1 00:00:00,520 --> 00:00:02,160 VO: Hello, everyone. 2 00:00:02,280 --> 00:00:07,960 Welcome to the tutorial on the Probabilistic Aggregate Consumer Exposure Model... 3 00:00:08,080 --> 00:00:10,320 or PACEM for short. 4 00:00:10,440 --> 00:00:12,640 This video will provide an explanation... 5 00:00:12,760 --> 00:00:16,240 of the underlying methodology used in PACEM. 6 00:00:16,360 --> 00:00:19,360 In addition, an illustrative example will be given... 7 00:00:19,480 --> 00:00:22,960 of how to perform a risk assessment with this model. 8 00:00:23,080 --> 00:00:27,760 But first, let's get a quick overview of the applicability of PACEM... 9 00:00:27,880 --> 00:00:30,800 and why to use it in the first place. 10 00:00:30,920 --> 00:00:35,680 Some chemical substances, for example fragrances and preservatives... 11 00:00:35,800 --> 00:00:39,120 are used in many different consumer products. 12 00:00:39,240 --> 00:00:43,320 To estimate the total daily exposure of a person or population... 13 00:00:43,440 --> 00:00:47,280 exposures to the chemical from all products used on that day... 14 00:00:47,400 --> 00:00:49,120 need to be considered. 15 00:00:49,680 --> 00:00:53,360 PACEM has been developed for this purpose. 16 00:00:53,480 --> 00:00:57,160 PACEM is designed to estimate aggregate exposure to chemicals... 17 00:00:57,280 --> 00:00:59,920 in various consumer products... 18 00:01:00,040 --> 00:01:05,280 by considering various factors, including usage patterns in a population... 19 00:01:05,400 --> 00:01:11,040 product types, and chemical concentrations in the products. 20 00:01:11,160 --> 00:01:13,200 It uses a probabilistic approach... 21 00:01:13,320 --> 00:01:19,000 to provide a comprehensive exposure assessment of a population of interest. 22 00:01:19,560 --> 00:01:24,560 To perform such a probabilistic exposure assessment, PACEM uses information... 23 00:01:24,680 --> 00:01:29,040 about product-use frequencies and product-usage amounts... 24 00:01:29,160 --> 00:01:35,720 of hundreds to thousands of individuals. This information is gathered in surveys. 25 00:01:35,840 --> 00:01:41,520 The individuals questioned in the surveys form the basis of the simulated population. 26 00:01:41,640 --> 00:01:45,680 Specifically, the product-use frequencies and product amounts... 27 00:01:45,800 --> 00:01:51,680 reported by the individual are used to simulate product-usage diaries. 28 00:01:51,800 --> 00:01:56,840 These describe which products are used on each day of a 14-day period. 29 00:01:56,960 --> 00:01:59,760 For each product used on a given day... 30 00:01:59,880 --> 00:02:04,640 a product amount is sampled from the usage information as well. 31 00:02:04,760 --> 00:02:09,280 Once the usage diary has been created, substance concentrations are sampled... 32 00:02:09,400 --> 00:02:13,880 for each product and each individual in the usage diary. 33 00:02:14,000 --> 00:02:19,200 These concentrations are based on input provided by the user of PACEM. 34 00:02:19,320 --> 00:02:23,400 To calculate an individual's exposure to a particular substance... 35 00:02:23,520 --> 00:02:24,920 the product amount used... 36 00:02:25,040 --> 00:02:30,560 is multiplied by the substance concentration in that particular product. 37 00:02:30,680 --> 00:02:35,640 Then, all exposures within a given day of the usage diary are summed... 38 00:02:35,760 --> 00:02:41,600 such that an aggregated exposure is estimated for each 24-hour time frame... 39 00:02:41,720 --> 00:02:45,040 for an individual in a two-week period. 40 00:02:45,160 --> 00:02:48,480 PACEM supports two endpoints of exposure: 41 00:02:48,600 --> 00:02:52,200 short-term exposure and long-term exposure. 42 00:02:53,080 --> 00:02:55,360 When selecting short-term exposure... 43 00:02:55,480 --> 00:03:01,440 the day with the highest aggregate exposure is taken from the 14-day diary. 44 00:03:01,560 --> 00:03:03,680 When selecting long-term exposure... 45 00:03:03,800 --> 00:03:08,400 the average aggregate exposure is taken from the 14 days. 46 00:03:08,520 --> 00:03:11,240 This allows users to select an endpoint... 47 00:03:11,360 --> 00:03:15,280 that fits their exposure and risk assessment best. 48 00:03:15,400 --> 00:03:20,440 Now that you have a global idea of the methodological concepts of PACEM... 49 00:03:20,560 --> 00:03:25,520 let's take a look at the steps required to perform an exposure assessment. 50 00:03:25,640 --> 00:03:30,840 In the first panel of PACEM, the user can select the product groups of interest... 51 00:03:30,960 --> 00:03:37,280 being personal care products and/or household cleaning products. 52 00:03:37,400 --> 00:03:41,000 Then, two types of exposure assessments can be selected: 53 00:03:41,120 --> 00:03:44,560 dermal load and systemic exposure. 54 00:03:44,680 --> 00:03:48,520 Finally, the population needs to be selected. 55 00:03:48,640 --> 00:03:54,000 Currently, France, Germany, Spain, the Netherlands and the UK... 56 00:03:54,120 --> 00:03:56,120 are included in PACEM... 57 00:03:56,240 --> 00:03:58,640 which refers to the product usage surveys... 58 00:03:58,760 --> 00:04:01,840 conducted for individuals of those countries. 59 00:04:02,840 --> 00:04:08,040 Then, in the next panel, relevant product groups need to be selected. 60 00:04:08,160 --> 00:04:15,400 Here, we select aftershave spray, after-sun cream, and liquid all-purpose cleaner. 61 00:04:15,520 --> 00:04:17,760 For each selected product group... 62 00:04:17,880 --> 00:04:20,960 substance concentrations need to be provided... 63 00:04:21,080 --> 00:04:25,160 as well as the percentage of products containing the substance. 64 00:04:26,040 --> 00:04:29,880 This user input is needed to link substance concentrations... 65 00:04:30,000 --> 00:04:35,080 to the product usage diaries that are created based on the surveys. 66 00:04:35,200 --> 00:04:39,320 The last step on this panel is to provide exposure fractions... 67 00:04:39,440 --> 00:04:44,040 or retention factors if performing dermal load assessment. 68 00:04:44,160 --> 00:04:46,960 These fractions are needed to account for situations... 69 00:04:47,080 --> 00:04:51,000 where not all the used products lead to actual exposure... 70 00:04:51,120 --> 00:04:53,800 for example due to rinsing off. 71 00:04:53,920 --> 00:04:56,680 Exposure fractions and retention factors... 72 00:04:56,800 --> 00:05:00,280 are represented by a value between 0 and 1... 73 00:05:00,400 --> 00:05:03,040 with 0 representing no exposure... 74 00:05:03,160 --> 00:05:09,160 and 1 representing exposure to all of the substance used during an event. 75 00:05:09,280 --> 00:05:14,280 The fractions implicitly comprise information on the exposure duration... 76 00:05:14,400 --> 00:05:16,880 the release of the substance from the product... 77 00:05:17,000 --> 00:05:22,720 contact between user and product and the relevant exposure routes. 78 00:05:22,840 --> 00:05:28,440 User input can be provided as point values, but also as distributions. 79 00:05:28,560 --> 00:05:32,960 This can be done by clicking on the button with the distribution symbol. 80 00:05:33,920 --> 00:05:35,040 This will open a panel... 81 00:05:35,160 --> 00:05:38,880 where users can select the type of distribution they want to use... 82 00:05:39,000 --> 00:05:43,560 and provide the necessary input to define that distribution. 83 00:05:43,680 --> 00:05:49,560 By clicking on 'Apply', the selected distribution will be used by PACEM. 84 00:05:49,680 --> 00:05:52,880 Once the product exposure settings have been provided... 85 00:05:53,000 --> 00:05:57,280 one can specify the absorption fractions for each exposure route. 86 00:05:57,400 --> 00:06:03,240 For this example, we assume 50% inhalation and dermal absorption. 87 00:06:03,360 --> 00:06:07,440 In the next panel of PACEM, the Simulation Settings panel... 88 00:06:07,560 --> 00:06:11,520 users can choose the product sample size. 89 00:06:11,640 --> 00:06:13,600 This number reflects the number of times... 90 00:06:13,720 --> 00:06:18,160 an individual is sampled from the information in the survey. 91 00:06:18,280 --> 00:06:20,960 Higher numbers will give more precise results... 92 00:06:21,080 --> 00:06:24,040 but the simulation will take longer to run. 93 00:06:24,160 --> 00:06:26,480 Upon clicking on the submit button... 94 00:06:26,600 --> 00:06:29,960 the exposure assessment will be sent to the PACEM server... 95 00:06:30,080 --> 00:06:32,400 and the calculations will start. 96 00:06:32,520 --> 00:06:37,080 Information on the status of the computations are provided. 97 00:06:37,200 --> 00:06:41,520 Once the status of the computations turns to 'Success'... 98 00:06:41,640 --> 00:06:46,680 users can click on the Analysis button to analyse the results. 99 00:06:46,800 --> 00:06:52,600 We can now take a look at the results and select the endpoints that we want to see. 100 00:06:52,720 --> 00:06:53,840 In this example... 101 00:06:53,960 --> 00:06:59,040 we will take a look at short-term exposure of all females in the population. 102 00:06:59,160 --> 00:07:03,880 You can also see the option to select exposed individuals only... 103 00:07:04,000 --> 00:07:06,520 or the entire population. 104 00:07:06,640 --> 00:07:09,040 By clicking on 'Create Output'... 105 00:07:09,160 --> 00:07:14,800 we can now see the estimated aggregate exposure for the selected population. 106 00:07:14,920 --> 00:07:20,440 Since we selected systemic exposure in the assessment settings of this example... 107 00:07:20,560 --> 00:07:24,240 an aggregate exposure will be shown for each exposure route... 108 00:07:24,360 --> 00:07:28,000 as well as the total aggregate exposure. 109 00:07:28,120 --> 00:07:32,920 If dermal load was selected, only the dermal load would have been shown. 110 00:07:33,040 --> 00:07:34,600 For each exposure route... 111 00:07:34,720 --> 00:07:39,080 various percentiles of the population exposure are given. 112 00:07:39,200 --> 00:07:44,320 In addition, a visualisation of the cumulative exposure is shown below. 113 00:07:44,440 --> 00:07:48,600 Finally, PACEM offers various options to export the results... 114 00:07:48,720 --> 00:07:53,440 by clicking on this symbol with the three horizontal lines. 115 00:07:53,560 --> 00:07:56,000 To summarise, you now hopefully understand... 116 00:07:56,120 --> 00:07:59,640 how to perform an exposure assessment with PACEM... 117 00:07:59,760 --> 00:08:03,640 and have a global understanding of the underlying principles. 118 00:08:04,560 --> 00:08:10,040 We hope this tutorial has helped you to familiarise yourself with PACEMWeb. 119 00:08:10,160 --> 00:08:12,520 Our support does not end here. 120 00:08:12,640 --> 00:08:18,720 Visit the PACEM website to find help pages that provide information on PACEMWeb... 121 00:08:18,840 --> 00:08:20,760 and a user manual. 122 00:08:20,880 --> 00:08:25,160 You can also access the 'i' and '?' icons within the software... 123 00:08:25,280 --> 00:08:28,560 which are there to give you extra help when needed. 124 00:08:28,680 --> 00:08:31,440 If you still have questions or need assistance... 125 00:08:31,560 --> 00:08:38,680 please contact us at pacemweb@rivm.nl.