Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW 2308, Australia; Co-operative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, Callaghan, NSW 2308, Australia.
Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW 2308, Australia; Co-operative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, Callaghan, NSW 2308, Australia.
Environ Int. 2017 Jan;98:18-34. doi: 10.1016/j.envint.2016.09.025. Epub 2016 Oct 14.
Risk-based approaches to managing contaminated land, rather than approaches based on complete contaminant removal, have gained acceptance as they are likely to be more feasible and cost effective. Risk-based approaches aim to minimise risks of exposure of a specified contaminant to humans. However, adopting a risk-based approach over alternative overly-conservative approaches requires that associated uncertainties in decision making are understood and minimised. Irrespective of the nature of contaminants, a critical uncertainty is whether there are potential risks associated with exposure to the residual contaminant fractions in soil to humans and other ecological receptors, and how they should be considered in the risk assessment process. This review focusing on hydrophobic organic contaminants (HOCs), especially polycyclic aromatic hydrocarbons (PAHs), suggests that there is significant uncertainty on the residual fractions of contaminants from risk perspectives. This is because very few studies have focused on understanding the desorption behaviour of HOCs, with few or no studies considering the influence of exposure-specific factors. In particular, it is not clear whether the exposure of soil-associated HOCs to gastrointestinal fluids and enzyme processes release bound residues. Although, in vitro models have been used to predict PAH bioaccessibility, and chemical extractions have been used to determine residual fractions in various soils, there are still doubts about what is actually being measured. Therefore it is not certain which bioaccessibility method currently represents the best choice, or provides the best estimate, of in vivo PAH bioavailability. It is suggested that the fate and behaviour of HOCs in a wide range of soils, and that consider exposure-specific scenarios, be investigated. Exposure-specific scenarios are important for validation purposes, which may be useful for the development of standardised methods and procedures for HOC bioaccessibility determinations. Research is needed to propose the most appropriate testing methods and for assessing potential risks posed by residual fractions of HOCs. Such investigations may be useful for minimising uncertainties associated with a risk-based approach, so that consideration may then be given to its adoption on a global scale. This review critically appraises existing information on the bioavailability of HOC residues in soil to establish whether there may be risks from highly sequestered contaminant residues.
基于风险的方法来管理污染土地，而不是基于完全去除污染物的方法，已经被接受，因为它们更可行且具有成本效益。基于风险的方法旨在将特定污染物暴露给人类的风险最小化。然而，采用基于风险的方法而不是其他过于保守的方法，需要理解并最小化决策中的相关不确定性。无论污染物的性质如何，一个关键的不确定性是，在土壤中残留的污染物是否存在与人类和其他生态受体暴露相关的潜在风险，以及在风险评估过程中应如何考虑这些风险。本综述重点关注疏水性有机污染物（HOCs），特别是多环芳烃（PAHs），表明从风险角度来看，污染物的残留部分存在很大的不确定性。这是因为很少有研究集中在理解 HOCs 的解吸行为上，几乎没有研究考虑暴露特定因素的影响。特别是，目前还不清楚土壤中结合的 HOCs 暴露于胃肠道液体和酶过程中是否会释放结合的残留物。尽管已经使用体外模型来预测 PAH 的生物可利用性，并且已经使用化学提取来确定各种土壤中的残留部分，但对于实际测量的内容仍存在疑问。因此，目前尚不确定哪种生物可利用性方法代表了体内 PAH 生物利用度的最佳选择或最佳估计。建议研究广泛的土壤中 HOC 的命运和行为，并考虑暴露特定的情况。暴露特定的情况对于验证目的很重要，这可能有助于开发 HOC 生物可利用性测定的标准化方法和程序。需要研究提出最合适的测试方法，并评估 HOC 残留部分带来的潜在风险。这些调查可能有助于最小化与基于风险的方法相关的不确定性，以便随后考虑在全球范围内采用该方法。本综述批判性地评估了土壤中 HOC 残留生物有效性的现有信息，以确定是否存在高度隔离污染物残留带来的风险。
