Pathogens, environmental impact

Selective toxicity is also important in relation to the development of resistance or tolerance to pollutants from two distinct points of view. On the one hand, there is interest among scientists concerned with crop protection and disease control in mechanisms by which crop pests, vectors of disease, plant pathogens, and weeds develop resistance to pesticides. Understanding the mechanism should point to ways of overcoming resistance, for example, other compounds not affected by resistance mechanisms or synergists to inhibit enzymes that provide a resistance mechanism. On the other hand, the development of resistance can be a useful indication of the environmental impact of pollutants. 

More recently, a range of other quality and safety issues have been recognised by consumers and now influence poultry meat and egg buying patterns and behaviour. Most importantly this includes (i) the routine use of antibiotics as growth promoters and curative medicines and the potential for development of transferable antibiotic resistance, (ii) risk associated with enteric pathogen (e.g. Salmonella and Campylobacter) and toxin (e.g. dioxin) contaminants of poultry products, (iii) the environmental impact of poultry production and (iv) the sensory and nutritional quality of eggs and poultry meat (Menzi et al., 1997 Hamm et al., 2002 Rodenburg et al., 2004 Horsted et al., 2005). 

Soil and Environmental Analysis Physical Methods, Second Edition, Revised and Expanded, edited by Keith A. Smith and Chris E. Mullins The Rhizosphere Biochemistry and Organic Substances at the Soil-Plant Interface, Roberto Pinton, Zeno Varanini, and Paolo Nannipieri Woody Plants and Woody Plant Management Ecology, Safety, and Environmental Impact, Rodney W. Bovey Metals in the Environment Analysis by Biodiversity, M. N. V. Prasad Plant Pathogen Detection and Disease Diagnosis Second Edition, Revised and Expanded, P. Narayanasamy... 

For most of the drug substances the environmental impact is unknown, but for different types of antibiotics or antimicrobials a lot of concern is raised because of the development of bacterial resistance towards the drugs through different molecular mechanisms (Kruse and Sorum, 1994). This poses a threat to animals as well as humans, with the development of multiresistant, sometimes pathogenic, microbial strains (Midtvedt, 1998)... 

Wastewater comprises liquid waste discharged by households, industries and commercial establishments, and is typically collected through sewage pipes in municipal areas. Wastewater also contains chemicals and pathogens that can lead to serious negative impacts on the quality of the environment as well as human health if it is drained directly into major watershed without treatment [4,5]. The use of wastewater as a feedstock in the production of PHA has been proposed as a relevant approach in the shift from a petrochemical-based chemical industry towards a biobased one in order to decrease its manufacturing cost and environmental impact [6]. 

Environmental conditions also impact the extent of activity of allelopathic phenolics, with a number of abiotic and biotic stresses probably accentuating their action. Stress may result from pathogens, herbivory, herbicides,... 

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