Sweeter grass due to lead contamination?

Do you ever wonder why sheep and livestock graze around roads and stick their heads through fences just to reach out for grass? Or why do children ingest soils and dusts in playgrounds and around gardens?

Fuge (2013) states that there seems to be a tendency of a larger number for sheep graze near roads and historical lead mines as elevated lead concentrations may cause the sweeter taste of the grass. Furthermore, Mielke (1999) claims that toddlers may be tempted to ingest leaded paint at home and gardens due to similar reasons.

The sweet properties of this element have been recognised since as far back asthe Romans as lead was added to wine and many other dishes to improve its taste (Herbert and Needleman, 1999). Furthermore, utensils were often made of lead. It has been estimated that their daily intake varied between 35 mg/day to ~ 250 mg/day, compared to modern intakes of 0.3 mg/day recorded in the US in the 1980’s (National Academy of Sciences 1980). Its poisonous and toxic nature however, has been recognised as early as 2000 BC (Herbert and Needleman, 1999). The Greek philosopher Nikander described symptoms such as colic and anaemia due to lead poisoning.

Lead toxicity and its implications to life on Earth became a major concern in the last three decades as lead occurs in appreciable amounts in all rocks and soils (DeTreville, 1964). Many studies show that it can have detrimental effects-mainly to the central nervous system (CSN); it can also cause a range of chronic diseases and health effects and lead to lowering of the IQ, myocardial infarction and stroke mortality (Alloway et al., 2005) derived from the consumption of food and drinks: via plants, animals and drinking polluted water but also during respiration (HSMO, 1974). However, lead was added to petrol to improve engine performance despite all its known toxic and harmful qualities.

Mielke and Reagan (1998) concluded that leaded petrol, industrial sources and lead-based paints deterioration seem to be the major sources of contamination in soils. Thornton and Abrahams (1983) claim that 4000 km2 of agricultural land have been affected by contamination caused by historical mining and smelting processes in England and Wales. Urban centres reflect many anthropogenic sources: motor vehicle exhaust at a very high rate, ore processing, industrial activities, coal combustion, and agricultural practices at a relatively high rate due to the rapid economic and population growth. The high lead values coincide with densely populated urban centres such as Birmingham, Newcastle, and London, wide areas around Liverpool, Manchester and Swansea. Although lead has been banned since 1998 in the UK and since 1970s in the USA, it is still considered as a great thread as lead is an immobile element and persists in the environment over a large period of time. Recently, a relationship between crime rate and lead bone poisoning has been found (Needleman, 2004). Mielke et al. (2007) has shown that in New Orleans 93.5% children are at risk caused from lead-based paint deterioration and leaded petrol ant its accumulation in soils. Does the same thread occur in the UK?

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Denitsa Tarnovska

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