Figure 2: Nano- particles are deposited deep into the lungs


Governmental Industrial Hygienists (ACGIH) of 0.02 mg/m³ is the one that is most commonly adopted and it serves as a ref- erence in the absence of an OEL value. However, stricter oper- ational exposure limits are currently under review in the EU. Following a request from the European Commission, experts from the European Chemicals Agency (ECHA) issued an opin- ion in March 2020 proposing a limit value of 0.00001 mg/m³, which would be very challenging for the feed industry. Other values are currently being evaluated. A decision is expected in the coming months.


Special case with nanoparticles Among substances likely to have an impact on workers’ safety due to their strong dusting potential, nanomaterials are a growing concern. Despite a particle size a thousand times smaller than commonly used micro-substances, there are cur- rently no specific regulations concerning the handling of na- nomaterials. At first sight, the animal nutrition sector is main- ly concerned with certain sources of silica, but the current regulatory framework does not make it possible to identify all products derived from nanotechnologies. Indeed, substances that may have been authorised as additives in a conventional form have since been marketed in a nano form without the need to notify this. Moreover, the lack of a clear definition and well-defined analytical method capable of evaluating tiny particles does not facilitate their classification as a nano- material. Nanoparticles are deposited deep into the lungs in a much higher proportion than micrometric particles (Figure 2) and several studies indicate the greater toxicity of nanosized particles compared to particles of the same chemical nature in micro form. Nanoparticles of copper, for example, induce grave toxicological effects and serious damage in the kidneys, liver and spleen of experimental mice, whereas micro-copper particles do not (study conducted in 2006). Other studies also suggest the possibility of inflammatory, respiratory, cardio- vascular or neurological effects. Even if nano applications sound promising, there is a lack of data on toxicity and meth- ods of measuring exposure, which would be needed to estab- lish occupational exposure limit values. It is therefore


appropriate to aim for the lowest possible level of exposure, regardless of the operation being carried out.


Nickel in trace minerals soon to be regulated? Contaminants in feed materials can also be a source of risk for workers. For this reason, nickel is currently under discussion at the European level. Indeed, this heavy metal, which is not yet regulated in feed (as are arsenic, cadmium and lead), can have adverse effects on workers handling contaminated ingredi- ents. In a range of 10 -100 mg/m³ an increased cancer risk has been identified, in particular for respiratory system, and other health problems have been recorded, including allergic skin reactions. So far no European directive has defined an OEL for nickel, but in 2011 the Scientific Committee on Occupational Exposure Limits (SCOEL) recommended a limit of 0.005 mg/m³ for respirable dust and 0.03 mg/m³ for inhalable dust. Concen- trations of trace minerals can be very high: more than 200 ppm on average. Consequently, with very dusty minerals, ex- posure of workers to nickel in feed factories could be a con- cern. This explains why maximum limits for nickel in feed ma- terials are under discussion. In February 2020, the Standing Committee on Plants, Animals, Food and Feed (ScoPAFF) pro- posed a limit of 200 ppm for trace elements compounds.


Conclusion Today, more and more regulatory measures are being imple- mented to secure workers’ safety. This applies in particular to the feed industry where potentially hazardous substances, mainly minerals, are daily handled in factories. Because dusty products increase the exposure of workers to chemical agents, the European Commission is focusing more on particle size and dusting potential when authorising new feed additives. Employers are also required to regularly monitor the degree to which their workers are exposed to various chemical substanc- es and to minimise this exposure through preventive meas- ures (personal protective equipment, dust extraction systems, etc.). Careful selection of feed additives is essential and it is im- portant to use products with superior technological properties which are well defined by the supplier.


▶ ALL ABOUT FEED | Volume 28, No. 9, 2020 11


PHOTO: ANIMINE


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