Air Monitoring at Moss Landing, CA August 13 23, 2007

Transcription

1 Air Monitoring at Moss Landing, CA August 13 23, 2007 Pesticide Research Institute Report Update, April 7, 2010 Table of Contents Table of Contents... 1 Abstract... 2 Introduction... 4 Site Description, Application Details, and Sampling Overview... 4 Study Setting and Sample Sites... 4 Fumigant Application Information... 4 Sampling Overview... 4 Weather Monitoring... 7 Sampling Periods... 7 Sampling and Analysis of Methyl Bromide and 1,3-Dichloropropene... 7 Sampling of Methyl Bromide and 1,3-Dichloropropene... 7 Analysis of Methyl Bromide and 1,3-Dichloropropene... 8 Sampling and Analysis of Chloropicrin... 8 Sampling of Chloropicrin... 8 Analysis of Chloropicrin... 9 Site Photos Results Methyl Bromide ,3-Dichloropropene Chloropicrin Discussion Reference Exposure Levels Methyl Bromide Toxicology and Reference Exposure Levels Comparison of Study Data to Reference Exposure Levels ,3-Dichloropropene Toxicology and Reference Exposure Levels Comparison of Study Data to Reference Exposure Levels Chloropicrin Toxicology and Reference Exposure Levels Comparison of Study Data to Reference Exposure Levels Effects of Wind and Weather Quality Assurance/Quality Control Procedures References Appendix 1: Weather Data for Moss Landing... A-1 Appendix 2: Wind Rose Plots and Wind Histograms for Moss Landing, CA... A-14 Appendix 3: Sample Logs, Chain of Custody, and Laboratory Results... A-33

2 Abstract At the request of California Rural Legal Assistance, Pesticide Research Institute (PRI) conducted air monitoring for the fumigant pesticides methyl bromide, cis- and trans-1,3-dichloropropene (1,3-D or Telone), and chloropicrin on Potrero Road and Laguna Place in Moss Landing, CA on August and August Twelve-hour samples were collected from approximately 6 PM to 6 AM and 6 AM to 6 PM each day over the two sampling periods in order to capture concentration differences between daylight hours, when winds and temperatures are typically at their highest, and nighttime, when lower wind speeds, cooler temperatures and inversion conditions predominate in the Moss Landing area. Prevailing winds were primarily blowing fumigants away from the homes in the first week of sampling and towards the homes in the second week (see Appendices 1 and 2 for detailed weather data). Twenty-one canister samples were taken at the two sites and analyzed for methyl bromide (MeBr) and 1,3-dichloropropene (1,3-D). Nine samples (43%) contained MeBr above the reporting limit. Concentrations ranged from a low of less than the laboratory reporting limit to a high of 12 µg/m 3 (3.1 ppbv) at 8505 Laguna Place, 600 feet from the nearest edge of the southern part of Block 6 on August 14 during the day of the MeBr application. MeBr concentrations were lower at Potrero Road, due to increased distance (1,200 feet) from the fumigated area, with a maximum measured concentration of 5.5 µg/m 3 on August 14 during the day the methyl bromide application occurred. No samples contained methyl bromide above Reference Exposure Levels (RELs) developed by the U.S. EPA, California Department of Pesticide Regulation (DPR) or the California Office of Environmental Health Hazard Assessment (OEHHA). See Tables 3 and 4 for detailed results by sampling period. Six samples (29%) contained 1,3-D above the reporting limit. Total 1,3-D concentrations ranged from a low of less than the laboratory reporting limit to a high of 138 µg/m 3 (30 ppbv). The highest 12-hour concentration of 1,3-D was measured indoors at Potrero Road overnight on August 22-23, 140 feet from the nearest edge of the fumigated field, Block 4. No windows were open inside the home, and the door was only opened twice, once to place the canister in the house and again to pick it up at the end of the sampling period. The measured concentration outside the house for the same time period was nearly identical at 136 µg/m 3. This observation demonstrates that, at least for poorly insulated homes, being inside offers no protection from drifting fumigants. The maximum average 24-hour concentration was 107 µg/m 3, 67% of DPR s acute 24-hour child REL. The 12-day average concentration over the sampling period was 9.3 µg/m 3, which is 1.2% of EPA s short-term REL. Assuming no other 1,3-D exposure during a 6-week time period, a minimum average 6-week concentration was calculated to be 2.7 µg/m 3, 9% of the EPA subchronic REL. An estimate of cancer risk at Potrero Road from 1,3-D exposure was obtained by comparing OEHHA s No Significant Risk Level (NSRL) for 1,3-D of 20 µg/day to estimated exposure. The annual estimated exposure to 1,3-D for someone present at the sampling site continuously during the sampling period was estimated to be 4,039 µg, using an adult breathing rate of 18 m 3 /day. Assuming no other 1,3-D exposure during the year, daily estimated exposure is 11 µg/day or 55% of the NSRL. However, because of the proximity of multiple strawberry fields, additional exposure to 1,3-D is likely. The measured 1,3-D concentrations were somewhat lower at 8505 Laguna Place, due to the slightly greater distance (185 feet) from the fumigated area and different location relative to prevailing winds. The highest 12-hour concentration was 50 µg/m 3 overnight on August 22, and the 24-hour average concentration was 32 µg/m 3, 20% of DPR s acute 24-hour child REL. Twenty-three sorbent tube samples were taken at the two sites and analyzed for chloropicrin, with all samples containing chloropicrin above laboratory reporting limits. Concentrations of chloropicrin were highest during the second week when winds were primarily out of the south and transporting fumigants directly to the houses, and ranged from a low of 0.11 µg/m 3 (0.02 ppbv) to a high of 44.3 µg/m 3 (6.6 ppbv). See Tables 3 and 5 for detailed results by sampling period. The highest concentration of chloropicrin of 44 µg/m 3 was measured at Potrero Road 140 feet from the nearest edge of the fumigated area overnight on August 22, the day Block 4 was fumigated. The measured concentration is 152% of OEHHA s acute 1-hour REL. [NOTE: A 1-hour acute REL may not be adequately health protective for a 12-hour exposure.] The highest 24-hour average concentration was 42 µg/m 3 on August The 12-day average concentration over the entire sampling period was 4.5 µg/m 3, which is 250% of EPA s short-term REL. Assuming no other chloropicrin exposure during a 6-2

3 3 week time period, a minimum average 6-week chloropicrin concentration was calculated to be 1.3 µg/m 3, 72% of EPA s proposed subchronic REL. Chloropicrin concentrations were somewhat lower at 8505 Laguna Place, due to the slightly greater distance (185 feet) from the fumigated area and different location relative to prevailing winds. The highest 12-hour concentration was 40 µg/m 3 overnight on August 22, 138% of OEHHA s 1-hour acute REL. The 24-hour average concentration was 40 µg/m 3, 138% of OEHHA s acute 1-hour child REL. The 12-day average concentration over the sampling period was 4.3 µg/m 3, which is 238% of EPA s shortterm REL. Assuming no other 1,3-D exposure during a 6-week time period, a minimum average 6-week concentration was calculated to be 1.2 µg/m 3, 67% of EPA s proposed subchronic REL. Comparison of these measured concentrations to DPR s acute and subchronic non-cancer RELs from the 2010 Risk Characterization Document indicated that the highest 12-hour concentration was 1.5 times the one-hour Reference Exposure Level (REL, the concentration below which no adverse effects are anticipated) for both adults and children. The highest 24-hour concentration was 6.8 times the 24-hour REL for a one-year-old child. Cancer risks are of concern as well. Assuming the community was only exposed to chloropicrin during an 8-day time period each year (the number of days for which data are available from this study), a child living on Potrero Avenue from age 2 through age 16 would have a cancer risk at least 232 times the one in one million risk California EPA deems acceptable. A two-yearold who had lived there since birth would have a cancer risk at least 81 times the acceptable value. The fact that additional fumigations occurred over the subsequent six weeks and that very high concentrations were observed on the last sampling day indicates that the cancer risk calculated for the eight days of sampling is a minimum risk estimate. The 6-week average concentrations are also minimum estimates; actual values are very likely to be higher because concentrations of chloropicrin were still high at the end of the sampling period, suggesting that exposure was likely to continue after that point in time if the winds continued to blow from the south, southeast, or southwest. Also, additional chloropicrin applications were conducted on the remainder of the Rodoni property over the month following the sampling period.

4 Introduction At the request of California Rural Legal Assistance, Pesticide Research Institute (PRI) conducted air monitoring for the fumigant pesticides methyl bromide, cis- and trans-1,3-dichloropropene (1,3-D or Telone), and chloropicrin on Potrero Road and Laguna Place in Moss Landing, CA. The goals of the monitoring were to determine: 1) If the above-mentioned fumigant pesticides were transported away from the Springfield Farms/Rodoni application site onto adjacent properties on Potrero Road and Laguna Place during and after fumigant pesticide applications, and if so; 2) At what concentrations these pesticides were found in the air in the yards and homes of the community residents. This report summarizes the results, as well as the sampling and analysis procedures used in this monitoring study. Site Description, Application Details, and Sampling Overview Study Setting and Sample Sites Moss Landing Heights is a community of approximately 50 homes just north of the Rodoni property and adjacent to the Old Salinas River channel and the Salinas River State Beach to the west and the Monterey Bay Aquarium Research Institute to the northwest. Two homes in Moss Landing Heights were selected as sampling sites, Potrero Road (Waypoints: N ; W ) and 8505 Laguna Place (Waypoints: N ; W ), marked with red stars in Figures 1 and 2. Samplers were placed where they could be secured and where people were likely to spend time. Fumigant Application Information Fumigant applications were by tarped, shallow (25-30 cm), broadcast shank injection. 1 Plastic tarps were applied immediately and taped along the seams, and tarp edges were covered with soil. The perimeter of the tarp was sprinkled with water approximately twice per day after applications. Table 1 summarizes fumigant application information. Table 1: Fumigant Application Information 4 Application Date and Time Location Area Treated (acres) Fumigant Applied Application Rate (lbs/acre) 8/14/07, 6:45 10:25 AM Block 6, South 8 Tri-Con 50/50 MeBr: 190 Chloropicrin: 190 8/15/07, 6:35 8:35 AM Block 6, North 4 Telone II Tri-Clor 1,3-D: 151 Chloropicrin: 190 8/22/07, 6:15 8:35 AM Block 4 9 Telone II Tri-Clor 1,3-D: 151 Chloropicrin: 190 Source: Reference 1 and Appendix 1. *Prevailing wind direction is defined here as the direction the wind is coming from. Prevailing Wind Direction* and Average Wind Speed during Application East, West-Southwest 2.3 mph East, East-Northeast 0.8 mph South 1.7 mph Sampling Overview Air monitoring was conducted during two time periods coinciding with fumigant applications to the Rodoni property. 1) August 13-17, 2007: Block 6, fumigated with two separate applications. a. August 13: Eight acres in the southern part of Block 6 were fumigated with Tri-Con 50/50, a 50:50 mix of methyl bromide and chloropicrin. The sampling sites at 8505 Laguna Place and Potrero Road were approximately 600 feet and 1,200 feet from the nearest edge of the fumigated area, respectively. 2

5 5 b. August 15: Four acres in the northern part of Block 6 were fumigated with a 50:50 mix of Telone II (1,3-dichloropropene) and Tri-Clor (chloropicrin). The sampling sites at 8505 Laguna Place and Potrero Road were approximately 250 feet and 1,020 feet from the nearest edge of the fumigated area, respectively. 2 2) August 21-23, 2007: Block 4, nine acres were fumigated with a 50:50 mix of Telone II (1,3- dichloropropene) and Tri-Clor (chloropicrin). The sampling sites at 8505 Laguna Place and Potrero Road were 185 feet and 140 feet from the nearest edge of the fumigated area, respectively. Figure 1: Aerial view of the Moss Landing Heights community, with Rodoni farm fields visible south of Potrero Road.

6 Figure 2: Map of Springfield Farms and Moss Landing Heights. Distances are not to scale. 6

7 7 Weather Monitoring Prevailing winds were variable in the area, but a typical pattern in August is winds averaging 5 7 mph during daylight hours with stronger winds from the west in the afternoon, decreasing to 1 2 mph average wind speed at night, with periods of overnight calm associated with arrival of a foggy marine inversion layer that typically clears by mid-morning. A Davis VantagePro weather station was installed at Potrero Road, with the wind vane aligned with true north (15 degrees east correction from magnetic north) and raised to a height of 5.1 m to clear obstructions. Average temperature, humidity, wind speed and direction were recorded every 15 minutes over the two sampling periods. See Appendices 1 and 2 for detailed weather data for the sampling periods. Sampling Periods Twelve-hour samples were collected from approximately 6 PM to 6 AM and 6 AM to 6 PM each day over the two sampling periods in order to capture concentration differences between daylight hours, when winds and temperatures are typically at their highest, and nighttime, when lower wind speeds, cooler temperatures and inversion conditions predominate in the Moss Landing area. 3 Sampling and Analysis of Methyl Bromide and 1,3-Dichloropropene The fumigants methyl bromide and cis- and trans-1,3-dichloropropene (Telone) were collected and analyzed using US EPA method TO-15, 4 modified by Air Toxics Laboratory to include cis- and trans-1,3- dichloropropene in the analysis. Sampling of Methyl Bromide and 1,3-Dichloropropene Air samples were collected using passive air sampling into evacuated six-liter Silcosteel SUMMA canisters prepared by Air Toxics Laboratory, ATL (Folsom, CA), and equipped with a critical orifice flow controller. Initial canister vacuum was approximately -30 inches Hg and final vacuum was approximately -5 inches Hg. The connection between the canister and the flow controller was checked for leaks for each canister just prior to sampling. Canisters operated at an integrated flow rate of 7.6 ml/min. Most canisters were placed outside at the sampling sites, with intake port ~0.6 m above the ground, and locked to a tree or fencepost. One canister was placed inside the home at Potrero Road overnight on August 22. The house was vacant and all windows were closed. The front door was opened only at the beginning and end of the sampling period to start and stop the sampling. The house was older, with little insulation. A 12-hour background sample was taken prior to the start of both sampling periods, with the first background sample (August 12) taken overnight prior to the start of any fumigation activities on the Rodoni property and a second background sample taken overnight on August 21 prior to the fumigation of Block 4. A trip spike containing 194 µg/m 3 of methyl bromide and 225 µg/m 3 each of cis- and trans- 1,3-dichloropropene was prepared by ATL and was held with the samples over the first sampling period to verify sample stability. After sampling, canisters were stored at ambient room temperature until ready for shipping to ATL for analysis. Canisters were tracked via canister ID numbers and sample ID numbers, and were shipped with a chain of custody form in three batches to ATL (see Table 2 below). Samples were stored at ambient laboratory temperature prior to analysis. There were no handling errors or analytical procedural errors reported by the lab for any of the samples, and no canister exceeded the recommended maximum holding time of 30 days from the date of preparation. Sample log sheets and chain of custody forms are included in Appendix 3. Exact sampling intervals and approximate start and stop vacuum readings from the canister gauge were noted on canister log sheets (Appendix 2), and summary results are reported in the data tables that follow in the Results section of this report. Canister vacuum readings were measured by ATL before and after transport to and from the field, and these readings were used to calculate the total sample volume

8 8 collected. The 7.6 ml/min integrated flow rate yields a sample volume of 5.47 liters for a 12-hour sampling period. Table 2: Canister Preparation and Shipping Dates Batch Date Prepared by ATL Date Shipped to ATL Date Analyzed 1 8/3/07 8/16/07 8/24/07 2 8/3/07 8/20/07 8/27/07 3 8/20/07 8/24/07 8/31/07 Trip spike 8/10/07 8/20/07 8/27/07 Analysis of Methyl Bromide and 1,3-Dichloropropene On receipt of canisters at ATL, canister pressure was measured and a surrogate spike containing 1,2- dichloroethane-d 4, toluene-d 8, and 4-bromofluorobenzene was added. Canisters were pressurized to 5 psi prior to analysis using GC/MS in the full scan mode. The method involves concentrating up to 0.2 liters of canister gas. The concentrated aliquot is then flash vaporized and swept through a water management system to remove water vapor. Following dehumidification, the sample passes directly into the GC/MS for analysis. 4 Recovery of surrogates was within % of spiked concentrations, within the laboratory s acceptable range of %. Concentrations of MeBr and cis- and trans-1,3- dichloropropene in laboratory spike samples were within % of spiked concentrations, within the laboratory s acceptable range of %. Continuing Calibration Verification (CCV) standard runs were within % of known values, within the laboratory s acceptable range of %, and laboratory blanks showed no detections of MeBr or cis- and trans-1,3-dichloropropene. See Table 7 for all QA/QC results. ATL s instrument detection limits are 1.9 µg/m 3 for MeBr and 2.25 µg/m 3 for cis- and trans-1,3- dichloropropene. Reporting (quantitation) limits depend on final canister pressure and subsequent dilution prior to analysis, and ranged from µg/m 3 for MeBr and µg/m 3 for cis- and trans-1,3- dichloropropene. Analytical results for MeBr and total 1,3-D (sum of cis- and trans-1,3-dichloropropene) determined by ATL are provided in the Results section below. Sampling and Analysis of Chloropicrin Chloropicrin was sampled using the California Air Resources Board sorbent tube method for chloropicrin, 5 and analyzed by EMA Labs (Woodland, CA) using NIOSH method 5600 for extraction and analysis, modified by EMA Labs to use hexane as the extraction solvent. 6 Sampling of Chloropicrin Air monitoring for chloropicrin was conducted by pumping measured quantities of ambient air through XAD-4 resin tubes (SKC Inc., # , 8 x 150 mm, 400/200 mg in front/rear beds respectively). Each sample train consisted of sample tubes attached to a dual sampling manifold with separate flow-controller valves for each tube (see photo below), Teflon fittings and tubing, and a 115 volt AC vacuum pump. Sampling devices were placed at a height of ~1.5 m above ground level in areas where people were likely to spend time outside. In order to ensure the security of the sampling devices, the manifold and flow controller parts of the sampling device were enclosed in a locked box, with tube ends protruding to ensure free air flow around tube openings (see site photos on page 10). Manifold and pump connections were leak-checked after setup and prior to each of the sampling events. Sample tubes were pre-labeled with adhesive labels affixed directly to the sample tube with a project and sample ID, and duplicate samples were kept together in a Ziploc bag with the sample log sheet. Tubes were prepared for use by breaking off the

9 9 sealed glass ends and immediately inserting the tube into the Teflon fitting, with the tube oriented with the front resin bed on the bottom. Bios Defender primary standard flow meters (medium and low range) were used to measure air flow through sorbent tubes at the beginning and end of the sampling periods. Flow rates used in the first week s sampling (August 13-17) were approximately one liter per minute, which resulted in some breakthrough of chloropicrin to the rear bed of the sample tube and possible sample loss in 11 of 14 samples. Analysis of a mid-level (500 ng) field spike through which air was pulled for approximately 12 hours during the first background sampling period indicated that 64% of the chloropicrin spiked onto the tube was recovered from both front and rear beds, compared to an average recovery from laboratory spikes of 107%. Thus, chloropicrin concentrations from the August sampling period are minimum values, and actual chloropicrin concentrations were likely somewhat higher than those reported for samples in which breakthrough was observed. During the second week of sampling (August 21-23), a flow rate of approximately 0.1 liter per minute was used. No breakthrough was observed, even in samples with very high concentrations of chloropicrin, consistent with the field spike sample results from a prior ARB experiment, 7 indicating that this flow rate results in an average 95% recovery (N=4, σ=7%), well within acceptable limits for recoveries. Start and stop times and flow rates were recorded onto log sheets for each sample, and summary data are reported in the data tables that follow in the Results section of this report. Caution was used during field monitoring, transportation, storage, and lab analysis to minimize exposure of samples to sunlight in order to prevent photo-degradation of chloropicrin adsorbed to sample tubes. Subsequent to sampling, the tubes were capped, placed in a Ziploc bag, and stored in a dry ice cooler until they could be shipped to EMA Labs by overnight mail in an insulated container with dry-ice-temperature cold packs. There were no handling errors or analytical procedural errors reported by the lab for any of the samples, and all samples were analyzed within 17 days of the date of sampling. Sample log sheets and chain of custody forms are included in Appendix 3. A field blank sample was taken during the first 12-hour background sampling period and was found to contain low levels of chloropicrin, equivalent to a concentration of 0.11 µg/m 3. A trip blank sample was prepared at the end of the first sampling period to check for potential sample contamination during transport and handling. No pesticides were detected in the trip blank. A trip spike sample was prepared at a level of 500 ng, with recovery of 112%. See Table 7 for all QA/QC results. Analysis of Chloropicrin Front and rear beds of sorbent tubes were extracted separately, using 3.0 ml of hexane for each bed. Analysis was by GC-ECD, with ID confirmed by a dual column analysis on each injection. EMA Labs reporting limit for chloropicrin was 0.03 µg per tube, which translates to an air concentration of µg/m 3 for a 12-hour sample at a flow rate of 1.0 L/min, and 0.42 µg/m 3 for a 12-hour sample at a flow rate of 0.1 L/min. Laboratory spike sample recoveries ranged from %, with an average (N=4) of 107%. Laboratory blank samples (N=2) and the trip blank sample contained no detectable chloropicrin. See Table 7 for all QA/QC results. Analytical results for chloropicrin are provided in the Results section below.

10 10 Site Photos 8505 Laguna Place, with sorbent tube sampler on Manifold and flow Canister location at 8505 Laguna Place garage. valves in locked box. L to R: Weather station (on tripod); canister locked Wind vane placement at to tree; sorbent tube samplers on fence at Potrero Road. Potrero Road. View to south from front yard of Potrero Road before fumigation. View to south from front yard of Potrero Road after fumigation.

11 Results All field and laboratory results are reported as concentrations of pesticide components in air in micrograms of pesticide per cubic meter of air (µg/m 3 ) and in parts per billion by volume (ppbv). Sample results were not adjusted or corrected for recoveries of quality assurance spike samples. Data are summarized in Table 3 and Figures 3 and 4, with detailed results provided for methyl bromide and 1,3-D in Table 4 and for chloropicrin in Table Concentration (µg/m 3 ) Fumigant Concentrations at Potrero Road 8/13/07 8/23/07 Moss Landing, CA Methyl bromide 1,3-D (Telone) Chloropicrin * = not detected # = not sampled Fumigation Days Inside Outside 0 * * * * * * * * * # # * # # * * # * # # * * 8/13/07, 6 PM 8/14/07, 6 AM 8/14/07, 6 PM 8/15/07, 6 AM 8/15/07, 6 PM 8/16/07, 6 AM 8/16/07, 6 PM 8/17/07, 6 AM 8/21/07, 6 PM 8/22/07, 6 AM 8/22/07, 6 PM 8/22/07, 6 PM 8/22/07, 6 AM Start Date & Approximate Time Figure 3: Fumigant concentrations at Potrero Road during the sampling period. See Tables 3 5 for detailed sample data. Concentration (µg/m 3 ) Fumigant Concentrations at 8505 Laguna Place 8/14/07 8/23/07 Moss Landing, CA Methyl bromide 1,3-D (Telone) Chloropicrin * = not detected Fumigation Days 0 * * * * * * * * * 8/14/07, 6 AM 8/14/07, 6 PM 8/15/07, 6 AM 8/15/07, 6 PM 8/16/07, 6 AM 8/16/07, 6 PM 8/17/07, 6 AM 8/22/07, 6 AM 8/22/07, 6 PM 8/23/07, 6 AM * * * Start Date & Approximate Time Figure 4: Fumigant concentrations at 8505 Laguna Place during the sampling period. See Tables 3 5 for detailed sample data.

12 12 Table 3: Summary Sampling Results and Observations Sampling Period Date and Approximate Time MeBr Conc. (µg/m 3 ) Total 1,3-D a Conc. (µg/m 3 ) Chloropicrin Conc. (µg/m 3 ) Primary Wind Direction(s) b Average Relative Percent Humidity Average Wind Speed and Percent Calm Periods Comments/Observations Potrero Road, Moss Landing, CA (1,200, 1,020, and 140 feet from nearest fumigated areas) c 1-0, N 8/13 8/14, 6 PM 6 AM < RL < RL 0.11 SE, S, E 89 2 mph; 11% First background sampling period. 1-1, D 8/14, 6 AM 6 PM 3.0 < RL 2.09 d W, SW, E 82 6 mph; 0% Fumigation start at 6:30 AM, southern part of Block , N 8/14 8/15, 6 PM 6 AM < RL < RL 0.22 S, SE 90 2 mph; 20% 1-3, D 8/15, 6 AM 6 PM 5.5 < RL 2.80 d SW 79 5 mph; 0% 1-4, N 8/15 8/16, 6 PM 6 AM 3.3 < RL 1.01 E, SE, NE 89 1 mph; 24% 1-5, D 8/16, 6 AM 6 PM 4.4 < RL 0.91 d W 74 5 mph; 0% Fumigation start at 5:30 AM, northern part of Block , N 8/16 8/17, 6 PM 6 AM NA NA 0.34 NE, NNE, ENE 83 1 mph; 10% No canister sample taken at this location. 1-7, D 8/17, 6 AM 6 PM NA NA 0.90 d W, SW, WNW 72 4 mph; 2% No canister sample taken at this location. 2-0, N 8/21 8/22, 6 PM 6 AM < RL < RL NA S 92 3 mph; 0% Second background sampling period. Pump failed on chloropicrin sample. 2-1, D 8/22, 6 AM 6 PM < RL SW, S, W 84 5 mph; 0% Fumigation start at 6:00 am for Block 4. Tarps cut on Block , N 8/22 8/23, 6 PM 6 AM < RL S 91 5 mph; 0% 2-2I, N e 8/22 8/23, 6 PM 6 AM < RL 138 NA S 91 5 mph; 0% Indoor canister sample for MeBr & 1,3-D. e 2-3, D 8/23, 6 AM 6 PM < RL S, WNW, W 84 5 mph; 0% 8505 Laguna Place, Moss Landing, CA (600, 250, and 185 feet from nearest fumigated areas) f 1-1, D 8/14, 6 AM 6 PM 12.0 < RL 4.95 d W, SW, E 84 6 mph; 0% Fumigation start at 6:30 AM, southern part of Block , N 8/14 8/15, 6 PM 6 AM 12.0 < RL 3.67 d,f S, SE 90 2 mph; 20% 1-3, D 8/15, 6 AM 6 PM 8.3 < RL 4.94 d,f SW 79 5 mph; 0% 1-4, N 8/15 8/16, 6 PM 6 AM 5.3 < RL 1.63 E, SE, NE 89 1 mph; 24% 1-5, D 8/16, 6 AM 6 PM 7.3 < RL 2.65 d W 74 5 mph; 0% Fumigation start at 5:30 AM, northern part of Block , N 8/16 8/17, 6 PM 6 AM < RL < RL 0.30 d NE, NNE, ENE 83 1 mph; 10% 1-7, D 8/17, 6 AM 6 PM < RL < RL 2.22 d W, SW, WNW 72 4 mph; 2% 2-1, D 8/22, 6 AM 6 PM < RL SW, S, W 84 5 mph; 0% Fumigation start at 6:00 AM for Block 4. Tarps cut on Block , N 8/22 8/23, 6 PM 6 AM < RL 50 g 39.1 f S 91 5 mph; 0% 2-3, D 8/23, 6 AM 6 PM < RL S, WNW, W 84 5 mph; 0%

13 13 Notes for Table 3 N = night; D = day. Calm wind periods defined as wind speed at 0 mph. NA = data not available. See Comments/Observations column for explanation. RL = Reporting Limit, the lowest limit quantifiable by the laboratory. Range of reporting limits: MeBr, µg/m 3 ; 1,3-D, µg/m 3 ; Chloropicrin, 0.03 µg/tube. See Tables 5 & 6. a. Telone II is a mixture of cis- and trans- isomers of 1,3-dichloropropene. Isomers were quantified separately and are reported in the table as the sum of the two isomers. b. Direction(s) in bold are the primary direction(s) for the given sampling period. See Appendix 2 for detailed weather data. c. See discussion of sampling periods on page 1 and the maps in Figures 1 and 2 for an explanation of distances of sampling sites to fumigated areas. d. Minimum concentration. Some breakthrough into rear sample bed observed. e. Sample taken inside the house, with all windows closed and the door opened only to place the canister at the beginning of the sampling period and to pick it up at the end. f. Minimum concentration. Start and stop flow rate differed by >±25%, so the higher flow rate was used to calculate concentration and provide a lower limit on the concentration. g. Average of duplicate laboratory analyses, 49 and 50 µg/m 3.

14 14 Table 4: Methyl Bromide and 1,3-Dichloropropene Canister Sampling Results Sampling Period Canister ID Start Date & Time Stop Date & Time Total Time (min) Total Volume (L) MeBr Conc a (µg/m 3 ) MeBr Conc b (ppbv) Total 1,3-D a,c (µg/m 3 ) Total 1,3-D b,c (ppbv) Potrero Road, Moss Landing, CA 1-0 Bear-A 8/13/2007 5:43 PM 8/14/2007 5:38 AM < 3.1 <0.80 < 3.6 < Early-A 8/14/2007 6:06 AM 8/14/2007 6:19 PM < 3.1 < Loop-A 8/14/2007 6:30 PM 8/15/2007 6:30 AM < 3.1 <0.80 < 3.6 < Star-A 8/15/2007 6:46 AM 8/15/2007 6:28 PM < 3.8 < Square-A 8/15/2007 6:42 PM 8/16/2007 6:44 AM < Fish-A 8/16/2007 7:00 AM 8/16/2007 6:30 PM < 3.8 < Pony-A 8/21/2007 5:39 PM 8/22/2007 5:39 AM < 3.1 <0.80 < 3.6 < Blue-A 8/22/2007 5:45 AM 8/22/2007 5:40 PM < 3.2 < Snow-A 8/22/2007 5:55 PM 8/23/2007 5:57 AM < 3.2 < I Omega-A d 8/22/2007 7:20 PM 8/23/2007 7:00 AM < 3.2 < Coat-A 8/23/2007 6:14 AM 8/23/2007 5:50 PM < 3.3 < Laguna Place, Moss Landing, CA 1-1 Fan-A 8/14/2007 6:31 AM 8/14/2007 6:44 PM < 3.6 < Egg-A 8/14/2007 6:53 PM 8/15/2007 7:04 AM < 3.6 < Sock-A 8/15/2007 7:27 AM 8/15/2007 7:15 PM < 3.9 < Grape-A 8/15/2007 7:23 PM 8/16/2007 6:18 AM < 3.7 < Crab-A 8/16/2007 6:27 AM 8/16/2007 5:56 PM < 3.8 < Pole-A 8/16/2007 6:07 PM 8/17/2007 6:50 AM < 3.0 < 0.76 < 3.4 < Late-A 8/17/2007 7:00 AM 8/17/2007 6:22 PM < 3.3 < 0.86 < 3.9 < Girl-A 8/22/2007 6:25 AM 8/22/2007 6:20 PM < 3.1 < A Rabbit-A-1 e 8/22/2007 6:28 PM 8/23/2007 6:15 AM < 3.1 < B Rabbit-A-2 e 8/22/2007 6:28 PM 8/23/2007 6:15 AM < 3.1 < Book-A 8/23/2007 6:27 AM 8/23/2007 6:31 PM < 3.1 < NA = not available. a. Laboratory reporting limits depend on final canister pressure. Range of reporting limits: MeBr, µg/m 3 ; 1,3-D, µg/m 3. b. Conversion between micrograms per cubic meter (µg/m 3 ) and parts per billion by volume (ppbv): For methyl bromide, µg/m 3 = ppbv x 3.88 and for 1,3-D, µg/m 3 = ppbv x See References 7 and 8 for complete equation. c. Telone II is a mixture of cis- and trans- isomers of 1,3-dichloropropene. Isomers were quantified separately and are reported in the table as the sum of the two isomers. d. Omega-A was taken inside the house at Potrero Road, with all windows closed and the door opened only to place the canister at the beginning of the sampling period and to pick it up at the end. e. Rabbit-A-1 and Rabbit-A-2 are duplicate laboratory analyses.

15 15 Table 5: Chloropicrin Sorbent Tube Results Sampling Period Tube ID Start Date & Time Stop Date & Time Total Time (min) Avg. Flow Rate (L/min) Total Volume (m 3 ) Total Chloropicrin (µg/tube) a Air Conc. (µg/m 3 ) Air Conc. (ppbv) b Potrero Road, Moss Landing, CA 1-0 c Wire-A 8/13/07 5:12 PM 8/14/07 5:27 AM Tree-A 8/14/07 5:45 AM 8/14/07 6:01 PM f 0.31 f 1-2 Purple-A 8/14/07 6:06 PM 8/15/07 6:32 AM Roof-A 8/15/07 6:39 AM 8/15/07 6:33 PM f 0.42 f 1-4 Alpha-A 8/15/07 6:39 PM 8/16/07 6:47 AM Shirt-A 8/16/07 6:51 AM 8/16/07 6:32 PM f 0.14 f 1-6 House-A 8/16/07 6:47 PM 8/17/07 7:14 AM Mom-A 8/17/07 7:21 AM 8/17/07 7:08 PM f 0.13 f 2-0 c Red-A 8/21/07 5:15 PM 8/22/07 5:35 AM 740 NA d NA d NA d NA d NA d 2-1 Boy-A 8/22/07 6:00 AM 8/22/07 6:42 PM Finger-A 8/22/07 5:52 PM 8/23/07 6:04 AM Salt-B 8/23/07 6:11 AM 8/23/07 5:48 PM Field spike Cat-A e 8/13/07 5:12 PM 8/14/07 5:27 AM NA NA 8505 Laguna Place, Moss Landing, CA 1-1 Pencil-A 8/14/07 6:36 AM 8/14/07 5:59 PM f 0.74 f 1-2 Lady-A 8/14/07 6:55 PM 8/15/07 7:10 AM f, g 0.55 f, g 1-3 Bird-A 8/15/07 7:14 AM 8/15/07 7:23 PM f, g 0.73 f, g 1-4 Shoe-A 8/15/07 7:32 PM 8/16/07 6:23 AM Sky-A 8/16/07 6:28 AM 8/16/07 5:31 PM f 0.39 f 1-6 Pillow-A 8/16/07 5:44 PM 8/17/07 6:26 AM f 0.04 f 1-7 Banana-A 8/17/07 6:38 AM 8/17/07 6:14 PM f Rain-B 8/21/07 6:10 PM 8/22/07 6:35 AM 745 NA d NA d NA d NA d NA d 2-1 Knife-B 8/22/07 6:42 AM 8/22/07 6:17 PM Joker-B 8/22/07 6:23 PM 8/23/07 6:30 AM g 5.82 g 2-3 Laurel-B 8/23/07 6:34 AM 8/23/07 6:20 PM NA = not available. a. Laboratory reporting limit, 0.03 µg/tube. b. Conversion between micrograms per cubic meter (µg/m 3 ) and parts per billion by volume (ppbv): For chloropicrin, µg/m 3 = ppbv x See Reference 9 for the complete calculation. c. Background sampling period. d. Sample invalid. Pump failed. e. See Quality Control results Table 7 for spike recovery. f. Minimum concentration. Some breakthrough into rear sample bed observed. g. Minimum concentration. Start and stop flow rate differed by >±25%, so higher flow rate was used to calculate concentration and provide a lower limit on the concentration.

16 16 Methyl Bromide Methyl bromide concentrations were reported directly by ATL in µg/m 3 and ppbv and represent approximate 12-hour average concentrations. It is likely that there were periods of higher and lower concentrations during the sampling period. Twenty-one canister samples (excluding Quality Control samples) were taken at the two sites and analyzed for MeBr, with nine samples (43%) containing MeBr above the reporting limit. Concentrations ranged from a low of less than the laboratory reporting limit of µg/m 3 (depending on canister final pressure) to a high of 12 µg/m 3 (3.1 ppbv) 8 at 8505 Laguna Place on August 14 during the day of the MeBr application to the southern part of Block 6, remaining high overnight. Concentrations were lower at Potrero Road, due to increased distance from the fumigated area, with a maximum measured concentration of 5.5 µg/m 3 on August 14 during the day the methyl bromide application occurred. See Tables 3 and 4 for detailed results by sampling period. 1,3-Dichloropropene Concentrations of cis- and trans-1,3-dichloropropene were reported directly by ATL in µg/m 3 and ppbv and represent approximate 12-hour average concentrations. It is likely that there were periods of higher and lower concentrations during the sampling period. Twenty-one canister samples (excluding Quality Control samples) were taken at the two sites and analyzed for cis- and trans-1,3-d. Six samples (29%) contained 1,3-D above the reporting limit. Concentrations ranged from a low of less than the laboratory reporting limit of µg/m 3 for each isomer (depending on canister final pressure) to a high of 138 µg/m 3 (30 ppbv), sum of cis- and trans-1,3-d. 9 Concentrations of 1,3-D were highest at Potrero Road overnight on August 22 (the day of the third fumigant application closest to the sampling sites) at both indoor and outdoor sampling locations, and remained high the following day on August 23. See Tables 3 and 4 for detailed results by sampling period. Chloropicrin Chloropicrin results were reported by EMA Labs in µg per sample and were converted to concentrations in µg/m 3 according to the ARB method, using the equation below. 7 µg /m 3 = µg chloropicrin measured per sample Start flow rate (L/min) + Stop flow rate (L/min) [( ) /2] Time (min) 1000L 1m 3 Concentrations are approximately 12-hour averages. It is likely that there were periods of higher and lower concentrations during the sampling period. Twenty-three sorbent tube samples (excluding Quality Control samples) were taken at the two sites and analyzed for chloropicrin, with all valid samples containing chloropicrin above the laboratory reporting limits. Two background samples were invalid because the pump failed during the sampling period. Concentrations ranged from a low of 0.11 µg/m 3 (0.02 ppbv) to a high of 44.3 µg/m 3 (6.6 ppbv). 10 Concentrations of chloropicrin were highest at Potrero Road overnight on August 22 (the day of the second fumigant application closest to the sampling sites) and remained high the following day on August 23. See Tables 3 and 5 for detailed results by sampling period. For three samples, the stop flow rate was less than the start flow rate by more than ±25%. Instead of averaging the start and stop flow readings for these samples, the starting flow rate (the highest) was used to obtain a minimum concentration for those samples, as shown in the equation below. µg /m 3 µg chloropicrin measured per sample = 1000L Start flow rate (L/min) Time (min) 1m 3

17 17 Such flow rate instability has been noted in prior chloropicrin sampling conducted by the California Air Resources Board and has been attributed to moisture in the resin cartridges from rain or fog in the air altering the permeability of the resin. 7 The data from this study support this hypothesis, indicating a substantial difference in the start and stop flow rates for overnight samples compared to those for daytime samples when humidity is typically lower (see Table 3). The average difference between the absolute values of the start and stop flow rates of 20% (N=10, σ=6%) were observed for overnight samples and 7% (N=12, σ=7%) for daytime samples. Discussion In this section, we compare measured concentrations in air from this study to available Reference Exposure Levels (RELs) for the three fumigants set forth by various regulatory agencies, including U.S. EPA, the California Department of Pesticide Regulation (DPR), and the California Office of Environmental Health Hazard Assessment (OEHHA). Reference Exposure Levels A REL is defined as a concentration at which no non-cancer adverse effects are anticipated for exposure over a particular time period for a given population. Different standards are sometimes set for children and adults because children are more highly exposed than adults due to the fact that children s breathing rates in m 3 /kg are substantially higher than those of adults. Permissable Exposure Limits (PELs) have also been set for healthy adult workers, but are not designed to be protective of bystanders, especially vulnerable populations like children, pregnant women and those with chronic diseases; thus, PELs are not appropriate for comparison for non-occupational exposure. RELs can be developed for any time period. 11 Acute RELs are generally developed for exposure periods of <1 24 hours and are most relevant for this air monitoring project. Sub-chronic exposures (1 day to 6 months) may also be of concern for some fumigants. While chronic exposure (several years to a lifetime) may be an issue for people living in this area because of the multitude of nearby strawberry farms that utilize fumigants on an annual basis, this monitoring study was not designed to capture longer-term exposures. A lower-bound lifetime cancer risk can be estimated for carcinogenic fumigants like 1,3-D from a single application, assuming similar fumigation activities in subsequent years. Existing RELs for the fumigants methyl bromide, 1,3-D and chloropicrin are summarized in Table 6. As the reader may note, different agencies often develop substantially different RELs for the same chemical and similar time periods. This is a result of using different toxicity studies as the basis for the REL, interpreting the studies differently, and/or using different uncertainty factors in the risk analysis. In this report, monitoring data are compared to the most health-protective RELs available, noting that acute symptoms of poisoning were observed in this study for inhalation exposures that were far below the mostrecently finalized U.S. EPA RELs for chloropicrin, which calls into question the validity of the proposed REL. 12

18 18 Table 6: Reference Exposure Levels and Observed Concentrations Acute 1-hour (µg/m 3 ) Acute 24-hour (µg/m 3 ) Short-term 1 30 days (µg/m 3 ) Subchronic 1 6 mos (µg/m 3 ) Methyl bromide OEHHA 19, 21 3, (adult) 272 (child) 7.8 (adult) 3.9 (child) DPR (adult) 272 (child) 62 (adult) 35 (child) U.S. EPA , Potrero Road 5.5 a, b 4.4 c 0.7 d 0.2 e 8505 Laguna Place 12 a, b 12 c 1.9 d 0.5 e 1,3-Dichloropropene OEHHA DPR (child) (child) U.S. EPA ,250 f Potrero Road 137 a 107 c 9.3 d 2.7 e 8505 Laguna Place 50 a 32 c 2.8 d 0.8 e Chloropicrin OEHHA DPR (adult) 30 (child) 12.8 (adult) 6.2 (child) (adult) 2.4 (child) U.S. EPA g Potrero Road 44 a, b 42 c 4.5 d 1.3 e 8505 Laguna Place 40 a, b 40 c 4.3 d 1.2 e a. Maximum 12-hour average concentration. b. A 1-hour acute REL may not be adequately health protective for a 12-hour time period of exposure. c. Maximum 24-hour average concentration. d. Average over the 12-day period encompassing the two sampling events, with concentrations on non-sampling days assumed to be zero. e. Average over a six-week period encompassing the two sampling events, with concentrations on non-sampling days assumed to be zero. f. Based on a study where rats were exposed to 1,3-D for a single 4-hour period. g. Based on a minute exposure in healthy adult human subjects with no chronic respiratory diseases.

19 19 Methyl Bromide Toxicology and Reference Exposure Levels Methyl bromide is ranked by U.S. EPA as Category I (highly acutely toxic) on product labels because of dermal and ocular toxicity. It is listed by the state of California as a Proposition 65 developmental toxicant, 14 classified as a Hazardous Air Pollutant under the Federal Clean Air Act, 15 and listed as a California Toxic Air Contaminant. 16 Neurotoxic effects have been observed in humans exposed to methyl bromide, 17 and EPA notes that neurotoxicity is the most common toxic effect from inhalation of methyl bromide. 18 Neurotoxicity is the most common toxic effect for inhalation exposure, with neurotoxic effects seen throughout the data base in all tested species of animals. Both acute and 90- day inhalation neurotoxicity studies in rats showed evidence of neurotoxic effects characterized by decreased activity, tremors, ataxia and paralysis. Neurotoxic effects were also seen in the chronic/carcinogenicity inhalation study in mice (ataxia, limb paralysis, degenerative changes in the cerebellum), the developmental inhalation study in rabbits (lethargy, right side head tilt, ataxia), and the Developmental Neurotoxicity Study [DNT] (decreased motor activity). In addition, two subchronic studies showed dogs to be the most sensitive species to the neurotoxic effects of methyl bromide. Risk assessment endpoints for the general population were based primarily on neurotoxic effects. (Reference 18, p. 6) Developmental toxicity is the primary driver for acute toxicity and is the toxic effect on which exposure limits have been based. Developmental effects described as increased incidence of agenesis of the gallbladder and fused sternebrae were also seen in the developmental inhalation study in rabbits. In addition, the multi generation reproduction toxicity study in rats revealed that methyl bromide exposure via the inhalation route resulted in decreases in pregnancy rates and body weights (pups and adults). (Reference 18, p. 13) The California Office of Environmental Health Hazard Assessment (OEHHA) has set an acute REL of 3,900 µg/m 3 for a 1-hour exposure to methyl bromide that should be protective against mild adverse effects such as anorexia, nausea, and headache. 19 The California Department of Pesticide Regulation (DPR) has set an acceptable acute exposure level for a 24-hour period of 815 µg/m Using the same developmental toxicological endpoint as DPR, but different methodology for determining interspecies differences, the U.S. EPA has determined a higher acceptable acute exposure level of 1,300 µg/m See Table 4 for a summary of RELs. Concerns about short-term (1 30 days) and subchronic (1 6 months, seasonal) exposure to methyl bromide have prompted regulatory agencies to develop short-term (DPR) and subchronic (DPR, EPA) RELs. 21 The symptoms of short-term exposure observed in animal studies include the following: Subchronic inhalation exposure of laboratory animals to methyl bromide resulted in altered brain catecholamine levels, decreased brain tyrosine hydroxylase activity, neurotoxicity, tissue degeneration (brain, nasal cavity, heart, testes, adrenal glands, thymus, spleen, and kidneys), and death. Based on overt signs of neurotoxicity, the dog, rabbit, and monkey were more sensitive to methyl bromide than other species (rat, mouse, and guinea pig). (Reference 20, p. 3) and

20 20.. decreased activity... absence of proprioceptive placing and the increased incidence of feces-findings (soft, mucoid feces, and/or diarrhea). (Reference 18, p. 16) DPR defines short-term (1-week) RfC of 272 µg/m 3 (child) and subchronic (6 weeks) RfC of 35 µg/m 3 (child), based on a dog study showing decreased responsiveness. 22 OEHHA did not concur with DPR s RELs and recommended that the subchronic RELs be lowered to 3.9 µg/m 3 for children. 23 In its not-yetfinalized revised human health risk assessment for methyl bromide, U.S. EPA defines only a subchronic (1 day to 6 months) Level of Concern (LOC) for adults and children of 128 µg/m U.S. EPA has not finalized the methyl bromide risk assessment or an acceptable level of exposure to methyl bromide at this time. The methyl bromide risk assessment is due to be finalized in See Table 4 for a summary of RELs. Comparison of Study Data to Reference Exposure Levels With the prevailing winds primarily blowing fumigants away from the homes in the first week of sampling (see Appendix 2) and with no methyl bromide applied in the second week, the highest 24-hour concentration of methyl bromide was observed on August 14 at 8505 Laguna Place, 600 feet from the nearest edge of the fumigated field, at 12 µg/m 3, <1% of OEHHA s acute 1-hour REL and 1.5% of EPA s proposed acute 24-hour REL. [NOTE: A 1-hour acute REL may not be adequately health protective for a longer exposure.] The 12-day average concentration over the sampling period was 1.9 µg/m 3, which is <1% of DPR s short-term REL. Assuming no other methyl bromide exposure during a 6-week time period, a minimum average 6-week concentration was calculated to be 0.53 µg/m 3, 14% of the OEHHA subchronic child REL and <1% of the proposed EPA subchronic REL. 24 Methyl bromide concentrations were lower at Potrero Road, due to the greater distance (1,200 feet) from the fumigated area. The highest 24-hour average concentration of 4.4 µg/m 3 measured on August 16 was <1% of OEHHA s acute 1-hour REL and EPA s proposed 24-hour acute REL. The 12-day average concentration over the sampling period was 0.7 µg/m 3, which is <1% of DPR s short-term REL. Assuming no other methyl bromide exposure during a 6-week time period, a minimum average 6-week concentration was calculated to be 0.19 µg/m 3, 4.9% of the OEHHA child subchronic REL and <1% of the proposed EPA subchronic REL. The 6-week average concentrations are minimum estimates; actual values are very likely to be higher because additional MeBr applications were conducted on the remainder of the Rodoni property over the month following the sampling period. 1,3-Dichloropropene Toxicology and Reference Exposure Levels The fumigant 1,3-D is ranked by U.S. EPA as Category I (highly acutely toxic) on product labels, and as a B2 (Probable) carcinogen. 25 The state of California lists 1,3-D as a Proposition 65 carcinogen. 14 It is also classified as a Hazardous Air Pollutant under the Federal Clean Air Act 15 and listed as a California Toxic Air Contaminant. 16 Acute effects observed in humans exposed to 1,3-D include headache, dizziness, mucous membrane irritation, gasping, coughing, respiratory distress, nausea, and vomiting. 26 Animal studies indicate that exposures to high doses of 1,3-D produced tremors, convulsions, salivation, lacrimation, diarrhea, lethargy and death. 25 Based on body weight reductions in rats exposed to 1,3-D, DPR has set an acceptable acute child REL for a 24-hour period of 160 µg/m U.S. EPA has determined a substantially higher acceptable acute exposure level of 11,250 µg/m 3, based on a single 4-hour exposure of rats to 1,3-D that resulted in decreased body weights. The weight reductions were first noted on day 2 of the study (one day after cessation of exposure) and persisted for 7 days. 25 See Table 4 for a summary of RELs.