Regional human health risk assessment of cadmium and hexachlorocyclohexane for agricultural land in China.

Widespread pollution of agricultural soil is posing great risks to food safety and human health. The absence of human health-based Generic Assessment Criteria (GAC) for agricultural land means Chinese farmers struggle to manage these risks efficiently and effectively. Cadmium (Cd) and hexachlorocyclohexane (HCH), two of the most concerned contaminants, demonstrate threshold toxicity meaning that background exposure (MDIoral) is considered when deriving soil Generic Assessment Criteria (GAC). The CLEA (Contaminated Land Exposure Assessment) model was used to derive GAC for Cd and HCH that reflect differences in diet and soil characteristics across 19 provinces/cities. For both cadmium and alpha-HCH, Sichuan had the lowest GAC of 0.379 mg kg-1 and 0.0136 mg kg-1, respectively, resulting from its significant high MDIoral values, which are approximately six to nine times larger than the average MDIoral for all the 19 provinces/cities. Jiangxi province had the highest GAC of 1.230 mg kg-1 and 0.0866 mg kg-1, respectively, for cadmium and alpha-HCH, caused by its notable low MDIoral values and low vegetable consumption rate. Human health risk assessment based on regional GAC for Cd revealed that agricultural land with very high to high risks is located in southern China, while very low-risk land is located in northern China. For HCH, alpha- and gamma-HCH pose negligible health risks, but beta-HCH poses some health risk in some of the provinces/cities. When applying the regional GAC for beta-HCH, agricultural land in Beijing and Sichuan posed the highest risk, and those in Heilongjiang and Jiangxi had the lowest risk. This reflects the significant influence of background and vegetable consumption pathway on the GAC. Regional GACs could simplify and speed up risk assessment of agricultural land in different regions of China, by avoiding the need to calculate site-specific assessment criteria, thus saving time and money by avoiding over or under remediation.

Soil-sebum partition coefficients for high molecular weight polycyclic aromatic hydrocarbons (HMW-PAH).

In vitro high molecular weight polycyclic aromatic hydrocarbons (HMW-PAH) soil-sebum partition coefficients (KSS) were measured for twelve soils collected from former UK gasworks. Concentrations of ∑16 USEPA PAH in the soils ranged from 51 to 1440 mg/kg. Time series extractions (0.5, 1, 2, 4, 8 and 24 h) at skin temperature (32 °C) of HMW-PAH from sebum to soil for two samples were conducted to determine the maximum release time-step. The maximum HMW-PAH release time-step was determined as 4 h, which was subsequently used as the extraction time for the remaining samples. The 4 h extraction for all samples showed HMW-PAH KSS ranging from 0.06 to 1.4 (median = 0.59; mean = 0.59; standard deviation = 0.27; median absolute deviation = 0.29). Evaluation of KSS data for the 4 h extractions showed that soil type and selected HMW-PAH properties (literature based molecular weight and octanol-carbon partition coefficients) affect the amount of HMW-PAH released from soil into sebum.

Generic assessment criteria for human health risk management of agricultural land scenario in Jiangsu Province, China.

The widespread of agricultural soil pollution in China is posing great risks to food safety and human health. Lack of human health-based generic assessment criteria (GAC) for Chinese agricultural land makes it impossible to efficiently screen and assess the risks unless site-specific risk assessments being carried out, which are both time-consuming and costly. This paper has thus derived the first set human health-based generic assessment criteria (GAC) for 13 substances of concern (including isomers) using the CLEA model for agricultural land scenario in Jiangsu province of China. As there is no authoritative human health risk assessment model in China yet, this paper has determined and demonstrated the applicability of the CLEA model to Chinese agricultural land exposure scenarios. The derived GAC are generally less stringent than the current two Chinese standards (i.e. GB 15618-2018, GB36600-2018) for most substances except for five substances (including cadmium, nickel, alpha-HCH, beta-HCH and gamma-HCH) for which the oral background intake accounts for 50% of the Total Daily Intake. This indicates that the two Chinese soil quality standards maybe over conservative, and oral background intake (i.e. MDIoral) can be a critical parameter when deriving regional GAC for Chinese agricultural land scenarios. Since there is a notable regional difference in MDIoral for some of the substances of concern, as well as in the vegetable consumption rates and vegetable varieties consumed, it is considered necessary to derive GAC for other provinces of China for agricultural land scenario, to further examine the sensitivity of MDIoral on GAC. In addition, the 13 substances of concern in this paper are some of the most prevalent contaminants in agricultural soils in China, but GAC for some emerging new contaminants, such as thallium, vanadium, should also be derived in further research.

A study of "cancer villages" in Jiangsu Province of China.

China's economic boom has created many environmental and health challenges, including so-called cancer villages. This study, the first to use the lens of "cancer villages" at provincial level, examines the correlation between changes in Jiangsu cancer villages and economic and environmental quality indicators identified as being relevant, and hence to highlight environmental issues that should be mitigated to protect public health. Since 2001, 25 cancer villages have been reported in Jiangsu. The distribution pattern of these villages is of a cluster whose mean centre had moved from Suzhou city in 2001 to Taizhou in 2006 and 2011. By applying the buffer analysis tool of ArcGIS10.2.2 using 3-km and 5-km radius buffer, to examine the relationship between these cancer villages and the surrounding rivers, it was revealed that 76% of the villages fall within the 3-km buffer zone, and 88% are within the 5-km buffer zone. A fairly strong correlation between the cancer villages and annual GDP, as well as pollutant discharge, was found, with correlation coefficients of 0.94 for Jiangsu, 0.89 for Northern Jiangsu, 0.93 for Central Jiangsu, 0.83 for Southern Jiangsu and 0.64 for city level. The change of newly added cancer villages is significantly influenced by the discharge of sewage water (raising COD) and SO2, and the peak of newly added cancer villages, as well as discharge of COD and SO2 all occurred in 2005. For four cities, the total sewage water discharge and SO2 emissions are consistent with the order of the distribution density of the villages. The phenomenon of cancer villages in China will gradually be resolved as the government takes effective measures to tackle environmental issues coupled with people's increasing environmental and health awareness.

Soil and land use research in Europe: Lessons learned from INSPIRATION bottom-up strategic research agenda setting.

We introduce the INSPIRATION bottom-up approach for the development of a strategic research agenda for spatial planning, land use and soil-sediment-water-system management in Europe. Research and innovation needs were identified by more than 500 European funders, endusers, scientists, policy makers, public administrators and consultants. We report both on the concept and on the implementation of the bottom-up approach, provide a critique of the process and draw key lessons for the development of research agendas in the future. Based on identified strengths and weaknesses we identified as key opportunities and threats 1) a high ranking and attentiveness for the research topics on the political agenda, in press and media or in public awareness, 2) availability of funding for research, 3) the resources available for creating the agenda itself, 4) the role of the sponsor of the agenda development, and 5) the continuity of stakeholder engagement as bases for identification of windows of opportunity, creating ownership for the agenda and facilitating its implementation. Our derived key recommendations are 1) a clear definition of the area for which the agenda is to be developed and for the targeted user, 2) a conceptual model to structure the agenda, 3) making clear the expected roles, tasks, input formats regarding the involvement and communication with the stakeholders and project partners, 4) a sufficient number of iterations and checks of the agenda with stakeholders to insure completeness, relevance and creation of co-ownership for the agenda, and 5) from the beginning prepare the infrastructure for the network to implement the agenda.

Determination of the potential implementation impact of 2016 ministry of environmental protection generic assessment criteria for potentially contaminated sites in China.

The Ministry of Environmental Protection of China issued a 3rd draft edition of risk-based Generic Assessment Criteria (the MEP-GAC) in March 2016. Since these will be the first authoritative GAC in China, their implementation is likely to have a significant impact on China's growing contaminated land management sector. This study aims to determine the potential implementation impact of the MEP-GAC through an in-depth analysis of the management context, land use scenarios, health criteria values adopted and exposure pathways considered. The MEP-GAC have been proposed for two broad categories of land use scenarios for contaminated land risk assessment, and these two categories of land use scenarios need to be further delved, and a MEP-GAC for Chinese cultivated land scenario ought to be developed, to ensure human health protection of Chinese farmers. The MEP-GAC have adopted 10-6 as the acceptable lifetime cancer risk, given the widespread extent and severe level of land contamination in China, consideration should be given to the decision on excess lifetime cancer risk of 10-5. During risk assessment process in practice, it is better to review the 20% TDI against local circumstances to determine their suitability before adopting it. The MEP-GAC are based on a SOM value of 1%, for regions with particularly high SOM, it might be necessary to develop regional GAC, due to SOM's significant impact on the GAC developed. An authoritative risk assessment model developed based on HJ25.3-2014 would help facilitate the DQRA process in practice. The MEP-GAC could better reflect the likely exposures of China's citizens due to vapour inhalation by using characteristics of Chinese exposure scenarios, including China-generic building stock, as inputs into the Johnson and Ettinger model as opposed to adoption of the US EPA parameters. The MEP-GAC once implemented will set the trajectory for the development of the investigation, assessment and remediation of land contamination for years.

Effects of drying and comminution type on the quantification of Polycyclic Aromatic Hydrocarbons (PAH) in a homogenised gasworks soil and the implications for human health risk assessment.

This research investigates the effect of nine physical treatment types comprising a serial combination of three drying (air, freeze and oven) and two comminution (milling and sieving) methods on the quantification of PAH in a soil sample from a former gasworks. Results show that treatment type has a significant effect on PAH concentration (p⩽0.05). Naphthalene, 1-methylnaphthalene and 2-methylnaphthalene concentrations were significantly higher for air drying and freeze drying treatments than for oven drying. It is suggested that naphthalene and similarly volatile PAH losses were greater for oven drying due to the application of fanned warm air which is thought to cause volatilisation. Analytical precision was significantly improved for milled samples compared with sieved samples. The reason milling results in greater precision is assigned to the improved solvent extraction efficiency when natural grain size is altered due to crushing. The analytical data were compared to residential generic assessment criteria (GAC) used for risk-based land management. It was shown that the naphthalene GAC was lower than all freeze drying and air drying concentrations but was within the oven drying concentration range, illustrating that a false negative could be concluded during risk evaluation is oven dried data were used. Overall, it is recommended that air drying or freeze drying is a better choice than oven drying if the quantification of low molecular weight PAH forms an important objective of sample characterisation for risk-based land management, otherwise freeze drying and milling is recommended.

Mine spoil acts as a sink of carbon dioxide in Indian dry tropical environment.

Economically important mining operations have adverse environmental impacts: top soil, subsoil and overburden are relocated; resulting mine spoils constitute an unaesthetic landscape and biologically sterile or compromised habitat, and act as source of pollutants with respect to air dust, heavy metal contamination to soil and water bodies. Where such spoils are revegetated, however, they can act as a significant sink for atmospheric carbon dioxide (CO2) through combined plant succession and soil formation. Revegetation, drainage, reprofiling and proper long term management practices help recapture carbon, improve soil quality and restore the soil organic matter content. A survey along an age gradient of revegetated mine spoils of 19 years in Singrauli, India by the authors showed an accumulation of total C in total plant biomass, mine soil and soil microbial biomass by 44.5, 22.9 and 1.8 t/ha, respectively. There was an increase in total sequestered C by 712% in revegetated mine spoils after 19 years, which can be translated into annual C sequestration potential of 3.64 t Cha(-1) yr(-1). Carbon sequestered in revegetated mine spoil is equivalent to 253.96 tonnes/ha capture of atmospheric carbon dioxide (CO2). This indicates that mine spoil can act as a significant sink for atmospheric CO2. Annual C budget indicated 8.40 t Cha(-1) yr(-1) accumulation in which 2.14 t/ha was allocated to above ground biomass, 0.31 t/ha in belowground biomass, 2.88 t/ha in litter mass and 1.35 t/ha in mine soil. This shows that litter mass allocation is much important in the revegetated site. Decomposition of root and litter mass contributes C storage in the mine soil. Therefore, revegetation of mine soils is an important management option for mitigation of the negative impacts of mining and enhancing carbon sequestration in mine spoils.

Methodology for the determination of normal background concentrations of contaminants in English soil.

The revised Environmental Protection Act Part 2A contaminated land Statutory Guidance (England and Wales) makes reference to 'normal' levels of contaminants in soil. The British Geological Survey has been commissioned by the United Kingdom Department for Environment, Food and Rural Affairs (Defra) to estimate contaminant levels in soil and to define what is meant by 'normal' for English soil. The Guidance states that 'normal' levels of contaminants are typical and widespread and arise from a combination of both natural and diffuse pollution contributions. Available systematically collected soil data sets for England are explored for inorganic contaminants (As, Cd, Cu, Hg, Ni and Pb) and benzo[a]pyrene (BaP). Spatial variability of contaminants is studied in the context of the underlying parent material, metalliferous mineralisation and associated mining activities, and the built (urban) environment, the latter being indicative of human activities such as industry and transportation. The most significant areas of elevated contaminant concentrations are identified as contaminant domains. Therefore, rather than estimating a single national contaminant range of concentrations, we assign an upper threshold value to contaminant domains. Our representation of this threshold is a Normal Background Concentration (NBC) defined as the upper 95% confidence limit of the 95th percentile for the soil results associated with a particular domain. Concentrations of a contaminant are considered to be typical and widespread for the identified contaminant domain up to (and including) the calculated NBC. A robust statistical methodology for determining NBCs is presented using inspection of data distribution plots and skewness testing, followed by an appropriate data transformation in order to reduce the effects of point source contamination.

Derivation of a site-specific assessment criterion for benzo[a]pyrene in red shale at a former coking works.

A former coking works in England is being remediated to enable its redevelopment. We have developed site specific human health risk assessment criteria (SSAC) for benzo[a]pyrene (BaP) based on detailed characterisation of red shale proposed for reuse in an area allocated for residential development. Samples of red shale were analysed using the Colon-enhanced Physiologically Based Extraction Test (CEPBET) to estimate the bioaccessibility of BaP. The results indicate that between 5% and 28% of the red shale BaP is bioaccessible. A cautious value of 50% was used in calculating an SSAC. The CLEA human health assessment model was used to calculate the SSAC and any changes to the default input parameters have been discussed and justified. Based on the fact that BaP appears to be a point-of-contact, rather than a systemic, carcinogen in animal studies, individual assessment criteria were estimated for the oral, inhalation and dermal routes of entry in-line with current UK guidance. An overall SSAC of 2.5 mg/kg for BaP in red shale for the residential with home-grown produce land use was then derived as the lowest of the three route-specific assessment criteria. This value is specific to both the site and the material being assessed. The approach adopted however can be applied on other sites and for other materials to inform detailed quantitative risk assessments.

Comparison of batch mode and dynamic physiologically based bioaccessibility tests for PAHs in soil samples.

A fed state in vitro methodology capable of use in commercial testing laboratories has been developed for measuring the human ingestion bioaccessibility of polyaromatic hydrocarbons (PAHs) in soil (Fed ORganic Estimation human Simulation Test- FOREhST). The protocol for measuring PAHs in the simulated gastro-intestinal fluids used methanolic KOH saponification followed by a combination of polymeric sorbent solid phase extraction and silica sorbent cartridges for sample cleanup and preconcentration. The analysis was carried out using high pressure liquid chromatography with fluorescence detection. The repeatability of the method, assessed by the measurement of the bioaccessibility of 6 PAHs (benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[ah]anthracene, and indeno[1,2,3-c,d]pyrene) in eleven gas works soils, was approximately 10% RSD. The method compared well with the results from an independent dynamic human simulation reactor comprising of the stomach, duodenal and colon compartments tested on the same soils. The measured bioaccessible fraction of the soils varied from 10-60% for soils containing 10-300 mg kg(-1) PAH (the sum of the six studied) with total organic carbon concentrations in the soils ranging from 1-13%. A multiple regression model showed that the PAH bioaccessible fraction could be explained using the PAH compound, the soil type and the total PAH to soil organic carbon content. The method described here has potential for site specific detailed quantitative risk assessment either to modify the risk estimation or to contribute to the risk evaluation.

A critical evaluation of the implications for risk based land management of the environmental chemistry of Sulphur Mustard.

Sulphur Mustard, or "Mustard Gas" is in fact an oily liquid which was used as a chemical weapon primarily for its vesicant action which necessitates whole body protection. It is also now recognised as a carcinogenic agent upon chronic exposure. Soil contaminated with Sulphur Mustard continues to present both acute and chronic human health risks and risks to groundwater, surface water and the wider ecology at a number of sites globally and, in some cases, has done for many decades. This is at odds with the simple aqueous chemistry of the compound which would suggest that it should be short lived in the environment, especially in the presence of water. A number of studies have examined the possible factors for this longevity and, though the causes are generally assumed to be understood, the precise reasons have not yet been definitively determined and the evidence in support of the existing theories is at best circumstantial. At present, the prevailing view is that Sulphur Mustard is somehow protected by oligomeric or polymeric sulphonium species produced during incomplete hydrolysis reactions. The following review discusses the pertinent degradation mechanisms in the environment; hydrolysis and thermal degradation and the reasons put forward for the longevity of Sulphur Mustard in the literature. Other factors, such as the role of polymeric species in Sulphur Mustard droplets in modifying the mobility of the agent are also examined. Ultimately, without a thorough understanding of the abiotic fate of the Sulphur Mustard, uncertainties will remain in the application of risk assessment and remediation strategies to such sites, potentially compromising the validity or effectiveness of such actions.

Incorporating bioaccessibility in detailed quantitative human health risk assessments.

Current English policy and practice allows, and in places encourages, site specific estimates of arsenic oral bioavailability to be used in detailed quantitative human health risk assessment. English land contamination legislation does not differentiate between natural and man made arsenic soil contamination. English planning guidance requires developers to demonstrate that new houses are fit for purpose, including ensuring that there are no unacceptable risks to human health from soil contaminants. Naturally occurring arsenic in soils at a new housing site in southwest England was demonstrated not to pose unacceptable risk to human health by site specific estimates of bioavailability and region specific estimates of soil to plant uptake factors. Independent lines of evidence were used to justify the arsenic exposure factors for oral bioavailability and soil to plant uptake. Using site specific assessment criteria based on tools and information that give a better estimate of the actual exposure avoided both unnecessary public concern and considerable local authority expenditure across the outcrop of such soils as part of their legal duties.