Section 40.0933 - Identification of Applicable Soil CategoriesSoil shall be classified as either category S-1, S-2 or S-3. The site, receptor and exposure information identified in 310 CMR 40.0904 through 310 CMR 40.0929, considering both the current and reasonably foreseeable Site Activities and Uses identified in 310 CMR 40.0923, shall be used in conjunction with the criteria listed below to categorize the soil.
(1) The soil categories shall be applicable to specific volumes of soil which shall be described in written and graphic form in the documentation of the Risk Characterization.(2) The three soil categories describe a range of the potential for exposure to that soil: Category S-1 soils are associated with the highest potential for exposure, Category S-3 soils have the lowest potential for exposure. While one and only one category is applicable to a specified volume of soil, soils in different areas of a disposal site may be classified in different categories, depending upon their exposure potential.(3) The Table in 310 CMR 40.0933(9) contains a matrix summarizing the criteria used to categorize soil.(4) For the purpose of soil categorization, the potential for exposure is described by a qualitative analysis of the accessibility of the soil in combination with the information about the Site Activities and Uses determined pursuant to 310 CMR 40.0923. The following definitions shall be used to describe exposure potential for the purposes of categorizing soil: (a)Frequency of Use shall indicate how often a receptor makes use of, or has access to, the disposal site. Receptor access to and use of the areas around the disposal site are often strong indicators of potential site access and thus should be considered in determining frequency of use for the site under investigation. Frequency of use shall be described as either "High", "Low" or "Not Present", using the following criteria: 1. Children's frequency of use shall be characterized as high if: a. any children reside, attend school or attend day care at the disposal site; orb. large numbers of children visit the disposal site, regardless of any one child's frequency of visitation.2. Adults' frequency of use shall be characterized as high when they reside at the disposal site, or when they work at the disposal site on a continuing basis [ i.e., full days or shifts of eight or more hours per day on a continuing basis].3. Children's or adults' frequency of use shall be characterized as low when they are present at the disposal site, but only as infrequent visitors; or when workers are present at the disposal site for only short periods of time [ i.e., less than two hours per day on a continuing basis, or for full days or shifts on a sporadic basis].4. It shall be presumed that children may be present at the disposal site, unless it can be demonstrated that access by children younger than 15 years old is specifically restricted or that such children are highly unlikely to be present, in which case children may be considered to be "Not Present". Disposal sites which are residential properties shall presume the presence of children, unless there is clear and convincing evidence to the contrary.5. The frequency of use for activities not described above shall be characterized in the documentation of the Risk Characterization as either high or low.(b)Intensity of use shall describe the nature of the Site Activities and Uses which could potentially result in exposure to the receptor. Intensity of use shall be described as either "High" or "Low", using the following criteria: 1. Site Activities and Uses which have the potential to disturb soil and thus result in either direct contact with the soil itself or inhalation of soil-derived dust shall be characterized as high intensity use. Examples of such activities include, without limitation, gardening, digging, and recreational sports.2. Passive activities which do not disturb the soil, such as walking, shopping, and bird watching shall be characterized as low intensity use.3. The intensity of use for each identified Site Activity and Use shall be characterized in the documentation of the Risk Characterization as either high or low with appropriate justification.(c)Accessibility of the soil to potential receptors shall be characterized as either "accessible", "potentially accessible", or "isolated" using the following criteria: 1. Soil shall be characterized as "accessible" if it is located less than three feet below the surface, and the surface is not completely covered by pavement. For buildings having earthen floors, the floor shall be considered as the soil surface.2. Soil shall be characterized as "potentially accessible" if it is located at a depth of three feet to 15 feet below the surface (with or without pavement), or if the soil is located less than three feet from the surface in an area completely paved.3. Soil shall be characterized as "isolated" if it is located at a depth greater than 15 feet below the surface, or if the soil is covered completely by a building or other permanent structure which does not have earthen floors, regardless of depth. Soil located at a depth greater than three feet below the earthen floor of a building or other permanent structure shall also be characterized as "isolated".(5)Category S-1. Soil shall be classified as category S-1 if either: (a) the soil of concern is accessible, pursuant to 310 CMR 40.0933(4)(c)1., and either: 1. the soil is currently used for growing fruits or vegetables for human consumption or, if it is reasonably foreseeable, that the soil may be put to such use; or2. a child's frequency or intensity of use is considered to be high, pursuant to 310 CMR 40.0933(4)(a) and (b); or3. an adult's frequency and intensity of use are both considered to be high, pursuant to 310 CMR 40.0933(4)(a) and (b); or(b) the soil is potentially accessible, pursuant to 310 CMR 40.0933(4)(c)2., and a child's frequency and intensity of use are both considered to be high, pursuant to 310 CMR 40.0933(4)(a) and (b).(6)Category S-2. Soil shall be classified as category S-2 if either: (a) the soil is accessible, pursuant to 310 CMR 40.0933(4)(c)1.; and 1. a child's frequency and intensity of use are both considered to be low, pursuant to 310 CMR 40.0933(4)(a) and (b); or2. children are not present at the disposal site and either (but not both) the adults' frequency or intensity of use is considered to be high, pursuant to 310 CMR 40.0933(4)(a) and (b); or(b) the soil is potentially accessible, pursuant to 310 CMR 40.0933(4)(c)2.; and1. either (but not both) a child's frequency or intensity of use is considered to be high, pursuant to 310 CMR 40.0933(4)(a) and (b); or2. children are not present at the disposal site and an adult's frequency and intensity of use are both considered to be high, pursuant to 310 CMR 40.0933(4)(a) and (b).(7)Category S-3. Soil shall be classified as category S-3 if either: (a) the soil is accessible, pursuant to 310 CMR 40.0933(4)(c) 1., and children are not present at the disposal site and an adult's frequency and intensity of use are both considered to be low, pursuant to 310 CMR 40.0933(4)(a) and (b); or(b) the soil is potentially accessible pursuant to 310 CMR 40.0933(4)(c)2.; and1. a child's frequency and intensity of use are both considered to be low, pursuant to 310 CMR 40.0933(4)(a) and (b); or2. a demonstration has been made that children are not present at the disposal site, and either an adult's frequency or intensity of use is considered to be low, pursuant to 310 CMR 40.0933(4)(a) and (b); or(c) the soil is isolated pursuant to 310 CMR 40.0933(4)(c)3., regardless of any receptor's frequency or intensity of use.(8) Whenever and wherever reasonable doubts exist over the selection of the appropriate soil category, the soil category associated with the highest exposure potential (among the soil categories being considered) shall be selected.(9) Table listed in 310 CMR 40.0933(9) contains the Soil Category Selection Matrix. Table 40.933(9)
SOIL CATEGORY SELECTION MATRIX - HUMAN EXPOSURE POTENTIAL
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Amended by Mass Register Issue 1503, eff. 3/1/2024.Amended by Mass Register Issue S1516, eff. 3/1/2024.