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Marine Pollution Bulletin 72 (2013) 99–106 Contents lists available at SciVerse ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Influence of waste management policy on the characteristics of beach litter in Kaohsiung, Taiwan Ta-Kang Liu ⇑, Meng-Wei Wang, Ping Chen Institute of Ocean Technology and Marine Affairs, National Cheng Kung University, 1 University Road, Tainan City 70101, Taiwan a r t i c l e i n f o Keywords: Transect survey Economic instrument Source reduction Waste management a b s t r a c t Marine debris is a ubiquitous problem that poses a serious threat to the global oceans; it has motivated public participation in clean-up campaigns, as well as governmental involvement in developing mitigation strategies. While it is known that the problem of marine litter may be affected by waste management practices on land, beach survey results have seldom been compared with them. In this study, marine litter surveys on four beaches of Cijin Island were conducted to explore the effects of waste management and policy implications. Indirect evidence shows that chances for land-based litter, such as plastic bags and bottles, entering the marine environment can be greatly decreased if they can be properly reduced, reused and recycled. We suggest that mitigation measures should focus on source reduction, waste recycling and management, utilizing effective economic instruments, and pursuing a long-term public education campaign to raise the public awareness of this problem. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Beaches are important tourist attractions and contribute to improving the quality of life. Clean beach is the main indicator of coastal environmental quality. However, coastal regions are susceptible to litter accumulation, and marine litter has become a global problem. The presence of marine debris can negatively affect the aesthetic appeal of beaches and reduce their recreational value and tourism quality (Pendleton et al., 2001). The anthropogenic marine litter is associated with diverse human activities and comes from a wide variety of sources both onshore and offshore. It reduces the aesthetics of the beaches and also results in many undesired environmental consequences, such as increasing adverse health risks, causing significant ecological changes, threatening marine wildlife, leading to loss of biodiversity and inflicting fishery loss (Chiappone et al., 2002; Derraik, 2002; Tudor and Williams, 2003; Abu-Hilal and Al-Najjar, 2004; Thompson et al., 2004; Cho, 2005; Tudor and Williams, 2008). Nearly 80% of the marine debris comes from land-based sources, so the key to abating the problem largely depends on effective measures of waste management on land, since most trash has the potential to enter the ocean and become marine debris (Balas et al., 2004; US Ocean Commission, 2004; Hetherington et al., 2005). Monitoring marine debris is thus extremely crucial in order to identify the sources of debris and then implement the required effective control measures accordingly ⇑ Corresponding author. Tel.: +886 6 2757575x31146; fax: +886 6 2753364. E-mail address: [email protected] (T.-K. Liu). 0025-326X/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.marpolbul.2013.04.015 (Earll et al., 2000; Tudor and Williams, 2001; Balas et al., 2001). Marine litter survey results can be used for beach management purposes, and may lead to the establishment of national and international legislation for better waste management on land and at sea. They can also stimulate the sense of responsibility to the environment and encourage public participation in the activities related to the maintenance of environmental quality, such as coastal cleanup activities. It is important to know that raising public awareness of the overall quality of the coastal environment is the only guaranteed way of reducing marine litter (Storrier and McGlashan, 2006). Many countries have established monitoring programs so the results can be used for beach management and for establishing related regulatory measures. However, most of the survey results were not compared to the land-based waste management policy. The practice of waste management on land should have prevented most of the litter from entering the marine environment, yet its influence has seldom been discussed in the literature. Besides, there has been no litter survey performed by academic researchers in Taiwan, and volunteer-based beach cleanups held by communities and local non-governmental organizations generate relatively few quantitative results. In this study, we performed a transect survey during 2009–2011 to investigate the fluctuation of marine litter on four selected beaches in Cijin, Kaohsiung in order to ascertain the type, material compositions, quantity and source of marine debris. The results were compared with the literature and Taiwan’s waste management on land to evaluate if the current practice has any influences on the characteristics of the beach litter found in the survey. 100 T.-K. Liu et al. / Marine Pollution Bulletin 72 (2013) 99–106 (USEPA). NMDMP was conducted over a 5-year period between 2001 and 2006 along the coasts of the United States, representing one of the most comprehensive and significant marine debris assessment (Sheavly, 2007). Litter items were recorded precisely, and items not shown on the predetermined data card were also noted. The marine litter was categorized by its type of material and source for litter generation activities. Statistical software packages SPSS and PRIMER v.6 were used for ANOVA and multivariate analysis, respectively. The amount of marine litter and top 10 items were then analyzed. Results of the litter survey were compared with those found in the NMDMP as well as the literature from other countries for detailed comparison. Document analysis was used to review Taiwan’s waste management practice on land; its influence on the litter found in the survey was then discussed. 2. Methods This study was carried out at Cijin Island of Kaohsiung in the southwest coast of Taiwan. Four beaches were surveyed every 2 months during the periods: August 2009–June 2010, and December 2010–October 2011. The locations of the four sites are shown in Fig. 1, where Sites 1 and 2, Cijin coastal park and tourist center, respectively, are popular recreational sites that are typically crowded with tourists. Sites 3 and 4, near a municipal wastewater treatment plant and a ship container distributing center, respectively, are more remote beaches. A transect survey similar to those found in the literature was used (Silva et al., 2008; Oigman-Pszczol and Creed, 2007; Storrier et al., 2007; Sheavly, 2007; Silva-Iniguez and Fisher, 2003; Williams et al., 2003). A 100 m 5 m transect strip above the high-tide mark parallel to the coastline was chosen at random in each site. The coordinates of each site were recorded via a global positioning system (GPS) to allow the subsequent survey in the same stretch of beach, and for use in possible GIS mapping. To evaluate the composition and abundance of beach litter, all the visible pieces of man-made debris found on each sampling site were identified and recorded in a standardized data card modified from the one used in the National Marine Debris Monitoring Program (NMDMP) of the US Environmental Protection Agency 3. Characterization of beach litter in Cijin Island 3.1. Results of Cijin beach litter survey Fig. 2 shows the total items collected in each transect survey. In the study, we collected 23,264 items of beach litter, for an overall mean litter density of 0.90 items per square meter. All sites in Cijin are likely to be influenced by similar meso-scale oceanographic 2505000 2503000 Ka o hs iun site1 2501000 r jin Ci site2 gH ar b ou a Isl nd 2499000 site3 2497000 site4 2750000 2700000 2650000 2495000 2600000 2550000 2500000 meter 2450000 2493000 171000 100000 150000 200000 250000 300000 350000 173000 0 175000 1000 2000 177000 3000 4000 179000 181000 183000 Fig. 1. Location of the survey sites in Cijin Island, Kaohsiung, Taiwan. The coordinates are TWD67 Huzishan 2-degree wide Transverse Mercator projection. 101 T.-K. Liu et al. / Marine Pollution Bulletin 72 (2013) 99–106 3,500 2,000 9,047 7,987 Marine Debris items 3,000 Marine Debris items no. mean no. sum 2,500 2,000 1,500 1,000 10,000 1,600 8,000 1,200 6,000 800 3,028 3,202 400 4,000 2,000 500 0 0 Site 1 0 Site 2 Site 3 Site 4 Fig. 3. Total and average marine debris items collected on each site in the transect survey in Cijin Island, Kaohsiung. Fig. 2. The total items collected in each transect survey during 2009–2011 in Cijin Island, Kaohsiung. events, such as: prevailing winds, cold fronts and tidal currents. During the northeast monsoon season, typically between late fall and early spring, strong and steady northeast winds prevail in Taiwan. Since repeated surveys were conducted at various sites and times, a two-way ANOVA (see Table 1) was performed to interpret the temporal and spatial variations of the debris collected. From Table 1, it can be seen that spatial variation is significant at p < 0.05 level, while monthly or seasonal variation is not statistically pronounced. It is likely that spatial variation can be attributed to other factors, such as coastal activities that may be important in the fluctuation of debris in this surveys. Survey No. 2 has the highest number of debris items, 3227. This is probably due to the impact of Typhoon Morakot on August 8, 2009 which brought the worst-ever record breaking rainfall that many weather stations registered the precipitation intensity over a flood frequency of 2000 years (Doong et al., 2011). More than 1 million tons of driftwood were cleaned up after Morakot, much of it piled up on the coast for several months (COA, 2010). Survey No. 2 was originally scheduled in early October but was postponed to October 19, until much of the driftwood was removed and sampling sites could be accessed. Survey No. 12 was performed right after the warning of Typhoon Nanmadol was lifted. Although Nanmadol was more severe than Morakot in typhoon scale, the debris items recorded were 1744, very close to the mean value of 1790 during the 2-year study. Therefore, the impact of typhoons on the beach debris is very complicated since mixed results are shown in this study. Fig. 3 shows the total and average debris items collected on each site. Sites 1 and 2 had 9047 and 7987 items, respectively. Sites 1 and 2 are popular tourist attractions where beachgoers enjoy a lot of recreactional activities. These two sites account for 73.2% of debris items, relatively higher than the combined number for Sites 3 and 4. Site 3 is in front of the municipal waste water treatment plant of Kaohsiung, a place most people would avoid visiting. This may explain why Site 3 had the least amount of debris Table 1 Results of two-way ANOVA for the transect survey. Factor Site Time Site time * Significant at p < 0.05 level. collected among the four sites, i.e. 3028 items, accounting for 13% of the total. In general, Fig. 3 shows that human’s coastal activities are an important contributing factor to the beach litter in Cijin. In this study, marine litter was categorized into eight types according to its composition: general plastic, paper, nylon, rubber, glass, polystyrene foam (PSF), metals, and others. Fig. 4 presents the proportions of types of litter in this study. Plastics in a broad sense (78.3%), including general plastic (55%), PSF fragment (20.6%), nylon (1.4%), and rubber (1.3%), were the most common litter type recorded. Other litter types recorded less frequently included paper (10.3%), glass (1.8%), metals (0.5%), and others (9.2%). The abundance of PSF in Cijin seems rare since it is not readily noted in most of the marine debris surveys cited in the references of the article. By examining the size and shape of the PSF fragments collected in this study, it can be recognized that they were originally used as floating devices in fishing gear, beverage cups, protective wrapping of fruit, and cushion like materials. Ocean Conservancy categorizes the marine debris item into five groupings: shoreline and recreational activities, ocean/waterway activities, smoking-related activities, dumping activities, and medical/personal hygiene, in the International Coastal Cleanup (ICC) events since 2001. The groupings are related to debris-producing activities and sources that identify the behavior associated with the debris’ presence (OC, 2010). Principal components analysis Others, 9.2% Metal, 0.5% Glass, 1.8%, Paper, 10.3% PSF fragment, 20.6% General plastics, 55.0% Rubber, 1.3% Nylon, 1.4% p-Value Time = month Time = season 0.042* 0.921 0.861 0.037* 0.745 0.808 General plastics PSF fragment Metal Nylon Paper Others Rubber Glass Fig. 4. The proportions of types of litter in the transect survey in Cijin Island, Kaohsiung. 102 T.-K. Liu et al. / Marine Pollution Bulletin 72 (2013) 99–106 (PCA) was applied to show spatial differences for the marine debris collected. Fig. 5 presents the ordination of sampling sites based on ICC categories and debris type. In Fig. 5a, principal component (PC) 1 and 2 explained 93.6% and 6.2% of the variability, respectively. On PC 1, the southern Sites 3 and 4 were clearly separated from the northern Sites 1 and 2. Ocean/waterway activities (OW), shoreline and recreational activities (SR), and dumping activities (DP) were the highest negative loads on PC1, while the influence on PC2 was less pronounced. In Fig. 5b, PC 1 and PC 2 explained 84.0% and 15.7% of the variability, respectively. The separation of the southern Sites 3 and 4 from other two sites according to the type of debris was also obvious. Site 1 with a high number of general plastic items is positioned in the positive part of PC2 and Site 2 with a high number of polystyrene foam items is located on the negative part of PC2. (a) 3.2. Comparison with other litter surveys Table 2 compares the top 10 debris items in this study with those in NMDMP. It can be seen that the top 3 debris items in Cijin were plastic fragment, PSF fragments, and straw, which was noticeably different from the results in NMDMP. The top 10 debris items account for 83.1% and 80.4% for the total items collected in NMDMP and this study, respectively. Among the top 10 items collected in Cijin, PSF, plastic fragments, sponge, bottle caps, wasted construction materials, and fireworks caps and stems were not shown in the top 10 of NMDMP. The 10th item in MNDMP, i.e. cotton swabs, was not shown in Cijin at all during the 2-year study. The only common items shown in both study were straw and plastic bags. In this study, 7 out of the top 10 debris item came from land-based sources, while in NMDMP only 4 items out of the top 1000 Site 2 OW Site 4 0 Site 3 SM PC2 Site 1 MP SR -1000 DP -2000 -2000 -1000 0 1000 2000 PC1 (b) 1000 Site 1 Site 4 Site 3 GPT 0 PC2 PAP RBB MET NL GLA Site 2 -1000 OTR PSF -2000 -2000 -1000 0 1000 2000 PC1 Fig. 5. PCA ordination of sampling sites and variable vectors. Variables involved (a) ICC category: shoreline and recreational activities (SR), ocean/waterway activities (OW), smoking-related activities (SR), dumping activities (DP), and medical/personal hygiene (MP); and (b) type of debris: general plastic (GPT), paper (PAP), nylon (NL), rubber (RBB), glass (GLA), polystyrene foam (PSF), metals (MET), and others (OTR). 103 T.-K. Liu et al. / Marine Pollution Bulletin 72 (2013) 99–106 Table 2 Comparison of the top 10 debris items found in this study with those in the NMDMP. Rank Top 10 marine litter in NMDMP Top 10 marine litter in this study Item Percentage (%) Items Percentage (%) 1 2 3 4 5 6 7 8 9 10 Straws Plastic beverage bottles Plastic bags (<1 m) Balloons Metal beverage cans Rope (>1 m) Plastic bottles Other plastic bottles Fishing line Cotton swabs 27.5 13.0 9.0 7.8 7.4 5.5 4.6 3.4 3.4 2.7 Plastic fragment PSF fragment Straw Cigarette filter Bottle cap Plastic bag Construction Sponge Fireworks caps Fireworks stems 25.5 19.0 10.1 5.1 4.8 4.5 4.3 3.0 2.8 1.7 Total 84.2 Marine Debris percentage 100% Medical/personal hygiene 90% Dumping 80% Smoking-related Ocean/waterway 70% Shoreline and recreational 60% 50% This study 2010 ICC Fig. 6. Comparison of the transect survey in this study with 2010 ICC survey according to the five-grouping category. 10 are from land-based sources. This comparison shows a distinguishable pattern of the main debris items between the coast in Taiwan and United States, which is probably due to different life styles, cultures, coastal activities and waste management practices. 80.8 Fig. 6 compares this study with the 2010 ICC event according to the five-grouping category. It can be seen that shoreline and recreational activities (64.3%) is the highest debris-producing activity among all of the others in this study, implying that visitors play an important role in debris generation. This is in agreement with Fig. 3, that Sites 1 and 2, with more beachgoers, have more debris items than the other two sites. The differences between this study and the 2010 ICC are that more ocean activity and less smoking-related activities are noted in this study (OC, 2010). The higher proportion of marine litter coming from ocean activity indicates that the surveyed area may have more fishing activities. Table 3 compares the composition of debris items with those found in other researches. It can be seen that plastic debris remains the top category. The second category for the debris varied for most the studies. It is paper in this study (10.3%) and Orange County, California (24.9%); metal in Rio de Janeiro State, Brazil (18%); glass in Queensland beach, Australia (6.4%); or other uncategorized debris (Oigman-Pszczol and Creed, 2007; White, 2006; Moore et al., 2001). People in different regions may have different habits and coastal activities, and therefore variations found in Table 3 can be attributed to life style diversity in the survey areas. Nonetheless, it is obvious that plastic debris presents a severe ubiquitous problem around the world. Table 3 Comparison of the composition of debris items in this study with those found in other researches. a Location Plastics (%) Paper (%) Glass (%) Metal (%) Other (%) References This study Cassino beach, S. Brazil Dutch coast Firth of Forth, Scotland Rio de Janeiro State, Brazil Queensland beach Gulf of Oman Coast of Japan sea Orange County, California, US 78.3a 57.6 67 54.2 64 89.7 61.8 92.9 66.2 10.3 17.2 8 4.7 6 0.5 2.1 1.0 24.9 1.8 1.3 4 9.4 3 6.4 2.7 2.2 1.6 0.5 1.6 6 5.5 18 3.2 3.4 1.0 5.2 9.2 22.3 15 26.3 9 0.2 29.9 2.4 2.1 This study Tourinho and Fillmann (2011) Gorycka (2009) Storrier et al. (2007) Oigman-Pszczol and Creed (2007) White (2006) Claereboudt (2004) Kusui and Noda (2003) Moore et al. (2001) Including polystyrene foam (20.6%), rubber (1.3%), nylon (1.4%), and other general plastics (55.0%). Table 4 Comparison of some specific debris items found between NMDMP and this study that may have policy implications. Debris item NMDMP Plastic bags Plastic bag < 1 m; 9.1% Plastic bag > 1 m; 1.4% 10.5% This study Plastic bag fragment 4.5% Plastic bottles Plastic beverage bottles; 13% Plastic food bottles; 3.5% Other plastic bottles; 3.4% 19.9% Plastic caps; 4.8% Plastic bottles; 1.9% Plastic cups; 0.3% 7.0% Metal Beverage cans 7.4% Beverage cans 0.1% 104 T.-K. Liu et al. / Marine Pollution Bulletin 72 (2013) 99–106 4. Influence of waste management policy 4.1. Plastic Restriction Policy and Compulsory Trash-sorting Policy It is noted in this study that waste management policy on land may influence the marine debris pattern found in the beach litter survey. Table 4 compares some of the policy-related debris items found between NMDMP and this study. It is noted that plastic bags are 10.5% and 4.5%, respectively; plastic bottles are 19.9% and 7.0%, respectively; and metal beverage cans are 7.4% and 0.1%, respectively, for NMDMP and this study. These three types of wastes are significantly fewer in number of items in this study, which is likely due to the two waste management policies in Taiwan, i.e. the policy on restricting the use of plastic shopping bags and disposable plastic tableware (as known as ‘‘Plastic Restriction Policy’’) and the Compulsory Trash-sorting Policy. According to the 2001 environmental statistics of Taiwan’s Environmental Protection Agency (TEPA), plastics accounted for 21.1% of household garbage (TEPA, 2001). In 2002, TEPA started to implement the Plastic Restriction Policy under the Waste Disposal Act in order to prohibit the use of plastic shopping bags and disposable plastic tableware in all government agencies and public facilities. Three years after the policy was implemented, 72% of shoppers carry recyclable shopping bags compared to only 20% prior to the policy. The reduction in the use of plastic shopping bags is approximately 2 billion, corresponding to about 58% of source reduction (TEPA, 2012). The 2011 TEPA annual report indicates that plastics account for 15.7% of household garbage, showing a significant reduction compared to the 21.1% in 2001 (TEPA, 2011). Although this is not direct evidence, the policy helps to explain why the number of plastic bags is lower in this study (4.5%) compared to NMDMP’s 10.5% (see Table 4). The TEPA 2002 Resource Recycling Act required that public places should provide recycling bins to hold resources before they are taken to recycling centers. In 2005, TEPA started to implement the Compulsory Trash-sorting Policy under the Resource Recycling Trash (kg) per capita per day) (a) 1 0.9 0.83 083 0.8 0.75 0.71 0.67 0.6 0.6 0.58 0.52 0.5 0.48 0.4 0.2 0 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Percent Recycleing (b) 50% 42.0% 38.7% 40% 48.8% 45.5% 35.4% 31.1% 31.4% 31.6% 32.5% 33.3% 33.2% 33.8% 34.0% 30% 29.4% 24.0% 20% 20.1% 10% USA Taiwan 0% 2003 2004 2005 2006 2007 2008 2009 2010 Fig. 7. Municipal solid waste management statistics: (a) wastes generated per capita per day in Taiwan; and (b) percent recycling for Taiwan and USA. Act, requiring that the general public needs to sort the garbage into three categories: food waste, resources and general waste. In order to help people practice trash sorting, the personnel of curbside waste collection vehicle randomly check the contents of the garbage bag prior to collection. A penalty of 1200–6000 NT ($40– $200) is charged for unsorted trash bags. Through implementing various policies under the Resource Recycling Act, including Compulsory Trash-sorting Policy, the waste disposal rate was reduced from 0.9 kg per capita in 2001 to 0.48 kg per capita in 2010 (see Fig. 7a). When comparing the recycling ratio in Taiwan and the US in 2010 (see Fig. 7b), it can be seen that the ratios are 48.8% and 34.1%, respectively (TEPA, 2011; USEPA, 2010). The recycling ratio has greatly increased from 20.1% in 2003 to 48.8% in 2010, while the values have not changed much for the US. Containers made of iron, aluminum, glass, and plastic, which are commonly found during a beach transect survey, are all mandatory recyclable items under the 2002 Resource Recycling Act. In Table 4, the recyclable resources found during the survey are: plastic caps, bottles, cups and metal beverage cans, representing 7.1% of total debris items, while the recyclables are 27.3% in the NMDMP, a much higher proportion than those collected in this study. The 2002 Resource Recycling Act and Compulsory Trash-sorting Policy cultivated the trash sorting practice among the general public in Taiwan; this seems to explain why the recyclable waste presents a significant lower percentage of the debris found in this study. 4.2. Problem of wastes from fishing activities In this study, PSF fragments represent 20.6% of the debris collected. The PSF fragments seem to have originated from the PSF floats used in oyster culture fisheries. Oyster farming fishery is a major type of aquaculture in the southwestern coast of Taiwan (FA, 2011). The floating culture system, i.e. raft culture supported by PSF floats to maintain buoyancy, is the main method used to grow oysters. Most of the PSF fragments can be recognized as bits broken off the PSF floats used in oyster farming. However, this fishery is absent in Cijin Island, and the closest existing one is in Tainan City, approximately 60 km north of Cijin, Kaohsiung. The PSF debris has been a problem in the coast of Tainan where the torn culture rafts and PSF floats were waste on the sites every year after the harvest of oysters, typically in the late summer. In order to alleviate this problem, ‘‘Oyster Farming Management Regulations’’ was promulgated in Tainan to address the derelict fishing gear (DFG) problem. In this regulatory regime, the floating culture systems are required to be stamped with identification marks and all the rafts, PSF floats and wastes after harvest should be collected and brought to the designation areas for disposal. Oyster culture systems that do not have recognizable identification marks are discarded by the regulations. The ordinance does not provide desirable results, mostly due to relatively low penalties for noncompliance and weak enforcement of the provisions. The penalty for violators who failed to bring the wasted culture systems to the designation area is only 1000 NT ($33) per raft (Wang, 2010). The ordinance does not cause any deterrent effects it was intended to since most fishers decided not to bring the wasted rafts and PSF floats back to the designated areas; therefore, the problem remained after the implementation of the regulations. Disposal of these wastes after harvesting the oysters resulted in a devastated coast full with PSF wastes in Tainan, and even affected the bordering areas such as Cijin Island. In order to resolve the problem of wasted PSF fragments found in this study, a better management approach for the oyster culture fisheries in Tainan is necessary. For example, the provisions should be strictly enforced and the penalty should be increased to a level that can induce compliance. In addition to trying other useful economic instruments, substitutes to replace or improve the PSF as a T.-K. Liu et al. / Marine Pollution Bulletin 72 (2013) 99–106 floating device are an alternative option. It is necessary for the substitutes to be more weathering resistant without compromising the original floating function. Some examples are biodegradable plastic tubes, compacted foam materials, recycled waste tires, and PSF wrapped with canvas. The improved durability and integrity of the substitute may ease the efforts of maintenance for noncompliance since it is not likely for them to break up and spread out when weathered. 4.3. Policy implication and future management efforts In the Fifth International Marine Debris Conference, the Honolulu Strategy was formulated: it aimed to address the issue of marine debris at the global, national and local levels (UNEP/NOAA, 2011). The Honolulu Strategy aimed to ‘‘develop, strengthen, and enact legislation and policies to support solid waste minimization and management’’. The waste hierarchy (i.e. reduce, reuse and recycle, in the order of importance) classifies waste management strategies according to their desirability (Kreith and Tchobanoglous, 2002). If the wastes can be properly reduced, reused and recycled, the chance for them to enter the marine environment can be greatly abated. In this study, policies under Taiwan’s Waste Disposal Act and Resource Recycling Act show the indirect result that improved solid waste management can alleviate the problems of marine debris. However, the volumes of trash that keep appearing on beaches indicate that there is still room for better solid waste management. It is possible that a lack of consistent monitoring and identification of sources of debris may hamper the implementation of effective control measures for source reduction (US Ocean Commission, 2004). Monitoring helps policy-makers to design management measures that address the most prevalent forms of debris, as well as those that cause the most harmful effects in the marine environment. In addition, the comprehensive enforcement of policies and regulations concerning individual behavior would be impractical: it is necessary to pursue a long-term education campaign for the general public in order to guide people and communities regarding the correct way to dispose of waste. Education campaigns should also extend to target specific stakeholders that are prone to generate marine debris, such as coastal recreational operators, packaging companies and the fishing industry, such as Tainan’s oyster culture fishery in this study. Product modification and improvement is one of the important methods for the source reduction of wastes (Kreith and Tchobanoglous, 2002). In this study, it is noted that plastic caps contribute 4.8% of the debris collected, while plastic bottles are only 1.9%. It seems that while plastic bottles are recycled as resources, the plastic caps somehow are neglected and released into the environment since they are relatively small. Moore (2003) shows that bottle caps are visible inside the decomposed carcasses of albatrosses on Kure Atoll in the North Pacific. Jordon (2012) shows in a documentary that a large volume of plastic caps ends up in the remote uninhabited Midway Island where many albatrosses mistakenly ingest them as food, suffer, and die. In the 1970s, the pull-tab opening method for metal beverage can was widely popular. A significant problem rose as people would frequently discard the pulltabs on the ground as litter. The invention of the push-tab opening mechanism in the 1980s solved the problem since the non-removing stay-on-tab prevented the tabs from littering. Bottle caps represent a significant marine debris problem in this study as well as around the world. In order to prevent bottle caps from being released into the environment, the caps should be redesigned as an integral part of the bottle and recycled along with the bottles as well, similar to the stay-on-tab in metal beverage cans. Currently, the cleanup of the marine debris largely relies on parties who do not cause the problem, typically volunteers or coastal maintenance authorities. There is insufficient liability to the pol- 105 luters who are responsible for generating the marine debris. In order to compensate for the economic costs associated with marine debris, the development and implementation of economic instruments seem to provide opportunities for addressing the problem (ten Brink et al., 2009). These instruments include extended producer responsibility fees, deposit refunds, waste collection taxes and recycled product tax rebates (UNEP/NOAA, 2011). The goal of applying an economic instrument is to change the behavior of coastal users regarding the correct handling and disposal of their wastes. For the DFG problem in Tainan, the current implemented economic instrument does not achieve the desirable results. The negative impacts associated with the problem justify trying other useful economic instruments that can reduce this DFG problem. Economic incentives may encourage the cleanup of wasted materials with deposit refund value. Tainan’s government can impose such a deposit refund program for the oyster culture systems. The deposit can only be refunded when the DFG wastes are collected and brought to the designated areas. The penalty collected for non-compliance can serve as a fund for the maintenance of beach cleanness and enforcement of the regulations. It is believed that using such an incentive program to promote compliance can support waste minimization. However, it may not incentivize long-term sustainable behavior of coastal users (Cho, 2009). Pursuing a long-term education campaign is still necessary to correct the individual behavior of waste handling. 5. Conclusion In this study, it can be seen that the marine debris survey in Cijin Island is significantly different from NMDMP in terms of the collected items and its distribution pattern, which can be attributed to differences in coastal activities, cultural style, habits in waste handing, and policy of waste management on land. By comparing foreign management experiences and litter characteristics, we conclude with some management implication and strategy for alleviating the marine litter problem. Although marine debris is a global issue, its adverse effects typically cause impacts at the local level and require local involvement. Greater involvement with local governments and partnerships with communities and industry will also help to reduce marine debris. 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