Alberta Biomonitoring Program
Alberta Biomonitoring Program
The Alberta Biomonitoring Program, measures the levels of environmental chemicals and substances in people living in Alberta. Overall, the objective of the program is to establish a baseline level of exposure to a variety of environmental chemicals in pregnant women, their developing infants, children, and the population in general.
The overall objective of the program is to establish a baseline level of exposure to a variety of environmental chemicals in vulnerable populations including pregnant women, their developing fetus, newborns, and children.
The phases of the program have received ethics approval through the Conjoint Health Research Ethics Board at the University of Calgary and/or the Health Research Ethics Board at the University of Alberta, in addition to other ethics boards depending on the phase
Why biomonitoring?
Humans often come into contact with chemicals of both natural and synthetic origin in the environment. Routes of exposure to these chemicals include inhalation, ingestion, and dermal contact with air, water, soil, food, and consumer products. The human health risks posed by exposure to a chemical are a function of the inherent toxicity of the chemical, how long one is exposed to the chemical, and how much of the chemical gets absorbed into the body, which is known as the internal dose. Any chemical has the potential to cause negative health effects if the dose is high enough. In other words, the dose makes the poison. The internal dose is difficult to predict because it is affected by both environmental variables and variations in human physiology and behaviour. The most accurate way to determine internal dose is to measure the concentration of the chemical of interest in relevant human samples such as blood, urine, and hair. This measurement is known as biomonitoring.
Researchers
Research partners:
• University of Calgary
• University of Alberta
• Alberta Health
• Alberta Health Services
• ALS Environmental
Project phases
The developing fetus is considered the most sensitive life stage and can be exposed to chemicals that cross the placenta. Maternal body burdens of some chemicals are known to cause adverse effects on fetal development, whereas the effects of emerging chemicals on fetal development are not as well understood. There may also be maternal complications because of the body being in a more physiologically stressed state, and therefore, more susceptible to negative effects of exposure to some environmental chemicals. In the early 2000s, a multi-disciplinary team of academic and professional experts collaborated to examine environmental chemical exposures in pregnant women in Alberta. At the time of this study, no systematic biomonitoring programs existed in Canada at either a national or provincial level. Therefore, the Phase One biomonitoring results represented the first comprehensive set of exposures in an Albertan population to legacy and emerging chemicals that may be present in food, water, soil, air, dust, or consumer products. The influence of maternal age, geographic location, and seasonality on these exposures was examined. All analyses were performed on pooled serum samples: individual prenatal serum samples remaining after infectious disease screening at the Alberta Precision Laboratory – Public Health laboratory (ProvLab) in Edmonton were pooled according to maternal age, geography, and season. Only the pools were analyzed; therefore, no individual results were presented.
Some of the highlights from this phase include:
- The main metabolite of nicotine (cotinine) was detected in pregnant women of all ages and from all regions. Concentrations were higher in younger women and in those from northern Alberta than southern Alberta.
- The only chemical that showed a consistent seasonal trend in concentration was lead, which displayed higher concentrations in all age groups in January and in the youngest age group in July.
- The use of pooled serum samples allowed for high enough detection rates to examine trends in concentration by age and geography for persistent organic pollutants such as organochlorine pesticides, polychlorinated biphenyls, and dioxins and furans.
If a chemical exposure is detected, it does not necessarily mean the exposure will result in a negative health effect.
Biomonitoring results from adults cannot be directly extrapolated to children. Children are not little adults and can have different and sometimes unique exposures to environmental chemicals. For example, children are closer to the ground and have more hand-to-mouth activity than adults, which can result in greater ingestion of dust and soil and, therefore, greater exposure to chemicals found therein. Children are in a developmental stage of life and because of their physiology they may have higher exposures to some chemicals. These chemicals may be handled differently by their immature set of systems when compared to an adult. These developmental windows are critical periods of vulnerability that create unique risks for children exposed to environmental chemicals. The purpose of Phase Two of the Alberta Biomonitoring Program was to determine the magnitude of the exposure of children living in Alberta to a similar set of environmental chemicals as was measured in pregnant women in Phase One. Neither Canada nor Alberta had monitored environmental chemicals in the blood of children in a systematic manner. Phase Two was one of the most extensive biomonitoring surveys at the time for a comprehensive set of legacy and emerging chemicals in children’s serum. The influence of age was examined for two age groups in southern Alberta. When possible, the concentrations of chemicals in the children were compared to those in the pregnant women from southern Alberta (Phase One). All analyses were performed on pooled serum samples: individual children’s serum samples were pooled according to age and only the pools were analyzed. The serum was archived at the Alberta Children’s Hospital and was originally drawn from healthy children presenting for elective surgeries. No individual results were presented. Some highlights from Phase Two include:
- Concentrations of the environmental chemicals were either lower or similar to concentrations reported in other studies of children in North America or around the world.
- The majority of the chemical concentrations did not differ significantly with the age of the children.
- Cotinine, the major metabolite of nicotine, was significantly lower in children than in the pregnant women (Phase One).
- Children had higher exposure than pregnant women to perfluoroalkyl substances, bisphenol A, 2,4-D, and trans-DCCA.
If a chemical exposure is detected, it does not necessarily mean the exposure will result in a negative health effect.
Fetal exposure to environmental chemicals takes place through the placenta. The placenta plays a protective role as a barrier that transfers selective antibodies, filters out certain agents, and metabolizes xenobiotics. Persistent organic pollutants have been reported to penetrate the fetal system, despite the protective role of the placenta. The fetal effects of many chemicals that cross the placenta are unknown, especially at low levels of exposure. Exposure to the fetus is a special case because of potentially enhanced vulnerability to toxic insults due to susceptibility during organogenesis and the development of metabolic systems. Phase Three of the Alberta Biomonitoring Program was designed to establish the magnitude of pregnant women’s exposure to environmental chemicals in seven regions of Alberta and compare this to the fetal exposure. A similar suite of chemicals to Phases One and Two were monitored, with the addition of phthalate metabolites and parabens. This was the first phase to use active recruitment to obtain samples, rather than using archived samples. The serum samples were placed into paired maternal and cord blood serum pools and stratified by maternal age and geographic region to evaluate the effect of these stratifications on exposure. The exposure differences between the maternal and cord pools were also investigated as were temporal trends in the exposure of pregnant women to chemicals monitored in both Phase One and Phase Three. No individual samples were analyzed. Some highlights from Phase Three include:
- Active recruitment allowed for more control over the material and supplies used for blood collection and storage.
- Many PCBs, organochlorine pesticides, PBDEs, PFAS, dioxins and furans, and BPA had higher mean concentrations in maternal than cord serum pools.
- Mean concentrations of two parabens, a phthalate metabolite, and six metals were higher in cord serum than maternal pools.
- The mean concentrations of many PFAS and PBDEs were lower in maternal serum pools in Phase Three (2013-2016) compared to Phase One (2005), highlighting a decrease over time as more regulations were put in place related to the use of some of these chemicals.
The first three phases of the Alberta Biomonitoring Program were surveillance style studies, examining exposures to large suites of environmental chemicals. Phase Four used a targeted approach to investigate the effect of the federal legalization of cannabis on exposure to cannabis, tobacco, and alcohol in pregnant women in Alberta. If pregnant women are using one substance, there is a risk they may be using more than one. The use of cannabis during pregnancy is associated with various adverse health outcomes such as low birth weight, early labour, and placental abruption. Tobacco smoking can elevate these risks. The exposure of the fetus to alcohol can result in physical and behavioural effects including facial deformities, kidney, heart, and bone problems, intellectual disabilities, and social difficulties. Concentrations of cannabis, tobacco, and alcohol biomarkers in the serum of pregnant women were measured. The serum samples were drawn from individual serum samples remaining at ProvLab in Edmonton following infectious disease screening. Samples were sequestered from before federal legalization of cannabis on October 17, 2018 (pre-legalization) and after (post-legalization). These samples were then pooled by maternal age, geographic region, and legalization status. No individual samples were analyzed. Some highlights from Phase Four include:
- Higher cannabis biomarker concentrations were noted in the youngest age group in both the pre-and post-legalization pools from most geographic regions
- Tobacco biomarker concentrations were higher in the pre-legalization pools than the post-legalization pools
- Alcohol biomarkers were detected in too few pools to calculate mean concentrations
- The cannabis and tobacco biomarkers chosen for analysis highlight the usage of these substances in the pregnant women sampled
