الفهرس Only 14 pages are availabe for public view
 |  | from | 229 |  |  |
| | | from | 229 | | |
Abstract
Summary
The River Nile, the principal freshwater resource of irrigation, industrial and domestic water, facing major environmental problems associated with the dispersal or disposal of some hazardous industrial and urban wastes generated by human activities.
Perfluorochemicals (PFCs) and heavy metals are chemical pollutants which proved to cause serious problems in our environment, fish and other aquatic organisms, birds and animals as well as humans owing to their toxicity, persistence and bioaccumulation. PFCs are unusual chemicals having both hyDROPhobic and lipophobic characters and contain one of the strongest chemical bonds (C-F) known (110kcal/mol) which make the compounds highly stable in the environment and become desirable for commercial use in wide variety of applications since 1950s.
The study considered the basic view devoting the existence of PFCs and extent of heavy metals pollution to River Nile water and its main branches in Egypt. Fifty one sites along Egypt were chosen from the main stream of the River Nile, Damietta, and Rosetta branches, Ibrahimiya and Sohagia branches in addition to some of minor branches. Three samples, from each site, were pooled, filtrated and separated into two parts.
One liter of water sample was subjected to solid phase extraction using WAX cartilage and analyzed using Ultra Performance Liquid Chromatography (UPLC) and tandem mass spectrometry (MS/MS) for fifteen PFCs detection, including Perfluorobutane sulfonate (PFBuS), Perfluorohexane sulfonate (PFHxS) Perfluorooctane sulfonate (PFOS), Perfluorodecanesulfonate (PFDS), 6:2 Fluorotelomer sulfonate (6:2 FTS), Perfluoropentanoic acid (PFPeA), Perfluorohexanoic acid (PFHxA), Perfluoroheptanoic acid (PFHpA), Perfluorooctanoic acid (PFOA), Perfluorononanoic acid (PFNA), Perfluorodecanoic acid (PFDA), Perfluoroundecanoic acid (PFUnDA), Perfluorododecanoic acid (PFDoDA), Perfluorotridecanoic acid (PFTrDA) and Perfluorotetradecanoic acid (PFTeDA).
One hundred milliliters were utilized for quantitative estimation of heavy metals including; Iron (Fe), Manganese (Mn), Copper (Cu), Zink (Zn), Lead (Pb), Cadmium (Cd), Nickel (Ni) and Chromium (Cr) using atomic absorption spectrophotometer (GBC 906, Australia) and different cathode lamps with air acetylene flame method.
A. For Perfluorinated compounds (PFCs) analysis
PFOA and PFOS were the only detected compounds from the examined PFCs ranging from 257- 2377 pg/l and <36- 188 pg/l from Rosetta branch and <100- 433 pg/l and <36- 145 pg/l from Damietta branch, <100-491 and <36-211 pg/l from Ibrahimiya branch and <100-700 pg/l and <36- 531 pg/l from the main stream, respectively.
PFOA was quantified from 93.5% of the water samples at concentrations ranging between 127-2377 pg/l. The highest recorded PFOA, among all sites with thousands of Pico grams, was 2377 pg/l from GH5 in Kafr El-Zayat (Gharbia Governorate) which was 2 fold higher than the following site MF3 (1551 pg/l) from Mounofia, both from Rosetta branch. On the other hand both locations contained trace levels (<MDL) of other PFCs (even for PFOS). This pattern might indicate that Mounofia and Gharbia Governorates had subjected to similar sources of fluorochemical contamination which only involved PFOA.
Industrial activities in Kafr El-Zayat for insecticides, phosphate fertilizers and Sodium fluosilicate, paper mill, oil refining, soup, cosmetics and cleaners production as well as domestic and municipal sources from Monufia Governorates could be recognized as significant point source(s) of PFCs, which discharge their wastes directly to the aquatic environment. Meanwhile, downstream of the previous mentioned location, the MF2 (302 pg/l) location showed a concentration 5 fold lower than from MF3 (1551 pg/l) suggesting a self-cleaning capacity of the Nile which may be resulted from good water circulation and current.
The degree of pollution with PFOA from upstream (south to north) of the River Nile was relatively low (303 ±162.6 pg/l) until its divergence to Rosetta and Damietta branches in Qalyubia. The concentrations had increased considerably at Rosetta branch only (805±773.1 pg/l), indicating the presence of pollution source(s) of the compound leaching directly into the branch. However, PFOA concentrations declined gradually at Damietta branch (260 ±127.3) which might be attributed to the dilution as the water mass increased downstream or lack of point source(s). However, the mean concentration of PFOA were 296 ± 20.3 pg/l from Sohagia branch and 270 ± 151.6 pg/l from Ibrahimiya branch
Detected concentrations of PFOS, above the limit of detection (<36 pg/l), were observed in 41.3% of the sampling sites with a concentration ranging between 39 and 531 pg/l. PFOS concentration started to increase gradually from Qena (85 pg/l) to reach its highest level in Assiut (531 pg/l) then abruptly decreased in Minya (<MDL) then slightly increased again at Sixth of October (211 pg/l) and Monufia (188 pg/l) Governorates. The highest level in Assiut assumed to be resulted from diffuse emissions of PFCs and atmospheric transport followed by dry and wet deposition on the surface water. The pollution source could be attributed to the vast agricultural activities as well as industrial emissions from cement, fertilizers and oil refinement medications, which carried by the wind from potential emission sources and transported pathways in the aqueous environment.
Lower levels of PFOS (<100 pg/l) were recognized in 66.6% of the detected samples of the present study. However, those found below the detection limits (<36 pg/l) were at percentage of 50% of the analyzed samples that distributed as 61% from the main stream, 13% from each of Ibrahimiya and Rosetta branch, 9% from Damietta branch and 4% from Sohagia branch.
It was noticed that the detection percentage and the composition profiles of PFCs was dominant by PFOA followed by PFOS which could be attributed to higher production and use of PFOA, including fluoropolymer manufacturing, higher water solubility of PFOA, lower bioaccumulation potential and lower sorption potential to sediment in comparison to PFOS might be responsible for increasing its emission to the environment
The present investigation revealed that Rosetta branch had the highest PFCs contributions for both PFOA and PFOS. Elevated PFCs concentration downstream of the river; suggesting point sources and/or the discharge volume probably overwhelmed the dilution effect at the downstream sites.
A safe level of drinking water equivalent level (DWEL) reported a non cancer range for PFOA between 0.88- 2.4 µg/l. However, 50 ng/l has been determined to be a protective of trophic level IV avian species for PFOS. Compared with PFOA and PFOS risk-based levels values, the concentrations in presnt water samples from Egypt were much lower. Therefore, the relevant level did not pose any significant adverse health effect to aquatic organisms, birds, animals and humans at this point in time.
B. For heavy metals analysis
In the 17 river water samples that collected from the Nile Delta Governorates. Fe, Mn and Zn were detected in all of the water samples in the range of 0.167–1.115, 0.016- 0.126 and 0.019 – 0.225 mg/l, respectively. The other metals, viz. Cu, Pb, Cd and Cr were found in 76.5%, 64.7%, 94.1%and 52.9% of samples in the range of 0–0.169, 0- 0.373, 0- 0.035and 0- 0.403 mg/l, respectively. However, Ni was detected in only 11.8% of the samples analyzed in a range 0- 0.079 mg/l. However, from river water samples collected from Governorates around Cairo (16 samples), the concentration of various heavy metals that represented by. Fe, Cu and Zn were detected in all water samples in the range of 0.189-14.98, 0.002- 0.145 and 0.065-0.296 mg/l, respectively. The other metals, viz. Mn, Pb and, Cd were found in 75%, 68.8% and 87.5% of samples in the range of 0–3.89, 0-1.612 and 0- 0.03 mg/l, respectively. However, Ni and Cr were detected in only 25% and 12.5% of the analyzed samples in a range 0- 0.083 and 0- 0.306 mg/l, respectively. In the tested 18 river water samples that collected from Governorates of Upper Egypt, the concentration of various heavy metals. Fe, Zn and Pb were detected in all of the water samples in the range of 0.062- 0.463, 0.068-0.535 and 0.041- 0.183 mg/l, respectively. The other metals, viz. Mn, Cu, Cd and Cr were found in 55.6 %, 88.9%, 94.4% and 61.1% of samples in the range 0- 0.084, 0- 0.019, 0- 0.183, 0- 0.018 and 0-0.043 mg/l, respectively. However, Cr was detected in only 16.7 % of the analyzed samples in a range 0- 0.136 mg/l.
The highest Fe concentration among all sites (14.98 mg/l) was observed at HW4 (Helwan Governorate), which was 14 fold higher than the following sites by GH4 and GH5 sites (both from Gharbia Governorate). Fe concentrations from water samples in Helwan governorate were 4 times higher than that detected in Behiera governorate. This could be attributed to that Helwan is one of the biggest industrial zones in Egypt that encompass many factories for iron, steel, textile and cement industries which have a direct discharge of their wastewater from steel plants as well as the runoff from agricultural areas as well as the intensive use of iron based fertilizers. The Egyptian (MHP), American (EPA) and European (EC) guidelines for Fe were exceeded at 53%, 53% and 73% of the water samples of the present study, respectively.
Maximum value of Mn among all sites (3.894 mg/l) was reported at HW4 (Helwan Governorate) which was 26 fold higher than the following concentration from OC1 and GH4 (Sixth of October and Gharbia Governorates), respectively. On comparing Mn values throughout the studied Governorates, results showed that the highest level was recorded in water samples collected from Helwan Governorate (0.981 mg/l). High level probably from natural source or such sites may my liable to anthropogenic activities which release Mn, as industrial effluents from ore and steel industry, as well as agricultural runoff from fertilizers, sewage sludge and animal waste. River water samples showed higher concentrations of Mn when compared to the MHP, WHO, EPA and EC standards at 2, 2, 45 and 45% of the water samples collected.
At all the sampling sites Cu and Zn were determined in small concentrations in the river water and were below the permissible limits for drinking water guidelines of the MHP, WHO, EPA and EC. Accordingly, the relevant concentration in this study did not possess a significant health hazards to human, animal or aquatic life.
The maximum Pb concentration in the water was obtained from HW2 site (1.612 mg/l) at Helwan Governorate followed by GH2 and OC4 sites (0.362 mg/l each) from Gharbia and Sixth of October Governorates, respectively. Higher Pb values in such sites could be resulted from wide spread industrial production of paints, solders, pottery glazers, rubbers, plastics, insecticides, batteries, shots and ammunitions, caulking materials, cable sheathings and lead pipes and release of its effluents into the water bodies without sufficient treatment. Interestingly, the lowest detected Pb levels were higher than those reported in the drinking water guidelines of the MHP, WHO and EC (0.01 mg/l), which exceeded in 78.4% of the collected samples.
Results of the present study pointed out that, the current Pb levels in River Nile could have a threat to aquatic life (including fish and shrimp), plant, animal and human life. Such higher concentration of Pb, drawing the attention of the importance of adequate water treatment using slaked lime or activated carbon filter for effective treatment of heavy metals in river water.
Highest Cd concentrations among all sites were 0.035 mg/l (BT1) at Damietta Governorate and 0.03 mg/l at QB2 and Qalyubia Governorate followed by GH9 and GH8 sites (both from Gharbia Governorate) at concentrations of 0.022 and 0.021 mg/l, respectively. It is possible that the high concentration of Cd is existed in such governorates due to anthropogenic sources; include sewage sludge, agricultural and urban storm-water runoff, mining, smelting, textile manufacture, waste incineration and tobacco smoke
The mean levels of Cd recorded varied between 0.035 mg/l and 0.001 mg/l, which was above the MHP, WHO and EC in 86%, 86% and 67 %, respectively. On the other hand, none of the sample concentration exceeded the values recommended of the EPA water quality
The maximum Ni concentration among all sites was 0.083 mg/l from HW3 site (Helwan Governorate) followed by 0.079 mg/l from GH3 (Gharbia Governorate). On the other hand, the minimum detected concentration was observed from QB1 site (0.001 mg/l) from Qalyubia Governorate followed by BS3 site (0.002 mg/l) from Beni-Suef Governorate and SG1 site (0.003 mg/l) from Sohag Governorate. Water samples, collected in the present study, showed higher concentration of Ni when compared to the WHO, MHP and EC at 3.9% 16 % and 16% of the samples, respectively.
Although Damietta Governorate had the lowest level of the total heavy metal contents in the river water samples, concentration of Cd and Ni was the highest among all sites. This indicates that Damietta may be locally around known industrial pollution source (s) as paints, dyes, rubbers and candles, alloy processing, batteries and cement industries.
The highest observed Cr level was 0.403 mg/l from BH1 site (Beheira Governorate) followed by 0.306 mg/l from both GH5 and OC3 (Gharbia and Sixth of October Governorate) and 0.285 mg/l from DK1 (Dakahlia Governorate). Although the frequency of Cr was low (27%) in the examined water samples, Cr was found to go beyond the recommended guideline limits of MHP, WHO and EC (0.05 mg/l each) and EPA (0.1 mg/l) for domestic water at most of the samples detected. Cr level exceeded the previously mentioned standard limits at 41%, 6% and 11% in the river water samples from Governorates of Nile Delta, around Cairo and Upper Egypt, respectively.
Generally, it was difficult to identify an organized pattern for any particular metal concentration throughout the examined water samples. In addition, temporal variations of metal concentrations showed evidence of the water self-cleaning capacity of the River Nile, despite the high-level metal contamination determined from some locations. Although, River Nile receives considerable amounts of untreated domestic and industrial effluents that affect directly the water quality, but it can suggest that River Nile has an intense self-purification capacity.
The highest level of Fe and Mn, in this study, was observed from HW4 location (Helwan). In addition, Cu and Zn were the second and third highest concentration detected all over the water samples gathered in Egypt. This could be due to Fe may be largely colloidal in this part of the River Nile or as a result of the direct effluent discharge of steel industry into the main stream of the River Nile at Tabbin district. However, increasing the heavy metal concentration from such site indicated that gross pollution of the River Nile possess a health risk to plant, animal and human life in the area and the elevated level of heavy metals in the waters is related to man-induced pollution as a result of sewage discharge into the water. Generally, heavy metals concentrations in the water samples examined were decreased in sequence of Fe > Pb > Cr > Mn > Zn > Ni > Cu > Cd.
The present investigation showed that, there was considerable variation in the concentration of elements from one sampling site to anther which might be due to the variation in the quality of industrial and sewage wastes being added to the river at different sampling sites.
Pearson Correlation Coefficient (parametric) between different heavy metals in the main stream of the River Nile, revealed a positive correlation between Fe and Mn (r= 0.9981**) and Cu (r= 0.9908**) and between Mn and Cu (r= 0.9883**). However, heavy metals from Rosetta branch, showed correlations between the same previous metals (r= 0.8158*, 0.9664** and 0.8114*, respectively. A significant correlation between Cu and Cd (r= 0.8384*) in Damietta branch was observed indicate either their common urban origin or their common sink in the stream sediments. However, Analysis of variance for metals from Ibrahimiya canal revealed no significant effect on the occurrence of these metals in the canal. Absence of correlations between most of the studied metals may prove the presence of different sources for the input of heavy metals to River Nile and its branches.