Pesticides from the EU First and Second Watch Lists in the Water Environment

Abstract

The contamination of water with pesticides used in agriculture and urban areas is a priority issue that is currently of global concern. In 2015, the European Union (EU) published the first Watch List (1st WL), which showed the necessity for Union‐wide monitoring of ten organic substances/groups of substances in the field of water policy. The list includes, among other items, eight pesticides: five neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam), and methiocarb, oxadiazon, and tri‐allate. In 2018 the EU published the second Watch List, which repealed the 1st WL. In this list, among other changes, one pesticide (metaflumizone) was added, and two (oxadiazon and tri‐allate) were removed. This review summarizes the current state of knowledge on the reported occurrence and concentrations of these pesticides in surface and groundwaters and in effluents from wastewater treatment plants derived from 73 studies in 21 countries worldwide. Imidacloprid, acetamiprid and thiamethoxam were the most frequently found pesticides due to their widespread use, while metaflumizone, methiocarb, oxadiazon, and tri‐allate are less studied pesticides whose occurrence in water is also poorly reported. More investigation is needed to assess the occurrence and impact of these pesticides on the aquatic environment worldwide in the context of water supply and human security.

Chronic effects of a binary insecticide Acer 35 EC on Nile tilapia Oreochromis niloticus through a multi-biomarker approach

“…In the world, the reported concentrations of acetamiprid residues detected in water ecosystems are respectively 6.31 mg/L in Brazil, 34.4 ng/L in China and 40 ng/L in the United States (Yi et al, 2019;Hladik and Kolpin, 2016;Carbo et al, 2008). Those concentrations are lower than the LC50-96 h determined in Nile tilapia Oreochromis niloticus (Guedegba et al, 2019) but may constitute a risk for a good ecological status of water bodies because of its high solubility in water (Pietrzak et al, 2019).…”

Neonicotinoids: Spreading, Translocation and Aquatic Toxicity

“…Neonicotinoid levels in surface water were reviewed earlier by Morrissey and coworkers [39]. A number of monitoring studies reported the occurrence and levels of neonicotinoids in surface water ( Figure 5) [22,39,40]. Elevated detection frequencies (98.7%-100%) and maximum concentrations were reported from high maize and soybean producing regions, and the transport of the residues was found to be driven also by precipitation.…”

“…Elevated detection frequencies (98.7%-100%) and maximum concentrations were reported from high maize and soybean producing regions, and the transport of the residues was found to be driven also by precipitation. [22,39,40]. The indicated quality reference values: European Food Safety Authority (EFSA) no observable effect concentration (NOEC) [41], Rijksinstituut voor Volksgezondheid en Milieu (RIVM) Nederland maximum permissible concentration and long term exposure [42,43], US-EPA aquatic life benchmark [44], Canadian Council of Ministers of the Environment (CCME), water quality guideline [45], Australia and New Zealand proposed aquatic ecosystem protection guideline values depending on species protection goals (80%-99%) [46] and a default guideline value proposed by third parties is under peer review process [47].…”

Ultraviolet absorption of contaminants in water

“…Each has a pair of broad absorption features below 280 nm. Tryptophan is an amino acid whose UV fluorescence is similar to that of organic matter such as sewage and farm slurry 31 . This shows a broad peak around 280 nm (absorption here is also associated with fluorescence at 340 nm) and a sharper peak at 220 nm.…”

“…Metaldehyde, a pesticide for slugs and snails, absorbs rather weakly across the UV range studied and we found that it was not possible to reliably detect this compound with UV LEDs of wavelength 250 nm and above. Uric acid is present in untreated sewage but is not normally found in unpolluted waters 32 . It shows broad peaks at around 235 and 290 nm, and a peak or edge at 200 nm.…”