Polycyclic Aromatic Hydrocarbons: potential sources from the vineyard and analysis in wine

Alessandri, Anne (2016-12)

Thesis (MScAgric)--Stellenbosch University, 2016.

Thesis

ENGLISH ABSTRACT: The South African wine industry plays an important role in the economy, contributing R36.1 billion gross domestic product (GDP) to the regional economy and employing 300 000 people both directly and indirectly in 2013. In order to build on this, the local industry continues to align itself to international trends and expectations. At the same time, polycyclic aromatic hydrocarbons (PAHs) are under continued scrutiny for their impact on the environment and health, due to their mutagenic and carcinogenic properties. There has been some concern that grapes grown in South African vineyards may be exposed to various sources of PAH contamination. These sources of contamination include the usage of creosote posts in vineyards, bush fires and vehicle emissions, as well as the use of charred barrels in the cellar. The aim of this study was to determine if the exposure to PAHs resulted in the presence of PAHs in wine, and at which levels they may be present in wine. Chapter 3 compared the use of the Ultra high-pressure liquid chromatography coupled with Fluorescence detection (UPLC-FLD) and the High-pressure liquid chromatography coupled with Fluorescence detection (HPLC-FLD) system for the analysis of PAHs in wine. Wine samples were extracted using the liquid-liquid extraction method developed by Panzeri (2013). It was found that both methods were suitable for low level PAH analysis, with the UPLC-FLD detector being faster. In chapter 4, a selection of South African and international wines were analysed to determine the levels of PAHs found in the wines. The wines analysed had been randomly selected, from different regions, cultivars and vintages. Some wines had been made from grapes grown in vineyards using creosote posts for trellising and some were bush vines with no posts used at all. Some of the wines had been fermented or aged in oak barrels, while some had no wood treatment. The result of the analysis was that the majority of the wines selected had very low levels of PAHs. The levels were not high when compared to the legal limits set by the European Union of 1 ppm B[a]P for all dietary food (European Directive 2006/125/EC). The quantities of PAHs found in the wine samples were all below 2 ppb, which is the guideline set by AFFSA, the French Agency for Food, Environmental and Occupational Health & Safety (AFFSA, 2006). There were no differences between the PAH levels in South African and international wines. Some wines analysed had levels of PAHs higher than the legal limit allowed in water of 0.01 μg/L for B[a]P and 0.1 μg/L for the sum of B[b]F, B[k]F, B[ghi]P and Ind[1, 2, 3-cd]P (European Directive 2006/125/EC). This was potentially due to an accumulation of contamination from various sources – creosote, vehicle emissions, exposure to smoke from bush fires and extended barrel aging. By eliminating creosote posts in the vineyard, avoiding bush fires just before harvest, as well as monitoring the use of charred oak barrels, the PAH levels should be reduced to levels below the legal limits in water. Further work could include looking at vineyards with high levels of PAHs in the soils and investigate how to reduce or remove the PAHs. The degradation of PAHs in wine over time could also be monitored.

AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse wynbedryf speel ’n belangrike rol in die ekonomie en het in 2013 ’n bydrae van R36.1 biljoen bruto binnelandse produk (BBP) aan die streeksekonomie gemaak en tot 300 000 mense direk en indirek in diens gehad. Om hierop te kan bou, belyn die plaaslike bedryf homself voortdurend met internasionale tendense en verwagtinge. Terselfdertyd is polisikliese aromatiese koolwaterstowwe (PAK’e; polycyclic aromatic hydrocarbons (PAHs)) onder voortgesette noukeurige ondersoek vir hulle impak op die omgewing en op gesondheid as gevolg van hulle mutageniese en karsinogeniese eienskappe. Daar is ’n mate van kommer dat druiwe wat in Suid-Afrikaanse wingerde groei, aan verskillende bronne van PAK besmetting blootgestel word. Hierdie bronne van besmetting sluit in die gebruik van teerpale in wingerde, veldbrande en uitlaatgasse van voertuie, sowel as die gebruik van vate in die kelder. Die doel van hierdie studie was om te bepaal of blootstelling aan PAK’e lei tot die teenwoordigheid van PAK’e in wyn, en teen watter vlakke hulle moontlik in die wyn teenwoordig is. Hoofstuk 3 vergelyk die gebruik van ’n stelsel van ultra hoëdrukvloeistofchromatografie tesame met fluoressensie aftasting (UPLC-FLD) en hoëdrukvloeistofchromatografie tesame met fluoressensie aftasting (HPLC-FLD) vir die analise van PAK’e in wyn. Wynmonsters is geëkstraheer met gebruik van die vloeistof-vloeistof ekstraksiemetode wat deur Panzeri (2013) ontwikkel is. Daar is gevind dat beide metodes gepas was vir die analise van lae-vlak PAK, met die UPLC-FLD aanwyser wat vinniger was. In hoofstuk 4 word ’n verskeidenheid Suid-Afrikaanse en internasionale wyne geanaliseer om die PAK-vlakke in die wyne te bepaal. Die wyne wat geanaliseer is, is lukraak gekies vanuit verskille streke, kultivars en oesjare. Sommige wyne is gemaak met druiwe vanuit wingerde wat teerpale gebruik as opleistelsel en ander was bosstokke waarvoor geen pale gebruik is nie. Sommige wyne is in eikehoutvate gegis of verouder, terwyl ander geen houtbehandeling ondergaan het nie. Die uitslag van die analises was dat die meerderheid wyne baie lae vlakke PAK’e bevat het. Die vlakke was nie hoog in vergelyking met die perke wat deur die Europese Unie bepaal is nie, naamlik 1 dpm B[a]P vir alle voedsel (European Directive 2006/125/EC). Die hoeveelhede PAK’e wat in die wynmonsters gevind is, was almal benede 2 dpb, wat die riglyn is van die AFFSA, die Franse Agentskap vir Kos-, Omgewings- en Beroepsgesondheid en Veiligheid (AFFSA, 2006). Daar was geen verskille in die PAK-vlakke tussen die Suid-Afrikaanse en internasionale wyne nie. Sommige van die geanaliseerde wyne het PAK-vlakke gehad wat hoër was as die wettige perk wat in water toegelaat word, van 0.01 μg/L vir B[a]P en 0.1 μg/L vir die som van B[b]F, B[k]F, B[ghi]P en Ind[1, 2, 3-cd]P (European Directive 2006/125/EC). Dit is potensieel as gevolg van die ophoping van besmetting vanaf verskillende bronne: teer, uitlaatgasse van voertuie, blootstelling aan rook vanaf veldbrande en verlengde vatveroudering. Deur teerpale uit wingerde te verwyder, veldbrande kort voor oes te vermy, sowel as die gebruik van eikehoutvate te monitor, sal PAK-vlakke moontlik verlaag word tot vlakke benede die wettige perk in water. Verdere werk sou die bestudering van wingerde met hoë vlakke van PAK’e in die grond kon insluit, tesame met ondersoeke oor hoe die PAK’e verminder of verwyder kan word. Die afbreking van PAK’e in wyn oor tyd kan ook gemonitor word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100428
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