Do rainfall characteristics affect the export of copper, zinc and synthetic pesticides in surface runoff from headwater catchments?

Abstract

Rainfall and runoff characteristics may influence off-site export of pesticides into downstream aquatic ecosystems. However, the relationship between rainfall characteristics and pesticide export from small headwater catchments remains elusive due to confounding factors including the application dose and timing and the variation of pesticide stocks in soil. Here we examined the impact of rainfall characteristics on the export of copper (Cu), zinc (Zn) and 12 legacy and currently used synthetic pesticides in surface runoff from a headwater vineyard catchment. Cluster analysis of rainfall intensity, depth and duration of 78 events revealed four distinct rainfall categories, i.e., Small, Long, Moderate and Intense (p<0.001). Event mean concentrations of pesticides did not differ among rainfall categories (p>0.05). In contrast, event loads of both dissolved and solid-bound Cu and Zn significantly differed among rainfall categories (p<0.001). Rainfall depth and intensity significantly correlated with both Cu and Zn loads in runoff (ρ s = 0.33 to 0.92, p<0.002), and might be the main drivers of Cu and Zn export at the catchment scale. In contrast, rainfall depth, intensity or duration did not influence the loads of synthetic pesticides in runoff, even when weekly variations of pesticide stocks in the soil were accounted for. However, intense rainfall-runoff events, that can fragment soil, may control the export of persistent and hydrophobic legacy pesticides stocks in the soil, such as simazine and tetraconazole. Our results emphasise that rainfall characteristics controlled the off-site export of Cu, Zn and legacy synthetic pesticides in a small headwater catchment, whereas the application timing drove the export of currently used synthetic pesticides in runoff. We anticipate our results to be a preliminary step to forecast the influence of regional rainfall patterns on the export of both metallic and synthetic pesticides by surface runoff from small headwater catchments.

Pesticide concentrations in agricultural storm drainage inlets of a small Swiss catchment

“…In contrast to the above-mentioned factors, the discharge transported through the inlets per event did not appear as a significant influencing factor in the model. This aligns well with a study by Imfeld et al ( 2020 ) reporting that the event concentrations at the outlet of a small vineyard catchment were related to the timing of pesticide applications, but not to characteristics of the rain events.…”

Pesticide peak concentration reduction in a small vegetated treatment system controlled by chemograph shape

“…In earlier studies, Lange et al (2011) and observed a 15 %-30 % mass loss of the fluorescent tracer sulforhodamine-B in the wetland subsection of the current VTS. These results indicate a general potential for sorption of organic compounds in this system but represent an earlier succession state of the wetland and stationary flow conditions with much longer residence times.…”

“…Such systems temporally retain polluted waters and thus provide space, time, and favorable conditions for degradation processes. VTSs studied in literature include very different types of systems (Lange et al, 2011), including vegetated ditches or detention ponds with hydraulic residence times (HRT) ranging in the order of minutes to several hours (Bundschuh et al, 2016;Elsaesser et al, 2011;Ramos et al, 2019) or constructed wetlands in which HRT may reach several weeks (Maillard and Imfeld, 2014), particularly when operated in batch mode (Tournebize et al, 2017;Maillard et al, 2016;Moore et al, 2000). The term "pesticide mitigation" can refer to contaminant mass removal (R M ) or peak concentration reduction (R C ).…”

Simple Osthole/Nanocarrier Pesticide Efficiently Controls Both Pests and Diseases Fulfilling the Need of Green Production of Strawberry

“…Nanocarriers with good biocompatibility have been applied extensively in promoting the translocation of drugs across cell membranes for disease treatment. , Similar to medical therapy, some nanoparticles have been used to construct a pesticide delivery system in recent years, and the controlled release of active ingredients (AIs) is particularly important to obtain the maximum biological efficacy and decrease the negative environmental impacts. − Generally, many kinds of adjuvants such as organic solvents, emulsifiers, and dispersants are added to commercial pesticides to increase their biological activity, and large proportions of sprayed pesticides are lost due to photolysis, surface runoff, and spray drift, thus leading to serious environmental pollution and threatening human health. − The AIs of most traditional pesticides are hydrophobic, and the AIs can be encapsulated in nanoparticles or attached to the peripheral groups of nanoparticles, which can increase the dispersion and wettability of AIs, and improve stability of AIs against harsh environmental conditions. − Our group has constructed a series of dendrimer-based nanoparticles consisting of a fluorescent core and periphery amino groups, which can act as a dsRNA/drug carrier to efficiently improve their delivery efficiency. − Furthermore, we construct a star polymer (SPc) without a fluorescent core for large-scale application, which is applied to produce nanoscale botanical/chemical insecticides and increase their insecticidal activity. , …”