Iwegbue Chukwujindu M A, Oliseyenum Ejiro C, Martincigh Bice S
Department of Chemistry, Delta State University, P.M.B. 1, Abraka, Nigeria.
School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban, 4000, South Africa.
Environ Sci Pollut Res Int. 2017 Jun;24(16):14040-14059. doi: 10.1007/s11356-017-8609-1. Epub 2017 Apr 13.
Concentrations of metals in household dust samples from rural, semi-urban and urban zones of the Niger Delta in Nigeria were measured during both 2009 and 2014 with the aim of providing information on changes in the concentrations, distribution patterns, sources and risks of metals in these zones. The concentrations of metals in the dust samples were quantified by using inductively coupled plasma atomic emission spectrophotometry (ICP-AES) after digestion with aqua regia. The measured concentrations (mg kg) of metals in the three zones within the study periods were as follows: <LOQ-21.2; <LOQ-182; 7.90-265; <LOQ-117; <LOQ-471; 3.37-2310; 0.35-7.9; 4.25-365; 6.78-61,600; 219-37,700; and 1180-18,000 for Cd, Pb, Ba, Cr, Ni, Cu, Co, Mn, Zn, Fe and Al, respectively. The results from the two periods indicate significant changes in the concentrations, distribution patterns and risk factors which reflects a deterioration of the quality of the household environment over this time span. The hazard index (HI) values calculated for children were greater than 1 indicating significant non-cancer risks for these subjects in these areas. The HI values for adults were less than 1 and consequently do not pose a significant risk. The carcinogenic risk levels for exposure to metals for both adults and children in these zones were below the range specified as safe by the US EPA (×10 and ×10) thereby indicating a low cancer risk. The sources of metals in household dust from these zones include emissions from industries, traffic, artisanal workshops and releases from household furniture, metal-based fittings, metal roofing and pesticides.
2009年和2014年期间，对尼日利亚尼日尔三角洲农村、半城市和城市地区家庭灰尘样本中的金属浓度进行了测量，目的是提供这些地区金属浓度、分布模式、来源和风险变化的信息。灰尘样本中的金属浓度在经王水消解后，采用电感耦合等离子体原子发射光谱法（ICP-AES）进行定量。研究期间三个区域内金属的测量浓度（mg/kg）如下：镉为<检测限-21.2；铅为<检测限-182；钡为7.90-265；铬为<检测限-117；镍为<检测限-471；铜为3.37-2310；钴为0.35-7.9；锰为4.25-365；锌为6.78-61,600；铁为219-37,700；铝为1180-18,000。两个时期的结果表明，浓度、分布模式和风险因素发生了显著变化，这反映了在此时间段内家庭环境质量的恶化。为儿童计算的危害指数（HI）值大于1，表明这些地区的这些儿童存在显著的非癌症风险。成人的HI值小于1，因此不存在显著风险。这些区域成人和儿童接触金属的致癌风险水平低于美国环境保护局规定的安全范围（×10和×10），从而表明癌症风险较低。这些区域家庭灰尘中金属的来源包括工业排放、交通排放、手工作坊排放以及家用家具、金属配件、金属屋顶和农药的释放。
