It is the first line of defense of our body against any organism. convenience, we assume a user with a skin surface area of. 1.8 m2 and a mass of 70 kg. For the average adult human, the skin has a surface area of between 1.5–2.0 square metres (16–22 sq ft). Contact Us to ask a question, provide feedback, or report a problem. Also called hypodermis, this layer helps in regula­tion of body temperature and provides cushioning to the skin. It is a single layer of cuboidal and columnar cells from which new epidermal cells are con­stantly being produced, which later become cells of more superficial layers. They might also describe a receptor population’s activities that may affect exposure and the timeframe over which exposure occurs. Surface area of a cube: A = 6a², where a is the side length. is the way that a contaminant enters an individual or population after contact (IPCS, 2004). 1. The internal (or absorbed) dermal dose is determined by the rate at which the contaminant is absorbed, and this will be a function of contaminant properties. Receptors could come into contact with contaminants in soil and dust that have settled on carpets, floors, clothing, counter tops, or other surfaces. ... 1991 to 2000. A number of resources are available to assist in these modeling efforts. Skin areas One hand 420, two hands 840 cm2 Surface area/body wt ratio SA/BW (cm2/kg) See Table 1 Not used Skin loading, adherence factor Constant at 0.7 (low) or 2.1 (high) mg/cm2-event for liquids Amount retained on skin Q (g/cm2-event); based on experimental film thickness data Not used Not used Dermal absorption 100% absorption of substance available to skin Permeability coefficient Kp (cm/h) … Below are the body surface area formula by Dr’s Mosteller, DuBois and DuBois, Haycock and Boyd. Module 1 - water (e.g., during bathing, washing, swimming); outdoor soil or dust (e.g., during recreational, gardening, or construction-related activities); and. inches, feet, mm, cm. Typically, exposure occurs by one of three exposure routes-inhalation, ingestion, or dermal. For dermal contact with solids (e.g., soil, sediment), the concentration of contaminant contacting the skin is a function of the concentration of contaminant in the solid material (e.g., soil) and the amount of solid that adheres to the skin per unit surface area. (Assume a normal body temperature of 37 ∘C for the temperature of the interior.) Keratin is a very important constituent as it is a type of insoluble fibrous protein that helps to protect the body. The total area of the body surface covered by the skin is about 2m 2 in adults, and the skin thickness varies between 0-3 mm and 3mm. This layer helps in protection against heat, chemicals, light, and microorganisms. Lipoma Example picture of lipoma. Flux, or the amount of contaminant that penetrates per unit of time, has been mathematically described by Fick’s Law of Diffusion for membranes. It is a layer of well-defined flat cells, which have their own nucleus and also granules and con­tains a substance called keratohyalin, which later becomes keratin. Temporal parameters in the dose equation include: Exposure parameter inputs (e.g., dermal contact factors, body weights, and relevant patterns of behavior such as timeframe of exposure) can be obtained from the Handbook. Other activity-specific factors that might be relevant for assessing exposures with contaminants via dermal contact are available in Chapter 16 of the Handbook. The use of the values in the guidance will promote … The Exposure Factors Tab of the Indirect Estimation Module provides links to data on other factors. Another dermal factor is the adherence factor (AF; mg/cm2), which represents the quantity of soil or solids that may adhere to the skin surface after contact. Depending on the scenario, total body surface area or surface areas of specific body parts may be appropriate.