M. Jayaprakash

Assessment of Water Quality Using Chemometric Tools: A Case Study of River Cooum, South India

Multivariate statistical techniques were applied to identify and assess the quality of river water. Thirty samples were collected from the River Cooum, and basic chemical parameters—such as pH, effect concentration, total dissolved solids, major cations, anions, nutrients, and trace metals—were evaluated. To evaluate chemical variation and seasonal effect on the variables, analysis of variance and box-and-whisker plots were performed. Cluster analysis was applied, and pre-monsoon and post-monsoon major and minor clusters were classified. The relations among the stations were highlighted by cluster analysis, which were represented by dendograms to categorize different levels of contamination. Cluster analysis clearly grouped stations into polluted and unpolluted regions. The analysis classified the upper part of the river course into one unpolluted cluster; the middle and lower parts of the river clustered together, reflecting the presence of pollution. Factor analysis revealed that water quality is strongly affected by anthropogenic activities, rock–water interaction, and saline water intrusion. Seasonal variations in water chemistry were clearly highlighted by both cluster and factor analysis. Factor-score diagrams were used successfully to delineate the stations under study by the contributing factors, and seasonal effects on the sample stations were identified and evaluated. These statistical approaches and results yielded useful information about water quality and can lead to better water resource management.

Groundwater Quality Assessment Using Chemometric Analysis in the Adyar River, South India

A multivariate statistical technique has been used to assess the factors responsible for the chemical composition of the groundwater near the highly polluted Adyar River. Basic chemical parameters of the groundwater have been pooled together for evaluating and interpreting a few empirical factors controlling the chemical nature of the water. Twenty-three groundwater samples were collected in the vicinity of the Adyar River. Box-whisker plots were drawn to evaluate the chemical variation and the seasonal effect on the variables. R-mode factor analysis and cluster analysis were applied to the geochemical parameters of the water to identify the factors affecting the chemical composition of the groundwater. Dendograms of both the seasons gives two major clusters reflecting the groups of polluted and unpolluted stations. The other two minor clusters and the movement of stations from one cluster to another clearly bring out the seasonal variation in the chemical composition of the groundwater. The results of the R-mode factor analysis reveal that the groundwater chemistry of the study area reflects the influence of anthropogenic activities, rock-water interactions, saline water intrusion into the river water, and subsequent percolation into the groundwater. The complex geochemical data of the groundwater were interpreted by reducing them to seven major factors, and the seasonal variation in the chemistry of water was clearly brought out by these factors. The higher concentration of heavy metals such as Fe and Cr is attributed to the rock-water interaction and effluents from industries such as tanning, chrome-plating, and dyeing. In the urban area, the Pb concentration is high due to industrial as well as urban runoff of the atmospheric deposition from automobile pollution. Factor score analysis was used successfully to delineate the stations under study with the contributing factors, and the seasonal effect on the sample stations was identified and evaluated.

Identification and evaluation of hydrogeochemical processes on river Cooum, South India

The salient features of the river water chemistry and the seasonal variations on the individual chemical parameter were evaluated and characterized. The order of abundance of the ions in the water is determined for both seasons. The contribution of chemical weathering to the water chemistry has been determined using the (Ca2+ + Mg2+)/(Na+ + K+) ratio, ternary, and Gibb’s diagrams. The results show that the chemical composition of river water during premonsoon is controlled mainly by evaporation–crystallization, while in the postmonsoon, the rock–water interaction dominates. The unique characteristic of the river water is the linear relationship among the principal ions. Hydrochemical characteristics of ions in the water were studied using 1:1 equiline diagrams. The nature of the water samples was determined using the piper diagram. The influence of trace metals on the chemical composition and the quality of the river water in the study area has been assessed using Wilcox and US Salinity Laboratory diagrams.

Assessment of trace element accumulation in surface sediments off Chennai coast after a major flood event

The present study was conducted to assess the trace element concentration in marine surface sediments after major flood event of Chennai metropolis, India. Thirty surface samples were collected from off Chennai coast. Trace elements, organic matter, CaCO3, sand-silt-clay and C/N ratios were studied to understand the accumulation dynamics on sediments. The elemental concentration, calcium carbonate and OM distribution suggest that they are derived from urban runoff and transported through Adyar and Cooum Rivers. The enrichment factor reveals that the sediments are enriched by Pb, Cu, Zn, Cr, Co, Ni followed by Fe. The observed Igeo value shows that the samples are contaminated by Pb, Cu and Zn. The elemental concentration of the surface sediments is low when compared to other coastal region except Pb. The elevated level of Pb in the surface sediments is probably due to migration of contaminated urban soil from industrial and transportation sectors into marine environment.

Application of chemometric analysis for identifying pollution sources: a case study on the River Adyar, India

The various factors responsible for the chemical budget and pollution of river water have been evaluated and characterised using various statistical tools. The potential sources of pollution that alter the chemical composition of River Adyar water have been identified and quantified. Thirty-three samples were collected from the River Adyar and basic chemical parameters and heavy metals were interpreted by the systematic application of statistical techniques. The relationships among the various ions were examined and the sources of origin were evaluated using correlation studies. An R-mode factor analysis revealed that the chemistry of the river water largely depends on anthropogenic activities, rock–water interaction and saline water intrusion. A cluster analysis was applied and the major and minor clusters for pre-monsoon and post-monsoon seasons were classified. This classification was found to be in line with the results of the R-mode factor analysis. Seasonal variation in the chemistry and pollution level of the river water was clearly indicated by both cluster and factor analyses. Factor scores, which give vital information on the variation of the factors by station, were successfully applied. The contributing factors and any seasonal effect on the stations were evaluated and interpreted.

Geochemical assessment of heavy metals pollution in surface sediments of Vellar and Coleroon estuaries, southeast coast of India.

Surface sediments were collected from Vellar and Coleroon estuaries for determine sediment texture, calcium carbonate, organic matter and heavy metals. Pollution indices such as pollution load index (PLI), contamination factor (CF), enrichment factor (EF) and geo-accumulation index (Igeo) were done for this study to know the level of heavy metals pollution in the estuarine ecosystem. Pearson correlation matrix and factor were used to assess the relationship and source of heavy metals in the estuarine sediments. The results of PLI values reveal that the study area was polluted by all the heavy metals. The calculated values of CF and Igeo followed the decreasing order Cu>Ni>Pb>Co>Cr>Zn>Mn>Fe and illustrate that Cu, Ni and Pb are contaminated due to anthropogenic sources in both estuaries. Correlation and factor analysis suggest that FeMn oxyhydroxides, organic matter and fine particles are responsible for high concentration of heavy metals.

Geochemical study of core sediments from Ennore Creek, North of Chennai, Tamil Nadu, India

The present study was carried out to investigate the down core variation of trace metal concentration in core samples of the study area. Six core samples were collected to assess the trace metal distribution in Ennore. All the core samples are dominated by coarse fraction of the sediments. In general, all the core samples have higher concentration of OM and are depleted in CaCO3 concentration. The highly inconsistent Mn concentration in surface sediments of the present study upholds the idea that oxyhydroxide flocs of Mn are transported laterally during saline bottom water inflow and deposited in quiescent parts of the estuary. Although the concentrations of Cr and Ni are both relatively higher, the influence on the former is anthropogenic, while that on the latter is more detrital. EF places Ennore under minimal to significant contamination of Cr and Cu. According to Pollution Load Index calculations, Ennore shows low-to-moderate degree of contamination.

Water quality of the Uppanar estuary, Southern India: Implications on the level of dissolved nutrients and trace elements

The current status of the water quality in terms of nutrients and trace elements were assessed in the Uppanar river estuary, Southern India. Twenty-five sampling stations were monitored in the study area, which is dominated by anthropogenic activities such as agriculture, settlements and fishing harbour in the downstream. Whereas, the upstream and midstream is dominated by barren lands and industrial hub respectively. Nutrients and trace elements such as nitrate, phosphate, iron and lead exceed the permissible limit of WHO drinking water guidelines. The water quality index derived from WHO permissible limits reveal that most of the samples fall under fair to good category. The marginal to fair water quality is noticed in the midstream to downstream region, where anthropogenic activities are high. The multivariate statistical analysis divulges that the overall water quality is controlled by two major sources such as natural weathering of soil/bedrock and agricultural and industrial activities.

Speciation technique for the risk assessment of trace metals in the bed sediments of River Cooum, South India

Abstract Speciation of sediment samples yields valuable information on the nature of the metals bound to the sediments. Thirty samples of River Cooum sediment were collected during two seasons and a fractionation study was carried out. The middle and lower parts of the Cooum River flow largely through urbanized areas and are grossly polluted by industrial and domestic wastes. To ascertain the extent of heavy metal pollution in the bed sediments of the river, total metal content and speciation were evaluated. The summation of the metal recoveries in the sequential extractions was found to be within ± 10 % of the total metal content. The mobility factor was evaluated which represents the exchangeable and carbonate fractions in the sediments. Risk Assessment Code (RAC) was estimated and the results reveal the extent of risk associated with the heavy metals in the sediments in various stations. The results of the fractionation show that Ni and Pb fall in the high risk category in certain stations in the middle and lower parts of the river. Except for Cr and Fe, all other heavy metals studied show medium risk with regard to RAC. The effect of the monsoon on the concentrations of the metals in various fractions has been evaluated and the significance of seasonal effect was determined using Student’s t-test.

Seasonal variations and environmental risk assessment of trace elements in the sediments of Uppanar River estuary, southern India

Twenty four surface sediments were gathered from the Uppanar river estuary, southern India to evaluate the trace element contamination risk in the sediments. The circulation of organic matter and calcium carbonate were controlled by algal blooms and shell fragments. Moreover, the concentrations of iron and manganese in the estuarine sediments were possibly contributed by riverine sources and geogenic processes. The geoaccumulation index, enrichment factor and contamination factor reveals that the sediments were contaminated by copper and chromium. The pollution load index recommends that the estuarine sediments have the risk of pollution. The sediment pollution index highlights that the majority of the sediments are low polluted sediments. The potential ecological risk index discloses that the Uppanar river estuary is under moderate risk. The statistical analysis reveals that the organic matter content is managed by fine fractions and the majority of the trace elements are associated with each other having similar origin.