The effect of a creosote stockyard on the environment, vines and wines

[摘要] ENGLISH ABSTRACT: The quality of wine is largely dependent on environmental conditions and recent studieshave therefore focused on agricultural practices in terms of water, soil and biodiversityconservation. The industry aims to create sustainable practice and to protect the naturalresources available. Sources of potential grape contamination include: vehicle pollution,pesticides, bushfires and wood preservatives used for trellising systems. The latter havecome to the attention of the South African wine industry (e.g. creosote and CopperChromium Arsenate (CCA) products) as they may have consequences for the environmentand wine quality. Creosote is a known pollutant of soil and ground water and the volatilefraction has been monitored in air. Plants may also accumulate polycyclic aromatichydrocarbons (PAHs), which constitute up to 85% of the mass of creosote, and of whichsome have been proven carcinogenic. Because of the health risks associated with it,creosote has therefore been restricted for use in most applications in Europe, and also inthe United States, Canada and Australia.This study focussed on the sensorial and chemical analyses of environmental and winesamples taken from the area around the creosote stockyard to determine accumulation ofcreosote-derived compounds. Environmental samples were collected and analysed atdifferent distances from the affected area, over two vintages. Wines were made fromgrapes grown in vineyard blocks adjacent to the stockyard, to determine the effect ofdistance and skin contact during alcoholic fermentation treatments on wine taint. Asensory panel was trained for descriptive analysis to determine the intensity of the taint.Analytical methods were developed for the analysis of volatile organic compounds (VOCs)by gas chromatography mass spectrometry (GC-MS) and polycyclic aromatic hydrocarbonsby high performance liquid chromatography with diode array detection (HPLC-DAD).The sensory results obtained showed white and rosé wines were perceived as clean,whilst the red wines were associated with burnt rubber/tar taint. The perceived taintdecreased as distance from the stockyard increased. Wines made from the CabernetSauvignon blocks adjacent to the stockyard also showed an increase of taint with theincrease of skin contact. Chemical data obtained showed that the taint consisted of acomplex mixture of compounds, each with its own pattern of retention within the vineyardand wine. Only m-cresol was found above odour threshold, and only in red wines. Thesynergistic effect of some compounds may lead to an increase in the perceived taint.Berries and leaves had higher concentrations of volatile compounds than wines. Leafcontamination varied and followed the general trend in literature where the plants with highlipid content and exposed leaf area were the most contaminated. There may be other compounds present in creosote emissions, aside from those investigated here, withsensory attributes related to the taint found in wines. These compounds are styrene,indene, benzene, toluene, isoquinoline and quinoline and should be included in furtherinvestigations.From the PAH analysis of environmental samples and wines, it is evident that thesamples closest to the stockyard were affected the most. The contamination varied withthe depth of the soil: some of the heavier compounds were found in the samples taken fromthe deeper levels, whilst nearly all other target compounds were present in the top layer ofsoil. The concentrations found in the environmental samples were lower than reported inliterature. Wines had few PAHs present, but at much higher concentrations than is allowedby EU legislation.From this study it is evident that the stockyard had negative effects on the surroundingenvironment in terms of sensory and chemical contamination. Recommendations includearea rehabilitation by means of bioremediation to protect resources and ensure sustainableand safe production of crops. Industrial emissions should also be regulated and restrictedin agricultural areas. Furthermore the use of creosote should be revised, and prohibited foragricultural use.

[发布机构] Stellenbosch University