Spatiotemporal distribution of veterinary and human drugs and its predictability in Japanese catchments

One Health approach: Addressing data challenges and unresolved questions in agriculture

The One Health approach, which seeks to balance the health of people, animals, and ecosystems, is gaining increasing recognition. Although in 2022 the One Health High-Level Expert Panel refined its definition to explicitly include plant health, concrete integration of crop health into One Health strategies remains underdeveloped. As a result, the agricultural domain's contributions to the environmental chemical load are still insufficiently addressed. In addition, there is a general lack of studies aimed at estimating the relative contribution of each different One Health domain (i.e., the human, the animal, and the plant one) to this phenomenon. This discussion paper examines the current availability of data on main chemical outputs across these domains, specifically focusing on agrochemical and drug/medicine use in agriculture, animal, and human health. However, data collection proved challenging due to inconsistencies and gaps across sectors, making direct comparisons of environmental burdens difficult to establish. Instead, this study provides an indication of trends while primarily highlighting severe gaps in data availability and the unanswered research questions that arise from them. It also emphasizes the necessity of interdisciplinary collaboration across all three domains. In particular, the integration of scholars, professionals, and experts in agriculture, forestry, livestock and environmental sciences is crucial to optimizing future One Health initiatives, especially in the context of crop and plant health.

Evaluation of a specific system of extended producer responsibility for veterinary medicines packaging waste

In Portugal, packaging products for veterinary medicines (VM) are subjected to the extended producer responsibility (EPR) scheme coordinated by a Producer Responsibility Organisation (PRO), responsible for the management of both human and VM packaging waste. Despite an 80% recycling target for VM packaging waste, recent years have consistently shown performance below this level. However, there is no compositional data on VM packaging waste in scientific literature, hindering effective problem diagnosis and solution proposals. So, this research proposes a protocol to characterise VM packaging waste entering and leaving a sorting centre and presents the corresponding results. Of the 822.1 kg entering the centre, glass is the predominant material (66.7%, in weight). Often, glass has rubber and metal attached, but this is not recognised as a constraint on recyclability by the glass recycling industry. Biohazardous VM waste was found in the containers dedicated to pharmacologic VM waste, raising a challenge. To evaluate alignment with the principles of circularity, opportunities for waste reduction were assessed but found to be limited by stringent VM regulations. Nevertheless, the potential for recycling could be enhanced through adjustments to the sorting procedures. Moreover, future research should prioritise biohazard risks and operational aspects of recyclability. In addition, discussion and potential reconsideration of recycling rate targets for this waste category are recommended.

Factors affecting mass inflow of quaternary ammonium compounds into Japanese sewage treatment plants

Quaternary ammonium compounds (QACs), ecotoxic organic chemicals linked to multidrug resistance, are being used increasingly, for example to prevent the transmission of infections such as covid-19, in households, hospitals, and industry. To understand the locations, fluctuations, and fractions of QACs entering sewers, we monitored 14 QACs (benzalkonium chloride [BAC]-C8, C10, C12, C14, C16, and C18; dialkyldimethylammonium chloride [DDAC]-C8, C10, and C12; alkyltrimethylammonium chloride [ATAC]-C12, C16, and C18; benzethonium chloride; and cetylpyridinium chloride), and a disinfectant (chlorhexidine) in influent at four Japanese sewage treatment plants (STPs) five times throughout a year. Mass inflows were relatively stable throughout the year, indicating that the recent seasonal covid-19 epidemic did not greatly influence them. The differences in mass inflows among the STPs were normalized successfully by sewered residential population (most relative SDs were <30%), implying households to be the main source. Per-capita mass inflows accounted for 58%-73% of the per-capita consumption of BAC-C12 + C14 + C16, 28%-59% of that of DDAC-C10, 52%-70% of that of ATAC-C12, 86%-99% of that of ATAC-C16, and 64%-82% of that of ATAC-C18, indicating that a large proportion of their consumption entered sewers. The high contribution of ATAC-C16 agreed with its limited use in primary and secondary industries, little of whose wastewaters enter sewers, whereas the low contribution of DDAC-C10 is attributable to its substantial use in animal husbandry. Our first observation of fractions of QACs entering sewers will advance the management of environmental risks.

Occurrence and source identification of the disinfectant didecyldimethylammonium chloride in a Japanese watershed receiving effluent from swine farms

Didecyldimethylammonium chloride (DDAC), a toxic quaternary ammonium compound (QAC) linked to multidrug resistance, is used widely in households and hospitals and on swine farms to prevent disease transmission. However, little is known about its occurrence in watersheds receiving livestock wastewaters or manure. We monitored DDAC and tracers (veterinary and human drugs) once a season over a year at 14 sites in a Japanese watershed where swine outnumbered humans 1.2 to 1 and where both swine and human wastewaters were largely treated on site. DDAC concentrations in sewage-treatment-plant effluent (33-52 ng/L) were close to, whereas those in river waters (3.6-16,672 ng/L) far exceeded, those reported worldwide. DDAC mass flows at the catchment outlet (1692-3816 μg/s) were higher than those of any of the drugs. DDAC concentrations were significantly correlated with total concentrations of veterinary drugs (Spearman's correlation coefficient, 0.95, P < 0.01), indicating that the major pathway of DDAC entry to surface waters was via effluent discharge from swine farms. Comparison of observed and predicted mass flows implied that a substantial percentage of DDAC was washed from the barn floor into swine excrement. To our knowledge, this is the first study to demonstrate QAC hotspots attributable to animal husbandry.

Comprehensive evaluation of antibiotics pollution the Yangtze River basin, China: Emission, multimedia fate and risk assessment

Antibiotics have attracted global attention because of their potential ecological and health risks. The emission, multimedia fate and risk of 18 selected antibiotics in the entire Yangtze River basin were evaluated by using a level Ⅳ fugacity model. High antibiotic emissions were found in the middle and lower reaches of the Yangtze River basin. The total antibiotic emissions in the Yangtze River basin exceeded 1600 tons per year between 2013 and 2021. The spatial distribution of antibiotics concentration was the upper Yangtze River > middle Yangtze River > lower Yangtze River, which is positively correlated with animal husbandry size in the basin. Temperature and precipitation increases may decrease the antibiotic concentrations in the environment. Transfer fluxes showed that source emission inputs, advection processes, and degradation fluxes contributed more to the total input and output. High ecological risks in the water environment were found in 2018, 2019, 2020, and 2021. The comprehensive health risk assessment through drinking water and fish consumption routes showed that a small part of the Yangtze River basin is at medium risk, and children have a relatively high degree of health risk. This study provides a scientific basis for the pollution control of antibiotics at the basin scale.

Localized pollution of veterinary antibiotics in watersheds receiving treated effluents from swine farms

Swine excrement is discharged into surface waters mainly as effluent in Asian countries. As swine production consumes more antibiotics and less water than humans, a mismatch of the size of swine farms and that of the rivers receiving their effluent could create severe pollution by antibiotics. However, little is known about the occurrence of antibiotics in such rivers. We therefore monitored seven veterinary drugs, six human drugs (including a metabolite), three drugs for both use (including a metabolite), and major water qualities at 30 sites in Japanese watersheds where swine outnumber humans and where their excrement is largely treated on-site by aerobic biological wastewater processes. The compositions of veterinary drugs differed substantially among sites, unlike human drugs, indicating various patterns of use among swine farms. Median concentrations at the 30 sites were <1 ng/L for seven out of the ten drugs used in livestock, whereas maximum concentrations were >1000 ng/L for three and 100-1000 ng/L for four of them, giving median-maximum among the sites of >3 log for two and 2-3 log for six of them. The spatial distribution ranges of concentrations of veterinary drugs were wider than those of human drugs (mostly <1.5 log) and other analytes (mostly <1 log), despite the correlation between those of total veterinary drugs and nitrogen, attributable to fewer swine farms than households, the intensive animal husbandry, and the various drug-use patterns among the farms. The range of maximum concentrations of veterinary drugs in the watersheds was comparable to those reported in other Asian watersheds with less strict management of swine excrement, attributable to their slow decay in conventional wastewater treatment on swine farms. Thus, attention should be paid to hot-spot pollution of antibiotics on large Asian swine farms adjacent to streams with limited dilution capacity.