Human health risk assessment of heavy metals via consumption of contaminated vegetables collected from different irrigation sources in Lahore,Pakistan

Soil pollution with heavy metals due to discharge of untreated urban and industrial wastewater is a major threat to ecological integrity and human well-being. The presenting study aimed to determine human health risks associated via food chain contamination of heavy metals routing from irrigation of urban and industrial wastewater. Irrigated water, soil and vegetables were analyzed for Cr²⁺, Co²⁺, Ni²⁺, Cu²⁺, Pb²⁺, Cd²⁺, Mn²⁺ and Zn²⁺; transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Cr²⁺, Pb²⁺ and Cd²⁺ in vegetables cultivated by wastewater exceeded the permissible limits (European Union, 2002) while TF was lower for all metals except Co²⁺ and HRI was found to be maximum for Spinacia oleracea (2.42 mg/kg) and Brassica campestris (2.22 mg/kg) cultivated by wastewater. S. oleracea, B. campestris, Coriandrum sativum posed a severe health risk with respect to Cd and Mn.     

Assessment of trace elements characteristics and human health risk of exposure to ambient PM2.5 in Hangzhou,China

A method for simultaneously determining the trace elements in particulate matter (PM) (PM2.5) by inductively coupled plasma mass spectrometry was established. The PM2.5-loaded filter samples were digested under the optimised conditions including a mixture of HNO₃–HCl–HF with ultrasonication proceeding at 70°C for 2 h. Recoveries of 90.83–103.33% were achieved for 20 elements (Co, Sr, Ag, Cd, Sb, La, Ce, Sm, W etc.) in NIST standard reference material 1648a (urban PM). PM2.5 samples were collected at urban site in Hangzhou from August 2015 to November 2015. PM2.5 concentrations of 15% sampling days exceeded the daily limitation and the mean concentrations of PM2.5 from August to November reached the 66.4% of the limitation. PM2.5 concentrations in summer were higher than that in autumn. The concentration of Zn was highest, following with Al, Pb, Mn, Cu and As. Significant enrichment was observed in Mn, Zn, Pb, Ag, V, Ni, Cu, As, Se, Hg, Co, Cd and W, which was probably induced by vehicular exhaust, oil and residual fuel combustion and industrial emissions. The daily mass concentrations of PM2.5 and elements fluctuated significantly. Rainfall could significantly reduce the concentration of Ti, Mn, Cu, Zn, As, Se, Hg, Sr, Ag, Cd, Sb, La, Ce, Sm and Pb, and the risk levels of carcinogenic elements and non-carcinogenic elements in rain day were significantly lower (43.7–81.4%) than those in non-rain day. The risk levels of Co, Cd and As could lead to adverse health outcomes through the respiratory system, which should deserve more attention, while the risk levels of Ni and non-carcinogenic elements (Hg, Mn, Cu, Zn, Pb, V) were under average risk acceptance.     

Risk assessment, remedial decisions and the challenge to protect public health: the perchlorate case study

While scientists have a responsibility to defer judgment in the absence of conclusive data, public health and ecological protection require that government regulators make decisions based on available information. The risk assessment paradigm has evolved to help risk managers balance risks to public health with the cost of pollution control and remediation. Risk assessments are designed to be reasonably protective of public health, however the time and money required to develop and evaluate a robust scientific database can significantly delay regulatory action while exposures continue. The federal assessment of perchlorate, a component of rocket fuel and a thyroid toxicant, is presented here as a case study that demonstrates some of the limitations of risk assessment in protecting public health. Perchlorate was detected in a city well field that lies beneath a military training range at Aberdeen Proving Ground, a U.S. Army garrison in Maryland. Cleanup was put on hold, pending promulgation of a national drinking water standard for perchlorate. This case study (1) illustrates the challenge of preventing chemical exposures in the absence of promulgated standards, and (2) makes recommendations for approaches to preventing exposures to chemicals of unknown, or uncertain toxicity before they occur.     

A new simple,low-cost approach for generation of the PM10 fraction from soil and related materials: Application to human health risk assessment

A new simple, robust and low-cost wet laboratory method for the generation of the <10 μm (PM₁₀) particle size fraction is reported. A sedimentation method is directly compared with a centrifugation method for generation of the PM₁₀ fraction. Both approaches are based on an integrated form of Stokes’ law. Subsequently the sedimentation method was adopted. The results from the sedimentation method were corroborated using particle size distribution measurements. This approach for the generation of the PM₁₀ fraction was applied to soil and mine waste samples from Mitrovica, Kosovo as part of an investigation in to the human risk assessment from inhalation of the PM₁₀ fraction containing potentially harmful elements (PHEs). The average daily dose for Cd from the inhalation of suspended soil particles was calculated to be 0.021 and 0.010 μg kg⁻¹_BW d⁻¹ for a child and an adult, respectively. This corresponded to an inhalation dose of 0.50 and 0.70 μg Cd d⁻¹ for a child (20 kg) and an adult (70 kg), respectively.