measurements. Results indicated that the first derivative of reflectance was well correlated with Chl-a. The highest correlation between the first derivative and Chl-a was at 680 nm. The two-band model, NIR/red ratio of R_710/670, was also an effective predictor of Chl-a concentration. Since the two-band ratios model is a special case of the three-band model developed recently, three-band model in Lake Chagan showed a higher resolution. The new algorithm named reverse continuum removal relies on the reflectance peak at 700 nm whose shape and position depend strongly upon chlorophyll concentration: The depth and area of the peak above a baseline showed a linear relationship to Chl-a concentration. All of the algorithms mentioned proved to be of value and can be used to predict Chl-a concentration. Best results were obtained by using the algorithms of the first derivative, which yielded R ² around 0.74 and RMSE around 6.39 μg/l. The two-band and three-band algorithms were further applied to MERIS when filed spectral were resampled with regard to their center wavelengths. Both algorithms showed an adequate precision, and the differences on the outcome were small with R ² = 0.70 and 0.71.     

Characterization of microbial communities from coastal waters using microarrays

Molecular methods, including DNA probes, were used to identify and enumerate pathogenic Vibrio species in the Chesapeake Bay; our data indicated that Vibrio vulnificus exhibits seasonal fluctuations in number. Our work included a characterization of total microbial communities from the Bay; development of microarrays that identify and quantify the diversity of those communities; and observation of temporal changes in those communities. To identify members of the microbial community, we amplified the 16S rDNA gene from community DNA isolated from a biofilm sample collected from the Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or more similar to 7 species including two recently described Shewanella species, baltica and frigidimarina, that have not been previously isolated from the Chesapeake. When the genera of bacteria from biofilm after culturing are compared to those detected by subcloning amplified 16S fragments from community DNA, the cultured sample exhibited a strong bias. In oysters collected in February, the most common bacteria were previously unknown. Based on our 16S findings, we are developing microarrays to detect these and other microbial species in these estuarine communities. The microarrays will detect each species using four distinct loci, with the multiple loci serving as an internal control. The accuracy of the microarray will be measured using sentinel species such as Aeromonas species, Escherichia coli, and Vibrio vulnificus. Using microarrays, it should be possible to determine the annual fluctuations of bacterial species (culturable and non-culturable, pathogenic and non-pathogenic). The data may be applied to understanding patterns of environmental change; assessing the health of the Bay; and evaluating the risk of human illness associated with exposure to and ingestion of water and shellfish.     

Assessment of water quality monitoring for the optimal sensor placement in lake Yahuarcocha using pattern recognition techniques and geographical information systems

Pollution and the eutrophication process are increasing in lake Yahuarcocha and constant water quality monitoring is essential for a better understanding of the patterns occurring in this ecosystem. In this study, key sensor locations were determined using spatial and temporal analyses combined with geographical information systems (GIS) to assess the influence of weather features, anthropogenic activities, and other non-point pollution sources. A water quality monitoring network was established to obtain data on 14 physicochemical and microbiological parameters at each of seven sample sites over a period of 13 months. A spatial and temporal statistical approach using pattern recognition techniques, such as cluster analysis (CA) and discriminant analysis (DA), was employed to classify and identify the most important water quality parameters in the lake. The original monitoring network was reduced to four optimal sensor locations based on a fuzzy overlay of the interpolations of concentration variations of the most important parameters.     

Assessing water quality in a tropical lake using biomarkers in zebrafish embryos: developmental toxicity and stress protein responses

In order to achieve a more substantial appraisal of lake water quality, the assessment must not be based only on chemical measurements and analyses of the water itself, but even more so on the impact of existing conditions on aquatic biota. This is possible with the use of biotests or biomarkers, e.g. investigations of the developmental parameters (96-h embryotoxicity evaluate) or of the induction of heat shock proteins (proteotoxicity evaluate). To evaluate the suitability of these tests for environmental screening, fertilized zebrafish eggs were exposed to water samples collected from five sites of varying levels of stress from Laguna Lake, Philippines. Reconstituted water was used as laboratory control while water samples from a highly polluted freshwater source was used as positive control. Developmental parameters were noted and described within 48 and 96 h of exposure. Dilution experiments of the positive control were also done to further assess and compare toxicity potentials of Laguna Lake waters with those originating from a polluted freshwater. After the 96-h exposure, the levels of stress proteins (hsp 70) were determined in embryos from all exposure groups. Results showed 100% mortality in embryos exposed to undiluted positive control (PC) within only 12 h. Increasing dilution levels, however, resulted in lower mortality and lower abnormality rates. No detectable developmental differences were noted among embryos exposed to either the laboratory control or Laguna Lake waters at the end of 96 h, regardless of the source. Very high survival rates and high hatching success rates were observed in embryos exposed to lake waters as well as laboratory control, and the data did not differ significantly among the groups. Likewise, no significant malformations were noted among all developing embryos throughout the exposure period. However, the levels of heat shock proteins in the two sites located closest to Manila, the Philippine capital (Northern West Bay and Central West Bay), showed a pronounced elevation relative to the control, indicating that these stress proteins protect the embryos from the detrimental effects of pollutants in the water. Based on the 96-h early life stage (ELS) test, the water quality of the lake is good for fishery propagation despite the current levels of pollutants in the water. This finding is in accordance with the Class C status (i.e. suitable for fish growth and propagation) as given to the lake by the local environmental agency. On the other hand, data on proteotoxicity showed that the fish are under stress, presumably deriving from pollutants. This calls for a continuous monitoring and improvement of the lake water. The present study indicates that the two biomarker methods are very easy to use, practical, rapid, and sensitive for assessing water quality in a tropical lake and recommends for their incorporation into the future monitoring program of Laguna Lake.     

An assessment of microbial communities associated with surface mining-disturbed overburden

To assess the microbiological changes that occur during the maturation of overburden that has been disturbed by surface mining of coal, a surface mining-disturbed overburden unit in southeastern Ohio, USA was characterized. Overburden from the same unit that had been disturbed for 37 and 16 years were compared to undisturbed soil from the same region. Overburden and soil samples were collected as shallow subsurface cores from each subregion of the mined area (i.e., land 16 years and 37 years post-mining, and unmined land). Chemical and mineralogical characteristics of overburden samples were determined, as were microbial respiration rates. The composition of microbial communities associated with overburden and soil were determined using culture-independent, nucleic acid-based approaches. Chemical and mineralogical evaluation of overburden suggested that weathering of disturbed overburden gave rise to a setting with lower pH and more oxidized chemical constituents. Overburden-associated microbial biomass and respiration rates increased with time after overburden disturbance. Evaluation of 16S rRNA gene libraries that were produced by “next-generation” sequencing technology revealed that recently disturbed overburden contained an abundance of phylotypes attributable to sulfur-oxidizing Limnobacter spp., but with increasing time post-disturbance, overburden-associated microbial communities developed a structure similar to that of undisturbed soil, but retained characteristics of more recently disturbed overburden. Our results indicate that over time, the biogeochemical weathering of disturbed overburden leads to the development of geochemical conditions and microbial communities that approximate those of undisturbed soil, but that this transition is incomplete after 37 years of overburden maturation.     

The effects of season and sand mining activities on thermal regime and water quality in a large shallow tropical lake

Thermal structure and water quality in a large and shallow lake in Malaysia were studied between January 2012 and June 2013 in order to understand variations in relation to water level fluctuations and in-stream mining activities. Environmental variables, namely temperature, turbidity, dissolved oxygen, pH, electrical conductivity, chlorophyll-A and transparency, were measured using a multi-parameter probe and a Secchi disk. Measurements of environmental variables were performed at 0.1 m intervals from the surface to the bottom of the lake during the dry and wet seasons. High water level and strong solar radiation increased temperature stratification. River discharges during the wet season, and unsustainable sand mining activities led to an increased turbidity exceeding 100 NTU, and reduced transparency, which changed the temperature variation and subsequently altered the water quality pattern.     

Development and sensitivity analysis of a global drinking water quality index

The UNEP GEMS/Water Programme is the leading international agency responsible for the development of water quality indicators and maintains the only global database of water quality for inland waters (GEMStat). The protection of source water quality for domestic use (drinking water, abstraction etc) was identified by GEMS/Water as a priority for assessment. A composite index was developed to assess source water quality across a range of inland water types, globally, and over time. The approach for development was three-fold: (1) Select guidelines from the World Health Organisation that are appropriate in assessing global water quality for human health, (2) Select variables from GEMStat that have an appropriate guideline and reasonable global coverage, and (3) determine, on an annual basis, an overall index rating for each station using the water quality index equation endorsed by the Canadian Council of Ministers of the Environment. The index allowed measurements of the frequency and extent to which variables exceeded their respective WHO guidelines, at each individual monitoring station included within GEMStat, allowing both spatial and temporal assessment of global water quality. Development of the index was followed by preliminary sensitivity analysis and verification of the index against real water quality data.     

Assessment of water quality along a recreational section of the Damour River in Lebanon using the water quality index

Considering that water is becoming progressively scarce, monitoring water quality of rivers is a subject of ongoing concern and research. It is very intricate to accurately express water quality as water quantity due to the various variables influencing it. A water quality index which integrates several variables in a specific value may be used as a management tool in water quality assessment. Moreover, this index may facilitate communication with the public and decision makers. The main objectives of this research project are to evaluate the water quality index along a recreational section of a relatively small Mediterranean river in Southern Lebanon and to characterize the spatial and temporal variability. Accordingly, an assessment was conducted at the end of the dry season for a period of 5 years from 2005 to 2009. The estimated water quality index classified the average water quality over a 5-year period at the various sites as good. Results revealed that water quality of the Damour River is generally affected by the anthropogenic activities taking place along its watershed. The best quality was found in the upper sites and the worst at the estuary. The presence of fecal coliform bacteria in very high levels may indicate potential health risks to swimmers. This study can be used to support the evaluation of management, regulatory, and monitoring decisions.