Startseite Evaluation of temporary seasonal variation of heavy metals and their potential ecological risk in Nzhelele River, South Africa
Artikel Open Access

Evaluation of temporary seasonal variation of heavy metals and their potential ecological risk in Nzhelele River, South Africa

  • Joshua N. Edokpayi EMAIL logo , John O. Odiyo , Elizabeth O. Popoola und Titus A.M. Msagati
Veröffentlicht/Copyright: 9. Dezember 2017
Artikel downloaden (PDF)
Open Chemistry
Aus der Zeitschrift Open Chemistry Band 15 Heft 1

Abstract

Surface water is often used as alternative source of drinking water in many regions of the world where the potable water supply is erratic or not present. The concentration of heavy metals was assessed using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The impact of temporary seasonal variation on the contamination level was also assessed. Contamination factor (CF) and Hakanson’s potential ecological risk (Er and RI) indices were used to evaluate the toxicity levels of the metals in the sediments of the river. Higher concentrations of Fe, Mn, Pb, Cu and Zn were determined in the dry season in the river water whereas in the sediments higher levels were recorded for Al, Fe, Cd, Cr, Cu and Zn in the wet season. The average CF values for all the metals showed a low contamination level in the sediment, except for Cu and Cd which had moderate and considerable contamination levels, respectively. Similarly, Cu showed a moderate ecological risk level (Er = 62.90) only in March 2014, for other months Cu and the other metals investigated had Er values < 40 which implies low ecological risk. The mean relative abundance of heavy metals in the sediments follows the trend Al>Fe>Mn>u>Zn>Cr>Pb>Cd.

Keywords: Contamination factor; risk analysis; sediment contamination; seasonal variation; trace metals; human health; water quality

1 Introduction

Contamination of freshwater courses and their sediments by heavy metals is a global problem which has attracted policy makers and researchers because of the toxicity associated with them as well as their bioaccumulation potential [1]. This has led to the formulation of several sediment quality guidelines (SQGs) which have been useful in identifying pollutants of concern [1,2]. Based on information gathered from the SQGs, adequate monitoring frameworks have been designed. Cevik et al. [3] reported that SQGs are useful for the assessment of the health of sediment ecosystems as well as the protection of benthic organisms in freshwater ecosystems. Apart from various SQGs, some other indices have been formulated to test the contamination level and ecological risk of single and total heavy metals in sediments for example the geoaccumulation index (Igeo), enrichment factor (EF), Newrow integrated pollution index (Pn), contamination factor (CF) and ecological risk index (RI) [4,5,6,7,8,9]. Background levels of heavy metals in sediments of various countries are often required to calculate the relative toxicity of heavy metals in sediments but due to lack of such data in some countries, average heavy metals levels in sedimentary rock, continental crust, world shale, among others are often employed [1,6,10]. In this study, we used the contamination factor and ecological risk index developed by Hakanson which is based on the assumption that the sensitivity of the aquatic system depends on its productivity [1,5]. He used a toxic-response factor for a given heavy metal [1].

The concentration of heavy metals, exposure route, duration of exposure, age, genetic, chemical species as well as the nutritional status of the exposed individuals are part of various factors that influence the potential toxicity of heavy metals to humans [11]. Heavy metals are known to be toxic, persistent and have bio-accumulation tendencies in environmental media [12,13,14]. Once released, they can stay for exceptionally long period of time, resisting degradation and undergoing various chemical processes in water. They are easily converted into more toxic forms by microorganisms and converted into organic forms, some of which can be harmful to humans and aquatic ecosystems [12,15,16,17]. Monitoring of sediments is important because they serve as both carriers and sinks for pollutants, and reflect the history and anthropogenic inputs of the pollutants into the aquatic ecosystem [1,3,18]. Metals adsorbed onto sediments can easily be released under suitable conditions (such as change in temperature, pH, dissolved oxygen as well as the solubility of the chemical species) into the water column therefore acting as a source of secondary pollution [19,20]. The National Research Council of America [21] and Knox et al. [22] reported that trace metal contaminated sediments can cause direct and indirect risks as these metals are easily absorbed and become bio-accumulated in sea foods which may lead to possible human exposure.

Heavy metal contamination of rivers and sediments have been linked to several human activities that occur both far and close to the natural resource such as settlements, farms, game reserves, car wash, mining industries, storm water runoff, and wastewater treatment facilities [23]. de Melo Gurgel et al. [24] and Chaves et al. [23] reported that anthropogenic activities performed very close to rivers poses threat to the aquatic ecosystems and humans as contaminated water becomes a channel through which several diseases are spread to people living around the water resource. High levels of heavy metals have been reported in different species of aquatic organisms such as macrophytes, phytoplanktons, zooplanktons, prawns and fish in concentration beyond the permissible limits and this serves as a pathway to humans [25,26]. Other studies have implicated high concentration of heavy metals in the aquatic ecosystems to have adverse effects on benthic organisms, which include retarded growth, change in reproduction cycles and death in some species of fish [1,27,28,29]. High heavy metal levels in freshwater makes them unsuitable for human consumption, livestock watering and irrigation. Studies on the evaluation of the potential risk of heavy metals in South African river systems is limited and this study is the first to evaluate the potential ecological risk associated with heavy metals in Nzhelele River sediments. The objective of this study is to (i) assess heavy metals contamination of Nzhelele River which is often used by people for various purposes, (ii) investigate the effects of seasonal variations on the level of metals determined and (iii) to evaluate the possible ecological risk of the metals levels found.

1.1 Study area

Nzhelele River is located between latitudes 22°53’15.8” S and 22°54’5” S and longitudes 30°11’10.2” E and 30°11’23.5” E in the Limpopo Province of South Africa (Figure 1) [30]. Major land uses include formal and informal settlements, subsistence agriculture and the Siloam waste stabilization ponds (WSPs) which release effluents into the river. The study area is semi-arid with a shortage of potable water supplies. Residents depend largely on the abstraction of water from the Nzhelele River to meet their water needs without any form of treatment. Nzhelele River’s catchment area is 2, 436 square kilometers and it is a major water watercourse in the Limpopo Province of South Africa [31]. Rainfall is highly seasonal with 95% occurring between October and April [30]. The region is characterized by a warm wet season which is associated with high temperatures up to 40°C usually between October and March (with peak precipitation in January and February) and cold dry season (April-September) [32].

Figure 1 Map of the study area [30].
Figure 1

Map of the study area [30].

2 Materials and Methods

2.1 Sampling

Thirty-six water and thirty-three sediment samples were collected randomly from different sampling sites along Nzhelele River from January to June 2014. The sampling bottles (polyethylene) were washed using anionic detergents and then rinsed with tap water followed by distilled water. Concentrated nitric acid (5%) was added to samples collected for total metal determination. Physicochemical parameters like pH and electrical conductivity (EC) were measured insitu using 340i pH and EC multimeter (WTW, Weilheim, Germany) [33]. Turbidity of the river water was also measured using TB 200 turbidimeter (Orbeco Hellige, Sarasota, FL, USA) [33]. The samples and control were transported, preserved, digested and analyzed bearing in mind issues of quality control and assurance as recorded in Edokpayi et al. [34].

2.2 Analysis of Heavy Metals

The analysis of the digested samples was performed with an inductively coupled plasma optical emission spectrometer (ICP-OES) ICAP 6500, Thermo Scientific, Johannesburg, South Africa. The condition setting for the ICP-OES is presented in supplementary data 1. Calibration standards were prepared from a multi-element stock solution of 100 mg/L. The detection of the method limit was determined for each element by adhering to the procedures of the United States Environmental Protection Agency (US EPA) [35] method 200.7. Spike recovery method was used to validate the analytical method and instrument used for the analysis [34]. Statistical analysis was performed using the IBM SPSS statistics package 20.

Ethical approval

The conducted research is not related to either human or animals use.

3 Results and Discussion

Acceptable recoveries in the range of 90-110% and 85-120% for water and sediment samples, respectively were obtained from the spike recovery test. The method detection limit for metals in the water and sediment samples varied between 1 µg/L for pb to 25 µg/L for Al [32].

3.1 Physico-chemical parameters

The average pH values of Nzhelele River over the study period were found to be in the range of 7.21-7.76 (Supplementary data 2), which complied with the Department of Water Affairs and Forestry (DWAF) and that of the World Health Organization (WHO) guideline value of 6-9 for domestic water use [28,36]. An average pH value of 7.62 was obtained in the wet season which was slightly higher than 7.47 in the dry season. This level did not differ significantly (p>0.05) for both the wet and the dry season. This implies that seasonal variations do not lead to considerable changes in pH. Weak and non-significant correlations were computed for pH values in the wet and the dry seasons. Turbidity is usually associated with reduced penetration of light rays into the river which can adversely affect benthic organisms [19]. The average turbidity values obtained decreased consistently from 678 NTU (January) to 1.4 NTU (June 2014) (Supplementary data 2). The higher values obtained in the wet season (January-March) is due to higher rainfall than in the dry season (April-June). The mean values obtained during the sampling period for both seasons were higher than the DWAF and WHO standards of ≤1 NTU for domestic water. A positive and significant correlation was computed for turbidity levels for both seasons (r = 0.723, p<0.01). Seasonal variations in turbidity levels in various rivers in South Africa have been reported in the literature [37,38].

The average EC values were in the range of 8-14 mS/m (Supplementary data 2), with the values for the wet and dry seasons differing significantly (p<0.05), indicating that seasonal variations have the potential to cause change in the conductivity. EC values in both seasons showed a weak correlation with each other which was not significant (r = 0.210, p>0.05). The lower values of EC observed in the wet season could be dilution of dissolved salts due to rainfall [39]. As rainfall decreases, the level of EC increases due to the concentration of the ions due to evaporation in the river. Similar findings were reported in the literature [40,41]. However, Anhwange et al. [42] and Shabalala et al. [43] recorded higher values of EC in the wet season which was attributed to runoff of ionic materials from soils into the rivers during rainfall. The values obtained in this study for both seasons were within the recommended guidelines of DWAF (70 mS/m) [28] and WHO (600 mS/m) [36] for domestic water use.

3.2 Trace metals concentrations

The monthly average concentrations of Al ranged from 1.172-29.094 mg/L (Table 1) in the water samples and 2331-4707 mg/kg in the sediments of Nzhelele River (Figure 2). The levels obtained in the water samples exceeded the DWAF threshold value (0.15 mg/L) for domestic water use. Highest Al concentration was obtained in January (29.094 mg/L) in which rainfall was at its peak. The reason for this could be attributed to high surface runoffs from agricultural land and soil rich in Al during incidences of rainfall [34]. The concentration of Al in the aqueous environment is pH dependent. Al is usually soluble and toxic to aquatic species at acidic pH. It is also soluble at alkaline pH but non-toxic [44]. The World Health Organization (WHO) do not have a guideline value for Al as it is considered to be of no risk to humans at low concentrations but a health based value of 0.9 mg/L was adopted by WHO [36]. High Al concentration in domestic water have been correlated to Alzheimer’s disease and renal failure [44]. The average levels of Al obtained in this study exceeded this guideline value which implies that the consumption of this Al rich water could have adverse effects on human health.

Figure 2 Heavy metal concentration (mg/kg) in Nzhelele sediments from january-june 2014, S1-S6 represent various sampling sites.
Figure 2

Heavy metal concentration (mg/kg) in Nzhelele sediments from january-june 2014, S1-S6 represent various sampling sites.

Table 1

Average level of trace metal in Nzhelele River water.

Trace metal concentration (mg/L)Sampling Months
JanuaryFebruaryMarchAprilMayJune
Al29.094±9.263.089±1.121.172±0.413.550±1.123.704±2.421.834±1.06
Cd0.001±0.0010.001±0.0020.002±0.0010.0004±0.010.001±0.0020.001±0.001
Cr0.396±0.080.363±0.050.285±0.820.045±0.010.386±0.050.082±0.16
Cu0.066±0.010.027±0.010.028±0.010.025±0.010.048±0.030.043±0.03
Fe4.991±2.471.180±0.181.028±0.241.777±0.443.001±1.121.172±0.84
Mn0.145±0.080.052±0.010.214±0.050.545±0.230.516±0.090.281±0.17
Pb0.010±0.0010.001±0.0010.002±0.000.011±0.010.013±0.010.010±0.001
Zn0.115±0.020.042±0.010.046±0.010.065±0.020.131±0.070.057±0.02

Currently, there is no sediment quality guidelines (SQGs) in South Africa for metal concentration in freshwater sediments [45] and therefore the SQGs of the Canadian Council of Ministers of the Environment (CCME) for sediments in freshwater was employed in this study [2]. Currently no guideline value has been assigned to Al. The Al concentrations in the river waters differed significantly to their levels in the sediments (p<0.01) (Supplementary data 3), indicating that Al concentrations in the sediments is different from their levels in the water of Nzhelele River as expected. The levels of Al determined can be linked to its relative abundance in earth and high levels of Al have been previously recorded in South Africa river systems [12,15,20]. Also, the use of Al-containing materials within the river catchment area could also be responsible for the high levels as there is no effective solid waste collection and disposal system in the villages surrounding the river. Therefore, during rainfall the storm water generated can easily carry Al-containing materials to the river and this possibly explains its higher concentration determined in the wet season.

The average concentration of Fe was in the range of 1.028-4.991 mg/L (Table 1), which exceeded the DWAF threshold value of 0.1 mg/L for all the sampling period. In the sediments, the mean Fe concentration varied between 1175-5252 mg/kg (Figure 2). There is no CCME SQG value for Fe but the levels determined were high. Mn is often considered as one of the least toxic metals and its level fluctuated between 0.052-0.545 mg/L during the period of sampling, which exceeded the DWAF [28] threshold limits for domestic (0.05 mg/L) and irrigation (0.02 mg/L) water uses. The mean lowest and highest concentrations of Mn in the sediments of Nzhelele were 120 mg/kg (June) and 516 mg/kg (April) respectively. There is no CCME guideline for Mn in freshwater sediment. The concentrations of Mn in the water of Nzhelele River varied significantly (p<0.05) with their concentrations in the sediments (Supplementary data 4).

The average concentrations of Cd ranged between 4.0 x 10-4 and 2 x 10-3 mg/L and complied with the 0.003 mg/L guideline of WHO [36] and the DWAF [28] threshold value of (0.005 mg/L) and therefore the levels of Cd determined in this study would not constitute a human health concern. In the sediments, the average concentrations of Cd varied from 0.006 - 4.056 mg/kg (Figure 2). CCME [2] guideline value for Cd in sediment is 0.6 mg/kg and was exceeded in Nzhelele Rivers from January-March. The other sampling months had values below 0.6 mg/kg (Figure 2). Wastewater effluents and run-offs from agricultural lands and landfills are the major anthropogenic sources of Cd in aquatic ecosystem [46]. Cd in the river water did not vary significantly (p > 0.05) with their levels in the sediments. The mean Pb concentrations in the river waters were in the range 0.001-0.013 mg/L (Table 1). The concentration of Pb determined did not comply with DWAF [28] set value of 2 x10-4 mg/L for the protection of aquatic ecosystems. However, the concentrations of Pb in the river water exceeded the benchmark value of 0.01 mg/L in April (0.019 mg/L) and May (0.013 mg/L) but complied for the rest of the months. In the sediments, Pb average concentrations varied between 0.248 mg/kg and 2.71 mg/kg (Figure 2) and was below the CCME [2] tolerable limit of 32.2 mg/kg for Pb in freshwater sediments. There was, however, a significant difference (p< 0.01) in the concentration of Pb in the river waters and sediments (Supplementary data 3).

The average Cr concentrations in the river water ranged from 0.045-0.396 mg/L (Table 1) and exceeded the DWAF and WHO guideline value of 0.05 mg/L for domestic water use except for the month of April (0.045 mg/L) [28,36]. The average concentrations of Cr in the sediments ranged between 7.804 mg/kg and 51.288 mg/kg (Figure 8). The CCME [2] guideline value for Cr in freshwater sediments (37.3 mg/kg) was exceeded in January and April although the values found in February (32.193 mg/kg) and March (31.061 mg/kg) were also close to the threshold value. However, the difference in the means of Cr determined in the water and sediments sample was statistically significant (p<0.05) (Supplementary data 4).

Average Cu concentrations in the water samples varied between 0.0257 mg/L and 0.066 mg/L and did not exceed the benchmark values of 2 mg/L [36] and 1 mg/L [28] for domestic water use. In the sediments, the levels of Cu ranged between 2.182-566 mg/kg (Figure 2). The mean concentration of Cu in the sediments of the river complied with the guideline value of 37.5 mg/kg assigned by CCME [2] for Cu in freshwater sediments in all the sampling months except in March (566 mg/kg). Similarly, significant differences exist in the mean of Cu concentration in water and sediments (p<0.05).

Zn average concentration in the river water ranged from 0.042-0.131 mg/L (Table 1), below the 3 mg/L assigned by DWAF [28] for domestic water use. The mean concentration of Zn in the sediments ranged between 2.605 and 202 mg/kg (Figure 2), which complied with the CCME [2] threshold value of 123 mg/kg for the protection of aquatic ecosystems except for March (202 mg/kg). The concentrations of Zn in the water and sediments varied significantly (p<0.05).

3.3 Influence of temporary seasonal variation of heavy metals in Nzhelele River

Higher concentrations of Al in the water of the river were found in the wet season (10.565 mg/L) compared to the dry season (2.963 mg/L) (Table 2a). The mean difference of Al in the water varied significantly (p<0.05) for both seasons. Similarly, the mean concentration of Al in the sediments was higher in the wet season (4312 mg/kg) compared to the dry season (3147 mg/kg) but the mean difference did not vary significantly (p>0.05) (Table 2b). Higher concentrations of Fe were determined in the river water in the dry season (5.804 mg/L) than in the wet season (2.304 mg/L), this difference was statistically significant (p>0.05). In the sediment, the average levels of Fe in the wet (3206 mg/kg) and in the dry (2862 mg/kg) season did not vary significantly (p>0.05). In the river water, a higher concentration of Mn was determined in the dry season (0.755 mg/L) than in the wet season (0.129 mg/L) but this level in both seasons did not vary significantly (p>0.05). Similarly, in the sediment Mn recorded a higher concentration during the dry season (306 mg/kg) than in the wet season (199 mg/kg) but this difference was not statistically significant (p>0.05). High concentration of Cd in sediment was only observed during the wet season (2.52 mg/kg) and could be attributed to high precipitation which subsequently led to higher run-off of Cd containing materials from agricultural and semi industrial lands in to the rivers [21].

Table 2a

Mean concentrations of trace metal levels (mg/L) in the wet and the dry season of the water of Nzhelele River and the difference in their means at p = 0.05.

MetalsWetDryp-value
Al10.572.960.03
Cd0.0010.0010.078
Cr0.3440.1870.008
Cu0.3850.4030.789
Fe2.3045.8040.382
Mn0.1290.7550.063
Pb0.0530.1650.016
Zn0.0650.0860.223

Table 2b

Mean concentrations of trace metal levels (mg/kg) in the wet and the dry season of Nzhelele River sediments and the difference in their means at p = 0.05.

MetalsWetDryp-value
Al431231470.064
Cd4.160.0820.00
Cr38.1826.220.169
Cu20.357.2860.025
Fe320628620.771
Mn1993060.324
Pb1.8471.1220.470
Zn31.819.4110.103

The levels of Cd in the river sediments for the wet and the dry seasons varied significantly (p<0.01). In the river water, the same concentration of Cd (0.001 mg/L) was determined in both seasons. Average Pb concentration in the river water was higher in the dry season (0.165 mg/L) than in the wet season (0.053 mg/L) and their mean difference varied significantly (p<0.05).No significant variation was calculated for the average levels of Pb in the river sediments between the wet (1.847 mg/kg) and dry seasons (1.122 mg/kg) (p>0.05). Higher levels of Cr were determined in the wet season (0.344 mg/L) than in the dry season (0.187 mg/L) and this difference in means was statistically significant (p<0.01). The concentration of Cr in the sediments was higher in the wet season (38.18mg/kg) than the dry season (26.22 mg/kg) but this mean difference was statistically insignificant (p>0.05). Seasonal variation determined in the levels of Cu in the water for both the wet (0.385 mg/L) and the dry (0.403 mg/L) seasons was not significantly different (p>0.05). Higher levels of Cu in the sediments was recorded in the wet season (20.35 mg /kg). Seasonal variation in Cu levels of the sediments was significant (p<0.05) for the wet and the dry seasons. In the wet season, Zn concentration was lower (0.062 mg/L) than that of the dry season (0.086 mg/L), this could be due to dilution effects in the wet season and evaporation effects in the dry season. The difference in the means for both seasons in the river water did not vary significantly (p>0.05). Higher levels of Zn were recorded in the sediments during the wet season (31.81 mg/kg) than in the dry season (7.285 mg/kg) but the mean difference was not significant (p>0.05).

Metal levels in rivers are largely influenced in the wet season by storm water run-off from the surroundings on the river catchment and this usually leads to an increase in heavy metal concentration. High dilution of heavy metals due to increased water volume and flow is another factor that can influence the concentration of metals in a river during the wet season. In the dry season, there is a concentration of heavy metals due to reduced water volume and flow and increased evaporation from water bodies [34]. This can consequently lead to increased levels of heavy metals in the river. In this study, higher levels of heavy metals were determined in the Nzhelele River in the dry season (Cu, Fe, Mn, Pb and Zn) than in the wet season (Al, and Cr). Similar concentrations of 0.001 mg/L were determined for Cd. Islam et al. [47] reported that metal concentration is expected to be low during the wet season due to the dilution effect on heavy metals but some site-specific activities and source of metal contamination could lead to an exception to this general trend. Different trends of seasonal effects on heavy metal levels in water end sediments have been reported [47,48,49,50].

3.4 Pontential ecological risk of trace metals in Nzhelele River sediments

The risk associated with the levels of trace metals determined in the sediments was computed using the pontential ecological index (RI) reported by Hakanson [5] which defined RI as

RI=∑i=1nEri(1)

Where Eri refers to the potential ecological risk coefficient of a single element and it is defined as

Eri=Tri×Cfi(2)

Where Tri is the toxic response factor for a given trace metal. The Tri values have been assigned for Cd, Pb, Cr, Cu, Mn and Zn as 30, 5, 2, 5,1 and 1 respectively [5, 10, 58]. Cfi represents the contamination factor which is used to measure the level of contamination of sediments by trace metals. Cfi is defined as

Cfi=CiCo(3)

ci refers to each metal concentration in the sediments; and co is the background value of trace metals in sediments. There are no background values for trace metals in sediments in South Africa [43] and therefore the shale average concentrations of trace metals in global sediments reported by Turekian and Wedepohl [10] were used. Cf < 1 infers a low contamination of metals in the sediments, 1 ≤ Cf ≤ 3 infers a moderate contamination of sediments and 3 ≤ Cf≤ 6 represents considerable trace metal contamination of sediments and Cf> 6 represent very high contamination of sediments [1,5,51]. From the results presented in Table 3, CF values for all the elements in each of the sampling months were less than 1, except for Cu and Zn in March and Cd in January-March. The average CF values for all the metals showed a low contamination level in the sediment, except for Cu and Cd which had a moderate and considerable contamination level, respectively. Most of the metals (Al, Cd, Cr, Cu, Pb and Zn) showed a higher contamination level in the wet season. The CF values for Mn were higher in the dry season while Fe had the same CF value for both seasons.

Table 3

Monthly average contamination factor (CF) of trace metals in Nzhelele River sediments.

AlFeCrCuMnZnPbCd
JanuaryWet0.060.090.570.600.330.530.0813.5
FebruaryWet0.060.060.360.490.180.370.074.33
MarchWet0.050.050.3412.580.202.130.147.33
AprilDry0.050.110.500.330.610.190.110.27
MayDry0.040.070.310.130.330.090.050.03
JuneDry0.030.020.090.050.140.030.010.03
Mean0.050.070.392.360.300.560.084.25
Shale Average [10]8000047200904585095200.3

The Er and RI values are associated with a scale of pollution levels of sediments; Er < 40 has low ecological risk; 40 < Er ≤ 80, moderate ecological risk; 80 < Er r ≤ 160, appreciable ecological risk; 160 < Er ≤ 320, high ecological risk; and >320, serious ecological risk [1,5,51,52]. The values of Er for all the metals were < 40 implying low ecological risk except for Cu in March and Cd between January-March (Table 4). There was an appreciable risk for Cd in February, high ecological risk in March and a seriously ecological risk in January. Copper had a moderate ecological risk in March. The mean values of Er calculated for each of the metals throughout the sampling period showed low ecological risk for all the metals except for Cd which showed an appreciable ecological risk. For most of the metals, higher values of Er were computed during the wet season than in the dry season.

Table 4

Monthly average Eir and RI of trace metals in Nzhelele River sediments.

CrCuMnZnPbCdRIRisk grade
JanuaryWet1.143.000.330.530.40405.00410.40considerable
FebruaryWet0.722.450.180.370.35129.90133.97low
MarchWet0.6862.900.202.130.70219.90286.51moderate
AprilDry1.001.650.610.190.558.1012.10low
MayDry0.620.650.330.090.250.902.84low
JuneDry0.180.250.140.030.050.900.74low
Mean0.7211.820.300.562.30127.45141.10low

The RI method covers a variety of domains (biological toxicology, environmental chemistry as well as ecology) for the comprehensive evaluation of potential ecological risk caused by trace metals in sediments [5,51]. RI values for water bodies are classified as: RI < 150—low ecological risk; 150 < RI < 300—moderate ecological risk; 300 < RI < 600—considerable ecological risk and RI > 600—very high ecological risk [1,5,10,51]. Sediment pollution was low except for the months of January and March which coincide with the highest rainfall recorded in the study area in 2014. Cd played a major role in the high levels of RI computed for the months of January-March. The overall ecological risk for all the metals evaluated was low. The major contributing factor to these high levels could be due to run-off from agricultural land, discharge of raw and partially treated water from the WSPs within the river catchment into the river.

4 Conclusion

Al and Fe were found in higher concentrations in the river water and sediments compared to the other metals investigated. In the water samples higher levels of metals were determined in the dry season except for Al, Cd and Cr. Conversely, higher levels were determined in the sediment samples of the river during the wet season than the dry season except for Mn and Pb. Possible sources of pollution include: run-off from settlements, agricultural soils, discharge of partially treated wastewater, poor solid waste management systems and several non-point sources. The Nzhelele River is not suitable for domestic purposes as most metals exceeded the benchmark compliance values. Apart from Cd, all metals investigated in the river water differed significantly with their levels in the sediments. Significant seasonal variations in the levels of the metals in the river water were only computed for Al, Pb and Cr while in the sediments only Cu and Cd varied significantly. It is believed that the levels of metals computed for Nzhelele River are influenced greatly by dilution and evaporation processes. Higher contamination levels and potential ecological risk were calculated for most of the metals in the wet season than in the dry season, however, the mean ecological risk for all the metals evaluated in the sampling period was low.

Acknowledgments

The authors express their profound gratitude to the Research and Publication Committee of the University of Venda for funding this research (Grant no: S357).

  1. Conflict of interest: Authors state no conflict of interest.

References

[1] Li J., Risk Assessment of Heavy Metals in Surface Sediments from the Yanghe River, China. Int. J. Environ. Res. Public Health., 2014,11, 12441–12453. 10.3390/ijerph111212441Suche in Google Scholar

[2] Canadian Council of Ministers of the Environment. Canadian sediment quality guidelines for the protection of aquatic life [Internet]. Manitoba: Canadian Environmental Quality Guidelines, 1999, Available: http://st-ts.ccme.ca/en/index.htmlSuche in Google Scholar

[3] Çevik F., Göksu M.Z.L., Derici O.B., Findik Ö., An assessment of metal pollution in surface sediments of Seyhan dam by using enrichment factor, geoaccumulation index and statistical analyses. Environ. Monit. Assess., 2009, 152, 309, 10.1007/s10661-008-0317-3Suche in Google Scholar

[4] Tzoraki O., Karaouzas I., Patrolecco L., Skoulikidis N., Nikolaidis N.P., Polycyclic Aromatic Hydrocarbons (PAHs) and Heavy Metal Occurrence in Bed Sediments of a Temporary River. Water Air Soil Pollut., 2015, 226, 421, 10.1007/s11270-015-2671-4Suche in Google Scholar

[5] Hakanson L., An ecological risk index for aquatic pollution control. A sedimentological approach. Water Res., 1980, 14, 975–1001, 10.1016/0043-1354(80)90143-8Suche in Google Scholar

[6] Mueller G., Schwermetalle in den Sedimenten des Rheins–Veraenderungen seit. Umschau, 1979, 79, 778–783.Suche in Google Scholar

[7] Qiang L., Yang W., Jingshuang L., Quanying W., Mingying Z., Grain-size distribution and heavy metal contamination of road dusts in urban parks and squares in Changchun, China. Environ. Geochem. Health, 2015, 37, 71–82, 10.1007/s10653-014-9631-6Suche in Google Scholar

[8] He D., Shi X., Wu D., Particle-size distribution characteristics and pollution of heavy metals in the surface sediments of Kuitun River in Xinjiang, China. Environ. Earth Sci., 2016, 75, 104, 10.1007/s12665-015-4882-9Suche in Google Scholar

[9] Wan L., Xu L., Fu Y., Contamination and Risk Assessment of Heavy Metals in Lake Bed Sediment of a Large Lake Scenic Area in China. Int. J. Environ. Res. Public Health., 2016, 13, 10.3390/ijerph13070741Suche in Google Scholar

[10] Turekian K.K., Wedepohl K.H., Distribution of the Elements in Some Major Units of the Earth’s Crust. Geol. Soc. Am. Bull., 1961, 72, 175–192, 10.1130/0016-7606(1961)72 [175: DOTEIS] 2.0.CO;2Suche in Google Scholar

[11] Tchounwou P.B., Yedjou C.G., Patlolla A.K., Sutton D.J., Heavy Metals Toxicity and the Environment. EXS, 2012, 101, 133–164, 10.1007/978-3-7643-8340-4_6Suche in Google Scholar PubMed PubMed Central

[12] Xu F., Tian X., Yin X., Yan H., Yin F., Liu Z., Trace metals in the surface sediments of the eastern continental shelf of Hainan Island: Sources and contamination. Mar. Pollut. Bull., 2015, 99, 276–283, 10.1016/j.marpolbul.2015.07.055Suche in Google Scholar PubMed

[13] Wang H., Wang J., Liu R., Yu W., Shen Z., Spatial variation, environmental risk and biological hazard assessment of heavy metals in surface sediments of the Yangtze River estuary. Mar. Pollut. Bull., 2015, 93, 250–258, 10.1016/j.marpolbul.2015.01.026Suche in Google Scholar PubMed

[14] Zhang L., Shi Z., Zhang J., Jiang Z., Wang F., Huang X., Spatial and seasonal characteristics of dissolved heavy metals in the east and west Guangdong coastal waters, South China. Mar. Pollut. Bull., 2015, 95, 419–426, 10.1016/j.marpolbul.2015.03.035Suche in Google Scholar PubMed

[15] Hu B., Cui R., Li J., Wei H., Zhao J., Bai F., et al., Occurrence and distribution of heavy metals in surface sediments of the Changhua River Estuary and adjacent shelf (Hainan Island). Mar. Pollut. Bull., 2013, 76, 400–405, 10.1016/j.marpolbul.2013.08.020Suche in Google Scholar PubMed

[16] Bastami K.D., Bagheri H., Kheirabadi V., Zaferani G.G., Teymori M.B., Hamzehpoor A., et al., Distribution and ecological risk assessment of heavy metals in surface sediments along southeast coast of the Caspian Sea. Mar. Pollut. Bull., 2014, 81, 262–267, 10.1016/j.marpolbul.2014.01.029Suche in Google Scholar PubMed

[17] Zhao G., Ye S., Yuan H., Ding X., Wang J., Distribution and contamination of heavy metals in surface sediments of the Daya Bay and adjacent shelf, China. Mar. Pollut. Bull., 2016, 112, 420–426, 10.1016/j.marpolbul.2016.07.043Suche in Google Scholar PubMed

[18] Devesa-Rey R., Díaz-Fierros F., Barral M.T., Trace metals in river bed sediments: An assessment of their partitioning and bioavailability by using multivariate exploratory analysis. J. Environ. Manage., 2010, 91, 2471–2477, 10.1016/j.jenvman.2010.06.024Suche in Google Scholar PubMed

[19] Roberts D.A., Causes and ecological effects of resuspended contaminated sediments (RCS) in marine environments. Environ. Int., 2012, 40, 230–243, 10.1016/j.envint.2011.11.013Suche in Google Scholar PubMed

[20] Hill N.A., Simpson S.L., Johnston E.L., Beyond the bed: effects of metal contamination on recruitment to bedded sediments and overlying substrata. Environ Pollut Barking Essex 1987, 2013, 173, 182–191, 10.1016/j.envpol.2012.09.029Suche in Google Scholar PubMed

[21] The National Research Council, A Risk Management Strategy for PCB contaminated sediments. [Internet]. Washington DC: National Academies Press; 2001, Available: https://www.nap.edu/read/10041/chapter/1Suche in Google Scholar

[22] Knox A.S., Paller M.H., Milliken C.E., Redder T.M., Wolfe J.R., Seaman J., Environmental impact of ongoing sources of metal contamination on remediated sediments. Sci. Total. Environ., 2016, 563–564, 108–117, 10.1016/j.scitotenv.2016.04.050Suche in Google Scholar PubMed

[23] Chaves L.C.C., Navoni J.A., de Morais Ferreira D., Batistuzzo de Medeiros S., Ferreira da Costa T., Petta R.A., et al., Water mutagenic potential assessment on a semiarid aquatic ecosystem under influence of heavy metals and natural radioactivity using micronuclei test. Environ. Sci. Pollut. Res. Int., 2016, 23, 7572–7581, 10.1007/s11356-015-5993-2Suche in Google Scholar PubMed

[24] de Melo Gurgel P., Navoni J.A., de Morais Ferreira D., do Amaral V.S., Ecotoxicological water assessment of an estuarine river from the Brazilian Northeast, potentially affected by industrial wastewater discharge. Sci. Total. Environ., 2016, 572, 324–332, 10.1016/j.scitotenv.2016.08.002Suche in Google Scholar PubMed

[25] Dallas H.F., Day J.A., South Africa, Water Research Commission, University of Cape Town, Freshwater Research Unit. The effect of water quality variables on riverine ecosystems: a review. Cape Town: Freshwater Research Unit, University of Cape Town, 1993.Suche in Google Scholar

[26] du Preez H.H., van Rensburg E., van Vuren J.H.J., Preliminary laboratory investigation of the bioconcentration of zinc and iron in selected tissues of the banded tilapia, Tilapia sparrmanii (Cichlidae). Bull. Environ. Contam. Toxicol., 1993, 50, 674–681, 10.1007/BF00194661Suche in Google Scholar PubMed

[27] Dallas H.F., Day J.A., Musibono D.E., Day E.G., Water quality for aquatic ecosystems: tools for evaluating regional guidelines. Water Res. Comm. Rep., 1998, 626, 98.Suche in Google Scholar

[28] Department of Water Affairs. South African water quality guidelines [Internet]. 1st ed. Pretoria, South Africa: DWAF, 1998, Available: www.iwa-network.org/filemanager-uploads/WQ_Compendium/Database/.../078.pdfSuche in Google Scholar

[29] Öztürk M., Özözen G., Minareci O., Minareci E., Determination of Heavy Metals in Fish, Water and Sediments of Avsar Dam Lake in Turkey. Iran J. Environ. Health Sci. Eng. IJEHSE, 2009, 6, 73–80.Suche in Google Scholar

[30] Odiyo J.O., Makungo R., Fluoride concentrations in groundwater and impact on human health in Siloam Village, Limpopo Province, South Africa. Water SA, 2012, 38, 731–736.10.4314/wsa.v38i5.12Suche in Google Scholar

[31] Food and Agricultural organization of United Nations. Drought impact mitigation and prevention in the Limpopo River Basin. [Internet]. Natural Resources Management and Environment Department, 2004, Available: ww.fao.org/docrep/008/y5744e/y5744e07.htmSuche in Google Scholar

[32] Edokpayi J.N., Odiyo J.O., Msagati T.A.M., Popoola E.O., Removal Efficiency of Faecal Indicator Organisms, Nutrients and Heavy Metals from a Peri-Urban Wastewater Treatment Plant in Thohoyandou, Limpopo Province, South Africa. Int. J. Environ. Res. Public Health, 2015, 12, 7300–7320, 10.3390/ijerph120707300Suche in Google Scholar PubMed PubMed Central

[33] Edokpayi J.N., Odiyo J.O., Msagati T.A.M., Potgieter N., Temporal Variations in Physico-Chemical and Microbiological Characteristics of Mvudi River, South Africa. Int. J. Environ. Res. Public Health, 2015, 12, 4128–4140, 10.3390/ijerph120404128Suche in Google Scholar PubMed PubMed Central

[34] Edokpayi J.N., Odiyo J.O., Popoola O.E., Msagati T.A.M., Assessment of Trace Metals Contamination of Surface Water and Sediment: A Case Study of Mvudi River, South Africa. Sustainability, 2016, 8, 135, 10.3390/su8020135Suche in Google Scholar

[35] US EPA O. Method 200.7: Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry [Internet]. [cited 25 Apr 2017]. Available: https://www.epa.gov/homeland-security-research/method-2007-determination-metals-and-trace-elements-water-and-wastesSuche in Google Scholar

[36] WHO. WHO | Guidelines for drinking-water quality, fourth edition. In: WHO [Internet].[cited 13 Apr 2017], Available: http://www.who.int/water_sanitation_health/publications/2011/dwq_guidelines/en/Suche in Google Scholar

[37] Fatoki O.S., Lujiza N., Ogunfowokan A.O,. Trace metal pollution in Umtata River. Water SA, 2002, 28, 183–190, 10.4314/wsa.v28i2.5160Suche in Google Scholar

[38] Singh D.A. (Ganesh), Microbial Pathogens in the Umgeni River, South Africa. Water Res Comm WRC Rep No KV 30312, Available: https://www.academia.edu/4285236/Microbial_Pathogens_in_the_Umgeni_River_South_AfricaSuche in Google Scholar

[39] Water WHO, Team S and H. WHO guidelines for drinking water quality: training pack. WHO seminar pack for drinking-water quality. 2000, Available: http://www.who.int/iris/handle/10665/66218Suche in Google Scholar

[40] Agbaire P.O., Obi C.G., Seasonal Variations of Some Physico-Chemical Properties of River Ethiope Water in Abraka, Nigeria. J. Appl. Sci. Environ. Manag., 2009, 13, 10.4314/jasem.v13i1.55265Suche in Google Scholar

[41] Vaishali P., Punita P., Assessment of seasonal variation in water quality of River Mini, at Sindhrot, Vadodara. Int. J. Environ. Sci., 2013, 3, 1424–1436.Suche in Google Scholar

[42] Benjamin A., Impact Assessment of Human Activities and Seasonal Variation on River Benue, within Makurdi Metropolis, Available: https://www.academia.edu/4532319/Impact_Assessment_of_Human_Activities_and_Seasonal_Variation_on_River_Benue_within_Makurdi_MetropolisSuche in Google Scholar

[43] Shabalala A.N., Combrinck L., McCrindle R., Effect of farming activities on seasonal variation of water quality of Bonsma Dam, KwaZulu-Natal. South Afr. J. Sci., 2013, 109, p. 7, 10.1590/sajs.2013/20120052.Suche in Google Scholar

[44] Edokpayi J.N., Odiyo J.O., Olasoji S.O., Assessment of heavy metal contamination of Dzindi River, in Limpopo Province, South Africa. Int. J. Nat. Sci. Res., 2014, 2(10), 185-194.Suche in Google Scholar

[45] South African Government Gazette. National Environmental Management Integrated Coastal Management Act, 2008. [Internet]. Pretoria, South Africa: Department of Environmental Affairs, 2011, Available: www.gov.za/sites/...za/.../38171_31-10_Act36of2014IntegratedCoastalManagem_a.p...Suche in Google Scholar

[46] Herber R.F.M., Cadmium. In: Merian E, Anke M, Ihnat M, Stoeppler M, editors. Elements and their compounds in the environment. Wiley-VCH Verlag GmbH, 2004, pp. 689–708. 10.1002/9783527619634.ch27.Suche in Google Scholar

[47] Islam M.S., Uddin M.K., Tareq S.M., Shammi M., Kamal A., Sugano T., Kurasaki M., Saito T., Tanaka S., Kuramitz H., Alteration of Water Pollution Level with the Seasonal Changes in Mean Daily Discharge in Three Main Rivers around Dhaka City, Bangladesh. Environments, 2015, 2, 280–294, 10.3390/environments2030280.Suche in Google Scholar

[48] Yao H., Qian X., Gao H., Wang Y., Xia B., Seasonal and spatial variations of heavy metals in two typical Chinese Rivers: Concentrations, environmental risks, and possible sources. Int. J. Environ. Res. Public Health, 2014, 11, 11860-11878, 10.3390/ijerph111111860.Suche in Google Scholar PubMed PubMed Central

[49] Obasohan E.E., The use of heavy metals load as an indicator of the suitability of the water and fish of Ibiekuma stream for domestic and consumption purposes. Afr. J. Biotechnol., 2008, 7(23), 4345–4348.Suche in Google Scholar

[50] Uzairu A., Okunola O.J., Wakawa R.J., Adewusi S.G., Bioavailability Studies of Metals in Surface Water of River Challawa, Nigeria. J. Appl. Chem., 2014, http://dx.doi.org/10.1155/2014/648453.10.1155/2014/648453Suche in Google Scholar

[51] Soliman N.F., Nasr S.M., Okbah M.A., Potential ecological risk of heavy metals in sediments from the Mediterranean coast, Egypt. J. Environ. Health Sci. Eng., 2015, 13, 10.1186/s40201-015-0223-x.Suche in Google Scholar PubMed PubMed Central

[52] Xu J., Wang H., Liu Y., Ma M., Zhang T., Zheng X., et al., Ecological risk assessment of heavy metals in soils surrounding oil waste disposal areas. Environ. Monit. Assess., 2016, 188, 125, 10.1007/s10661-016-5093-x.Suche in Google Scholar PubMed

Received: 2017-6-14
Accepted: 2017-9-14
Published Online: 2017-12-9

© 2017 Joshua N. Edokpayi et al.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Artikel in diesem Heft

  1. Regular Articles
  2. Rare Coumarins Induce Apoptosis, G1 Cell Block and Reduce RNA Content in HL60 Cells
  3. Regular Articles
  4. Evaluation of the photocatalytic ability of a sol-gel-derived MgO-ZrO2 oxide material
  5. Regular Articles
  6. Extraction Methods for the Isolation of Isoflavonoids from Plant Material
  7. Regular Articles
  8. Micro and nanocomposites of polybutadienebased polyurethane liners with mineral fillers and nanoclay: thermal and mechanical properties
  9. Regular Articles
  10. Effect of pH on Structural, Magnetic and FMR Properties of Hydrothermally Prepared Nano Ni Ferrite
  11. Regular Articles
  12. Statistical approach to study of lithium magnesium metaborate glasses
  13. Regular Articles
  14. The effectiveness of biodrying waste treatment in full scale reactor
  15. Regular Articles
  16. Chemical comparison of the underground parts of Valeriana officinalis and Valeriana turkestanica from Poland and Kazakhstan
  17. Regular Articles
  18. Phytochemical Characterization and Biological Evaluation of the Aqueous and Supercritical Fluid Extracts from Salvia sclareoides Brot
  19. Regular Articles
  20. Recent Microextraction Techniques for Determination and Chemical Speciation of Selenium
  21. Regular Articles
  22. Compost leachate treatment using polyaluminium chloride and nanofiltration
  23. Regular Articles
  24. Facile and Effective Synthesis of Praseodymium Tungstate Nanoparticles through an Optimized Procedure and Investigation of Photocatalytic Activity
  25. Regular Articles
  26. Computational Study on Non-linear Optical and Absorption Properties of Benzothiazole based Dyes: Tunable Electron-Withdrawing Strength and Reverse Polarity
  27. Regular Articles
  28. Comparative sorption studies of chromate by nano-and-micro sized Fe2O3 particles
  29. Regular Articles
  30. Recycling Monoethylene Glycol (MEG) from the Recirculating Waste of an Ethylene Oxide Unit
  31. Regular Articles
  32. Antimicrobial activity and thiosulfinates profile of a formulation based on Allium cepa L. extract
  33. Regular Articles
  34. The effect of catalyst precursors and conditions of preparing Pt and Pd-Pt catalysts on their activity in the oxidation of hexane
  35. Regular Articles
  36. Platinum and vanadate Bioactive Complexes of Glycoside Naringin and Phenolates
  37. Regular Articles
  38. Antimicrobial sesquiterpenoids from Laurencia obtusa Lamouroux
  39. Regular Articles
  40. Comprehensive spectroscopic (FT-IR, FT-Raman, 1H and 13C NMR) identification and computational studies on 1-acetyl-1H-indole-2,3-dione
  41. Regular Articles
  42. A combined experimental and theoretical study on vibrational and electronic properties of (5-methoxy-1H-indol-1-yl)(5-methoxy-1H-indol-2-yl)methanone
  43. Regular Articles
  44. Erratum to: Analysis of oligonucleotides by liquid chromatography with alkylamide stationary phase
  45. Regular Articles
  46. Non-isothermal Crystallization, Thermal Stability, and Mechanical Performance of Poly(L-lactic acid)/Barium Phenylphosphonate Systems
  47. Regular Articles
  48. Vortex assisted-supramolecular solvent based microextraction coupled with spectrophotometric determination of triclosan in environmental water samples
  49. Regular Articles
  50. Investigation on Two Compounds of O,O’-dithiophosphate Derivatives as Corrosion Inhibitors for Q235 Steel in Hydrochloric Acid Solution
  51. Regular Articles
  52. Evaluation of temporary seasonal variation of heavy metals and their potential ecological risk in Nzhelele River, South Africa
  53. Regular Articles
  54. Synthesis, characterization, second and third order non-linear optical properties and luminescence properties of 1,10-phenanthroline-2,9-di(carboxaldehyde phenylhydrazone) and its transition metal complexes
  55. Regular Articles
  56. Spectrodensitometric simultaneous determination of esomeprazole and domperidone in human plasma
  57. Regular Articles
  58. Computer-aided drug design of capuramycin analogues as anti-tuberculosis antibiotics by 3D-QSAR and molecular docking
  59. Regular Articles
  60. Synthesis, characterization, thermal degradation and urease inhibitory studies of the new hydrazide based Schiff base ligand 2-(2-hydroxyphenyl)-3-{[(E)-(2-hydroxyphenyl)methylidene]amino}-2,3-dihydroquinazolin-4(1H)-one
  61. Regular Articles
  62. Quaternary salts derived from 3-substituted quinuclidine as potential antioxidative and antimicrobial agents
  63. Regular Articles
  64. Bio-concentration of Polycyclic Aromatic Hydrocarbons in the grey Mangrove (Avicennia marina) along eastern coast of the Red Sea
  65. Regular Articles
  66. Quantitative Investigation of Roasting-magnetic Separation for Hematite Oolitic-ores: Mechanisms and Industrial Application
  67. Regular Articles
  68. Photobleaching characteristics of α-(8-quinolinoxy) zinc phthalocyanine, a new type of amphipathic complex
  69. Regular Articles
  70. Methane dry reforming over Ni catalysts supported on Ce–Zr oxides prepared by a route involving supercritical fluids
  71. Regular Articles
  72. Thermodynamic Compatibility, Crystallizability, Thermal, Mechanical Properties and Oil Resistance Characteristics of Nanostructure Poly (ethylene-co-methyl acrylate)/Poly(acrylonitrile-co-butadiene) Blends
  73. Regular Articles
  74. The crystal structure of compositionally homogeneous mixed ceria-zirconia oxides by high resolution X-ray and neutron diffraction methods
  75. Topical Issue on Agriculture
  76. Properties of the filtrate from treatment of pig manure by filtration method
  77. Topical Issue on Agriculture
  78. Monitoring content of cadmium, calcium, copper, iron, lead, magnesium and manganese in tea leaves by electrothermal and flame atomizer atomic absorption spectrometry
  79. Topical Issue on Catalysis
  80. Application of screen-printed carbon electrode modified with lead in stripping analysis of Cd(II)
  81. Topical Issue on Research for Natural Bioactive Products
  82. Burdock (Arctium lappa) Leaf Extracts Increase the In Vitro Antimicrobial Efficacy of Common Antibiotics on Gram-positive and Gram-negative Bacteria
  83. Topical Issue on Research for Natural Bioactive Products
  84. A survey of bacterial, fungal and plant metabolites against Aedes aegypti (Diptera: Culicidae), the vector of yellow and dengue fevers and Zika virus
  85. Topical Issue on Research for Natural Bioactive Products
  86. ‘Capiture’ plants with interesting biological activities: a case to go
  87. Topical Issue on Research for Natural Bioactive Products
  88. Volatile terpenoids as potential drug leads in Alzheimer’s disease
  89. Topical Issue on Research for Natural Bioactive Products
  90. Essential Oils as Immunomodulators: Some Examples
  91. Topical Issue on Research for Natural Bioactive Products
  92. Phenolic profiling and therapeutic potential of local flora of Azad Kashmir; In vitro enzyme inhibition and antioxidant
  93. Topical Issue on Research for Natural Bioactive Products
  94. Chemical profile, antioxidant activity and cytotoxic effect of extract from leaves of Erythrochiton brasiliensis Nees & Mart. from different regions of Europe
https://doi.org/10.1515/chem-2017-0033
Schlagwörter für diesen Artikel
Contamination factor; risk analysis; sediment contamination; seasonal variation; trace metals; human health; water quality
Creative Commons
BY-NC-ND 4.0

Artikel in diesem Heft

  1. Regular Articles
  2. Rare Coumarins Induce Apoptosis, G1 Cell Block and Reduce RNA Content in HL60 Cells
  3. Regular Articles
  4. Evaluation of the photocatalytic ability of a sol-gel-derived MgO-ZrO2 oxide material
  5. Regular Articles
  6. Extraction Methods for the Isolation of Isoflavonoids from Plant Material
  7. Regular Articles
  8. Micro and nanocomposites of polybutadienebased polyurethane liners with mineral fillers and nanoclay: thermal and mechanical properties
  9. Regular Articles
  10. Effect of pH on Structural, Magnetic and FMR Properties of Hydrothermally Prepared Nano Ni Ferrite
  11. Regular Articles
  12. Statistical approach to study of lithium magnesium metaborate glasses
  13. Regular Articles
  14. The effectiveness of biodrying waste treatment in full scale reactor
  15. Regular Articles
  16. Chemical comparison of the underground parts of Valeriana officinalis and Valeriana turkestanica from Poland and Kazakhstan
  17. Regular Articles
  18. Phytochemical Characterization and Biological Evaluation of the Aqueous and Supercritical Fluid Extracts from Salvia sclareoides Brot
  19. Regular Articles
  20. Recent Microextraction Techniques for Determination and Chemical Speciation of Selenium
  21. Regular Articles
  22. Compost leachate treatment using polyaluminium chloride and nanofiltration
  23. Regular Articles
  24. Facile and Effective Synthesis of Praseodymium Tungstate Nanoparticles through an Optimized Procedure and Investigation of Photocatalytic Activity
  25. Regular Articles
  26. Computational Study on Non-linear Optical and Absorption Properties of Benzothiazole based Dyes: Tunable Electron-Withdrawing Strength and Reverse Polarity
  27. Regular Articles
  28. Comparative sorption studies of chromate by nano-and-micro sized Fe2O3 particles
  29. Regular Articles
  30. Recycling Monoethylene Glycol (MEG) from the Recirculating Waste of an Ethylene Oxide Unit
  31. Regular Articles
  32. Antimicrobial activity and thiosulfinates profile of a formulation based on Allium cepa L. extract
  33. Regular Articles
  34. The effect of catalyst precursors and conditions of preparing Pt and Pd-Pt catalysts on their activity in the oxidation of hexane
  35. Regular Articles
  36. Platinum and vanadate Bioactive Complexes of Glycoside Naringin and Phenolates
  37. Regular Articles
  38. Antimicrobial sesquiterpenoids from Laurencia obtusa Lamouroux
  39. Regular Articles
  40. Comprehensive spectroscopic (FT-IR, FT-Raman, 1H and 13C NMR) identification and computational studies on 1-acetyl-1H-indole-2,3-dione
  41. Regular Articles
  42. A combined experimental and theoretical study on vibrational and electronic properties of (5-methoxy-1H-indol-1-yl)(5-methoxy-1H-indol-2-yl)methanone
  43. Regular Articles
  44. Erratum to: Analysis of oligonucleotides by liquid chromatography with alkylamide stationary phase
  45. Regular Articles
  46. Non-isothermal Crystallization, Thermal Stability, and Mechanical Performance of Poly(L-lactic acid)/Barium Phenylphosphonate Systems
  47. Regular Articles
  48. Vortex assisted-supramolecular solvent based microextraction coupled with spectrophotometric determination of triclosan in environmental water samples
  49. Regular Articles
  50. Investigation on Two Compounds of O,O’-dithiophosphate Derivatives as Corrosion Inhibitors for Q235 Steel in Hydrochloric Acid Solution
  51. Regular Articles
  52. Evaluation of temporary seasonal variation of heavy metals and their potential ecological risk in Nzhelele River, South Africa
  53. Regular Articles
  54. Synthesis, characterization, second and third order non-linear optical properties and luminescence properties of 1,10-phenanthroline-2,9-di(carboxaldehyde phenylhydrazone) and its transition metal complexes
  55. Regular Articles
  56. Spectrodensitometric simultaneous determination of esomeprazole and domperidone in human plasma
  57. Regular Articles
  58. Computer-aided drug design of capuramycin analogues as anti-tuberculosis antibiotics by 3D-QSAR and molecular docking
  59. Regular Articles
  60. Synthesis, characterization, thermal degradation and urease inhibitory studies of the new hydrazide based Schiff base ligand 2-(2-hydroxyphenyl)-3-{[(E)-(2-hydroxyphenyl)methylidene]amino}-2,3-dihydroquinazolin-4(1H)-one
  61. Regular Articles
  62. Quaternary salts derived from 3-substituted quinuclidine as potential antioxidative and antimicrobial agents
  63. Regular Articles
  64. Bio-concentration of Polycyclic Aromatic Hydrocarbons in the grey Mangrove (Avicennia marina) along eastern coast of the Red Sea
  65. Regular Articles
  66. Quantitative Investigation of Roasting-magnetic Separation for Hematite Oolitic-ores: Mechanisms and Industrial Application
  67. Regular Articles
  68. Photobleaching characteristics of α-(8-quinolinoxy) zinc phthalocyanine, a new type of amphipathic complex
  69. Regular Articles
  70. Methane dry reforming over Ni catalysts supported on Ce–Zr oxides prepared by a route involving supercritical fluids
  71. Regular Articles
  72. Thermodynamic Compatibility, Crystallizability, Thermal, Mechanical Properties and Oil Resistance Characteristics of Nanostructure Poly (ethylene-co-methyl acrylate)/Poly(acrylonitrile-co-butadiene) Blends
  73. Regular Articles
  74. The crystal structure of compositionally homogeneous mixed ceria-zirconia oxides by high resolution X-ray and neutron diffraction methods
  75. Topical Issue on Agriculture
  76. Properties of the filtrate from treatment of pig manure by filtration method
  77. Topical Issue on Agriculture
  78. Monitoring content of cadmium, calcium, copper, iron, lead, magnesium and manganese in tea leaves by electrothermal and flame atomizer atomic absorption spectrometry
  79. Topical Issue on Catalysis
  80. Application of screen-printed carbon electrode modified with lead in stripping analysis of Cd(II)
  81. Topical Issue on Research for Natural Bioactive Products
  82. Burdock (Arctium lappa) Leaf Extracts Increase the In Vitro Antimicrobial Efficacy of Common Antibiotics on Gram-positive and Gram-negative Bacteria
  83. Topical Issue on Research for Natural Bioactive Products
  84. A survey of bacterial, fungal and plant metabolites against Aedes aegypti (Diptera: Culicidae), the vector of yellow and dengue fevers and Zika virus
  85. Topical Issue on Research for Natural Bioactive Products
  86. ‘Capiture’ plants with interesting biological activities: a case to go
  87. Topical Issue on Research for Natural Bioactive Products
  88. Volatile terpenoids as potential drug leads in Alzheimer’s disease
  89. Topical Issue on Research for Natural Bioactive Products
  90. Essential Oils as Immunomodulators: Some Examples
  91. Topical Issue on Research for Natural Bioactive Products
  92. Phenolic profiling and therapeutic potential of local flora of Azad Kashmir; In vitro enzyme inhibition and antioxidant
  93. Topical Issue on Research for Natural Bioactive Products
  94. Chemical profile, antioxidant activity and cytotoxic effect of extract from leaves of Erythrochiton brasiliensis Nees & Mart. from different regions of Europe
Jetzt anmelden und 20% sparen
Institutioneller Zugang
Wie funktioniert Authentifizierung?
Haben Sie eine Idee, wie wir unsere Website verbessern können?
Bitte schreiben Sie uns.
© 2025 De Gruyter Brill
Heruntergeladen am 3.12.2025 von https://www.degruyterbrill.com/document/doi/10.1515/chem-2017-0033/html
Button zum nach oben scrollen