Field EDD Group The Field Group consists of data tables for data obtained during subsurface investigations and other field activities at a site. The Field EDD consists of 10 data tables (Table 3.2): DrillActivity_v1 DownholePoint_v1 Lithology_v1 WellConstruction_v1 WaterTable_v1 WaterLevel_v1 ExtractionInjectionWells_v1 FieldSample_v1 FieldResults_v1 Table 3.2: General Information on the Field EDD Sections Name Description Completed By Submission Frequency Data Requirements DrillActivity_v1 Contains general information pertaining to all drilling activities (well construction, soil borings, or other) that take place at a project site. Data Providers Field Personnel Once per location The sys_loc_code and drill_event fields need to be populated for each drilling activity event. DownholePoint_v1 Contains data consisting of a depth, a parameter, and a reading, which are collected during drilling, direct push sampling, borehole logging, or some other means of downhole data collection. Examples of downhole point data include photoionization Data Providers Field Personnel Once per location or when subsequent logs are run in a well installed at the location All fields in this EDD section are required for submittal (sys_loc_code, depth, param, param_value, param_unit, and measurement date).
Description Procedure (MTDOT Soil Mechanics Bureau STP-2 dated May 1, 1975, as amended). Rock should be described using standard geologic terms for the rock type encountered in the borehole. Well_ v1 Contains basic information for each well and is required if the location EDD contains wells. Important information captured in this EDD include the well owner, measuring point elevation, depth of the well, whether or not the well includes a sump, pump information, stickup height, and installation date. Data Providers Field Personnel Once per location This EDD will include all wells installed at the site and shall be submitted when well installation is complete and when the datum value of the well is changed. For example, if a well is converted from stickup to flush-mount and the inside casing is cut down then the datum value (top of casing elevation in this case) has been changed and the Well EDD would be submitted to document this change. Following is a description of the fields in this section: WellConstruction_v1 Contains well construction information, such as casing length, screened interval, backfill information, and other construction details. Data Providers Field Personnel Once per location or when the surface completion or top of casing elevation or datum value is changed For each well on the Well_v1 EDD section multiple records describing the components of a well, such as the collar, casing, screen and materials used can be placed in the WellConstruction_v1 EDD section at their respective depths for each well. The following fields are required by MTDEQ for documenting well construction details in the WellConstruction_v1 EDD section: sys_loc_code – Sample location id for a well that must be unique within a facility
segment_type – A code from the rt_well_segment_type valid value table describing the individual section of the well, such as “FILTER PACK”. material_type_code – A code from rt_well_segment_type valid value table describing the material used in an individual section of a well, such as “SAND PACK”. start_depth – The depth, in ft. bgs for the top of the well segment. end_depth – The depth, in ft. bgs for the bottom of the well segment. depth_unit – The unit of depth measurement for start and end depth, must be in ft. inner_diameter – A representing the inner diameter of the segment_type. outer_diameter – A value representing the outer diameter of the segment_type. diameter_unit – The unit of measure for the and outer diameter measurements. slot_type – The type of well screen slots in the well screen such as bridge, shutter, and continuous. slot_size – The width of the slots in the well screen. slot_size_unit – The unit of measure for the slot size measurement. perf_length – The length of the well screen. screen_type – The type of well screen used such as pipe based screen, rod based screen, “v” wire, slotted, or perforated plate. WaterLevel_v1 Contains information on groundwater levels measured Data Providers Field Personnel MTDEQ requires the fields listed below be populated: sys_loc_code – Sample location ID for a well that
during sampling activities, synoptic rounds of level measurements, or other groundwater monitoring events. must be unique within a facility. measurement_date – The date and time a water level measurement was collected at a well. historical_reference_elev – The elevation of the reference point from which water level depth measurements were taken. water_level_depth – The depth of water below the reference point. water_level_elev – The elevation of the water level calculated by subtracting the water_level_depth from the historic_reference_elev. measured_depth_of_well – The depth, in ft., of the bottom of the well. depth_unit – The units used for measuring the water_level_depth, water_level_elev, and depth of a well. Technician – The name of person collecting the water level measurements. dry_indicator_yn – “N” if you are able to obtain a water level measurement or “Y” if the well is dry. measurement_method – The method of measuring the water table depth (e.g. water level indicator). WaterTable_v1 Contains information to document the first encounter with the water table and subsequent stabilization during drilling of a boring. Data Providers Field Personnel Once per location MTDEQ requires the fields listed below be populated: sys_loc_code – Sample location ID for a well that must be unique within a facility type – The type of aquifer encountered such as “upper,” “lower,” “unconfined” etc. sequence – Enter either “Stabilized” or “Unstabilized” depending on the water level conditions at the time of measurement.
including types of samples, matrix that the sample was collected from, data and location the sample was collected. value, including spikes and duplicates. sample_matrix_code - Matrix code representing the sample matrix as defined in the field. sample_type_code - The code which distinguishes between different types of samples. For example, normal field samples must be distinguished from laboratory method blank samples, etc. sample_source sample_date - The date and time the sample was collected (in MM/DD/YYYY HH:MM:SS format). composite_yn – “Y” if the sample is a composite sample, "N" if not. FieldResults_v1 Contains field parameters collected during sampling events, such as groundwater quality parameters, including turbidity, temperature, specific conductance, pH, Eh, and dissolved oxygen. Field test kit results for parameters, such as ferrous iron, which are analyzed in the field, may also be entered into this EDD. Data Providers Personnel Whenever investigation data are collected and provided to MTDEQ MTDEQ requires the fields listed below be populated: data_provider – Valid value from rt_company or data provider EDD section for organization collecting the field results. sys_loc_code – The sample location ID where field results were taken. sys_sample_code – The sample that is associated with the field results collected. field_parameter – The CAS number code from rt_analyte representing the field parameter collected. start_depth – The start depth below ground surface or water surface of the sample interval. end_depth – The end below ground surface or water surface of the sample interval. depth_unit – The sample start and end depth unit. result_date – The date the field parameter measurement was taken. result_time – The time the field parameter measurement was taken.
result_value – The numeric value of the field parameter result or reading. Or a text value indicating NR for no reading or ND for result_unit – The unit of measurement pertaining to the field parameter result collected. quantitation_limit or reporting – The concentration level above which results can be measured by the instrument. task_code – a code describing the sampling effort. Please consult with the MTDEQ PM regarding these codes. sample_matrix_code – The matrix valid value code representing the field sample matrix. qualifier – A field parameter qualifier to denote detections and sampling_company_code – Company code for company collecting the sample. sampling_method – The sampling method used when collecting the field parameter reading. reportable_result – Enter “Yes” for usable results considered reportable and “No” for results collected that are not useable and not reportable. results for field parameters may be caused by equipment malfunction or improper field procedures. value_type – Enter how the final field parameter result was derived as either “Actual,” “Calculated,”, or “Estimated.” detect_flag - May be either "Y" for detected analytes or "N" for non-
The Vapor Intrusion EDD Group consists of data tables for inventorying buildings and structures, cataloging factors that impact air quality within structures and for the location, sample and chemistry results for soil vapor, indoor air and ambient outdoor air samples collected. The Vapor Intrusion EDD consists of three data tables (Table 3.3): VI_BuildingInspection_v1 VI_TaskParameters_v1 VI_Samples_v1 Table 3.3: General Information on the Vapor Intrusion Group EDD Sections Table Name Description Completed By Submission Frequency Data Requirements VI_BuildingInspection_v1 Contains data that inventories buildings and structures, cataloging factors that impact air quality within structures. Replaced the legacy occupied building questionnaire. Data Providers Vapor Intrusion Team Once per building inspection MTDEQ requires the fields listed below be populated: building_code– For each building, this building code must be unique and all upper case. building_name– This can be a more descriptive name for the building. inspection_date – The date the building inspection was conducted. task_code – The unique identifier for the task. VI_TaskParameters_v1 Contains data specific to the VI Task, for example start/end weather, start/end atmospheric pressure, etc. Data Providers Vapor Intrusion Team Anytime structure sampling data are collected and provided to MTDEQ MTDEQ requires the fields listed below be populated: task_code – The unique identifier for the task. parameter_code – The task parameter. VI_Samples_v1 Contains sample information collected from Ambient Air, Indoor Air, and Subslab Soil Vapor Sampling forms Data Providers Intrusion Team Anytime structure sampling data are collected and provided to MTDEQ MTDEQ requires the fields listed below be populated: data_provider - The unique identifier of the company or agency submitting the data. sys_sample_code - The unique identifier of the sample. Each sample at a facility must have a unique including spikes and duplicates. You have considerable flexibility in the methods used to derive and assign unique sample identifiers, but uniqueness throughout the database is
A detailed description of the data fields in each of the Intrusion EDD Group Sections can be found in Appendix A. Guidance for conducting vapor intrusion investigations can be found at: . Lab EDD Group The Lab EDD Group consists of data tables for analytical samples collected at a subfacility and associated locations. The Lab EDD consists of three data tables (Table 3.4): Sample_v1 TestResultsQC_v1 Batch_v1 Table 3.4: General Information on the Lab Group EDD Sections Table Name Description Completed By Submission Frequency Data Requirements Sample_v1 Contain sample matrix, collection date and time, sample type, etc. Data Providers with from Field Personnel Whenever analytical data are collected and provided to MTDEQ MTDEQ requires the fields listed below be populated: data_provider - The unique identifier of the company or agency submitting the data. sys_sample_code - The unique identifier of the sample. Each sample at a facility must have a unique value, including spikes and duplicates. You have considerable flexibility in the methods used to derive and assign unique sample identifiers, but uniqueness throughout the database is the only restriction enforced by EQuIS®. sample_matrix_code - The code which distinguishes between different types of sample matrix. For example, soil samples must be distinguished from ground water samples, etc. sample_type_code - The code which distinguishes between different types of samples. For example, normal field samples must be distinguished from laboratory method blank samples, etc. sample_source - This field identifies where the sample
DataProvider_v1 Field Name Data Type Key Required Default Parent Lookup Database Mapping(s) Comment Checks company_code Text(40) PK Y rt_company.company_code The unique identifier of the company or agency responsible for completion and submittal of any part of this EDD. company_type Text(20) Y SUBCONTRACTOR rt_company_type.company_type rt_company.company_type The type of company. company_name Text(255) Y rt_company.company_name The name of the data provider. May be more descriptive than company_code. contact_name Text(50) rt_company.contact_name The name of the data provider contact. license_nbr Text(50) rt_company.license_nbr The license number held by the data provider. address_1 Text(40) rt_company.address_1 The street address of the data provider, line one. address_2 Text(40) rt_company.address_2 The street address of the data provider, line two. city Text(30) rt_company.city The city of the data provider. county Text(50) rt_company.county The county of the data provider. Text(10) MT rt_state.state_code The state of the data provider. country Text(50) USA rt_company.country The country of the data provider. postal_code Text(30) rt_company.postal_code The zip code of the data provider. phone_number Text(30) rt_company.phone_number The phone number of the data provider. alt_phone_number Text(30) rt_company.alt_phone_number The alternate phone number of the data provider. email_address Text(100) rt_company.email_address The email address of the data provider. custom_field_1 Text(255) rt_company.custom_field_1 A custom field. custom_field_2 Text(255) rt_company.custom_field_2 A custom field. custom_field_3 Text(255) rt_company.custom_field_3 A custom field. custom_field_4 Text(255) rt_company.custom_field_4 A custom field. custom_field_5 Text(255) rt_company.custom_field_5 A custom field.
custom_field_4 Text(255) dt_chain_of_custody.custom_field_4 A custom field. custom_field_5 Text(255) dt_chain_of_custody.custom_field_5 A custom field. remark Text(2000) dt_chain_of_custody.remark Any additional information about the COC. SDG_v1 Name Data Type Key Required Default Parent Lookup Database Mapping(s) Comment Checks sdg_name Text(20) PK Y dt_sdg.sdg_name The unique identifier of the sample delivery group (SDG) or work order. sdg_desc Text(255) dt_sdg.sdg_desc The description of the SDG. sdg_date DateTime dt_sdg.sdg_date The date and time the SDG was generated. lab_code Text(40) rt_company.company_code dt_sdg.lab_code The laboratory processing the SDG. lab_contact Text(50) dt_sdg.lab_contact The laboratory contact for the SDG. sdg_status Text(9) NEW (Enumeration: sdg_status) dt_sdg.sdg_status The status of the SDG. data_review_date Text(255) dt_sdg.data_review_date The review date for the data associated with the SDG. data_review_company Text(40) dt_sdg.data_review_company The review company for the data associated with the SDG. Equipment_v1 Name Data Type Key Required Default Parent Lookup Database Mapping(s) Comment Checks equipment_code Text(60) PK Y dt_equipment.equipment_code The unique identifier of the equipment. Allow value to exist in either the database or Equipment section. equipment_type Text(30) rt_equipment_type.equipment_type dt_equipment.equipment_type The type of equipment. equipment_desc Text(255) dt_equipment.equipment_desc The description of the equipment. sys_loc_code Text(20) dt_equipment.sys_loc_code The location at the equipment is
permanently installed, used, or with which it is associated, if applicable. model_number Text(50) dt_equipment.model_number The model number of the equipment. catalog_number Text(50) dt_equipment.catalog_number The catalog number of the equipment. manufacturer Text(50) dt_equipment.manufacturer The manufacturer of the equipment. owner Text(50) dt_equipment.owner The owner of the equipment. operation_status Text(20) dt_equipment.operation_status The operational status of the equipment. install_date DateTime dt_equipment.install_date The date and time of equipment installation. last_service_date DateTime dt_equipment.last_service_date The date and time the equipment was last serviced. next_service_date DateTime dt_equipment.next_service_date The date and time the equipment is scheduled to be serviced next. purchase_date DateTime dt_equipment.purchase_date The date and time of equipment purchase. purchase_price Text(20) dt_equipment.purchase_price The cost of the equipment. material Text(50) dt_equipment.material The main material of the equipment.
size Text(20) dt_equipment.size The size of the equipment. size_unit Text(15) rt_unit.unit_code dt_equipment.size_unit The unit of measure of the equipment size. remark Text(2000) dt_equipment.remark Any additional information about the equipment. EquipmentParameter_v1 Field Name Data Type Key Required Default Parent Lookup Database Mapping(s) Comment Checks equipment_code Text(60) PK Y dt_equipment.equipment_code dt_equipment_parameter.equipment_code The unique identifier of the equipment. Allow value to exist in either the database or Equipment section. param_code Text(20) PK Y rt_equipment_param_type.param_code dt_equipment_parameter.param_code The equipment parameter. measurement_date DateTime PK dt_equipment_parameter.measurement_date The date and time of parameter measurement. param_value Text(20) dt_equipment_parameter.param_value The value of the parameter measured. person_name Text(20) dt_equipment_parameter.person_name The name of the person measuring the parameter. remark Text(2000) dt_equipment_parameter.remark Any additional information if necessary. fld_qualifier Text(20) dt_equipment_parameter.fld_qualifier qualifier if required. fld_qualifier_note Text(255) dt_equipment_parameter.fld_qualifier_note Field qualifier note if required. Files Field Name Data Type Key Required Default Parent Lookup Database Mapping(s) Comment Checks file_name Text(255) PK Y dt_file.file_name The name of the file. file_type Text(20) Y rt_file_type.file_type dt_file.file_type The type of the file, for example ".jpg" or ".pdf". file_date DateTime The date and time of the file. title Text(255) dt_file.title The title of the file. author Text(255) dt_file.author The author of the file. confidential_yn Text(1) (Enumeration: yes_no_values) dt_file.confidential_yn Y" if the file is confidential, "N" if the file is not confidential.
ground surface of the drilling activity. end_depth Numeric dt_drill_activity.end_depth The end depth below ground surface of the drilling activity. drill_start_date DateTime dt_drill_activity.start_date The date and time the drilling activity drill_end_date DateTime dt_drill_activity.end_date The date and time the drilling activity ended. diameter Numeric dt_drill_activity.diameter The diameter of the boring. diameter_unit Text(15) rt_unit.unit_code dt_drill_activity.diameter_unit The unit of measure of the diameter. drill_method Text(50) dt_drill_activity.drill_method The drilling method used. fluid Text(50) dt_drill_activity.fluid The description of fluid used during the drilling activity. viscosity Text(50) dt_drill_activity.viscosity The viscosity of the drilling fluid. hammer_wt Text(50) dt_drill_activity.hammer_wt The weight of hammer used during the drilling activity. hammer_fall Text(50) dt_drill_activity.hammer_fall The distance of hammer fall during the drilling activity. hammer_desc Text(50) dt_drill_activity.hammer_desc The description of the hammer used during the drilling activity.
lift_mechanism Text(50) dt_drill_activity.lift_mechanism The type of mechanism used to lift the hammer. new_yn Text(1) (Enumeration: yes_no_values) dt_drill_activity.new_yn Y" if this is a new drilling activity at the location or boring, "N" if not. repair_yn Text(1) (Enumeration: yes_no_values) dt_drill_activity.repair_yn Y" if the purpose of the drilling activity is to repair an existing boring, "N" if not. deepen_yn Text(1) (Enumeration: yes_no_values) dt_drill_activity.deepen_yn Y" if the purpose of the drilling activity is to deepen an existing boring, "N" if not. abandon_yn Text(1) (Enumeration: yes_no_values) dt_drill_activity.abandon_yn Y" if the boring has been abandoned, "N" if not. replace_yn Text(1) (Enumeration: yes_no_values) dt_drill_activity.replace_yn Y" if the purpose of the drilling activity is to replace an existing boring, "N" if not. public_yn Text(1) (Enumeration: yes_no_values) dt_drill_activity.public_yn Y" if the drilled location is for public use, "N" if not. purpose Text(70) dt_drill_activity.purpose The descriptive purpose of the drilling activity. rig_desc Text(50) dt_drill_activity.rig_desc The description of the drilling rig.
custom_field_5 Text(255) dt_lithology.custom_field_5 A custom field. Well_v1 Field Name Data Type Key Required Default Parent Lookup Database Mapping(s) Comment Checks sys_loc_code Text(20) PK Y Location_v1.sys_loc_code dt_well.sys_loc_code The unique identifier of the location. Must be a valid code for the facility and reported value in the sys_loc_code field of the Location section. well_id Text(30) dt_well.well_id The ID of the well. well_desc Text(255) dt_well.custom_field_1 The description of the well. well_owner Text(50) dt_well.well_owner The name of the well well_purpose Text(20) dt_well.well_purpose The purpose of the well. well_status Text(20) dt_well.well_status The status of the well. top_casing_elev Numeric dt_well.top_casing_elev The top of casing elevation of the well. depth_of_well Numeric dt_well.depth_of_well The total depth of the well below ground surface. depth_unit Text(15) rt_unit.unit_code dt_well.depth_unit The unit of measurement of the depth. depth_measure_method Text(20) dt_well.depth_measure_method The method of depth measurement. stickup_height Text(8) dt_well.stickup_height The height of the casing above ground surface. stickup_unit Text(15) rt_unit.unit_code dt_well.stickup_unit The unit of measure of the stickup height. sump_length Text(20) dt_well.sump_length The length of the sump. sump_unit Text(15) rt_unit.unit_code dt_well.sump_unit The unit of measure of
the sump length. installation_date DateTime dt_well.installation_date The date and time of well installation. construct_start_date DateTime dt_well.construct_start_date The date and time the well construction began. construct_complete_date DateTime dt_well.construct_complete_date The date and time the well construction finished. construct_contractor Text(40) rt_company.company_code rt_company.company_name dt_well.construct_contractor The name of the contractor that installed well. pump_type Text(20) dt_well.pump_type The type of pump used at the well, such as centrifugal, propeller, jet, helical, rotary, etc. pump_capacity Text(6) dt_well.pump_capacity The capacity of the pump. pump_unit Text(15) rt_unit.unit_code dt_well.pump_unit The unit of measure of the pump capacity and yield. pump_yield Text(6) dt_well.pump_yield The yield of the pump. pump_yield_method Text(20) dt_well.pump_yield_method The method used for the pump yield. weep_hole Text(1) (Enumeration: yes_no_values) dt_well.weep_hole Y" if the well has a weep hole, "N" if not. head_configuration Text(50) dt_well.head_configuration The well head configuration. access_port_yn Text(1) (Enumeration: yes_no_values) dt_well.access_port_yn Y" if the well has an access port, "N" if not. casing_joint_type Text(50) dt_well.casing_joint_type The type of casing joint, such as threaded, flush, or solvent welded. perforator_used Text(50) dt_well.perforator_used The description of well perforation, such as slotted,
screen_type Text(15) dt_well_segment.screen_type The type of screen. material_quantity Text(20) dt_well_segment.material_quantity The quantity of material used. Applicable to annular seal/fill material. material_density Text(20) dt_well_segment.material_density The density of the material used. remark Text(2000) dt_well_segment.remark Any additional information about the well segment. WaterLevel_v1 Field Name Data Type Key Required Default Parent Lookup Database Mapping(s) Comment Checks sys_loc_code Text(20) PK Y Location_v1.sys_loc_code dt_water_level.sys_loc_code The unique identifier of the location. Must be a valid code for the facility and reported value in the sys_loc_code field of the Location section. measurement_date DateTime PK Y dt_water_level.measurement_date The date and time of the water level measurement. equipment_code Text(60) dt_equipment.equipment_code dt_water_level.equipment_code The unique identifier of the equipment used to measure the water level. historical_reference_elev Numeric dt_water_level.historical_reference_elev The historical reference elevation value. Used for the elevation of
past reference points. water_level_depth Numeric dt_water_level.water_level_depth The of the water level. water_level_elev Numeric dt_water_level.water_level_elev The elevation of the water level. corrected_depth Numeric dt_water_level.corrected_depth The depth of the water level after any necessary corrections. For example, corrections may be necessary if free product was encountered. corrected_elev Numeric dt_water_level.corrected_elevation The elevation of the water level after any necessary corrections. For example, corrections may be necessary if free product was encountered. measured_depth_of_well Numeric dt_water_level.measured_depth_of_well The depth below ground surface to the bottom of the well. depth_unit Text(15) rt_unit.unit_code dt_water_level.depth_unit The unit of measure of the depths. technician Text(50) dt_water_level.technician The name of the technician measuring the water level. dry_indicator_yn Text(1) (Enumeration: yes_no_values) dt_water_level.dry_indicator_yn Y" if the well is dry, "N" if not. measurement_method Text(20) dt_water_level.measurement_method The method used to measure the level. batch_number Text(10) dt_water_level.batch_number The batch of the water
level measurement. dip_or_elevation Text(9) Y dip (Enumeration: dip_or_elevation) dt_water_level.dip_or_elevation dip" if the water level is below the measurement datum, "elevation" if the water level is above the measurement datum (i.e. an artesian well). remark Text(2000) dt_water_level.remark Any additional information the water level measurement. lnapl_cas_rn Text(15) rt_analyte.cas_rn dt_water_level.lnapl_cas_rn The identifier of the LNAPL analyte. lnapl_depth Numeric dt_water_level.lnapl_depth The depth to LNAPL. dnapl_cas_rn Text(15) rt_analyte.cas_rn dt_water_level.dnapl_cas_rn The identifier of the DNAPL analyte. dnapl_depth Numeric dt_water_level.dnapl_depth The to DNAPL. task_code Text(40) dt_task.task_code dt_water_level.task_code The unique identifier of the task associated with the water level measurement. approval_code Text(10) rt_valid_code.accept_code dt_water_level.approval_code The approval code for the level measurement. custom_field_1 Text(255) dt_water_level.custom_field_1 A custom custom_field_2 Text(255) dt_water_level.custom_field_2 A custom field. custom_field_3 Text(255) dt_water_level.custom_field_3 A custom field. custom_field_4 Text(255) dt_water_level.custom_field_4 A custom field. custom_field_5 Text(255) dt_water_level.custom_field_5 A custom field.
correction necessary to account for the effects of sample matrix. This is important to remember especially for risk assessments and highly contaminated samples. reporting_detection_limit Numeric dt_result.reporting_detection_limit The concentration level above which results can be quantified with confidence. It must reflect conditions such as dilution factors and moisture content. Required for all results for which such a limit is appropriate. The reporting_detection_limit column must be reported as the detection limit. Reporting_detection_limit cannot be negative unless one of the radiological fields (minimum_detectable_conc, counting_error, uncertainty, critical_value) are populated. If method_detection_limit, reporting_detection_limit, or quantitation_limit is populated then detection_limit_unit is required. If detect_flag='N' and result_type_code='SC', 'TRG' or 'TIC' then reporting_detection_limit is required. quantitation_limit Text(20) dt_result.quantitation_limit The quantitation limit refers to a minimum concentration of an analyte that can be measured within specified limits of precision and accuracy. It is generally 5-10 times the detection limit. Thus, when quantitation limits are used as reporting limits, the laboratory is saying that the analyte is not present in a sufficient amount to be reliably quantified (i.e. at a concentration above the quantitation limit). It may be present and even positively identified or "seen" at a lower concentration. If method_detection_limit, reporting_detection_limit, or quantitation_limit is populated then detection_limit_unit is required. result_unit Text(15) rt_unit.unit_code dt_result.result_unit The unit of measurement of the result value. If result_value is populated then result_unit is required.