Impact of Pollution on Animal Products pp 147-162
Contamination by Persistent Chemical Pesticides in Livestock Production Systems
The impact of persistent organic pesticides represents one of the major environmental problems as reported in several studies and reflected in some mandatory actions at the inter-governmental level. In particular, isomers of Hexachlorocyclohexane (HCH), like many others Organochlorine Pesticides (OCPs), are of human health and environmental concern due to their persistence in the biosphere. In industrialised countries, Lindane (the γ-isomer of HCH with insecticide effects) has been widely used in the past. As a consequence, large quantities of HCH isomers without insecticide effects (α-, β-, δ- and ε), discarded during the purification of Lindane, have been disposed for years into dumps around industrial sites. Nowadays, such uncontrolled disposal practices imply a great risk of environmental contamination, possibly threatening animals and humans by food chains transfer and bio-accumulation. In 2005, dairy cow farms in the Province of Rome (Italy) were threatened due to environmental contamination of the Sacco River by HCHs. As a case study, all components of the dairy cow production system undergoing agroenvironmental pollution crisis, were investigated with the aim to analyze the main critical points. Five dairy farms were involved in the research. Data regarding the contamination by HCHs of soils, forages, bovine milk and blood serum are reported. Soil and forage samples (mainly maize, alfalfa and ryegrass) were taken in different places near the Sacco River, on the basis on irrigation practiced and flooding conditions. All samples were analyzed by Gas Cromatography using an Electron Capture Detector. Soil contamination by HCHs was found higher nearby than away the river (p < 0.01) with a great incidence of outflow risk (p < 0.01), while no differences were observed on the basis of irrigation practices. In alfalfa samples higher concentration of HCHs than in ryegrass were detected, with a greater plant/soil apparent partition factor. Differences in milk contamination by β-HCH among dairy farms (p < 0.01) and sampling time were found (p < 0.05). In many cases, the β-HCH content of milk resulted above the EU limit (0.003 mgβ-HCH/kg), posing serious hazard for human consumption due to chronic toxicity of that isomer. Differences in milk β-HCH concentration were found related to lactating phase and parity. A linear regression between blood serum and milk β-HCH concentration was observed (r2 = 0.919, p < 0.05). Furthermore, β-HCH as a trace was detected in blood sera when milk levels fell below the analytical limits, indicating the usefulness of blood serum HCH content as an early indicator of animal exposure. Results obtained from the case study highlighted the needing for further researches at wider level, due to the strong impact of persistent organic pesticides on rural environment and human food chain.
KeywordsPOPs HCHs dairy farming agro-environmental pollution
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