Health risk assessment of organic pollutants in Jiangsu reach of the Huaihe River, China

Unregulated discharge of wastewater in the Mahanadi River Basin: Risk evaluation due to occurrence of polycyclic aromatic hydrocarbon in surface water and sediments

Exposure to polycyclic aromatic hydrocarbons (PAHs) through contaminated water may adversely affect human health and ecology. Water and sediment samples collected from the Mahanadi River Basin (MRB) were analyzed for the presence of sixteen priority PAHs. Results showed that the concentrations of Σ16 PAHs in water and sediments ranged from 13.1 to 685.4 μg/L and 302.6 to 728.2 ng/g. In river water samples, the highest mean concentrations were recorded for Acenaphthylene (18.73 ± 11.61 μg/L) and Benzo(a)Anthracene (10.11 ± 8 μg/L). On the contrary, the maximum concentration was recorded for Phenanthrene (96.18 ± 50.66 ng/g) and Pyrene (76.69 ± 22.73 ng/g) in sediment samples. Human health risk assessment suggests low risk, with incremental lifetime cancer risk (ILCR) being 37.44 × 10^-5 for children and 21.82 × 10^-5 for adults. In contrast, ecological risk assessment showed a high toxic equivalent quotient of 40.68 ng/g and mutagenic equivalent quotient of 39.74 ng/g suggesting elevated adverse risk to aquatic species.

Double-endpoint Genotoxicity Quantification and PAHs Characterization of Drinking Water Source alongside Polluted Yinghe River with High Tumor Mortality

The etiology for the high tumor mortality in heavy polluted Yinghe river basin is still unclear and polycyclic aromatic hydrocarbons (PAHs) belong to the priority pollutants in water based on the former surveillance data. In order to explore the potential genotoxicants contributing to the double-endpoint genotoxicity of polluted drinking water source, 12 groundwater and 3 surface water samples were collected from 3 villages and the nearby rivers alongside Yinghe river basin, respectively and their comprehensive genotoxicity was estimated with a bioassay group of SOS/umu test and micronucleus (MN) test (MNT). Some groundwater samples showed positive genotoxicity and all surface water samples were highly genotoxic. Eight groundwater samples showed DNA genotoxic effect with the average 4-NQO equivalent concentration (TEQ_(4-NQO)) of 0.067 µg/L and 0.089 µg/L in wet and dry season, respectively. The average MN ratios of groundwater samples were 14.19‰ and 17.52‰ in wet and dry season, respectively. Groundwater samples showed different genotoxic effect among 3 villages. The total PAHs concentrations in all water samples ranged from 8.98 to 25.17 ng/L with an average of 14.97±4.85 ng/L. BaA, CHR, BkF, BaP and DBA were the main carcinogenic PAHs contributing to the genotoxicity of water samples. In conclusion, carcinogenic PAHs are possibly related to the high tumor mortality in the target area. Characterization of carcinogenic PAHs to genotoxicity of drinking water source may shed light on the etiology study for high tumor mortality in Yinghe river basin.

Environmental status of an Italian site highly polluted by illegal dumping of industrial wastes: The situation 15 years after the judicial intervention

In 2008 the Italian government classified the Bussi sul Tirino area (Central Italy) as Site of National Interest destined to remediation which, unfortunately, has not yet begun. The decision followed >20 years of illegal dumping of industrial wastes, lasting from 1984 to 2005, that generated the biggest illegal toxic waste disposal site in Europe. The contamination profile of the site was mainly characterized by PCDD/Fs, PCBs, PAHs, chlorinated solvents, Hg, and Pb. Due to the health concern of the population and local authorities, an extensive monitoring and biomonitoring campaign was carried out in 2017-2018, checking the site-specific pollutants in local food (free-range hens' eggs, milk from grazing sheep and goats, wild edible mushrooms, and drinking water), environmental (air and freshwaters) and biological (human urine) matrices. A total of 314 samples were processed, obtaining 3217 analytical data that were compared with regulatory limits, when available, and values reported by international literature. The sum PCDD/Fs and DL-PCBs ranged from 0.24 to 3.6 pg TEQ g^-1 fat, and from 0.46 to 8.3 pg TEQ g^-1 fat, respectively in milk in eggs, in line with the maximum levels established by CE Regulations except for an egg sample. As regards PAHs, all our results were lower than the literature data, as well as for Hg and Pb. Outdoor air showed levels of chlorinated solvents ranging from <LOD to 36 μg m^-3, and freshwaters from 0.21 to 2.8 μg L^-1. All drinking water samples resulted compliant with the maximum levels established by the current EU directive. Despite the severe pollution of the illegal dumping site and the remediation not yet carried out, the local environment and the population living in Bussi and surroundings seem not to be affected by significant exposure to the toxics characterizing the landfill.

Health Risk Assessment, Composition, and Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Drinking Water of Southern Jharkhand, East India

The studies on polycyclic aromatic hydrocarbons (PAHs) occurrence, distribution, health risk, and composition in drinking water are limited in India and worldwide. The main objective of this study was to find the contaminant sources, composition, health risk, and distribution of USEPA's 16 priority pollutant PAHs in the drinking water samples collected between July 2019 to September 2019 from six districts of Southern Jharkhand. The Σ_16PAHs mean ± standard deviation [SD] concentration values were ordered as East Singhbhum (ES) (21.5 ± 14.8 ng L^-1) > West Singhbhum (WS) (16.57 ± 13.21 ng L^-1) > Saraikela Kharsawan (SK) (11.48 ± 9.92 ng L^-1) > Khunti (KH) (10.32 ± 9.09 ng L^-1) > Simdega (SM) (9.96 ± 7.85 ng L^-1) > Gumla (GU) (9.41 ± 8.63 ng L^-1). The results show that ES and WS districts' groundwater samples were more contaminated by the PAHs, which may be attributed to the presence of many small-, medium-, and large-scale industries and high vehicular density in these districts. The concentrations of lower molecular weight ring (3-rings) and middle molecular weight ring (4-rings) PAHs were dominant throughout all drinking samples. The concentration of the 3-ring PAH Anthracene and 4-ring PAH Fluoranthene were dominant in all districts. The molecular ratios suggested that the potential sources of PAHs are fuel combustion and coal, grass, and wood burning. Risk assessment shows that the incremental lifetime cancer risk and risk index (RI) were ranged from 0.02 × 10^-10 to 4.93 × 10^-10 for children and 0.01 × 10^-10 to 2.98 × 10^-10 for adults. The RI values for seven carcinogenic PAHs were 8.83 × 10^-10 for children and 7.38 × 10^-10 for adults. Although the carcinogenic risks were within the permissible values, chronic exposure to PAHs through the ingestion of drinking water could still be a human health concern.

Characteristics and Health Risk Assessment of Semi-Volatile Organic Contaminants in Rural Pond Water of Hebei Province

Pond water as surface water has certain environmental impacts on environmental media such as groundwater, lakes, atmosphere, and soil. Organic pollutants present in pond water may pose health risks to humans, but research on organic pollutants in pond water is rare. Here, taking pond water collected in rural areas of Hebei province as the sample, we analyzed and evaluated four categories of semi-volatile organic compounds (SVOCs), including 11 phenolic compounds, 7 aniline compounds, 16 parent polycyclic aromatic hydrocarbons (PAHs), 14 PAH derivatives, and 16 phthalate esters (PAEs). The results show that the 10 water samples contained 26.2–17034 ng/L of Σ phenols, 33.7–2612 ng/L of Σ anilines, 33.9–1651 ng/L of Σ PAHs, and 59.0–2800 ng/L of Σ PAEs. Furthermore, non-carcinogenic risk and carcinogenic risk caused by SVOCs through direct ingestion and dermal exposure were also assessed. The current levels of non-carcinogenic risks and carcinogenic risks through these two means of exposure are within acceptable limits, except for the site 1 and site 5 in Hebei province where a total cancer risk exceeds 10⁻⁶. It can be concluded that the pond water studied had a low risk of carcinogenicity to the human.

Performance of a novel magnetic solid-phase-extraction microsphere and its application in the detection of organic micropollutants in the Huai River, China

Solid phase extraction has been increasingly applied for the detection of organic micropollutants (OMPs). However, time-consuming and high-cost disadvantages also limit the widespread use of this method, especially for the extraction of large-volume field water samples. In this study, a gas chromatography-mass spectrometry (GC-MS) method based on the magnetic microsphere (M150) solid-phase-extraction (MSPE) was established to investigate the OMPs in source water throughout the whole Huai River. In brief, the results demonstrated that the extraction efficiency of the M150 was superior to that of C₁₈ and HLB for the selected OMPs, including species of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), phthalate esters (PAEs) and nitrobenzenes (NBs), and the method detection limits of M150 for these OMPs were comparable to those of C₁₈ and HLB. The optimized conditions of extraction and elution were the 100 mg/L dosages of microspheres, extraction time of 60 min and pH of 2, and the eluent with a similar polarity, hydrophobicity and molecular structure to the OMPs rendered higher elution efficiencies. A total of 21 types of OMPs affiliating to PAHs, OCPs, PAEs and NBs were detected by the established method, with the total concentrations of 505-2310 ng/L in source water of the Huai River. Spatial differences of the OMPs were also observed, demonstrating the link between pollutant profiles and geographical locations. This study provides an alternative to enrich OMPs in filed water samples, and it reveals pollutant profiles of source water throughout the whole Huai River.

Distribution pattern and health risk assessment of polycyclic aromatic hydrocarbons in the water and sediment of Algoa Bay, South Africa

Polycyclic aromatic hydrocarbons are amongst the pollutants of major concern in the terrestrial and aquatic habitats. They are mostly characterised by carcinogenic and non-carcinogenic effects. Distribution and potential health risks of sixteen priority PAHs in the water and sediment samples collected between December 2015 and June 2016 from Algoa Bay, South Africa, were evaluated. Water and sediment samples collected were extracted with liquid-liquid and soxhlet extraction methods, respectively, and then cleaned up using glass column loaded with silica gel. Final concentrations of the target PAHs were determined by gas chromatography interfaced with flame ionization detector. Results indicated that individual PAH concentrations in surface water, bottom water and sediment samples ranged from not detected (ND) to 24.66 µg/L, ND to 22.81 µg/L and ND to 5.23 mg/kg correspondingly. Total PAHs concentrations varied as 12.78-78.94 µg/L, 1.20-90.51 µg/L and 1.17-10.47 mg/kg in the three environmental matrices in that order. The non-carcinogenic risk was generally below 1, whereas risk indices (dermal contact) were above the acceptable limit of 1 × 10^-4 in the water column, suggesting possible carcinogenic effects to humans, with adults being the most vulnerable. Similarly, highest contributions to TEQs and MEQs in the sediments were made by benzo(a)pyrene and dibenzo(a,h)anthracene, the two most toxic congeners, signifying the possibility of carcinogenicity and mutagenicity in humans. Diagnostic ratios of PAHs reflect a prevailing pyrogenic input all through. The pollution was albeit moderate, yet regular check is recommended to ensure safe and healthy environment for human and aquatic lives.

Levels of Polycyclic Aromatic Hydrocarbons in the Water and Sediment of Buffalo River Estuary, South Africa and Their Health Risk Assessment

The incidence and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in the Buffalo River Estuary in the Eastern Cape Province of South Africa were assessed in this study. A total of 60 surface water and 19 sediment samples were collected from 5 sites of the estuary over a period of 6 months (December 2015 to May 2016). Extraction of PAHs from the water and sediment samples was achieved by using liquid-liquid and soxhlet extraction methods respectively, followed by column clean up with silica gel and quantification by gas chromatography-flame ionization detection. Individual PAH levels in the water and sediment samples ranged from not detected (ND) to 24.91 μg/L and ND to 7792 μg/kg, respectively. Total concentrations of the PAHs in the water and sediment samples varied as 14.91-206 μg/L and 1107-22,310 μg/kg in that order. Total levels of the contaminants were above the target values in the two matrices and were higher in summer than autumn. Although the noncarcinogenic risk of PAHs estimated in the water column through dermal absorption was very low compared with the target value, the carcinogenic risk determined was high for both adults and children. Similarly, benzo(a)pyrene and dibenzo(a,h)anthracene were found to be of higher carcinogenic and mutagenic risks in the sediments collected from the study area. Diagnostic ratios suggest that the target hydrocarbons are predominantly from pyrolytic sources. It therefore could be inferred that the water body is conspicuously polluted; hence, efforts should be made to control all the activities contributing to such magnitude of pollution at the sites.

Bioaugmented soil aquifer treatment for P-nitrophenol removal in wastewater unique for cold regions

P-nitrophenol (PNP) is a toxic and recalcitrant organic pollutant and a usual intermediate in the production of fine chemicals, which has posed a significant threat to subsurface environment safety. Soil aquifer treatment (SAT) is a promising method to remove and remediate contamination in vadose zone with low cost and high efficiency. However, there are still research gaps for the treatment of recalcitrant contaminants by SAT in cold regions, such as un-robust indigenous microbes and low temperature constraint in vadose zone. The bioaugmentation technology was first introduced into SAT in order to enhance the removal ability of PNP by SAT operated in cold regions in this study. A high-efficiency PNP-degrading bacterium was successfully isolated, which can efficiently degrade PNP below 200 mg L^-1 with a degradation rate above 99% at 15 °C close to the real subsurface temperature in cold regions, and added into SAT for bioaugmentation. The feasibility of bioaugmented SAT and associated PNP removal process were investigated by laboratory sand columns, along with effects of the SAT operative parameters (namely PNP loading concentration, flow rate and soil saturation level of SAT). Within the range of PNP loading stresses tested (1-200 mg L^-1), PNP removal efficiency was optimal at constant flow rate of 219 mL d^-1 in unsaturated operating condition of SAT under 15 °C among all the investigated experimental conditions. Longer hydraulic residence time increased the PNP removal rate, although the accumulated mass removed reduced and the removal efficiencies remained constant in unsaturated operating condition of SAT. It is found from the comparison between the PNP removals via both unsaturated and saturated columns that slight difference only in the removal rate of PNP was observed and the highly efficient bioaugmented SAT can completely degrade PNP of 10 mg L^-1 within 5 wetting/drying cycles under both scenarios.

Occurrence and potential human health risks of semi-volatile organic compounds in drinking water from cities along the Chinese coastland of the Yellow Sea

Semi-volatile organic compounds (SVOCs) in drinking water have been considered a severe threat to public health worldwide. However, SVOC contamination and the associated human health risks of the drinking water from cities along tributaries of the Yangtze River and Huaihe River in China have been seldom reported. Here, we focused on the occurrence and distribution of a series of SVOCs, mainly including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and phthalate esters (PAEs), in drinking water of this region. In brief, a total of 31 SVOCs were detectable in all of the drinking water samples, and the total concentrations ranged from 0.92 ng/L to 266.16 ng/L in March and from 24.82 ng/L to 643.93 ng/L in August, with the highest concentrations in Dongtai (DT) and Xinghua (XH), respectively. Spatial and temporal differences of the SVOCs were also observed in drinking water samples, demonstrating the linkage between pollutant profiles and geographical locations, as well as exogenous wastewater discharge. Moreover, PAEs occupied 79.17-100.00% of the total concentrations of SVOCs in drinking water samples collected from the tributaries of the Yangtze River in March, while OCPs were the predominant SVOCs in most of drinking water samples from the tributaries of the Huaihe River. The human health assessment indicated that SVOCs posed negligible non-carcinogenic risks, but residents living in DT, Dafeng (DF), Chengdong (CD), Guanyun (GY) and Lianyungang (LY) may suffer carcinogenic health risks, which could be mainly induced by benzene hexachloride and heptachlor in August.

Water Carcinogenicity and Prevalence of HPV Infection in Esophageal Cancer Patients in Huaihe River Basin, China

Objective

The incidence of the upper gastrointestinal tumor has increased rapidly during recent decades. The relationship between local water pollution and the tumor is still not much clear, so this study was conducted to further investigate the local water pollution and its influence on the malignant cell transformation. Prevalence of human papillomavirus (HPV) in local esophageal cancer (EC) patients was also analyzed in Shenqiu County for the first time.

Methods

Two-step cell transformation was used to study different sources of water in the malignant cell transformation, and the existence of 3-methylcholanthrene (3-MC) in water was analyzed from the river and shallow and deep wells. HPV DNA in tissue samples of EC patients was detected by polymerase chain reaction (PCR) and HPV diagnostic kit.

Results

The river water has higher cytotoxicity than the shallow well water and induced significant cell malignant transformation, while deep well water has not shown the malignant cell transformation. In Huaihe River water, the 3-MC concentration was found higher than shallow and deep wells. An HPV infection rate was found high in patients with esophageal cancer.

Conclusion

Long-term consumption of polluted water can induce malignant cell transformation, and the presence of HPV may be an important cause of cancer.

Human Health Risk Assessment Applied to Rural Populations Dependent on Unregulated Drinking Water Sources: A Scoping Review

Safe drinking water is a global challenge for rural populations dependent on unregulated water. A scoping review of research on human health risk assessments (HHRA) applied to this vulnerable population may be used to improve assessments applied by government and researchers. This review aims to summarize and describe the characteristics of HHRA methods, publications, and current literature gaps of HHRA studies on rural populations dependent on unregulated or unspecified drinking water. Peer-reviewed literature was systematically searched (January 2000 to May 2014) and identified at least one drinking water source as unregulated (21%) or unspecified (79%) in 100 studies. Only 7% of reviewed studies identified a rural community dependent on unregulated drinking water. Source water and hazards most frequently cited included groundwater (67%) and chemical water hazards (82%). Most HHRAs (86%) applied deterministic methods with 14% reporting probabilistic and stochastic methods. Publications increased over time with 57% set in Asia, and 47% of studies identified at least one literature gap in the areas of research, risk management, and community exposure. HHRAs applied to rural populations dependent on unregulated water are poorly represented in the literature even though almost half of the global population is rural.

Linking the environmental loads to the fate of PPCPs in Beijing: Considering both the treated and untreated wastewater sources

The environmental loads of pharmaceutical and personal care products (PPCPs) in Beijing were estimated from direct discharge of untreated wastewater and WWTP treated effluent. The annual environmental loads of 15 PPCP components ranged from 16.3 kg (propranolol) to 9.85 tons (caffeine). A fugacity model was developed to successfully estimate the PPCP pollution based on the estimated environmental load. The modeled results approximated the observed PPCP concentrations in Beijing. The untreated wastewater contributed significantly to PPCP pollution in Beijing, ranging from 46% (propranolol) to 99% (caffeine). The total environmental burden of target PPCPs ranged from 0.90 kg (propranolol) to 536 kg (caffeine). Water is the most important media for the fate of PPCPs. Monte Carlo-based concentration distributions of PPCPs are consistent with the observed results. The most important way to reduce the PPCP pollution is to both improve wastewater collection rate and adopt deep treatment technologies.

Assessment of Industry-Induced Urban Human Health Risks Related to Benzo[a]pyrenebased on a Multimedia Fugacity Model: Case Study of Nanjing, China

Large amounts of organic pollutants emitted from industries have accumulated and caused serious human health risks, especially in urban areas with rapid industrialization. This paper focused on the carcinogen benzo[a]pyrene (BaP) from industrial effluent and gaseous emissions, and established a multi-pathway exposure model based on a Level IV multimedia fugacity model to analyze the human health risks in a city that has undergone rapid industrialization. In this study, GIS tools combined with land-use data was introduced to analyze smaller spatial scales so as to enhance the spatial resolution of the results. An uncertainty analysis using a Monte Carlo simulation was also conducted to illustrate the rationale of the probabilistic assessment mode rather than deterministic assessment. Finally, the results of the case study in Nanjing, China indicated the annual average human cancer risk induced by local industrial emissions during 2002–2008 (lowest at 1.99×10^–6 in 2008 and highest at 3.34×10^–6 in 2004), which was lower than the USEPA prescriptive level (1×10^–6–1×10^–4) but cannot be neglected in the long term.The study results could not only instruct the BaP health risk management but also help future health risk prediction and control.

Application of human cell transformation assay on assessment of carcinogenic potential of river organic pollutants

A human cell transformation assay was used to evaluate the carcinogenic potential of organic extracts of water pollutants collected from the Jialu River.

Perfluoroalkyl substances and organochlorine pesticides in sediments from Huaihe watershed in China

Twelve perfluoroalkyl substances (PFASs) and nine organochlorine pesticides (OCPs) were quantified in surface sediments from the Huaihe River, China, along which there are intensive industrial and agricultural activities. Concentrations of PFASs ranged from 0.06 to 0.46ng/g dry weight (dw), and concentrations of OCPs ranged from 1.48 to 32.65ng/gdw. Compared with other areas in China, concentrations of PFASs were lesser than the national mean value, while concentrations of OCPs were moderate. Concentrations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) ranged from n.d. (not detected) to 0.03 and n.d. to 0.10ng/gdw, respectively. Among the three groups of OCPs, mean concentrations of hexachlorocyclohexane and its isomers (HCHs), dichlorodiphenyltrichloroethane and its metabolites (DDTs) and hexachlorobenzene (HCB) were 5.62±4.35, 2.43±3.12 and 1.55±4.17ng/gdw, respectively. Concentrations of HCHs and DDTs decreased from upstream to downstream along the mainstream of the Huaihe River. When compared to sediment quality guidelines (SQGs), concentrations of HCHs, DDTs and HCB would pose adverse biological effects. In general, contamination by PFASs in the upstream of the Huaihe River was more severe than that in the downstream, which was mainly caused by interception from dams, locks and industrial emissions. And OCPs from tributaries, especially the Yinghe River and Wohe River, were higher than those from Huaihe mainstream, and primarily came from historical inputs.

Human health risks associated with dietary exposure to persistent organic pollutants (POPs) in river water in Korea

Because of their persistence, bioaccumulation tendency, and toxicity, organochlorine pesticides (OCPs) were banned several decades ago. However, they are still detected in natural water and pose a serious risk to human health and the environment. In the present study, seven OCPs were measured in river water collected from 28 sampling sites between 2010 and 2011 in the Yeongsan (YS) and Seomjin (SJ) Rivers, Korea. Gas chromatography/high-resolution mass spectrometry (HRMS) was used for the chemical analysis. The potential health risks of consuming OCPs in fish were assessed in the monitoring region (YS and SJ River basins) by measuring the residual level of OCPs. The human health risks were characterized by considering both the exposure level and the corresponding cancer slope factors; we incorporated both deterministic and probabilistic approaches. The risks were calculated using the probabilistic Maximum Likelihood Estimation (MLE) method. Risk uncertainty and sensitivity were calculated by performing a Monte Carlo analysis. Of the six OCPs, dieldrin, heptachlor epoxide, and hexachlorobenzene exceeded the acceptable risk level in the heavy and light fish consumer groups. The cancer risks associated with these OCPs were 2.99×10(-6), 5.81×10(-6) and 3.72×10(-6), respectively, using the deterministic approach and 1.64×10(-5), 3.36×10(-2) and 5.52×10(-5), respectively, at the 95th percentile using the probabilistic approach. Because there is a high cancer risk associated with these three OCPs, individuals who consume large amounts of freshwater fish may be subject to a high risk of cancer. However, the calculations may have over- or underestimated the risk because of the uncertainty of the environmental concentration and fish intake rate or the use of left-censored monitoring data.

Dietary exposure to persistent organochlorine pesticides in 2007 Chinese total diet study

Dietary exposure to persistent organochlorine pesticides (OCPs) was assessed for Chinese populations, using the total diet study (TDS) approach in 2007. Multistage random cluster sampling method was used in this study. 108 composite samples, representative of foods "as consumed" by the Chinese were analyzed for residues of OCPs by a multi-residue method. The result showed that hexachlorobenzene (HCB), dichloro-diphenyl-trichloroethane (DDT), chlordane compounds (CHLs), hexachlorocyclohexane (HCH) and heptachlor could be detected in, respectively 84%, 39%, 37%, 13% and 5% of all samples. Concentrations of DDT in all samples ranged from undetectable levels to 72.2 μg/kg. Others were minor components in the OCPs profile. The residual levels of OCPs were significantly below the Extraneous Maximum Residue Limits (EMRLs). Based on the 2000 nationwide food consumption survey, the average dietary exposure of the Chinese to DDT, HCH, HCB, CHLs, and heptachlor was estimated to be 0.016, 0.002, 0.009, 0.006, and 0.001 μg/kg body weight per day respectively, showing a significant decrease trend compared with the past. The major food groups contributing to dietary OCPs were aquatic foods, meats, and cereals. The average and high end estimated daily intakes of different OCPs for the Chinese were both lower than the tolerable daily intake (TDI) suggested by authorities indicating low health risk of OCPs dietary exposure among Chinese adults at present. However, the risk of carcinogenicity of the OCPs should be concerned with if the carcinogenicity effects from the exposures to these OCPs were considered.

Development of a strategy for biological monitoring in a chemical plant producing 3,3'-dichlorobenzidine dihydrochloride

In a chemical plant in Germany producing 3,3'-dichlorobenzidine dihydrochloride for the manufacture of colorants, blood and urine samples were taken for biological monitoring. 3,3'-Dichlorobenzidine (DBZ) was analyzed in urine by thin-layer chromatography and subsequently further combined with analysis of adducts of 3,3'-DBZ in hemoglobin. Data highlight current ranges of industrial exposure to 3,3'-DBZ in Germany and demonstrate the applicability of biological monitoring to minimize this exposure. Effective biological monitoring was achieved by a combination of monitoring hemoglobin adducts with spot samplings of urinary 3,3'-DBZ excretion in cases of reported exposure periods. Data presented might help to identify biological guidance values (BGV/BAR) for 3,3'-DBZ-exposed individuals.

Probabilistic ecological risk assessment of DDTs in the Bohai Bay based on a food web bioaccumulation model

The fugacity-based food web model was developed to simulate the bioaccumulation of dichloro-diphenyl-trichloroethanes (DDTs) in the aquatic ecosystem in the Bohai Bay. The internal exposure levels (IELs) of DDTs in various organism categories were calculated. Monte Carlo-based uncertainty analysis was performed to get the of IEL distributions of DDTs in organisms. Probabilistic ecological risk assessment (ERA) was performed based on IEL distributions and internal species sensitivity distributions (SSDs). The results show that fugacities and bioaccumulation factors (BAFs) generally increased with increasing trophic level in the food web. Octanol-water partition coefficient (K(ow)), DDT levels in water and the lipid contents had the greatest influences on IELs in the organism bodies. The ecological risks of DDTs were relatively high. The risk order was p,p'-DDT>p,p'-DDE>p,p'-DDD. At an internal hazard quotient (HQ(int)) criterion of 1/5, the risk probabilities were 0.10 (0.055-0.17), 0.079 (0.045-0.13) and 0.053 (0.028-0.092) for p,p'-DDT, p,p'-DDE and p,p'-DDD, respectively. The results from ERA based on the internal exposure approximated those based on external exposure. The food web model is a feasible method to predict the extent of bioaccumulation and IELs of hydrophobic organic pollutants in organisms as a step to evaluate their risk posed on aquatic ecosystems.