Using PCDD/F congener patterns to determine the source of elevated TEQ concentrations in cows milk: a case study

Dioxin transfer simulation from feed to animal tissues and risk assessment

Dioxins might be introduced into the food chain through a direct or an indirect pathway. The main source of human exposure to dioxins is food of animal origin, whereas feeds are the main route of exposure of farmed animals to dioxins and polychlorinated biphenyls. The aim of the study was to simulate dioxin passage from feed to tissues on farm animals using transfer models, and, in addition, to assess the risk to consumers of food of animal origin. From over 700 feed samples analyzed over the course of 9 years (2013-2021), those exceeding the maximum permissible levels set down in Commission Regulation No 277/2012/EU were selected. These samples being derived from real cases of dioxin contamination made it possible to present the most realistic picture of the effects these feed materials could have had if they had entered the food chain. Three species of animals were selected (laying hens, dairy cattle and slaughter pigs), for which feed materials with dioxin contents exceeding the maximum permissible level were selected in accordance with the nutritional recommendations. The calculated PCDD/PCDF concentrations in chicken eggs, cow's milk and pork were above the maximum permissible level in most cases.

PCDD/F levels and phase distributions in a full-scale municipal solid waste incinerator with co-incinerating sewage sludge

Co-incinerating sewage sludge in municipal solid waste incinerators (MSWIs) is an up-to-date disposal way with great prospects to market. To verify the environmental safety of this disposal method, a field study was conducted in a MSWI which has achieved PCDD/Fs ultra-low emission. PCDD/F phase partitioning characteristics, congener profiles, and the influence of selective catalytic reduction (SCR) were also investigated. PCDD/F emission levels ranged from 0.0031 to 0.0053 ng I-TEQ/Nm³, distinctly lower than the national standard. For tests co-incinerating 5% sludge, PCDD/F emission levels were averagely 32% lower than tests mono-combusting municipal solid waste. The phase partitioning study found that PCDD/Fs enriched in condensed water took a non-negligible proportion of the total concentration in flue gas. The removal efficiency of SCR in tests co-incinerating sludge was averaged at 41.9%. However, in tests without adding sewage sludge, PCDD/F concentrations in flus gas after SCR were increased. It was found that the elevations were mainly attributed to the increase of low-chlorinated PCDF congeners in gas-phase. By inference, memory effect existing in SCR might be responsible for the increase of PCDD/F levels. PCDD to PCDF ratios in most of the sampling points were >1, suggesting that de novo synthesis is not the dominant formation pathway in the studied incinerator. This study verified that co-incinerating sewage sludge in the MSWI would not elevate the emission levels of PCDD/Fs. If all of the yielded municipal waste is incinerated with adding 5% sewage sludge, more than half of sewage sludge can be disposed safely in Shenzhen.

Occurrence, variability and human exposure to Polychlorinated Dibenzo-p-dioxins (PCDDs), Polychlorinated Dibenzofurans (PCDFs) and Dioxin-Like Polychlorinated Biphenyls (DL-PCBs) in dairy products from Chile during the 2011-2013 survey

Levels, congener profiles of PCDD/Fs, DL-PCBs and human exposure for these xenobiotics never have been reported in Chile. For that purpose 102 raw cow milk samples were collected from seven different regions of Chile during 2011 until 2013. The highest mean level for PCDD/Fs, corresponds to 0.32 pg WHO-TEQ2005 g(-1) fat (2012) and for DL-PCBs 0.17 pg WHO-TEQ2005 g(-1) fat (2011), using the upper bound approach. Penta and tetra chlorinated congeners dominated PCDD/Fs profiles in a WHO-TEQ2005 basis during the survey. In the case of DL-PCBs, PCB 126 dominated the profiles with 89%. Statistical analysis showed significant difference among years only in DL-PCBs residues. Also dietary intake was estimated, and the highest level for total sum of PCDD/Fs and DL-PCBs for adult was 0.16 pg WHO-TEQ kg(-1) b.w d(-1) (2011) and for children correspond to 0.65 pg WHO-TEQ kg(-1) b.wd(-1) (2011). Concentrations and dietary intake for the studied compounds in milk and butter samples were below international and national regulations.

A survey of dioxins (PCDDs and PCDFs) and dioxin-like PCBs in sheep and goat milk from Campania, Italy

In 2008, after the crisis of buffalo dairy fields in Campania, Italy, an assessment of the contamination of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) was also necessary for other animal species bred in the region. The contents of PCDDs, polychlorinated dibenzofurans (PCDFs), and dl-PCBs were determined by high-resolution gas chromatography/mass spectrometry (HR-GC/MS) (according to USEPA method 1613) in 69 sheep and goat milk samples from 63 farms. In eleven samples from six sheep farms, the PCDD/Fs levels exceeded the maximum limit of 3.0 pg g(-1) fat established by the European Commission, in particular the concentrations ranged between 3.89 and 12.90 pg g(-1) fat. Statistical treatment of the results for the congener profiles of the non-compliant and compliant samples has been used to identify the sources of contamination.

Contamination levels and congener distribution of PCDDs, PCDFs and dioxin-like PCBs in buffalo's milk from Caserta province (Italy)

An extraordinary plan of official control was carried out in 2008 in Campania (Italy) with the aim to monitor polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) levels in buffalo milk and to detect the contaminated farms, most of which are located in Caserta province. For these companies has been ordered seizure and execution of additional analyses has been requested in farms falling in the nearness, within a distance of 3km, for a total of 304 farms examined. Moreover, all non-compliant farms were subjected to a periodic sampling in order to monitor trends in the levels of contamination. In this paper the distribution and the concentrations of 17 PCDD/Fs and 12 dioxin-like PCBs in 460 samples of buffalo milk collected in the province of Caserta (Italy) are presented. The range of WHO-TEQ values for the PCDD/Fs in milk was 0.17pgTEQg(-1)fat and 87.0pgTEQg(-1)fat with a mean value 3.63pgTEQg(-1)fat and medium value 2.25pgTEQg(-1)fat. The concentrations of dioxin-like PCBs in the analysed samples ranged from 0.21pgTEQg(-1)fat to 15.9pgTEQg(-1)fat and the WHO-TEQ values of sum of PCDDs, PCDFs and dl-PCBs ranged from 0.45pgTEQg(-1)fat to 103.0pgTEQg(-1)fat. The geo-referencing analysis allowed to individuate a restricted area of the region object of the present study where is located the majority of the non-compliant farms. The study of the congeners distribution has finally suggested that the likely cause of contamination is to be attributed to the illegal burning of waste.

Exposure assessment at a PCDD/F contaminated site in Sweden--field measurements of exposure media and blood serum analysis

BACKGROUND, AIM, AND SCOPE

The main pathway for human exposure to the highly toxic polychlorinated-p-dioxins and polychlorinated furans [polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs)] is via dietary intake. Other exposure pathways may, however, be important in close proximity to point sources, such as wood preservation sites, where PCDD/F contaminated chlorophenols (CP) were previously used. In this study, a heavily PCDD/F contaminated CP saw mill site in Sweden was investigated. Human exposure through a broad spectrum of exposure pathways was assessed. Such studies are in demand since the question whether contaminated sites represent a current or future risk can only be answered by detailed site-specific risk assessments.

MATERIALS AND METHODS

Sampling of exposure media (soil, air, groundwater, raspberries, carrots, potatoes, grass, milk, eggs, and chicken fodder) was made. Exposure media concentrations and congener distribution patterns were used to investigate the mobilization of PCDD/Fs from soil to the environment and to calculate exposure levels for adults. Blood serum levels from site-exposed and control individuals were also analyzed.

RESULTS

Congener distribution patterns at the site were generally dominated by a specific marker congener (1234678-HpCDF), which is highly abundant in the polluted soil. The dioxin toxic equivalents (TEQ) concentrations were notably elevated as compared to national reference samples for most exposure media, and the marker congener was a major contributor to increased TEQ levels. There were also indications of soil-to-air volatilization of tetra- and penta-CDD/Fs. People who participated in the restoration of a contaminated building showed higher levels of 1234678-HpCDF compared to controls, and calculated exposure levels suggest that several site-specific exposure routes may be of importance for the daily intake of PCDD/F. CONCLUSIONS, RECOMMENDATIONS, AND PERSPECTIVES: Despite low mobility of higher chlorinated PCDD/Fs, these contaminants were transferred from the polluted soil to the surroundings and into human tissue. The extent of increased exposure from contaminated sites depends on the PCDD/F source strength of the soil, composition of the pollution, human activities, and dietary patterns of the residents. Impact from the contaminated soil on other exposure media was seen also for areas with low to moderate soil contamination. In the future, not only the levels of PCDD/F soil pollution but also the composition must be considered in risk assessments of contaminated sites.

Levels and congener profiles of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls in cow's milk collected in Campania, Italy

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and certain dioxin-like polychlorinated biphenyls (dl-PCBs) are a family of chemically-related lipophilic compounds characterized by similar toxicity. Due to their properties they are universally distributed in the environment and classified as persistent organic pollutants (POPs). From most of studies carried out to evaluate human dietary intake, milk and dairy products result as a major contributors of PCDD/Fs uptake. Of course the main source of milk contamination is animal feeds. Lactating ruminants, cows included, transfer these compounds to the food chain by ingestion of contaminated vegetables or soil. Their resistance to degradation and a high lipophilicity means that PCDD/Fs and dl-PCBs may be accumulated into fat tissues from which they are transferred to milk during lactation period. Seventy-nine cows milk samples, collected in the monitoring plan 2008, were analyzed for PCDD/Fs and dl-PCBs. Eleven milk samples were non-compliant corresponding to five breeding livestock located in Caserta province. The distribution of PCDD/Fs and dl-PCBs congeners in these samples was examined in order to determine the likely sources of dioxins. The results show that the congener profile is characterized by a prevalence of PCDFs in respect of PCDDs, that represents the typical pattern of thermal origin contamination.

Measurement of atmospheric PCDD/F and PCB distributions in the vicinity area of Waelz plant during different operating stages

A comprehensive sampling program was conducted at four sampling sites in the vicinity area of a Waelz plant prior to and after the retrofitting of this plant for reducing PCDD/F (polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran) and polychlorinated biphenyl (PCB) emission to evaluate its effects on atmospheric PCDD/F and PCB concentrations. During the shutdown stage of the Waelz plant investigated, the atmospheric PCDD/F and PCB concentrations measured in the vicinity area (sites A, B and C) range from 24 to 170 fg-I-TEQ/m(3) and 5.0 to 8.2 fg-TEQ(WHO)/m(3), respectively. As the facility restarted to operate, the atmospheric PCDD/F and PCB concentrations measured increased to 570-1460 fg-I-TEQ/m(3) and 23-59 fg-TEQ(WHO)/m(3), respectively. When activated carbon injection (ACI) was adopted in the facility in early 2006, the PCDD/F concentrations measured in stack gas decreased dramatically from 190 to 3.4 ng-I-TEQ/Nm(3), while the PCB concentrations decreased from 4.9 to 0.08 ng-TEQ(WHO)/Nm(3). In the meantime, the atmospheric PCDD/F and PCB concentrations measured at sites A, B and C decreased to 150-340 fg-I-TEQ/m(3) and 13-19 fg-TEQ(WHO)/m(3), respectively. However, relatively high PCDD/F (180-1460 fg-I-TEQ/m(3)) and PCB (9.3-59 fg-TEQ(WHO)/m(3)) concentrations were measured at site D during all sampling stages. Overall, atmospheric sampling results indicate that over 50% of PCDD/Fs distributed in solid phase, while over 90% of PCBs distributed in vapor phase during all sampling stages.

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in China and chemometric analysis of potential emission sources

Aimed to give a preliminary image of dioxin pollution in China, chemometric analysis was performed to determine background dioxin levels during the period 1994-2002 and potential emission sources. Using principal components analysis (PCA), the congener profiles of 71 sediment samples from rivers, lakes, and sea bays around China were compared with the congener profiles of various known or suspected industrial, residential, and municipal dioxin sources to determine whether the dioxin residues typically found in a broad range of potential environmental sources could explain the presence of these chemicals in China. It was found that the background dioxin levels of China were similar to those of lightly polluted samples from other countries during the period 1994-2002. Primary ferrous ore sintering and secondary lead and aluminum smelters were the major sources of dioxin emission in China. Chloranil and wastewater from chemical plants, sodium pentachlorophenate, and pulp bleaching were also important sources of dioxin emission. Open burning of e-waste as well as diesel-fueled and leaded gas-fueled vehicles were additional possible sources of dioxin. In contrast to other countries, in China, flue gases from incineration of municipal waste, hazardous waste, and medical waste might be minor sources of dioxin emission.

Background levels and dietary intake of PCDD/Fs in domestic and imported meat in South Korea

A survey was conducted in South Korea to determine residual levels and dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) from meat. Altogether 119 domestic and 164 imported samples of beef, pork, and chicken were examined. The mean levels of PCDD/Fs in upper bound were 0.21, 0.22, and 0.04pg WHO-TEQ/g fat for beef, pork, and chicken, respectively. The low level of PCDD/Fs in chicken probably resulted from the low fat content in the samples used. The samples were separated into domestic and imported products in order to investigate the sources of contamination. PCDFs were the more dominant congeners in domestic beef and were similar to those found from emission of incineration. However, the congener profiles of domestic beef and incineration were difficult to compare because the environmental fate and animal metabolism were involved. The upper bound dietary intake of PCDD/Fs from beef, pork and chicken was calculated to be 0.04pg/WHO-TEQ/kgbw/day. The combined consumption of beef, pork, and chicken was found to be 84.8g per day for a person weighing 60kg and represented 5.7% of their total daily food intake.

Effects of river flooding on PCDD/F and PCB levels in cows' milk, soil, and grass

This paper presents the results of a study examining whether the flooding of pasture by rivers gives rise to higher PCDD/F and PCB concentrations in cows' milk. Over 180 milk, soil, and grass samples, taken from 38 farms across 3 different river systems (River Dee, Trent, and Doe Lea/Rother/Don) in the United Kingdom, were analyzed for PCDD/Fs and PCBs. The concentrations were compared between flood-prone farms, where the animals had access to pasture that is often flooded, and control farms where the land does not flood. The results indicated that concentrations of PCDD/Fs and PCBs in cows' milk were higher in samples taken from farms prone to flooding, but only from the river systems flowing through industrial and urban areas. Raised levels of PCDD/F and PCBs were also found in soil and grass from farms prone to flooding providing strong corroborative evidence that the higher concentrations in cows' milk from such areas is likely to be due to the ingestion of contaminated grass and soil. Overall, the results provide strong evidence that flooding of pastureland can indeed result in elevated concentrations of PCDD/Fs and PCBs in milk from the farms so affected.

Butter as an indicator of regional persistent organic pollutant contamination: further development of the approach using polychlorinated dioxins and furans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (PCBs)

The potential for use of butter as a widely available, relatively uniform lipid-rich matrix for the determination of spatial distributions of persistent organic pollutants has already been demonstrated. The present study determines the contributions to toxicity equivalence (TEQ) from polychlorinated dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) using butter samples from 24 countries world wide. Concentrations of PCDD/Fs and dioxin-like PCBs ranged from 0.07 to 5.69 pg SigmaWHO-TEQ g(-1) lipid. For most samples, PCDD/F TEQ fell within ranges reported for European dairy products over the last decade (0.3-2 pg x g(-1) lipid I-TEQ), though a single sample from Spain was a notable exception. Other than this sample, the highest values were recorded for samples from the Netherlands and Italy, with those from India, China and Tunisia also being relatively high. The contribution from non-ortho-PCBs was particularly significant in samples from Germany, Austria, Italy, the Czech Republic, Tunisia, India and Argentina. Although overall TEQs were generally highest in European and Mediterranean butters, elevated levels were also apparent in industrializing regions of Asia (India, China) and Latin America (Argentina). More detailed regional studies would be necessary to identify likely dioxin and PCB sources in each case. Nevertheless, this study supports the utility of butter as a monitoring matrix that may be especially applicable in regions for which monitoring programmes are currently lacking.