Water Quality and Trace Metal Distribution in a Pristine Lake in the Lake Basin in Kenya

Water and surface sediment samples taken from various locations within Lake Kanyaboli in the Lake Victoria basin were analysed to determine the concentration and distribution of heavy metals. There were wide ranges in concentrations of the metals among the sampling points analysed. Sediment concentrations (microg/g dry weight) ranged from n.d.-2.54 (Ag), 0.25-1.08 (Cd), 0.89-1.64 (Co), 3.7-7.73 (Cr), 1.80-30.27 (Cu), 1073-2627 (Mn), 22.61-55.60 (Ni), 11.42-153.9 (Pb), 40.46-154.7 (Sn) and 65.0-146.5 (Zn). Dissolved metal concentrations (microg/L) ranged from n.d.-9.22 (Ag), n.d.-5.54 (Cd), n.d.-8.30 (Co), 5.26-60.82 (Cr), 10.96-43.11 (Cu), 184.7-375.9 (Mn), 1.84-38.3 (Ni), 5.98-47.77 (Pb), n.d.-540.6 (Sn) and 14.5-55.9 (Zn). Compared with WHO standards and other freshwaters worldwide, this lake was found to be unpolluted, with all metals, except Mn, being detected at concentrations lower than the highest desirable levels and maximum permissible levels. Some of the toxic metals, Cu, Zn, Pb and Cd (in sediment) and Ag, Co and Pb (in water) were detected at lower concentrations than those found in the polluted Kisumu Pier in Winam Gulf in the Lake basin, which confirms the anthropogenic influence on the latter.     

Anthropogenic Sources of Heavy Metals in the Indian Ocean Coast of Kenya

Water and surface sediment samples from Rivers Sabaki, Ramisi and Vevesi that flow into the Indian Ocean coast of Kenya were analysed for heavy metals. The sediment concentrations of exchangeable cations (in μg/g) for Co, Cu, Mn, Ni, Pb, Sn and Zn ranged from 0.10 to 506.75 (for Mn at Sabaki), constituting between 2% and 20% of the total metal concentrations obtained by digestion with strong acid. Cu, Mn, Ni, Pb and Zn were more leachable with 0.1 N HCl. The total dissolved metal in water and the total sediment concentrations for Ag, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn and Zn are given in the text. For dissolved metals, the metal/Mn ratios indicated higher concentrations of Ag in Sabaki River, Cd in Ramisi, Ni in Sabaki and Pb in Ramisi, respectively. In sediments, the metal/Mn ratios showed higher enrichment of Ag in Ramisi, Cd in Sabaki and Vevesi, and Zn in Sabaki, respectively. Enrichment factors showed elevated levels of Cd, Pb and Zn in sediment in River Sabaki and River Vevesi that were due to anthropogenic inputs through Athi River. The total dissolved metal concentration ranges for the three rivers were comparable with those ranges reported in rivers in South Africa but the sediment concentrations were below those of rivers in Europe and Asia where anthropogenic addition of some of the toxic elements such as Cu, Pb and Cd is evidently higher.     

Sources of Heavy Metal Input Into Winam Gulf,Kenya

Water and surface sediment from rivers Kisat, Nyamasaria, Nyando, Sondu-Miriu, Kuja, Awach, Yala, and Nzoia, which flow into Winam Gulf, were analyzed for heavy metals in order to assess the influence of the catchment activities on heavy metal input into the lake. Sampling was done both upstream and at river mouths where the rivers entered in to the lake. The mean sediment concentration of exchangeable cations (in microg/g) for Ag, Cd, Co, Cu, Mn, Ni, Pb, Sn, and Zn ranged from 0.01 to 263 (for Mn at Kuja). Ag, Cr, and Cd were poorly leachable with 0.1 MHCl but the other cations were found to be fairly exchangeable. Most exchangeable cations in sediment ranged between 2% and 20% of the total heavy metal content obtained by digestion with strong acid. The mean total dissolved metal (0.45 microm filter cut-off) and mean total sediment concentrations ranged from nd-16 (Ag), nd-8 (Cd), nd-23.3 (Co), nd-50 (Cr), 5-157.5 (Cu), 50-3276 (Mn), nd-54.1 (Ni), 7-93.6 (Pb), 25-219.5 (Zn) in microg/L and from nd-8.34 (Ag), 0.48-1.75 (Co), nd-1.78 (Cd), 2.92-5.36 (Cr), 3.90-150.2 (Cu), 133.5-7237 (Mn), 4.33-42.29 (Ni), 3.09-66.06 (Pb), 23.39-7.83 (Sn) and 23.39-350.8 (Zn) in microg/g dry weight, respectively. The rivers analyzed were found to be non-polluted in terms of sediment loads except river Kisat which was found to be polluted because of elevated levels of Pb, Mn, Cu, and Zn. Nyamasaria and Nyando were also found to have higher concentrations of Pb, Cu, and Zn than those reported previously in the lake sediment. The dissolved metal concentrations were acceptable by WHO maximum limits in drinking water except Mn which was above WHO limit in Kisat, Nyando, and Nyamasaria waters. Enrichment of Cd and Pb was found in all the river sediment samples with factors ranging from 2.12 at Kisat river mouth to 4.41 at Awach (for Cd) and from 1.49 (at Kisat river mouth) to 2.38 (at Nyando river mouth).     

Analysis of Heavy Metals in Water and Surface Sediment in Five Rift Valley Lakes in Kenya for Assessment of Recent Increase in Anthropogenic Activities

The concentrations of heavy metals Ag, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn and Zn were analysed in water and surface sediments of five Rift Valley lakes Nakuru, Elementaita, Naivasha, Bogoria and Baringo in Kenya. The dissolved mean concentration levels (μg/L) in water ranged within 13.0–185.0 (Ag), 2.0–43.0 (Cd), 5.0–316.0 (Co), 25.0–188.0 (Cr), 4.7–100.0 (Cu), 50.0–282.0 (Mn), 19.0–288.0 (Ni), 25.0–563.0 (Pb), 300.0–1050.0 (Sn) and 29.0–235.0 (Zn). The mean sediment concentrations (in μg/g (dry weight)) ranged within 0.1–0.35 (Ag), 0.05–1.18 (Cd), 0.17–1.38 (Co), 1.94–4.91 (Cr), 1.46–20.95 (Cu), 667.7–3946.8 (Mn), 11.69–39.72 (Ni), 10.92–38.98 (Pb), 17.21–56.52 (Sn) and 96.2–229.6 (Zn). The data indicate that some of the sites analysed, especially in Lake Nakuru, had relatively higher concentration levels of heavy metals Cd, Co, Cu, Pb, Ni, and Zn in the water which points to anthropogenic addition. However, potential influence of geochemical processes on the concentration levels in sediment is also shown in Co, Ni, and Cu which were more concentrated in the remote Lake Baringo sediment as well as in Pb and Mn which were more concentrated in the remote Lake Bogoria sediment. Data on some important limnological parameters including pH, salinity, electrical conductivity and temperature are also presented.     

Accumulation and depuration of metals by duckweed (Lemna perpusilla)

Duckweed (Lemna perpusilla), inhabiting a heavy coal ash, secondary retaining basin from a coal-fired power plant, was the most abundant macrophyte sampled (occupying ～95% of the surface area) during the summer-fall period of 1979. Lemna in the basin accumulated the most abundant heavy and soft metals (Cd, Cu, Fe, Mn, Zn, Cr, Pb, Ni) affiliated with heavy ash to a greater extent than found in water or coal ash sediment. After a 14-day holding period under laboratory conditions of low metal influence, some duckweed metal concentrations declined to levels similar to those found in the ash basin sediments (Pb, Cr, Ni, and Cu), while other tissue concentrations (Cd, Zn, Mn, and Fe) remained higher. During the 10-day laboratory exposure bioassay (concentrations of 0.5, 1, 10, 25, and 100 times those measured in the basin for all metals) after the depuration period, high duckweed mortality was evident within 2 to 10 days at concentrations of 10× and higher, which were coupled with excessive pH reduction (3.6-2.6). Significant accumulation relative to conditions in the ash basin occurred at ≥10× concentration (≥0.50 and 0.10 mg/liter, respectively) for Pb and Cr and at the 1× level (0.10 mg/liter) for Ni. Depuration concentrations returned to control levels within 8 days. Cu and Cd showed similar high increases (～1200 and 100 mg/liter, respectively) in bioconcentration during the 0.5 to 1.0 × concentrations but failed to be significantly depurated during the 8-day recovery period. Exposures to 0.10 mg/liter Zn and 0.05 mg/liter Mn failed to show depuration to levels similar to the control concentrations. The capacity of duckweed to accumulate potentially toxic heavy metals in coal-ash-retaining systems may have an important role upon the displacement of these elements on a seasonal basis. Aquatic elemental releases of duckweed may be minimal during the growing season due to the bioconcentration capability but can be maximal in the fall during the process of natural mortality and the resulting depuration process into the receiving drainage system.     

Comparison of heavy metals in marine sediments from coast areas in East and Southeast Asian countries during the years 2000--2010

Comparisons of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) in marine sediments from coast areas in Southeast and East Asian countries during the years 2000-2010 are studied and discussed in this paper. The results indicate that the average compositions of Cd ranged from 0.13 to 0.89 mg/kg, and the average compositions of Cr ranged from 0.09 to 96.0 mg/kg. Moreover, the average compositions of Cu ranged from 3.00 to 148 mg/kg, and the average compositions of Ni ranged from 1.00 to 37.4 mg/kg. In addition, the average compositions of Pb ranged from 1.00 to 111 mg/kg. Finally, the average compositions of Zn ranged from 4.00 to 595 mg/kg. From the point of view of metals distribution areas for this study, the average highest metal of Ni occurred in East Asia, while the highest metals of Cd, Cr, Cu, Pb, and Zn occurred in Southeast Asian countries.     

Metal Contamination in Market Based Vegetables in an Industrial Region, India

Concentrations of metals were determined in market vegetables in Ghaziabad industrial region. The average concentrations of metals (mg/kg dry wt.) in vegetables ranged from 0.57 to 9.77, 0.72 to 22.17, 2.76 to 46.63, 2.53 to 5.53, 28.87 to 65.94, 6.77 to 74.1, 8.43 to 161.1, 23.46 to 36.55 and 4.74 to 24.18 for Cu, Cr, Pb, Cd, Zn, Mn, Fe, Ni and Co, respectively. Pb, Cd and Ni were above the recommended limit in all the examined vegetables.     

Uptake of lead, cadmium, and other metals in the liver and kidneys of cattle near a lead-zinc mine in Kabwe, Zambia

Concentrations of lead, cadmium, and other metals in the liver and kidneys of cattle near a lead-zinc mine in Kabwe (Zambia), which is ranked among the 10 worst polluted places on earth, were compared with other Zambian towns. Metal concentrations were measured in the liver and kidneys of 51 cattle from Kabwe and other Zambian towns. The maximum metal concentrations, expressed in mg/kg and dry weight, in the liver or kidneys were 398.4 (Cu), 252.6 (Zn), 77.81 (Cr), 19.37 (Cd), 7.57 (Ni), 1.8 (Pb), 1.04 (Co), 0.112 (Hg), and 0.05 (As). Concentrations of Pb and Cd in Kabwe cattle were higher than levels in other Zambian towns. The mean concentration of Cd exceeded benchmark values in offal destined for human consumption. Levels of Ni and Cr may also pose public health concerns. Concentrations of Pb and Cr, Pb and Cu, Cd and Zn, Cd and Hg, Zn and Cu, Cu and Co, as well as Co and Ni were positively correlated. The present study also highlighted the dangers of exposure of animals and humans to a mixture of toxic metals.     

Heavy Metals in Normal Japanese Tissues

? To obtain the usual values of arsenic, beryllium, bismuth, cadmium, chromium, cobalt, copper, mercury, methyl mercury, manganese, molybdenum, nickel, lead, antimony, vanadium, and zinc in the normal human body, the amounts of 15 metals were determined in 15 male and 15 female Japanese cadavers (average weight, 55 kg [121 lb]). The content of metals found ranged as follows: Zn, 1,800 mg; Cu, 65 mg; Cd, 35 mg; Pb, 25 mg; Mn, 8 mg; Ni, 6 mg; Cr, 4 mg; Hg, 3 mg; Sb, 0.7 mg; MeHg, 0.4 mg.

Cadmium and mercury were higher in Japanese blood than in blood of other people. Cadmium and mercury were absorbed by the metabolic tissues; Cr, Ni, and Pb showed higher concentration in tissue exposed to the environment. Concentrations of Cd, Pb, and Hg tended to be higher in females, and Cr, Cu, MeHg, and Mn concentrations tended to be higher in males.     

Toxic metals in aquatic plants surviving in surface water polluted by copper mining industry

Concentrations of the metals Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn, as well as the macronutrients N, P, K, Ca, Mg, and S were measured in water, sediments, and the aquatic macrophytes Potamogeton pectinatus and Myriophyllum spicatum, growing in surface water receiving sewages and solid wastes from a copper smelter and a copper ore processing factory located in the Legnica-Glogow copper district in Southwest Poland. The deposition of mineral wastes in this area belong to the largest repository in Europe. The plants were able to survive at heavily contaminated sites. The concentrations of Cd (up to 0.6-1.7 microg/L in water and up to 10.1-12.9 mg/kg in sediments), Cu (up to 29-48 microg/L in water and up to 4.6-5.6g/kg in sediments), Pb (up to 1.5-2.2 g/kg in sediments), and Zn (up to 167-200 microg/L in water and up to 1.4-1.8 g/kg in sediments) seriously exceeded background values. P. pectinatus was able to survive tissue concentrations (in mg/kg) of up to 920 Cu, 6240 Mn, 98 Co, and 59 Ni, while M. spicatum survived tissue concentrations up to 1040 Cu, 6660 Mn, and 57 Co for. Enrichment ratios of elements in plant tissue and in water were much higher than those between plant tissue and sediments.     

Heavy metals in aquatic bryophytes from the Ore mountains (Germany)

Concentration of the metals Ni, Cr, Co, Zn, Mn, Pb, Cd, Cu, Ba, Al, and V as well as the macronutrients Ca, Mg, and K were measured in water and in the aquatic bryophytes Platyhypnidium riparioides, Scapania sp., and Fontinalis antipyretica sampled from streams in the Erzgebirge (Ore Mountains, eastern Germany). These plants, as used to evaluate the spatial distribution of elements in the examined streams, contained elevated levels of all the investigated metals except Sr. The highest levels of Cd (195 mg/kg), Cu (233 mg/kg), Zn (22500 mg/kg), Pb (595 mg/kg), and Co (140 mg/kg) seriously exceed background values. In recent years input of pollutants has decreased in the Erzgebirge area and the deposition can now be addressed as being comparable to that of rural areas without major local or regional influences. This investigation indicates that the studied aquatic mosses reflect part of the pollutant loadings released in the past in the Erzgebirge area of which remnants are still present in the environment. Two models describing the con-centrations of Fe and Zn in aquatic bryophytes in relation to concentrations of some elements in water are presented.     

Toxicity of eight metals to Malaysian freshwater midge larvae Chironomus javanus (Diptera, Chironomidae)

Fourth instars larvae of freshwater midge Chironomus javanus (Diptera, Chironomidae) were exposed for a 4-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al) and manganese (Mn) concentrations. Mortality was assessed and median lethal concentrations (LC(50)) were calculated. LC(50) increased with the decrease in mean exposure times, for all metals. LC(50)s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al and Mn were 0.17, 0.06, 5.57, 0.72, 5.32, 0.62, 1.43 and 5.27 mg/L, respectively. Metals bioconcentration in C. javanus increases with exposure to increasing concentrations and Cd was the most toxic to C. javanus, followed by Cu, Fe, Pb, Al, Mn, Zn and Ni (Cd > Cu > Fe > Pb > Al > Mn > Zn > Ni). Comparison of LC(50) values for metals for this species with those for other freshwater midges reveals that C. javanus is equally or more sensitive to metals than most other tested dipteran.     

Distribution of Metals in Surface Sediments from a Small River Flowing Through Urban and Agricultural Areas

The characteristic distributions of 12 metals (Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Cd and Pb) were investigated in surface sediments from a small river (Niitsu River) flowing through both urban and agricultural areas by comparison with those from the upper main stream (Nodai River). Among the investigated metals, the mean concentrations of Al, Cr, Fe, Zn, Cd and Pb in the Niitsu River were significantly higher than those in the Nodai River. The investigated sites can be characterized by the principal components 1–3.     

Bioaccumulation of heavy metals in mullet (Mugil cephalus) and oyster (Crassostrea madrasensis) from Pulicat lake, south east coast of India

The accumulation of six heavy metals (Cr, Cd, Cu, Zn, Pb and Ni) in sediment, water and in tissue parts of Mugil cephalus and Crassostrea madrasensis was studied in two locations of Pulicat lake, Southeast coast of India, which receives considerable quantity of effluents from industries located in North Chennai coastal region. The results reveal that the metal concentration in water is decreasing in the following order of Zn > Ni > Cu > Cr > Pb > Cd both in lake and barmouth and highest concentration was observed for Zn (32.5 μg L(-1) in lake and 25.2 μg L(-1) in bar mouth). Metals were highly concentrated in sediments when compared to water and biota. Metals abundance in sediments has following sequential order of Cr > Ni > Zn > Cu > Pb > Cd and the accumulation pattern in barmouth showed minor variation indicating the following pattern of Zn > Ni > Cr > Cu > Pb > Cd. The geoaccumulation index (I(geo)) for Pulicat lake sediments indicate that the sediments are extremely contaminated with Cd and moderately contaminated with Cu and Ni. Bioaccumulation of heavy metals in Mugil cephalus and Crassostrea madrasensis showed marked differences in the accumulation patterns. It is observed that Zn, Cu and Pb are accumulated in elevated concentrations in various parts of the fish and oyster when compared with other metals.     

Monitoring Trace Metal Contaminants in Green Mussel, Perna viridis from the Coastal Waters of Karnataka, Southwest Coast of India

The green mussel (Perna viridis) is widely distributed in the coastal waters of Asia and is used in mussel watch programmes for monitoring environmental contaminants throughout the region. Green mussels representing different size groups and habitats were sampled from their natural beds at 28 locations in the inshore waters of Karnataka (southwest coast of India) to analyze the tissue concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Tissue concentrations of Cr, Cu, Fe, and Pb were significantly higher in smaller mussels than in the larger size group. Significantly higher concentrations of Cr, Cu, Fe, Mn, and Ni were observed in mussels sampled from intertidal beds when compared to mussels from the subtidal beds. The sampling sites were categorized into industrial sites (IS), urban sites (US), and nonurban sites (NS) based on principal component analysis of metal concentrations in mussel. Spatial variations in tissue concentrations of all metals were observed except for Zn. Generally, the levels of toxic trace metals like Pb, Cd, Ni, and Cr in the whole tissue of P. viridis were within safe limits throughout the coast of Karnataka. However, relatively high concentrations of Cd, Cr, and Pb were observed in the whole tissue of green mussels collected from the industrial sites (IS), which may be derived from a variety of anthropogenic activities.     

Heavy metals in normal Japanese tissues. Amounts of 15 heavy metals in 30 subjects.

To obtain the usual values of arsenic, beryllium, bismuth, cadmium, chromium, cobalt, copper, mercury, methyl mercury, manganese, molybdenum, nickel, lead, antimony, vanadium, and zinc in the normal human body, the amounts of 15 metals were determined in 15 male and 15 female Japanese cadavers (average weight, 55 kg [121 lb]). The content of metals found ranged as follows: Zn, 1,800 mg; Cu, 65 mg; Cd, 35 mg; Pb, 25 mg; Mn, 8 mg; Ni, 6 mg; Cr, 4 mg; Hg, 3 mg; Sb, 0.7 mg; MeHg, 0.4 mg. Cadmium and mercury were higher in Japanese blood than in blood of other people. Cadmium and mercury were absorbed by the metabolic tissues; Cr, Ni, and Pb showed higher concentration in tissue exposed to the environment. Concentrations of Cd, Pb, and Hg tended to be higher in females, and Cr Cu, MeHg, and Mn concentrations tended to be higher in males.     

Heavy metals in three lakes in West Poland.

Concentrations of heavy metals (Ni, Cr, Co, Zn, Mn, Pb, Cd, Cu, Hg, Fe) as well as macronutrients (P, Ca, Mg) were measured in water, bottom sediments, and plants of three lakes in West Poland (southwest of Poznan). The plants collected were Nymphaea alba, Nuphar luteum, Ceratophyllum demersum, Phragmites communis, Typha latifolia, and Schoenoplectus lacustris. These plants contained elevated levels of Co, Zn, Pb, Cd, Cr, and Hg. Analyses of water and bottom sediments indicated that the lakes were polluted with Zn, Cd, Cu, and Pb and partly with Ni and Hg. Strong positive correlations were found between concentrations of Cd in water and in plants, between concentrations of Cd in bottom sediments and in plants, between concentrations of Cr in water and in plants, between concentrations of Cr in bottom sediments and in plants, and between concentrations of Fe in water and in plants, indicating the potential of plants for pollution monitoring for these metals. A negative correlation was found between biomass production and Pb and Mn content in water and Pb and Mn content in bottom sediments. Cr and Cd accumulated in plants at a higher rate from bottom sediments than from water. The accumulation rate of Fe in plant tissues was higher with an increase in Fe in water than with an increase in Fe in bottom sediments.     

Metal Concentrations of Common Freshwater and Marine Fish from the Pearl River Delta,South China

Sediments and fish, including tilapia (Oreochromis mossambicus), bighead carp (Aristichthys nobilis), grass carp (Ctenopharyngodon idellus), and mandarin fish (Siniperca chuatsi) were collected from different fish ponds in the Pearl River Delta (Tanzhou, Sanjiao, Guangzhou, Shipai, Changan, and Mai Po) for the analysis of metalloids and heavy metals [arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb)]. The pollution of As in pond sediments was great; however, As in the edible parts of pond fish were within the international permissible safety levels for human consumption. Axial muscles from 10 species each of freshwater and marine fish purchased from markets in Hong Kong were also analyzed for As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. Freshwater fish contained 0.24 to 2.13 mg/kg As, 0.10 to 0.17 mg/kg Cd, 0.09 to 0.36 mg/kg Cr, 0.06 to 0.35 mg/kg Cu, 0.07 to 0.34 mg/kg Hg, 0.04 to 0.36 mg/kg Ni, 0.11 to 0.52 mg/kg Pb, and 2.67 to 19.1 mg/kg Zn (wet weight). Marine fish had higher Hg and lower Pb concentrations than freshwater fish. A few fish species had average concentrations greater than the international standards for Cd and Pb established by the European Union and the China National Standard Management Department. Total Hg concentrations in 10 of 20 market fish species were generally greater than those of the World Health Organization’s recommended limit of 0.2 mg/kg for at-risk groups, such as children and pregnant women. Daily intake through fish consumption of these metals were compared with the Provisional Tolerable Weekly Intake proposed by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives. There appears to be potential threat to local people from Hg contamination because of the high marine fish consumption rate (142 g/d/person).     

Pulmonary metal distribution in urban dwellers

To clarify the factors influencing the concentrations and distribution of metal elements in the lung, we analyzed the following 8 metals in the 5 lung lobes of 17 autopsied urban dwellers by flame or flameless atomic absorption spectrometry: aluminum (Al), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), manganese (Mn), copper (Cu), and Zinc (Zn). The arithmetic mean value (in micrograms of metal per gram of dry weight) calculated for five lobar metal concentrations in each subject ranged from 80 to 681 for Al, from 0.34 to 3.41 for Cd, from 0.41 to 12.7 for Cr, from 0.22 to 1.93 for Ni, from 0.15 to 1.47 for Pb, from 0.64 to 2.36 for Mn, from 2.84 to 7.24 for Cu, and from 40.7 to 77.6 for Zn. The eight metals were classifiable into two groups on the basis of the interindividual and interlobar concentration variations. The first group, consisting of Cu and Zn, was characterized by smaller interindividual variations (coefficient of variation, CV < 30%) and smaller inter lobar variations (mean CV < 15%). Their levels were not affected significantly by sex, smoking habits, or possible occupational exposure to metal-containing dust. In contrast, the second group, consisting of Al, Cd, Cr, Ni, Pb, and Mn, exhibited larger interindividual variations (CV > 45%) and larger interlobar variations (mean CV > 25%). Concentrations of these metals, except for Cd, tended to be higher in the upper lobes than in the lower lobes. The concentrations of Al and Cr were significantly higher in men than in women. Smoking significantly elevated the levels of Cr, Cd, Ni, and Pb, and the concentrations of Al, Cr, Ni, and Mn were higher in subjects with possible occupational exposure to metal-containing dust than in those without such exposure. However, the interlobar distribution patterns of the metals did not seem to be influenced by sex, smoking habits, or occupational exposure to metal-containing dust. Received: 18 March 1996 / Accepted: 2 January 1997     

Heavy-Metal Levels in Feathers of Cattle Egret and Their Surrounding Environment: A Case of the Punjab Province, Pakistan

Levels of 10 heavy metals in cattle egret chick feathers, prey, and surrounding soils from three heronries in Punjab Province, Pakistan, were assessed by atomic absorption spectrophotometry. Mean levels of cadmium (Cd), iron (Fe), chromium (Cr), and lithium (Li) in feathers, manganese (Mn), cobalt (Co), and nickel (Ni) in prey, and lead (Pb), iron (Fe), chromium (Cr), zinc (Zn), cobalt (Co), and lithium (Li) in soils were significantly different among Trimun Headworks, Shorkot, and Mailsi heroneries. Mean levels of Pb (43.10 μg/g), Cr (35.77 μg/g), Co (18.34 μg/g), Cu (0.20 μg/g), and Ni (0.22 μg/g) in feathers were significantly greater at Mailsi, and Mn (3.07 μg/g), Zn (18.83 μg/g), and Li (1.5 μg/g) levels were significantly greater at Shorkot. Multivariate analysis identified that some metals, such as Fe, Zn, and Li, in feathers were either associated with natural sources or with human-related activities, whereas Ni, Cr, Pb, Cd, Cu, Co, and Mn were correlated mainly with anthropogenic processes. Alarming levels were recorded for Cr, Pb, and Cd in feathers that were above threshold levels that may affect cattle egret flighting capacity and reproduction, thus leading to their population decline in Punjab Province. The results of this study provide evidence for the potential of feathers of cattle egret to be used as a biomonitor for the local heavy-metal contamination.