Persistent Organic Pollutants
Over the past few years, research into the link between environmental chemicals and health problems has increased, with results suggesting that exposure to such toxic chemicals and persistent organic pollutants is causing widespread health and environmental problems.
What are Persistent Organic Pollutants (POPs)?
The term ‘Persistent Organic Pollutants’ (POPs) refers to a group of several hundred toxic environmental chemicals found in industrialised and non-industrialised regions. Chemicals include pesticides, solvents, flame-retardants and pharmaceuticals that humans and animals are exposed to on a regular basis.
POPs are referred to as ‘persistent’ because they are stable and resist decomposition and degradation via chemical, photolytic and biological processes. This allows them to accumulate, which they do in the fatty tissue of those exposed to them, with higher levels found in creatures towards the top of the food chain. They also have the ability to travel in the form of vapours in the atmosphere, or attached to the surface of solid particles. Their impact is therefore extensive and widespread, reaching areas far from the place they were originally emitted to a new site where they may have never been used, and the disruptive impact lingers long after their use has been stopped.
How are we exposed to POPs?
Humans are exposed to POPs during foetal development in the womb and after birth through breast milk. Most exposure then comes through diet in the form of pesticides, insecticides and fungicides that are sprayed onto food, plastics we wrap and store food and beverages in, as well as through the ingestion of animals and seafood containing POPs in their fatty tissue. Some POPs are found in cosmetics and medications, plus in the workplace where chemicals, solvents and combustion byproducts, such as dioxins, are used.
How do POPs impact health?
Many of the adverse health problems associated with POPs relate to their ability to disrupt the endocrine system. They do so by mimicking the naturally occurring hormone, and binding to a cell receptor, which prevents the naturally occurring hormone from binding instead. In 2000, an independent panel of experts found credible evidence to suggest that such hormone-like chemicals negatively impacted the test-animal’s bodies at exposure levels well below those thought to produce no effect in traditional testing. Such chronic, low-level exposure, typically starting in utero, has been linked to numerous health problems including reduced fertility, plus an increase in conditions such as diabetes, obesity, cancer, immune system dysregulation and cardiovascular disease.
- Diabetes – POP exposure has been linked in human and animal studies to an increase incidence of Type 2 diabetes, in particular chlorinated POPs such as dioxins and HCB (hexachlorobenzene). A study in 2006 found that the higher the level of exposure, the higher the incidence of diabetes, with a 37.7% increased risk in the highest group compared to those with the lowest level of exposure.
- Obesity – while results are mixed, some research studies have found a link between POP exposure and increased body mass index, and subsequent development of abdominal obesity after POP exposure. Babies and children are also affected in this way, with numerous studies linking POP exposure in the womb to a higher BMI in childhood and later life.
- Cancer – findings from studies on exposure to POPs and cancer are unclear. While research into TCDD has found it to be carcinogenic, especially in large accidental doses, the relationship between cancer and other POPs such as dioxins and PCBs is less clear, although the increasing incidence of Non-Hodgkin’s lymphomas, considered to be a likely consequence of POPs, may suggest a link.
- Immune system – it is thought that POPs enter the body, bypassing the mucosal barriers, and interact with the immune system. This may begin early in life and could contribute to the disruption of the normal functioning of the immune system, including a decreased ability to fight infection, as well as increased inflammation and immune activity contributing to autoimmunity and allergy.
- Foetal growth and development – numerous studies have found a link between POP exposure in the womb, notably DDE, HCB and PCB, and reduced foetal growth and lower birth weights. Additionally, a Dutch study of children found that their exposure in utero to ‘normal’ levels of PCBs and Dioxins resulted in poorer cognitive functioning.
- Cardiovascular disease – research has found PCB present in lipoproteins (LDL and VLDL), with higher levels in those suffering from cardiovascular disease compared to controls, and associated impairment of HDL to protect against oxidation.
How do we know if we have an issue with POPs?
We can test for these in a simple urine test and also look at liver enzymes. A clinical pearl is a GGT over 50 will often mean that POPS are an issue.
How do we get rid of POPs from the body?
These can be ridden from the body using certain detoxification techniques and finding the source of exposure. The detoxification method will depend on the type of POP that is an issue.
Written by Emma Rushe