J. Cosmet. Sci., 66, 233–246 (July/August 2015) 233 Human health risk assessment of heavy metals in cosmetics in Nigeria JOHN K. NDUKA, ISAAC O. ODIBA, ORISH E. ORISAKWE, LINDA D. UKAEBGU, CHINWETUTO SOKAIBE, and NNAEMEKA A. UDOWELLE, Pure and Industrial Chemistry Department, Environmental Chemistry and Toxicology Research Unit, Nnamdi Azikiwe University, Awka, Anambra State (J.K.N., N.A.U.), Department of Chemistry, Alvan Ikoku Federal College of Education, Owerri Imo State (I.O.O, C.S.), and Department of Experimental Pharmacology, Toxicology Unit, Faculty of Pharmacy, University of Port Harcourt Rivers State (O.E.O), Nigeria. Accepted for publication April 24, 2015. Synopsis Forty two different cosmetics were purchased from supermarkets and cosmetic shops within Onitsha Main Market and Eke-Awka markets in Anambra, Nigeria. Of the cosmetics, 16% were locally manufactured in Nigeria while 83.33% were imported into Nigeria. The cosmetics were ashed before digestion and fi ltration. The fi ltrates were assayed for lead, cadmium, manganese, nickel, chromium, mercury, and arsenic with atomic absorption spectrophotometry at 205 Å. The health risk assessment methods developed by the United States Environmental Protection Agency were employed to explore the potential human health risk of heavy metals in cosmetics. About 61.91% of the cosmetic samples contained lead with concentration in the range of 0.10–42.12 mg/kg. Cadmium levels of the cosmetics ranged from 0.01 to 1.32 mg/kg, manganese from 0.02 to 67.65 mg/kg, nickel from 0.05 to 17.34 mg/kg, chromium from 0.11 to 9.81 mg/kg, mercury from 0.003 to 0.07 mg/kg, and arsenic from 0.002 to 0.005 mg/kg. Although the target hazard quotients and the hazard indices suggest a measure of safety, cosmetics may add to the body burden of potential toxic metals after chronic exposure. INTRODUCTION Cosmetics have formed an integral part of human civilization as evidenced by its use even by primitive men to clean, beautify, and alter their appearance (1). Certain chem- icals that are a part of cosmetic formulations have been found to be harmful, and the usage of cosmetics products containing such chemical portends danger for human health. Notable examples of such chemicals are heavy metals. Heavy metals such as lead, cadmium, manganese, nickel, chromium, mercury, and arsenic are found in a wide Address all correspondence to Orish E. Orisakwe at orishebere@gmail.com.

JOURNAL OF COSMETIC SCIENCE 234 variety of cosmetic products (2–6). Reasons for their presence in cosmetic products include their existence as components of the major raw materials used in cosmetics products manufacture (5) and their deliberate inclusion as ingredients (4). Exposure to metals has been associated with health concerns including reproductive, immune, and nervous system toxicity (7). Lead is a potential impurity in many color cosmetics (7) and may be absorbed into the body by ingestion, inhalation, and through the skin (8,9). Lead is a well-known and proven neurotoxin associated with learning, language, and behavioral problems (10). Cadmium, a deep yellow to orange pigment whose presence in cosmetic products is at- tributed to its color property (11), is highly toxic to humans and is listed by the United States Environmental Protection Agency (USEPA) as one of the priority pollutant metals (12). Trace amounts of manganese are essential for animals but in large quantities, the metal may be toxic. Chronic inhalation of metal dust or fumes can cause manganism, a nonfatal disease that affects the central nervous system. The symptoms are mental disor- der and disturbance in speech (13). Nickel on contact with the skin can cause dermatitis and a type of chronic eczema known as “nickel itch” caused by hypersensitivity reactions (13). Chromium in its hexavalent form is corrosive to the skin, carcinogenic (14), and causes denaturation and precipitation of tissue proteins. Mercury can be absorbed through the skin and mucous membranes and its salts inhibit the formation of melanin (4). Arse- nic is notoriously poisonous to multicellular life, and epidemiological evidence shows a dose–dependent connection between chronic arsenic exposure and various forms of can- cer, in particular when other risk factors, such as cigarette smoking, are present. These effects have been demonstrated to persist below 50 ppb (15). Although many studies exist on the presence of these elements in cosmetic products, human health assessments are scarce. This study is a risk assessment of potential toxic metals in cosmetics com- monly used in Nigeria. EXPERIMENTAL MATERIALS AND METHODS In August 2013, using market basket protocol, 42 brands of cosmetic samples consisting of 16 facial cosmetics, 6 soaps, 1 shower gel, 12 emulsions, 2 underarm cosmetics, 3 nail cosmetics, and 2 perfumes were purchased from supermarkets and cosmetic shops in Onitsha and Awka in Anambra State, Nigeria, and used in the study. The samples were ashed and digested in Tefl on labware that had been cleaned in a high-effi ciency particu- late air fi ltered (class 100), trace-metal-clean laboratory to minimize contamination. This protocol involved sequential cleaning of the labware in a series of baths in solutions (1 week each) and rinses (fi ve per solution) in a three-step order, namely a detergent solu- tion bath and deionized water rinses, then 6 N HCl (reagent grade) solution bath and ultrapure water rinses, and fi nally 7.5 N HNO3 (trace metal grade) solution bath and ultrapure water rinses. The labware was then air-dried in a polypropylene laminar airfl ow- exhausting hood. A dry ashing method was used by adding 30 ml of each sample into a conical fl ask and heating on a hot plate at 200°C for 45 min and then in a furnace at 500°C until the volume was drastically reduced to near dryness. Digestion was per- formed by addition of 10 ml concentrated aqua regia (HCl:HNO3, 3:1) this was then