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Feature Sick Work! Sewage Exposure Stats And Solutions Everyone knows that sewer work is a "dirty job," but there are factors — and real-life stories — that suggest the incidence and risk of sickness are rising. By Kevin Westerling B edpan contents from quarantined hospital patients, radioactive chemicals, industrial chemicals, human blood from morgues, animal blood from labs — it all ends up in the sewer. Then, of course, there's the usual: anything and everything that goes down the toilet or drainpipe. Sewer workers are a hardy breed, and they know full well that they're dealing with some pretty gross … um, stuff. It may be an unwelcome surprise, however, to learn that the "stuff" they encounter is becoming increasingly pathogenic, and that the job is getting ever more dangerous. Viruses Trending Up There are approximately 3,000 viruses recognized in nature, but that merely scratches the surface of what exists. As scientists continually seek to identify more, they often visit the sewers, which are both a destination and a breeding ground for viruses. Many viruses are brought in by human and animal feces and urine, plant material, and the insects and rodents that make the sewers their home, but then they proliferate. The viral count expands when the host viruses infect the bacteria, rotifers, amoeba, and fungi that readily (and rapidly) grow in raw sewage. The longer sewage sits, the more viruses are created. Consider that a single bacterium will split, under proper conditions, every 20 minutes; the exponential growth rate amounts to 69 billion in a matter of 12 hours. With today's water conservation efforts creating less flow and longer retention times — think low-flow toilets and urban sprawl — sewers are virtual petri dishes for new bacteria and viruses. In 2011, scientists from the American Society for Microbiology (ASM) were among those who took to the sewers searching for viruses. Most of what they found was brand new — at least to the science and medical community. "The ratio (43,381/3,027) of novel to known 8 wateronline.com ■ viral sequence reads is approximately 10:1," the ASM study concluded. "Our data demonstrate that known viruses represent a small fraction of the viral universe."1 Unknown viruses have equally unknown effects — and some viruses can lay dormant in humans for months or years before surfacing — so there is plenty of potential for unpleasant consequences in the future. But there are also consequences being realized here and now. The Devil We Know The ASM study identified 234 viruses of the known variety in its sewer search, 17 of which are communicable to humans. Such viruses included human adenovirus, human papillomavirus (HPV), cholera, typhoid, HIV, and H1N1. Other scary findings from researchers conducting sewer dives include methicillin-resistant Staphylococcus aureus (MRSA) bacteria, poxviruses, herpesviruses, and hepatitis A virus (HAV). The journal Occupational and Environmental Medicine released a study specific to HAV stating that "frequent occupational exposure to raw sewage was a significant risk factor for HAV infection." The study noted that, "of 50 employees who reported occupational exposure to raw sewage most of the time, 30 (60 percent) had had HAV infection."2 MRSA has even made its way to the treatment plant. From 2009 to 2010, University of Maryland (UMD) researchers tested four water reclamation facilities, taking numerous samples from each throughout the treatment processes. While half of all the extracted samples contained MRSA, only one of the four facilities tested positive for MRSA at the end of treatment.3 Though that is certainly one too many, it is noteworthy that the plant did not employ tertiary treatment by chlorinating its water regularly. With the rise of water reuse and the potential for direct public exposure to the product, this is a sound lesson for reclamation facilities. Water Online The Magazine