Pollution and bio-diversity

Pollution can be defined in many ways: as that arising from the built environment ( for example sewage and waste), pollution caused by the manufacturing of materials and products, pollution and hazards from the handling and use of materials or from the site itself and other construction, and operationally related activities (Dixon, 2010). The study by Kukadia et al. (2003) acknowledges the British Research Establishment’s (BRE) definition of pollution as the introduction of contaminants

53

into the natural environment, damaging it. It states that, in line with the construction industry, it could take the form of chemical substances, such as air, particles, noise, heat, vibration and vaporous discharges.

Pollution has been defined from a construction perspective as ‘particles, noise, vibration and vaporous discharges’ (Kukadia et al., 2003; Pitt et al., 2009). According to BIMhow (2013), the construction sector contributes to 23% of air pollution, and 40% of drinking water pollution. Raw materials extraction and construction activities also contribute to the accumulation of pollutants in the atmosphere, mostly in the processing of materials for construction. The design and construction phases involve the specification of materials, and the use of plant, processes and techniques. Pollution impacts also include large disturbances to the existing environment, whether on the greenfield or previously developed sites. Each of these activities poses a risk of introducing pollutants into the atmosphere, which can affect workers on site, the neighbourhood, or the quality of the local ground, water, and air. Similar impacts can occur during the operational phase of development. Such disturbances can also upset the equilibrium between the land, water and air and introduce the risk of pollution.

According to Holton et al. (2008), the UK’s construction is responsible for 40% of atmospheric emissions, 20% of water effluents, and 13% of other releases. Dust and other emissions include some toxic substances such as nitrogen and sulphur oxides. They are released during the production and transportation of materials as well as from site activities and have caused a serious threat to the natural environment (Rohracher, 2001). In its reports, the HoC (2006) affirms that global greenhouse gas emissions have increased more than four-fold in the last half of the twentieth century. Other harmful materials, such as chlorofluorocarbons (CFCs), are used for insulation, air conditioning, refrigeration plants and fire-fighting systems and have severely depleted the ozone layer (Clough, 1994; Langford et al., 1999). The need to identify the risks associated with pollution in the environment and the steps taken to minimise potential pollution has been emphasised (OGC, 2005). Zolfagharian et al. (2012), BIMhow (2013), and Sustainablebuild (2017) summarise the three significant pollutions and how they are generated during construction activities; these include:

54

2.5.3.1 Air pollution

Construction activities that contribute to air pollution include land clearing, the operation of diesel engines, demolition, burning and working with toxic materials. All construction sites generate high levels of dust typically from concrete, cement, wood, stone, and silica. Construction dust is categorised as a particulate matter less than 10 microns in diameter (PM10), which cannot usually be seen without a microscope. There is also the issue of transportation; materials that are not produced locally are transported often across the country and from overseas. The mode of shipment of these materials has a considerable impact on air quality.

2.5.3.2 Noise pollution

Construction sites produce a lot of noise, mainly from vehicles, heavy equipment and machinery, but also from people shouting and radios turned up too loud during construction. Excessive noise is not only annoying and distracting but can lead to hearing loss, high blood pressure, sleep disturbance, and extreme stress. Research has shown that high noise levels disturb the natural cycles of animals and reduces their suitable habitat.

2.5.3.3 Water pollution

Sources of water pollution on building sites include diesel and oil, paint, solvents, other harmful chemicals, and construction debris and dirt. When land is cleared, it causes soil erosion that leads to silt-bearing run-off and sediment pollution. Silt and soil that runs into natural waterways turn them turbid, which restricts sunlight filtration and destroys aquatic life. Surface water run-offs also carry other pollutants from the site, such as diesel and oil, toxic chemicals, and building materials such as cement. When these substances enter waterways, they poison water life and any animal that drinks from them. Pollutants on construction sites can also soak into the groundwater, a source of water for human consumption. Once contaminated, groundwater is much more difficult to treat than surface water. Table 2.2 highlights the estimate of global pollution generated by buildings.

55

Table 2.2 Estimate of global pollution that can be attributed to buildings (Brown and Bardi, 2001)

Pollution %

Air quality (cities) 23 Climate change gases 50 Drinking water pollution 40

Landfill waste 50

Ozone depletion 50

Pollutants are usually released into the biodiversity causing severe land and water contamination, frequently due to negligence on construction project sites. Consequently, spillages are washed into underground aquatic systems and reservoirs (Huberman and Pearlmutter, 2008). The accumulated amount of adverse environmental impacts such as waste, noise, dust and hazardous emissions still occur during the construction process, which causes severe damage to humans and ecosystems (UNEP, 2003; Zolfagharian et al., 2012). With the rise in the number of constructions of new buildings, the ecosystems/biodiversity impact of construction has become an important issue.

Langford et al. (1999) argue that around one-third of the world's land is being degraded and pollutants are depleting environmental quality, interfering with the environment's capacity to provide a naturally balanced ecosystem. Thus, the need to identify the risks associated with pollution in the environment and the steps taken to minimise potential pollution has been suggested (Pitt et al., 2009). Having known the negative impacts of pollution, necessary steps should be taken by the industry to protect biodiversity (ecosystem, genetic, and cultural) through good design and landscaping (OGC, 2005). In addition, if the construction industry continues to overuse natural resources without mitigating measures, a limit on economic growth will eventually emerge. Hence, the destruction of the environment will undoubtedly have an adverse effect on the construction industry.

56