Dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans) in traditional clay products used during pregnancy

Hypokalaemia in pregnancy - Prevalence, underlying causes, and an approach to investigation

Objective

To investigate the prevalence and aetiology of hypokalaemia in pregnancy.

Methods

This was a five-year retrospective audit of women who received care at a tertiary hospital, who developed hypokalaemia during pregnancy and within three weeks postpartum. Serum potassium and magnesium levels cause(s) of hospitalization and investigations for hypokalaemia were obtained from hospital records.

Results

One hundred and ten women developed hypokalaemia during pregnancy and the immediate postpartum period, representing 0.36% of total births. Ninety-one per cent of patients had mild to moderate hypokalaemia (K 2.6-3.1 mmol/L), while 9% had severe hypokalaemia (K < 2.6 mmol/L). The most common associations of hypokalaemia were infection (38%), vomiting (18%), hypertensive disorders (12%) and postpartum haemorrhage (9%). Twenty-four patients did not have a clear underlying aetiology of hypokalaemia, but only five had further investigations.

Conclusions

There was inadequate investigation and follow-up of hypokalaemia, particularly in women in whom an obvious cause was not apparent.

African migrant women acquisition of clay for ingestion during pregnancy in London: a call for action

OBJECTIVES

This study aimed to explore how African migrant women go about acquiring clay for ingestion during pregnancy in London against a backdrop of restrictions and warnings by the Food Standard Agency and Public Health England due to the potential health risks to expectant mothers and their unborn babies.

STUDY DESIGN

This was a qualitative study using an interpretative phenomenological approach.

METHODS

Individual in-depth interviews and a focus group discussion were used for data collection. Data collection took place between May and August 2020.

RESULTS

Participants acquired clay from African shops and markets in London, countries of origin and online/social media platforms. Due to official restrictions and warnings, transactions were conducted under the counter based on trust between sellers and the women underpinned by shared community identities. However, clay was acquired, social networks emerged as crucial facilitators. The current top-down approach, which is also lacking a regulatory policy framework, has pushed clay transactions underground, thereby leaving pregnant women potentially ingesting toxic clay with little chances of dictation by authorities.

CONCLUSION

We call on the UK Health Security Agency (UKHSA) and public health practitioners to collaborate with communities to design multilevel/multisectoral interventions as well as the Food Standards Agency (FSA) to consider an appropriate regulatory policy framework.

Micro problems with macro consequences: accumulation of persistent organic pollutants and microplastics in human breast milk and in human milk substitutes

Industrial activities provide a modern human lifestyle with advances and comforts in every field. However, such scenario has brought several negative issues. Persistent organic pollutants (POPs) and a growing plastic usage together with the degradation byproducts, namely microplastics (MPs), are current environmental problems present in every ecosystem, disturbing all forms of life. POPs and MPs are also found in human consumption products including animal and vegetal derivatives, human milk substitutes, and in human breast milk. To date, it is currently unknown what are the effects of MPs and POPs when ingested during the first and most important stage for health programming of the offspring, the first 1000 days of life. Here, we add epidemiological and clinical evidence supporting major sources of POPs and MPs in the ecosystem; and we will precisely describe the effect of POP and MP accumulation in animal- or plant-based infant formulas and human breast milk, modulating health outcomes in the newborn. This review provides a rational to incentive the POP and MP identification in human breast milk and human milk substitutes for avoiding susceptibility to negative health outcomes for the newborn.

Fingerprinting and source apportionment of dioxin contamination of soils and chicken eggs in Southeast and Central Vietnam

Free-range chicken eggs and topsoil samples from private households in Southeast and South Central Coast of Vietnam were investigated to identify potential PCDD/F sources using Positive Matrix Factorization (PMF) approach. The PMF-extracted egg congener patterns were transformed to soil patterns using bioaccumulation factors and then compared to extracted soil and known dioxin sources patterns described in the literature. Free-range chicken egg PCDD/F profiles allowed to more precisely identify and distinguish potential PCDD/F sources. Five main PCDD/F sources were identified: open burning, vehicle emissions, background atmospheric deposition, Agent Orange, and so-called OCDD dechlorination pattern. The latter is characteristic for natural formation or ultimate weathering under tropical conditions of any primary source with predominant OCDD. Agent Orange source contribution ranged from 48 to 96% in soils, from 9 to 94% in eggs in hotspots, and from 10 to 31% in soil and from 4 to 45% in eggs in sprayed areas, respectively. Contributions of other sources varied significantly between sites.

Remote Fieldwork With African Migrant Women During COVID-19 Pandemic in London: A Reflection

As coronavirus disease 2019 (COVID-19) pandemic unraveled, state-led preventative restrictions created a "new" normal through remote home-working. A long-planned follow-up qualitative research study on risk perceptions and experiences regarding Clay Ingestion among black African women during pregnancy, in London, was disrupted as England went into lockdown. Against this backdrop, we shifted to remote data collection which raised pertinent concerns around access to technology and participant digital skills. We share our experiences of navigating through remote fieldwork during the pandemic with black African mothers with caring responsibilities as well as the extra burden of homeschooling, the challenges we encountered and how we mitigate these and the lessons learnt. Thus, drawing from our remote qualitative research experiences, we refer to notable examples of challenges, mitigating strategies applied and potential lessons to inform future practice.

Congener patterns of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls as a useful aid to source identification during a contamination incident in the food chain

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) are still considered among the most important groups of contaminants in the food chain. Self-control by food producers and official control by authorities are important activities that allow contaminant sources to be traced and promote further reduction in food and feed levels. Strict but feasible maximum levels were set by the EU Commission for food and feed to support this strategy, as well as action levels and thresholds. When products exceed these levels, it is important to trace the source of contamination and take measures to remove it. Congener patterns of PCDD/Fs and PCBs differ between sources and are important tools for source identification. Therefore, patterns associated with different sources and incidents relating to various feed matrices and certain agricultural chemicals were collated from published scientific papers, with additional ones available from some laboratories. The collection was evaluated for completeness by presentations at workshops and conferences. Primary sources appear to derive from 5 categories, i) by-products from production of organochlorine chemicals (e.g. PCBs, chlorophenols, chlorinated pesticides, polyvinyl chloride (PVC)), ii) the result of combustion of certain materials and accidental fires, iii) the use of inorganic chlorine, iv) recycling/production of certain minerals, and v) certain naturally occurring clays (ball clay, kaolinite). A decision tree was developed to assist in the identification of the source.

Clay Ingestion During Pregnancy Among Black African Women in a North London Borough: Understanding Cultural Meanings, Integrating Indigenous and Biomedical Knowledge Systems

Findings from this qualitative audit conducted in a North London Borough among Black African women show that clay ingestion during pregnancy is a cultural phenomenon embedded in indigenous knowledge (IK). Reasons for clay ingestion include curbing morning sickness, nausea, satisfying cravings, "mineral deficiency" and other life sustaining beliefs. However, Public Health practitioners' top down approach and response which considers the practice as "dangerous" and potentially harmful to the health of the woman and unborn child with midwives and General Practitioner doctors called upon to discourage it, risks alienating the target population. Furthermore, within such a top down framework, opportunities to integrate biomedical science and indigenous knowledge systems are potentially missed. The use of culturally sensitive Public health interventions which consider a community approach, while attempting to integrate these two knowledge systems through further research is likely to bear more fruits.

Mapping polychlorinated dibenzo-p-dioxins/dibenzofurans in soils around Pugu municipal dump site in Dar es Salaam, Tanzania: Implications on dermal and soil ingestion exposure for people in the peripheral

Experimental data on the contribution of a dump site in Tanzania as a point source of the 17 possible congeners of PCDD/Fs to the environment is presented. Dry and wet season samples were collected around Pugu municipal dump site followed by GCxGC-TOFMS analysis. The dominant congeners were OctaCDD, 1,2,3,4,6,7,8-HepCDF; 1,2,3,4,6,7,8-HeptaCDD and 1,2,4,7-PeCDD. The concentrations of the congeners expressed as TEQ WHO₂₀₀₅ ranged from 11.69 to 48.97 pg/g with a mean of 29.44 pg/g for the dry season and TEQ WHO₂₀₀₅ 4.13-85.82 pg/g with a mean of 41.51 pg/g for the wet season. These levels were speculated high enough to accumulate in free-range chickens and cause harmful effects to humans that consumed them especially residents around Pugu dump site. Exposure of people to PCDD/Fs through dermal absorption and soil ingestion were estimated using the VLIER-HUMAAN Mathematical model. Exposure through dermal absorption was estimated to be 1.2 × 10^-4 and 9.8 × 10^-6 ng TEQ/kg day for children and adults respectively while through soil ingestion via consumption of contaminated foods and other sources was 0.0045 and 0.27 ng TEQ/kg day for children and adults respectively. These values however were well below the WHO tolerable daily intake. Generally, there was no significant variation for total PCDD/Fs in the dry and wet season (α = 0.08). Strong positive correlation (r = 0.94) between total PCDD/Fs and organic matter content was observed during the wet season.

Human and environmental exposure to PCDD/Fs and dioxin-like PCBs in Africa: A review

This paper reviews literature for the last two decades with emphasis on levels, toxic equivalencies and sources of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in Africa. Further, we comprehensively analysed data, interpret differences and identify existing gaps with those from other continents. We observed that high levels of PCDD/Fs and dl-PCBs were reported in environmental and biological samples near densely populated urban and industrialised areas compared to those in rural settings. In general, the concentrations of PCDD/Fs and dl-PCBs in the blood samples from Africa were in the same range as those from Asia but lower than those from Europe. The concentrations of dioxins and dioxin-like compounds in the atmosphere in Africa were comparable to and/or higher than those in developed countries. The reported sources of PCDD/Fs and dl-PCBs in Africa were industrial emissions, obsolete pesticide stockpiles, household heating, recycling of electronic waste, and incineration and combustion of domestic waste. Regional and intercontinental transport of dioxins could not be confirmed because of the lack of sufficient literature on them. Further data about the levels and sources of PCDD/Fs and dl-PCBs in Africa need to be generated to complete the chemical inventories for the continent and to facilitate the implementation of the Stockholm Convention on persistent organic pollutants. The reviewed literature shows that most analyses have been carried out in laboratories outside Africa because of the limited institutional capacity in Africa. More support needs to be given to laboratories in Africa to develop the capacity to accurately quantify dioxins on routine basis.

Monitoring polychlorinated dibenzo-p-dioxins/dibenzofurans and dioxin-like polychlorinated biphenyls in Africa since the implementation of the Stockholm Convention-an overview

Polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDF), and dioxin-like polychlorinated biphenyl (dl-PCB) are groups of toxic compounds released into the environment as unintentional by-products of combustion. They persist, bioaccumulate through the food chain, and cause adverse health effects. This review attempts to collate available information on the release of PCDD/Fs and dl-PCBs and other critical data relevant to their monitoring in Africa during the existence of the Stockholm Convention (SC). Much as the implementation of the SC may be lagging, literature showed that there has been encouraging efforts that have been made with respect to PCDDs/Fs and dl-PCBs monitoring in Africa. Results from a global monitoring study showed that PCDD/Fs released to air in Africa stood at 18-532 fg WHO₉₈ TEQ/M³ while dl-PCBs were 7-278 fg WHO₉₈ TEQ/m³. In human milk, the total concentration of PCDD/Fs, i.e., WHO 2005 TEQ LB has been reported to range from 0.5 ng/g fat to 12 ng/g fat. Fourteen laboratories in Africa participated in inter-laboratory assessments of persistent organic pollutants (POPs) with two specifically for PCDD/Fs analysis. This shows that some efforts are being made to boost capacity in Africa. Levels of PCDDs/Fs and dl-PCBs in clay consumed by pregnant women have been reported in Cameroon, Democratic Republic of Congo (DRC), Nigeria, Zimbabwe, Ĉote d'Ivoire, and Uganda with a maximum concentration of 103 pg TEQ/g. This finding was very significant since women are the most impacted through exposure to POPs, a fact that is acknowledged by the SC.

Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food

The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.

Fast extraction of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran in sewage sludge and soil samples

The current environmental legislations recommend monitoring chemical contaminants such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans before the use of sewage sludge on the agricultural land. In this study, a solid-liquid extraction with low-temperature purification (SLE-LTP) was optimized and validated to determine 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzofuran in sewage sludge and soil samples. The analyses were performed by gas chromatography-mass spectrometry operating in the selective ion mode (GC-MS-SIM). Acetonitrile:ethyl acetate 6.5:1.5 (v/v) was the best extraction phase, and the recoveries percentages were close to 100%. The linearity was demonstrated in the range of 1.25-25 µg L^-1 of 1.25-20 µg L^-1 for sewage sludge and soil, respectively. Matrix effect was proved for the two compounds and in the two matrices studied. Extraction percentages were between 78 and 109% and relative standard deviations ≤ 19%. The proposed method is faster than methods described in the literature because showed a few steps. The quantification limits (LOQ) in sewage sludge were 6.4 and 32 ng TEQ kg^-1 for 2,3,7,8-TCDF and 2,3,7,8-TCDD, respectively. In soil, LOQs were 0.8 and 8.0 ng TEQ kg^-1 for 2,3,7,8-TCDF and 2,3,7,8-TCDD, respectively. These values are lower than the maximum residue limits established by European Legislation. The method was applied to 22 agricultural soil samples from different Brazilian cities and 2,3,7,8-TCDF was detected in one of these samples.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human breast milk and associated health risks to nursing infants in Northern Tanzania

This is the first study to report organochlorines (OCs), including chlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human milk from Tanzania. The main aims of this study were to assess the level of contamination and the possible health risks related to OC exposure in nursing infants from the Northern parts of Tanzania. Ninety-five healthy mother-infant couples attending Mount Meru Regional Referral Hospital (MMRRH), Arusha, Tanzania, were assessed for associations between maternal/infant characteristics, i.e. mother's age, BMI, gestational weight gain, occupation, residence and fetal growth parameters and breast milk levels of OCPs, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, dieldrin and PCBs. p,p'-DDE and p,p'-DDT were detected in 100% and 75% of the breast milk samples, respectively, and ranged between 24 and 2400ng/g lipid weight (lw) and <LOD and 133ng/g lw, respectively. Dieldrin was detected in 66% of the samples in levels up to 937ng/g lw. ∑7PCBs ranged between <LOD and 157ng/g lw. Other OCPs were detected in low levels. For assessment of health risks, the Hazard Quotient (HQ) was calculated by comparing estimated daily intakes of OCPs and PCBs with health based guidance values. The estimated daily intake (ng/kg body weight/day) of ∑DDTs, dieldrin and nondioxin-like PCBs (∑6PCBs) exceeded the provisional tolerable daily intake (PTDI) in two, six and forty-eight of the nursing infants, respectively, suggesting potential health risks. In addition, head circumference were negatively associated with p,p´-DDE in female infants, suggesting that OC exposure during pregnancy may influence fetal growth.

WHO/UNEP global surveys of PCDDs, PCDFs, PCBs and DDTs in human milk and benefit-risk evaluation of breastfeeding

Since 1987, the World Health Organization (WHO) carried out global surveys on polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in human milk. This study presents a review of the three most recent surveys from 2000 to 2010, including DDT. The objective was to identify global quantitative differences and provide baseline information for 52 countries or provide time-trends for countries with previous data. Individual human milk samples were collected following a WHO-designed procedure and combined to form a national pooled sample. Here, we report global levels for PCDDs, PCDFs, PCBs and the sum of o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, o,p'-DDD and p,p'-DDD (ΣDDTs). A concise risk-benefit evaluation related to human milk contamination with these persistent organic pollutants (POPs) was also done. Large global and regional differences were observed. Levels of PCDDs and PCDFs were highest in India and some European and African countries. PCB levels were highest in East and West Europe. The highest levels of ΣDDTs were found in less industrialized countries. A temporal downward trend for PCDDs, PCDFs and PCBs is indicated. A risk-benefit assessment indicates that human milk levels of PCDDs, PCDFs and PCBs are still significantly above those considered toxicologically safe, while ΣDDTs are below or around those considered safe. With respect to potential adverse health effects, a more dominant role of in utero exposure versus lactational exposure is indicated. If potential adverse effects are balanced against positive health aspects for (breastfed) infants, the advantages of breastfeeding far outweigh the possible disadvantages. Our observations provide a strong argument to plea for further global source-directed measures to reduce human exposure further to dioxin-like compounds.

The performance of atmospheric pressure gas chromatography-tandem mass spectrometry compared to gas chromatography-high resolution mass spectrometry for the analysis of polychlorinated dioxins and polychlorinated biphenyls in food and feed samples

Recently, gas chromatography tandem mass spectrometry (GC-MS/MS) has been added in European Union (EU) legislation as an alternative to magnetic sector high resolution mass spectrometry (HRMS) for the analysis of dioxins and dioxin like polychlorinated biphenyls (dl-PCB) in food and feed. In this study the performance of APGC-MS/MS compared to GC-HRMS is investigated and compared with EU legislation. The study includes the legislative parameters, relative intermediate precision standard deviation (S_Rw,rel), trueness, sensitivity, linear range and ion ratio tolerance. In addition, over 200 real samples of large variety and spanning several orders of magnitude in concentration were analyzed by both techniques and the selectivity was evaluated by comparing chromatograms. The S_Rw,rel and trueness were evaluated using (in-house) reference samples and fulfill to EU legislation, though the S_Rw,rel was better with GC-HRMS. The sensitivity was considerably better than of GC-HRMS while the linear range was similar. Ion ratios were mostly within the tolerable range of ±15%. A (temporary unresolved) systematic deviation in ion ratio was observed for several congeners, yet this did not lead to exceeding of the maximum ion ratio limits. The APGC-MS/MS results for the non-dioxin-like-PCBs (ndl-PCBs) were negatively biased, particularly for PCB138 and 153 in contaminated samples. The selectivity of APGC-MS/MS was lower for several matrices. Particularly for contaminated samples, interfering peaks were observed in the APGC chromatograms of the native compounds (dioxins) and labeled internal standards (PCBs). These can lead to biased results and ultimately to false positive samples. It was concluded that the determination of dioxins and PCBs using APGC-MS/MS meets the requirements set by the European Commission. However, due to generally better selectivity and S_Rw,rel, GC-HRMS is the preferred method for monitoring purposes.

Brominated flame retardants (BFRs) in breast milk and associated health risks to nursing infants in Northern Tanzania

The main aim of this study was to assess brominated flame retardants (BFRs) in breast milk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6-pentabromotoluene (PBT). The Ʃ7PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (<LOD) to 785ng/g lipid weight (lw). BDE 47, 99, 100 and 153 were the dominating congeners, suggesting recent and ongoing exposure to banned, commercial PentaBDE mixture. A multiple linear regression model revealed that mothers eating clay soil/Pemba during pregnancy had significantly higher levels of BDE 47, 99, 100 and 153 in their breast milk than mothers who did not eat clay soil/Pemba. Infant birth weight and birth length were significantly correlated with the levels of BDE 47, 99, 100 and 153. The estimated daily intake (ng/kg body weight/day) of BDE 47 and 99 exceeded the US EPA Reference doses (RfD) in four and eight mothers, respectively, suggesting a potential health risk to the nursing infants.

Determination of metal ion contents of two antiemetic clays use in Geophagy

Nausea is usually associated with early to late stages of pregnancy. Geophagy-deliberate consumption of soil is a common method of managing gravidae-induced discomfort. To control nausea, pregnant women in Nigeria commonly eat baked clay called "Eko" and another type of clay that induces buccal constriction called "Omumu". The metal contents in Eko and Omumu, digested under different pH conditions (acidic, alkaline and neutral), were investigated using Inductively Coupled Plasma Optical Emission Spectroscopy (ICPS-OES). We identified and quantitate the elements present and speculate on their potential impact on maternal and fetal health upon gestational exposure beyond the acceptable exposure levels and the Millennium Contaminant Level Goals (MCLG) set by the United States Environmental Protection Agency (USEPA). Specifically, our result indicates unacceptably high levels of aluminum in Eko and Omumu (>10-fold greater than the highest desirable levels set by the USEPA). The aluminum concentrations were influenced by the pH condition in which the samples were digested. Dietary exposure to aluminum at such high levels may be deleterious to maternal health and fetal development. Therefore consumption of Eko and Omumu as an antidote to reduce nausea during pregnancy should be discouraged. Future studies are planned to investigate specific impacts on fetal and maternal health and likely teratogenicity in rodent models.

Predictors of serum polychlorinated biphenyl concentrations in Anniston residents

The Anniston Community Health Survey was a community-based cross-sectional study of Anniston, Alabama, residents who live in close proximity to a former PCB production facility to identify factors associated with serum PCB levels. The survey comprises 765 Anniston residents who completed a questionnaire interview and provided a blood sample for analysis in 2005-2007. Several reports based on data from the Anniston survey have been previously published, including associations between PCB exposure and diabetes and blood pressure. In this study we examine demographic, behavioral, dietary, and occupational characteristics of Anniston survey participants as predictors of serum PCB concentrations. Of the 765 participants, 54% were White and 45% were African-American; the sample was predominantly female (70%), with a mean age of 55 years. Serum PCB concentrations varied widely between participants (range for sum of 35 PCBs: 0.11-170.4 ng/g wet weight). Linear regression models with stepwise selection were employed to examine factors associated with serum PCBs. Statistically significant positive associations were observed between serum PCB concentrations and age, race, residential variables, current smoking, and local fish consumption, as was a negative association with education level. Age and race were the most influential predictors of serum PCB levels. A small age by sex interaction was noted, indicating that the increase in PCB levels with age was steeper for women than for men. Significant interaction terms indicated that the associations between PCB levels and having ever eaten locally raised livestock and local clay were much stronger among African-Americans than among White participants. In summary, demographic variables and past consumption of locally produced foods were found to be the most important predictors of PCB concentrations in residents living in the vicinity of a former PCB manufacturing facility.

Combination of a fast cleanup procedure and a DR-CALUX® bioassay for dioxin surveillance in Taiwanese soils

Our goal was to determine dioxin levels in 800 soil samples collected from Taiwan. An in vitro DR-CALUX^® assay was carried out with the help of an automated Soxhlet system and fast cleanup column. The mean dioxin level of 800 soil samples was 36.0 pg-bioanalytical equivalents (BEQs)/g dry weight (d.w.). Soil dioxin-BEQs were higher in northern Taiwan (61.8 pg-BEQ/g d.w.) than in central, southern, and eastern Taiwan (22.2, 24.9, and 7.80 pg-BEQ/g d.w., respectively). Analysis of multiple linear regression models identified four major predictors of dioxin-BEQs including soil sampling location (β = 0.097, p < 0.001), land use (β = 0.065, p < 0.001), soil brightness (β = 0.170, p < 0.001), and soil moisture (β = 0.051, p = 0.020), with adjusted R² = 0.947 (p < 0.001) (n = 662). An univariate logistic regression analysis with the cut-off point of 33.4 pg-BEQ/g d.w. showed significant odds ratios (ORs) for soil sampling location (OR = 2.43, p < 0.001), land use (OR = 1.47, p < 0.001), and soil brightness (OR = 2.83, p = 0.009). In conclusion, four variables, including soil sampling location, land use, soil brightness, and soil moisture, may be related to soil-dioxin contamination. Soil samples collected in northern Taiwan, and especially in Bade City, soils near industrial areas, and soils with darker color may contain higher dioxin-BEQ levels.