Presence of PAHs in milk of industrial farms from Tizayuca, Hidalgo, Mexico

Industrial impact on sustainable dairy farms: Essential elements, hazardous metals and polycyclic aromatic hydrocarbons in forage and cow's milk

Sustainable dairy farms are characterised by the self-production of forage for animal feed. These farms are sometimes located near industrial areas, entailing a risk of food chain contamination with hazardous metals and polycyclic aromatic hydrocarbons (PAHs). Accordingly, evaluating the impact of pollution on forage and milk is of great interest. In this study, the effects of industrial factors on sustainable forage from 43 dairy farms and possible correlations between inorganic elements and PAHs were studied. Spearman's correlation and principal component analysis (PCA) were performed for the forage and milk. Most of the inorganic elements in the forage were below the maximum residual limits for cadmium (Cd) and lead (Pb), established in EU 2013/1275 and EU 2019/1869, respectively. However, arsenic (As) and mercury (Hg) levels were above their respective limits in the forage (EU 2019/1869). No milk samples exceeded the maximum residual limits for Pb (EU 488/2014) or Cd (EU 1881/2006) in dairy products. Heavy-weight PAHs (HW-PAHs, four or more aromatic rings) were detected in forage but not in milk. In the forage samples, HW-PAHs were positively correlated with Zn and Cd. In addition, some hazardous metals (chromium (Cr), iron (Fe), As, Hg, and Pb) also were positively correlated with Zn and Cd. Interestingly, no correlations were found between forage pollutants and milk, suggesting that these pollutants have a low transfer rate to milk. The PCA results highlighted the predominant contribution of PAHs to the global variance in forage samples collected at different distances from industrial areas. In milk, the contributions of hazardous metals and PAHs were more balanced than in forages. Finally, when distances to potential pollution sources were included in the PCA of forage samples, a negative correlation was observed between the former and the concentrations of HW-PAHs, Cd, and Zn, suggesting that thermal power plants and steel factory emissions were the main sources of polluting forage in this area.

Impact of Potentially Toxic Compounds in Cow Milk: How Industrial Activities Affect Animal Primary Productions

Potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) frequently coexist in soils near industrial areas and sometimes in environmental compartments directly linked to feed (forage) and food (milk) production. However, the distribution of these pollutants along the dairy farm production chain is unclear. Here, we analyzed soil, forage, and milk samples from 16 livestock farms in Spain: several PTEs and PAHs were quantified. Farms were compared in terms of whether they were close to (<5 km) or far away from (>5 km) industrial areas. The results showed that PTEs and PAHs were enriched in the soils and forages from farms close to industrial areas, but not in the milk. In the soil, the maximum concentrations of PTEs reached 141, 46.1, 3.67, 6.11, and 138 mg kg^-1 for chromium, arsenic, cadmium, mercury, and lead, respectively, while fluoranthene (172.8 µg kg^-1) and benzo(b)fluoranthene (177.4 µg kg^-1) were the most abundant PAHs. Principal component analysis of the soil PTEs suggested common pollution sources for iron, arsenic, and lead. In the forage, the maximum contents of chromium, arsenic, cadmium, mercury, and lead were 32.8, 7.87, 1.31, 0.47, and 7.85 mg kg^-1, respectively. The PAH found in the highest concentration in the feed forage was pyrene (120 µg kg^-1). In the milk, the maximum PTE levels were much lower than in the soil or the feed forages: 74.1, 16.1, 0.12, 0.28, and 2.7 µg kg^-1 for chromium, arsenic, cadmium, mercury, and lead, respectively. Neither of the two milk samples exceeded the 20 µg kg^-1 limit for lead set in EU 1881/2006. Pyrene was the most abundant PAH found in the milk (39.4 µg kg^-1), while high molecular weight PAHs were not detected. For PTEs, the results showed that soil-forage transfer factors were higher than forage-milk ratios. Our results suggest that soils and forages around farms near industries, as well as the milk produced from those farms, have generally low levels of PTE and PAH contaminants.

Polycyclic Aromatic Hydrocarbons (PAHs) Sample Preparation and Analysis in Beverages: A Review

The monitoring of food contaminants is of interests to both food regulatory bodies and the consumers. This literature review covers polycyclic aromatic hydrocarbons (PAHs) with regard to their background, sources of exposures, and occurrence in food and environment as well as health hazards. Furthermore, analytical methods focusing on the analysis of PAHs in tea, coffee, milk, and alcoholic samples for the last 16 years are presented. Numerous experimental methods have been developed aiming to obtain better limits of detections (LODs) and percent recoveries as well as to reduce solvent consumption and laborious work. These include information such as the selected PAHs analyzed, food matrix of PAHs, methods of extraction, cleanup procedure, LOD, limits of quantitation (LOQ), and percent recovery. For the analysis of tea, coffee, milk, and alcoholic samples, a majority of the research papers focused on the 16 US Environmental Protection Agency PAHs, while PAH4, PAH8, and methylated PAHs were also of interests. Extraction methods range from the classic Soxhlet extraction and liquid–liquid extraction to newer methods such as QuEChERS, dispersive solid-phase microextraction, and magnetic solid-phase extraction. The cleanup methods involved mainly the use of column chromatography and SPE filled with either silica or Florisil adsorbents. Gas chromatography and liquid chromatography coupled with mass spectrometry or fluorescence detectors are the main analytical instruments used. A majority of the selected combined methods used are able to achieve LODs and percent recoveries in the ranges of 0.01–5 ug/kg and 70–110%, respectively, for the analysis of tea, coffee, milk, and alcoholic samples.

Simultaneous Determination of Typical Chlorinated, Oxygenated, and European Union Priority Polycyclic Aromatic Hydrocarbons in Milk Samples and Milk Powders

An increasing number of studies have suggested that PAH contamination in dairy products demands high concern. This study established an efficient determination method for the European Union 15 + 1 PAHs and four PAH derivatives in dairy samples using a QuEChERS method coupled with GC-QqQ-MS. The optimized method obtained a recovery of 63.38-109.17% with a precision of 3.82-15.62%, and the limit of detection and limit of quantification were 0.08-0.78 and 0.27-2.59 μg/kg, respectively. The validated method was then successfully applied to identify the 20 PAHs in 82 dairy samples, including 43 commercial milk samples and 39 milk powders. The total PAH concentrations ranged from 2.37 to 11.83 μg/kg, and benzo[a]pyrene was only quantified in one milk and one milk powder sample at 0.35 and 0.42 μg/kg, respectively. The concentrations of PAH4 in milk samples and milk powders were not quantified (nq)-3.99 and nq-4.51 μg/kg, respectively. The results confirmed the appreciable occurrence of PAHs in dairy products, especially in infant formula. The data in this study provide a scientific basis for assessment on origin tracing, dietary exposure, and health risk of PAHs and their derivatives.

Monitoring of polycyclic aromatic hydrocarbons and probabilistic health risk assessment in yogurt and butter in Iran

This study was conducted to determine the polycyclic aromatic hydrocarbons (PAHs) levels and health risk of yogurt and butter samples collected from Tehran using MSPE/GC-MS (magnetic solid-phase extraction/gas chromatography-mass spectrometry). The results revealed that the limit of detection (LOD) and limit of quantification (LOQ) were ranged from 0.040 to 0.060 and 0.121 to 0.181 μg/kg, respectively; with recoveries ranged from 86.1% to 100.3%. The highest mean of total PAHs was higher in butter (6.87 ± 1.21 μg/kg) than in yogurt (3.82 ± 0.54 μg/kg). The level of benzo (a)pyrene in all samples was lower than of standard levels of the European Union (EU). The highest value of all PAHs in samples was recorded in the winter season and also in the expiration date. The percentile 95% of the total hazard quotient (THQ) due to the consumption of yogurt and butter recorded 1.33E-02 and 3.69E-04 in adults and 6.12E-02 and 1.75E-03 in children, respectively. The percentile of 95% incremental lifetime of cancer risk (ILCR) due to the ingestion of yogurt and butter recorded 1.17E-06 and 2.02E-08 for adults and 5.51E-06 and 9.46E-08 for children, respectively. The rank order of 7 PAHs in adult and children based on P95% Hazard Quotient (HQ) in all samples was benzo(a)anthracene (BaA) > pyrene (P) > fluorene (F) > fluoranthene (Fl) > acenaphthylene (Ace) > anthracene (A) > naphthalene (NA). According to the Monte Carlo Simulation (MCS) method, health-risk assessment showed that children and adults are not at significant health risk.

Distribution and Health Hazards of Polycyclic Aromatic Hydrocarbons in Egyptian Milk and Dairy-Based Products

In a market-basket study conducted in Cairo, Egypt, the most commonly consumed milk products were sampled and the contents of 13 polycyclic aromatic hydrocarbons were analyzed using gas chromatography with a mass spectrometer detector. The obtained data showed that the total amount of 13 PAHs was within the range of 1.3–8.2 µg/g. The results proved that the, highest mean levels of polycyclic aromatic hydrocarbons were detected in powdered milk (8.2 μg/g) followed by ultra-heat treatment milk and milk beverages (6.07 μg/g). The lowest level was detected in unsmoked cheese and yogurt (1.3 μg/g). Estimated daily intake (EDI) was used to estimate the carcinogenic risk. The total mean estimated daily intake for children in different age categories (1–10 years) was calculated with respect to benzo[a]pyrene, which ranged from 0.058 to 0.31 mg/day. The total mean value of EDI for the sum of seven carcinogenic PAHs in terms of benzo[a]pyrene ranged from 0.61 to 1.22 mg/day in all age categories. These results were higher than the critical limit set by the European Food Safety Authority. Therefore, there should be concerns regarding the effects of the consumption of different milk products on the local population.

Polycyclic aromatic hydrocarbons in milk powders marketed in Uruguay

Polycyclic aromatic hydrocarbons (PAHs) occurrence in forty-four samples of milk powder, marketed in Uruguay, was determined. A high-performance liquid chromatography (HPLC) method was applied with fluorescence detector (FLD) and UV-VIS diodes array detector (DAD). Milk powder was fortified with PAHs at three levels producing average recovery higher than 78.6% for all levels. The highest concentration of benzo(a)pyrene (BaP) was 2.85 μg kg^-1 in milk powder. Contamination of samples expressed as the sum of 16 analysed PAHs varied between 5.77 and 427.28 μg kg^-1 and as PAH4 (BaP, chrysene, benzo(a)anthracene and benzo(b)fluoranthene) was between below LOD and 11.54 μg kg^-1. Only one sample exceeded the maximum limit for BaP, but 84% of the commercial milk powders did not comply with the European Union maximum limit for PAH4.