In vitro bioaccessibility of potentially toxic metals (PTMs) in Baoji urban soil (NW China) from different functional areas and its implication for health risk assessment.

In order to better understand both the conceptual and operational aspects of bioaccessibility and phytobioavailability of PTMs (Co, Cr, Cu, Li, Mn, Ni, Pb, Zn) in different urban soils, a total of 30 soil samples from agricultural region, entertainment district, education area, traffic area, residential area and industrial area (IA) in Baoji urban city (NW China) were collected and the bioaccessibility and phytobioavailability were measured by multi-in vitro models of PBET, SBET, citric acid leaching and Tessier sequential extraction procedure, respectively. The suitable in vitro measurement of bioaccessibility and phytobioavailability for each PTM was selected and would be reliably applied for health risk assessment. The results indicated that the bioaccessibility and phytobioavailability for each PTM evaluated by in vitro models depended on PTM total concentration and anthropologic activity influence. The health risks associated with bioaccessibility of PTMs exposure showed that the carcinogenic and non-carcinogenic risks in all areas for children and adults were below the threshold or acceptable risk levels except lead exposure on children in IA, indicating there were more health risks to the children in than that in other functional areas. It was worth that the highest observation of Pb in IA would strongly correlate with lead-acid battery industries, which the emissions would influence on the occurrences of Pb distributing in the other functional areas, which were supported from the analysis results of XPS. Therefore, the continuous monitoring and attention to the health risk of inhabitants in different functional areas should be paid.

Use of a Survey to Assess the Environmental Exposure and Family Perception to Lead in Children (<6 Years) in Four Valley Cities, Northwestern China.

With the growth of industry, the extensive use of lead, and urban expansion in Northwestern Valley Cities (NVC) China, there is probable reason for presuming an increasing risk of lead exposure. However, little is known about the lead exposure of children less than 6 years old in NVC. As a first investigation, this study uses a survey to systematically determine the influences of various risk factors within the family environment, parents' background, children's behavior, mother's behavior during pregnancy, and parental perception about children's blood lead (CBL). A total of 596 families were recruited from the general population in Urumqi, Lanzhou, Xining and Yan'an. Parents, and their children (<6 years old), were asked about the environment and behaviors which could possibly relate with lead exposure. The results indicated that in the typical NVC of China, children's environment and behavior, parents' education level, and mother's pregnancy behavior, were associated with potential CBL. It was noted that not all parents in NVC China recognized the importance of children's lead exposure. Therefore, children's health care and medical screening campaigns need to be designed to improve family's fundamental knowledge of lead hazards, associated health effects, and prevention in the NVC of China.

Multi-Elements in Source Water (Drinking and Surface Water) within Five Cities from the Semi-Arid and Arid Region, NW China: Occurrence, Spatial Distribution and Risk Assessment.

The purpose of this study was to identify the concentration of multi-elements (MEs) in source water (surface and drinking water) and assess their quality for sustainability. A total of 161 water samples including 88 tap drinking waters (DW) and 73 surface waters (SW) were collected from five cities in Xi'an, Yan'an, Xining, Lanzhou, and Urumqi in northwestern China. Eighteen parameters including pH, electrical conductivity (EC), total organic carbon (TOC) total nitrogen (TN), chemical compositions of anions (F-, Cl-, NO3-,HCO3-, SO42-), cations (NH4⁺, K⁺, Na⁺, Ca2+,Mg2+), and metals (lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu)) were analyzed in the first time at the five cities . The results showed that pH values and concentrations of Cl-, SO42-, Na⁺, K⁺, Ca2+, Mg2+ and Cd, Cr, Cu in DW were within the permissible limits of the Chinese Drinking Water Quality Criteria, whereas the concentrations of other ions (F-, NO3-, NH4⁺ and Pb) exceeded their permissible values. In terms of the SW, the concentrations of F-, Cl-, NO3-, SO42- were over the third range threshold i.e., water suitable for fishing and swimming of the Surface Water Quality Standards in China. The spatial distributions of most MEs in source water are similar, and there was no clear variation for all ions and metals. The metals in DW may be caused by water pipes, faucets and their fittings. The noncarcinogenic risk of metals in DW for local children are in decreasing order Cr > Cd > Pb > Cu. The carcinogenic risk from Cr exposure was at the acceptable level according to threshold of USEPA. Although the comprehensive index of potential ecological assessment of Cr, Cd, Pb and Cu in SW ranked at low risk level and was in the order of Huang River in Xining > Peaceful Canal in Urumqi > Yan River in Yan'an > Yellow River in Lanzhou, their adverse effects to ecology and human health at a low concentration in local semi-arid and arid areas should not be ignored in the long run.