Pesticides are used worldwide with potential harmful effects on both fauna and flora. The Kibale National Park in Uganda, a site renowned for its biodiversity is surrounded by tea, banana and eucalyptus plantations as well as maize fields and small farms. We previously showed presence of pesticides with potential endocrine disruptive effects in the vicinity. To further investigate the water pollution linked to agricultural pressure in this protected area, we implemented a complementary monitoring strategy based on: analytical chemistry, effects based methods and the deployment of Polar Organic Chemical Integrative Samplers (POCIS). Chemical analysis of the POCIS extracts revealed the presence of 13 pesticides: carbofuran, DEET, 2.4-D amine, carbaryl, ametryn, isoproturon, metolachlor, terbutryn, dimethoate, imidacloprid, picaridin, thiamethoxam, carbendazim, with the first three being present in the largest quantities. Water samples collected at the POCIS sampling sites exhibited thyroid and estrogen axis disrupting activities in vivo, in addition to developmental and behaviour effects on Xenopus laevis tadpoles model. Based on our observations, for the health of local human and wildlife populations, further monitoring as well as actions to reduce agrochemical use should be considered in the Kibale National Park and in regions exposed to similar conditions.

The Marine Monitoring Program (MMP) was established in 2005 to monitor the inshore health of the Great Barrier Reef (GBR) and evaluate progress towards water quality objectives in Reef Water Quality Improvement Plans. The MMP provides information on the magnitude and spatial extent of pesticide contamination, reports on temporal variability, and provides a risk assessment for the biota in the GBR lagoon. However, long-term trends in pesticide contamination of inshore marine waters over the entire monitoring period (2005–2018) have not been assessed. We used up to 14 years of monitoring data for five PSII herbicides (ametryn, atrazine, diuron, tebuthiuron, and hexazinone) to conduct temporal trend analyses at 11 inshore monitoring sites. The trend analyses suggested increasing significant trends (p < 0.05) for the five PSII herbicides concentrations at several monitoring sites. Power analysis indicated that monitoring sites with over 10 years of monitoring data had convincing results with 80% power.

In this study, a multi-residue method was used to analyze 13 pesticides and 1 degradation product in surface and groundwater in the region with the largest sugar cane production in the world. The potential effects of individual pesticides and their mixtures, for aquatic life and human consumption, were evaluated. For the surface water, 2-hydroxy atrazine, diuron, carbendazim, tebuthiuron, and hexazinone were the most frequently detected (100, 94, 93, 92, and 91%, respectively). Imidacloprid (2579 ng L⁻¹), carbendazim (1114 ng L⁻¹), ametryn (1101 ng L⁻¹), and tebuthiuron (1080 ng L⁻¹) were found at the highest concentrations. For groundwater, tebuthiuron was the only quantified pesticide (107 ng L⁻¹). Ametryn, atrazine, diuron, hexazinone, carbofuran, imidacloprid, malathion, carbendazim, and their mixtures presented risk for the aquatic life. No risk was observed for the pesticides analyzed in this work, alone or in their mixtures for human consumption.

Sugarcane is one of the world’s most important commodities. In order to control weeds in the plantations and increase productivity, the mixing of different herbicides during spraying operations is commonplace. This practice is unregulated, and the impact on water quality and nontarget tropical species is poorly understood. In the present work, exposure and recovery assays were used to evaluate antioxidant enzyme activity and histopathological alterations in the liver of tilapia (Oreochromis niloticus) following exposure to mixtures of the herbicides widely used in sugarcane crops: ametryn (AMT), tebuthiuron (TBUT), diuron (DIU), and hexazinone (HZN). The greatest biochemical changes were observed for the mixture (DIU+HZN)+AMT+TBUT at the highest concentration tested (1/10 96hLC50). This mixture caused a significant increase (p < 0.01) of approximately 82% in GST activity after 14 days of exposure. For three of the mixtures evaluated, GST and CAT could be considered potential biochemical biomarkers of exposure to the herbicide mixtures due to the frequency, intensity, and statistical significance of alterations in the assimilation phase. Although morphological changes were evident in the hepatic tissue, severe damage was only noted in a few samples, and there were no statistically significant differences, relative to the control. The results of hepatic lesion recovery assays suggested that the most sensitive individuals affected by the xenobiotics were unable to achieve full recovery. It is anticipated that the data obtained may assist in the selection of biomarkers for monitoring purposes, as well as in reinforcing standards of conduct in the use of agrochemical mixtures in agriculture.

Ametryne is an herbicide applied to sugar cane cultures to prevent the emergence of weeds. It is a persistent compound that percolates ground and surface water thus impacting aquatic communities. In this study, we evaluated microbial activity in soil with increased concentrations of ametryne solution and commercial Microgeo biofertilizer. The soil subject to analysis was obtained from a sugar cane cultivation area. The concentration used in the experiment was ametryne 12 μg/L and 1 % of biofertilizer. It was used with the Bartha and Pramer respirometric method to quantify CO₂production and determine microbial activity. Complimentary phytotoxicity tests with Lactuca sativa seeds after respirometry experiments were conducted in the soluble fraction of the soil. According to the results, the addition of biofertilizer promoted microbial activity in the presence of ametryne and reduced ametryne phytotoxicity for Lactuca sativa seeds. Thus, Microgeo biofertilizer can potentially improve biodegradation of ametryne through both bioaugmentation and bioestimulation.

This paper reports the degradation of 10 mg L⁻¹ Ametryn solution with different advanced oxidation processes and by ultraviolet (UV₂₅₄) irradiation alone with the main objective of reducing acute toxicity and increase biodegradability. The investigated factors included Fe²⁺ and H₂O₂ concentrations. The effectiveness of the UV₂₅₄ and UV₂₅₄/H₂O₂ processes were investigated using a low-pressure mercury UV lamp (254 nm). Photo-Fenton process was explored using a blacklight blue lamp (BLB, λ = 365 nm). The UV₂₅₄ irradiation process achieved complete degradation of Ametryn solution after 60 min. The degradation time of Ametryn was greatly improved by the addition of H₂O₂. It is worth pointing out that a high rate of Ametryn removal was attained even at low concentrations of H₂O₂. The kinetic constant of the reaction between Ametryn and HO● for UV₂₅₄/H₂O₂ was 3.53 × 10⁸ L mol⁻¹ s⁻¹. The complete Ametryn degradation by the Fenton and photo-Fenton processes was observed following 10 min of reaction for various combinations of Fe²⁺ and H₂O₂ under investigation. Working with the highest concentration (150 mg L⁻¹ H₂O₂ and 10 mg L⁻¹ Fe²⁺), around 30 and 70% of TOC removal were reached within 120 min of treatment by Fenton and photo-Fenton processes, respectively. Although it did not obtain complete mineralization, the intermediates formed in the degradation processes were hydroxylated and did not promote acute toxicity of Vibrio fischeri. Furthermore, a substantial improvement of biodegradability was obtained for all studied processes.

Costa Rica is a tropical country with one of the highest biodiversity on Earth. It also has an intensive agriculture, and pesticide runoff from banana and pineapple plantations may cause a high toxicity risk to non-target species in rivers downstream the plantations. We performed a first tier risk assessment of the maximum measured concentrations of 32 pesticides detected over 4 years in the River Madre de Dios (RMD) and its coastal lagoon on the Caribbean coast of Costa Rica. Species sensitivity distributions (SSDs) were plotted in order to derive HC₅ values for each pesticide, i.e., hazard concentrations for 5 % of the species, often used as environmental criteria values in other countries. We also carried out toxicity tests for selected pesticides with native Costa Rican species in order to calculate risk coefficients according to national guidelines in Costa Rica. The concentrations of herbicides diuron and ametryn and insecticides carbofuran, diazinon, and ethoprophos exceeded either the HC₅ value or the lower limit of its 90 % confidence interval suggesting toxic risks above accepted levels. Risk coefficients of diuron and carbofuran derived using local guidelines indicate toxicity risks as well. The assessed fungicides did not present acute toxic risks according to our analysis. Overall, these results show a possible toxicity of detected pesticides to aquatic organisms and provide a comparison of Costa Rican national guidelines with more refined methods for risk assessment based on SSDs. Further higher tier risk assessments of pesticides in this watershed are also necessary in order to consider pesticide water concentrations over time, toxicity from pesticide mixtures, and eventual effects on ecosystem functions.

Triazines and their degradation products are transported to the aquatic environment, and once there, the probability to reach the marine environment is very high. In this paper, solid phase extraction (SPE) and extraction by matrix solid phase dispersion (MSPD) to analyse nine triazines (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine and terbutryn) and eight degradation products (desethylatrazine, desethyldesisopropylatrazine, desethyl-2-hydroxyatrazine, desethylterbuthylazine, desisopropylatrazine, desisopropyl-2-hydroxyatrazine, 2-hydroxyatrazine and 2-hidroxyterbuthylazine) in seawater and marine sediments samples were used. The analysis was carried out using liquid chromatography with tandem mass spectrometry (LC-ESI-MS/MS). The methods were optimized and validated to achieve a selective and sensitive determination of the analytes from different sample, regardless of its complexity. Under the optimum conditions, the proposed methods provided adequate limits of quantification (0.05–0.45 μg L⁻¹ and 0.23–4.26 μg kg⁻¹ in seawater and marine sediments, respectively). Intra- and inter-day relative standard deviation were below 1.41% for all compounds. Recoveries were evaluated, and acceptable values that ranged from 87.5–99.4 and 60.9–99.7% for the seawater and sediment samples, respectively, were obtained. The proposed methods were applied to the analysis of the target compounds in seawater samples and marine sediments from a coastal area of Galicia (NW of Spain).

Ametryn is an herbicide used to control broadleaf and grass weeds and its acute and chronic toxicity is expected to be low. Since toxicological data on ametryn is scarce, the aim of this study was to evaluate rat reproductive toxicity. Thirty-six adult male Wistar rats (90 days) were divided into three groups: Co (control) and T1 and T2 exposed to 15 and 30 mg/kg/day of ametryn, respectively, for 56 days. Testicular analysis demonstrated that ametryn decreased sperm number per testis, daily sperm production, and Leydig cell number in both treated groups, although little perceptible morphological change has been observed in seminiferous tubule structure. Lipid peroxidation was higher in group T2, catalase activity decreased in T1 group, superoxide dismutase activity diminished, and a smaller number of sulphydryl groups of total proteins were verified in both exposed groups, suggesting oxidative stress. These results showed negative ametryn influence on the testes and can compromise animal reproductive performance and survival.

The phytoremediation potential of Brazilian trees species Calophyllum brasiliense, Eremanthus crotonoides, Hymenaea courbaril, Inga striata, and Protium heptaphyllum was investigated for contaminated soils containing ametryn and hexazinone. Visual injury, chlorophyll content, plant height, leaf temperature, leaf number, and water-efficient use were evaluated. Residual herbicides at soil substrates were analyzed by LC/MS. Among the species C. brasiliense and H. courbaril were tolerant to both herbicides. P. Heptaphyllum presented tolerance at ametryn treatment. E. crotonoides, I. striata, and P. heptaphyllum died in hexazinone treatment. A high content of residual ametryn was found for E. crotonoides. In ametryn treatment, residual herbicide has decreased for C. brasiliense and E. crotonoides species. C. brasiliense highlighted among others becoming a good agent for phytoremediation of soils contaminated with traces of ametryn and hexazinone.