Fates and ecological effects of current-use pesticides (CUPs) in a typical river-estuarine system of Laizhou Bay, North China

Abstract

Current-use pesticides (CUPs) are widely applied in agriculture; however, little is known about their environmental behaviors, especially in the freshwatereseawater transitional zone. Water and sediment samples were collected in an intensively human impacted river (Xiaoqing River) from the headwaters to Laizhou Bay to investigate the distributions and environmental fates of four CUPs: trifluralin, chlorothalonil, chlorpyrifos, and dicofol. These CUPs were frequently detected in water and sediment samples. P CUPs in water and sediment samples ranged from 1.20 to 100.2 ng L À1 and 6.6e2972.5 ng g À1 dry weight (dw), respectively. Chlorpyrifos and chlorothalonil were the most abundant CUPs in water and sediment samples, respectively. Spatial distribution of CUPs in the Xiaoqing River aquatic ecosystem was mainly influenced by point sources, agricultural activities, the dilution effect by seawater, and environmental parameters. Field-based sediment water partitioning coefficients, normalized by organic carbon (log Koc), were calculated. Interestingly, temperature and salinity exhibited significant impacts on the distribution of log Koc of the four CUPs. The effect of temperature on the distribution of log Koc of the four CUPs varied between the CUPs. In most water samples, the levels of chlorpyrifos exceed the freshwater screening benchmarks. Hence, urgent control measures need to be devised and implemented.

Anthropogenic stressors impact fish sensory development and survival via thyroid disruption

“…Likewise, while CPF levels in contaminated surface waters are generally below 1 μg L −1 with limited persistence in the water column, these levels can spike up to 26 μg L −1 in rivers 53 . This suggests that following run-offs, and on a short timescale such as the 32-h exposure of our study, CPF levels in coastal waters could largely exceed the pg/ng per liter concentrations usually reported in seawater [54][55][56] . Acute exposure to increased temperatures of +1.5 and +3 °C or CPF levels spanning from 1 to 30 μg L −1 therefore reflects the temperature fluctuations 49,50 and potential or future pesticide fluctuations 53 that larval fishes may experience when recruiting to coastal nurseries under high anthropogenic influence.…”

Evaluation of Solvents Used as Keepers in the Determination of Organic Pollutants by GC/MS

“…There are only a few works that describe the use of keepers in the OPP determination procedure. For example, hexane was used as an added substance to prevent sample evaporation [ 10 ] and degradation in water samples [ 5 ].…”

“…A keeper (100 µL of isooctane, toluene, nonane, 1-octanol, or dodecane) was added to the evaporation vial before the evaporation process. This keeper volume was selected after analyzing the data presented in the aforementioned review article [ 5 ] and in recent articles [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ] (100 µL was the most frequently used volume). The volume of the keeper added was also adjusted to the size of the vial (7 mL) in which the evaporation was taking place.…”

“…Recently, several new research papers describing analytical procedures with the solvent evaporation step and the use of a keeper have been published. The determination of organic pollutants in samples of various types has been described in studies considering PAHs in contaminated soil samples [ 8 ] and particulate matter [ 9 ]; chlorpyrifos and other pesticides in river water and sediments [ 10 ]; pyrethroid metabolites in human urine [ 11 ]; organochlorine pesticides (OCPs) and PCBs in human serum [ 12 , 13 , 14 ]; PCBs and other persistent organic pollutants (POPs) in fish [ 15 ]; and PCBs in waste, leachate and aerosols [ 16 ]. In these and other works, the keeper was selected arbitrarily on the basis of previous works, recommendations, standards and regulations [ 5 ].…”

Pesticides: formulants, distribution pathways and effects on human health – a review

“…Dissolved CUPs are widely present in water bodies. For example, comparative studies of China aquatic systems report high detection frequencies of napropamide, atrazine [ 79 ], chlorpyrifos, dicofol [ 74 , 80 ]. In a similar study in Argentina, less than 30 % of all detected pesticides were quantified, and glyphosate and AMPA showed the highest concentrations in surface water [ 81 ].…”