Radiation literature survey

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This study examined the effects radiofrequency electromagnetic fields (RF EMF) had on mice sperm. Mice received a whole-body RF exposure at 905 MHz with a specific absorption rate (SAR) of 2.2 W/Kg 12 hours a day for 1, 3 or 5 weeks. The study reported statistically significant decreases in sperm vitality and motility. Further, the study reported statistically significant increases in sperm mitochondrial reactive oxygen species and oxidative DNA damage. There were no changes reported in the fertility of the RF EMF treated mice. The authors concluded that sustained whole-body RF EMF is capable of inducing oxidative damage in sperm DNA.

Whole-body exposures to radiofrequency-electromagnetic energy can cause DNA damage in mouse spermatozoa via an oxidative mechanism

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This study exposed mice to very high levels of RF EMF. The public whole-body average SAR limit is 0.08 W/kg. This means the study exposed these mice to RF EMF that was over 27 times higher than the human public exposure limit. The study did not investigate the effect of heat stress or measure the temperature of the exposed mice. Another study investigating the effect of heat stress on fertility of mice reported similar results on sperm (Pérez‐Crespo et al, 2008). This indicates that the reported results likely occurred as a result of heating rather than being a sub-thermal effect. The ARPANSA radiofrequency exposure standard RPS3 gives limits for exposure that protect against any known biological effects. The only established effect of exposure is heating of biological tissue. The limits set for both public and occupational exposure are many times below the level where any measurable heating occurs, ensuring a large degree of conservatism within the standard.

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This population-based case-control study compared mobile phone use with the incidence of thyroid cancer diagnosed between 2010 and 2011 in Connecticut. The study included 440 cases of histologically confirmed incident thyroid cancers and 460 controls, with genotyping information for 823 single nucleotide polymorphisms (SNPs) in 176 DNA genes. All participants, including cases and controls, were interviewed using a standardized questionnaire to collect information on mobile phone use and the responses were used to classify cases and controls as users or non-users. Blood samples were provided for DNA analysis. The authors reported that the study found a statistically significant association between cell phone use and thyroid cancer for certain SNPs, implying a genetic susceptibility to thyroid cancer due to mobile phone use.

Genetic susceptibility may modify the association between cell phone use and thyroid cancer: A population-based case-control study in Connecticut

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This study built upon a previous study by the same authors (Lou et al, 2019) that found no association between mobile phone use and thyroid cancer in the same study group. One of the advantages of using a study group within the period 2010-2011 was that it is much easier to separate mobile phone users from non-mobile phone users. A disadvantage of using this study group was that the exposure data had to be gathered through surveying the participants. The information required was from a point in the distant past where recall bias may effect some of the results. The control group consisted of a higher proportion of males to females than the case group. This may have significant implications on the reliability of the results due to the higher occurrence of thyroid cancer in of woman. Further, mobile phones were not the only exposures to radio waves during the time of exposure assessment. A good example of this was the widespread use of cordless phones which are used in the same manner (held to the head) and have a similar level of exposure.

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The French Agency for Food, Environmental and Occupational Health & Safety (ANSES) produced a report assessing the risks associated with the use of Light Emitting Diodes (LEDs). The report also provided recommendations aimed at better protection of human health and the environment. LED lighting can be found in all aspects of modern society including personal devices with visual displays (e.g. phones and tablets), toys, car lights and outdoor and house lighting systems. The ANSES assessed evidence of whether the blue light content and temporal light modulation (flickering) properties of LEDs could increase the risk of potential health effects of this lighting source. The opinion focused on the major risks to human health and biodiversity of fauna and flora. 

The report concluded that there was some evidence that LEDs, particularly types rich in blue light, may affect both circadian rhythm and diseases of the eye. However, this evidence is not strong enough to calculate the level of risk. Little research has been done on the effects of modulation and there is limited evidence of symptoms such as migraines and epileptic attacks. The research on biodiversity was limited and relied on studies of all artificial lighting, not specifically LEDs. There was some evidence that lighting could affect biodiversity, however, it was not clear to what extent lighting is associated with any reported effects, with other important confounding factors such as pollution, habitat reduction, climate change and environmental overexploitation needing to be considered.

ANSES opinion on the potential risk of LEDs on the health of humans and fauna and flora

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While there is research showing potential health effects of exposure to LED lighting, it is not clear if the impacts are from the effect of exposure to the light or other factors. This is particularly evident with the potential impact of blue light on the circadian rhythm. Research indicates that blue light exposure from phones and tablets in the evening can affect sleep quality; however, it is not clear if this is a result of the activity being carried out or the blue light exposure. The Scientific Committee on Health, Environmental and Emerging Risks (SCHEER, 2018) had recently reviewed the evidence on the effects of LEDs on human health. ARAPNSA also reviewed the SCHEER opinion as part of our radiation literature survey in 2018. SCHEER concluded that the available scientific research does not support an association between LEDs and a health risk to the eye or skin. However, in common with the ANSES report, disruption to circadian rhythm was identified as a potential effect. Distraction and other optical phenomena (e.g. phantom array effect) from LEDs incorporating temporal light modulation was also identified as an indirect risk factor for harm in both the ANSES and SCHEER reports.

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This was a retrospective cohort study that examined the association between ultraviolet radiation (UVR) and basal cell carcinoma (BCC) The study followed 63,912 white cancer-free US radiologic technologists with known ultraviolet exposure (irradiance at up to 5 residential locations) for 5–22 years. 2151 technologists reported incident primary BCC within the study period. The authors reported that the absolute risk of BCC increased with increased cumulative UVR exposure. The authors also reported that the relative risk showed substantial variation with time after exposure and age at exposure, so that risk is highest for the period 10–14 years after UVR exposure and for those exposed under the age of 25. Some limitations described by the authors in the study included that the BCC incidence was self-reported, however, a large number of these were verified through medical records. Also, residency used for exposure assessment was self-reported. Assumptions were made that this cohort of workers spent a large proportion of their time indoors due to their profession and could not take into account individual behaviour such as excessive outdoor activity and UVR exposure received on holidays.

US study adds weight to increased risk of basal cell skin cancer from exposure to solar UV radiation

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Despite some of the limitations described by the authors, this study added to the body of evidence that UVR exposure is a causal factor in the development of BCC. Evidence for the association between UVR exposure and the development of other skin cancer types such as squamous cell carcinoma and melanoma has been clearer in the body of scientific evidence. This large study strengthens the evidence of an increase in BBC with increasing cumulative UVR exposure. The results support the advice from both ARPANSA and Cancer Council Australia about limiting UV exposure and applying sun protection measures.

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This meta-analysis examined 225 studies consisting of human, cellular and animal experiments specifically focussing on genetic damage from exposure to radiofrequency (RF) electromagnetic energy. The meta-analysis assessed the quality of the studies by the presence or absence of four different parameters; blinding, adequately described dosimetry, positive controls and sham-exposed controls. The authors compared the reported results of each study against the assessed level of quality of these factors within the study. It was reported that studies with a high degree of quality in these parameters reported fewer, if any, effects from exposure to radio waves. Further, the authors observed that studies that reported no significant change in genetic damage of cells exposed to RF incorporated more quality control parameters into their experiments. Conversely, studies that reported increased damage in cells exposed to RF used fewer quality control parameters. The authors concluded that the use of quality control measures within experimental design are extremely important in order to provide a meaningful evaluation of any potential health risk from RF exposure.

Comprehensive Review of Quality of Publications and Meta-analysis of Genetic Damage in Mammalian Cells Exposed to Non-Ionizing Radiofrequency Fields

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This meta-analysis demonstrates the importance of evaluating evidence based on the quality of the methods used in studies while considering the reported biological and health effects.  This underlying principle of evidence evaluation to assess its strength is particularly topical with the current roll-out of the next generation of mobile telecommunications technology, 5G. Exposure to RF remains one of the most high profile public health concerns and also one of the most highly researched environmental agents in biomedical research. ARPANSA’s RF exposure standard sets limits based on the body of scientific evidence available and is designed to protect against the known harmful effects of RF exposure. The study by Vijayalaxmi and Prihoda TJ demonstrates the considerations the scientific community make when assessing the evidence for harm from exposure to RF. ARPANSA and other bodies such as the World Health Organisation and the International Commission on Non-ionzing Radiation Protection consider all studies in the assessment of their health advice concerning RF exposure. There is also an ARPANSA factsheet about how we assess scientific evidence (link). Based on evaluations for these organisations, and consistent with the conclusions of Vijayalaxmi et al, there is no established evidence of harmful effects from exposure to low-level RF exposure below the limits in the ARPANSA standard.

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This survey that examined the occurrence of eye injuries caused by hand held lasers in Canada. Questionnaires developed by Health Canada were sent to optometrists and ophthalmologists surveying the cases of eye injuries from hand held lasers. Responses from the survey indicated that there were 318 eye injuries caused by hand held lasers between 2014 and 2017. Of these injuries, 77 were minor to severe cases of vision loss and 59 were classified as retinal damage. There was a higher prevalence of eye injuries for males (82.5%) than females (14.0%). Injuries were also reported to occur more often due to the actions of another person (67.6%) rather than self-exposure (26.1%). The authors concluded that the results provided insights into the potential prevalence of injuries from exposures to handheld laser devices in Canada. However, these results were not nationally representative due to the low survey response rate (23.1% and 12.7% for optometrists and ophthalmologists, respectively) and other unknown factors. These included potential over-reporting by duplication from the two responding professional groups, eye injuries from other causes and reported exposures not leading to injuries.

Survey of reported eye injuries from handheld laser devices in Canada

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In Australia, all hand held laser pointers available to the public are restricted to an accessible emission limit (AEL) of a Class 2 laser. This means they must have a power output of less than 1 milliwatt (mW). Lasers with an output below this limit are considered a low hazard. Unfortunately, Australian studies have shown that handheld laser pointers available to the public are not always labelled correctly and may emit energy at harmful levels. In one study, the majority of laser pointers tested failed to meet the output restriction with outputs well above 1 mW. (Wheatley, 2013). ARPANSA provides advice on laser safety on its website to promote risk awareness and assist in responsible use of handheld laser products (link).

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This study, by Smith-Roe et al, is part of the National Toxicology Program’s (NTP) investigation of the effects radio waves, also called radiofrequency electromagnetic fields, have on rats and mice. This study examined possible genotoxic effects on a separate sample of rats and mice that were exposed for a shorter time period as part of the NTP study. The animals were exposed to radio waves at certain frequencies used by mobile phone networks (CDMA or GSM) for 9 hours a day at levels of up to 10 watts per kilogram (W/kg) over a period of up to 19 weeks. The study specifically reported on DNA damage within the tissues of the animals examined. The authors reported a statistically significant increase in levels of DNA damage in the frontal cortex of male rats and mice and in the hippocampus of male rats. Only the CDMA-modulated exposed rats had statistically significant levels of DNA damage for both tissue regions. Further, the study concluded there was variable levels of DNA damage observed. Overall, for female rats and mice, the study did not report any consistent statistically significant results.

Evaluation of the genotoxicity of cell phone radiofrequency radiation in male and female rats and mice following subchronic exposure.

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In 2018, the NTP released their final reports, which investigated whether exposure to radio waves causes any health effects, including cancer, in rats and mice. An assessment of the results from the NTP study reports in their entirety have previously been provided by ARPANSA and the International Commission on Non-ionizing Radiation Protection (ICNIRP). 

The study by Smith-Roe et al reports certain genotoxic effects related to radio waves at very high exposure levels, however the effects were inconsistent across rats and mice, males and females, and type of radio wave exposure (GSM or CDMA). There is no explanation for these variations in the results across species, gender and type of radio waves. 

It is possible that that the reported effects occurred due to the high exposure levels. It is known that exposure to sufficiently high level radio waves can heat biological tissue and potentially cause tissue damage. It is also possible that the reported effects occurred due to chance. This is because the study conducted a number of different tests and, statistically, a positive result is always possible with multiple tests. This is often called the multiple comparisons or multiple testing problem.

In Australia, the safety standard for radio waves developed by ARPANSA sets mobile phone limits at 0.08W/kg for whole body and 2 W/kg for localised exposure. Most mobile phones produce exposures well below the limit. This makes it difficult to relate the high radio wave exposures of the animals in this study to the much lower exposure when people are using mobile phones. There have been many proposals for how radio waves, below the current exposure limits, could induce DNA damage in cells, however, there remains no proven mechanism for this effect or consistent results to confirm that it occurs. Overall, the study by Smith-Roe et al does not demonstrate consistent DNA damage across species, genders, or for types of radio waves and this could indicate that there is no common mechanism causing DNA damage (Fedak, 2015). 

ARPANSA‘s safety standard is based on scientific research that shows the levels at which harmful effects occur and it sets limits, based on international guidelines, well below these harmful levels to provide a high level of protection to the public. Overall, the limitations in the results by Smith-Roe et al do not provide sufficient evidence to justify a change in the current safety limits for radio wave exposures set within the standard. 
 

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This is a measurement study of radiofrequency (RF) electromagnetic field (EMF) exposure around small cell base station sites. With the proliferation of new mobile technology to meet increased demand, small cells play an important role in high density urban areas. The paper reported that measurements were conducted at 295 positions around 98 small cell sites in South Africa, the Netherlands and Italy. The measured exposure levels were then compared with exposure guidelines set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the results of other EMF surveys. The maximum EMF exposure recorded was less than 4% of the ICNIRP general public limit. These results were in agreement with other surveys.

Measurement of EMF exposure around small cell base station sites

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ARPANSA has conducted similar measurements around macro mobile phone base stations and published the results on the ARPANSA website. In 2017, ARPANSA published a study assessing the RF EMF exposure level due to Wi-Fi in Australian schools. Exposure levels from other RF sources such as mobile phone base stations, radio, and TV broadcasts were also measured. Overall, the exposure levels from all RF sources measured were much lower than the public exposure limits in the Australian RF standard.

This exposure study by Wyk et al. is one of few studies that have been performed around small cell base station sites. These sites are predominantly deployed inside shopping centres, on street lamp posts, bus stops etc. which improves capacity and coverage. As the small cell sites are widely visible and closer to sensitive areas, there has been increased concern from the general public regarding the EMF exposure from these sites, which this study has attempted to address. Small cell sites, which transmit less power have also been proposed as a possible replacement for macro base stations in future 5G network infrastructure, which will require a high base station density. Overall, the paper reported that the measured exposure levels were much lower than the Australian and international general public exposure limits.

Finally, it is noted that an internationally approved measurement protocol was used in this study and the measurements were conducted during the busiest time of the day while steps were taken to minimise interference to the measurement instruments.
 

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Summary:

This was a cohort study investigating the incidence of cancer among 83,284 UK electricity generation and transmission workers from 1973 to 2015. Electricity generation and transmission workers are often exposed to higher than normal levels of extremely low frequency (ELF) electric and magnetic fields (EMF) The study found statistically significant increases in the occurrence of mesothelioma and skin cancer and a statistically significant decrease in the occurrence of lung cancer. The author indicated that the increase in mesothelioma and skin cancer in the cohort could be explained by the past use of asbestos in the industry and the prevalence of outdoor work, respectively. Further, the author speculated that the reduction in lung cancer was due to a decrease of smokers in the industry; however, there was no smoking data collected from the cohort. The author concluded that the results support the need for protection of workers from asbestos and solar UV exposure. Further, the author states that the results suggest that the current protections for EMF exposure are adequate.  

Cancer incidence in UK electricity generation and transmission workers, 1973–2015

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There have been numerous previous studies that have investigated whether occupational exposure to ELF EMF causes cancer and especially breast cancer. In 2007, the World Health Organisation (WHO) reviewed in detail the risk of cancer from occupational exposure to ELF EMF. The review concluded no established evidence between occupational ELF EMF exposure and breast cancer or other cancers. This conclusion from WHO is in agreement with outcomes from the UK electricity generation and transmission workers cohort with Sorahan stating that of the 11 papers that have been previously published on this cohort no convincing links between magnetic fields and the examined health outcomes have been found. Two Australian studies by Karipidis et al (2007a and 2007b) reported no increased risk of glioma or non-Hodgkin lymphoma from workers exposed to ELF EMF. 

The current study by Sorahan also showed the importance of protecting workers from the harmful effects of the sun. Australia has one of the highest rates of skin cancer. Two in three Australians will be diagnosed with skin cancer by the age of 70 and more than 2000 Australians die from skin cancer each year (Cancer Council Australia, 2019). Occupational exposure can significantly contribute to these rates with a meta-analysis by Schmitt et al 2011 finding that people who were occupationally exposed to UV had an increased risk of squamous cell carcinoma. To protect workers from the consequences of high UV exposure, each Australian State or Territory has an occupational health and safety act that sets requirements for the protection of outdoor workers from solar UV. 

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The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO) and is responsible for assessing and classifying agents for their potential to cause cancer in humans. Initially, IARC was formed to classify the carcinogenicity of chemicals; however, the scope has since broadened to other agents including complex mixtures, physical agents (which includes radiation), biological organisms, pharmaceuticals, and other exposures. Expert working groups are set up to examine and classify the cancer risk of the agents being assessed. A preamble outlines the requirements of the identification, assessment and classification process. The preamble describes how a working group should gather and assess the evidence of carcinogenicity of the agent being considered and the role of the participants. Further, the preamble is also designed to promote transparency surrounding the evaluation process so the scientific community and the public can understand the decision of the working group.

The first part of the preamble characterises the exposure to the agent including descriptions of the physical quantities of the agent and the exposure scenarios in the environment. This part also includes a discussion of current regulations and a critical review of the exposure assessment in key epidemiological studies. There are three major categories used to examine the evidence of carcinogenicity. These categories include:

• carcinogenicity in humans
• carcinogenicity in experimental animals
• mechanistic evidence

A working group aims to thoroughly research and evaluate the available evidence of cancer risk from an agent within these categories.  

The final section of the preamble is an overall evaluation that discusses the evidence assessed and places the agent in set risk categories. The risk categories currently include:

• Group 1 - the agent is carcinogenic to humans
• Group 2A -the agent is probably carcinogenic to humans
• Group 2B - the agent is possibly carcinogenic to humans 
• Group 3 -the agent is not classifiable as to its carcinogenicity to humans

Recently IARC have updated the preamble for classifying carcinogenicity (IARC, 2019). The evaluation process in the reviewed 2019 IARC preamble has some key changes to its last revision in 2006 (IARC, 2006). One key change to the preamble is a strengthening of the evaluation process to make it more prescribed, for example, assessing the quality of the studies has been broken into seven well-described parts. This refining of the assessment methodology should increase the consistency and transparency of the evaluation process. Another key change is the addition of a table by Smith et al, 2016 describing key characteristics of an established carcinogen that can be used to help evaluate the mechanistic evidence. A small change was the removal of the group 4 classification, which was used to classify an agent as probably not carcinogenic to humans. This implies that IARC classifications now only include agents that have been confirmed as carcinogenic or display varying degrees of evidence and are still being assessed.

IARC has to date classified the carcinogenicity of over a thousand agents. The identification of an agent as carcinogenic may have a significant impact on society or the processes that result in exposure to the agent. Further, IARC’s classification does not include an assessment of exposure levels. Consequently, there is no consideration of dose or exposure level to which an agent begins to be carcinogenic. Therefore, the assessment is limited to whether the agent is or is not carcinogenic. This means that, with the appropriate control mechanisms, exposure to an agent may be possible with minimal risk of harm.

In 2013, IARC examined the evidence of carcinogenesis from radiofrequency electromagnetic fields. The results of the assessment were published in the IARC monograph “Non-ionising Radiation Part 2: radiofrequency electromagnetic fields Volume 102”. The overall evaluation found that radiofrequency electromagnetic fields are possibly carcinogenic to humans (Group 2B). This decision was based on limited evidence from epidemiological studies, which showed an increased risk of brain tumours among heavy mobile phone users. IARC noted at the time of the decision that the occupational and environmental exposures provided inadequate evidence of a cancer risk.

Periodically an IARC advisory group meet to make recommendations for what agents should be evaluated or re-examined for their carcinogenicity. In March 2019, recommendations for evaluations to be conducted in the 2020-2024 period were published in the Lancet Oncology journal. The list of recommendations included a re-assessment of radiofrequency electromagnetic fields (IARC, 2019). The rational for this re-evaluation was stated by IARC to be new bioassay and mechanistic evidence.

IARC Monographs Preamble

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ARPANSA fully supports the work of IARC and the revision of its preamble as it increases the transparency of the scientific evaluation process.