基于健康风险的土壤修复目标值的研究——以某多环芳烃污染场地为例

以某多环芳烃污染场地为研究对象,根据场地未来使用功能和场地实际情况,对该场地进行了健康风险评价.根据国家环保部新出台的《污染场地土壤修复技术导则》（HJ25.3-2014）,确定了健康风险评价模型中相关参数;计算得出了该场地的修复目标值苯并（a）芘为0.012 mg/kg;茚并（1,2,3-cd）芘为0.12 mg／kg.     

Presence and distribution of PAHs,PCBs and DDE in feed and sediments under salmon aquaculture cages in the Bay of Fundy,New Brunswick,Canada

• 1. Wastes from feed and faeces can result in the deposition of contaminants in sediments around aquaculture sites. Five types of feed pellet, a commercial fish oil and 76 sediment samples collected under and up to 100 m away from salmon aquaculture cages in the south‐western Bay of Fundy between 1998 and 2000 were analysed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides.
• 2. Five alkylated naphthalenes (aNAs) were consistently detected in fish oil (116–180 ng g^?1, per aNA), in pellets (25–51 ng g^?1, dry weight, per aNA), and sediments (<1–45 ng g^?1, dry weight, per aNA). Other PAHs were detected at variable levels in feed or in sediments.
• 3. IUPAC congener 153 (a PCB) and p,p′‐dichlorodiphenyldichloroethylene (p,p′‐DDE) were detected more frequently than other chlorinated targets in oil (108 ng g^?1 and 176 ng g^?1 respectively), feed (<1–14 ng g^?1 and 1.7–28.2 ng g^?1 respectively) and sediments (<0.08–3 ng g^?1 and <0.5–7 ng g^?1 respectively).
• 4. Trends were observed during the first year of sediment sampling (1998), with higher organic carbon, PCBs and p,p′‐DDE levels below the cages than 50 m away. The PAHs other than aNA showed an opposite trend with distance. In 1999, levels of p,p′‐DDE and PCBs were somewhat reduced under the cages, but were detected up to 100 m away from the cages.
• 5. Levels of aNA tended to be higher at some sites in 1999 relative to 1998, reflecting variability in feed and/or differential transport or degradation of contaminants relative to the environmental background. When detected, mean levels of PCBs and DDE were 2–10 times lower in 2000 than in 1999, and PAHs were 30–40% lower in 2000 than in 1999.
• 6. Interpretation of the results is done cautiously, since the exact locations of the sites sampled is only known to an intermediate facilitating the work between farmers and scientists. Levels of contaminants are compared with international results, interpreted relative to potential toxicity, uptake from feed, from deposited sediments, and in the framework of an aquaculture decision‐support system published recently.

Copyright © 2005 John Wiley & Sons, Ltd.     

深圳市不同城市密度区中环芳烃的发生、来源及生态风险评估

Urbanization may cause increased exposure levels to polycyclic aromatic hydrocarbons(PAHs) and associated health risks for over half of the world's population living in cities,but little evidence has shown a direct spatial relationship between urbanization and soil PAH pollution.Based on the monitored PAH concentrations in 188 topsoil(0-5 cm) samples in Shenzhen,the most rapidly developing city in China,in recent decades,we applied geographical demarcation to determine the occurrences,source apportionments,and spatial ecological risks of soil PAHs across five zones of varying urban densities.Mean concentrations of the 16 US Environmental Protection Agency(EPA) priority PAHs(Σ_(16)PAHs) and the 7 carcinogenic PAHs(Σ_7CarPAHs) both followed the order:Zone D(60%-80%constructive land density(CLD)) Zone E(80%-100%CLD) Zone C(40%-60%CLD) Zone B(20%-40%CLD) Zone A(0%-20%CLD),suggesting that the highest PAH levels occurred in the suburban-urban center transitional zone(Zone D) rather than the urban center zone(Zone E) in Shenzhen.There were significant correlations of Σ_(16)PAHs to TOC and sampling altitude across all samples but not within highly-urbanized regions(Zones D and E),implying a considerable disturbance of urbanization to the soil PAH pool.Source apportionments suggested that soil PAHs of all zones were mainly derived from fossil fuel combustion,with Zone E showing the highest contribution from oil sources among different zones.Spatial ecological risk analysis showed that the contaminated area(467 km~2;23.9%of total area;toxic equivalency quotients 33 ng g~(-1)) had a higher contribution from the highly-urbanized regions(Zones D and E) than the uncontaminated area(42.3%vs.18.1%).Overall,our study highlighted a strong spatial relationship between urbanization and soil PAH pollution.     

PAK-Abnahmen in Bodenproben verschiedener Altlaststandorte bei Aktivierung der autochthonen Mikroflora

PAH decrease in soil samples from different polluted industrial sites by activating the autochthonous microflora In pot experiments under field conditions the PAH decrease in ten different soil samples from former industrial sites with differing PAH load were investigated over a period of 74 and 168 weeks. 15 out of 16 PAH according to US EPA (without acenaphthylene) were determined. Easily degradable organic matter, mineral fertilizers, synthetic surfactants and in some experiments also lime were added to the soil samples in varying amounts. Depending on the nature and quantity of the amendments, the biological activity and (co-)metabolic decomposition of PAH by soil microorganisms could considerably be increased. In the different soil samples a decrease of the initial PAH contents between 12 and 90% was achieved within 74 weeks. Even from 74 up to 168 weeks for some soil samples a remarkable further decrease of the PAH contents could be observed. The decrease of the extractable PAH with time is mainly caused by microbial decomposition and formation of nonextractable residues. This behavior can be fitted by two coupled exponential functions, one for an initial phase of rapid decomposition and the other for a subsequent phase of slow decomposition. Therefore, two different processes (I, II) determine the decrease of PAH. In the first week of the experiment the decomposition rates for process I amount to 4.2–88.3 and for process II to 0.06–5.3 mg PAH ? kg^?1 soil ? week^?1; in the 168th week they are no longer determinable for process I and amount to 0.05–2.3 mg ? kg^?1 ? week' for process II. Higher initial PAH contents often led to higher relative PAH decreases, but also to absolute higher contents of residues. The persistence of PAH is mainly determined by their bioavailability. PAH degradation is increased by the soil treatments. The addition of easily degradable organic matter (C/N ratio < 20) in a quantity of 30g ? kg^?1 (w/w) combined with the addition of nitrate and a surfactant most effectively increased the degradation of PAH. Raising the pH of a very strongly acidic soil sample revealed a maximum PAH decomposition at a pH of 6.     

亚热带地区农业土壤和植物中多环芳烃的分布

以汕头经济特区的农业土壤和蔬菜为例,运用气相色谱-质谱方法对美国EPA优控多环芳烃(PAH)进行定性、定量测定,分析了其在中国亚热带地区农业土壤和植物中的分布特征,讨论了影响其分布的主要因素.结果表明:该区农业土壤中的PAH以3环和4环为主,单个PAH以萘、菲、荧蒽和苯并[b]萤蒽为主;而植物中的PAH以3环为主,单个PAH以萘、菲为主.PAH可在0～100 cm的土层范围内有效移动和传输,其中表层土壤的输入比率要高于移动和传输的比率.影响PAH在土壤和植物中分布的因素除PAH本身的理化性质外,土壤的理化性质、植物种类和环境条件同时起重要的作用.     

A Chronic Plant Test for the Assessment of Contaminated Soils. Part 1: Method development (9 pp)

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PREAMBLE According to the German Federal Soil Protection Act (BBodSchG 1998), the habitat function of soils must be protected. Despite the fact that in the Federal Soil Protection Ordinance (BBodSchV 1999) it has not been established how this goal can be reached reliably, it is clear that such a biological function can only adequately be assessed using biological test methods. This is especially true when a soil is contaminated by a mixture of often unknown chemicals. In such a case the use of chemical analysis aiming at a small range of known substances is not sufficient and must therefore be supplemented by biological methods. For this reason, several standardised test methods are available (e.g. using earthworms, collembolans or plants; Römbke and Knacker 2003; ISO 2003). Since acute tests are usually not sensitive enough for the assessment of potentially contaminated soils (e.g. Hund-Rinke et al. 2002), chronic tests like the earthworm reproduction tests (ISO 1998) are recommended for this purpose.

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A chronic plant test for the determination of phytotoxicity was missing until quite recently. The term phytotoxicity is understood here as the capacity of a compound or a contaminated soil to cause temporary or long-lasting damage to plants (EPPO 1997). Therefore, the German Ministry for Education and Research sponsored a project (1997 – 1999) in which – based on existing standardised methods – such a chronic plant laboratory test was developed and partly validated (Kalsch and Römbke 2000). The new test can be used for the evaluation of single chemicals (see Part 1 of this mini-series) as well as for the assessment of contaminated or remediated soils (see Part 2 of this mini-series).

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ABSTRACT Background and Scope. As part of the efforts to improve the biological testing of contaminated soils, the German government sponsored the standardisation of a chronic plant bioassay. This new test is based on experiences with various acute plant tests (e.g. published by OECD or ISO) and existing North American Plant-Life-Cycle Bioassays. In this contribution the characteristic properties of the test are described.

Methods

The test can be performed either with Brassica rapa (turnip) or Avena sativa (oat). Its duration is 35 to 64 days with OECD artificial soil and a German standard field soil acting as controls. Water and nutrients are provided by an automatic wick irrigation system. Besides measuring biomass and shoot length, the number of pods, seeds and flowers are applied as chronic measurement endpoints. During the development of the test, TNT (2,4,6-trinitrotoluene) and Pyrene were used as model test substances.

Results

Pyrene did not affect B. rapa (turnip) in concentrations of up to 10.000 mg/kg soil (due to the often low sensitivity of A. sativa (oat) no further test with this substance was performed). Depending on the endpoint the results varied in the tests with TNT. With few exceptions, the NOEC (No Observed Effect Concentration) values were determined as 55.5 mg TNT/kg soil for B. rapa (turnip) and as 75 (unfertilised) and 150 (fertilised) mg TNT/kg soil for A. sativa (oat). The EC50-values varied between 96.3 and 207.2 mg TNT/kg soil for B. rapa (turnip) and 183.1 – 505.6 mg TNT/kg soil for A. sativa (oat), depending on the endpoint.

Outlook

The results of this work have been used to prepare a draft test guideline, which has recently been standardised by the International Organisation for Standardisation (ISO). Practical experiences with this test system are described in Part II of this mini series.     

湛江市区不同利用类型土壤的PAHs污染特征和来源

首次对湛江市表层土壤PAHs污染进行研究,并根据利用类型对其进行分类讨论。虽然湛江市的环境质量在全国名列前茅,但研究显示随着重化工业的快速发展,湛江市土壤已受到一定程度的PAHs污染,∑PAHs的平均含量达491.1ng.g-1,低于珠三角的发达城市,而高于中等城市,特别是某些工业区污染严重,超过荷兰相关标准;与其它城市一样,湛江市土壤PAHs的组分构成以4环和5环为主,占∑PAHs的65.1%。∑PAHs的变化趋势为旧厂址>市区工业区>交通>郊区工业区>休闲>农业,市区>郊区;3环组分比重随市中心距离的增大而增加,4环和5环则相反,6环差异较小。农业和郊区工业高比重的3环组分可能与市区石油源PAHs的大气输送有关。已搬迁工厂高含量∑PAHs表明PAHs在土壤的积累影响是长期的,而休闲区178.7 ng.g-1的∑PAHs则表明解决PAHs的污染问题必须解决污染源问题。利用4种PAHs比值判断湛江市土壤PAHs的来源主要是石油源、石化燃烧和煤、柴等生物燃烧源的混合源,与湛江市社会经济情况相符。     

上海市土壤中持久性毒害污染物和盐分含量特征研究

Some farmland soils in Shanghai had high salinity levels, suggesting secondary salinization of the soils. The soil problems in Shanghai were studied, including the salinity and nitrate nitrogen (NO₃^--N) concentrations, heavy metal pollution characteristics, and organochlorine pesticide (OCP) residual levels and polycyclic aromatic hydrocarbon (PAH) contents. Accumulation of NO₃^--N in vegetable soils was the most significant among different functional soils. Heavy metal pollution was significant in the samples collected from the sewage-irrigated land and roadside. The identification of the metal sources through multivariate statistical analysis indicated that Pb, Zn, Cu and Cr in urban soils were from the traffic pollutants; excessive application of fertilizer and irrigation were the main reasons for the metal pollution in agricultural soils; Ni in the observed soils was controlled by parent soils. OCPs could still be detected in farmland soils but degraded greatly in last 20 years after prohibition of their usage. PAHs with 2-3 rings were the main components in industrial soils. The concentrated PAHs in the investigated soils were likely from petroleum and coal combustion.     

Soil microbial response during the phytoremediation of a PAH contaminated soil

The aim of this trial was to quantify and compare the responses of soil microbial communities during the phytoremediation of polycyclic aromatic hydrocarbons (PAHs) in a laboratory trial. The experiment was conducted in 1-kg pots and planted treatments consisted of a mixed ryegrass (Lolium perenne) and white clover (Trifolium repens) sward together with a rhizobial inoculum (Rhizobium leguminosarum bv. trifolii). Throughout the 180-d experiment soil microbial biomass and communities of PAH degraders were monitored. PAH degradation was enhanced in planted treatments that received a rhizobial inoculum. Microbial biomass was enhanced in planted treatments, but there were no significant differences between treatments that had received a rhizobial inoculum and those that had not. However, numbers of PAH degraders were greater in the treatment that had received a rhizobial inoculum.     

Bioaugmentation and biostimulation effects on PAH dissipation and soil ecotoxicity under controlled conditions

The degradation of spiked anthracene (ANT), pyrene (PYR) and benzo[a]pyrene (B[a]P) in soil (3000 mg ∑ 3 PAHs kg⁻¹ dry soil) was studied in aerobically incubated microcosms for 120 d. The applied treatments aimed at enhancing PAH removal from the heavily contaminated soils are: (i) bioaugmentation by adding aged PAH-contaminated soil (ACS) containing activated indigenous degraders; and (ii) combined bioaugmentation/biostimulation by incorporating sewage sludge compost (SSC) and decaying rice straw (DRS). The adopted treatments produced higher PAH dissipation rates than those observed in unamended PAH-spiked soils, especially for ANT and PYR in the presence of DRS or ACS (>96%). However, B[a]P was the most recalcitrant hydrocarbon to biodegradation. Extracellular enzyme investigation revealed the existence of ligninolytic activities in all soil treatments, including control but no relationship could be found with PAH dissipation. The ecotoxicological assessment indicated that regardless of applied treatment, PAH-spiked soils were chronically lethal to ostracod Heterocypris incongruens and confirmed the sensitivity of the microcrustacean to the concomitant presence of these three hydrocarbons. Lettuce root elongation inhibition was correlated with PAH level but the presence of SSC conferred a strong phytotoxic capacity to PAH-spiked soils. DRS amendment may constitute a cost-effective alternative for hydrocarbon bioremediation as it has impacted positively on soil microbial activity and enhanced PAH removal with no apparent changes in soil physico-chemical properties.