Time bomb warning over impact of bioaerosols on workers

Disclosure of the report's existence and its contents came this week from Dr Alison Searl, director of analytical services at the Institute of Occupational Medicine (IOM) in Edinburgh, who warned of a “bioaerosols time bomb”.

She explained that the study was commissioned from the IOM by the Department for Environment, Food and Rural Affairs (Defra), which wanted information about links between bioaerosols and their impact on health.

A spokesman for Defra told letsrecycle.com that “the report is currenty being peer-reviewed and we hope to publish it shortly”.

The IOM describes itself as “a major independent centre of scientific excellence in the fields of occupational and environmental health, hygiene and safety.” It was founded as a charity in 1969 by the UK coal industry in conjunction with the University of Edinburgh and became independent in 1990.

Dr Searl was addressing a conference held by the Association for Organics Recycling (AFOR) in Coventry and chairman Mike Smith, technical advisor to the Environment Agency, reflected that he was concerned about some of the comments made by Dr Searl.

Health issues

The IOM scientist said that the “meat of the Defra project was to link a level of exposure” to health issues. “Defra were also concerned about the effects of bioaerosols on susceptible groups of the population”

The bioaerosols were of five types; organic dusts, bacteria, endotoxins, fungi and beta
glucan from plant cells.

Explaining the potential impact of bioaerosols, Dr Searl said: “Clearly bioaerosols are everywhere and are not very good for you, potentially giving you respiratory system problems, headaches and fatigue. Bioaerosols are going to become a major health issue for waste workers. Hand-sorting of waste gives rise to a very high level of exposure to bioaerosols.”

She went on to say that the problem was like a “timebomb of major respiratory health problems in the future”.

Difficulties in quantifying the impact of bioaerosols were significant, she conceded, because it was difficult to measure health issues such as coughs: “There are marked inconsistencies in exposure responses reported in different studies.”

Organic dusts

Looking at “who is at risk?” Dr Searl said that a substantial minority of individuals were susceptible to developing respiratory systems at background levels of bioaerosols exposure. “There is no safe level of exposure for the most vulnerable populations. Bioaerosols are bad for you and need to be controlled.”

She ended her presentation with a number of recommendations including the consideration of site specific guidelines, accessible guidance on the health effects from different levels of bioaerosols exposure.

Perspective

Following on from Dr Searl, Dr Brian Crook, microbiology team leader at the Health and Safety Laboratory – an agency of the Health and Safety Executive (HSE) – sought to put the bioaerosols issue into perspective.

He described work currently being undertake for the HSE which had seen six composting facilities visited 14 times to obtain bioaerosol measurements at different times of the year and from different parts of the site, including vehicles and workers' lapels. These included in-vessel composting sites with a focus on the incoming material and where organics were handled outside the vessels.

The research worker confirmed the validity of the Environment Agency's 250 metre protection zone around sites and also highlighted the importance of measures to protect workers.

In particular, Dr Crook emphasised the importance of ensuring that tractor and loader cabs were sealed to protect the operative. “Our results demonstrated the protection afforded by not being directly exposed to those bioaerosols.”

He also advocated the creation of risk zones, with composters assessing the measures that need to be taken to protect workers. “If you work next to compost handling machinery and are not projected within a vehicle there is a 64% chance of being exposed to more than 1,000,000 colony forming units per cubic metre of bacteria. If you move into a vehicle cab, this drops considerably to 28%.”

The research work, to be published later in the year, said Dr Crook, adds to current data. “It established composting bioaerosol levels facing workers; it shows the extent of protection offered by cabs; it offers advice on a risk zone approach; and it provides information for modelling down wind dispersion.

The work, he added, helps assess the potential for respiratory ill health and also provides an understanding of health and safety measures that can be adopted on sites.

Kerbside

Speaking after her presentation, Dr Searl told letsrecycle.com that she did have strong concerns about bioaerosols and their impact in the waste sector. She confirmed that there was a risk too from recyclables sorted at the kerbside as happens in Edinburgh. “These waste cans, bottles and newspapers sit there for a fortnight. The industry has an issue – it doesn't have the health data and would really benefit from screening its workers now to protect itself against future legislation.”

Dr Searl added that workers in the waste sector had not been exposed to bioaerosols over a long enough number of years for the full effects of bioaerosols to be assessed.