Heavy Metal Pollution and Health Risk Assessment of Vegetable–Soil Systems of Facilities Irrigated with Wastewater in Northern China

Abstract

Soil pollution by heavy metals is a major concern in China and has received much attention in recent years. Aiming to investigate the status of heavy metal pollution and the safety of vegetables in the soil of wastewater-irrigated facilities, this study investigated the distribution and migration characteristics of heavy metals in vegetable–soil systems of facilities in a typical sewage irrigation area of the Xi River, Shenyang City, northern China. Health risks due to the fact of exposure to heavy metals in the vegetable soil of facilities and ingrown vegetables through different exposure pathways were evaluated. Spatial interpolation and a potential ecological risk assessment were applied to evaluate the soil quality. Bioaccumulation factors (BCFs) were used to analyze the absorption and transportation capacity of Cd, Cu, Pb, and Zn by different parts of different vegetables. The results showed that the average concentration of Cd exceeded the standard values by 1.82 times and accumulated by 11 times, suggesting that Cd poses the most severe pollution among the four metals in the soil of facilities in the Xi River sewage irrigation area. In the city, a significant accumulation of Cd in the soil was identified with different spatial distributions. Cd also contributed the most in terms of the estimated potential ecological risk index, while the impacts of the other three metals were relatively small. The concentrations of heavy metals were mostly lower than the limit set by the corresponding Chinese standards. Various BCFs were observed for the four metals in the order Cd > Zn > Cu > Pb. Vegetables also demonstrated different BCFs in the order of leaf vegetables > Rhizome vegetable > Solanaceae vegetable. The magnitude of the noncarcinogenic risk for all four heavy metals was less than one for all three exposure routes and did not cause significant noncarcinogenic health effects in humans. However, the carcinogenic risk of Cd from some vegetables via dietary intake was considered higher. Protection measures should be taken to implement better pollution control and land use planning.

Heavy metal(loid)s pollution indices and strategies for contaminants mitigation in crops near La Independencia community in Ponce Enriquez, southern Ecuador

“…En ese contexto, los índices de contaminación empleados en la valoración y categorización de la contaminación son herramientas útiles para la generación de estrategias y la toma de decisiones en la mitigación de los contaminantes [21]. Índices como el índice de metales en agua [22], el índice de carga de contaminación en suelos y sedimentos [23], [24], y el índice de bioacumulación en alimentos [25], son ampliamente utilizados en la evaluación de la contaminación.…”

“…El índice de bioacumulación (IBC) de metal(oid)es pesados en vegetales permite medir la capacidad que tienen los vegetales para absorber y acumular los contaminantes en sus tejidos [25], [39]. Este factor se calculó de acuerdo con la fórmula presentada en (4):…”

Occurrence, Distribution and Ecological Risk Assessment of Contaminants in Baiyangdian Lake, China

“…At first, the results of ecological risk research were mainly used to analyze the possibility of accidents and their consequences [2,3]. Later, ecological risk receptors were extended to human health, mainly to evaluate the possible harm and consequences of risk substances to human health [4,5]. In the 1990s, ecological risk receptors expanded from human health to the ecosystem itself and the multiple species in it, and an ecological risk assessment framework was eventually proposed [6,7].…”