Antifouling paint biocides (Irgarol 1051 and diuron) in the selected ports of Peninsular Malaysia: occurrence, seasonal variation, and ecological risk assessment.

Irgarol 1051 and diuron are photosystem II inhibitors in agricultural activities and antifouling paints in the shipping sector. This study focused on three major ports (western, southern, and eastern) surrounding Peninsular Malaysia to construct the distribution of both biocides on the basis of the seasonal and geographical changes. Surface seawater samples were collected from November 2011 to April 2012 and pretreated using the solid-phase extraction technique followed by quantification with GC-MS and LC-MS-MS for Irgarol 1051 and diuron, respectively. Generally, the distribution of Irgarol 1051 was lowest during November 2011 and highest during April 2012, and similar patterns were observed at all ports, whereas the distribution of diuron was rather vague. The increasing pattern of Irgarol 1051 from time to time is probably related to its accumulation in the seawater as a result of its half-life and consistent utilization. On the basis of the discriminant analysis, the temporal distribution of Irgarol 1051 varied at Klang North Port, Klang South Port, and Pasir Gudang Port, whereas diuron was temporally varied only at Kemaman Port. Furthermore, Irgarol 1051 was spatially varied during November 2011, whereas diuron did not show any significant changes throughout all sampling periods. Ecological risk assessment exhibited a high risk for diuron and Irgarol 1051, but Irgarol 1051 should be of greater concern because of its higher risk compared to that of diuron. Thus, it is recommended that the current Malaysian guidelines and regulations of biocide application should be reevaluated and improved to protect the ecosystem, as well as to prevent ecological risks to the aquatic environment.

Data on monthly physicochemical variation of Tropical Island groundwater of Pulau Bidong, South China Sea.

The groundwater samples of Pulau Bidong, Terengganu, Malaysia were collected from five sampling stations from June to October 2016. Physical parameters such as temperature, specific conductivity, dissolved oxygen (DO), pH, salinity, and DO saturation were measured in-situ by using handheld device. Meanwhile, total suspended solid (TSS), total dissolved solid (TDS), nitrate (NO3 -), nitrite (NO2 -), ammonium (NH4 +) and phosphate (PO4 3-) were analysed and detected using UV-Vis Spectrophotometer. The inorganic nutrients (NO3 -, NO2 -, NH4 + and PO4 3-) were ranged from 0.000 to 4.310 mg/L, 0.000 to 0.190 mg/L, 0.000 to 0.807 mg/L and 0.003 to 0.028 mg/L, respectively. The monthly trends of specific conductivity, DO, salinity, DO saturation, NO3 -, NO2 - and NH4 + demonstrated significant variation in June (the lowest rainfall) compared to other months. Correlation matrix revealed that temperature was associated with the specific conductivity, and NH4 + strongly correlated with DO, NO3 - and NO2 -. Nevertheless, there is a strong negative correlation between physicochemical parameters and monthly rainfall distribution. Notably, future studies are required for long-term monitoring to ensure the good quality of groundwater from Pulau Bidong. The spatial and temporal variability of the present data has been reported by Tan et al. [1].