Cumulative effects of sewage sludge and effluent mixture application on soil properties of a sandy soil under a mixture of star and kikuyu grasses in Zimbabwe

Madyiwa, Simon; Chimbari, Moses John; Nyamangara, Justice; Bangira, Courage

doi:10.1016/s1474-7065(02)00062-1

Cited by 61 publications

(32 citation statements)

References 7 publications

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“…By and large accumulation of micronutrients due to irrigation with DTSW was well below the critical limits prescribed for the phytotoxicity of these micronutrients. Similar findings are in line with the results reported earlier by Madyiwa et al (2002) for the soil irrigated with domestic sewage. …”

Section: : Content Of Micronutrients and Heavy Metals In Vegetablessupporting

confidence: 93%

Impact of Treated Domestic Sewage Irrigation on Crop Yield, Plant Uptake and Soil Properties in Central India

Mhaske

Nikam

2017

IRA-JTE

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Section: : Content Of Micronutrients and Heavy Metals In Vegetablessupporting

confidence: 93%

Impact of Treated Domestic Sewage Irrigation on Crop Yield, Plant Uptake and Soil Properties in Central India

Mhaske

Nikam

2017

IRA-JTE

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“…Cu was mainly present in the organic fraction and enrichment of Cu in subsoils suggested leaching of Cu bound to soluble organics. In a further study of metal-polluted agricultural soils in Zimbabwe, Madyiwa et al (2002) reported that Cu (and Zn) showed higher mobility down the soil profile than Ni and Pb. However, concentrations at depth were relatively low suggesting the metals were unlikely to contaminate groundwater.…”

Section: Mobility and Depth Distributionmentioning

confidence: 96%

The mobility and bioavailability of trace metals in tropical soils: a review

Rieuwerts

2007

Chemical Speciation & Bioavailability

135

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In recent years, initiatives on critical loads of metals have resulted in the development of models to predict critical, i.e. mobile or bioavailable, concentrations of potentially toxic elements in soils. These models have been based on data from temperate soils and, considering the fundamentally different soil chemistry of the major tropical soil types, it is unlikely that such models could be applied successfully in the tropics. In particular, the major tropical soil types, particularly oxisols and ultisols, are distinguished from most temperate soils by low activity clays, low organic matter contents, low pH values and high levels of Fe oxides. The aim of this review paper is to collate existing information on the behaviour of trace metals in tropical soils, particularly in relation to metal mobility and bioavailability, and note differences, where these exist, with temperate soils. The main findings are as follows. The acidic nature of many tropical soils may not, of itself, lead to greater metal solubility. The relatively low organic matter content of tropical soils suggests that it cannot be relied upon to retain metals. However, when it is present, it appears to be important in the retention of copper, lead and zinc. The clay fractions of many tropical soils are dominated by kaolinite which is less able than 2 : 1 layer silicate clays to adsorb metals. However, oxisols and ultisols in particular have relatively high Fe oxides contents and these may be effective in metal sorption. Overall though, soils such as oxisols and ultisols appear to sorb relatively low amounts of added metals, most likely explained by the low activity clay minerals they contain and the rapid decomposition of organic matter incorporated into them. Dominant retention mechanisms, where they occur, are inner and outer sphere adsorption but not precipitation. Cadmium, Cu, Zn and Ni appear to be mobile in tropical soils. Chromium may be mobile in the A horizon but retained in the B horizon. The evidence for Pb points to surface retention, as is often observed for this metal in temperate soils. Metals in contaminated tropical soils appear to be rather bioavailable, judging by the few studies on plant uptake. It should be noted that the above statements are based on a relatively small number of studies. Further work is required if we are to gain an improved understanding of the mobility and bioavailability of trace metals in tropical soils.

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“…This is largely the case of Lake Chivero in Harare, Lake Mutirikwi in Masvingo, and many other catchments within which the major cities of Zimbabwe are located. Many studies have reported considerable damage to the natural environment and potential health risks that were attributed to inadequate treatment and poor disposal of sewage in Zimbabwe (Nyamangara and Mzezewa, 1999;Madyiwa et al, 2002;Mapanda et al, 2005;2007;Ndebele and Mzime, 2012). On the same note, the attempts to relieve pressure on the overloaded sewage treatment works have been hindered by lack of financial capacity, more than lack of technical capacity (Thebe and Mangore, 2012).…”

Section: Introductionmentioning

confidence: 99%

Removal of nutrient and heavy metal loads from sewage effluent using vetiver grass, <i>Chrysopogon zizanioides</i> (L.) Roberty

Mudhiriza¹,

Mapanda²,

Mvumi³

et al. 2015

WSA

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Urban cities in many developing nations face the challenge of relieving the pressure exerted on overloaded sewage treatment works. Apart from limited financial capacity, complementary treatment methods like phyto-extraction of pollutants from the effluent have not been fully exploited, particularly in southern Africa. A study was conducted in Harare, Zimbabwe, to assess the potential of vetiver grass, Chrysopogon zizanioides, in removing N, P, Zn, Mn and Ni loads in sewage effluent from primary clarification, under hydroponic conditions. Vetiver grass was grown from tillers on floating trays suspended in effluent, and the total concentrations of selected parameters were monitored in both effluent and vetiver grass at 0, 7, 14 and 21 days of retention in effluent. Higher pollutant reduction (62-100%) in effluent, with respect to all parameters, under vetiver grass compared to no vetiver treatment (9-27%), was recorded by Day 21. Effluent pH remained stable at 7.44-7.64. Smaller changes were found for N (9.8 from 27.5 mg•ℓ ) by root uptake increased with time at an exponential rate (R 2 , 0.73-0.83). The study established that, while root uptake was a significant feature of the clean-up process, the corresponding high reduction of heavy metals in effluent suggests multiple removal mechanisms, including bio-sorption by microorganisms producing an immobilised microbial biomass on the container wall. A deliberate lowering of effluent pH may increase root uptake thereby possibly reducing the clean-up time and improving effluent quality. There is potential for application of this technology in cities struggling with the cost of conventional sewage treatment.

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Cumulative effects of sewage sludge and effluent mixture application on soil properties of a sandy soil under a mixture of star and kikuyu grasses in Zimbabwe

Cited by 61 publications

References 7 publications

Impact of Treated Domestic Sewage Irrigation on Crop Yield, Plant Uptake and Soil Properties in Central India

Impact of Treated Domestic Sewage Irrigation on Crop Yield, Plant Uptake and Soil Properties in Central India

The mobility and bioavailability of trace metals in tropical soils: a review

Removal of nutrient and heavy metal loads from sewage effluent using vetiver grass, <i>Chrysopogon zizanioides</i> (L.) Roberty

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