Journal of Environmental Science and Health, Part B Pesticides, Food Contaminants, and Agricultural Wastes
ISSN: 0360-1234 (Print) 1532-4109 (Online) Journal homepage: http://www.tandfonline.com/loi/lesb20
Presence of PAHs in milk of industrial farms from Tizayuca, Hidalgo, Mexico Rey Gutiérrez, Salvador Vega, Rutilio Ortiz, José Jesús Pérez & Beatriz Schettino To cite this article: Rey Gutiérrez, Salvador Vega, Rutilio Ortiz, José Jesús Pérez & Beatriz Schettino (2015) Presence of PAHs in milk of industrial farms from Tizayuca, Hidalgo, Mexico, Journal of Environmental Science and Health, Part B, 50:5, 317-321, DOI: 10.1080/03601234.2015.1000166 To link to this article: http://dx.doi.org/10.1080/03601234.2015.1000166
Published online: 31 Mar 2015.
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Date: 10 November 2015, At: 14:09
Journal of Environmental Science and Health, Part B (2015) 50, 317–321 Copyright © Taylor & Francis Group, LLC ISSN: 0360-1234 (Print); 1532-4109 (Online) DOI: 10.1080/03601234.2015.1000166
Presence of PAHs in milk of industrial farms from Tizayuca, Hidalgo, Mexico JESUS PEREZ REY GUTIERREZ, SALVADOR VEGA, RUTILIO ORTIZ, JOSE and BEATRIZ SCHETTINO
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Instrumental Analysis Laboratory, Animal and Agricultural Production Department, Autonomous Metropolitan University Xochimilco Campus, Coyoacan, M exico
The objective of this study was to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) in cow’s milk from industrial farms that are located near an industrial park in Hidalgo, Mexico. It was found that the concentrations of PAHs in the raw milk of cattle from industrial farms have increased in recent years. Composite samples were collected between 2008 and 2010 and analysis carried out according to 8100 EPA procedures and analyzed by gas chromatography with FID detection. The results show that combustion PAHs were mostly Ace, Acy, and Fla (0.25, 0.32, and 0.22 mg g¡1, respectively). Diagnostic ratios were used to show that the probable sources were grass and fuel combustion. The sum of concentrations of 16 individual PAHs did not breach permissible levels in milk (25 mg g¡1 according to the United States EPA), indicating a limited health risk to animals and humans in the study area. The industrial park has adequate pollutant emission regulations. Keywords: Contamination, milk production, industrial farm, Mexico.
Introduction Polycyclic aromatic hydrocarbons (PAHs) are products of the incomplete combustion or pyrolysis process of organic material; other sources are incineration, fossil fuel combustion and industrial activities.[1] In general, the contribution from human activities is much greater than from natural sources such as volcanic eruptions, diagenesis and natural forest fires. PAHs were included as priority pollutant lists of the Agency of Toxic Substances and Disease Register (ATSDR), the International Agency for Research on Cancer (IARC), the Environmental Protection Agency (EPA), and Stockholm Convention due to their mutagenic and carcinogenic properties.[2] EPA has listed 16 PAHs of environmental interest. Once PAHs are released into the atmosphere, they can be transported away from their emission sources over long distances and/or deposited to the terrestrial and aquatic environment through dry and wet deposition. In fact, uptake of gaseous chemicals by plants is one of the major Address correspondence to Salvador Vega, Instrumental Analysis Laboratory, Animal and Agricultural Production Department, Autonomous Metropolitan University Xochimilco Campus, Delegaci on Coyoac an, Mexico D.F. 04960, Mexico; E-mail:
[email protected] Received September 5, 2014. Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lesb.
pathways of PAHs as well as many other semi-volatile contaminants into the agricultural food chain. PAHs then enter the human food chain directly for example through the consumption of grains and vegetables, or indirectly through animal produce (meat and milk). The intake of contaminated food and fodder by animals is the main source of entry of organic pollutants into the animal body, which ultimately results in the contamination of milk, meat, etc. consumed by human beings.[3] Human exposure to PAHs is estimated to be 88 to 98% connected with food.[4] PAHs can contaminate food indirectly (from air or water) and directly, e.g. during smoking. The presence of contaminants in milk is of particular concern as it can be considered as a nearly complete food since it is a good source of protein, fat, and major minerals. Also, milk is one of the main constituents of the daily diet, especially for vulnerable groups such infants, school age children and old.[5] PAHs are considered as possible carcinogens, for example benzo(a)anthracene in animals and benzo(a) pyrene in humans, and these PAHs have been shown to cause alteration in cellular division and growth in bacteria and plants, and to inhibit some metabolic mechanisms (depending on exposure doses). Certain organic environmental chemicals, including pesticides termed as endocrine disruptors, are known to elicit their adverse effects by mimicking or antagonizing natural hormones in the body and it has been postulated that their longterm, low-dose exposure is increasingly linked to
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318 human health effects such as immune suppression, hormone disruption, diminished intelligence, reproductive abnormalities, and cancer.[6] In 2001, the Mexican government signed up to the Stockholm Convention with the intention of reducing and prohibiting the use of some organic pollutants, for example by regulating their emissions, use, and sale in strategic activities such agriculture and industry.[7] A long-term monitoring programme by government or academic institutions is necessary to verify that these regulations are having the desired effect on environmental concentrations. Some investigations have shown that natural food has high levels of pollutants near industrial and urban locations, and these can cause contamination of food and problems for public health. In this paper, we report the concentrations of PAHs in cow’s milk from industrial farms that are located near an industrial park in Hidalgo, Mexico.
Materials and methods Sampling Bovine milk samples (60) were collected from industrial farms in the southern part of Hidalgo. This region is 2000 m above sea level and the climate is temperate and semi-dry, with rains from June to September. Samples were taken fresh in the morning in glass bottles, kept in ice in a cool box during transport, and stored in a refrigerator in the laboratory before analysis. Sampling was carried out monthly from January 2008 to December 2010 with representative samples taken from random farms except during holiday times in August and September. The analysis was performed within 24 h of collection of the samples.
Analytical procedures A 250 mL aliquot milk sample was transferred to a suitable container and milk fat was obtained by extraction with detergent solution in a warm water bath.[8] 50 mg of fat was weighed and dissolved in hexane (HPLC grade) and the samples cleaned by passing through a chromatographic column. Chromatographic columns were prepared with silica gel and aluminum oxide deactivated with deionized water (5%) and topped with anhydrous sodium sulfate. The samples were passed through the columns then the PAHs eluted with a mixture of hexanedichloromethane (9:1 and 1:1 v/v). The organic extract was concentrated in a rotary evaporator to 1 mL and transferred to a vial for gas chromatographic analysis according to EPA method 8100.[9] The concentrations and profiles of PAHs were analyzed using a Perkin Elmer AutoSystem gas chromatograph (Column HP-5, 30 m, 0.35 mm ID, 0.25 mm film thickness, Perkin Elmer, Waltham, MA, USA). The oven
Guti errez et al. temperature was initially set at 90 C and held for 0 min then ramped at 8 C min¡1 to 180 C (1 min), then ramped at 5 C min¡1 to 245 C (0 min), and ramped at 2 C min¡1 to a final temperature of 300 C (0 min). Detector and injector temperature were 320 C. The carrier gas was high purity helium (99.99%). A sample of 1 mL was injected in splitless mode. Identification of PAHs was based on matching their retention time with a mixture of standards (Chem Service, West Chester, PA, USA). The 16 PAHs were naphthalene-Nap (Bicyclo[4.4.0]deca-1,3,5,7,9-pentene), acenaphthylene-Acy (acenaphthylene), acenaphthene-Ace (1,2Dihydroacenaphthylene), fluorene-Flu (9H-Fluorene), phenanthrene-Phe (Phenanthrene), anthracene-Ant (Anthracene), fluoranthene-Fla (Fluoranthene), pyrenePyr (Pyrene), benzo(a)anthracene-BaA (benz[a]anthracene), chrysene-Cry (Chrysene), benzo(b)fluorantheneBbF (benzo[b]fluoranthene), benzo(k)fluoranthene BkF (benzo[k]fluoranthene), benzo(a)pyrene (benzo[a]pyrene), indeno(1,2,3-cd)pyrene-Ind (indeno[1,2,3-cd]pyrene), dibenzo(ah)anthracene-DaA (dibenz[a,h]nthracene), and benzo(ghi)perylene-Bghi (benzo[ghi]erylene). Quality control was made by analysis of routine blanks, spiked recovery determination, duplicates, and comparison of standards. Solvent blanks were run with each sample batch. All solvents and others materials contacting samples were clean, as confirmed using blanks. Spiked recovery tests were performed periodically during analyses. All of these showed acceptable recoveries between 50 and 95% for the aromatic compounds and limits of detection were 0.01 and 0.10 mg g¡1 (Table 1). Comparison of chromatograms of fortified and unfortified blanks provided further evidence of the quality of method. The specificity of the method was checked daily through comparison of retention times. Further, the middle standard of the calibration curve was injected daily to evaluate the performance of the system. Although several of the blanks showed a few aromatic compounds at low concentrations, values were close to limits of detection so the areas of the samples were corrected by subtraction of the appropriate contaminant area, adjusted for recovery values. The variations of limits of detection in standards were 1.0 to 10.5% for 3 years of analysis. Quantification of individual PAHs was made by an external standard method.
Results and discussion Distribution of PAHs It is important to study PAHs in food as this is a route of exposure of these organic contaminants to domestic animals and humans. The main pathways of contamination are inhalation, skin contact, and ingestion.[10] According to Ounnas et al.,[11] the presence of PAHs in cow’s milk
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Presence of PAHs in milk of industrial farms from Tizayuca, Hidalgo, Mexico Table 1. Parameters for polycyclic aromatic hydrocarbons for analysis of cow’s milk.
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Compounds
Average Limit of Detection (mg g¡1)
% Recovery in Total Process (n D 7)
Standard Deviation
0.10 0.11 0.09 0.01 0.01 0.05 0.06 0.01 0.06 0.01 0.03 0.01 0.01 0.01 0.01 0.02
66 78 90 88 95 79 89 87 89 91 75 88 75 80 89 85
11.3 19.5 16.2 12.3 11.7 10.9 14.2 13.5 13.1 12.7 14.1 16.7 14.7 16.1 14.6 15.9
Napthalene Acenapthylene Acenaphtene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzo(a)anthracene Chrysene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(a)pyrene Indeno(1,2,3-cd)pyrene Dibenzo(ah)anthracene Benzo(ghi)perylene
occurred mainly after ingestion of soil when livestock grazed in fields, but our results shows contamination via food (pasture and prepared food) as the livestock were confined indoors. In general, the main compounds detected in this study were: Ace, BkF, Acy, BaA, Fla, Flu and Phe (2008); Ant, Fla, Ace-Pyr, Acy-BaA-BaP and Cry (2009) and Acy, Ace, Fla and Ant (2010). Ace, Acy, and Fla were consistently present. A high variability of concentrations was probably due to differences between the facilities in the industrial park (Table 2). These PAHs are similar to those described by Grova et al.[12] where Acy Ace, Flu, Ant, Fla, Pyr, and BaA were found to be present in the production units near Table 2. Mean concentrations of PAHs (mg g¡1) in milk samples from industrial farms from Tizayuca, Hidalgo. Compounds Nap (2) Acy (2) Ace (2) Flu (2) Phe (3) Ant (3) Fla (3) Pyr (4) BaA (4) Cry (4) BbF (4) BkF (4) BaP (5) Ind (5) DaA (5) Bghi (6) Total
2008
2009
2010
Nd 0.24 § 0.46 0.49 § 0.57 0.18 § 0.26 0.12 § 0.22 0.07 § 0.09 0.20 § 0.11 0.01 § 0.01 0.21 § 0.15 0.15 § 0.17 0.03 § 0.08 0.27 § 0.56 0.02 § 0.04 0.02 § 0.02 0.01 § 0.01 0.04 § 0.08 2.06 § 2.83
Nd 0.16 § 0.15 0.17 § 0.16 0.02 § 0.04 0.04 § 0.06 0.27 § 0.41 0.25 § 0.22 0.17 § 0.27 0.16 § 0.17 0.15 § 0.14 0.08 § 0.13 0.01 § 0.01 0.16 § 0.36 Nd 0.01 § 0.02 Nd 1.65 § 2.14
Nd 0.36 § 0.38 0.31 § 0.24 Nd 0.03 § 0.06 0.16 § 0.32 0.21 § 0.11 0.01 § 0.01 0.08 § 0.06 0.01 § 0.01 Nd 0.04 § 0.04 0.01 § 0.03 Nd 0.02 § 0.02 Nd 1.24 § 1.28
Note: Nd Not detected and * number of aromatic rings.
to emission sources of pollutants (cement, iron and steel industry). Chung et al.[13] and Braga et al.[14] found high concentrations of Nap, Acy, Flu y Phe originating from automobiles. The PAH BaP has been used as a reference parameter for toxicity to human health in many toxicology studies where it is described as a carcinogen in air, water, and food, although mainly in smoked food. We defined two seasons to examine the distribution of PAHs (Fig. 1). It can be seen that compounds with three and four aromatic rings were dominant throughout the sampling, although particularly in the wet season. Naphthalene was not found in the samples, probably due to degradation or volatilization during handling in the field and laboratory. In the dry season, the distribution of aromatic compounds was: 10.8% two rings, 38.6 % three rings, 37.3% four rings, 13.3% five rings, and 0% six rings (2008); 28% two rings, 26.8% three rings, 24.4% four rings, 14.6% five rings, and 6.1% six rings (2009); and finally 24.4% two rings, 26.8% three rings, 25.6% four rings, 19.5% five rings, and 3.7% six rings (2010). There was an increased level of low to medium molecular weight compounds (three and
Fig. 1. Percentage of PAHs (aromatic rings) in milk samples from industrial farms of Tizayuca, Hidalgo.
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320 four aromatic rings) in the wet season where increased wet deposition of pollutants from the atmosphere occurs in combination with agricultural and industrial activities (fuels and debris burn). In the dry season, strong winds commonly occur and facilitate the spread of pollutants. According to Cheng et al.,[15] the presence of five and six aromatic rings are indicative of high temperature combustion, conditions found in the steel, glass, and the petrochemical industry. Industrial activities in the area include production of steel, and some chemical industry (both of which involve high temperature conditions), as well as other industries such as textile, beverage, and food production. Figure 2 shows the distribution of individual PAHs and it can be seen that lower and intermediate molecular weight PAHs were present throughout the sampling. In general, in 2008, high levels of low and intermediate weight PAHs (Acy, Ace, Flu, Fla, BaA, Cry and BkF) were seen, while in 2009 Ant, Fla, Pyr, and BaP were present at greater concentrations than other PAHs. Finally, in 2010, the lower molecular weight PAHs that were present in high concentrations were Acy and Ace. The concentrations of BaP did not breach the permissible level of 1 mg g¡1 fat basis. The maximum concentration of this diagnostic compound for pollution was only 0.2 mg g¡1. Germany has a limit of 5 mg kg¡1 for heavy PAHs and 25 mg kg¡1 for the sum of all the16 PAHs highlighted by the US Environmental Protection Agency (EPA) in oil and fats. Canadian legislation has a fixed limit of 3 mg kg¡1 for the sum of heavy PAHs (BaP, DaA, BaA, BbF, BkF, Cry, and Bghi), calculated on the basis of the toxic equivalent factor (TEF). Our results for milk samples did not breach the permissible limit of sum of PAHs for PAH4: BaP, Cry, BbF, and BaA; or PAH8: BaP, Cry, BbF, BaA, BkF, Bghi DaA, and Ind, which have been considered as ecotoxicologically relevant compounds in recent studies.[12] Possible sources of contamination Some authors use individual PAHs to identify possible sources in the affected area. For example, where burning
Fig. 2. Average distribution of individual aromatic compounds in milk samples.
Guti errez et al. of trees is the source, the representative aromatic compounds are Phe, Ant, Fla, and Pyr; for burning of carbon and grass Pyr, BaA, and Cry; for biological sources Nap and Perylene, and other individual compounds for other polluting sources. However, it should be borne in mind that environmental variables and other factors such as metabolism can change the distribution and levels of pollutants so it is not always possible to trust these descriptions alone. The use of diagnostic ratios is useful to identify possible contamination sources for environmental samples.[12,14] For this study, we used the following diagnostic ratios: Fla/(FlaCPyr), Phe/(PheCAnt), Ant/(AntCPhe), Ind/ (IndCBghi), and BaA/(BaACCry) which indicate the main sources of combustion processes (fuels and vegetation) (Table 3). The slight increase in medium and high molecular weight compounds seen in Figure 1 is probably a result of the growth of industries near the industrial farms. This indicates a likely increase of PAH contamination in the raw milk. According to Yebra-Pimentel et al.,[16] the presence of PAHs in cow’s milk is probably caused by contamination of food from a polluted atmosphere, which is then transferred to plants generally by particle-phase deposition on the waxy leaf cuticle or by uptake in the gas phase through stomata. In fact, uptake of gaseous chemicals by plants is one of the major pathways of many semi-volatile contaminants including PAHs into the agricultural food chain and is a key process in determining human exposure. Foodstuff contamination by PAHs could also occur during intense thermal drying processes, toasting, roasting or frying by direct pyrolysis of food nutrients and due to direct deposition of PAHs from smoke produced through incomplete combustion of different thermal agents. PAHs pollution in feed occurs not only due to their fiber content but also due to other components such as minerals and additives.[10,11,12] Contamination of these products (cereals, fiber products, minerals and additives) by PAHs could occur at source (e.g., by atmospheric deposition on crops), but in the main does so during intense thermal processing (drying and toasting). Many PAHs once ingested suffer chemical transformations to secondary metabolites,[17] although the original compounds are often detected in milk samples.[18] For the case of raw milk samples, the presence of PAHs is probably due to contamination of pasture by atmospheric deposition, in industrial areas. According to Smith and Jones[19] there is a clear association of atmospheric contaminants and plants by gaseous exchange and waxes of plants (alfalfa). According to Lapole et al.[20] the production ingredients of food for cattle have a high concentration of carcinogen PAHs (BaP 2 to 10 mg kg¡1). The transfer of PAHs in milk by this the main pathway results in contamination, although these compounds are metabolized quickly once
321
Presence of PAHs in milk of industrial farms from Tizayuca, Hidalgo, Mexico Table 3. Possible sources of PAHs in milk samples of Tizayuca, Hidalgo.
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2008
2009
2010
Diagnostic Ratios
Dry
Wet
Dry
Wet
Dry
Wet
Source
Fla/(FlaCPyr) Phe/(PheCAnt) Ant/(AntCPhe) Ind/(IndCBghi) BaA/(BaACCry)
0.50 0.37 0.62 1.00 0.65
0.50 0.37 0.62 1.00 0.65
0.64 0.12 0.87 0.17 0.60
0.65 0.40 0.60 0.60 0.83
0.55 0.31 0.69 0.69 0.62
0.31 0.27 0.73 0.73 0.85
Fuels combustion Vegetation combustion Fuels combustion Fuels combustion Wood, grass, coal combustion
ingested and the concentration in the recipient species is diminished.[10]
Conclusion It is necessary that the government regulate pollutant emissions in industrial areas in order to protect the quality of food produced near these areas. The presence of PAHs in the environment and food are likely to contribute to health problems, even at low doses as bioaccumulation may occur over the long term.
Funding The authors thank the Metropolitan Autonomous University “Xochimilco” Campus for providing the financial support and sponsoring the research work.
References [1] Cai, Q.Y.; Mo, C.H.; Li, Y.H.; Zeng, Q.Y.; Katsoyiannis, A.; Wu, Q.T.; Ferard, J.F. Occurrence and assessment of polycyclic aromatic hydrocarbons in soils from vegetable fields of the Pearl River Delta, South China. Chemosphere. 2007, 68, 159–168. [2] Rey-Salguerio, L.; Martínez-Carballo, E.; García-Falc on, M.; Simal-Gandara, J. Effects of a chemical company fire on the occurrence of polycyclic aromatic hydrocarbons in plants foods. Food Chem. 2008, 108, 347–353. [3] Hernandez, M.; Vidal, J.V.; Marrugo, J.L. Plaguicidas organoclorados en leche de bovines suplementados con residues de algod on en San Pedro, Colombia. Rev. Salud Publica. 2010, 12, 982–989. [4] Kluska, M. Soil contamination with polycyclic aromatic hydrocarbons in the vicinity of the ring road in Siedle City. Polish J. Environ. Studies, 2003, 12, 309–380. [5] Kampire, E.; Kiremire, B.T.; Nyanzi, S.A.; Kishimba, M. Organochlorine pesticide in fresh and pasteurized cow’s milk from Kampala markets. Chemosphere. 2011, 84, 923–927. [6] Aktar, W.; Sengupta, D.; Chowdhury, A. Impact of pesticides use in agriculture: their benefits and hazards. Interdiscip Toxicol. 2009, 2, 1–12. [7] Yarto, Y.; Gavilan, A.; Barrera, J. Stockholm agreement over persistent organic pollutants and implications in Mexico. Gaceta Ecol ogica, Instituto Nacional de Ecología: Mexico City, Mexico. 2003, 69, 7–28.
[8] Frank, R.; Smith, E.H.; Braun, H.E.; Holdrinet, M.; McWade, J. W. Organochlorine insecticides and industrial pollutants in the milk supply of the Southern Region of Ontario. Canada J. Milk Food Technol. 1975, 38, 65–72. [9] EPA (Environmental Protection Agency-US). Method 8100. Polynuclear aromatic hydrocarbons, 1986. Available at http://www. epa.gov/osw/hazard/testmethods/sw846/pdfs/8100.pdf. (accessed Jun 2014) [10] Purcaro, G.; Moret, S.; Conte, L.S. Overview on polycyclic aromatic hydrocarbons: Occurrence, legislation and innovative determination in foods. Talanta. 2013, 105, 292–305. [11] Ounnas, F.; Jurjanz, S.; Dziurla, M.A.; Guiavarch, Y.; Feidt, C.; Rychen, G. Relative bioavailability of soil-bound polycyclic aromatic hydrocarbons in goats. Chemosphere. 2009, 77, 115–122. [12] Grova, N.; Feidt, C.; Crepineau, C.; Laurent, C.; Lafargue, P.E.; Hachimi, A.; Rychen, G. Detection of polycyclic aromatic hydrocarbon levels in milk collected near potential contamination sources. J. Agr. Food Chem. 2002, 50, 4640–4642. [13] Chung, T.L.; Liao, C.J.; Chen, M.F. Comparison of liquid-liquid extraction and solid phase extraction for the determination of polycyclic aromatic hydrocarbons in the milk of Taiwan. J. Taiwan Inst. Chem. Eng. 2010, 4, 178–183. [14] Braga, J.D.; García, J.; Monego, E.; Calesso, E.; Stefens, J.L.; Wiegand, F. Polycyclic aromatic hydrocarbons in atmospheric particles in the metropolitan area of Porto Alegre, Brazil. Atmos. Environ. 2005, 39, 1609–1625. [15] Cheng, Y.; Wang, Ch.; Wang, Z. Residues and source identification of persistent organic pollutants in farmland soils irrigated by effluents from biological treatment plants. Environ. Int. 2005, 31, 778–783. [16] Yebra-Pimentel, I.; Fern andez-Gonz alez, R.; Martínez, E.; SimalG andara, J. Searching ingredients polluted by polycyclic aromatic hydrocarbons in feeds due to atmospheric or pyrolytic sources. Food Chem. 2012, 135, 2043–2051. [17] Lutz, S.; Feidt, C.; Monteau, F.; Rychen, G.; Le Bizec, B.; Jurjanz, S. Effect of exposure to soil bound polycyclic aromatic hydrocarbons on milk contaminations of parent compounds and their monohydroxykated metabolites. J. Agric. Food Chem. 200, 54, 263–268. [18] Costera, A.; Feidt, C.; Dziurla, M.A.; Monteau, F.; Le Bizec, B.; Rychen, G. Bioavailability of polycyclic aromatic hydrocarbons (PAHs) from soil and hay matrices in lactating goats. J. Agric. Food Chem. 2009, 57, 5352–5357. [19] Smith, K.E.C.; Jones, K.C. Particles and vegetation: implications for the transfer of particle-bound organic contaminants to vegetation. Sci. Total Environ. 2000, 246, 207–236. [20] Lapole, D.; Rychen, G.; Grova, N.; Monteau, F.; Le Bizec, B.; Feidt, C. Milk and urine excretion of polycyclic hydrocarbons and their hydroxylated metabolites after a single oral administration in ruminants. J. Dairy Sci. 2007, 90, 2624–2629.
