This study presents a longitudinal, integrative assessment of contamination in the Jaguaribe River estuary (Cear & aacute;, Brazil) following the 2019 oil spill, combining chemical, biological, toxicological, and community-engaged approaches. Polycyclic aromatic hydrocarbons (PAHs) and trace elements were quantified in Mytella strigata, alongside physicochemical parameters and genotoxic biomarkers. Total PAHs (& sum;36PAH) ranged from 29.1 to 88.8 mu g/kg wet weight, with molecular distributions indicating a mixed-source profile characterized by a weathered petrogenic signature and episodic pyrogenic inputs. Temporal variability suggested dynamic contamination driven by remobilization and seasonal processes. Despite detectable petroleum-derived compounds, PAHs contributed minimally to human health risk (CR <= 1 & times; 10-5). In contrast, trace elements - particularly arsenic and nickel - were the primary drivers of toxicological concern (CR = 1 & times; 10-3). Although concentrations were generally within regulatory limits, risk assessment indicated low non-carcinogenic but elevated carcinogenic risk, especially under high seafood consumption scenarios typical of local shellfish gatherers. Community-engaged research revealed persistent concerns regarding food safety and institutional response, reflecting awareness of cumulative exposure risks and socio-environmental vulnerability. Overall, this study demonstrates that even low contaminant levels can result in significant health risks when combined with chronic exposure. These findings highlight the need for long-term, multidisciplinary monitoring and context-specific regulatory strategies to protect vulnerable coastal populations.
Tea plantations represent a relatively stable ecosystem, yet improper pesticide use poses significant risks to human and environmental health. This study aimed to assess the risks of major insecticides registered for use in tea plantations to honeybees and non-target arthropods (NTAs). A list of registered active ingredients was compiled, and 11 representative insecticides were selected for primary risk assessment. Data on insecticide use strategies including dosage, number of applications, and application method, along with ecotoxicological characteristics, were collected to calculate predicted exposure concentrations (PEC), predicted no-effect concentrations (PNEC), and acute risk quotients (RQ = PEC/PNEC). For honeybees, only chlorantraniliprole and afidopyropen posed an acceptable risk (RQ <= 1). In contrast, the RQ values for bifenthrin, imidacloprid, clothianidin, malathion and abamectin were 101-585 times higher than acceptable levels. For NTAs, only diafenthiuron, chlorantraniliprole, tolfenpyrad, and afidopyropen posed acceptable risks; while the majority of other insecticides including lambda-cyhalothrin, bifenthrin, imidacloprid, clothianidin, and malathion, exhibited moderate to high risks. These findings indicate that the use of high-risk pesticides in tea plantations should be restricted or phased out. In the interim, adopting mitigation strategies like chemical substitution with low-risk alternatives, optimized application timing, and integrated pest management (IPM) is crucial to protect honeybees, NTAs, and the broader ecosystem.
Heavy metal pollution in traditional handicraft sites has been a significant concern due to its environmental, ecological, and health impacts. This study investigated the accumulation of heavy metals, including As, Cd, Cr, Cu, Zn, Ni, Mn, and Pb in ten cultivated crop species, associated garden and paddy soils, together with related health risks. Heavy metals in 64 crop samples, including rice and leafy vegetables, were analyzed using the ICP-OES. Heavy metal concentrations in ten crops (mg/kg, fresh weight) varied within 0.01-0.09 (As), 0.004-0.01 (Cd), 0.54-2.17 (Cu), 0.04-0.25 (Cr), 2.94-17.2 (Mn), 0.02-0.33 (Ni), 0.002-0.02 (Pb), and 2.62-46.3 (Zn). Although the concentrations of heavy metals in all studied crops were within the thresholds by the European Union, FAO/WHO, and Chinese Ministry of Health, high non-cancer (hazard index, HI = 3.49 for adults and 5.18 for children) and cancer (incremental lifetime cancer risk, ILCR = 1.19 & times;10(-3) for adults and 3.58 & times;10(-4) for children) risks to the exposed community were found. Rice contributes 93.2-94.5% of the total HI and 92.2-94.7% of the total ILCR. Effective remediation of metal-contaminated soils, and careful crop selection or application of amendments were proposed to mitigate these risks.
The excessive eutrophication of surface water will lead to the imbalance of species distribution in water ecosystem, and destroy the flow of material and energy in the system. Detection results of surface water in the Jianghan-Dongting Plain showed that the median concentration of TN was more than 1.60 mg/L, with the excess rate over 60.0%. The TP concentration was not high and the excess rate was less than 10.0% except for Qianjiang. The optimal nitrogen and phosphorus requirements for algae growth in the study area were 1.20 mg/L and 0.07 mg/L respectively, with the most suitable N/P ratio ranging around 16:1. Phosphorus was considered as the limiting factor when N/P exceeded 30:1. Nitrogen was considered as the limiting factor when N/P was less than 10:1. The findings indicated that the plain area between the Yangtze River and the Han River was a high-risk zone, while the southern region of the Yangtze River exhibited the lowest risk of water environment eutrophication. In addition, the risk of eutrophication of water environment was greatly affected by human activities. The findings of this study directly contributed to improving the water ecological security system of the Jianghan-Dongting Plain and provided scientific support for the risk management.
Inrush of acidic mine water from abandoned coal mines poses serious threat to groundwater environment by mobilizing heavy metals and lowering pH, thereby endangering ecosystems and human health. In this study, inrush water samples from nine abandoned coal mines in Wangcang, Sichuan, China, were analyzed for eight heavy metals (Cr(VI), Fe, Mn, Hg, As, Zn, Pb, and Cd) using inductively coupled plasma-mass spectrometry (ICP-MS). The ecological risk was assessed through species sensitivity distribution (SSD) based on native aquatic species data, while health risks were evaluated using USEPA exposure models. Results showed that the mine water was acidic (pH 1.6-7.1) with high metal concentrations, particularly Fe, Zn, Mn, and Cd, with mean values of 1048, 11.5, 4.6, and 0.49 mg/L, respectively, exceeding the Chinese Class III groundwater quality standards. The SSD-derived hazardous concentration for 5% of species (HC5) values ranged from 7.08 & times; 103 mu g/L (Hg) to 3.09 & times; 10(5) mu g/L (Pb), indicating that aquatic species were more sensitive to Hg than Pb. Risk quotients (RQs) revealed Fe as the dominant ecological risk factor across all sites. Although non-carcinogenic hazard indices (HIs) remained below 1, carcinogenic risk from Cr(VI), Cd, and As exceeded the 1 & times; 10(-4) threshold, with oral ingestion identified as the primary exposure pathway. The findings indicate substantial ecological and health risks from abandoned mine inflows, warranting targeted remediation of Fe and carcinogenic metals.
