Occurrence of emerging contaminants in pet hair and indoor air: integrative health risk assessment using multiple ToxCast endpoints.

Indoor exposome is a growing concern, including a mixture of legacy and emerging contaminants. Recent studies suggest that indoor pollutants may accumulate in pet hair, a part of indoor exposome, increasing health risks to pet owners; however, the source and hazards of pollutants associated with pet hair are largely unknown. Here, we found that hydrophobic pollutants often had higher indoor concentrations than hydrophilic ones, and polycyclic aromatic hydrocarbons (PAHs) were the most dominant fractions (61.1%) in indoor air exposome while polycyclic musks (PCMs) had the highest concentrations among all contaminant classes in indoor dust (1559 ± 1598 ng g-1 dw) and pet hair (2831 ± 2458 ng g-1 dw). The levels of hygiene-related contaminants (PCMs, current-use pesticides (CUPs), and antibiotics) were higher in pet hair than dust due to direct contact during applications. Health risk assessment using toxicity thresholds from high-throughput screening data showed that human health risks from the five classes of indoor contaminants (PAHs, PCMs, organophosphate esters, CUPs, and antibiotics) via inhalation, ingestion, and dermal contact were within acceptable limits, but the children may be exposed to a higher risk than the adults. The thresholds estimated from the ToxCast data using endpoint sensitivity distribution make the exposome risk assessment feasible in the absence of benchmarks, which is beneficial for including a mixture of emerging pollutants in risk assessment.

Analysis of the Spatial Relationship between Ecosystem Regulation Services and Rural Tourism.

In the context of China's implementation of the rural revitalization strategy and establishment of a mechanism to realize the value of ecological products, rural tourism as an eco-friendly industry promotes regional social and economic development with high-quality natural and ecological conditions in rural areas and is one of the key patterns to realize regional green development. Existing studies in the field focus on the spatial relationship between rural tourism and traditional factors such as economy, population, and transportation and ignore to some extent the relationship between ecosystem services and rural tourism. However, from the perspective of distribution, rural tourism is popular mainly in areas with high ecological quality, so it can be inferred that there is a relationship between ecosystem services and rural tourism. Therefore, this paper targets the key problem-the spatial relationship between ecosystem regulation services and rural tourism, taking rural tourist spots in six districts and counties in the Wuling Mountains in southeastern Chongqing as the subjects, and using the geo-econometric analysis method and geographic detector model to analyze the spatial-driving and development-support roles of ecosystem services on rural tourism. The results show that: (1) the nearest neighbor index of the distribution of rural tourist spots in the regions of study is 0.28, showing a significant clustering trend as a whole; (2) there are obviously high-value areas among the six types of ecosystem regulation services, which are mainly distributed in forest ecosystems; (3) the driving effects of dual factors are more significant, and the combined driving effects of climate regulation and anion supply services are the most significant, with the q value of these driving effects being 0.1962; (4) from the perspective of the supply-demand relationship of industrial development, ecosystem services play an important role in supporting the development of rural tourism. Based on these results, it is proposed in this paper that, in the next step, a comprehensive analysis of the impact of ecosystem regulation services should be conducted during the special planning of rural tourism and the rational layout of industries should be guided on the premise of compliance with space-use control, as well as economical and intensive land use, to support the scientific formulation of regional rural tourism development strategies with new ideas based on basic analysis and better realize the value of ecological products and boost rural revitalization.

UV-dependent freshwater effect factor of nanoscale titanium dioxide for future life cycle assessment application.

Environmental impacts of nanoscale titanium dioxide (TiO2 ) should be assessed throughout the lifetime of nanoparticles (NPs) to improve the state of knowledge of the overall sustainability. Life cycle assessment (LCA) has been previously recognized as a promising approach to systematically evaluating environmental impacts of NPs. As a result of their unique nanospecific properties, characterization factors (CF) were previously used for compensating the release and potential impacts of TiO2 NPs. However, because TiO2 NPs are known to generate reactive oxygen species and elicit toxicity to freshwater organisms, the lack of adequate UV-dependent effect factors (EFs) remains a major shortcoming when addressing their life cycle impacts. To complement the LCA of TiO2 -NPs-enabled products under their specific applications, we recapitulated the freshwater toxicity of TiO2 NPs and then modeled in USEtox to determine trophic level EF ranges under UV and non-UV exposure conditions. Results indicate that EFs derived for non-UV exposure were 52 (42.9-65) potentially affected fraction (PAF) m3 /kg, and combined toxicity data derived EFs were 70.1 (55.6-90.5) PAF m3 /kg. When considering only the UV-induced exposure condition, the modeled EF increased to 500 (333-712) PAF m3 /kg. Our work highlights that case-dependent EFs should be considered and applied to reflect more realistic ecological impacts and illustrate comprehensive life cycle environmental impacts for nanoenabled products. Integr Environ Assess Manag 2023;19:578-585. © 2022 SETAC.

Anti-social behaviour and economic decision-making: Panel experimental evidence in the wake of COVID-19.

We systematically examine the acute impact of exposure to a public health crisis on anti-social behaviour and economic decision-making using unique experimental panel data from China, collected just before the outbreak of COVID-19 and immediately after the first wave was overcome. Exploiting plausibly exogenous geographical variation in virus exposure coupled with a dataset of longitudinal experiments, we show that participants who were more intensely exposed to the virus outbreak became more anti-social than those with lower exposure, while other aspects of economic and social preferences remain largely stable. The finding is robust to multiple hypothesis testing and a similar, yet less pronounced pattern emerges when using alternative measures of virus exposure, reflecting societal concern and sentiment, constructed using social media data. The anti-social response is particularly pronounced for individuals who experienced an increase in depression or negative affect, which highlights the important role of psychological health as a potential mechanism through which the virus outbreak affected behaviour.

Amphetamine-type stimulants use and socio-economic factors associated with hepatitis C antibody positivity among border drug users in South of China.

Background: Amphetamine-type stimulants (ATS) use has become popular in China. This study explored ATS use status and related risk factors of hepatitis C virus (HCV) infection among ATS users in Jinghong City, Xishuangbanna Prefecture, Yunnan Province, China. Methods: A cross-sectional study was conducted by questionnaires from January to July 2021 in border area in Yunnan. Respondent driving sampling and consecutive sampling was carried out among border drug users, and blood samples were tested for HCV antibodies. HCV infection and related risk factors among ATS users were measured. Descriptive, univariate and multivariate analysis were conducted separately by Software SPSS 26.0. Results: The ATS users accounted for 85.82% (345/402) among drug users, while anti-HCV antibody prevalence was 6.38% (22/345) among ATS users. The combined use of other types of drugs (OR = 7.29, 95%CI: 1.982-26.81, P = 0.003), injection drug use (OR = 6.823, 95%CI: 1.898-24.525, P = 0.003), average monthly income (OR = 4.825, 95%CI: 1.325-17.566, P = 0.017) might increase the risk of HCV infection among ATS users. ATS users with high school or above had higher HCV infection rates than those with primary school or below (OR = 5.718, 95%CI: 1.172-27.908, P = 0.031). Conclusion: Taken together, among drug users using ATS in Jinghong City, Xishuangbanna Autonomous Prefecture, Yunnan Province, combined use of multiple drugs and intravenous drug use was the high risk factor for HCV infection. Therefore, corresponding education and intervention measures should be taken.

The Operation Mode of Agricultural Supply Chain Finance Using Blockchain.

With the rapid development of agriculture, modern agriculture has achieved remarkable results. Agriculture is the foundation of China's national economy, and the Party Central Committee has always insisted on solving the "three rural issues" as the top priority of the work of the whole party. However, China's agricultural foundation is weak, and the problem of unbalanced supply and demand structure of agricultural products still exists in agricultural development. With the development of blockchain, the application basis in the agricultural value chain has been established. At present, the research on the application of agricultural value chain financing is still in progress, but it is still in the initial stage. The integration of agricultural finance blockchain is low, and there are a series of problems. Extending blockchain technology to the financial area of agricultural value chains can help overcome the information barriers to traditional agricultural value chain financing and improve access to information resources for traditional agricultural value chains. The high cost of these value chains and inadequate financial management mechanisms remove bottlenecks in financing agricultural development. In this paper, we study the operation model and revenue distribution model of agricultural value chains using blockchain, analyze examples, and finally identify the basic elements of agricultural value chain financing based on sectoral chain technology. It provides theoretical support for the financing decision and production decision of each member of the agricultural supply chain, and it is hoped that the content and conclusions of the study can provide methodological reference and theoretical guidance for agricultural supply chain enterprises.

Deriving freshwater guideline values for neonicotinoid insecticides: Implications for water quality guidelines and ecological risk assessment.

The increased use of neonicotinoid insecticides in aquatic environments poses a significant threat to non-target freshwater species. However, the existing water quality guidelines (WQGs) for neonicotinoids mainly focus on imidacloprid, and only a few authoritative institutions have established WQGs for other neonicotinoids. There is a critical need to develop WQGs and conduct ecological risk assessment (ERA) of different neonicotinoids in global freshwater environments. In this study, we derived interim acute and chronic guideline values and acute-to-chronic ratios (ACRs) for six neonicotinoids based on publicly available acute and chronic toxicity data. The exposure concentrations of neonicotinoids were obtained from published literature worldwide, and ERA was conducted for neonicotinoids in global freshwater ecosystems using a tiered approach. The derived chronic guideline values (95% confidence interval (CI), ng/L) were 0.63 (0.02-5.47) for thiacloprid (the lowest) and 16.4 for dinotefuran (the highest). The identified ACRs (95% CI) ranged from 90.9 (47.0-180) to 957 (102-3350), which can be used to extrapolate scarce chronic data from the acute data. Neonicotinoid concentrations in global freshwater were predicted from 10.6 (6.88-23.4) (thiacloprid) to 339 (211-786) ng/L (thiamethoxam). The estimated risk quotients ranged from 3.23 (dinotefuran) to 21.73 (thiacloprid), and the probability of exceeding WQGs ranged from 27.1% (dinotefuran) to 77.1% (thiacloprid). The ERA results indicated that the six neonicotinoids posed negligible acute risks but high chronic risks to global freshwater ecosystems, especially acetamiprid (65.8%) and thiacloprid (28.1%). The key findings of this study provide critical scientific information regarding the ecological risks of long-term neonicotinoid exposure and key insights for policy development and water quality control.

Toward Sustainable Environmental Quality: Priority Research Questions for Asia.

Environmental and human health challenges are pronounced in Asia, an exceptionally diverse and complex region where influences of global megatrends are extensive and numerous stresses to environmental quality exist. Identifying priorities necessary to engage grand challenges can be facilitated through horizon scanning exercises, and to this end we identified and examined 23 priority research questions needed to advance toward more sustainable environmental quality in Asia, as part of the Global Horizon Scanning Project. Advances in environmental toxicology, environmental chemistry, biological monitoring, and risk-assessment methodologies are necessary to address the adverse impacts of environmental stressors on ecosystem services and biodiversity, with Asia being home to numerous biodiversity hotspots. Intersections of the food-energy-water nexus are profound in Asia; innovative and aggressive technologies are necessary to provide clean water, ensure food safety, and stimulate energy efficiency, while improving ecological integrity and addressing legacy and emerging threats to public health and the environment, particularly with increased aquaculture production. Asia is the largest chemical-producing continent globally. Accordingly, sustainable and green chemistry and engineering present decided opportunities to stimulate innovation and realize a number of the United Nations Sustainable Development Goals. Engaging the priority research questions identified herein will require transdisciplinary coordination through existing and nontraditional partnerships within and among countries and sectors. Answering these questions will not be easy but is necessary to achieve more sustainable environmental quality in Asia. Environ Toxicol Chem 2020;39:1485-1505. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Full-Life Cycle Toxicity Assessment of Sediment-Bound DDT and Its Degradation Products on Chironomus dilutus.

Because of its hydrophobicity and persistence, dichlorodiphenyltrichloroethane (DDT) is ubiquitous in sediments and poses significant risk to benthic organisms. Therefore, it is imperative to evaluate the long-term toxicity of DDT. However, limited information is available on its chronic toxicity to benthic invertebrates. Full-life cycle toxicity of sediment-bound DDT to Chironomus dilutus was assessed. Median lethal concentrations (with 95% confidence limits) of DDT and its degradation products (DDX) to C. dilutus were 334 (165-568), 21.4 (11.2-34.3), and 7.50 (4.61-10.6) nmol/g organic carbon after 10-, 20-, and 63-d exposure, respectively. In addition, median effect concentrations of DDX were 20.0 (15.0-25.3), 7.13 (4.10-10.5), and 8.92 (3.32-15.1) nmol/g organic carbon for growth, emergence, and reproduction, respectively. A toxicity spectrum was established to visually summarize chronic effects of DDX to midges. In addition, DDT degraded to dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE) during sediment aging, and their toxicity differed from that of the parent compound. Predicted toxic units of DDX in porewater were utilized to distinguish between toxicity from DDT and that of DDD and DDE. The results showed that DDD was the main contributor to the toxicity in C. dilutus. To improve the accuracy of sediment risk assessment of DDT, the composition of DDX should be considered. Environ Toxicol Chem 2019;38:2698-2707. © 2019 SETAC.

Rationale and study design for one-stop assessment of renal artery stenosis and renal microvascular perfusion with contrast-enhanced ultrasound for patients with suspected renovascular hypertension.

BACKGROUND: Renal artery stenosis (RAS) is always associated with abnormalities in renal microvascular perfusion (RMP). However, few imaging methods can simultaneously evaluate the degree of luminal stenosis and RMP. Thus, this study will aim to evaluate the feasibility of using contrast-enhanced ultrasound (CEUS) for assessing both RAS and RMP to achieve a one-stop assessment of patients with suspected renovascular hypertension. METHODS: This will be a single-center diagnostic study with a sample size of 440. Patients with chronic kidney disease (CKD) and suspected of having resistant hypertension will be eligible. Patients with Stages 1-3 CKD will undergo CEUS and computed tomography (CT) angiography (CTA). Values obtained by CEUS and CTA for diagnosing low-grade (lumen reduced by <60%) and high-grade (lumen reduced by ≥60%) RAS will be compared. Moreover, all patients will also undergo radionuclide imaging. The diagnostic value for RAS will be assessed by the receiver operating characteristic curve, including the accuracy, sensitivity, specificity, positive predictive values, negative predictive values, and area under the ROC. Pearson correlation analysis will be performed to assess the association between CEUS findings for RMP and glomerular filtration rate measured by a radionuclide imaging method. CONCLUSION: The data gathered from this study will be used to evaluate the feasibility of expanding clinical applications of CEUS for evaluation of patients with suspected renovascular hypertension. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800016252; https://www.chictr.org.cn.

Effects of Financial Incentives on Saving Outcomes and Material Well-Being: Evidence From a Randomized Controlled Trial in Uganda.

The use of savings products to promote financial inclusion has increasingly become a policy priority across sub-Saharan Africa, yet little is known about how families respond to varying levels of savings incentives and whether the promotion of incentivized savings in low-resource settings may encourage households to restrict expenditures on basic needs. Using data from a randomized controlled trial in Uganda, we examine: 1) whether low-income households enrolled in an economic-empowerment intervention consisting of matched savings, workshops, and mentorship reduced spending on basic needs and 2) how varied levels of matching contributions affected household savings and consumption behavior. We compared primary school-attending AIDS-affected children (N = 1,383) randomized to a control condition with two intervention arms with differing savings-match incentives: 1:1 (Bridges) and 1:2 (Bridges PLUS). We found that: 1) 24 months post-intervention initiation, children in Bridges and Bridges PLUS were more likely to have accumulated savings than children in the control condition; 2) higher match incentives (Bridges PLUS) led to higher deposit frequency but not higher savings in the bank; 3) intervention participation did not result in material hardship; and 4) in both intervention arms, participating families were more likely to start a family business and diversify their assets.

Improvements and cost-effective measures to the automated intermittent water renewal system for toxicity testing with sediments.

The push to make bioassays more sensitive has meant an increased duration of testing to look at more chronic endpoints. To conduct these longer bioassays through the use of traditional bioassay methods can be difficult, as many traditional bioassays have employed manual water changes, which take considerable time and effort. To that end, static-renewal systems were designed to provide researchers a technique to ease the manual water change burden. One of the most well-known static-renewal designs, the static intermittent renewal system (STIR) was produced by the United States Environmental Protection Agency in 1993. This system is still being used in laboratories across the globe today. However, these initial designs have become rather dated as new technologies and methods have been developed that make these systems easier to build and operate. The following information details changes to the initial design and a proof of concept experiment with the benthic invertebrate, Chironomus tepperi, to validate the modifications to the original system.

Early Surgery Confers 1-Year Mortality Benefit in Hip-Fracture Patients.

BACKGROUND: To evaluate the relationship between surgical timing and 1-year mortality in patients requiring hip fracture repair. METHODS: We analyzed all 720 patients (>65 years) who had hip fracture surgery between March 2005 and February 2015, identifying patients by ICD-9 diagnosis and procedure codes using electronic data query. Mortality data were obtained from the institutional database, state and Social Security Death Indices. The relationship between surgical timing (defined as the interval from admission to the start of surgery) and 1-year mortality was assessed using a multivariable logistic regression, adjusting for baseline clinical status and surgical factors. RESULTS: Among the 720 patients, 159 patients (22%) died within 1 year. The median time from admission to surgery was 30 hours. A linear relationship between the surgical timing and 1-year mortality was demonstrated. Delaying surgery was significantly associated with increased 1-year mortality, odds ratio 1.05 (95% CI: 1.02-1.08) per 10-hour delay (P = 0.001). CONCLUSIONS: A linear relationship was observed between surgical timing and 1-year mortality. Each 10-hour delay from admission to surgery was associated with an estimated 5% higher odds of 1-year mortality. Therefore, we suggest that hip fractures should be treated urgently similar to other time-sensitive pathology such as stroke and myocardial ischemia. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Can socio-economic differences explain low expectation of health services among HIV patients compared to non-HIV counterparts?

BACKGROUND: The health service of China has encountered significant challenges due to inequalities in socio-economic determinants of health. HIV patients are known to suffer from social stigma, and may receive inadequate responsiveness from health providers. Before assessing the responsiveness they receive, it is important to know their expectations. We aimed to compare levels of expectation towards the healthcare service among HIV and non-HIV patients with adjustment for socio-economic factors. METHODS: A cross-sectional study was conducted during January and February, 2015 among two consecutive groups of HIV positive and non-HIV patients in two hospitals in Kunming, China. Patients' expectation towards eight domains of health system responsiveness was measured using 40 vignettes; five per domain. Each vignette was ranked from 1 "very good" to 5 "very bad", and the responses were summed to obtain a total score for each domain. Differences in total scores were compared between the two groups and adjusted for other factors using multiple linear regression. RESULTS: The three domains with the highest scores, reflecting high expectation, were prompt attention, basic amenities and choice. Adjusted for other factors, HIV patients had significantly lower levels of expectation in all domains compared to the non-HIV group. Age was associated with the basic amenities domain, with young adults having higher expectations than other age groups. Minority ethnic groups had lower expectation towards dignity, prompt attention and autonomy domains compared to Han ethnicity. Those who lived in a home with 2-4 family members had higher expectations towards confidentiality than those who lived alone. CONCLUSION: Patients with HIV have significantly lower levels of expectations even after adjusting for socio-economic factors. Assessment of health system responsiveness based on their judgments above may give biased results toward favorable service quality.

Lending to Parents and Insuring Children: Is There a Role for Microcredit in Complementing Health Insurance in Rural China?

This paper assesses the causal impact on child health of borrowing formal microcredit for Chinese rural households by exploiting a panel dataset (2000 and 2004) in a poor northwest province. Endogenous borrowing is controlled for in a dynamic regression-discontinuity design creating a quasi-experimental environment for causal inferences. There is causal relationship running from formal microcredit to improved child health in the short term, while past borrowing behaviour has no protracted impact on subsequent child health outcomes. Moreover, formal microcredit appears to be a complement to health insurance in improving child health through two mechanisms-it enhances affordability for out-of-pocket health care expenditure and helps buffer consumption against adverse health shocks and financial risk incurred by current health insurance arrangements. Government efforts in expanding health insurance for rural households would be more likely to achieve its optimal goals of improving child health outcomes if combined with sufficient access to formal microcredit.

Assessment of Sediment Risk in the North End of Tai Lake, China: Integrating Chemical Analysis and Chronic Toxicity Testing with Chironomus dilutus.

Whole life-cycle bioassays with Chironomus dilutus were performed to evaluate sediment toxicity in Tai Lake, a typical freshwater lake in China. Meanwhile, contaminants of concern were analyzed in sediment. The sediments in Tai Lake showed no acute mortality in 10-day testing to C. dilutus. After chronic exposure to the sediments, however, adverse effects-including decreased survival and sublethal impairments of growth, emergence, and fecundity-were observed at most sites in Tai Lake. A variety of contaminants were detected in sediment with the total concentrations in the range of 504-889 ng/g dry weight (dw) for polycyclic aromatic hydrocarbons, 0.56-1.81 ng/g dw for polychlorinated biphenyls, 38.6-87.8 ng/g dw for polybrominated diphenyl ethers, 8.34-14.2 ng/g dw for organochlorine pesticides, 1.27-2.95 ng/g dw for organophosphate pesticides, 0.11-0.21 ng/g dw for pyrethroid pesticides, and 332-609 µg/g dw for metals. Finally, a canonical correlation analysis was applied to link chronic sediment toxicity to the toxic units of individual contaminants. Results suggested that two pesticides (hexachlorocyclohexane and chlorpyrifos) and two metals (chromium and nickel) in sediments from Tai Lake were the potential contributors to the noted toxicity in C. dilutus in the life-cycle toxicity testing. In conclusion, acute bioassays with the benthos were not sensitive enough to assess sediment toxicity in freshwater lakes in China, and it is desirable to integrate chronic toxicity testing with chemical analysis to better understand sediment risk.

Integrated sediment quality assessment through biomarker responses and bioavailability measurements: Application in Tai Lake, China.

A weight of evidence (WoE) framework has been applied to assess sediment quality of a typical freshwater lake, Tai Lake in China, where the sediments were contaminated by various chemicals but showed no acute lethality to the benthic invertebrate, Chironomus dilutus. A quantitative scoring method was employed to integrate three lines of evidence (LoE), including adverse effects in life cycle bioassays, biomarker responses, and bioavailability-based chemical analysis. Six biomarkers were determined in C. dilutus after the exposure to the sediments from Tai Lake and provided sensitive indication of sublethal effects at the molecular level. The biomarkers included cytochrome P450, glutathione S-transferase, carboxylesterase, acetylcholinesterase, catalase, and lipid peroxidation. The changes of the biomarkers were summarized for individual sampling sites by computing the integrated biomarker response (IBR) indices. Complementary information was also confirmed by the interrelationship of the LoEs. The IBR indices gained before pupation correlated well with the impairments of emergence of the midges, and altered acetylcholinesterase was corroborated by the detection of chlorpyrifos, an organophosphate pesticide. The relationship between bioavailable toxic units estimated by Tenax extractable concentrations of chemicals in sediment and the observed toxicity in the midges helped to identify the putative toxicity contributors to C. dilutus. Overall, the WoE method clearly distinguished the contaminated sites and ranked them by the level of contamination. Sediment-associated pesticides, particularly γ-hexachlorocyclohexane and chlorpyrifos, were the possible contributors to chronic toxicity to the midges.

Application of species sensitivity distribution in aquatic probabilistic ecological risk assessment of cypermethrin: a case study in an urban stream in South China.

A tiered ecological risk assessment was applied to quantitatively refine the overall probabilistic risk of cypermethrin, a pyrethroid insecticide, to aquatic organisms. These results were then validated through the bioassays using field water from an urban stream, Chebei Creek in Guangzhou, South China. Seventeen water samples were collected along Chebei Creek for evaluation. In total, 71% of the field waters were acutely toxic to Hyallela azteca and 24% of the waters caused 100% mortality. Toxic unit evaluation suggested that cypermethrin was one of the main contributors to toxicity. The tiered ecological risk assessment approach (deterministic quotient method and probabilistic methods, including joint probability curve and Monte Carlo Simulation) suggested that cypermethrin posed significant threats to aquatic ecology in this stream. The overall probabilistic risk of cypermethrin to aquatic species in Chebei Creek reached 66% when acute-to-chronic ratios were set at 125. An exceedance probability of cypermethrin in Chebei Creek that affected H. azteca as modeled using the joint probability curve method was 88%, suggesting that most sites were at risk due to cypermethrin exposure. This value was similar to the results obtained from acute toxicity tests (71% of field water samples were acutely toxic to H. azteca), indicating the effectiveness of the tiered approach to assess risk of cypermethrin in urban waterways. To the authors' knowledge, the present study is the first to provide a focused probabilistic evaluation of ecological risk for cypermethrin in a complex urban waterway environment. Despite uncertainties existing in the ecological risk assessment procedure, this approach provides a comprehensive assessment of ecological risk of cypermethrin, and subsequently, a foundation for further risk diagnosis and management in urban waterways.

Inter-compartmental transport of organophosphate and pyrethroid pesticides in South China: implications for a regional risk assessment.

The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air-water flux, including air-water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air-water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data.