Levels of organic phosphorus, the pollution status, and the potential health risks in Urumqi's snow water in the years 2019-2022

Due to the lack of research on organic pollutants in snow water and the rapid economic growth of oasis cities in dry areas, this study looked at the pollution characteristics and sources of organophosphorus flame retardants in the urban snow of Urumqi, a typical oasis city. The results showed that: (1) The average (mean) values of 10 organophosphorus flame retardants detected in the snow of Urumqi from 2019 to 2022 were TMP-50.09(45.52) ng/L, TEP-41.79(39.75) ng/L, TnBP - 41.48(43.32) ng/L, TEHP - 69.19(65.64) ng/L, TCEP - 64.64 (61.21)ng/L, TCPP-78.20(72.32) ng/L, TDCPP-140.62(132.22) ng/L, TCP-28.61(25.67) ng/L, TPhP - 29.83(31.22) ng/L, and EHDPP-6.21(8.65) ng/L, respectively. (2) According to an analysis of the single factor pollution index and comprehensive pollution index, the single factor pollution index values for TCEP, TCPP, and TDCPP in 2020, TCPP and TDCPP in 2021, and TCEP, TCPP, and TDCPP in 2022 are all larger than 1, which results in pollution. 10 organophosphorus flame retardants' complete pollution index values were found in the snow in Urumqi. The composite index value for January, February, and December of 2019 was 4.56, which is considered to be extremely high pollution. The overall index value of 3.16 in January, February, and December of 2022 indicated severe pollution, whereas other years belonged to low to moderate pollution levels. (3) The health risk assessment of organophosphorus flame retardants in snow showed that the ADDs of 10 OPEs ranged from 29.87 to 34.22 ng/(kg·d) under the average exposure level, and from 30.92 to 48.39 ng/(kg·d) under the high exposure level. The ADDs of 10 OPEs were much below the threshold for carcinogenic and non-carcinogenic risk computation, falling between 1.00×10 -2 and 10 -6 range. (4) Based on PCA and correlation analysis, we know that PC1 (TBOEP, TCPP, TCEP, TDCPP and EHDPP) is primarily from atmospheric migration and dry and wet deposition; PC2 (TMP, TEP and TPhP) mainly comes from VC materials and thermoplastic synthetic rubber; PC3 (TnBP and TCP) largely comes from atmospheric transport and dry and wet deposition.