Quantification of biologically effective environmental UV irradiance

Flexible and Ecological Cotton-Based Dosimeter for 2D UV Surface Dose Distribution Measurements

This work presents a 2D radiochromic dosimeter for ultraviolet (UV) radiation measurements, based on cotton fabric volume-modified with nitroblue tetrazolium chloride (NBT) as a radiation-sensitive compound. The developed dosimeter is flexible, which allows it to adapt to various shapes and show a color change from yellowish to purple-brown during irradiation. The intensity of the color change depends on the type of UV radiation and is the highest for UVC (253.7 nm). It has been shown that the developed dosimeters (i) can be used for UVC radiation dose measurements in the range of up to 10 J/cm2; (ii) can be measured in 2D using a flatbed scanner; and (iii) can have the obtained images after scanning be filtered with a medium filter to improve their quality by reducing noise from the fabric structure. The developed cotton-NBT dosimeters can measure UVC-absorbed radiation doses on objects of various shapes, and when combined with a dedicated computer software package and a data processing method, they form a comprehensive system for measuring dose distributions for objects with complex shapes. The developed system can also serve as a comprehensive method for assessing the quality and control of UV radiation sources used in various industrial processes.

Study of NBT-Pluronic F-127 Gels as 1D UV Radiation Dosimeters for Measurement of Artificial Light Sources

This work reports on radiochromic dosimeters for 1D UV light measurements. The dosimeter is composed of a 25% Pluronic F–127 that forms a physical gel matrix and nitro blue tetrazolium chloride (NBT) as a radiation-sensitive compound. This dosimeter was exposed to UVA, UVB and UVC radiation, and the radiochromic reactions were followed with reflectance spectrophotometry including changes in light reflectance and color coordinates in the CIELAB color system. The exposition of dosimeters to all UV radiation caused color changes from pale yellow to dark violet, and its intensity increased with increasing absorbed dose. The effects of NBT concentration and UV radiation type on the dose–response of the dosimeters were also examined. The results obtained reveal that the dosimeters are the least sensitive to irradiation with UVC and the most sensitive to irradiation with UVB (e.g., dosimeter with 2 g/dm³ of NBT was characterized by the following parameters: the threshold dose 0.1 J/cm²; the dose sensitivity −5.97 ± 0.69 cm²/J; the linear dose range 0.1–2.5 J/cm²; the dynamic dose range was equal to 0.1–3 J/cm²). The results obtained reveal that the NBT–Pluronic F–127 dosimeters can be potentially useful as 1D sensors for artificial UV radiation sources measurements.

Ground-based measurements of total ozone column amount with a multichannel moderate-bandwidth filter instrument at the Troll research station, Antarctica

Combining information from several channels of the Norwegian Institute for Air Research (NILU-UV) irradiance meter, one may determine the total ozone column (TOC) amount. A NILU-UV instrument has been deployed and operated on two locations at Troll research station in Jutulsessen, Queen Maud Land, Antarctica, for several years. The method used to determine the TOC amount is presented, and the derived TOC values are compared with those obtained from the Ozone Monitoring Instrument (OMI) located on NASA's AURA satellite. The findings show that the NILU-UV TOC amounts correlate well with the results of the OMI and that the NILU-UV instruments are suitable for monitoring the long-term change and development of the ozone hole. Because of the large footprint of OMI, NILU-UV is a more suitable instrument for local measurements.

Skin cancer and welding

Many workers in several different occupations can be exposed to ultraviolet radiation (UVR), which may increase their risk of developing skin cancer. Welding, an occupation employing an estimated 11 million people worldwide, is one such occupation. Welders are known to be exposed to the full spectrum of UVR from the welding arc and often experience burns and localized cutaneous erythema. In 2017, UVR from welding was classified as carcinogenic to humans based on sufficient evidence of ocular melanoma in humans. It has been hypothesized that exposure to UVR from the welding arc also may increase the risk of skin cancer among workers in this occupation. This review summarizes the current literature on skin cancer risk in welders.

Incidence of cutaneous malignant melanoma in Iranian provinces and American states matched on ultraviolet radiation exposure: an ecologic study

OBJECTIVES

Ultraviolet radiation (UVR), with UVB and UVA as the relevant components, is a risk factor for melanoma. Complete ascertainment and registration of melanoma in Iran was conducted in five provinces (Ardabil, Golestan, Mazandaran, Gilan and Kerman) during 1996-2000. The aim of our study was to compare population-based incidence data from these provinces with rates in the United States (US) while standardizing ambient UVR.

METHODS

Population-based rates representing all incident cases of melanoma (1996-2000) across the five Iranian provinces were compared to rates of melanoma among white non-Hispanics in the US. Overall age-standardized rates (ASR) for Iran and the US (per 100,000 person-years adjusted to 2000 world population) and standardized rate ratios (SRR) were calculated. We measured erythemally-weighted average solar UVR exposures (with contributions from both UVB and UVA range) of the five Iranian provinces using data from NASA's Total Ozone Mapping Spectrometer and selected five US states (Kentucky, Utah, Texas, Oklahoma, and Hawaii) with matching UVR exposure to each province. Incidence rates of melanoma during 1996-2000 in each Iranian province were compared to rates among white non-Hispanics in its UVR-matched US state.

RESULTS

The overall male and female ASRs of melanoma were 0.60 (95%CI: 0.56-0.64) and 0.46 (95%CI: 0.42-0.49), respectively, for Iran and 22.78 (95%CI: 22.42-23.14) and 16.61 (95%CI: 16.30-16.92) for the US. SRRs of melanoma comparing US to Iran were 37.97 (95%CI: 35.78-40.29) for males and 36.11 (95%CI: 33.69-38.70) for females, indicating significantly higher incidence in the US. ASRs and age-specific rates of melanoma for both genders were significantly lower in each Iranian province compared to its UVR-matched US state.

CONCLUSION

The markedly lower incidence rates of melanoma in Iranian provinces with similar UVR exposures to US states underscore the need for additional comparative studies to decipher the influence of other extrinsic and intrinsic factors on the risk of this malignancy.

Metal arc welding and the risk of skin cancer

OBJECTIVES

Arc welding produces the full spectrum of ultraviolet radiation and may be a contributory cause of skin cancer; however, there has been little research into this occupational hazard. The aim of this study is to explore if metal arc welding increases the risk of malignant melanoma and/or basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) on skin areas which may possibly be exposed (neck, head, and upper extremities).

METHOD

A Danish national company-based historic cohort of 4333 male metal arc welders was followed from 1987 through 2012 to identify the risk of skin cancer. An external reference group was established including all Danish skilled and unskilled male workers with similar age distribution. Occupational histories were gathered by questionnaires in 1986 and information about skin cancer diagnoses [BCC, SCC, cutaneous malignant melanoma (CMM), and precancerous conditions, actinic keratosis (AK)] were gathered from the Danish Cancer Registry supplemented by the data from the Danish Pathology Register. Hazard ratios (HRs) were calculated in the follow-up period from 1987 until 2012 using Cox regression analysis and adjusted for baseline data regarding age and social group.

RESULTS

The adjusted HR and 95% confidence interval (CI) for skin cancer (all types) were 0.99 (CI 0.94-1.04) for welders. The adjusted HR for AK and BCC located only at neck was 2.49 (CI 1.03-5.99) for welders exposed >20 years (n = 5) and 2.46 (CI 1.02-5.94), respectively, for welders exposed >30 years (n = 5). No statistically significant difference was observed for SCC. The risk of CMM at the neck was also significantly elevated after 30 years of welding, but this is based upon only one exposed case.

CONCLUSION

This study indicates that long-term exposure to metal arc welding may be related to increased risk of BCC and AK located exclusively at the neck. The study provides no support for the hypothesis that welding exposure increases the risk for skin cancer at other locations.

Analysis of gene regulation in rabbit corneal epithelial cells induced by ultraviolet radiation

Ultraviolet (UV)-induced cataracts are becoming a major environmental health concern because of the possible decrease in the stratospheric ozone layer. Experiments were designed to isolate gene(s) affected by UV irradiation in rabbit cornea tissues using fluorescent differential display-reverse transcription-polymerase chain reaction (FDDRT-PCR). The epithelial cells were grown in standard medium for 2 or 4 hours post treatment. Cornea epithelial cells were irradiated with UVB for 20 minutes. RNA was extracted and amplified by reverse transcriptase-polymerase chain reaction using poly A+ specific anchoring primers and random arbitrary primers. Polyacrylamide gel electrophoresis revealed several differentially expressed genes in untreated versus UV irradiated cells. Complimentary DNA (cDNA) fragments resulting from fluorescent differentially expressed mRNAs were eluted from the gel and re-amplified. The re-amplified PCR products were cloned directly into the PCR-TRAP cloning system. These data showed that FDDRT-PCR is a useful technique to elucidate UV-regulated gene expressions. Future experiments will involve sequence analysis of cloned inserts. The identification of these genes through sequence analysis could lead to a better understanding of cataract formation via DNA damage and mechanisms of prevention.

Ultraviolet radiation from welding and possible risk of skin and ocular malignancy

Arc welding produces the full spectrum of ultraviolet radiation (UVR). It is possible that welders are at greater risk of developing skin cancer than the general population, but there is a dearth of well designed studies in this area. The only major study of the relationship between arc welding and skin cancer risk did not reveal an increased incidence of skin cancer in welders. As the welders examined were all well protected and the length-of-exposure period was limited, the findings cannot be generalised to all welders. Studies have demonstrated that welding increases the risk of ocular melanoma. Just as we urge the public to protect themselves from UVR, we need to consider similar advice for arc welders.