Prostate cancer and toxicity from critical use exemptions of methyl bromide: Environmental protection helps protect against human health risks

Abstract

BackgroundAlthough ozone-depleting methyl bromide was destined for phase-out by 2005, it is still widely applied as a consequence of various critical-use-exemptions and mandatory international regulations aiming to restrict the spread of pests and alien species (e.g. in globalized transport and storage). The withdrawal of methyl bromide because of its environmental risk could fortuitously help in the containment of its human toxicity.MethodsWe performed a systematic review of the literature, including in vitro toxicological and epidemiological studies of occupational and community exposure to the halogenated hydrocarbon pesticide methyl bromide. We focused on toxic (especially chronic) or carcinogenic effects from the use of methyl bromide, on biomonitoring data and reference values. Eligible epidemiological studies were subjected to meta-analysis.ResultsOut of the 542 peer reviewed publications between 1990-2011, we found only 91 referring to toxicity of methyl bromide and 29 using the term "carcinogenic", "neoplastic" or "mutagenic". Several studies provide new additional data pertaining to the mechanistic aspects of methyl bromide toxicity. Few studies have performed a detailed exposure assessment including biomonitoring. Three evaluated epidemiological studies assessed a possible association between cancer and methyl bromide. Overall, exposure to methyl bromide is associated with an increased risk of prostate cancer OR, 1.21; 95% CI (0,98-1.49), P = 0.076. Two epidemiological studies have analyzed environmental, non-occupational exposure to methyl bromide providing evidence for its health risk to the general public. None of the epidemiological studies addressed its use as a fumigant in freight containers, although recent field and case reports do refer to its toxic effects associated with its use in shipping and storage.ConclusionsBoth the epidemiological evidence and toxicological data suggest a possible link between methyl bromide exposure and serious health problems, including prostate cancer risk from occupational and community exposure. The environmental risks of methyl bromide are not in doubt, but also its health risks, especially for genetically predisposed subjects, should not be underestimated.

Regulation and practice of workers’ protection from chemical exposures during container handling

“…Fumigation is a widely used method to prevent a multitude of pests, i.e. fungi and arthropods, from destroying natural products and spread worldwide during transport [2]. Previous studies in the harbours of Hamburg and Rotterdam have identified high frequencies of containers contaminated with fumigants and other industrial chemicals, such as methyl bromide and formaldehyde, the concentration of which in many cases exceeded the chronic recommended exposure levels [1,3].…”

“…The main targets of toxic effect are the respiratory and the nervous system. Ethylene oxide, formaldehyde and benzene can damage DNA and induce cancer as recognised by the International Agency for Research on Cancer, while some fumigants, such as methyl bromide, are suspected carcinogens [2,[13][14][15].…”

Addendum to Methyl bromide [BAT Value Documentation 2014]

“…As there is a lack of alternative and similarly cost-effective fumigants, numerous exemptions, especially in agriculture (Norman 2005) and in the transport industry (Budnik et al 2012), have been applied for.…”

“…Peak exposures and intoxication due to improper handling of the fumigant, often together with a lack of or inadequate protective clothing occur frequently. Increasingly there are also unexpected exposures in the transport sector, for example when handling or transshipping transport containers (Breeman 2009;Budnik et al 2012). …”

In-vitro Study of Anti-Fusarium Effect of Thymol, Carvacrol, Eugenol and Menthol

“…To control the Fusarium wilt, growers use systemic fungicides like methyl bromide [1], chloropicrin and benomyl [2]. Beside the fact that these chemicals are toxic to humans and the environment [3], they can also cause selection for resistant mutated pathogen [4].…”