Effects of irrigation with raw and differentially diluted sewage and application of primary settled sewage-sludge on wheat plant growth, crop yield, enxymatic changes and trace element uptake

An increase in the concentration of Cu, Zn, Cr and Mn, and a decrease in the activities of aspartate amino transferase, alanine amino transferase and peroxidase were observed in the different fractions of wheat plants, following raw and differentially diluted (66% and 50%) sewage irrigation and dry primary settled sewage-sludge amendments of soils. The grain enrichment efficiencies for Cu, Zn and Mn were significantly low under all experimental conditions. On the other hand, the grain enrichment efficiency for Cr was low under all sewage irrigation conditions only. Except in the earheads of wheat plants from sludge-amended soil, catalase activities were significantly low in roots, stems and earheads of wheat plants, under all other treatment conditions investigated. The decrease in the proteinase activity was statistically significant in roots and earheads of sewage-irrigated plants; the activity in the stem was low following irrigation with raw and 66% sewage only. Proteinase activity was also significantly low in all fractions of wheat plants harvested from soil amended with 20 tonnes of sludge per hectare. The observed results appear to be due to an overall decrease in the metabolic status of the plants following sewage irrigation and sludge amendment of soils. Grain yields, however, were not reduced despite this metabolic effect.     

Removal of heavy metals from a metaliferous water solution by Typha latifolia plants and sewage sludge compost

Typha latifolia plants, commonly known as cattails, were grown in a mixture of mature sewage sludge compost, commercial compost and perlite (2:1:1 by volume). Four Groups (A, B, C and D) were irrigated (once every two weeks) with a solution containing different concentrations of Cu, Ni, and Zn, where in the fifth (group M) tap water was used. At the end of the 10 weeks experimental period substrate and plants were dried, weighed and analysed for heavy metals. The amounts of all three metals removed from the irrigation solution, were substantial. In the roots and leaves/stems of T. latifolia the mean concentration of Zn reached values of 391.7 and 60.8 mg/kg of dry weight (d.w.), respectively. In the substrate of Group D all three metals recorded their highest mean concentrations of 1156.7 mg/kg d.w. for Cu, 296.7 mg/kg d.w. for Ni and 1231.7 mg/kg d.w. for Zn. Linear correlation analyses suggested that there was a linear relationship between the concentration of metals in the solutions and the concentration of metals in the substrates at the end of the experiment. The percentage removal of the metals in the substrate was large, reaching 100% for Cu and Zn in some groups and almost 96% for Ni in group D. The total amount of metals removed by the plants was considerably smaller than that of the substrate, due mainly to the small biomass development. A single factor ANOVA test (5% level) indicated that the build up in the concentration of metals in the roots and the leaves/stems was due to the use of metaliferous water solution and not from the metals pre-existing in the substrate. The contribution of the plants (both roots and leaves/stems) in the removing ability of the system was less than 1%.     

Uptake of carbamazepine by cucumber plants--a case study related to irrigation with reclaimed wastewater

Reclaimed wastewater is an important source of irrigation in semiarid and arid zones. Here we report data on carbamazepine (CBZ) uptake by cucumber plants in hydroponic culture and greenhouse experiments using different soil types irrigated with fresh water or reclaimed wastewater. Data obtained from the hydroponic culture experiments suggest that CBZ is mainly translocated by water mass flow, and thus it is concentrated and accumulated to the largest extent in the mature/older leaves. Carbamazepine concentration in cucumber fruits and leaves was negatively correlated with soil organic matter content. The concentrations of CBZ in the roots and stems were relatively low, and most CBZ in the plant (76-84% of total uptake) was detected in the leaves. A greenhouse experiment using fresh water and reclaimed wastewater spiked, or not, with CBZ at 1 μg L⁻¹ (typical concentration in effluents) revealed that CBZ can be taken up and bioaccumulated from its background concentration in reclaimed wastewater. Bioaccumulation factor (calculated as the ratio of CBZ concentration in the plant to that in the soil solution) for the fruits (0.8-1) was significantly lower than the value calculated for the leaves (17-20).This study emphasizes the potential uptake of active pharmaceutical compounds by crops in organic-matter-poor soils irrigated with reclaimed wastewater and highlights the potential risks associated with this agricultural practice.     

Irrigation of certain Mediterranean plants with heavy metals

The ability of some Mediterranean plant species to absorb heavy metals present in wastewater from treatment plants is researched. Their tolerance to high concentrations of heavy metals is also assessed. Myoporum sp., Nerium oleander and Geranium sp. were irrigated with wastewater, normal irrigation water, and irrigation water enriched with metals. The concentration of metals in the wastewater, irrigation water, in the soil, and in the leaves, tissues and roots of the plants were measured. The results show that treatment of plants with wastewater gives slightly increased concentrations of metals in leaves and roots. In contrast, irrigation with high concentrations of Cu₂₊, Mn₂₊ and Zn₂₊ (up to 1000 mg/1) resulted to significantly higher concentrations of these metals in the roots than in the leaves. However, all plants have been shown to tolerate high concentrations of heavy metals except Nerium oleander, which exhibited strong toxicity in leaves. The tolerance of these Mediterranean plant species to polluted environments allows them to be irrigated by wastewater from treatment plants, so as to achieve the best environmental rehabilitation of desertified Mediterranean areas.     

Saline irrigation and Zn amendment effect on Cd phytoavailability to Swiss chard (Beta vulgaris L.) grown on a long-term amended agricultural soil: a human risk assessment

Crops, particularly in the Northeast region of Mexico, have to cope with increasing soil salinization due to irrigation. Chloride (Cl^?) concentration has been strongly related to enhance cadmium (Cd) uptake by plants due to increased solubility in the soil solution. The effect of irrigation with slightly saline water from a local well was evaluated in this work on the accumulation and translocation of Cd in Swiss chard (Beta vulgaris L.) grown in soil historically amended with stabilized sewage sludge under a regime of phosphorus and zinc fertilization. A factorial pot experiment was conducted with two phosphate fertilizer levels (PF, 0 and 80 kg ha^?1 dry soil, respectively), two Zn levels (0 and 7 kg ha^?1 dry soil), and two sources of water for irrigation deionized water (DW) and slightly saline well water (WW) from an agricultural site. Additionally, a human risk assessment for Cd ingestion from plants was assessed. Results showed that Cl^? salinity in the WW effectively mobilized soil Cd and increased its phytoavailability. A higher level of Cd was found in roots (46.41 mg kg^?1) compared to shoots (10.75 mg kg^?1). Although the total content of Cd in the edible parts of the Swiss chard irrigated with WW exceeded permissible recommended consumption limit, bioavailable cadmium in the aboveground parts of the plant in relation to the total cadmium content was in the range from 8 to 32 %. Therefore, human health risks might be overestimated when the total concentration is taken into account.     

Factors impacting on pharmaceutical leaching following sewage application to land

Sewage effluent application to land is a treatment technology that requires appropriate consideration of various design factors. Soil type, level of sewage pre-treatment and irrigation rate were assessed for their influence on the success of soil treatment in removing pharmaceuticals remaining after conventional sewage treatment. A large scale experimental site was built to assess treatment performance in a realistic environment. Of the factors investigated, soil type had the biggest impact on treatment performance. In particular, carbamazepine was very efficiently removed (>99%) when irrigated onto a volcanic sandy loam soil. This was in contrast to irrigation onto a sandy soil where no carbamazepine removal occurred after irrigation. Differences were likely caused by the presence of allophane in the volcanic soil which is able to accumulate a high level of organic matter. Carbamazepine apparent adsorption distribution coefficients (K(d)) for both soils when irrigated with treated sewage effluent were determined as 25 L kg(-1) for the volcanic soil and 0.08 L kg(-1) for the sandy soil. Overall, a volcanic soil was reasonably efficient in removing carbamazepine while soil type was not a major factor for caffeine removal. Removal of caffeine, however, was more efficient when a partially treated rather than fully treated effluent was applied. Based on the investigated pharmaceuticals and given an appropriate design, effluent irrigation onto land, in conjunction with conventional sewage treatment may be considered a beneficial treatment for pharmaceutical removal.     

Copper contamination in paddy soils irrigated with wastewater

Copper (Cu) contamination was investigated in paddy soils where Cu-rich wastewater (12 mg Cu/l) was used for irrigation. The results showed that Cu contamination increased the soil Cu content from 17.0 mg Cu/kg in the non-wastewater irrigated soils (NWIS) to 101.2 mg Cu/kg in the wastewater irrigated soils (WIS), and Cu accumulated mostly in the surface layer (0-10 cm) of the paddy soil. The average Cu contents in brown rice, rice hull and rice straw from NWIS were 1.4, 7.3 and 14.5 mg Cu/kg, while those from WIS were 15.5, 133.2, and 101.4 mg Cu/kg, respectively. Correlation analysis revealed that the relationship between the Cu content in the rice straw and the rice hull with the total Cu content of the soil could be described by an exponential function (R2 = 0.921 and 0.831, respectively; P <0.01). Rice plants grown in the WIS showed symptoms of black roots, less effective tiller, etc. Subsequently, the rice yield decreased by 18-25%, compared with that grown in NWIS.     

Characteristics of heavy metals in soils and grains of wheat and maize from farmland irrigated with sewage

The farmland irrigation with the sewage is a common and better pathway to save the resource of groundwater in Northern China. The investigation was conducted in the farmland along the Fuhe River to explore characteristics of heavy metals in soils and grains of wheat and maize from a long-term sewage-irrigated area of Baoding region. The results showed that the topsoil with long-term sewage irrigation accumulated more Cd, Pb, and Hg compared with that of soil irrigated with groundwater and their corresponding natural background values. Cd concentrations in 48% of sewage-irrigated soil samples exceeded the Chinese safety limitation at 0.6 mg/kg, but less Cd accumulated in crop grains and did not pose the potential health risk. On the contrary, Pb levels in soils irrigated with sewage were lower than the safety limitation but Pb concentrations in 24% of wheat grain samples exceeded the Chinese national safety limit. Long-term sewage irrigation did not increase As, Cr, and Ni concentrations in soils or crop grains. The target hazard quotient (THQ) of heavy metals in edible grains of crops was selected to assess their risk to human health. Total THQ values were higher than 1.0 for the wheat samples from sewage-irrigated area and both sewage-irrigated and smelter-impacted areas, and As is the main contributor to the total THQ and posed the potential risk to human health. Therefore, the accumulation of Cd, Pb, Hg, and As in soils and crops in sewage-irrigated area should be monitored continuously to ensure food safety and security.

     

Ecological impacts of the N-viro biosolids land-application for wild blueberry (Vaccinium angustifolium. Ait) production in Nova Scotia

Land application of biosolids from processed sewage sludge may deteriorate soil, water, and plants. We investigated the impact of the N-Viro biosolids land-application on the quality of the soil water that moved through Orthic Humo-Ferric Podzols soil of Nova Scotia (NS) at the Wild Blueberry Research Institute, Debert, NS Canada. In addition, the response of major soilproperties and crop yield was also studied. Wild blueberry (Vaccinium angustifolium. Ait) was grown under irrigated and rainfed conditions in 2008 and 2009. Four experimental treatments including (i) NI: N-Viro irrigated, (ii) NR: N-Viro rainfed, (iii) FI: inorganic fertilizer irrigated, and (iv) FR: inorganic fertilizer rainfed (control) were replicated 4 times under randomized complete block design. Soil samples were collected at the end of each year and analyzed for changes in cation exchange capacity (CEC), soil organic matter (SOM), and pH.Soil water samples were collected four times during the study period from the suction cup lysimeters installed within and below crop root zone at 20 and 40 cm depths, respectively. The samples were analyzed for a range of water quality parameters including conductance, hardness, pH, macro- and micronutrients, and the infectious pathogens Escherichia coli (E. coli) and salmonella. Berries were harvested for fruit yield estimates. Irrigation significantly increased CEC during 2008 and the soil pH decreased from 4.93 (2008) to 4.79 (2009). There were significant influences of irrigation, fertilizer, and their interaction, in some cases, on most of the soil water quality parameters except on the infectious bacteria. No presence of E. coli or salmonella were observed in soil and water samples, reflecting the absence of these bacteria in biosolids used in this experiment. Nutrient concentration in the soil water samples collected from the four treatments were higher in the sequence NI > NR > FI > FR. The irrigation treatment had significant effect on the unripe fruit yield. We conclude that the comparable performance of N-Viro biosolids and the increasing prices of inorganic fertilizers would compel farmers to use economically available N-Viro biosolids that, coupled with the supplemental irrigation, did not deteriorate the studied soil properties, soil water quality, and the wild blueberry yield during this experiment.     

EDTA and urease effects on Hg accumulation by Lepidium sativum

The phytoextraction process was conducted under laboratory conditions with the use of garden cress plants (Lepidium sativum). The experiment was carried out in a model soil, which was characterized before conducting the process. Inorganic forms of mercury (HgCl(2), HgSO(4), Hg(NO(3))(2)) were used for contamination of the soil. The phytoextraction process was conducted after EDTA application to the soil and after urease application. Also the influence of simultaneous addition of ethylenediaminetetraacetic acid (EDTA) and urease into the soil on phytoextraction process was measured. In all variants of phytoextraction process the total mercury concentrations in roots, stems and leaves of garden cress were determined. The result showed that garden cress accumulated mercury from soil. The overall maximum concentration of mercury in its compounds was found in roots of the plant. In all cases, before addition of urease and EDTA, the translocation process and distribution of mercury in the plant tissues were limited. The addition of urease caused an increase of enzyme activity in the soil and at the same time caused an increase of mercury concentration in plant tissues. Application of EDTA increased solubility of mercury and caused an increase of metal accumulation by plants. After simultaneous addition of EDTA and urease into the soil garden cress accumulated about 20% of total mercury concentration in the soil. Most of mercury compounds were accumulated in leaves and stems of the plants (46.0-56.9% of total mercury concentration in the plant tissues).     

Field controlled experiments of mercury accumulation in crops from air and soil

Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation.     

Effect of coal mine soil contamination on the elemental uptake and distribution in two edible Amaranthus species, A. dubius and A. hybridus

The impact of coal mine dump contaminated soil on the elemental uptake by two edible plants, namely, Amaranthus dubius (red herbs) and Amaranthus hybridus (green herbs), was studied by investigating their response and ability to tolerate and accumulate varying levels of elements in their roots and shoots. The vegetation was grown on varying amounts of contaminated soil, viz. 0%, 5%, 15%, 25% w/w using coal mine dump soil. The soil was analyzed for soil pH, cation exchange capacity (CEC), soil organic matter (SOM), moisture content, and selected heavy metals. The distribution of six metals, namely, Pb, Cd, Hg, Ni, Mn, and Fe, in roots, stem, and leaves of the plants was determined in two stages of growth after 5 weeks and 10 weeks. All soil and plant samples were microwave digested and subjected to heavy metal analysis using the ICP-OES, GFAAS, and CVAAS. The pH of the coal mine dump contaminated soil decreased with an increase in contamination. Both the SOM and CEC values decreased, which increases the availability of elements, by providing more binding sites in the soil. Relatively, the red herbs had higher elemental concentrations than the green herbs. Both plants recorded high manganese accumulation. No mercury was detected in the soils or plants.     

The influence of radical architecture on cadmium bioaccumulation in the black mangrove, Avicennia germinans L

Two groups of Avicennia germinans plants with differences in the radical architecture were exposed under hydroponic conditions to 95ppm of cadmium (Cd) for a period of 24h. Later, Cd concentration in roots, stems and leaves was determined by graphite furnace atomic absorption spectrophotometry. Our results showed that, for both groups of plants, the roots accumulated higher concentration of Cd as compared to stems and leaves, though, the plants of group B displayed enhanced radical architecture, better growth performance, and lower Cd concentration as compared to plants of group A. In contrast, low values of leaves/roots Cd transportation index, and bioaccumulation factor were found in plants of group B. These results suggest that the higher radical architecture developed in plants of group B might better adjust the uptake of Cd as a result of an integrated network of multiple response processes for instances, production of organic acids, antioxidative replay, cell-wall lignification and/or suberization. Further studies will be focused in understanding the role of the radical system in mangrove plants with the rhizosphere activation and root adsorption to soil Cd under natural conditions.     

Effects of sewage sludge amendment on heavy metal accumulation and consequent responses of Beta vulgaris plants

Use of sewage sludge, a biological residue produced from sewage treatment processes in agriculture is an alternative disposal technique of waste. To study the usefulness of sewage sludge amendment for palak (Beta vulgaris var. Allgreen H-1), a leafy vegetable and consequent heavy metal contamination, a pot experiment was conducted by mixing sewage sludge at 20% and 40% (w/w) amendment ratios to the agricultural soil. Soil pH decreased whereas electrical conductance, organic carbon, total N, available P and exchangeable Na, K and Ca increased in soil amended with sewage sludge in comparison to unamended soil. Sewage sludge amendment led to significant increase in Pb, Cr, Cd, Cu, Zn and Ni concentrations of soil. Cd concentration in soil was found above the Indian permissible limit in soil at both the amendment ratios.

The increased concentration of heavy metals in soil due to sewage sludge amendment led to increases in heavy metal uptake and shoot and root concentrations of Ni, Cd, Cu, Cr, Pb and Zn in plants as compared to those grown on unamended soil. Accumulation was more in roots than shoots for most of the heavy metals. Concentrations of Cd, Ni and Zn were more than the permissible limits of Indian standard in the edible portion of palak grown on different sewage sludge amendments ratios. Sewage sludge amendment in soil decreased root length, leaf area and root biomass of palak at both the amendment ratios, whereas shoot biomass and yield decreased significantly at 40% sludge amendment. Rate of photosynthesis, stomatal conductance and chlorophyll content decreased whereas lipid peroxidation, peroxidase activity and protein and proline contents, increased in plants grown in sewage sludge-amended soil as compared to those grown in unamended soil.

The study clearly shows that increase in heavy metal concentration in foliage of plants grown in sewage sludge-amended soil caused unfavorable changes in physiological and biochemical characteristics of plants leading to reductions in morphological characteristics, biomass accumulation and yield. The study concludes that sewage sludge amendment in soil for growing palak may not be a good option due to risk of contamination of Cd, Ni and Zn and also due to lowering of yield at higher mixing ratio.     

Heavy metal uptake by two edible Amaranthus herbs grown on soils contaminated with lead, mercury, cadmium, and nickel

The uptake of an element by a plant is primarily dependent on the plant species, its inherent controls, and the soil quality. Amaranthus hybridus (green herbs) and Amaranthus dubius (red herbs) were chosen to investigate their response and ability to accumulate and tolerate varying levels of elements in their roots and shoots. Red herbs and green herbs were grown in soil pots contaminated with three mixtures of Cd(II), Ni(II), Pb(II), and Hg(II). Plants in the control treatment were grown in the absence of the heavy metals mixture. The distribution of Cd, Ni, Pb, and Hg in the plants (in roots, stems, and leaves) was determined in two stages. Stage 1, after 5 weeks of plant growth and stage 2, full grown after 10 weeks of growth. In the red herbs the Cd concentration in the leaves at stage 2 was 150 ppm and was present in higher concentrations than Ni, Hg, and Pb. At the highest contamination level, in the green herbs plant, Hg was present in the highest concentration in the root, i.e., 336 ppm at stage 1, while the level in the leaves was 7.12 ppm. Both the green and red herbs species showed an affinity for Ni and Cd with moderate to high levels detected in the leaves, respectively.     

Glucosinolates in collard greens grown under three soil management practices

Glucosinolates (GSLs, β-D-thioglucoside-N-hydroxysulfates) are polar compounds present in varying amounts in members of the Brassicaceae family. They suppress soil-borne pests due to the biofumigant properties of the highly toxic isothiocyanates present in Brassica vegetables. The objectives of this investigation were to: (1) assess variation in GSLs concentrations among collard plants grown under three soil management practices: sewage sludge (SS) mixed with native soil, chicken manure (CM) mixed with native soil, and no-mulch (NM) native soil, (2) quantify GSLs concentrations in collard roots, leaves, and stems at harvest for potential use of their crude extracts in plant protection, and (3) assess myrosinase activity in soil amended with CM and SS mixed with native soil. Separation of GSLs was accomplished by adsorption on a DEAE-Sephadex ion exchange resin using disposable pipette tips filled with DEAE, a weak base, with a net positive charge when ionized and exchange anions such as GSLs (hydrophilic plant secondary metabolites). Quantification of total GSLs was based on inactivation of collard endogenous myrosinase and liberation of the glucose moiety from the GSLs molecule by addition of standardized myrosinase and colorimetric determination of the liberated glucose moiety. Across all treatments, SS and CM increased soil organic matter content from 2.2% in native soil to 4.2 and 6.5%, respectively. GSLs concentrations were significantly greater in collard leaves (30.9 µmoles g^?1 fresh weight) compared to roots and stems (7.8 and 1.2 µmoles g^?1 fresh weight), respectively. Leaves of collard grown in soil amended with SS contained the greatest concentrations of GSLs compared to leaves of plants grown in CM and NM treatments. Accordingly, leaves of collard plants grown in soil amended with SS could play a significant role in sustainable agriculture as alternative tools for soil-borne disease management in conventional and organic agriculture.     

Ecological impacts of the N-viro biosolids land-application for wild blueberry (Vaccinium angustifolium. Ait) production in Nova Scotia

Land application of biosolids from processed sewage sludge may deteriorate soil, water, and plants. We investigated the impact of the N-Viro biosolids land-application on the quality of the soil water that moved through Orthic Humo-Ferric Podzols soil of Nova Scotia (NS) at the Wild Blueberry Research Institute, Debert, NS Canada. In addition, the response of major soilproperties and crop yield was also studied. Wild blueberry (Vaccinium angustifolium. Ait) was grown under irrigated and rainfed conditions in 2008 and 2009. Four experimental treatments including (i) NI: N-Viro irrigated, (ii) NR: N-Viro rainfed, (iii) FI: inorganic fertilizer irrigated, and (iv) FR: inorganic fertilizer rainfed (control) were replicated 4 times under randomized complete block design. Soil samples were collected at the end of each year and analyzed for changes in cation exchange capacity (CEC), soil organic matter (SOM), and pH.Soil water samples were collected four times during the study period from the suction cup lysimeters installed within and below crop root zone at 20 and 40 cm depths, respectively. The samples were analyzed for a range of water quality parameters including conductance, hardness, pH, macro- and micronutrients, and the infectious pathogens Escherichia coli (E. coli) and salmonella. Berries were harvested for fruit yield estimates. Irrigation significantly increased CEC during 2008 and the soil pH decreased from 4.93 (2008) to 4.79 (2009). There were significant influences of irrigation, fertilizer, and their interaction, in some cases, on most of the soil water quality parameters except on the infectious bacteria. No presence of E. coli or salmonella were observed in soil and water samples, reflecting the absence of these bacteria in biosolids used in this experiment. Nutrient concentration in the soil water samples collected from the four treatments were higher in the sequence NI > NR > FI > FR. The irrigation treatment had significant effect on the unripe fruit yield. We conclude that the comparable performance of N-Viro biosolids and the increasing prices of inorganic fertilizers would compel farmers to use economically available N-Viro biosolids that, coupled with the supplemental irrigation, did not deteriorate the studied soil properties, soil water quality, and the wild blueberry yield during this experiment.     

Effect of Coal Mine Soil Contamination on the Elemental Uptake and Distribution in Two Edible Amaranthus Species,A. dubius and A. hybridus

The impact of coal mine dump contaminated soil on the elemental uptake by two edible plants, namely, Amaranthus dubius (red herbs) and Amaranthus hybridus (green herbs), was studied by investigating their response and ability to tolerate and accumulate varying levels of elements in their roots and shoots. The vegetation was grown on varying amounts of contaminated soil, viz. 0%, 5%, 15%, 25% w/w using coal mine dump soil. The soil was analyzed for soil pH, cation exchange capacity (CEC), soil organic matter (SOM), moisture content, and selected heavy metals. The distribution of six metals, namely, Pb, Cd, Hg, Ni, Mn, and Fe, in roots, stem, and leaves of the plants was determined in two stages of growth after 5 weeks and 10 weeks. All soil and plant samples were microwave digested and subjected to heavy metal analysis using the ICP-OES, GFAAS, and CVAAS. The pH of the coal mine dump contaminated soil decreased with an increase in contamination. Both the SOM and CEC values decreased, which increases the availability of elements, by providing more binding sites in the soil. Relatively, the red herbs had higher elemental concentrations than the green herbs. Both plants recorded high manganese accumulation. No mercury was detected in the soils or plants.     

Irrigation of treated wastewater in Braunschweig, Germany: an option to remove pharmaceuticals and musk fragrances

In this study the fate of pharmaceuticals and personal care products which are irrigated on arable land with treated municipal wastewater was investigated. In Braunschweig, Germany, wastewater has been irrigated continuously for more than 45 years. In the winter time only the effluent of the sewage treatment plant (STP) of Braunschweig is used for irrigation, while during summer digested sludge is mixed with the effluent. In the present case study six wells and four lysimeters located in one of the irrigated agricultural fields were monitored with regard to the occurrence of 52 pharmaceuticals and two personal care products (PPCPs; e.g. betablockers, antibiotics, antiphlogistics, carbamazepine, musk fragrances, iodinated contrast media (ICM) and estrogens). No differences in PPCP pollution of the groundwater were found due to irrigation of STP effluents with and without addition of digested sludge, because many polar compounds do not sorb to sludge and lipophilic compounds are not mobile in the soil-aquifer. Most of the selected PPCPs were never detected in any of the lysimeter or groundwater samples, although they were present in the treated wastewater irrigated onto the fields. In the groundwater and lysimeter samples primarily the ICM diatrizoate and iopamidol, the antiepileptic carbamazepine and the antibiotic sulfamethoxazole were detected up to several mugl(-1), while the acidic pharmaceuticals, musk fragrances, estrogens and betablockers were likely sorbed or transformed while passing the top soil layer. Potential estrogenic effects are likely to disappear after irrigation, since the most potent steroid estrogens were not measurable.     

Heavy Metal Uptake by Two Edible Amaranthus Herbs Grown on Soils Contaminated with Lead,Mercury, Cadmium,and Nickel

The uptake of an element by a plant is primarily dependent on the plant species, its inherent controls, and the soil quality. Amaranthus hybridus (green herbs) and Amaranthus dubius (red herbs) were chosen to investigate their response and ability to accumulate and tolerate varying levels of elements in their roots and shoots. Red herbs and green herbs were grown in soil pots contaminated with three mixtures of Cd(II), Ni(II), Pb(II), and Hg(II). Plants in the control treatment were grown in the absence of the heavy metals mixture. The distribution of Cd, Ni, Pb, and Hg in the plants (in roots, stems, and leaves) was determined in two stages. Stage 1, after 5 weeks of plant growth and stage 2, full grown after 10 weeks of growth. In the red herbs the Cd concentration in the leaves at stage 2 was 150 ppm and was present in higher concentrations than Ni, Hg, and Pb. At the highest contamination level, in the green herbs plant, Hg was present in the highest concentration in the root, i.e., 336 ppm at stage 1, while the level in the leaves was 7.12 ppm. Both the green and red herbs species showed an affinity for Ni and Cd with moderate to high levels detected in the leaves, respectively.