Increasing shortages of fresh water has led to greater use of treated wastewater for irrigation of crops. This study evaluates the spatial variability of soil properties after irrigation with wastewater and freshwater. Geostatistical techniques were used to identify the variability of soil properties at the different sites. A set of physical and chemical soil properties were measured including total nitrogen (TN), total phosphorus (TP), organic matter (OM) and soil moisture. The TN concentration levels varied from 567 to 700 mg·kg-1, while OC levels ranged from 7.3 to 16.3 mg·kg-1 in wastewater-irrigated zones. The concentration levels of TP were between 371.53 and 402.88 mg·kg-1 for the wastewater-irrigated sites. Wastewater irrigation resulted in higher TN, TP and OM concentrations by 18.4%, 8% and 25%, respectively. The highest TN and OM occurred along the wastewater trunk. It was also observed that nitrogen concentrations correlate with the soil's organic matter. The increase of salinity may be associated with the increase of pH, which might suggest that a reduction of pH will be beneficial for plant growth due to the decrease of salinity. The average concentrations of nitrogen in topsoil were higher than those in subsurface soils in irrigated areas. Such differences of the N profile might be due to variations in organic matter content and microbial populations. Consistent with TN and OM, soil C:N decreased significantly with an increase of depth. This phenomenon possibly reflects a greater degree of breakdown and the older age of humus stored in the deeper soil layers. The analysis of pH levels at different depths for the three sites showed that pH values for wastewater irrigation were slightly lower than the controlled sites at the same depths. 相似文献
Contaminated groundwater and a riverine sediment core heavily affected by the same industrial point source were analysed for
hexachlorocyclohexanes (HCH) and its degradation products. A detailed quantification by GC/MS revealed contamination levels
up to 730 μg/L and 396 ng/g in sum for the water and sediment samples, respectively. The isomer pattern differed significantly
in both compartments. The ground water samples were depleted in γ-HCH, whereas a significant loss of α-HCH was evident in
the sediments as compared to the technical composition. The data obtained revealed interesting insights into the transformation
behaviour and fate of HCH mixtures in anaerobic environmental compartments. In the affected groundwater system an ongoing
microbial degradation was pointed out by the identification of indicative anaerobic metabolites. On the contrary in the sedimentary
system a high environmental stability or rather a hindered degradation was observed as indicated by unaltered concentration
levels as compared to production rates as well as by the absence of metabolites. Interestingly, the environmental fate of
HCH in subaquatic sediments as well as in anaerobic ground water differs highly in contrast to the behaviour in anaerobic
soil or surface water systems. Further on, it has to be stated, that the knowledge about the long-term behaviour of HCH residues
in sedimentary material under anaerobic conditions is rather limited so far. 相似文献
Previous research has demonstrated that many urban soils are enriched in Pb, Cd and Zn. Culture of vegetable crops in these soils could allow transfer of potentially toxic metals to foods. Tanya lettuce (Lactuca sativa L.) was grown in pots of five urban garden soils and one control agricultural soil to assess the effect of urban-soil metal enrichment, and the effect of soil amendments, on heavy metal uptake by garden vegetables. The amendments included NPK fertilizer, limestone, Ca(H2PO4)2, and two rates of limed sewage sludge compost. Soil Cd ranged from 0.08 to 9.6 mg kg–1; soil Zn from 38 to 3490 mg kg–1; and soil Pb from 12 to 5210 mg kg–1. Lettuce yield on the urban garden soils was as great as or greater than that on the control soil. Lettuce Cd, Zn and Pb concentrations increased from 0.65, 23, and 2.2 mg kg–1 dry matter in the control soil to as high as 3.53, 422 and 37.0 mg kg–1 on the metal-rich urban garden soils. Adding limestone or limed sewage sludge compost raised soil pH and significantly reduced lettuce Cd and Zn, while phosphate fertilizer lowered soil pH and had little effect on Zn but increased Cd concentration in lettuce. Urban garden soils caused a significant increase in lettuce leaf Pb concentration, especially on the highest Pb soil. Adding NPK fertilizer, phosphate, or sludge compost to two high Pb soils lowered lettuce Pb concentration, but adding limestone generally did not. On normally fertilized soils, Pb uptake by lettuce was not exceptionally high until soil Pb substantially exceeded 500 mg kg–1. Comparing garden vegetables and soil as potential sources of Pb risk to children, it is clear that the risk is greater through ingestion of soil or dust than through ingestion of garden vegetables grown on the soil. Urban dwellers should obtain soil metal analyses before selecting garden locations to reduce Pb risk to their children. 相似文献
This study is to isolate the effluent strain of VAM fungi from polluted soils of sugar mill effluents. Analysis showed that pH and EC was more but the organic matter is less when compared to non-polluted soils. Even though there was low P content that enhances the mycorrhizal infection, the percent of root colonization was less than 75% in polluted study site. The number of VAM propagules and its distribution were also greatly affected due to various factors. Nine different VAM species were isolated and identified from the polluted study site. Using Allium cepa L. as the host plant the efficiency of the native effluent tolerant strains of VAM fungi isolated from the polluted study site was determined. Highest growth rate, high dry weight of gram per plant and increased growth was observed in the order of Glomus intraradices followed by Gigaspora margarita and Glomus fasciculatum. Consequence of the study clearly showed that Glomus intraradices was the efficient strain in sugar mill effluent polluted areas. 相似文献
The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has become an increasingly serious global public health issue. This study investigated the distribution characteristics and influencing factors of ARB and ARGs in greenhouse vegetable soils with long-term application of manure. Five typical ARGs, four heavy metal resistance genes (MRGs), and two mobile genetic elements (MGEs) were quantified by real-time quantitative polymerase chain reaction (qPCR). The amount of ARB in manure-improved soil greatly exceeded that in control soil, and the bacterial resistance rate decreased significantly with increases in antibiotic concentrations. In addition, the resistance rate of ARB to enrofloxacin (ENR) was lower than that of tylosin (TYL). Real-time qPCR results showed that long-term application of manure enhanced the relative abundance of ARGs in vegetable soils, and the content and proportion of quinolone resistance genes were higher than those of macrolide resistance genes. Redundancy analysis (RDA) showed that qepA and qnrS significantly correlated with total and available amounts of Cu and Zn, highlighting that certain heavy metals can influence persistence of ARGs. Integrase gene intI1 correlated significantly with the relative abundance of qepA, qnrS, and ermF, suggesting that intI1 played an important role in the horizontal transfer of ARGs. Furthermore, there was a weakly but not significantly positive correlation between specific detected MRGs and ARGs and MGEs. The results of this study enhance understanding the potential for increasing ARGs in manure-applied soil, assessing ecological risk and reducing the spread of ARGs.
Field survey was conducted to assess the quality of underground water in four major industrial areas of Hyderabad, Andhra Pradesh, and viz., Patancheru, Katedhan, Nacharam and Jeedimetla. Ground water samples were collected from wells at different lateral distances from the effluent streams i.e., starting from a minimum distance of 20 meters to a maximum distance of 620 meters from the effluent streams and analysed for different characteristics. The survey revealed that indiscriminate disposal of the effluent of industrial complexes around Hyderabad has aggrevated the acidity, EC, TDS, COD, Cl-, SO4(2-), PO4(3-), NO3-, F and heavy metals in the ground waters. As the sampling distance from the polluting stream increased a gradual improvement in the quality of ground water was noticed. 相似文献
An incubation experiment was conducted to monitor effect of sewage sludge application on changes in numbers of faecal coliforms in soils over time after sludge application and evaluate the hygiene risks. Soil faecal coliform counts were made after 1, 7, 14, 28, 56 and 84 days of incubation. The faecal coliform counts in the sludge-treated soils decreased substantially with time and were similar to those in the untreated controls after incubation for 56 days. Land application of air-dried sludges increased the hygiene risks due to the re-growth of faecal coliforms, and the counts of faecal coliforms in soil treated with air dried sludge from Suzhou (91% DM) were 50 times higher than in soils with fresh dewatered sludge from Suzhou (15% DM) after 7 days of incubation. The main factors affecting the changes in faecal coliform counts were sludge type and incubation time. Sludge type determined the faecal coliform counts and the ability of the faecal coliforms to re-establish, and indigenous microorganisms competed with the faecal coliforms for nutrients during the incubation process. 相似文献
We studied polycyclic aromatic hydrocarbons (PAHs) in crop soils amended with 1000 tonnes dry weight of sewage sludges per
10,000 m2 from 1974 to 1992, then after sludges addition from 1993 to 1999. The absence of variations of total PAHs levels of control
soils, averaging at 123 μg/Kg, shows the absence of horizontal contamination. During sludges addition, the total PAHs levels
in amended soils increased from 232 to 402 μg/Kg. Seven years after sludges addition, it decreased to 275 μg/Kg, which is
still more than twice –the levels of control soils. This finding shows that sludges PAHs are preserved in crop soils for long
periods of time, on a human scale. 相似文献
Thasos Island has a long history of metalliferous mining, the first mining activities having been initiated by the Phoenicians during the seventh century. The mineralogy of the mineralisation includes primary minerals (galena, sphalerite) and secondary oxidised minerals (smithsonite, cerussite). In the soils studied only secondary minerals were found. Clay minerals (kaolinite, illite, montmorillonite, mixed layer clays), plagioclase, calcite and dolomite are also present in the soils. Contamination derived from the old mining sites results in extremely high levels of Pb, Zn, Mn, Fe, As, Sb, Ag, Cd in soils in the vicinity of the old workings. Since many of the Thasos mining sites are in, or adjacent to, areas of agricultural land, plants growing on the polluted sous have increased concentrations of heavy metals. This may well have a possible effect on livestock. 相似文献
The influence of three effluent organic matter (EfOM) model compounds, humic acid (HA), bovine serum albumin (BSA), and sodium alginate (AGS), on the ozonation of bezafibrate (BF), a typical pharmaceutical and personal care product (PPCP), was investigated. The results show that ozonation efficiently removed BF from aqueous solution with removal efficiencies>95% within 8 min for all conditions. The reaction rate of BF decreased with increasing model compounds concentrations and the influence was more pronounced for HA and BSA, while less pronounced for AGS. Although BF concentration was significantly reduced, the degree of mineralization achieved was only approximately 11%. The addition of HA and BSA improved the mineralization of the solution, while the influence of AGS was minor. The acute toxicity of BF solution during ozonation was determined using the Luminescent bacteria test, and the toxicity exhibited an initial increase and a successive reduction. An overall decreased acute toxicity was observed with an increase of HA. The presence of BSA increased the formation rate of toxicity intermediates and resulted in inhibition peak forward. 相似文献
Chenopodium album is a weed commonly consumed by North Indian population as vegetable. Plants are known to accumulate toxins from their environment. Presently, the leaf homogenates of these plants growing in a tubewell irrigated field and a sewage irrigated field were evaluated for cytotoxicological effects in Allium root tip assay. Studies revealed that Chenopodium album was mildly mitodepressive in nature and was capable of inducing chromosomal aberrations. The leaf homogenate of the plants growing in sewage irrigated fields induced more quantum of aberrations than the plants from the control site. This has a direct bearing on consumability of sewage grown vegetables and fodder. 相似文献
Monosodium glutamate (MSG) effluent was sampled from three MSG mills and 21 metal elements were measured with a inductively coupled plasma (ICP) Spectrometer. The total metal concentration of each MSG wastewater sample was 19192, 3190 and 3161 mg/L respectively. Compared with the water quality standard issued by the Chinese Government and the World Health Organization (WHO), some values were found to exceed the standards. The 24hr‐LC50, 48hr‐LC50, 72hr‐LC50 and 96hr‐LC50 to the fish Ctenopharyngodon idellus were 6.9%, 3.2%, 2.5% and 1.4% MSG wastewater individually. The specific growth rate for photosynthetic bacteria (PSB) Rhodopseudomonas sphaeroides was inhibited by the metals in MSG wastewater. Therefor the MSG wastewater should not be discharged into drinking, irrigation and fishery water systems, moreover it cannot be treated by general biological processes efficiently. How to develop an effective biotechnique for the utilization of organic pollutants in MSG effluent will also be discussed in this paper. 相似文献