*Article* **Analytical Detection of Sulfonamides and Organophosphorus Insecticide Residues in Fish in Taiwan**

**Chung-Pei Chang 1,**†**, Po-Hsun Hou 2,3,**†**, Wei-Cheng Yang 4, Ching-Fen Wu 5, Chia-Chia Chang 6, Ming-Yang Tsai 7,8, Hsiao-Pei Tsai 9, Chien-Teng Lin 5, Yi-Jing Xue 5, Jiann-Hsiung Wang <sup>5</sup> and Geng-Ruei Chang 5,9,10,\***


Academic Editor: Ping-Chung Kuo

Received: 26 February 2020; Accepted: 23 March 2020; Published: 25 March 2020

**Abstract:** Exposure to residues of antibiotics (e.g., sulfonamides) and insecticides (e.g., organophosphorus insecticides) in aquacultured food can adversely affect humans and animals and thus affect public health globally. Here, using a validated method, we examined the levels of residues of 12 sulfonamides as well as 18 organophosphorus insecticides in aquacultured fish in Taiwan. A total of 52 fish samples (i.e., 20 tilapia, 16 milk fish, and 16 perch samples) were obtained from Taiwanese aquafarms from June 2018 to October 2019. We detected 0.02 and 0.03 mg/kg of sulfamethazine (a sulfonamide) in one tilapia and one milk fish, respectively, and 0.02, 0.05, and 0.03 mg/kg of chlorpyrifos (an organophosphorus insecticide) in one tilapia, one milk fish, and one perch, respectively; thus, among the samples, 3.85% and 5.77% contained sulfonamides and organophosphorus insecticide residues, respectively. Furthermore, we assessed human health risk based on the estimated daily intakes (EDIs) of these residues: EDIs of sulfonamide and organophosphorus insecticide residues were <1.0% of the acceptable daily intake recommended by the Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives. The risk of exposure to sulfonamide and organophosphorus insecticide residue by consuming aquacultured fish in Taiwan was thus negligible, signifying no immediate health risk related to the consumption of fish. Our findings can constitute a reference in efforts geared toward ensuring food safety and monitoring

veterinary drug and insecticide residue levels in aquacultured organisms. Residue levels in fish must be continually monitored to further determine possible effects of these residues on human health.

**Keywords:** sulfonamide; organophosphorus insecticide; residue; fish; risk assessment

#### **1. Introduction**

The aquaculture industry is of great economic importance and has been growing faster than other animal-farming industry worldwide [1]. Taiwan's environment and geographic location are highly appropriate for aquaculture advancement, with the country's aquaculture history spanning more than three centuries [2]. In Taiwan, more than 35 major and candidate aquatic species are commercially aquacultured [3]. Over 2010–2018, Taiwan's revenue derived from land aquaculture was up to US\$1 billion on average [3]; in addition, during the 2010s, Taiwan's estimated annual land aquaculture production was 300,000 t [4]. Moreover, in Taiwan, major developments in aquaculture occurred over the 1960s to the 1990s [2], mainly because of the strong support of the government since the 1960s [5]. In particular, the government strongly supported the farming of fish, such as tilapia, milkfish, perch, eels, and groupers. From the beginning of tilapia farming in 1978 until 2018, Taiwan's average annual tilapia production increased to 60,000 t [3].

Taiwan has a subtropical climate and a limited amount of usable land; thus, aquaculture farms in Taiwan are located close to agricultural and residential areas, predisposing the cultured organisms to fungal, bacterial, parasitic, and viral infections. This thus necessitates applying prophylactic and therapeutic veterinary drugs, such as antibiotics [6]. Nevertheless, excessively applying these drugs could result in the cultured organisms retaining drug residues at harvest, potentially exposing consumers to substances toxic for human consumption [2]. We previously detected chloramphenicol in hard clam [6] and shrimp [2] and quinolones in shrimp [2] aquafarms in Taiwan. Moreover, these aquafarms use several insecticides to control ectoparasites and endoparasite growth [7] and several pesticides to limit the growth of aquatic weeds in bodies that include canals, fishponds, and lakes [6]. These activities lead to the introduction of these chemicals into water and soil and consequently contaminate aquaculture regions. Aquaculture techniques that are usually executed in Taiwan's inner regions include polyculturing with waterfowls and mixed breeding with different aquatic products; this may also introduce chemical pollution to the soil as well as water environments and thus negatively affect aquacultured organisms [8]. In aquaculture, excessively applying chemicals may engender public health concerns as well as ecological impacts; for example, bacterial resistance could be induced and chemical residues may be added to the environment, thus increasing allergy and cancer risks. Therefore, research should be executed on whether aquacultured fish contain veterinary drug and insecticide residues—possibly bioaccumulated in their edible parts.

The recent continual decrease in the availability of wild-caught fish has led to a rise in aquaculture fish production as well as a rise in their consumption. However, in Taiwan, major food safety incidents over the past decade have been related to aquatic product consumption [9] and economic losses have been incurred because the import of some Taiwanese aquacultured food products has been banned by several countries worldwide [10]. Consequently, Taiwan's government is paying increasing attention toward aquacultured product safety and quality assessment and management. Sulfonamides, synthetic derivatives of sulfonic acid, are used broadly because they are low-cost, are effective against some bacterial infections, and improve animal performance. In the Asia Pacific region, sulfonamides are commonly used against bacterial infections and other diseases in aquaculture [1]. In China, for instance, sulfur drugs were detected in all fish samples from typical marine aquaculture regions [11]. However, sulfonamides have several side effects; for example, they have been demonstrated to engender reduced filet palatability of aquacultured products, increased kidney damage and infertility risk, and physiological and immunological response disruptions [1,12]. Massive and repeated illegal

use of organophosphorus insecticides to control parasitic diseases in aquacultured organisms has also been noted in Taiwan [4]; these insecticides mainly inhibit acetylcholinesterase activity and disrupt nerve function in humans [13].

The Taiwan Food and Drug Administration (TFDA) has yet to establish the maximum residue limits (MRLs) for sulfa drugs (except for sulfadimethoxine and sulfamonomethoxine) or organophosphorus insecticides in fish. However, in 2019, the TFDA defined the MRLs of sulfa drugs in livestock, chicken, milk, and eggs and completely banned the use of sulfa drugs in fish aquaculture. Therefore, in this study, we determined the concentrations and accumulation levels of sulfonamides and organophosphorus insecticides in major aquacultured fish in Taiwan. In addition, we examined these contaminants' estimated daily intake (EDI) through seafood consumption in Taiwanese adults. Our findings provide information that can be potentially useful during the development of effective measures for safe aquaculture and aquacultured product consumption. Moreover, our results highlight the potential phthalate burden imposed on consumers due to excessive plastic material use in Taiwan.
