Inhalation exposure to volatile organic compounds in the printing industry

This study reports on the occupational inhalation exposure to VOCs of workers in the Kuwaiti printing industry. Using the evacuated canister methodology, we targeted 72 VOCs in three printeries and compared the concentrations to previous reports and relevant occupational exposure levels (OELs). We found that recent efforts in the printing industry to reduce VOC usage had been successful, as concentrations of key hazardous VOCs were substantially lower than anticipated. On the other hand, nearly all target VOCs were found. Non-production areas were sampled along with the offset printing areas, another strength of this study, and revealed exposures to hazardous VOCs among administers and digital printer and CTP operators. Exposure to ototoxic VOCs amounted to 1–3% of the OEL, consisting mostly of ethylbenzene, which was likely in use in two of the study printeries. Exposure to carcinogenic or probably carcinogenic VOCs was 15–20% of the OEL at four locations across the three printeries, consisting mostly of vinyl chloride and benzyl chloride. Vinyl chloride VOC was partially sourced from outdoors, but was also likely used inside the study printeries. Interestingly, concentrations of vinyl chloride were similar in most sampling locations to that of CFC-114, a CFC banned by the Montreal Protocol and not commonly used as a refrigerant. This unexpected finding suggests further study is warranted to identify the use of these VOCs in printeries. Exposure to hazardous VOCs up to nearly 50% of the OEL, consisting largely of bromoform and vinyl chloride. Bromoform was found in all the study printeries, sourced partially from outdoor air. The higher concentrations found inside the study printeries likely resulted from the use of the desalinated water for washing. This finding raises of emissions from sources other than blanket washes, and inks, etc. adding to the total VOC load in printery indoor air. Implications: Results from this study indicate that efforts to reduce worker exposure to VOCs particularly dangerous to human health in recent years have been successful, but there is still much to be done to protect workers. Exposures to ototoxic and carcinogenic VOCs were identified, among both production and non-production workers. Unexpected findings included the apparent use in printing activities of the carcinogen vinyl chloride and CFC-114, banned under the Montreal Protocol. Observed lapses in safety procedures included failure to utilize ventilation systems and closing doors between work areas, indicating management and worker education should remain a priority.

本研究针对科威特印刷行业工人的职业性吸入VOCs（挥发性有机化合物，Volatile Organic Compounds）暴露情况展开分析。采用抽真空罐采样方法，对3家印刷厂的72种VOCs进行了靶向检测，并将检测浓度与既往研究报告及相关职业接触限值（OELs, Occupational Exposure Limits）进行对比。研究发现，近年来印刷行业降低VOC使用量的举措已取得成效，关键有害VOCs的浓度远低于预期。不过，本次研究仍检出了几乎所有靶向VOCs。本研究的另一项优势在于，除胶印区域外，同时对非生产区域进行了采样，结果显示行政人员、数码印刷员及CTP（计算机直接制版，Computer-to-Plate）操作员均存在有害VOCs暴露风险。耳毒性VOCs的暴露量约占OELs的1%~3%，主要成分为乙苯，该物质大概率在本次研究中的2家印刷厂内被使用。在3家印刷厂的4个采样点，致癌或疑似致癌VOCs的暴露量约占OELs的15%~20%，主要成分为氯乙烯和苄基氯。氯乙烯VOC部分来源于室外空气，但也可能在本次研究的印刷厂内被使用。值得注意的是，多数采样点的氯乙烯浓度与CFC-114（蒙特利尔议定书禁用的氯氟烃（CFC, Chlorofluorocarbon），且目前已不再作为制冷剂普遍使用）的浓度相近。这一意外发现表明，有必要开展进一步研究以明确此类VOCs在印刷厂中的使用情况。有害VOCs的暴露量最高可达OELs的近50%，主要成分为溴仿和氯乙烯。本次所有研究的印刷厂中均检出溴仿，其部分来源为室外空气。印刷厂内检出的更高浓度溴仿，可能源于使用脱盐水进行清洗作业。这一发现提示，除了槽式清洗液、油墨等来源外，还存在其他VOCs排放源，进一步增加了印刷厂室内空气中的VOC总负荷。研究启示：本研究结果显示，近年来为降低工人接触对人体健康危害较大的VOCs所采取的举措已见成效，但在保护工人健康方面仍有大量工作有待推进。生产及非生产岗位的工人均存在耳毒性和致癌性VOCs暴露风险。本次研究的意外发现包括，印刷作业中竟使用了《蒙特利尔议定书》禁用的致癌物氯乙烯及CFC-114。研究观察到的安全规程疏漏包括未启用通风系统、未关闭工作区间的房门，这表明加强管理层与工人的安全教育仍应作为工作重点。