Archive | 2021
Environmental impact of tires used in marine construction
Abstract
Summary Scrap tires have been widely used around the world to construct artificial reefs to promote fisheries and to a lesser extent in coastal projects such as breakwaters. They are a popular construction material being readily available at no cost that are durable and have large void spaces. These latter features are a disadvantage in land disposal. The fact that underwater tire structures are successfully colonized by encrusting marine organisms and fish species has been taken as proof of their suitability. In 1998 an experimental scrap tire artificial reef was constructed in Poole Bay, southern UK to provide data on the environmental impact of the material. Colonization was monitored for comparison to that on concrete control modules deployed at the same time. Samples of the marine organisms growing on the reef have been analyzed for heavy metals and organic compounds. Results to date from this study showed no evidence for significant uptake by reef organisms of tire compounds and that there was little difference in the benthic community structure between the rubber rock modules and the concrete control units. Over two decades later this experimental tire reef is still flourishing. The Pevensey coast, southern UK is eroding, requiring routine engineering to maintain the beach. Use of compressed tire bales was proposed to reduce the requirement for offshore dredging. In 2002, 300 tire bales were installed within the beach. This pilot scheme was designed to assess the possible environmental impact of a large-scale installation the length of Pevensey Haven. The main concerns are (1) whether the filler will affect the hydrodynamics of the beach and therefore affect the groundwater table, and (2) whether potentially toxic leachates from the tire bales will have an adverse impact on the environment. Monitoring of dissolved zinc levels in the interstitial water for 6 years after deployment has refined models of the rate of zinc leaching from the tires showing diminishing release. In this chapter the scientific literature on marine tire leachates is reviewed to date. In recent years there has been a rapid increase in concern over the presence and impact of microplastics in the marine environment. The impact of tire dust from road runoff is contrasted with the lesser impact of whole tires.