Health risk assessment of heavy metals for edible parts of vegetables grown in sewage-irrigated soils in suburbs of Baoding City,China

With the long-term application of wastewater to vegetable production fields, there is concern about potential health risks of heavy metals contaminating the edible parts of vegetables grown in contaminated soils in the suburban areas of Baoding City, China. The average concentration of elemental Zn in sewage-irrigated soil was the highest (153.77 mg kg⁻¹), followed by Pb (38.35 mg kg⁻¹), Cu (35.06 mg kg⁻¹), Ni (29.81 mg kg⁻¹), and Cd (0.22 mg kg⁻¹) which were significantly higher (P < 0.05) than those in the reference soil. The results showed that long-term sewage irrigation had led to a growing accumulation of heavy metals in the soils, especially for Cd, Zn, and Pb. Furthermore, the concentrations of elemental Cd, Zn, and Ni in vegetables (e.g., Beassica pekinensis L., Allium fistulosum L., Spinacia oleracea L.) collected from the wastewater-irrigated soils exceeded the maximum permissible limits, and this also increased the daily intake of metals by food. However, compared with the health risk index of <1 for heavy metals, the ingestion of vegetables from the soils irrigated with sewage effluent posed a low health risk. Nevertheless, heavy metal concentrations should be periodically monitored in vegetables grown in these soils together with the implementation effective remediation technologies to minimize possible impacts on human health.     

Fertigation effect of distillery effluent on agronomical practices of Trigonella foenum-graecum L. (Fenugreek)

The fertigation effect of distillery effluents concentrations such as 5%, 10%, 25%, 50%, 75% and 100% were studied on Trigonella foenu-graecu (Pusa early bunching) along with control (bore well water). On irrigation of soil with different effluents up to 90 days of harvesting, it was observed that there was a significant effect on moisture content (P < 0.001), EC, pH, Cl⁻, total organic carbon (TOC), HCO₃^-_{3}^{-}, CO₃^-2_{3}^{-2}, Na⁺, K⁺, Ca^2 +, Mg^2 +, Fe^2 +, TKN, NO₃^2-_{3}^{2-}, PO₄^3-_{4}^{3-}, and SO₄^2-_{4}^{2-} (P < 0.0001) and insignificant effect on WHC and bulk density (P > 0.05).There was no significant change in the soil texture of the soil. Among various concentrations of effluent irrigation, the irrigation with 100% effluent concentration decreased pH (16.66%) and increased moisture content (30.82%), EC(84.13%), Cl⁻ (292.37%), TOC (4311.61%), HCO₃^-_{3}^{-} (27.76%), CO₃^-2_{3}^{-2} (32.63%), Na⁺ (273%), K⁺ (31.59%), Ca^2 + (729.76%), Mg^2 + (740.47%), TKN (1723.32%), NO₃^2-_{3}^{2-} (98.02%), PO₄^3-_{4}^{3-} (337.79%), and SO₄^2-_{4}^{2-} (77.78%), Fe^2 + (359.91%), Zn (980.48%), Cu (451.51%), Cd (3033.33%), Pb (2350.00%), and Cr (2375.00%) in the soil. The agronomical parameters such as shoot length, root length, number of leaves, flowers, pods, dry weight, chlorophyll content, LAI, crop yield, and HI of T. foenum-graecum were recorded to be in increasing order at low concentration of the effluent, i.e., from 5% to 50% and in decreasing order at higher effluent concentration, i.e., from 75% to 100% as compared to control. The enrichment factor of various heavy metals was ordered for soil Cd>Cr> Pb>Zn>Cu>Fe and for T. foenum-graecum plants Pb>Cr>Cd>Cu>Zn>Fe after irrigation with distillery effluent.     

Evaluation of groundwater suitability for domestic,irrigational, and industrial purposes: a case study from Thirumanimuttar river basin,Tamilnadu, India

The Thirumanimuttar sub-basin forms an important groundwater province in south India, facing serious deficiency in both quality and quantity of groundwater due to increased demand associated with rapid population explosion, agricultural growth and industrial activities. A total of 194 groundwater samples were collected and 15 water quality parameters were analyzed using standard procedures. Na⁺, Cl⁻, Ca^2 +, HCO₃^-_{3}^{-}, Mg^2 + and SO₄^2-_{4}^{2-} concentration ions are more dominant in both seasons. The total dissolved solids and electrical conductivity was observed good correlation with Na⁺, Cl⁻, HCO₃^-_{3}^{-}, Ca^2 +, Mg^2 +, Cl⁻, PO₄^3-_{4}^{3-} and NO₃^- _{3}^{- } ions indicating dominance of plagioclase feldspar weathering, anthropogenic input and over drafting of groundwater irrespective of seasons. The Hill–Piper diagram indicates alkaline earths exceed the alkalis, an increase of weak acids was noted during both the seasons. For assessing the groundwater for irrigation suitability parameters like total hardness, sodium adsorption ratio, residual sodium carbonate (RSC), permeability index, and sodium percentage are also calculated. Permanent hardness was noted in higher during both the seasons due to discharge of untreated effluents and ion exchange process. The RSC indicates 56% of the samples are not suitable for irrigation purposes in both seasons, if continuously used will affect the crop yield. From the results, nearly 72% of the samples are not suitable for irrigation.     

Pasture composition in a trace element-contaminated area: the particular case of Fe and Cd for grazing horses

Pasture selection by livestock is an essential topic for rangeland management, especially in trace element-contaminated soils. We have studied the composition (nutrients and trace elements) of a grass-based diet from soils affected by a mine spill at different growth stages (October 2008 to May 2009). A diet based on other plants (mainly Compositae species) was also studied (May 2009) for comparison. Faeces and mane hair of horses feeding on these pastures were also analysed. Micronutrient (Cu, Fe, Mn and Zn) and potentially toxic trace element (As, Cd, Pb, Tl) concentrations were below the maximum tolerable levels (MTL) for horses, except for Fe (at early growth of pastures) and Cd (in the diet based on ‘other’ plants). Values of potential ingestion of Fe by horses were higher than 10 mg kg body weight^− 1 day^− 1. Cadmium concentrations in some pasture samples (those composed of Compositae species) were higher than 3 mg kg^− 1. Potential toxicity of such Cd levels in pastures is uncertain, since a high disparity of criteria about MTL by cattle exists (between 0.5 and 10 mg kg^− 1 diet). Nutrient concentrations were adequate for horses, which could counteract possible harmful effects derived from trace element ingestion. The analyses of excreta and mane hair point to the low risk of toxicity derived from the consumption of these contaminated pastures. However, the ingestion of regenerating pastures (autumnal samples) should be avoided due to the greater risk of ingestion of contaminated soil attached to the plant material. Management of these pastures by grazing requires periodic monitoring. Special attention should be given to Fe and particularly Cd (non-essential element) which accumulates in animal organs, where it could provoke uncertain long-term effects.     

Fractionation and mobility of cadmium and zinc in urban vegetable gardens of Kano, Northern Nigeria

Metal fractionation provides information on mobility and stability of various metal species which can be used to evaluate the movement of such metals in soils. The effect of wastewater irrigation on the fractions, spatial distribution, and mobility of cadmium (Cd) and zinc (Zn) was investigated in five urban gardens in Kano, Nigeria. Concentration of total Zn in the surface soils (0–20 cm) ranged from 121 to 207 mg kg^− 1 while Cd concentration was 0.3–2.0 mg kg^− 1. Speciation of both heavy metals into seven operationally defined fractions indicated that the most reactive forms extracted with ammonium nitrate and ammonium acetate, also considered as the bioavailable fractions, accounted for 29–42% of total Cd and 22–54% of total Zn, respectively. The weakly bound fractions of Cd and Zn reached up to 50% of the total Cd and Zn concentrations in the soils. Such high proportions of labile Cd and Zn fractions are indicative of anthropogenic origins, arising from the application of wastewater for irrigation and municipal biosolids for soil fertility improvement. Thus, given the predominance of sandy soil textures, high concentrations of labile Cd and Zn in these garden soils represent a potential hazard for the redistribution and translocation of these metals into the food chain and aquifer.     

Major ion chemistry of shallow groundwater of a fast growing city of Central India

Nagpur City located in semiarid area of central India is a fast-growing industrial centre. In recent years, rapid development has created an increased demand for drinking water, which is increasingly being fulfilled by groundwater abstraction. The present study was undertaken to assess major ion chemistry of shallow groundwater to understand geochemical evolution of groundwater and water quality for promoting sustainable development and effective management of groundwater resources. A total of 47 water samples were collected from shallow aquifer of selected parts of the city and the water chemistry of various ions viz. Ca^2 +, Mg^2 +, Na⁺, K⁺, CO₃  ^2-_{3}^{\ \, 2-}, HCO₃  ^-_{3}^{\ \, -}, Cl⁻, SO₄  ^2-_{4}^{\ \,2-} and NO₃  ^-_{3}^{\ \,-} are carried out. The chemical relationships in Piper diagram identify Ca–HCO₃–Cl and mixed Ca–Na–HCO₃–Cl as most prevalent water types. Alkaline earth exceeds alkalis and weak acids exceed strong acids. Ionic ratios and Gibb’s diagram suggest that silicate rock weathering and anthropogenic activities are the main processes that determine the ionic composition in the study area. The nitrate appeared as a major problem of safe drinking water in this region. We recorded highest nitrate concentration, i.e., 411 mg/l in one of the dug well. A comparison of groundwater quality in relation to drinking water quality standards revealed that about half of the shallow aquifer samples are not suitable for drinking.     

Bioaccumulation of trace elements in different tissues of three commonly available fish species regarding their gender,gonadosomatic index,and condition factor in a wetland ecosystem

In the present research, accumulation of Cd, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn were determined in sediments and fillet, liver, kidney, gonads, and gills of three commonly fish species in the largest wetland ecosystem that is located in southwest of Iran; Shadegan wetland. Shadegan is one of the most important wetland that posses various fauna and flora but suffers inputs from agricultural and industrial activities. So, sediment samples and fish species including Barbus grypus, Barbus sharpeyi, and Cyprinus carpio were collected during winter 2009. Results showed that mean concentrations of trace elements (except Ni and Co) were high in liver and gills of B. grypus. Also trace elements had the most accumulation in liver of B. sharpeyi except for Cd (0.26 mg kg^− 1 d.w.) and Mn (13.45 mg kg^− 1 d.w.) that were high in gills. Beside, kidney is determined as target tissue for Ni and V in B. grypus and for Pb in C. carpio, due to their high concentration. Zn levels in all tissues of C. carpio showed the highest concentrations in comparison to other fish species. Generally, accumulations of most of the studied elements in B. grypus and B. sharpeyi were higher in females than in males, while in fillet and gonads of C. carpio, this trend was inverted. Bioaccumulation factors (BAFs) were determined for different tissues of fish species with respect to elemental concentrations in sediment. BAFs results indicated that Zn, Pb, and Cu have higher BAF than other elements. Also this investigation demonstrated that trace elements have different affinities with condition factor of studied fish species. Gonadosomatic index (GSI) and Pb showed positive correlation together in both B. sharpeyi and B. grypus, respectively, in females and males. Moreover, females of C. carpio showed significantly positive relation of GSI and all studied elements.     

Risk assessment due to intake of heavy metals through the ingestion of groundwater around two proposed uranium mining areas in Jharkhand,India

Heavy metal pollution of water resources can be apprehended in East Singhbhum region which is a highly mineralised zone with extensive mining of copper, uranium and other minerals. Ten groundwater samples were collected from each site and the heavy metal analysis was done by atomic absorption spectrophotometer. Analysis of the results of the study reveals that the concentration of iron, manganese, zinc, lead, copper and nickel in groundwater of Bagjata mining area ranged 0.06–5.3 mg l^− 1, 0.01–1.3 mg l^− 1, 0.02–8.2 mg l^− 1, 1.4–28.4 μg l^− 1, 0.78–20.0 μg l^− 1 and 1.05–20.1 μg l^− 1, respectively. In case of Banduhurang mining area, the range was 0.04–2.93 mg l^− 1, 0.02–1.1 mg l^− 1, 0.01–4.68 mg l^− 1, 1.04–33.21 μg l^− 1, 1.24–18.7 μg l^− 1 and 1.06–14.58 μg l^− 1, respectively. The heavy metals were found to be below the drinking water standards (IS:10500 1993) except iron (0.3 mg l^− 1) and manganese (0.1 mg l^− 1). The hazard quotients of the heavy metals for drinking water were below 1 posing no threat due to intake of water to the people for both the areas.     

Characterizing hydrochemical properties of springs in Taiwan based on their geological origins

This study was performed to characterize hydrochemical properties of springs based on their geological origins in Taiwan. Stepwise discriminant analysis (DA) was used to establish a linear classification model of springs using hydrochemical parameters. Two hydrochemical datasets—ion concentrations and relative proportions of equivalents per liter of major ions—were included to perform prediction of the geological origins of springs. Analyzed results reveal that DA using relative proportions of equivalents per liter of major ions yields a 95.6% right assignation, which is superior to DA using ion concentrations. This result indicates that relative proportions of equivalents of major hydrochemical parameters in spring water are more highly associated with the geological origins than ion concentrations do. Low percentages of Na⁺ equivalents are common properties of springs emerging from acid-sulfate and neutral-sulfate igneous rock. Springs emerging from metamorphic rock show low percentages of Cl⁻ equivalents and high percentages of HCO₃^-_{3}^{-} equivalents, and springs emerging from sedimentary rock exhibit high Cl⁻/SO₄^2-_{4}^{2-} ratios.     

Assessment of the sources of suspended particulate matter aerosol using US EPA PMF 3.0

The main purpose of this paper was to carry out a source apportionment of suspended particulate matter (SPM) samples using positive matrix factorization procedure. The central and local Government of Japan introduced strict emission regulations in 2002/10 and 2003/10, respectively, in curbing SPM pollution from major metropolitans. This paper also highlighted the impact of the measures taken by the central and local Government of Japan on the reduction of SPM and the contributions of sources. SPM samples were collected for 6 years starting from 1999 to 2005 at two sites, i.e., site A (urban) and site B (suburban) of Yokohama, Japan. Microwave digestion and inductively coupled plasma-mass spectroscopy (ICP-MS) were employed to measure Mg, Al, Ca, V, Cr, Mn, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and Bi, while water soluble ions (Na⁺, NH₄  ⁺_{4}^{\ \,+}, K⁺, Ca^2 +, Mg^2 +, Cl⁻, NO₃  ^-_{3}^{\ \,-} and SO₄  ^2-)_{4}^{\ \,2-}) as well as carbonaceous mass (EC and OC) were analyzed using ion chromatograph and CHN analyzer, respectively. The sources identified at two sites were automobile, soil dust, marine aerosol, mixed sources, and secondarily formed aerosol. Also, source quantification was performed. Automobile and soil dust were striking contributors at site A. Automobile and soil dust of SPM aerosol might be produced from local origin at current study areas. Besides, Asian dust had an impact on high concentrations of SPM aerosol in some certain period of the year due to the outflows of East Asian emission. In contrast, secondary aerosol in the form of sulfate and ammonium as well as mixed sources (coal, long-transported Cs, and other unknown sources) were remarkable at site B. Stationary/industrial combustion has apparently more impact on the release of SPM components at site B than A. Automobile regulations in 2002 and 2003, respectively, resulted in reduction of SPM by 28% for site A and 16% for site B. There was also net reduction of automobile contribution at both sites due to the above measures being implemented.     

Geochemical position of Pb,Zn and Cd in soils near the Olkusz mine/smelter,South Poland: effects of land use,type of contamination and distance from pollution source

The soils adjacent to an area of historical mining, ore processing and smelting activities reflects the historical background and a mixing of recent contamination sources. The main anthropogenic sources of metals can be connected with historical and recent mine wastes, direct atmospheric deposition from mining and smelting processes and dust particles originating from open tailings ponds. Contaminated agriculture and forest soil samples with mining and smelting related pollutants were collected at different distances from the source of emission in the Pb–Zn–Ag mining area near Olkusz, Upper Silesia to (a) compare the chemical speciation of metals in agriculture and forest soils situated at the same distance from the point source of pollution (paired sampling design), (b) to evaluate the relationship between the distance from the polluter and the retention of the metals in the soil, (c) to describe mineralogy transformation of anthropogenic soil particles in the soils, and (d) to assess the effect of deposited fly ash vs. dumped mining/smelting waste on the mobility and bioavailability of metals in the soil. Forest soils are much more affected with smelting processes than agriculture soils. However, agriculture soils suffer from the downward metal migration more than the forest soils. The maximum concentrations of Pb, Zn, and Cd were detected in a forest soil profile near the smelter and reached about 25 g kg^− 1, 20 g kg^− 1 and 200 mg kg^− 1 for Pb, Zn and Cd, respectively. The metal pollutants from smelting processes are less stable under slightly alkaline soil pH then acidic due to the metal carbonates precipitation. Metal mobility ranges in the studied forest soils are as follows: Pb > Zn ≈ Cd for relatively circum-neutral soil pH (near the smelter), Cd > Zn > Pb for acidic soils (further from the smelter). Under relatively comparable pH conditions, the main soil properties influencing metal migration are total organic carbon and cation exchange capacity. The mobilization of Pb, Zn and Cd in soils depends on the persistence of the metal-containing particles in the atmosphere; the longer the time, the more abundant the stable forms. The dumped mining/smelting waste is less risk of easily mobilizable metal forms, however, downward metal migration especially due to the periodical leaching of the waste was observed.     

Comparison of some quality properties of soils around land-mined areas and adjacent agricultural fields

When agricultural lands are no longer used for agriculture and allowed to recover its natural vegetation, soil organic carbon can accumulate in the soil. Measurements of soil organic carbon and aggregate stability changes under various forms of land use are needed for the development of sustainable systems. Therefore, comparison of soil samples taken from both agricultural and nearby area close to land-mined fields where no agricultural practices have been done since 1956 can be a good approach to evaluate the effects of tillage and agriculture on soil quality. The objective of this study was to compare tillage, cropping and no tillage effects on some soil-quality parameters. Four different locations along the Turkey–Syria border were selected to determine effects of tillage and cropping on soil quality. Each location was evaluated separately because of different soil type and treatments. Comparisons were made between non-tilled and non-cropped fallow since 1956 and adjacent restricted lands that were tilled about every 2 years but not planted (T) or adjacent lands tilled and planted with wheat and lentil (P). Three samples were taken from the depths of 0–20 and 20–40 cm each site. Soil organic carbon (SOC), pH ,electrical conductivity, water soluble Ca⁺⁺, Mg⁺⁺, CO₃^-2{\rm CO}_{3}^{-2} and HCO₃^-{\rm HCO}_{3}^{-}, extractable potassium (K⁺) and sodium (Na⁺), soil texture, ammonium (NH₄⁺{\rm NH}_{4}^{+}–N) and nitrate (NO₃–N), extractable phosphorous and soil aggregate stability were determined. While the SOC contents of continuous tillage without cropping and continuous tillage and cropping were 2.2 and 11.6 g kg⁻¹, respectively, it was 30 g kg⁻¹ in non-tilled and non-planted site. Tillage of soil without the input of any plant material resulted in loss of carbon from the soil in all sites. Soil extractable NO₃−N contents of non-tilled and non-cropped sites were greatest among all treatments. Agricultural practices increased phosphorus and potassium contents in the soil profile. P₂O₅ contents of planted soils were approximately 20 to 39 times greater than those of non-tilled and non-cropped soils at different sites. FTIR spectra showed that never tilled sites had greater phenol, carboxylic acid, amide, aromatic compounds, polysaccharide and carbohydrates than other treatments.     

Long-term variability of metals from fungicides applied in amended young vineyard fields of La Rioja (Spain)

The long-term variability of total Cu content from fungicides applied in a certified wine region of Spain (La Rioja) and of other metals (Cd, Cr, Ni, Pb, and Zn) was evaluated in three young vineyard soils and subsoils unamended and amended with spent mushroom substrates (SMS) over a 3-year period (2006–2008). SMS is a promising agricultural residue as an amendment to increase the soil organic matter content but may modify the behaviour of metals from pesticide utilisation in vineyards. Fresh and composted SMS was applied each year at a rate of 25 t ha⁻¹ (dry-weight). Copper concentrations in the three unamended soils were 21.2–88.5, 25.5–77.1, and 29.4–78.4 mg kg⁻¹. They exceeded natural Cu concentrations of the region and reference sub-lethal hazardous concentration for soil organism. The concentrations of Cd, Ni, Pb, and Zn were largely below the sub-lethal limits. Thus, although Cu levels were lower than those of established vineyards, vine performance, and productivity might be affected. The variation in behaviour between different amendments for each soil was high, so a generic conclusion could not be drawn. The amendment practice seemed to have caused temporarily Cu mobilization respect to untreated soils. Total zinc concentrations fall within the range of the natural soil of La Rioja and were significantly affected (p < 0.05) especially by fresh state SMS addition, with increasing up to 75% respect to untreated specimen. The results indicated a build-up of fresh sites for metal retention at both surface and subsurface level, although no accumulation of metals was observed in the short-term period. However, the benefit for soils and the negative effects need to be monitored in the long run.     

Water quality and dissolved inorganic fluxes of N,P, SO<Subscript>4</Subscript>, and K of a small catchment river in the Southwestern Coast of India

The southwestern coast of India is drained by many small rivers with lengths less than 250 km and catchment areas less than 6,500 km². These rivers are perennial and are also the major drinking water sources in the region. But, the fast pace of urbanization, industrialization, fertilizer intensive agricultural activities and rise in pilgrim tourism in the past four to five decades have imposed marked changes in water quality and solute fluxes of many of these rivers. The problems have aggravated further due to leaching of ionic constituents from the organic-rich (peaty) impervious sub-surface layers that are exposed due to channel incision resulting from indiscriminate instream mining for construction-grade sand and gravel. In this context, an attempt has been made here to evaluate the water quality and the net nutrient flux of one of the important rivers in the southwestern coast of India, the Manimala river which has a length of about 90 km and catchment area of 847 km². The river exhibits seasonal variation in most of the water quality parameters (pH, electrical conductivity, dissolved oxygen, total dissolved solids, Ca, Mg, Na, K, Fe, HCO₃, NO₂-N, NO₃-N, P _\text-inorg_{\rm \text{-}inorg}, P _\text-tot_{\rm \text{-}tot}, chloride, SO₄, and SiO₂). Except for NO₃-N and SiO₂, all the other parameters are generally enriched in non-monsoon (December–May) samples than that of monsoon (June–November). The flux estimation reveals that the Manimala river transports an amount of 2,308 t y^− 1 of dissolved inorganic nitrogen, 87 t y^− 1 dissolved inorganic phosphorus, and 9246 t y^− 1 of SO₄, and 1984 t y^− 1 K into the receiving coastal waters. These together constitute about 23% of the total dissolved fluxes transported by the Manimala river. Based on the study, a set of mitigation measures are also suggested to improve the overall water quality of small catchment rivers of the densely populated tropics in general and the south western coast in particular.     

Spatial and seasonal distribution of nitrogen in marsh soils of a typical floodplain wetland in Northeast China

Horizontal and profile distributions of nitrogen in marsh soils in different seasons were studied in a typical site within the Erbaifangzi wetland in Northeast China. Results showed that there was higher spatial heterogeneity for nitrate nitrogen (NO₃^--_{3}^{-}-N) and ammonium nitrogen (NH₄⁺_{4}^{+}–N), as well as available nitrogen (AN), in surface soils in July compared to that in September. Relative to July, the mean nitrogen contents in surface soils were slightly higher in September; however, in November, soils contained significantly lower NO₃^--_{3}^{-}-N and NH₄⁺_{4}^{+}–N, higher AN, organic nitrogen (Org-N), and total nitrogen (TN). Except for mineral nitrogen, no significant differences were observed between Org-N and TN contents in September and November. Nitrogen contents generally declined exponentially with depth along soil profiles in three sampling dates (July, September, and November), except for a significant accumulation peak of NO₃^--_{3}^{-}-N at the 20–30 cm depth in September. However, NH₄⁺_{4}^{+}–N contents showed a vertical alternation of “increasing and decreasing” in both July and September, while nearly kept constant with depth in November. The depth ranking of nitrogen showed the shallowest distribution for AN, followed by Org-N and TN, while deeper distributions for NO₃^--_{3}^{-}-N and NH₄⁺_{4}^{+}–N. TN, Org-N, and AN were significantly correlated with soil organic matter and total phosphorus. Soil pH values were significantly correlated with TN and AN contents in surface soils. Clay contents showed significant correlations with nitrogen contents except for NO₃^--_{3}^{-}-N in surface soils and NH₄⁺_{4}^{+}–N in profile soils. However, soil moisture was not significantly correlated with nitrogen contents among all soil samples.     

Effect of long-term application of treated sewage water on heavy metal accumulation in vegetables grown in Northern India

Use of industrial and wastewater for irrigation is on the rise in India and other developing countries because of scarcity of good-quality irrigation water. Wastewaters contain plant nutrients that favour crop growth but leave a burden of heavy metals which can enter the food chain and is a cause of great concern. The present study was undertaken on the long-term impact of irrigation with treated sewage water for growing vegetables and the potential health risk associated with consumption of such vegetable. Treated sewage water (TSW), groundwater (GW), soil and plant samples were collected from peri urban vegetable growing areas of Northern India (Varanasi) and analysed to assess the long-term effect of irrigation with TSW on Cd, Cr, Ni and Pb build-up in soils and its subsequent transfer into commonly grown vegetable crops. Results indicate that TSW was richer in essential plant nutrients but contained Cd, Cr and Ni in amounts well above the permissible limits for its use as irrigation water. Long-term application of TSW resulted in significant build-up of total and DTPA extractable Cd, Cr, Ni and Pb over GW irrigated sites. TSW also resulted in slight lowering in pH, increase in organic carbon (1.6 g kg^− 1) and cation exchange capacity (5.2 cmol kg^− 1). The tissue metal concentration and relative efficiency of transfer of heavy metals from soil to plant (transfer factor) for various groups of vegetables were worked out. Radish, turnip and spinach were grouped as hyper accumulator of heavy metals whereas brinjal and cauliflower accumulated less heavy metals. Health risk assessment by consumption of vegetables grown with TSW indicated that all the vegetables were safe for human consumption. However, significant accumulation of these heavy metals in soil and plant needs to be monitored.     

Spatial variability of soil <Superscript>137</Superscript>Cs in the South Caspian region

In a comprehensive program of environmental radioactivity survey in South Caspian region,¹³⁷Cs inventories in soil has been measured at more than 50 sites in the Iranian northern province of Guilan. This has been the first wide-range survey of soil radionuclide inventories in the narrow band sensitive ecosystem of south Caspian shore. Radioactivity measurements were carried out using HPGe gamma-spectrometry system. The activity concentration of ¹³⁷Cs in surface soil exhibits a mean value of 17.6 ± 9.4 Bq kg⁻¹, with a range of 2.3–41.7 Bq kg⁻¹. In many sites, split-level sampling method has been applied down to a depth of 20 cm. There were found generally two profiles. Most profiles exhibit a negative exponential distribution, while others revealed a clear subsurface peak in 5–10-cm layer. Cesium deposition in the study area has been estimated to be in the range of 0.38–2.9 kBq m⁻² with a mean value of 1.7 kBq m⁻². Distribution patterns of ¹³⁷Cs concentration levels and deposition values have been estimated using Kriging interpolation method. Observed hotspots in deposition pattern coincide with areas of higher precipitation.     

A spectrophotometric assay method for vanadium in biological and environmental samples using 2,4-dinitrophenylhydrazine with imipramine hydrochloride

A simple, rapid, and sensitive method involving the interaction of 2,4-dinitrophenylhydrazine with imipramine hydrochloride in presence of vanadium (V) in sulfuric acid medium has been proposed for the determination of vanadium. The purple-colored product developed showed an absorption maximum at 560 nm and was stable for 24 h. The working curve was linear over the concentration range of 0.1–2.8 μg ml^− 1, with sensitivity of detection of 0.0124 μg ml^− 1. Molar absorptivity and Sandell’s sensitivity were found to be 2.6 × 10⁴ l/mol cm and 0.0039 μg cm^− 1, respectively. The accuracy of the proposed method was assessed by Student’s t test and variance ratio F test, and the results were on par with the reported method. The method was successfully used in the determination of V in water, human urine, soil, and plant samples, and it was free from interference by various concomitant ions.     

Determination of total petroleum hydrocarbons (TPH) in agricultural soils near a petrochemical complex in Guangzhou,China

The total petroleum hydrocarbons (TPH) pollution in regional agricultural soils was investigated. Seventy soil samples collected from surface layers (0–20 cm) and horizons of five selected pedons in the vicinity of a petrochemical complex in Guangzhou, China were analyzed, and the vertical variation and spatial variability of TPH were evaluated. The TPH concentration in top soils around the petrochemical complex ranged from 1,179.3 to 6,354.9 mg kg^− 1, with the average of 2,676.6 mg kg^− 1. Furthermore, significant differences between land-use types showed that the TPH concentration in top soils was strongly influenced by accidental spills. Both the TPH trends in pedons and the identified hot-spot areas also showed that the accidental explosions or burning accidents were mainly responsible for the pollution. The results reported here suggest that the regular monitoring and inspection shall be conducted for safety and to avoid or minimize the accidents, and the effective measures should be taken to remediate the contaminated areas and to assure that the important industrialization of Guangzhou area would not mean human health risks near the petrochemical complex.     

Atmospheric concentrations of nitric acid, sulfur dioxide, particulate nitrate and particulate sulfate, and estimation of their dry deposition on the urban- and mountain-facing sides of Mt. Gokurakuji, Western Japan

Atmospheric concentrations of nitric acid (HNO₃), sulfur dioxide (SO₂), particulate nitrate and particulate sulfate on the urban- and mountain-facing sides of Mt. Gokurakuji were measured from November 2002 to October 2003, in order to evaluate the effects of anthropogenic activity on air quality and dry deposited nitrate and sulfate on the surfaces of pine foliage. The results showed that HNO₃, SO₂ and concentrations were significantly higher (P < 0.05) on the urban-facing side (1.54, 2.48 and 0.65 μg m⁻³, respectively) than the mountain-facing side (0.67, 1.19 and 0.37 μg m⁻³, respectively), while concentrations did not differ significantly between the two sides (urban-facing: 2.80 μg m⁻³; mountain−facing: 2.05 μg m⁻³). Indirect estimates of dry deposition rates of nitrate and sulfate to the surfaces of pine foliage based on the measured concentrations approximately agreed with the measured values determined by the foliar rinsing technique in a previous study. It was found that HNO₃ was the major source (approximately 80%) of dry deposited nitrate on pine foliage, while the contribution from was about equal to that from SO₂. In conclusion, HNO₃ and SO₂ appear to be dominant species reflecting higher dry deposition rates of nitrate and sulfate on the urban-facing side compared to the mountain-facing side of Mt. Gokurakuji.