An Assessment of Heavy Metal Contamination in Vegetables Grown in Wastewater-Irrigated Areas of Titagarh,West Bengal,India

The effects of municipal wastewater irrigation on the accumulation of heavy metals (Pb, Zn, Cd, Cr, Cu and Ni) in soil and vegetables were investigated by monitoring wastewater-irrigated agricultural field of Titagarh, 24-Parganas (North), West Bengal, India. The mean concentrations of Pb, Ni, Cu in the irrigation water and the mean Cd content in soil were much above the recommended level. The concentrations of Pb, Zn, Cd, Cr and Ni in all the examined vegetables were beyond the safe limits. The study reveals that heavy metal-contaminated vegetables grown in wastewater-irrigated areas may pose public health hazards.     

公路旁土壤中重金属污染分布及潜在生态危害的研究

[目的]研究公路旁土壤中重金属污染的分布及潜在生态危害。[方法]以319国道龙岩市新罗区路段为研究区,对耕作土采样,用原子吸收光谱法和分光光度法分析土壤中重金属Cd、Pb、Cu、Zn和Cr含量,并与对照区比较,同时采用Lars Hakanson指数法评价重金属的潜在生态危害。[结果]研究区表层土壤cd[(1.48±0.60)mg/kg]、Pb[(160.17±55.99)mg/kg]、cu[(38.44±12.16)mg/kg]、Zn[(80.35±6.60)mg/kg]、Cr[(79.50±23.58)mg/kg]含量显著高于对照区(P<0.001),Cd和Pb为重度污染(100％),Cu和Cr为轻微污染(分别占监测点位的55.8％和35.3％);土壤对重金属元素的吸收及污染程度:Pb>Cd>Cu>Cr>zn。潜在生态危害综合指数为253.0,主要污染为Cd,达到很强的生态危害,其次是Pb、Cu、Cr和Zn,均为轻微生态危害;潜在生态危害地带自公路起向其两侧扩散范围约为150 m。[结论]公路旁土壤中重金属以Cd、Pb污染为主,属于中等生态危害,污染物主要来源于机动车辆燃料和轮胎中所含微量重金属成分。     

Heavy Metals in Livers of Waterbirds from Spain

Wetlands tend to accumulate heavy metals from local sources, such as Pb shot used for waterfowl hunting, and from regional sources, such as atmospheric deposition and riverine or marine inputs. We determined concentrations of six heavy metals (Cr, Mn, Cu, Zn, Cd, and Pb) in livers of waterbirds shot by hunters in five Spanish wetlands to study the different factors that can contribute to the accumulation of these metals (sex, age, diet, grit, and Pb shot ingestion). Differences among wetlands were observed only for Cr, Cu, and Cd. Differences among species were observed for all the metals, and Cu was notably higher in pochards (Aythya and Netta genus) than in other waterfowl. Cu, Zn, and Cd concentrations increased with age, and only Pb showed differences related to sex, with males having higher concentrations than females. Most metals other than Pb were correlated with each other. Lead was dependent on Pb shot ingestion. Grit ingestion positively correlated with concentrations of Cr and to a lesser extent with Mn, Zn, and Cd. Ingestion of grit or shot may obscure relationships between metals and diet. Herbivorous species, which had more grit in the gizzard, had higher Cr, Zn, and Cd concentrations. Granivorous birds, which have the highest rates of Pb shot ingestion, had the highest concentrations of Pb. Grit and Pb shot ingestion are both important sources of heavy metals for waterbirds. Lead was the single metal studied whose concentrations exceeded toxicity thresholds. Received: 5 March 2002/Accepted: 12 June 2002     

Availability of Heavy Metals (Cd, Pb, and Cr) in Agriculture from Commercial Fertilizers

The purpose of this study was to investigate the availability of the heavy metals cadmium (Cd), lead (Pb), and chromium (Cr) to soil and maize plants fertilized with different sources and doses of zinc (Zn) in a Rhodic Eutrudox soil. For that purpose, concentrations of Cd, Pb, and Cr were evaluated in leaf tissue and grains of maize plants and in 0–20 and 20–40 cm soil layers after fertilization with four doses of Zn from eight different sources of fertilizer. There was no accumulation of Cd, Pb, and Cr in maize grain and Cd and Cr in leaf tissue of the plants; nevertheless, there was accumulation of Pb in leaf tissue, showing its availability throughout different sources of Zn and consequent uptake by plants. Regarding the soil, it was observed that fertilizer from the different sources made Cd, Pb, and Cr available at increasing amounts proportional to increased Zn doses. Under experimental conditions, fertilization with Zn increased concentrations of heavy metals Cd, Pb and Cr in soil, further highlighting the importance of conducting more studies related to the application of mineral fertilizers for micronutrient supply and the availability of heavy metals.     

公路交通对土壤重金属污染的研究

目的评价公路交通引起的土壤中重金属污染。方法选择320国道马龙路段进行耕作土采样,用原子吸收光谱法和分光光度法分析土壤中重金属Cu、Cd、Pb、Zn、Cr、As、Ni含量,采用清洁对照区土壤剖面重金属含量作为参比值,应用地积累指数法对重金属污染叠加进行评价。结果研究区土壤中Cu、CA、Pb、Zn、Cr、As、Ni的含量显著高于对照区（P〈0．01）。Cd为中等污染～强污染,Pb为中等污染,Cr和Cu为轻污染～中等污染。污染晕带沿公路延伸方向展开,自公路起向其两侧强度运渐减弱,扩散范围约为150m。土壤对重金属元素的吸收及污染程度;Cd〉Pb〉Cr〉Cu〉As〉Zn〉Ni。结论公路旁土壤重金属污染以Cd、Pb和Cr为主,污染叠加重金属来源主要为机动车燃料、轮胎、机械中所含微量重金属成分。     

积累指数法对公路旁土壤中重金属污染的评价

目的评价公路旁土壤中重金属污染.方法以319国道龙岩市新罗区路段为例,应用积累指数法对公路环境土壤介质中重金属(Cu、Zn、Cd、Pb、As、Cr、Ni、Fe、Mn)污染叠加进行评价. 结果研究区土壤中Cd、Pb、Cr和Cu元素含量高于福建省土壤背景值,其平均含量分别是福建省土壤背景值的23.6倍、4.6倍、1.7倍和1.5倍.已形成强污染的元素为Cd,中等污染的元素为Pb,轻污染的元素为Cr.土壤对重金属元素的吸附及污染程度Cd＞Pb＞Cr＞Cu＞As＞Zn＞Ni＞Mn＞Fe.结论公路旁土壤中Cd、Pb污染严重,重金属污染物质主要来源于机动车辆燃料和轮胎中所含微量重金属成分.     

Effects of Soil Properties and Land Use Types on the Bioaccessibility of Cd,Pb, Cr,and Cu in Dongguan City,China

In order to determine the potential heavy metal contamination in soil across Dongguan City, 124 soil samples from seven land use types were collected, four heavy metals (Cd, Pb, Cr, and Cu) were analyzed. Total Cd, Cr, and Cu contents were significantly higher than the background values for Guangdong Province. Lead bioaccessibility in urban green land was lower than that in industrial and abandoned districts. The bioaccessibility of heavy metals was affected by total metal concentrations, soil properties, and land use types. The results showed that there was a negative correlation between the bioaccessibility of heavy metals (except for Cu) and their total concentrations. Soil pH and organic matter were the main factors affecting the bioaccessibility of Cd, Cr, Pb, and Cu in most land use types. Furthermore, sand, P, and clay also affected Pb, Cr, and Cu bioaccessibility. With the exception of the industrial zone periphery and urban green land, the bioaccessibility of heavy metals was mainly affected by clay.

     

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.     

Relating environmental availability to bioavailability: soil-type-dependent metal accumulation in the oligochaete Eisenia andrei

Body residues are often better estimates of the amount of a chemical at the sites of toxic action in an organism than ambient soil concentrations, because bioavailability differences among soils are explicitly taken into account in considerations of body residues. Often, however, insufficient attention is paid to the rate and extent at which tissue concentrations respond to soil concentrations and soil characteristics. In this contribution the impact of soil characteristics on the environmental bioavailability of heavy metals for the oligochaete worm Eisenia andrei is reported. Uptake of As, Cd, Cr, Cu, Ni, Pb, and Zn in 20 Dutch field soils and in OECD artificial soil was quantified as a function of time. Internal metal concentrations varied less than the corresponding external levels. Metal uptake and elimination were both metal- and species-dependent. Worms typically attained steady-state concentrations rapidly for Cr, Cu, Ni, and Zn. Internal concentrations similar to those in the cultivation medium, linearly increasing body concentrations, or steady-state internal concentrations well above those in the cultivation medium were found for As, Cd, and Pb. Multivariate expressions were derived to describe uptake rate constants, steady-state concentrations, and bioaccumulation factors as a function of soil characteristics. Soil acidity is the most important solid-phase characteristic modulating the availability of As, Cd, and Pb. Although additional semimechanistic calculations yielded evidence of pore-water-related uptake of Cd and Pb modulated by competition between H(+) and metal ions at the active sites of the membranes, the findings for Cr, Cu, Ni, and Zn point to additional influences, among which is probably regulation.     

Relating Environmental Availability to Bioavailability: Soil-Type-Dependent Metal Accumulation in the Oligochaete Eisenia andrei

Body residues are often better estimates of the amount of a chemical at the sites of toxic action in an organism than ambient soil concentrations, because bioavailability differences among soils are explicitly taken into account in considerations of body residues. Often, however, insufficient attention is paid to the rate and extent at which tissue concentrations respond to soil concentrations and soil characteristics. In this contribution the impact of soil characteristics on the environmental bioavailability of heavy metals for the oligochaete worm Eisenia andrei is reported. Uptake of As, Cd, Cr, Cu, Ni, Pb, and Zn in 20 Dutch field soils and in OECD artificial soil was quantified as a function of time. Internal metal concentrations varied less than the corresponding external levels. Metal uptake and elimination were both metal- and species-dependent. Worms typically attained steady-state concentrations rapidly for Cr, Cu, Ni, and Zn. Internal concentrations similar to those in the cultivation medium, linearly increasing body concentrations, or steady-state internal concentrations well above those in the cultivation medium were found for As, Cd, and Pb. Multivariate expressions were derived to describe uptake rate constants, steady-state concentrations, and bioaccumulation factors as a function of soil characteristics. Soil acidity is the most important solid-phase characteristic modulating the availability of As, Cd, and Pb. Although additional semimechanistic calculations yielded evidence of pore-water-related uptake of Cd and Pb modulated by competition between H⁺ and metal ions at the active sites of the membranes, the findings for Cr, Cu, Ni, and Zn point to additional influences, among which is probably regulation.     

公路旁土壤中重金属和类金属污染评价

目的 评价公路旁土训重金属和类金属污染。方法 选择３１９国道龙岩市新罗区路段进行土壤４ 采样,用原子吸收光谱法和分光光度法分析封保重金属和类金属（Ｃｄ、Ｐｂ、Ｃｕ、Ｚｎ、Ｎｉ、Ｃｒ、Ａｓ）的含量。结果 土壤综合污染指数为１．６３,ｄ、ｂ,轻度污染的元素为Ｃｕ、Ｃｒ,污染晕带自公路起向其两侧扩散范围约为２５０ｍ,土壤对重金属元素的吸附及污染程度：Ｃｄ〉Ｐｂ〉Ｃｕ〉Ｃｒ〉Ｚｎ〉Ｎｉ〉Ａｓ。结论 公路旁     

Characterization and Risk Assessment of Heavy Metals in River Sediments on the Western Bank of Taihu Lake,China

In this study, nine heavy metals (Cd, Cr, As, Hg, Pb, Cu, Ni, Be, and Sb) in the sediments of 17 typical rivers on the western bank of Taihu Lake were determined. Several statistical methods were applied to analyze the distribution, sources, pollution status, and potential ecological risk of these metals. The mean concentrations of heavy metals in sediments other than Be exceeded their local background values. Geoaccumulation index and potential ecological risk index analyses demonstrated that most sediment samples were contaminated and may pose ecological risks, especially those from the Taihu Lake estuary. In particular, Cd concentrations indicated moderate contamination and potentially serious to severe ecological risk. Principal component, cluster, and correlation analyses demonstrated that Ni, Sb, Cr, and Cu were derived from industrial sources, whereas the other metals had complex origins.

     

Influence of traffic activity on heavy metal concentrations of roadside farmland soil in mountainous areas

Emission of heavy metals from traffic activities is an important pollution source to roadside farmland ecosystems. However, little previous research has been conducted to investigate heavy metal concentrations of roadside farmland soil in mountainous areas. Owing to more complex roadside environments and more intense driving conditions on mountainous highways, heavy metal accumulation and distribution patterns in farmland soil due to traffic activity could be different from those on plain highways. In this study, design factors including altitude, roadside distance, terrain, and tree protection were considered to analyze their influences on Cu, Zn, Cd, and Pb concentrations in farmland soils along a mountain highway around Kathmandu, Nepal. On average, the concentrations of Cu, Zn, Cd, and Pb at the sampling sites are lower than the tolerable levels. Correspondingly, pollution index analysis does not show serious roadside pollution owing to traffic emissions either. However, some maximum Zn, Cd, and Pb concentrations are close to or higher than the tolerable level, indicating that although average accumulations of heavy metals pose no hazard in the region, some spots with peak concentrations may be severely polluted. The correlation analysis indicates that either Cu or Cd content is found to be significantly correlated with Zn and Pb content while there is no significant correlation between Cu and Cd. The pattern can be reasonably explained by the vehicular heavy metal emission mechanisms, which proves the heavy metals' homology of the traffic pollution source. Furthermore, the independent factors show complex interaction effects on heavy metal concentrations in the mountainous roadside soil, which indicate quite a different distribution pattern from previous studies focusing on urban roadside environments. It is found that the Pb concentration in the downgrade roadside soil is significantly lower than that in the upgrade soil while the Zn concentration in the downgrade roadside soil is marginally higher than in the upgrade soil; and the concentrations of Cu and Pb in the roadside soils with tree protection are significantly lower than those without tree protection. However, the attenuation pattern of heavy metal concentrations as a function of roadside distance within a 100 m range cannot be identified consistently.     

Trends in metals in urban and reference lake sediments across the United States, 1970 to 2001

Trends in metals concentrations in sediment cores from 35 reservoirs and lakes in urban and reference settings were analyzed to determine the effects of three decades of legislation, regulation, and changing demographics and industrial practices in the United States on concentrations of metals in the environment. Decreasing trends outnumber increasing trends for all seven metals analyzed (Cd, Cr, Cu, Pb, Hg, Ni, and Zn). The most consistent trends are for Pb and Cr: For Pb, 83% of the lakes have decreasing trends and 6% have increasing trends; for Cr, 54% of the lakes have decreasing trends and none have increasing trends. Mass accumulation rates of metals in cores, adjusted for background concentrations, decrease from the 1970s to the 1990s, with median changes ranging from -46% (Pb) to -3% (Hg and Zn). The largest decreases are from lakes in dense urban watersheds where the overall metals contamination in recently deposited sediments has decreased to one-half its 1970s median value. However, anthropogenic mass accumulation rates in dense urban lakes remain elevated over those in lakes in undeveloped watersheds, in some cases by as much as two orders of magnitude (Cr, Cu, and Zn), indicating that urban fluvial source signals can overwhelm those from regional atmospheric sources.     

Distribution Characteristic and Migration Pathways of Metals in Subsidence Zone in a Coal Mine,China

Subsidence can influence the distribution characteristics and migration pathways of metals in coal mines. In order to understand the two important and related issues of subsidence and pollution in coal mines, ten sample cores were collected in the coal mining subsidence and non-subsidence zones in Anhui province, China, and the concentration and forms of metals were analyzed. The results showed that concentrations for all metals significantly increased at the depth of 0–20 cm in these two zones. Concentrations of Cd, Cu, and Zn in the non-subsidence zone were 1.14, 1.69 and 1.48 times higher, respectively, than those in the subsidence zone, while concentrations of Cr and Pb showed no significant difference. The proportion of exchangeable and acid-extracted fractions of Cd, Cu and Zn in the non-subsidence zone were higher than those in the subsidence zone. This may be due to the different migration pathways for exchangeable and acid-extracted fractions of metals in subsidence and non-subsidence zones.     

Levels, Spatial Distribution and Possible Sources of Heavy Metals Contamination of Suburban Soils in Tianjin, China

Representative soil samples (n = 86) of suburban areas in Tianjin (Xiqing, Dongli, Jinnan, Beichen) were evaluated for heavy metals. The results showed that the average concentration of Cr, Cu, Zn, As, Cd, Pb and Hg in soil of Tianjin suburban was 101.0, 67.0, 100.6, 9.5, 0.49, 52.5 and 0.97 mg/kg, respectively. Pollution of Cr and Zn were minimal compared to the other elements while concentrations of Cd and Hg were higher than their natural background values. Spatial variations of Cd, Hg, Pb and Cu in soil were illustrated; Pollution status and comparison in the four districts were also investigated. Higher concentrations of Hg and Cd were found in soils of Beichen than others indicating that Beichen was suffering from metal contamination. Principal Component Analysis in combination with local specific environment suggested that heavy metal contamination had different origination. Wastewater and sludge irrigation, air deposition might be the most important sources. These results, especially the spatial distribution of pollutants, would be helpful to develop proper management strategies and decrease source pollution by various remediation practices in Tianjin, China.     

Heavy metal contamination of soil and vegetables in suburban areas of Varanasi, India

Heavy metal contamination of soil resulting from wastewater irrigation is a cause of serious concern due to the potential health impacts of consuming contaminated produce. In this study an assessment is made of the impact of wastewater irrigation on heavy metal contamination of Beta vulgaris (palak); this is a highly nutritious leafy vegetable that is widely cultivated and consumed in urban India, particularly by the poor. A field study was conducted at three major sites that were irrigated by either treated or untreated wastewater in the suburban areas of Varanasi, India according to normal practice. Samples of irrigation water, soil, and the edible portion of the palak (Beta vulgaris L. var All green H1) were collected monthly during the summer and winter seasons and were analyzed for Cd, Cu, Zn, Pb, Cr, Mn, and Ni. Heavy metals in irrigation water were below the internationally recommended (WHO) maximum permissible limits set for agricultural use for all heavy metals except Cd at all the sites. Similarly, the mean heavy metal concentrations in soil were below the Indian standards for all heavy metals, but the maximum value of Cd recorded during January was higher than the standard. However, in the edible portion of B. vulgaris, the Cd concentration was higher than the permissible limits of the Indian standard during summer, whereas Pb and Ni concentrations were higher in both summer and winter seasons. Results of linear regression analysis computed to assess the relationship between individual heavy metal concentration in the vegetable samples and in soil showed that Zn in soil had a positive significant relationship with vegetable contamination during winter. Concentrations of Cd, Cu, and Mn in soil and plant showed significant positive relationships only during summer. Concentration of Cr and Pb during winter season and Zn and Ni during summer season showed significant negative relationships between soil and plant contamination. The study concludes that the use of treated and untreated wastewater for irrigation has increased the contamination of Cd, Pb, and Ni in edible portion of vegetables causing potential health risk in the long term from this practice. The study also points to the fact that adherence to standards for heavy metal contamination of soil and irrigation water does not ensure safe food.     

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.     

Assessment of Heavy Metal Contamination in Roadside Surface Soil and Vegetation from the West Bank

Concentrations of heavy metals (Pb, Cd, Cu, Zn, Fe, Mn, Ni, and Cr) were investigated in roadside surface soil and the common perennial herb inula (Inula viscosa L., Compositae). Samples were collected at different distances (0–200 m) perpendicular to a main road that connects two main cities in the West Bank. Average concentrations of metals in soil samples were: Pb, 87.4; Cd, 0.27; Cu, 60.4; Zn, 82.2; Fe, 15,700; Mn, 224; Ni, 18.9; and Cr, 42.4 g · g^–1. In plant leaves, concentrations were: Pb, 7.25; Cd, 0.10; Cu, 10.6; Zn, 47.6; Fe, 730; Mn, 140; Ni, 4.87; and Cr, 7.03 g · g^–1. Roadside contamination was obvious by the significant negative correlations between concentrations of metals in soil and plant samples and distance from road edge. Only cadmium concentrations in soil and plant samples were not associated with roadside pollution. Roadside contamination in plants and soil did not extend much beyond a 20 m distance from road. I. viscosa reflected roadside contamination better than soil and their metal concentrations showed much less fluctuations than those in soil samples. Washing plant leaves decreased Pb and Fe concentrations significantly, indicating a significant aerial deposition of both. I. viscosa can be considered as a good biomonitor for roadside metal pollution.     

Heavy Metal Concentrations in Marine Fishes Collected from Fish Culture Sites in Hong Kong

The levels of six heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) in different tissues of three species of cultured marine fishes (Epinephelus areolatus, Lutjanus russelli, and Sparus sarba) collected from three fish culture sites in Hong Kong were evaluated. Metal pollution problems in the fish culture sites were serious, as reflected by the high metal concentrations recorded in sea water, sediments, and the biomonitor Perna viridis. In general, tissues of all three species contained high concentrations of Zn and Cu, but much lower concentrations of Ni, Pb, Cd, and Cr. Similar pattern of heavy metal concentrations was observed in sea water, sediment, and P. viridis. Metal concentrations in various tissues varied greatly among species and among fish culture sites. Different tissues showed different capacity for accumulating heavy metals. Gonad of all three species contained high concentrations of Zn. On the other hand, liver seemed to be the primary organ for Cu accumulation. Overall, metal concentrations in the tissues of culture marine fishes were much lower than those in P. viridis. Despite high metal levels in sea water and sediments, concentrations of Cd, Cr, and Pb in edible tissues, including muscle and skin, did not exceed permissible levels recommended by the Hong Kong Government for human consumption. Received: 3 December 1999/Accepted: 13 June 2000