Metals in urban gardens ‐ effect of lime and sludge

Preer, James R.; Abdi, Ahmed N.; Sekhon, Harkewal S.; Murchison, George B.

doi:10.1080/10934529509376320

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…Gardeners can attempt to mitigate cadmium contamination by using biochar or adding zinc to the soil [8]. Background cadmium levels in the soil are 0.6 mg/kg, and the recommended cadmium intake is 70 µg per day [41]. Urban garden soil can exceed the background level [5,25].…”

Section: Cadmium (Cd)mentioning

confidence: 99%

Trace Metal Contamination in Community Garden Soils across the United States

Malone,

Shakya

2024

Sustainability

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Community gardens are often seen as a means for producing sustainable food resources in urban communities. However, the presence of trace metals and metalloids such as lead, arsenic, and cadmium in urban soils poses a health risk to gardeners who participate in urban community gardens. They are exposed to these contaminates through multiple exposure pathways such as inhalation and ingestion directly through soil or through crops grown in the soil. Hot spots of soil contamination are higher in areas of cities with greater minority populations and lower incomes. This paper reviews the state of heavy metal contamination in community garden soils across the United States. This paper outlines the major sources of heavy metals in urban soils, exposure pathways, the ways to reduce heavy metal levels in garden soils, the means to slow down the uptake of heavy metals, and limit the exposure of these contaminates. The application of biochar and compost, implementing raised beds, and maintaining a natural pH are all examples of ways to mitigate heavy metal contaminants.

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Section: Cadmium (Cd)mentioning

confidence: 99%

Trace Metal Contamination in Community Garden Soils across the United States

Malone,

Shakya

2024

Sustainability

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“…Carbonate and lime-based amendments are exploited for their alkaline character and are used to increase the pH of acid soils. The effective reduction of phytoavailability has been demonstrated for several metal(loid)s [45][46][47][48][49][50][51][52][53]. Aluminosilicates such as natural zeolites are efficient when employed alone for Cd and Pb [54,55] and in a mixture with organic amendments in the case of Cd and Pb as well as Zn [56,57].…”

Section: Introductionmentioning

confidence: 99%

Effects of Inorganic and Organic Amendments on the Predicted Bioavailability of As, Cd, Pb and Zn in Kitchen Garden Soils

Schnackenberg¹,

Bidar²,

Bert³

et al. 2021

AEER

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Moderately contaminated garden soils can benefit from gentle remediation options such as soil amendments, which improve soil functions and agronomic potentialities while decreasing environmental and human risk. This study aimed to analyze the effects of doses of various common soil amendments generally applied by gardeners on the predicted bioavailability (i.e., extractability) of metal(loid)s (i.e., As, Cd, Pb, and Zn) in contaminated kitchen garden soils. Fourteen different amendment mixes (i.e., a green waste compost with two degrees of maturity used alone and in combination with zeolite, three organic fertilizers, two calcareous amendments, two natural siliceous or alumino-silicate amendments, and one potting soil) were tested on three different garden soils with diverse sources of contamination and physico-chemical characteristics. Chemically extractable metal(loid)s were analyzed using 0.05 M EDTA extraction and 1 M NH4NO3 extraction. In one soil sample, potting soil showed significant potential to reduce the availability of As, as analyzed by both extractants. This amendment also effectively reduced the Pb extractability in the geogenic-contaminated soil, as did other high-organic matter amendments such as various application rates of composts. Zeolite and zeolite-compost mixes demonstrated success on various metal(loid)s and therefore could be a promising emerging amendment mix. Other efficient amendments include crushed horn, which effectively reduced available Zn in all soils, as well as available Pb. The application of bone meal similarly reduced the extractable As, Pb, and Zn in various soils. The two applications of limes were effective against Cd, As, Pb, and Zn in the different soils studied. This study provided evidence that it is possible to reduce the extractability and thus the environmental availability of the metal(loid)s applied with available and affordable amendments. The results depended on the physico-chemical soil parameters and metal(loid)s considered. There is no single solution, which implies that tests must be carried out before any implementation activities on the kitchen gardens.

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“…One method of achieving this in sludge-amended soils is to maintain a high soil pH as the proportion of`bioavailable' metal decreases with increasing pH (Berglund & Reidel 1983). Application of lime to sludge-amended soils has been shown to reduce crop Cd concentrations by about 20% and Zn concentrations by about 35% for each pH unit increase up to pH 7.0 (Preer et al 1995). Other management tools available to operators of sludge-amended sites are limited but include grain-blending, choice of crop and sludge disposal policy.…”

Section: Introductionmentioning

confidence: 99%

Modelling of Cd, Cu, Ni, Pb and Zn uptake, by winter wheat and forage maize, from a sewage disposal farm

R.L.*¹,

Young²,

Crout³

2003

Soil Use and Management

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A predictive model of metal concentrations in crops was developed to optimize soil liming and sludge application strategies at a dedicated sewage sludge disposal site. Predictions of metal concentrations in plant tissue were derived from measured values of soil metal concentration, humus content and soil pH. The plant and soil data used to parameterize the model were collected on site using quadrat sampling of mature crop and underlying topsoil. The uptake model was used to map predicted metal concentrations in wheat grain and forage maize based upon a database of soil characteristics (metal content, % humus and pH) measured as part of a routine geochemical survey of the site. The effect of a management strategy to modify uptake of Cd by wheat by changing soil pH was investigated. The effect of soil dust adhering to maize plants at harvest was also simulated to investigate the importance of this pathway for Cd transfer to animal feed such as silage.The model gave satisfactory predictions for uptake of Cd and Zn but less useful simulations for Pb, Cu and Ni. The results for Cd uptake showed a greater dependence on soil pH in the case of wheat in comparison to maize. It is suggested that, for the study site, liming to pH 7.0 will reduce Cd concentrations in wheat grain to within EC legal standards. However the Cd content of maize may still exceed these guidelines, with a relatively minor contribution from contamination with soil dust.

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Metals in urban gardens ‐ effect of lime and sludge

Cited by 9 publications

References 3 publications

Trace Metal Contamination in Community Garden Soils across the United States

Trace Metal Contamination in Community Garden Soils across the United States

Effects of Inorganic and Organic Amendments on the Predicted Bioavailability of As, Cd, Pb and Zn in Kitchen Garden Soils

Modelling of Cd, Cu, Ni, Pb and Zn uptake, by winter wheat and forage maize, from a sewage disposal farm

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