Element differences and evaluation of the dietary intake from farmed oysters and mussels collected at different sites along the Croatian coast of the Adriatic Sea

Concentrations of the macroelements Ca, Mg, K and Na, microelements Cr, Cu, Fe, Mn and Zn and toxic metals As, Cd, Hg and Pb were determined in oysters and mussels collected at farming sites in the northern, central and south Adriatic Sea. Mean concentrations in oysters were (mg kg⁻¹): As 4.51, Ca 1551, Cd 1.44, Cu 53.6, Cr 0.23, Fe 45.9, Hg 0.047, K 2476, Mg 895, Mn 2.80, Na 7148, Pb 0.52, Zn 675. Mean values in mussels were (mg kg⁻¹): As 4.71, Ca 601, Cd 0.37, Cu 1.91, Cr 0.29, Fe 49.6, Hg 0.026, K 2246, Mg 1043, Mn 2.49, Na 7992, Pb 0.58, Zn 28.8. Significant differences in the concentrations of toxic metals and elements were found in oysters and mussels among farming sites. Obtained Cd, Hg and Pb concentration in oysters and mussels were lower than the limit levels set by the European Community. However, Cd concentration exceeded the limit level of 1 mg kg⁻¹ in oysters from all locations except Lim Bay. The estimated daily intakes (EDIs) indicate that oysters are a good source of Ca, Cu and Zn. The higher Cu and Zn concentrations than the toxicity reference values suggest a risk for consumers if larger quantities of oysters are consumed frequently.     

Heavy Metal Contamination in the Cultivated Oyster <Emphasis Type="Italic">Crassostrea rivularis</Emphasis> and Associated Health Risks from a Typical Mariculture Zone in the South China Sea

With the rapid development of mariculture in potentially contaminated regions in China and the world, food safety, is a growing concern. To evaluate heavy metals and their associated health risks in the cultivated oyster Crassostrea rivularis, the concentrations of heavy metals (Cd, Cr, Pb, Zn) in oysters and water/sediment were examined in a typical mariculture environment (Kaozhou Bay, South China Sea). Trends in the seasonal dynamics of heavy metals in oysters revealed a potential synergistic effects among the concentrations of Cd, Cr, and Zn; trends associated with Pb were less clear, although the ability of oysters to bioaccumulate and depurate Pb was excellent. Bioconcentration factors (BCF) indicated that C. rivularis has a strong ability to accumulate heavy metals, and the BCF was the highest for Zn (2.32?×?10⁵), followed by Cd (6.84?×?10⁴), Pb (2.77?×?10⁴) and Cr (1.23?×?10³) through the four seasons. Results showed that Cd concentrations in oysters could pose a risk to human health (HQ?>?1). This study, therefore, suggests that there are potential human health risks due to heavy metal exposure through the consumption of C. rivularis from mariculture zones in South China Sea.     

Geo-Accumulation Indices of Heavy Metals in Soil and Groundwater of Kanpur,India Under Long Term Irrigation of Tannery Effluent

Soil and groundwater from long-term (>50 years) tannery effluent irrigated areas of Kanpur were analyzed and significant buildup of heavy metals such as Cr, Ni, Cd, Pb, Zn, and As in the range of 252–972, 23–30, 2.3–14.1, 23.7–58.8, 138–338 and 6.8–11 mg kg^?1, respectively in soil was found. Few groundwater samples in the effluent irrigated areas also exhibited high Cr concentration above the permissible limit of United States Environmental Protection Agency. The tannery effluents contained 1.53–57.3 ppm Cr, 0–0.12 ppm Ni, 0–0.02 ppm Cd, 0–0.07 ppm Pb, 0–0.48 ppm Zn and 0–0.03 ppm As. The Geo-accumulation index (I_geo) revealed that soil samples were unpolluted to moderately polluted with Cu, Ni, Zn, Pb and As; moderately polluted in case of Cd; and heavily to extremely polluted by Cr.     

Filterable Plasma Concentration,Glomerular Filtration,Tubular Balance,and Renal Clearance of Heavy Metals and Organic Substances in Metal Workers

To estimate “filterable” plasma concentration (FPx), glomerular filtration, tubular balance, and renal clearance of heavy metals and organic substances, the authors examined the regressions of the 24-hr urinary excretion on glomerular filtration rate [GFR, 24-hr endogenous creatinine (Cn) clearance] in 19 gun-metal foundry workers with blood lead (Pb) concentrations of 25–59 μg/dl. It was estimated that the proportion of FPx to total plasma concentration was on average 15,7,3,0.6,0.06, and 0.008% for Pb, cadmium (Cd), manganese (Mn), zinc (Zn), chromium (Cr), and copper (Cu), respectively. The estimated FPx value was 2.8 × 10², 4,0.08, and 2.8 × 10⁴ μg/dl. for hippuric acid (HA), delta-aminolevulinic acid (ALA), coproporphyrin (CP), and total urinary solutes (TUS), respectively. The estimated glomerular filtration was significantly greater than the zero level for all substances but inorganic mercury (Hg). Similarly, the estimated net tubular secretion was significantly greater than the zero level for Cr, Cu, and TUS; the net tubular reabsorption was significantly greater than the zero level for Pb, ALA, and CP. The renal clearance of “filterable” plasma substance was significantly greater than GFR for Cr, Cu, and TUS and was significantly smaller for Pb, ALA, and CP. Thus the renal excretory mechanisms of substances were classified into four major categories: (1) glomerular filtration for Cd, Mn, Zn, HA, and Cn; (2) glomerular filtration and net tubular secretion for Cr, Cu, and TUS; (3) glomerular filtration and net tubular reabsorption for Pb, ALA, and CP; and (4) no glomerular filtration, i.e., suspected tubular secretion, for Hg.     

Determination and chemometric evaluation of the mineral profile of maize flours

Maize flour is a food rich in nutrients important for the proper functioning of the human body. Nevertheless, for the determination of metals in maize flour there are few studies, which raise concern about quality and its mineral composition for consumption. In this work, it was evaluated the concentration of essential (Ca, Cu, Fe, Mn, Mg, Cr and Zn) and non-essential (Cd and Cr) metals in yellow and white maize flour samples produced in Paraná State - Brazil. For this purpose, it was performed a sample treatment employing wet digestion in a digester block and determination of metals by atomic absorption spectrometry (AAS). The highest concentrations found in the flour were Ca (55.4 mg kg⁻¹) and Mg (86.9 mg kg⁻¹) and the lowest concentrations were Cr (0.11 mg kg⁻¹) and Cd (0.01 mg kg⁻¹). In yellow and white maize flour the highest concentration was for Mg, 81.5 mg kg⁻¹and 98.4 mg kg⁻¹, respectively. Principal component analysis (PCA) showed that some samples had a similar mineral profile, such as the relationship with the place of origin of the cereal.     

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     

Plankton as an Indicator of Heavy Metal Pollution in a Freshwater Reservoir of Madhya Pradesh, India

Halali Reservoir is an important freshwater body of Madhya Pradesh. The water of the reservoir is used for drinking, irrigation and aquaculture practices. It receives untreated sewage, wastes from small scale industries and agricultural runoff from the catchment area. Various heavy metal (Cd, Cr, Cu, Ni, Pb and Zn) levels were measured in plankton of Halali Reservoir during 2006–2007 by inductively coupled plasma—optical emission spectrometry. Mean concentration ranges for Cd, Cr, Cu, Ni, Pb and Zn were 0.0018–0.0037, 0.0038–0.2257, 0.0013–0.0228, 0.0011–0.0086, 0.0133–0.0494 and 0.0130–0.1168 μg g^?1, respectively. Overall, mean Cr concentrations in the plankton were generally the highest of the six metals at four of the five study sites. Metal concentrations at these four sites generally followed the order: Cr > Zn > Pb > Cu > Ni > Cd. Mean concentrations of all metals at a fifth site were consistently lower than at the other sites. The high levels of Cr in the plankton are in agreement with high Cr levels that have been reported in fish from this reservoir, indicating that plankton may serve as a useful indicator of metal pollution in fish.     

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.     

Spatial and Seasonal Distribution of Trace Metal Concentrations in Mussel (Mytilus galloprovincialis) and Sediment of Bosphorus and Golden Horn

The Golden Horn Estuary and Bosphorus Strait are two major marine environments of metropolitan Istanbul which have been exposed to intensive industrial discharges for more than 50 years. In the present study, concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and zinc (Zn) were measured in mussel tissue and sediment samples by using inductively coupled plasma-atomic emission spectroscopy to assess the current status of metal pollution in the Golden Horn and Bosphorus Strait. Ranges of Cd, Cr, Cu, Pb and Zn concentrations in soft parts of the mussels were BDL-2.59; BDL-7.35; 3.96–20.90; BDL-10.0; and 124.8–293.2 μg g^?1 dry weight (dw), respectively, while the ranges of Cd, Cr, Cu, Pb and Zn in <63 μm sediment fractions were BDL, 19.5–300.3, 16.9–724.7, 10.5–260.9, and 39.3–793.1 μg g^?1 dw, respectively. Ranges of Cd, Cr, Cu, Pb and Zn in >63 μm sediment fractions were BDL, 4.73–52.81, 3.45–481.87, 3.13–174.67 and 10.7–241.2 μg g^?1 dw, respectively. Trace metal concentrations found in sediment of the Golden Horn were 5–10 times higher than average literature values obtained in Mediterranean marine environment, whereas those of the Bosphorus Strait were consistent with or slightly higher than average literature values.     

Spatial Distribution and Contamination Assessment of Heavy Metals in Urban Topsoils from Las Tunas City, Cuba

Concentrations of Cr, Co, Ni, Cu, Zn, Pb and Fe in the topsoils (0–10 cm) from Las Tunas city were measured by X-ray fluorescence analysis. The mean Cr, Co, Ni, Cu, Zn and Pb contents in the urban topsoil samples (97 ± 30, 14 ± 2, 35 ± 36, 94 ± 26, 199 ± 87 and 42 ± 29 mg kg^?1 dry weight, respectively) were compared with mean concentrations for other cities around the world with similar population. Cr content in school grounds, parks and residential areas exceed in 20 % the average Cr background level. Highest content for Ni was determined in residential areas, for Zn in market gardens soils and as for Pb, the highest topsoil-background content ratios were observed for market gardens (2.7) and residential areas (2.3). Spatial distribution maps indicated the same behaviour for Cr–Co–Ni and Pb–Zn, respectively, whereas the spatial distribution of Cu differs from other heavy metals. On the other hand, the metal-to-iron normalisation, using (10–20 cm) bottom soil contents as background, showed that topsoils in Las Tunas city are severely enriched with lead and not enriched with the rest of the determined metals. The average values of integrated pollution index (IPI) indicated that soils are moderately contaminated by heavy metals (1.17 ≤ IPI_ave ≤ 1.39), but enrichment index values shows that metal concentrations on the studied locations are not above the permissible levels for urban agriculture.     

Composition of heavy metals in indoor dust and their possible exposure: a case study of preschool children in Malaysia

The aim of this study is to determine the levels of selected heavy metals (Pb, Zn, Cd, Fe and Cr) at ten preschools in Selangor, Malaysia. Dust samples from the interior of classrooms and surface soils were collected using soft paint brushes while Kimwipes were used to collect samples of dust from interior walls and children’s palms. Heavy metals in the dust samples were determined using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of the selected heavy metals in the indoor dust were dominated by Fe with a concentration of 4,801?±?1,873 μgg^?1 followed by Pb?>?Zn?>?Cr and Cd with concentration of 253.5?±?83.2, 144.9?±?73.4, 11.9?±?6.8 and 0.23?±?0.10 μgg^?1, respectively. Fe also had the highest concentration of all the heavy metals investigated in the samples taken of soil dust (8,225?±?6,800 μgg^?1), the interior walls (1,865?±?756 μgm^?2) and children’s palms (3,882?±?3,401 μgm^?2). Using enrichment factor (EF) analyses, Pb, Zn and Cd in the indoor dust were found contributed by anthropogenic factors while the same was true for Zn, Cd and Cr in the indoor wall and children’s palm samples.     

Heavy Metal Contamination and Ecological Risk Assessment of Swine Manure Irrigated Vegetable Soils in Jiangxi Province,China

Heavy metal are often added to animal fodder and accumulate in the soils with swine manure. In this study, heavy metal (Cu, Pb, Cd, Zn, As and Cr) concentrations were determined in agricultural soils irrigated with swine manure in Jiangxi Province, China. Results showed that the average concentrations of Cu, Zn, As and Cr (32.8, 93.7, 21.3 and 75.8 mg/kg, respectively) were higher than the background values, while Pb and Cd (15.2 and 0.090 mg/kg, respectively) were lower than the background values. Contamination factors \(\left( {C_{f}^{i}} \right)\) indicated that they were generally moderate for Cu, Zn, As and Cr and generally low for Pb and Cd. The contamination degree (C _d ) was calculated to be 7.5–10.0 indicating a moderate degree of contamination. The geoaccumulation index (I_geo) indicated that the soils were unpolluted with Zn, Cd and Pb, while unpolluted to moderately pollute with Cr, Cu and As. The single ecological risk factor \(\left( {E_{r}^{i}} \right)\) revealed that the six heavy metals all belonged to low ecological risk. The ecological risk indices suggested that all the sampling sites were at low risk level.     

Direct atomic absorption spectrometry determination of arsenic,cadmium, copper,manganese, lead and zinc in vegetable oil and fat samples with graphite filter furnace atomizer

The article presents the results of optimization of operation parameters, investigation of analytical characteristics and the abilities of a graphite filter-furnace (FF) atomizer for the direct electrothermal atomic absorption spectroscopy (ET AAS) determination of trace amounts of Mn, As, Pb, Cu, Cd and Zn in some vegetable oils and fats. The effect of pyrolysis and atomization temperatures of the graphite FF atomizer on atomic absorbance values of the listed elements at their evaporation from some organic solutions in the presence of a Pd-Mg chemical modifier (CM) was investigated. For the ET AAS determination of As, Pb, Cd and Zn with Pd-Mg CM, the temperature of the graphite FF atomizer for the pyrolysis step can be raised by 250–350 °C. This mode allows to eliminate the background absorption, to increase the sensitivity of the elements to be analyzed and to enhance the total content of vegetable oils or fats in organic solutions up to 0.5 g mL⁻¹. The obtained limits of quantification for Mn, As, Pb, Cu, Cd and Zn were 0.002, 0.004, 0.004, 0.002, 0.0008, 0.0004 mg kg⁻¹, respectively. The relative standard deviation (RSD) varied between ∼3 and 8% and the time of one element determination did not exceed ∼3–5 min. The reliability of the proposed method was checked using the reference method. A paired Student's t-test showed no significant difference between the results obtained by both methods on a 95% confidence level.     

Assessment of trace metals in foodstuffs grown around the vicinity of industries in Bangladesh

In the present study, we investigated the levels of chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), cadmium (Cd) and lead (Pb) in eight groups of foods, namely, cereals, pulses, vegetables, fruit, fish, meat, eggs and milk. The range of Cr, Ni, Cu, As, Cd and Pb in the foodstuffs was 0.18–4.8, 0.008–10, 0.47–22, 0.003–0.98, 0.0003–0.85 and 0.005–3.7 mg/kg fw, respectively. The daily intakes (EDIs) of Cr, Ni, As, Cd and Pb were higher than the maximum tolerable daily intake (MTDI), indicating their potential sources from dietary intake. The combined metal hazard quotients (∑HQs) from rice, fruit, vegetables and fish were higher than 1, meaning that metals may pose a considerable risk to local inhabitants due to consumption of these four food items. From the human health point of view, this study showed that the studied foods were not safe for the local inhabitants, and potential risk cannot be neglected for regular or excessive consumers.     

Occurrence of trace metals in fish from South Italy: Assessment risk to consumer’s health

The concentrations of nine trace elements (Hg, Cd, Pb, V, Ni, Co, Cr, Cu and Zn) were determined in sixteen fish species collected in commercial centers of South Italy. Additionally, the assessment of risk indices (Hazard Quotient, Hazard Index, Incremental Lifetime Cancer Risk) through the consumption of various fish species were estimated in different age groups. The concentrations fell under the maximum permissible levels (MPLs) for human consumption recommended by European Union, with an only exception regarding Cd, which exceeded the tolerable value in Atlantic bluefin tuna samples. The estimated weekly intakes of metals, all below Provisional Tolerable Weekly Intakes (PTWIs), were in the following decreasing order: children > teenagers > adults > elders. The estimated hazard quotient (HQ) of Hg being above or close to 1 indicated a high probability of experiencing non-carcinogenic health risks, while the noncarcinogenic threats associated with exposure to other metals were insignificant (< 1) for all age groups. The cumulative cancer risk (ΣILCR) in children (1.86 × 10⁻³) and teenagers (1.10 × 10⁻³) exceed the cancer benchmark by a greater margin than adults (7.53 × 10^-4) and elders (6.43 × 10^-4). These results impose a systematic monitoring of fish, especially of large predatory fish, so to ensure the continuing safety of this food safeguarding human health.     

Evaluation of Sediment Contamination by Heavy Metals, Organochlorinated Pesticides, and Polycyclic Aromatic Hydrocarbons in the Berre Coastal Lagoon (Southeast France)

During the last decades, the Berre lagoon, located in southeastern France, has been deeply affected by strong contaminant inputs. Surveys of surface sediment contamination have been sparsely performed since 1964 with data often disconnected with regard to time and space. To contribute to filling this gap, this study examined the pollution status of the lagoon during a 2012 sampling. Concentrations of heavy metals (HMs) (cadmium [Cd], chromium [Cr], copper [Cu], lead [Pb], and zinc [Zn]), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons were examined. The available seawater metal fraction was also investigated. Water from the Vaine basin (VB; stations 1 through 6) exhibited the lowest oxygen concentration (mean O₂ % saturation 38.9 %). HM loads were in the order of Zn > Cr > Pb > Cu > Cd with overall concentration ranges of 0.20–1.40 mg kg^?1 for Cd, 17.1–119 mg kg^?1 for Cr, 7.0–60.7 g^?1 for Cu, 12.0–104 mg kg^?1 for Pb, and 56.5–215 mg kg^?1 for Zn. Although HMs accumulated at levels largely exceeding their relative natural background level of 11-fold for Pb and 80-fold for Zn, their mean concentrations decreased largely to below the acceptable legal limits. HM loads were 20 to threefold the relative corresponding value of the threshold effect level benchmark of potential biological risk. Metals were only scantly released by sediments with mean percentage release of 0.99 % for Cd and 40.2 % for Cr with a peak for this latter element of 99 % in the VB sector. In the case of OCPs, sediments appeared to be significantly polluted, especially in the VB area, with a mean lindane concentration of 0.05 mg kg^?1, which is ≤fivefold the legal threshold. Among PAHs, benzo[a]pyrene exceeded the permitted limit of 0.1 mg kg^?1 mainly in the VB sector.     

Variations of heavy metals and arsenic in fish and other organisms from the Calcasieu River and Lake,Louisiana

The edible parts of several species of fish and other marine organisms inhabiting the Calcasieu River/Lake, Louisiana were analyzed for Cd, Cr, Cu, Pb, Hg, Ag, Zn, and As. Concentrations of all metals measured in both intra and interspecies showed no significant variation with sample location. Differences in elemental concentrations were related to organism mobility and not to site-specific variations in metal loadings. Different species of finfish contained only trace amounts of Cd (0.02-0.08), Ag (<0.01–0.3), Pb (<0.2–0.5), and As (<0.1–0.3) mg kg^–1. Concentrations of Cu and Cr were highly variable, in contrast to Zn, which was present in relatively constant amounts across all species (28 ± 7 mg kg^–1). Sessile organisms such as oysters had the highest concentrations of heavy metals, including Cd. Periphyton and Zooplankton were the only groups that showed differences in metal concentrations with sampling location.     

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。     

Impact of Long-Term Application of Sewage on Soil and Crop Quality in Vertisols of Central India

Shortfall of rain and the decreased groundwater level force farmers to use poor quality water for crop production in developing countries. In this study, the quality of agricultural produce and soil health affected by sewage water (Patranala) irrigation was evaluated. Sewage sediment, soil and crop samples were analyzed for physico-chemical properties. Sewage water found to contain trace concentration of heavy metals. However, long-term application of this water for crop production could build up a significant amount of trace metals in both soil and sediments. The DTPA extractable heavy metals ranged Cu 2.7–7.59, Cd 0.04–0.06, Pb 1.29–2.05, Cr 0.01–0.04, Ni 0.24–1.03 and Zn 0.63–2.59 mg kg^?1 soil. The heavy metal risk assessment (hazard quotient, HQ) was calculated and found that HQ for these metals in the crops under study was in safe limits. From the study, it is concluded that growing vegetables using sewage water of Patranala is safe, but periodic monitoring to be carried out to avoid food chain contamination.     

Health risks in rural populations due to heavy metals found in agricultural soils irrigated with wastewater in the Alto Balsas sub-basin in Tlaxcala and Puebla,Mexico

The aim of this study was to determine the hazard ratio (HQ), the risk index (HI), and the cancer risk index (CRI) for populations of adults and children exposed to ingestion, dermal contact and inhalation of heavy metals in agricultural soil. For these, the contents of Cd, Pb, Ni, Cu, Co, Cr, Zn, and the metalloid As were determined in soils of four zones of the sub-basin of Alto Balsas, during two different periods of the year. The average content of metals in the soil was 1.24, 14.77, 14.80, 13.06, 5.50, 17.65, 22.89, and 5.32 mg kg^?1 for Cd, Pb, Ni, Cu, Co, Cr, Zn, and As, respectively. The highest risk in terms of HQ and HI was for adults, especially for men who are affected through the skin, with Cd and Cr being the most dangerous. CRI values were within the allowable range, without posing problems for adult and child populations.