Search

found 34 results

Images for metal; more images...

Research Papers, Lincoln University

Numerous studies have shown that urban soils can contain elevated concentrations of heavy metals (HMs). Christchurch, New Zealand, is a relatively young city (150 years old) with a population of 390,000. Most soils in Christchurch are sub-urban, with food production in residential gardens a popular activity. Earthquakes in 2010 and 2011 have resulted in the re-zoning of 630 ha of Christchurch, with suggestions that some of this land could be used for community gardens. We aimed to determine the HM concentrations in a selection of suburban gardens in Christchurch as well as in soils identified as being at risk of HM contamination due to hazardous former land uses or nearby activities. Heavy metal concentrations in suburban Christchurch garden soils were higher than normal background soil concentrations. Some 46% of the urban garden samples had Pb concentrations higher than the residential land use national standard of 210 mg kg⁻¹, with the most contaminated soil containing 2615 mg kg⁻¹ Pb. Concentrations of As and Zn exceeded the residential land use national standards (20 mg kg⁻¹ As and 400 mg kg⁻¹ Zn) in 20% of the soils. Older neighbourhoods had significantly higher soil HM concentrations than younger neighbourhoods. Neighbourhoods developed pre-1950s had a mean Pb concentration of 282 mg kg⁻¹ in their garden soils. Soil HM concentrations should be key criteria when determining the future land use of former residential areas that have been demolished because of the earthquakes in 2010 and 2011. Redeveloping these areas as parklands or forests would result in less human HM exposure than agriculture or community gardens where food is produced and bare soil is exposed.

Images, UC QuakeStudies

A photograph of a piece of plywood sitting on top of a pile of bricks from the Carlton Hotel. USAR codes have been spray-painted on the wood. In the foreground, metal fencing, cordon tape and a road cone have been used to cordon off the building.

Images, UC QuakeStudies

A photograph of the earthquake damage to Knox Church on the corner of Bealey Avenue and Victoria Street. The walls of the gables have crumbled, and the bricks have fallen onto the footpath. Road cones, metal fences, and cordon tape have been placed around the building as a cordon.

Images, UC QuakeStudies

An excavator bunching up scrap metal as part of efforts to clear the site of the demolished Hillary and Marshall Limited building on Manchester Street. A pile of scrapped wooden components can be seen at the back of the site, and a pile of masonry is visible in the foreground.

Images, UC QuakeStudies

Damage to the front gable of the Durham Street Methodist Church. Masonry has fallen from the top of the gable, and the resulting gap has been weather proofed with plywood, tarpaulins and metal tiles. The steel bracing propping the whole front wall can be seen at the bottom of the photograph.