Source discrimination of heavy metals in sediment and water of To Lich River in Hanoi City using multivariate statistical approaches

The concentrations of Mn, Fe, Ni, Cr, Cu, Pb, Zn, As, and Cd were determined to evaluate the level of contamination of To Lich River in Hanoi City. All metal concentrations in 0–10-cm water samples, except Mn, were lower than the maximum permitted concentration for irrigation water standard. Meanwhile, concentrations of As, Cd, and Zn in 0–30-cm sediments were likely to have adverse effects on agriculture and aquatic life. Sediment pollution assessment was undertaken using enrichment factor and geoaccumulation index (I _geo). The I _geo results indicated that the sediment was not polluted with Cr, Mn, Fe, and Ni, and the pollution level increased in the order of Cu < Pb < Zn < As < Cd. Meanwhile, significant enrichment was shown for Cd, As, Zn, and Pb. Cluster and principal component analyses suggest that As and Mn in sediment were derived from both lithogenic and anthropogenic sources, while Cu, Pb, Zn, Cr, Cd, and Ni originated from anthropogenic sources such as vehicular fumes for Pb and metallic discharge from industrial sources and fertilizer application for other metals.     

Assessment of heavy metal levels in sediment samples of Kapulukaya Dam Lake (Kirikkale) and lower catchment area

In this study, the concentrations of 13 elements (Al, Fe, Mn, Cr, Ni, Zn, Co, As, Pb, Cu, Mo, Hg, and Cd) were determined in the sediments of three different sites in the Kapulukaya Dam Lake between May 2007 and November 2008. They ranged from 1.47 to 4.64 for Al, 0.92 to 3.48 for Fe (in percent), 326.60 to 1053.00 for Mn, 98.00 to 1,116.00 for Cr, 24.70 to 127.10 for Ni, 14.80 to 124.20 for Zn, 11.0 to 43.20 for Co, 5.00 to 29.30 for Cu, 9.10 to 69.70 for As, 8.60 to 34.00 for Pb, 2.50 to 5.20 for Mo, 1.00 to 1.60 for Hg, and 0.50 to1.80 for Cd in microgram per gram dry weight sediment. The contamination degree of the sediment was assessed on the basis of enrichment factor and corresponding sediment quality guideline. The calculated enrichment factors (EF, measured metal vs. background concentrations) indicated that the effect of man-made activities on the occurrence of concentrations could be accounted for the majority of heavy metals namely Mn, As, Ni, Cu, Zn, Cr, Co, Mo, and Cd, whereas such affect was not detected for Hg and Pb. The maximum values of the EF were represented by As, minimum values by Hg at all sites. Mean EF values were 36.60 and 0.70 for As and Hg, respectively. This study has clearly assessed a certain level of heavy metal pollution in the region, based particularly on the findings from sediment.     

Heavy metal assessment using geochemical and statistical tools in the surface sediments of Vembanad Lake, Southwest Coast of India

The geochemical distribution and enrichment of ten heavy metals in the surface sediments of Vembanad Lake, southwest coast of India was evaluated. Sediment samples from 47 stations in the Lake were collected during dry and wet seasons in 2008 and examined for heavy metal content (Al, Fe, Mn, Cr, Zn, Ni, Pb, Cu, Co, Cd), organic carbon, and sediment texture. Statistically significant spatial variation was observed among all sediment variables, but negligible significant seasonal variation was observed. Correlation analysis showed that the metal content of sediments was mainly regulated by organic carbon, Fe oxy-hydroxides, and grain size. Principal component analysis was used to reduce the 14 sediment variables into three factors that reveal distinct origins or accumulation mechanisms controlling the chemical composition in the study area. Pollution intensity of the Vembanad Lake was measured using the enrichment factor and the pollution load index. Severe and moderately severe enrichment of Cd and Zn in the north estuary with minor enrichment of Pb and Cr were observed, which reflects the intensity of the anthropogenic inputs related to industrial discharge into this system. The results of pollution load index reveal that the sediment was heavily polluted in northern arm and moderately polluted in the extreme end and port region of the southern arm of the lake. A comparison with sediment quality guideline quotient was also made, indicating that there may be some ecotoxicological risk to benthic organisms in these sediments.     

Distribution and Statistical Analysis of Leachable and Total Heavy Metals in the Sediments of the Suez Gulf

The concentrations of nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the labile and total fractions of muddy and sandy sediment samples collected from twelve sites in Suez Gulf during April 1999 were studied to evaluate the pollution status of the Suez Gulf. The enrichment factors (EF) for each element were calculated. There are extremely high concentrations of Cd, Ni, Pb and slightly concentration of Cr and Cu in both muddy and sandy sediments. The concentration of Zn was moderately high and can be considered as seriously contaminate Metal pollution index (MPI) shows high values ranged between 46 to 156 and 40 to 232 for both sandy and muddy sediments, respectively. Concentrations of heavy metals were normalized against iron for total fraction in both of sandy and muddy sediments. Principal component analysis (PCA) was studied on the data matrix obtained and represented three-factor model explaining 92.22% for labile and 88.82% for total fractions of muddy sediment. The main source of contamination is the offshore oil fields and industrial wastes. This is largely a result of ineffective and inefficient operation equipment, illegal discharge of dirty ballast water from tankers and lack of supervision and prosecution of offenders.     

Total and Leachable Heavy Metals in Muddy and Sandy Sediments of Egyptian Coast Along Mediterranean Sea

The assessment of marine pollution due to metals was made for surficial sediments sampled from 20 sites along Mediterranean coast of Egypt. The samples were dried, acid digested and analyzed for leachable and total heavy metal contents (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) by flame atomic absorption spectrophotometer (air–acetylene) with deuterium background correction. Evaluation of the heavy metals pollution status was carried out using enrichment factors (EFs), the effect range-low (ERL) and the effect range-median (ERM). The study showed high concentrations of Cd, Co, Pb, Ni and moderate concentrations of Cr, Cu and Mn were contaminated in the sediments of studied sites. The results of Spearman correlation, factor and cluster analysis of the heavy metals analyzed in the collected sediment were discussed. The main source of contamination is the offshore oil field and industrial wastes, which arise due to the ineffective and inefficient operation equipments, illegal discharge and lack of supervision and prosecution of offenders.     

Assessment of heavy metal contamination in Candarli Gulf sediment, Eastern Aegean Sea

Concentrations of selected heavy metals (Fe, Mn, Ni, Cu, Zn, Pb, Hg, Cr, Al, and As) in surface sediments from 18 stations in the Candarli Gulf were studied in order to understand current metal contamination due to urbanization and economic development in Candarli region, Turkey. The sediment samples were collected by box corer in Candarli Gulf in 2009 to assess heavy metal pollution. Heavy metal concentrations in surface sediment varied from 1.62% to 3.60% for Fe, 0.38?C2.53% for Al, 173?C1,423 for Mn, 8?C100 for Ni, 3?C46 for Cu, 55?C119 for Zn, 16?C138 for Pb, 0.2?C6.3 for Hg, 16?C71 for Cr, and 11?C37 mg kg^???1 for As. This study showed that the concentrations of Mn, Ni, Zn, Pb, Hg, and Cr in the surface sediment layers were elevated when compared with the subsurface layers. Both metal enrichment and contamination factors show that Hg, Zn, and Pb contamination exists in the entire study area and contamination of other metals is also present in some locations depending on the sources.     

Assessment of seasonal and spatial variations of physicochemical parameters and trace elements along a heavily polluted effluent-dominated stream

This study focuses on a heavily polluted effluent-dominated stream that passes through an industrialized region near Izmir, Turkey. The intermittent creek receives domestic and industrial discharges of Kemalpa?a District Center and its neighborhoods and more than 180 factories of the organized industrial zone. A monitoring campaign was conducted on the creek and samples were taken in two different seasons with distinct hydrological characteristics from 20 stations along the creek to quantify the quality status of water and sediment columns. A number of physicochemical parameters, heavy metals, and trace elements were measured by field and laboratory techniques to assess the status of creek’s water and sediment quality. The spatial and temporal variations were determined, and statistical tools were used to conduct an environmental forensic overview along the creek. A geo-accumulation index and a modified heavy metal pollution index were calculated to cumulatively assess the quality of sediment and water columns, respectively. The results revealed that the creek was under significant pollution load from the industrial zone where metal processing, food and beverage production, marble and natural stone manufacturing, and paper production are made. In particular, elements such as Co, Cu, Cd, Mn, Ni, Pb, Zn, and Zr were found to be above the surface water quality standard values. Similarly, B, Cr, Ni, Cu, Zn, and Sn were determined to be in extreme levels in the sediment column with values exceeding the probable effect concentrations.     

Metal pollution records in core sediments of some Red Sea coastal areas, Kingdom of Saudi Arabia

In the last three decades, the industrial and human activities in the coastal area of Saudi Arabia have increased dramatically and resulted in the continuous invasion of different types of pollutants including heavy metals. Seven sediment cores were collected from three major industrialized areas; Jeddah, Rabigh and Yanbu, along the coast of Saudi Arabia to determine the spatial and temporal distribution of metals and to assess the magnitude of pollution and their potential biological effects. Sediments were analyzed for texture, calcium carbonate contents, organic matter and metals (Al, Fe, Mn, Cd, Cr, Cu, Ni, Pb and Zn). Some metals like, Cr, Mn, Ni and Zn, were enriched in the upper 15 cm of core samples (recent deposition of sediments). Cadmium concentrations showed high fluctuations with depth and reverse pattern to that for Al, Fe and Mn which indicated land based sources of this element to the studied areas. Elevated concentrations of lead were recorded in the bottom layers of cores in Jeddah that indicated the most dramatic increase in usage of gasoline in early 1970s. The calculated contamination factors (CF's) were found in the following sequences: Cd > Pb > Ni > Cu > Zn > Cr > Mn for all studied areas. Results of Pollution Load Index (PLI) revealed that Jeddah is the most polluted area, followed by Rabigh while Yanbu is the least contaminated area. Except for Ni, the concentrations of most metals in the majority of sediment samples were believed to be safe for living organisms. As no data were available on the concentration of metals in core sediments in the coastal area of Saudi Arabia, the results of this study would serve as a baseline against which future anthropogenic effects can be assessed.     

Ecological risk assessment of heavy metals in surface sediments of northern littoral zone of Lake Çıldır,Ardahan, Turkey

In this paper, the heavy metal levels (Cu, Pb, Zn, Ni, Mn, Fe, As, Cd, Cr, Hg), organic carbon, and chlorophyll degradation products were studied to prove their ecological effects in Lake Ç?ld?r, where fossil fuels are used as an energy source in the studied area for most of the year, and domestic waste from settlements is discharged directly into the lake. Sediment samples were collected from six sites on the northern shore of Ç?ld?r Lake, Turkey in November 2012. Enrichment (EF) and contamination factor (CF) values were determined, and Pollution Load (PLI) and Potential Ecological Risk (PER) indices were calculated. Average concentrations of heavy metals in the sediments were, in descending order, Fe?>?Mn?>?Zn?>?Ni?>?Cr?>?Cu?>?Pb?>?As?>?Cd?>?Hg, respectively. According to mean values, the source of these elements may be considered natural due to lack of enrichment in Cu, Pb, Zn, Ni, and Cr in the sediment samples. Regarding enrichment of As, Cd, Mn, and Hg, the highest EF belongs to Hg. PLI and PER values indicate there are moderate ecological risk in the lake.     

Groundwater environmental capacity and its evaluation index

At present, anthropogenic contribution of heavy metals far exceeds natural input in some aquatic sediment, but the proportions are difficult to differentiate due to the changes in sediment characters. In this paper, the metal (Al, Fe, K, Mg, Ca, Cr, Cu, Ni, and Zn) concentrations, grain size, and total organic carbon (TOC) content in the surface and core sediments of Nansihu Lake Catchment (the open lake and six inflow rivers) were determined. The chemical speciations of the metals (Al, Fe, Cr, Cu, Ni, and Zn) in the surface sediments were also analyzed. Approaches of factor analysis, normalized enrichment factor (EF) and the new non-residual fractions enrichment factor (K_NRF) were used to differentiate the sources of the metals in the sediments, from detrital clastic debris or anthropogenic input, and to quantify the anthropogenic contamination. The results indicate that natural processes were more dominant in concentrating the metals in the surface and core sediments of the open lake. High concentration of Ca and deficiency of other metals in the upper layers of the sediment core were attributed to the input of carbonate minerals in the catchment with increasing human activities since 1980s. High TOC content magnified the deficiency of the metals. Nevertheless, the EF and K_NRF both reveal moderate to significant anthropogenic contamination of Cr, Cu, Ni, and Zn in the surface sediments of Laoyun River and the estuary and Cr in the surface sediments of Baima River. The proportion of non-residual fractions (acid soluble, reducible, and oxidizable fractions) of Cr, Cu, Ni, and Zn in the contaminated sediments increased to 37–99% from the background levels less than 30%.     

Assessment of heavy metal concentration in the Khoshk River water and sediment, Shiraz, Southwest Iran

Heavy metal contents and contamination characteristics of the water and sediment of the Khoshk River, Shiraz, Southwest Iran were investigated. The abundance of heavy metals decreases as Zn > Mn > Cr > Ni >Pb > Cu > Cd in water samples and Mn > Cr > Pb > Ni > Zn > Cu > Cd in sediments, respectively. Based on the enrichment factor and geoaccumulation index values, sediments were loaded with Cr, Zn, Pb, Cu, and Cd. Pearson correlation matrix as well as cluster and principal components analyses and analysis of variance were implemented on data from sampling sites. Based on the locations of sampling sites in clusters and variable concentrations at these stations, it was concluded that municipal, industrial, and domestic discharges in the Shiraz urban area strongly affected heavy metals concentrations in the Khoshk River water and sediment. Results obtained from principal components analysis of sediment samples showed that the high concentration of Ni was mainly from natural origin, related to the composition of parent rocks, while the elevated values of Cr, Zn, Pb, Cd, and Cu were due to anthropogenic activities.     

Distribution and accumulation of heavy metals in the sediments of Akkaya Dam,Nigde, Turkey

Twenty-one surface sediment samples were collected from Akkaya Dam. Heavy metal concentrations (Mo, Cu, Pb, Zn, Ni, Co, Mn, Fe, Cr, As, V and Cd), grain size, organic carbon and carbonate contents were studied in order to assess the extent of environmental pollution and to discuss the origin of these contaminants in sediments of dam. The sediments in the study area are mostly very fine sands. However, mud was observed in the northeast of the dam. Sediment pollution assessment was carried out using enrichment factor. The calculation of enrichment factors showed that Mo is depleted by 1.0 whereas Cu, Pb, Zn, Ni, Co, Mn, As, V, Cr and Cd are enriched by 3, 5.4, 7, 2.7, 2.2, 3.4, 42.3, 2.1, 1.8 and 7.2, respectively. Relatively high concentrations heavy metals occurred in north (textile industry area) and east (Karasu River) due to enrichment controlled by anthropogenic wastes. The results of correlation analysis show low–medium positive and negative correlations among metals, grain size, carbonate contents and organic carbon and indicate that heavy metals in sediments of the Akkaya Dam have different anthropogenic sources.     

An assessment of metal contamination risk in sediments of Hara Biosphere Reserve,southern Iran with a focus on application of pollution indicators

The aim of this study was to assess the pollution status of metals in sediments of Hara Biosphere Reserve using pollution indicators. For this purpose, sediment samples from nine locations were collected and characterized for metal content (Pb, Cr, Zn, Cu, and Fe) using the total digestion technique. Comparison of metal concentrations with that of sediment quality guidelines (SQGs) demonstrated no association with negative biological effects for Cu and Zn, while the values of Pb and Cr mainly illustrated to have association with negative biological effects. The results of the geo-accumulation index (I _geo) indicated no contamination for Cr, Cu, Zn, and Fe, while the values of Pb demonstrated to have moderate contamination based on I _geo values. The analysis of the enrichment factor (EF) showed no enrichment for Cu and Zn and minor enrichment for Pb and Cr. Similar results were also found for quantification of contamination (QoC) analysis, where the values of Cu and Zn demonstrated to have a geogenic source of contamination, while the values of Pb and Cr mainly illustrated to have an anthropogenic source of contamination. According to EF and QoC calculations, the values of Cu and Zn were derived mainly from natural processes and exposure of material from the earth’s crust, while the values for Pb and Cr were enriched by anthropogenic activities. The results of the contamination factor (C _f ⁱ ) demonstrated low contamination levels for Fe, Cr, Zn, and Cu and moderate contamination levels for Pb. The pollution load index (PLI), showing the overall contamination of metals, demonstrated moderate pollution status in the study area.     

Heavy metal enrichment in surface sediments from the SW Gulf of Mexico

The south west coastal zone in the Gulf of Mexico is an area with great industrial and agricultural development, which experiences intensive prospecting and extraction of hydrocarbons. After running through industrial, agricultural, and urban areas, waters from both the Jamapa River and La Antigua River arrive here. The rivers’ discharge areas of influence were estimated considering the textural and chemical composition of the supplied sediments. The main factors that determine sediment distribution were mineralogy, heavy minerals, carbonates, and anthropic contributions. The presence of metals in excess was evaluated using various pollution indicators, such as the enrichment factor, contamination factor, modified contamination factor, and geo-accumulation indexes. Data from different used contamination indexes show metal enrichments in As, Cu, Zn, Co, Cr, and V in La Antigua; As, Cu, and Cr in Jamapa; and As, Zn, and Pb in the Continental slope area. The adverse effects of metals on aquatic organisms were assessed using sediment quality guidelines that show Ni, As, Cu, and Cr may produce adverse effects on coastal areas. There was no evidence of contamination associated to the oil industry.     

Evaluation of metal contamination in sediments from north of Morocco: geochemical and statistical approaches

Concentrations of Fe, Mn, Cr, Cu, Ni, Pb, Zn, Cd and Hg were evaluated in surface sediments of two rivers from north of Morocco, known as Souani and Mghogha rivers. Significantly higher concentrations in mg kg^???1 dry weight (dw) of Mn (747.6 vs. 392.9), Cr (86.4 vs. 56.3), Zn (299.5 vs. 138.5) were found in sediment samples from Mghogha when compared with Souani river. Average concentrations of Cd and Hg in several sediment samples from both rivers were above the effect range median that predicts toxic effects to aquatic organisms. The calculation of enrichment factors showed that Mn, Cr, Cu and Ni were depleted, whereas Pb and Hg were enriched. The results of geoaccumulation index revealed that sediments of both rivers were unpolluted with most of the metals and moderately contaminated with Fe and Hg. Some of elevated concentrations of Hg, principally in Mghogha River, were due to anthropogenic sources including the direct discharges of industrial zone.     

Metal Pollution Assessment of Sediment and Water in the River Hindon, India

The metal pollution in water and sediment of the River Hindon in western Uttar Pradesh (India) was assessed for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The metal concentrations in water showed wide temporal variation compared with bed sediment because of variability in water discharge and variations in suspended solid loadings. Metal concentrations in bed sediments provided a better evaluation of the degree and the extent of contamination in the aquatic environment, Santagarh and Atali being the most polluted sites of the river. The ratio of heavy metals to conservative elements (Fe, Al, etc.) may reveal the geochemical imbalances due to the elevated metal concentrations normally attributed to anthropogenic sources. Metal/Al ratios for the bed sediments of the river Hindon were used to determine the relative mobility and general trend of relative mobility occurred Fe > Mn > Zn > Cr > Ni > Pb > Cu > Cd.     

Application of geoaccumulation index and enrichment factor for assessing metal contamination in the sediments of Kafrain Dam, Jordan

An investigation is reported of the degree of metal pollution in the sediments of Kafrain Dam and the origin of these metals. Fourteen sampling sites located at Kafrain Dam were chosen for collecting the surface, cutbank, and dam bank sediment samples. The sediment samples have been subjected to a total digestion technique and analyzed by atomic absorption spectrometer for metals including Pb, Zn, Cd, Ni, Co, Cr, Cu, Mn, and Fe. XRD analyses indicate that the sediments of Kafrain Dam are mainly composed of calcite, dolomite, quartz, orthoclase, microcline, kaolinite, and illite reflecting the geology of the study area. The enrichment factor (EF) and geoaccumulation index (I _geo) have been calculated and the relative contamination levels assessed in the study area. The calculations of I _geo are found to be more reliable than of those of EF. The enrichment of metals in the study area has been observed to be relatively high. I _geo results reveal that the study area is not contaminated with respect to Ni, Co, Cr, Cu, and Mn; moderately to strongly contaminated with Pb; and strongly to extremely contaminated with Cd and Zn. The high contents of Pb, Cd, and Zn in the study area result from anthropogenic activities in the catchment area of the dam site. These sources mainly include the agricultural activities, sewage discharging from various sources within the study area (effluent of wastewater treatment plants, treated and untreated wastewaters, and irrigation return water), and the several industries located in the area. Degrees of correlations among the various metals in the study area are suggested by the results and the intermetallic relationship.     

Identifying the origin of atmospheric inputs of trace elements in the Prades Mountains (Catalonia) with bryophytes, lichens, and soil monitoring

The biomonitors Hypnum cupressiforme and Xanthoria parietina were used to assess the deposition of trace elements and their possible origin in the Prades Mountains, a protected Mediterranean forest area of NE Spain with several pollution sources nearby. Al, As, Cd, Co, Cu, Cr, Ni, Pb, Sb, Ti, V, and Zn were determined in 16 locations within this protected area. Soil trace element concentrations were also ascertained to calculate enrichment factors (EF) and use them to distinguish airborne from soilborne trace element inputs. In addition, lichen richness was measured to further assess atmospheric pollution. EF demonstrated to be useful not only for the moss but also for the lichen. Cd, Cr, Cu, Ni, and Zn presented values higher than three in both biomonitors. These trace elements were also the main ones emitted by the potential sources of pollutants. The distance between sampling locations and potential pollution sources was correlated with the concentrations of Cu, Sb, and Zn in the moss and with Cr, Ni, and Sb in the lichen. Lichen richness was negatively correlated with lichen Cu, Pb, and V concentrations on dry weight basis. The study reflected the remarkable influence that the pollution sources have on the presence of trace elements and on lichen species community composition in this natural area. The study highlights the value of combining the use of biomonitors, enrichment factors, and lichen diversity for pollution assessment to reach a better overview of both trace elements’ impact and the localization of their sources.     

Spatial distribution and metal contamination in the coastal sediments of Al-Khafji area,Arabian Gulf,Saudi Arabia

To document the spatial distribution and metal contamination in the coastal sediments of the Al-Khafji area in the northern part of the Saudi Arabian Gulf, 27 samples were collected for Al, V, Cr, Mn, Cu, Zn, Cd, Pb, Hg, Sr, As, Fe, Co, and Ni analysis using inductively coupled plasma-mass spectrometer (ICP-MS). The results revealed the following descending order of the metal concentrations: Sr > Fe > Al > As > Mn > Ni > V > Zn > Cr > Cu > Pb > Co > Hg > Cd. Average levels of enrichment factor of Sr, As, Hg, Cd, Ni, V, Cu, Co, and Pb were higher than 2 (218.10, 128.50, 80.94, 41.50, 12.31, 5.66, 2.95, 2.90, and 2.85, respectively) and that means the anthropogenic sources of these metals, while Al, Zn, Cr and Mn have enrichment factor less than 2, which implies natural sources. Average values of Sr, Hg, Cd, Cr, Ni, and As in the coastal sediments of Al-Khafji area were mostly higher than the values recorded from the background shale and earth crust and from those results along coasts of the Caspian Sea and the Mediterranean Sea. The highest levels of Cu in the northern part of the studied coastline might be due to Al-Khafji desalination plant, while levels of Al, Ni, Cr, Fe, Mn, Pb, and Zn in the central part may be a result of landfilling and industrial sewage. The highest levels of As, Cd, Co, Cu, Hg, and V in the southern part seem to be due to oil pollutants from Khafji Joint Operations (KJO). The higher values of Sr in the studied sediments in general and particularly in locality 7 could relate to the hypersalinity and aragonitic composition of the scleractinian corals abundant in that area.     

Chemometric study on the trace metal accumulation in the sediments of the Cochin Estuary―Southwest coast of India

The distribution and accumulation of trace metals in the sediments of the Cochin estuary during the pre-monsoon, monsoon and post-monsoon periods were investigated. Sediment samples from 14 locations were collected and analysed for the metal contents (Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb), organic carbon, total nitrogen, total sulphur and grain size. The data were processed using statistical tools like correlation, factor and cluster analysis. The study revealed an enrichment of Cd and Zn in the study area particularly at station 2, which is confirmed by enrichment factor, contamination factor and geoaccumulation index. The factor analysis revealed that the source of Cd and Zn may be same. The study indicated that the spatial variation for the metals like Mg, Cr, Fe, Co, Ni, Cu, Zn, Cd and Pb were predominant unlike Mn which shows a temporal variation. The strong association of trace metals with Fe and Mn hydroxides and oxides are prominent along the Cochin estuary. The anthropogenic inputs of industrial effluents mainly control the trace metals enrichment in the Cochin estuary.